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General Discussion => Advanced Concepts => Topic started by: EdT on 06/27/2012 11:52 PM

Title: EM Drive Developments Thread 1
Post by: EdT on 06/27/2012 11:52 PM
Any current news on the development of the EMDrive ?

Latest entry by the company was in June 2011.  SPR has not responded to my request for any new developments.

http://www.wired.com/dangerroom/2008/09/chinese-buildin/
http://www.emdrive.com/

emdrive_2.jpg
Title: Re: EM Drive Developments
Post by: QuantumG on 06/27/2012 11:56 PM
I hear North Korea is building one too.

Title: Re: EM Drive Developments
Post by: docmordrid on 06/28/2012 12:10 AM
I *think* there was an article about an Infinite Improbability Drive around here somewhere..  ;)

Answer: not much that is credible.
Title: Re: EM Drive Developments
Post by: JBF on 04/29/2013 12:45 AM
New information up on http://www.emdrive.com/ (http://www.emdrive.com/)

November 2012

China publishes high power test results

The prestigious Chinese Academy of Sciences has published a paper by Professor Yang Juan confirming their high power test results. At an input power of 2.5kW, their 2.45GHz EmDrive thruster provides 720mN of thrust. The results have clearly been subject to extensive peer review following the NWPU 2010 paper. The measurements were made on a national standard, thrust measurement device, used for Ion Engine development. Details of the measurement system and calibration data are given in the paper. A professional English translation is given here: http://www.emdrive.com/yang-juan-paper-2012.pdf

Well, newer than the last comment in any case.
Title: Re: EM Drive Developments
Post by: grondilu on 05/03/2013 09:42 PM
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1045227#msg1045227">Quote from: JBF on 04/29/2013 12:45 AM</a>
At an input power of 2.5kW, their 2.45GHz EmDrive thruster provides 720mN of thrust.

A photon has energy E = hf and momentum  p = hf / c = E / c

F = dp/dt = dE/dt / c

So even if all the energy was converted into photons all emited in the desired direction, that would make a force:

F = 2.5e3/3e8 = 8e-6 N

That's 90 000 times less than 720 mN.

Where am I wrong?



Title: Re: EM Drive Developments
Post by: Nathan on 05/03/2013 10:10 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1047345#msg1047345">Quote from: grondilu on 05/03/2013 09:42 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1045227#msg1045227">Quote from: JBF on 04/29/2013 12:45 AM</a>
At an input power of 2.5kW, their 2.45GHz EmDrive thruster provides 720mN of thrust.

A photon has energy E = hf and momentum  p = hf / c = E / c

F = dp/dt = dE/dt / c

So even if all the energy was converted into photons all emited in the desired direction, that would make a force:

F = 2.5e3/3e8 = 8e-6 N

That's 90 000 times less than 720 mN.

Where am I wrong?


Read the papers. You are missing the q factors, relativity etc. work thru the math in the paper then make a post. I did it and even though I'm not entirely convinced I am thinking that it is a possibility- especially given that the effect has been independently confirmed.
It needs a serious look.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 07/31/2014 03:04 PM
New paper describing encouraging results from the testing of an 'EM-drive' like device.
http://ntrs.nasa.gov/search.jsp?R=20140006052 (http://ntrs.nasa.gov/search.jsp?R=20140006052)
Hope it stands up to further scrutiny. Could be a real game changer!
Title: Re: EM Drive Developments
Post by: Stormbringer on 07/31/2014 04:38 PM

say...one of the names of that paper as opposed to the Wired article on this has:

Quote
Brady, David   (NASA Johnson Space Center, Houston, TX, United States);   
White, Harold G.   (NASA Johnson Space Center, Houston, TX, United States);   
March, Paul   (NASA Johnson Space Center, Houston, TX, United States);   
Lawrence, James T.   (NASA Johnson Space Center, Houston, TX, United States);   
Davies, Frank J.   (NASA Johnson Space Center, Houston, TX, United States)

Harold white of QVPT and warp drive fame and Paul March of Machs Principle fame.

i sense a disturbance in the force...

it's as if the forces of maverick science reached out and slapped establishment science with a wet tuna.  :)

Title: Re: EM Drive Developments
Post by: Star One on 07/31/2014 05:13 PM
Well it's appeared again.

http://www.wired.co.uk/news/archive/2014-07/31/nasa-validates-impossible-space-drive

This is the main link.

http://ntrs.nasa.gov/search.jsp?R=20140006052

Anyone notice Harold 'warp drive' White is one of the authors on this?
Title: Re: EM Drive Developments
Post by: KelvinZero on 07/31/2014 05:43 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237027#msg1237027">Quote from: IslandPlaya on 07/31/2014 03:04 PM</a>
New paper describing encouraging results from the testing of an 'EM-drive' like device.
http://ntrs.nasa.gov/search.jsp?R=20140006052 (http://ntrs.nasa.gov/search.jsp?R=20140006052)
Hope it stands up to further scrutiny. Could be a real game changer!
Yep.. free energy. Forget the heat death of the universe, we will just keep creating additional mass locally.

Hmm.. actually perhaps this answers the Fermi paradox.
It may simply be impossible for a species spread across the stars with access to free energy and mass to have the discipline to not create more living space exponentially, and eventually suck its local group into a black hole.  :)

Title: Re: EM Drive Developments
Post by: Dunners73 on 07/31/2014 05:44 PM
Not sure this is related to the emdrive, think this is that Q thruster concept.
regardless, the abstract makes it sound more negative than positive.

"..Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article)."

Like the placebo in a drug trial showing the same "effect".

Title: Re: EM Drive Developments
Post by: Star One on 07/31/2014 05:45 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237091#msg1237091">Quote from: Dunners73 on 07/31/2014 05:44 PM</a>
Not sure this is related to the emdrive, think this is that Q thruster concept.
regardless, the abstract makes it sound more negative than positive.

"..Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article)."

Like the placebo in a drug trial showing the same "effect".

From my limited understanding of the topic I wasn't sure why these two were linked together in the Wired article, are they really that closely related?

Title: Re: EM Drive Developments
Post by: Stormbringer on 07/31/2014 05:54 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237092#msg1237092">Quote from: Star One on 07/31/2014 05:45 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237091#msg1237091">Quote from: Dunners73 on 07/31/2014 05:44 PM</a>
Not sure this is related to the emdrive, think this is that Q thruster concept.
regardless, the abstract makes it sound more negative than positive.

"..Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article)."

Like the placebo in a drug trial showing the same "effect".

From my limited understanding of the topic I wasn't sure why these two were linked together in the Wired article, are they really that closely related?
i think they are part of a broad classification of propulsion, etc labelled Space drives? maybe that is why?

Title: Re: EM Drive Developments
Post by: Dunners73 on 07/31/2014 06:03 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237092#msg1237092">Quote from: Star One on 07/31/2014 05:45 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237091#msg1237091">Quote from: Dunners73 on 07/31/2014 05:44 PM</a>
Not sure this is related to the emdrive, think this is that Q thruster concept.
regardless, the abstract makes it sound more negative than positive.

"..Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article)."

Like the placebo in a drug trial showing the same "effect".

From my limited understanding of the topic I wasn't sure why these two were linked together in the Wired article, are they really that closely related?

I dont think they are very similar at all. - The Q thruster attempts to act upon underlying virtual particles to produce thrust without reaction mass while the EMdrive is trying a scheme of pumping microwaves into a sealed high Q (which equates to highly internally reflective) chamber, where one end is a different geometry to the other.

I suppose the results might be similar..  :-X

Title: Re: EM Drive Developments
Post by: john smith 19 on 07/31/2014 06:35 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237084#msg1237084">Quote from: Star One on 07/31/2014 05:13 PM</a>
Well it's appeared again.

http://www.wired.co.uk/news/archive/2014-07/31/nasa-validates-impossible-space-drive

This is the main link.

http://ntrs.nasa.gov/search.jsp?R=20140006052

Anyone notice Harold 'warp drive' White is one of the authors on this?

Reading the NASA papers (which is damm strange. It's more like an extended abstract. Is this due to be presented somewhere) shows it's nothing to do with the Chinese EM thruster work but is Sonny White's Quantum Vacuum Thruster

Here's the weird thing.

"within a stainless steel vacuum chamber with the door closed but at ambient atmospheric pressure. "
Personally I could see that 35-50 micro Newton (1x10^-6) being a microwave heating effect on the air.  :(

Show that with door on the chamber closed and the air pumped out makes the situation much more interesting.

Clearly the dear old Wired reports have conflated the QVT work with the EM thruster work, although I have to admit from a superficial reading the two seem similar.

Title: Re: EM Drive Developments
Post by: Star One on 07/31/2014 06:45 PM
Is it me or did that Wired article do this topic no favours, this stuff is right on the edge of technology and understanding and conflating things like that isn't helping?

Those more knowledgable than me is the NASA link helpful at all?
Title: Re: EM Drive Developments
Post by: NovaSilisko on 07/31/2014 06:56 PM
And so begins the flailing by the uninformed once again.
Title: Re: EM Drive Developments
Post by: Elmar Moelzer on 07/31/2014 07:12 PM

Quote
Manual frequency control was required throughout the test. Thrust was observed on both test
articles, even though one of the test articles was designed with the expectation that it would not produce
thrust. Specifically, one test article contained internal physical modifications that were designed to produce
thrust, while the other did not (with the latter being referred to as the “null” test article).
This looks like an issue to me that indicates a problem with their setup. Also, if I interpret their video on vimeo correctly, then their test setup has the problem that their power supply is in a different reference frame. From what I remember from previous discussions on the topic, that may distort the results:
http://vimeo.com/29837879

Title: Re: EM Drive Developments
Post by: Star One on 07/31/2014 09:19 PM
Sounds like more testing on this is in hand.

Dug up another article not sure if it adds anything much or not. Let's see if it survives further scrutiny to become something to keep eye on.

http://nextbigfuture.com/2014/07/renewed-hope-for-emdrive-with-nasa.html
Title: Re: EM Drive Developments
Post by: IslandPlaya on 07/31/2014 10:29 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237128#msg1237128">Quote from: Elmar Moelzer on 07/31/2014 07:12 PM</a>
Quote
Manual frequency control was required throughout the test. Thrust was observed on both test
articles, even though one of the test articles was designed with the expectation that it would not produce
thrust. Specifically, one test article contained internal physical modifications that were designed to produce
thrust, while the other did not (with the latter being referred to as the “null” test article).
This looks like an issue to me that indicates a problem with their setup. Also, if I interpret their video on vimeo correctly, then their test setup has the problem that their power supply is in a different reference frame. From what I remember from previous discussions on the topic, that may distort the results:
http://vimeo.com/29837879
Can you explain more about the power supply being in a different reference frame?
Surely it is not. It is at rest compared to the test device.

Title: Re: EM Drive Developments
Post by: Stormbringer on 07/31/2014 11:28 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237084#msg1237084">Quote from: Star One on 07/31/2014 05:13 PM</a>
Well it's appeared again.

http://www.wired.co.uk/news/archive/2014-07/31/nasa-validates-impossible-space-drive

This is the main link.

http://ntrs.nasa.gov/search.jsp?R=20140006052

Anyone notice Harold 'warp drive' White is one of the authors on this?

and Paul March. of Woodward Mach principle fame. :)

woohoo!

Title: Re: EM Drive Developments
Post by: Elmar Moelzer on 07/31/2014 11:52 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237212#msg1237212">Quote from: IslandPlaya on 07/31/2014 10:29 PM</a>
It is at rest compared to the test device.
Exactly, it is NOT being accelerated with the thruster.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/01/2014 12:37 AM
I wouldn't dream of posting here....
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/01/2014 01:23 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237256#msg1237256">Quote from: JohnFornaro on 08/01/2014 12:37 AM</a>
I wouldn't dream of posting here....
I can understand the skepticism...
However the experimenters are all NASA scientists.
What is the problem? are you a better scientist John F? Or do you think the authors should be stripped of their NASA posts?
Maybe we should calm down and investigate further?
Heavens!

Title: Re: EM Drive Developments
Post by: QuantumG on 08/01/2014 01:32 AM
Well, clearly, if they're NASA scientists they couldn't possibly be wrong.  ::)
Title: Re: EM Drive Developments
Post by: Robotbeat on 08/01/2014 01:37 AM
I happen to be a "NASA scientist" and a physicist, and I think it's (unprintable). I'm not saying that in any sort of official capacity. But really, extraordinary claims require extraordinary evidence. Or: "The first principle is that you must not fool yourself and you are the easiest person to fool." - Richard P. Feynman

Also, just because someone is skeptical of someone's results (or that they prove out to be wrong) doesn't mean you think they should be fired! If that was the standard, we'd all be fired at some point.
Title: Re: EM Drive Developments
Post by: Robotbeat on 08/01/2014 01:39 AM
It's important to realize this is a technical report, NOT a published journal article. If they got this published in, say, Physical Review Letters, then we've got something potentially interesting.
Title: Re: EM Drive Developments
Post by: ncb1397 on 08/01/2014 03:32 AM
Every generation has thought to themselves that they have figured out most everything there is to know or discover and each successive generation has been proven wrong. We must admit to ourselves that the unknown unknowns could be a vast expanse and relatively speaking, we are simply a couple short millenia and a very short distance past smashing rocks together to get fire.
Title: Re: EM Drive Developments
Post by: QuantumG on 08/01/2014 03:41 AM
Every generation has thought to themselves that the previous generation is a bunch of stick-in-the-muds who should have a more open mind, waxing philosophical about what might be, and then failed to produce anything new until they adopted a skeptical mindset.. thus becoming the next generation of stick-in-the-muds.

We're not skeptical because we think we know it all.. we're skeptical because it works.

Title: Re: EM Drive Developments
Post by: Robotbeat on 08/01/2014 03:42 AM
Sure. But Occam's Razor and Bayesian statistics (there's a strong prior, here) suggests the most likely explanation is some sort of screw up. Same deal with that ostensibly faster than light neutrino thing of yesteryear.
Title: Re: EM Drive Developments
Post by: sanman on 08/01/2014 04:21 AM
Is NASA the only one who can test things? Surely this is a matter for major laboratories and university research teams to take a look at - even if only to issue a definitive disproof.



Title: Re: EM Drive Developments
Post by: CriX on 08/01/2014 05:05 AM
I know very little about this, but it doesn't seem to claim free energy.  Sonny describes the "q thruster" as being essentially like a water propeller, except pushing against vacuum virtual particles.... which sounds plausible... to these foolish ears.  It's definitely disconcerting that even their null device produced "thrust" though. 
Title: Re: EM Drive Developments
Post by: Robotbeat on 08/01/2014 05:22 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237326#msg1237326">Quote from: CriX on 08/01/2014 05:05 AM</a>
I know very little about this, but it doesn't seem to claim free energy.  Sonny describes the "q thruster" as being essentially like a water propeller, except pushing against vacuum virtual particles.... which sounds plausible... to these foolish ears.  It's definitely disconcerting that even their null device produced "thrust" though.
The end result for these propellantless propulsion devices is free energy, though.

Title: Re: EM Drive Developments
Post by: MP99 on 08/01/2014 06:04 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237212#msg1237212">Quote from: IslandPlaya on 07/31/2014 10:29 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237128#msg1237128">Quote from: Elmar Moelzer on 07/31/2014 07:12 PM</a>
Quote
Manual frequency control was required throughout the test. Thrust was observed on both test
articles, even though one of the test articles was designed with the expectation that it would not produce
thrust. Specifically, one test article contained internal physical modifications that were designed to produce
thrust, while the other did not (with the latter being referred to as the “null” test article).
This looks like an issue to me that indicates a problem with their setup. Also, if I interpret their video on vimeo correctly, then their test setup has the problem that their power supply is in a different reference frame. From what I remember from previous discussions on the topic, that may distort the results:
http://vimeo.com/29837879
Can you explain more about the power supply being in a different reference frame?
Surely it is not. It is at rest compared to the test device.
If the PSU experiences an equal but opposite thrust while bolted down to the desk, then no one would notice, but it would invalidate it as a thruster.

Cheers, Martin

Title: Re: EM Drive Developments
Post by: Star One on 08/01/2014 07:57 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237316#msg1237316">Quote from: sanman on 08/01/2014 04:21 AM</a>
Is NASA the only one who can test things? Surely this is a matter for major laboratories and university research teams to take a look at - even if only to issue a definitive disproof.

I assume because the scientific establishment don't want to know for whatever reason, which too me knowing the history of how things can come from left field is perhaps not so good? From a theoretical viewpoint it would be quite interesting if there did turn out to be something in it because by the looks of it would require some re-thinking of certain areas of theory.

Title: Re: EM Drive Developments
Post by: kerlc on 08/01/2014 08:41 AM
Could it be possible that this is merely another open system, like solar sails?
Title: Re: EM Drive Developments
Post by: Lee Jay on 08/01/2014 08:57 AM
Since this was done in air, could it be this effect, which is real but unremarkable?

http://youtu.be/2uD9wtq29h8
Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/01/2014 09:04 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237352#msg1237352">Quote from: Star One on 08/01/2014 07:57 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237316#msg1237316">Quote from: sanman on 08/01/2014 04:21 AM</a>
Is NASA the only one who can test things? Surely this is a matter for major laboratories and university research teams to take a look at - even if only to issue a definitive disproof.

I assume because the scientific establishment don't want to know for whatever reason, which too me knowing the history of how things can come from left field is perhaps not so good? From a theoretical viewpoint it would be quite interesting if there did turn out to be something in it because by the looks of it would require some re-thinking of certain areas of theory.

Right, the "scientific establishment" don't want to know.  Because we all know the "scientific establishment" is a hive mind that makes collective decisions.  It's definitely not hundreds of thousands of individuals who have a love of knowledge and desire to find out about the world we live in.  It can't possibly be that those hundreds of thousands of individuals in dozens of countries are free to do whatever research they want to.

And it's just not possible that reputable scientists aren't spending their time on this because they honestly believe that it would be a waste of their time, and that they have the education, experience, and intelligence to tell science from pseudo-science.

Title: Re: EM Drive Developments
Post by: Star One on 08/01/2014 09:12 AM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237367#msg1237367">Quote from: ChrisWilson68 on 08/01/2014 09:04 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237352#msg1237352">Quote from: Star One on 08/01/2014 07:57 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237316#msg1237316">Quote from: sanman on 08/01/2014 04:21 AM</a>
Is NASA the only one who can test things? Surely this is a matter for major laboratories and university research teams to take a look at - even if only to issue a definitive disproof.

I assume because the scientific establishment don't want to know for whatever reason, which too me knowing the history of how things can come from left field is perhaps not so good? From a theoretical viewpoint it would be quite interesting if there did turn out to be something in it because by the looks of it would require some re-thinking of certain areas of theory.

Right, the "scientific establishment" don't want to know.  Because we all know the "scientific establishment" is a hive mind that makes collective decisions.  It's definitely not hundreds of thousands of individuals who have a love of knowledge and desire to find out about the world we live in.  It can't possibly be that those hundreds of thousands of individuals in dozens of countries are free to do whatever research they want to.

And it's just not possible that reputable scientists aren't spending their time on this because they honestly believe that it would be a waste of their time, and that they have the education, experience, and intelligence to tell science from pseudo-science.

Yeah the same scientific establishment that spent so long saying oh no there is nothing like plate tectonics, the Big Bang or lead in fuel actually causing health effects. I bet you could come up with plenty of examples usually ending with whoops we were wrong & in fact the mavericks were right.

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/01/2014 09:57 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237371#msg1237371">Quote from: Star One on 08/01/2014 09:12 AM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237367#msg1237367">Quote from: ChrisWilson68 on 08/01/2014 09:04 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237352#msg1237352">Quote from: Star One on 08/01/2014 07:57 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237316#msg1237316">Quote from: sanman on 08/01/2014 04:21 AM</a>
Is NASA the only one who can test things? Surely this is a matter for major laboratories and university research teams to take a look at - even if only to issue a definitive disproof.

I assume because the scientific establishment don't want to know for whatever reason, which too me knowing the history of how things can come from left field is perhaps not so good? From a theoretical viewpoint it would be quite interesting if there did turn out to be something in it because by the looks of it would require some re-thinking of certain areas of theory.

Right, the "scientific establishment" don't want to know.  Because we all know the "scientific establishment" is a hive mind that makes collective decisions.  It's definitely not hundreds of thousands of individuals who have a love of knowledge and desire to find out about the world we live in.  It can't possibly be that those hundreds of thousands of individuals in dozens of countries are free to do whatever research they want to.

And it's just not possible that reputable scientists aren't spending their time on this because they honestly believe that it would be a waste of their time, and that they have the education, experience, and intelligence to tell science from pseudo-science.

Yeah the same scientific establishment that spent so long saying oh no there is nothing like plate tectonics, the Big Bang or lead in fuel actually causing health effects. I bet you could come up with plenty of examples usually ending with whoops we were wrong & in fact the mavericks were right.

Those examples you gave are all cases where there was inconclusive evidence at the time and robust scientific debate.  None of it was considered pseudo-science.  It wasn't remotely like the scientific attitude toward the EmDrive and Sonny White's theories.

Plate tectonics, the Big Bang theory, and health effects of lead were all cases of scientific theory evolving to encompass new evidence.  The EmDrive and White's theories are the opposite -- they put the theory first and then go looking for evidence afterwards.  In both cases, the theories claim to be consequences of existing theories in physics, but reputable physicists say that in fact they come from misunderstandings of current theories.

Title: Re: EM Drive Developments
Post by: knowles2 on 08/01/2014 10:14 AM
Well now have three separate teams all reporting positive results with two different devices, to me it seem like there something here that need further exploration.
Title: Re: EM Drive Developments
Post by: Star One on 08/01/2014 10:51 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237378#msg1237378">Quote from: knowles2 on 08/01/2014 10:14 AM</a>
Well now have three separate teams all reporting positive results with two different devices, to me it seem like there something here that need further exploration.

Precisely. I am pretty certain that smart people like those from NASA here wouldn't have been persuaded to waste both their valuable time and effort unless they thought it was worth looking into. It's more than possible (in fact at this time it's likely) there is nothing in it but they are at least looking into it even if it ends up disproving it the effort is still a worthwhile one in my view. Even if by some very remote chance it's correct wouldn't we all be kicking ourselves if we had missed that opportunity?

999/1000 these things prove to be wrong or an error somewhere along the line, it's the 1 that makes them interesting.:)

Title: Re: EM Drive Developments
Post by: ncb1397 on 08/01/2014 04:19 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237297#msg1237297">Quote from: QuantumG on 08/01/2014 03:41 AM</a>
Every generation has thought to themselves that the previous generation is a bunch of stick-in-the-muds who should have a more open mind, waxing philosophical about what might be, and then failed to produce anything new until they adopted a skeptical mindset.. thus becoming the next generation of stick-in-the-muds.

We're not skeptical because we think we know it all.. we're skeptical because it works.

Skepticism cuts both ways - established science and new science. There are so many gaping holes in astrophysics, you should be as skeptical of the established view of how things work as you are of something that doesn't fit the current view. Scientists have blind spots. All those scientists before Einstien had no problem with light traveling at the speed of light from every reference frame even though the only logical result of applying their rules would be an incoherent universe.  Applying current physics to the universe yields all sorts of stop-gap measures like dark energy and dark matter.

Anyways, skepticism and an open mind are not opposing things. In fact, the opposite of an open mind is a closed mind, and a closed mind is not skeptical of its own viewpoint and therefore is not practicing true skepticism.

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/01/2014 06:10 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237378#msg1237378">Quote from: knowles2 on 08/01/2014 10:14 AM</a>
Well now have three separate teams all reporting positive results with two different devices, to me it seem like there something here that need further exploration.

The EmDrive has nothing to do with Sonny White's device, so it makes no sense to lump them together.

And in one of the tests both the test device and the control device showed thrust, indicating the measured effect was a result of error in the test setup, not success by the device.

So, not a lot of indication of anything interesting going on.

Title: Re: EM Drive Developments
Post by: AlanSE on 08/01/2014 06:41 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237543#msg1237543">Quote from: ChrisWilson68 on 08/01/2014 06:10 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237378#msg1237378">Quote from: knowles2 on 08/01/2014 10:14 AM</a>
Well now have three separate teams all reporting positive results with two different devices, to me it seem like there something here that need further exploration.

The EmDrive has nothing to do with Sonny White's device, so it makes no sense to lump them together.

And in one of the tests both the test device and the control device showed thrust, indicating the measured effect was a result of error in the test setup, not success by the device.

So, not a lot of indication of anything interesting going on.

It's hard to tell what's going on in this comment. I think you might have in mind one of Dr. White's other proposals, for warp drives or something. His more recent publication is at least somewhat relevant:

http://ntrs.nasa.gov/search.jsp?R=20140006052

Here, he writes about "momentum transfer" via virtual particles of some plasma or something. But the use of the word "transfer" itself seems to indicate that they have no intention to sell this as a reactionless drive, making it different from the crackpots out there. Nonetheless, they are publishing about producing a force due to some bizarre quantum field theory effect. I don't even believe this, but it's worth some scientific articles until people can pin down exactly what the reproducibility and scale of the effect is. It would be overly-generous to suggest that the EmDrive was measuring this effect. They did both look at "anomalous thrust", but of completely different kinds.

Title: Re: EM Drive Developments
Post by: scienceguy on 08/01/2014 06:51 PM
Don't the vacuum fluctuations only exist for 10^-44 s each (the Planck time)? How can you possibly transfer enough momentum to anything in 10^-44 s?
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/01/2014 06:58 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237365#msg1237365">Quote from: Lee Jay on 08/01/2014 08:57 AM</a>
Since this was done in air, could it be this effect, which is real but unremarkable?

http://youtu.be/2uD9wtq29h8

maybe but unless i am recalling incorrectly Dr Woodward's version of this (which is different in execution than this, but same basic class of idea) is tested in a vacuum chamber with the atmosphere evacuated to exclude ion related effects.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/01/2014 07:03 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237562#msg1237562">Quote from: scienceguy on 08/01/2014 06:51 PM</a>
Don't the vacuum fluctuations only exist for 10^-44 s each (the Planck time)? How can you possibly transfer enough momentum to anything in 10^-44 s?

i'm not a scientist and I may get jumped on for saying this but isn't it true that in the QED math there are particles and things smaller than the plank limit? They are discarded as mathematical artifacts but what if they aren't? that's basically part of Dr Woodward's thinking on how to get something (negative energy or exposing the naked rest mass) out of mach's principle.

i cannot elaborate beyond that because i do not know the theory or the math but am going by one of Dr Woodward's videos. so don't ask me for more. but maybe someone here can fill it out further?

Title: Re: EM Drive Developments
Post by: Robotbeat on 08/01/2014 07:25 PM
If the null device also produced measurable thrust, then the effect is an artifact, to high confidence. This is the reason for having a null sample. It helps makes sure you're not fooling yourself.
Title: Re: EM Drive Developments
Post by: Star One on 08/01/2014 07:35 PM
This is the most lucid article I've read on this and at least it doesn't muddle the two up and it contains some additional comment. Half the problem with this story seems to be the muddled reporting of it.

http://www.popsci.com/article/technology/fuel-less-space-drive-may-actually-work-says-nasa?dom=PSC&loc=recent&lnk=5&con=fuelless-space-drive-may-actually-work-says-nasa

It clearly states the device tested was not White's device but it was similar.

It also states they are looking for the results to be peer reviewed.
Title: Re: EM Drive Developments
Post by: Star One on 08/01/2014 08:23 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237027#msg1237027">Quote from: IslandPlaya on 07/31/2014 03:04 PM</a>
New paper describing encouraging results from the testing of an 'EM-drive' like device.
http://ntrs.nasa.gov/search.jsp?R=20140006052 (http://ntrs.nasa.gov/search.jsp?R=20140006052)
Hope it stands up to further scrutiny. Could be a real game changer!

Hello we've now got two threads on this.

I used this existing thread from last year?

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/01/2014 08:27 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237604#msg1237604">Quote from: Star One on 08/01/2014 08:23 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237027#msg1237027">Quote from: IslandPlaya on 07/31/2014 03:04 PM</a>
New paper describing encouraging results from the testing of an 'EM-drive' like device.
http://ntrs.nasa.gov/search.jsp?R=20140006052 (http://ntrs.nasa.gov/search.jsp?R=20140006052)
Hope it stands up to further scrutiny. Could be a real game changer!

Hello we've now got two threads on this.

I used this existing thread from last year?
Yes. I did a search before I created a new topic but somehow missed the EM drive thread. Doh!
Not sure what to do about it now... Apologies.

Title: Re: EM Drive Developments
Post by: iamlucky13 on 08/01/2014 08:33 PM

Reading the abstract, Crix seems to be on the right track about quantum mechanics, but I don't know enough to speculate from there what would be happening:

Quote
Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma.

However, it appears to me that there is a problem being ignored by the media that are reporting on this:

Quote
Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article)

Since one experiment that should NOT have detected thrust did detect thrust, that calls into question whether there was a mistake in the test setup. Since the test chamber was not at a vacuum, I'd call that a very likely source for error. A more promising possibility is it detects thrust in configurations they didn't expect, but the simpler explanation is the former.

Title: Re: EM Drive Developments
Post by: sghill on 08/01/2014 08:54 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237611#msg1237611">Quote from: iamlucky13 on 08/01/2014 08:33 PM</a>

Quote
Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article)

Since one experiment that should NOT have detected thrust did detect thrust, that calls into question whether there was a mistake in the test setup. Since the test chamber was not at a vacuum, I'd call that a very likely source for error. A more promising possibility is it detects thrust in configurations they didn't expect, but the simpler explanation is the former.

That was exactly my thought too.

Title: Re: EM Drive Developments
Post by: iamlucky13 on 08/01/2014 08:58 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237328#msg1237328">Quote from: Robotbeat on 08/01/2014 05:22 AM</a>
The end result for these propellantless propulsion devices is free energy, though.

No, it wouldn't be free energy. You need energy to generate the RF. What it avoids is needing classical mass to transfer momentum.  An electric car also requires energy but no propellant, but it achieves momentum transfer by reacting against the ground.

Conservation of momentum is the hangup.

An affect we know about is radiation pressure: photons have momentum. Hence why a solar sail can work even without a solar wind.

As far as I know, any antenna that is not omnidirectional would produce a small amount of net thrust. But incredibly small - photons have momentum, but not a lot of it.

According to Wikipedia, a solar sail at 1 AU that is 800 meters x 800 meters, would generate about 5N of thrust, or about 55 times what the ion thrusters on the Dawn spacecraft produce, and about 100,000 times as much as the test appears to have measured.

If my math is right based on that, an effectively uni-directional microwave beam of ~17 kW would produce the ~50microNewton's of force they measured.

But hopefully they are aware of radiation pressure and would be accounting for whatever their actual power level is. Otherwise, I don't know why they would invoke vacuum pressure.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/01/2014 09:04 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237582#msg1237582">Quote from: Star One on 08/01/2014 07:35 PM</a>
This is the most lucid article I've read on this and at least it doesn't muddle the two up and it contains some additional comment. Half the problem with this story seems to be the muddled reporting of it.

http://www.popsci.com/article/technology/fuel-less-space-drive-may-actually-work-says-nasa?dom=PSC&loc=recent&lnk=5&con=fuelless-space-drive-may-actually-work-says-nasa

It clearly states the device tested was not White's device but it was similar.

It also states they are looking for the results to be peer reviewed.

awesome! Thanks for the link :)

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/01/2014 09:06 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237608#msg1237608">Quote from: IslandPlaya on 08/01/2014 08:27 PM</a>



Yes. I did a search before I created a new topic but somehow missed the EM drive thread. Doh!
Not sure what to do about it now... Apologies.
It's a thread. the server DB will not self destruct or lag because of it. :) besides normally Forum moderators have authorization to merge threads if it really bugs anyone. i dunno if that is delegated to them here or if it's admin level. it would put extra work on the admins if it hasn't been delegated to moderators though.

Title: Re: EM Drive Developments
Post by: daveklingler on 08/01/2014 09:08 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237611#msg1237611">Quote from: iamlucky13 on 08/01/2014 08:33 PM</a>
Reading the abstract, Crix seems to be on the right track about quantum mechanics, but I don't know enough to speculate from there what would be happening:

Quote
Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma.

However, it appears to me that there is a problem being ignored by the media that are reporting on this:

Quote
Thrust was observed on both test articles, even though one of the test articles was designed with the expectation that it would not produce thrust. Specifically, one test article contained internal physical modifications that were designed to produce thrust, while the other did not (with the latter being referred to as the "null" test article)

Since one experiment that should NOT have detected thrust did detect thrust, that calls into question whether there was a mistake in the test setup. Since the test chamber was not at a vacuum, I'd call that a very likely source for error. A more promising possibility is it detects thrust in configurations they didn't expect, but the simpler explanation is the former.

Guido Fetta designed one of the test articles to test his theory regarding why the thruster worked.  If his theory was correct, the null test article should not have produced thrust.  Essentially the test invalidated Fetta's theory, but not the test or the test article.  Given that the test took place in August 2013, Brady et al have had plenty of time to determine whether there was a problem in the test jig. 

It would appear that if there is a systematic problem, it's exceedingly subtle.  Four parties (Shawyer, Yang, Fretta, NASA Eagleworks) have found thrust.  As the Eagleworks paper says, "Future test plans include independent verification and validation at other test facilities." 

Title: Re: EM Drive Developments
Post by: Nathan on 08/01/2014 09:22 PM
The nasa link is to an abstract only- it says abstract only available. One presumes the rest of the paper will be available after peer review.
Glad to see this has been investigated.
Title: Re: EM Drive Developments
Post by: GusTurbo on 08/01/2014 09:40 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237576#msg1237576">Quote from: Robotbeat on 08/01/2014 07:25 PM</a>
If the null device also produced measurable thrust, then the effect is an artifact, to high confidence. This is the reason for having a null sample. It helps makes sure you're not fooling yourself.

That seems to be the element that most people are missing when they hear about this. The internet is teeming with credulousness about this, and it's a bit alarming.

I think people would do well to have a little skepticism and not view this as being "NASA-approved," just because it has been tested by NASA. For a taste of the reporting on this:

http://sploid.gizmodo.com/nasa-reveals-new-impossible-engine-can-change-space-t-1614549987

Title: Re: EM Drive Developments
Post by: Star One on 08/01/2014 10:35 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237629#msg1237629">Quote from: Nathan on 08/01/2014 09:22 PM</a>
The nasa link is to an abstract only- it says abstract only available. One presumes the rest of the paper will be available after peer review.
Glad to see this has been investigated.

That would be best. The reporting on this & reaction online in places has been atrocious, it reminds me of the reporting and reaction to both the faster than light neutrinos & ancient gravity waves. The former was an error and the latter has taken a terrible battering under peer review. I'll be interested to see how this gets on with peer review.

Title: Re: EM Drive Developments
Post by: Cherokee43v6 on 08/01/2014 10:38 PM
em-drives, ion engines, VASIMIR, Alcubrier... seem's we have a bazillion ways to go fast on very little fuel once we are up there...  But we still have to deal with the rocket equation to get there in the first place.  I'm waiting to see a /real/ game-changer come along... a provable means of getting out of the gravity well that beats rockets.

Sadly, we are rather lacking in acceptable options there still.
Title: Re: EM Drive Developments
Post by: Star One on 08/01/2014 10:40 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237651#msg1237651">Quote from: Cherokee43v6 on 08/01/2014 10:38 PM</a>
em-drives, ion engines, VASIMIR, Alcubrier... seem's we have a bazillion ways to go fast on very little fuel once we are up there...  But we still have to deal with the rocket equation to get there in the first place.  I'm waiting to see a /real/ game-changer come along... a provable means of getting out of the gravity well that beats rockets.

Sadly, we are rather lacking in acceptable options there still.

I think even if the EM thruster actually worked as advertised that it's my understanding you would still need a jet engine for an aircraft or rocket for a spacecraft to get off the ground in the first place.

Title: Re: EM Drive Developments
Post by: Cherokee43v6 on 08/01/2014 10:41 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237652#msg1237652">Quote from: Star One on 08/01/2014 10:40 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237651#msg1237651">Quote from: Cherokee43v6 on 08/01/2014 10:38 PM</a>
em-drives, ion engines, VASIMIR, Alcubrier... seem's we have a bazillion ways to go fast on very little fuel once we are up there...  But we still have to deal with the rocket equation to get there in the first place.  I'm waiting to see a /real/ game-changer come along... a provable means of getting out of the gravity well that beats rockets.

Sadly, we are rather lacking in acceptable options there still.

I think even if the EM thruster actually worked as advertised that it's my understanding you would still need a jet engine for an aircraft or rocket for a spacecraft to get off the ground in the first place.

Exactly my point.

Title: Re: EM Drive Developments
Post by: Star One on 08/01/2014 10:43 PM
Can I ask as a layman is part of the problem here with anyone analysing this that only an abstract has been published, no doubt because they are waiting peer review?
Title: Re: EM Drive Developments
Post by: CriX on 08/01/2014 11:40 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237328#msg1237328">Quote from: Robotbeat on 08/01/2014 05:22 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237326#msg1237326">Quote from: CriX on 08/01/2014 05:05 AM</a>
I know very little about this, but it doesn't seem to claim free energy.  Sonny describes the "q thruster" as being essentially like a water propeller, except pushing against vacuum virtual particles.... which sounds plausible... to these foolish ears.  It's definitely disconcerting that even their null device produced "thrust" though.
The end result for these propellantless propulsion devices is free energy, though.

Damnit!  I really want to believe that this is possible.  It seems "fair" that we should be able to spend 2 MegaWatts and get some momentum in exchange.  I hope you've not adequately looked into this.

Title: Re: EM Drive Developments
Post by: brokndodge on 08/02/2014 12:18 AM
I'll be interested to see what changes they made to the "null" device and why they believed that those changes would prevent it from producing thrust.
Title: Re: EM Drive Developments
Post by: cuddihy on 08/02/2014 05:18 AM
Chris robotbeat's point only holds if you start from the assumption that it can't work. Once you start there, you can then draw your system box in such a way that it excludes the claimed source of momentum/energy. QED you now can call it  'free' energy.
Of course, the argument is a tautology, and it's a way of dismissing the claims on their face by refusing the initial assumptions, but it comes up any time Woodward or White's work are being discussed.

That said, the paper linked clearly says the device constructed to not get results got results anyway, so QED the resonant cavity theory is falsified by this experiment... So not sure why anyone's excited...
Title: Re: EM Drive Developments
Post by: Robotbeat on 08/02/2014 05:23 AM
You could use this device to harvest energy from the Universe one way or anoter. But anyway, in my opinion it's at least as bad to violate conservation of momentum.
Title: Re: EM Drive Developments
Post by: Optimistic Brian on 08/02/2014 05:53 AM
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/02/2014 06:32 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237816#msg1237816">Quote from: Optimistic Brian on 08/02/2014 05:53 AM</a>
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.

it is my opinion that because there are at least 5 instances of this general class of scheme that have had positive results that there is something to it.

1. Woodward's version is tested on a torsion balance in a vacuum chamber with atmosphere evacuated. he has shown thrust.
2. This present Shafley resonant cavity thing.
3. the Chinese version of this which was developed from number 2 above because he could not get anyone else interested. they report thiers is ten times as powerful at 100 to 500 mN.
4. Dr Whites QVPT. he has positive results too.
5. the Egyptian Girl's version of this thing. hers uses the dynamic casimir effect. hers is being considered for satellite maneuver and station keeping.

Title: Re: EM Drive Developments
Post by: KelvinZero on 08/02/2014 07:49 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237816#msg1237816">Quote from: Optimistic Brian on 08/02/2014 05:53 AM</a>
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

The energy may in fact come from somewhere else. That is fine. What I just do not understand is proponents not admitting to themselves how fundamental a gift this would be.

Alternatively, perhaps this effect is somehow tied to a local reference frame, like pushing against water or solar wind. This would make it far less effective but still would be a vast improvement over the rocket equation. I dont know what would define that frame since I haven't seen any claim that this is the case.

Not investigating these simple aspects with awesome consequences is like not taking your own claim seriously. Similarly with anyone proposing FTL without investigating how the paradoxes would be resolved. If you cannot describe these cases then you cannot describe what you are claiming to have produced.

Title: Re: EM Drive Developments
Post by: QuantumG on 08/02/2014 08:05 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237829#msg1237829">Quote from: KelvinZero on 08/02/2014 07:49 AM</a>
(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.

Maybe it doesn't, ya know.

Title: Re: EM Drive Developments
Post by: KelvinZero on 08/02/2014 08:27 AM
Perhaps I should have qualified that.. :)
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 10:21 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237829#msg1237829">Quote from: KelvinZero on 08/02/2014 07:49 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237816#msg1237816">Quote from: Optimistic Brian on 08/02/2014 05:53 AM</a>
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

The energy may in fact come from somewhere else. That is fine. What I just do not understand is proponents not admitting to themselves how fundamental a gift this would be.

Alternatively, perhaps this effect is somehow tied to a local reference frame, like pushing against water or solar wind. This would make it far less effective but still would be a vast improvement over the rocket equation. I dont know what would define that frame since I haven't seen any claim that this is the case.

Not investigating these simple aspects with awesome consequences is like not taking your own claim seriously. Similarly with anyone proposing FTL without investigating how the paradoxes would be resolved. If you cannot describe these cases then you cannot describe what you are claiming to have produced.
*If* the effect is real I would speculate (as I have done before in other threads) that the kinetic energy your device gains during operation is always less than the energy input into the device.
This ties the effect to a local reference frame as you state. I would further speculate that this reference frame is the CMB rest frame.
See http://physics.stackexchange.com/questions/25928/is-the-cmb-rest-frame-special-where-does-it-come-from (http://physics.stackexchange.com/questions/25928/is-the-cmb-rest-frame-special-where-does-it-come-from) for a discussion...
Now this is a lot of handwaving and I don't know what mechanism would be involved, but it would address the free-energy objection.
I think  ;)

Title: Re: EM Drive Developments
Post by: KelvinZero on 08/02/2014 10:37 AM
Heh.. thats quite cool.. and with a 400km/s relative velocity we should be gaining energy, not expending it at least to begin with.. Just put on the brakes and end up shooting from our solar system at a pretty fair clip!

http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation#CMBR_dipole_anisotropy

what is in exactly the opposite direction of in the direction of "galactic longitude l = 263.99±0.14°, b = 48.26±0.03°" anyway?
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 10:53 AM
Not sure if you missed the /sarc tags in the first part of your post.  ::)
"Putting the brakes" on to be at rest wrt the CMB would take the same amount of energy (with caveats due to special relativity) as would accelerating to 400km/s in any direction.
Title: Re: EM Drive Developments
Post by: mboeller on 08/02/2014 11:35 AM
first device:  www.emdrive.com
second device:  www.cannae.com

good discussions (2 threads) can be found here, including a lot of links:
http://www.talk-polywell.org/bb/viewforum.php?f=10&sid=3b93a639a0baff9ff89938b7b90beebd
Title: Re: EM Drive Developments
Post by: KelvinZero on 08/02/2014 11:39 AM
No sarcasm. I don't understand the method in this thread and as far as I know it has not mentioned pushing on a particular frame, but I am pretty sure you would have to gain energy, or it is a mystery where that energy is going. In any case the important thing is that the amount of energy expended goes up proportional to the square of your current velocity relative to this medium.. otherwise, free energy.

The obvious example is movement in air with a propeller. This is an example of where pushing against some medium is sort of like propellantless propulsion and it would obey the classical velocity squared rule. However you would not have to expend any energy just to come to rest with respect to the air, in fact you could gain energy while doing so. For example you could allow the wind to turn the propeller, generating energy like a windmill and creating drag until your velocity matched that of your surroundings.
Title: Re: EM Drive Developments
Post by: CapitalistOppressor on 08/02/2014 12:05 PM
The abstract just doesn't give enough information.

That said, there appear to have been three items tested on the rig, including an inert object and two test articles, one of which was modified so as not to produce thrust.

The fact that the modified one still produced thrust is a problem.  But we don't know the modifications.  It seems apparent that they were feeding energy into the modified test article.  Otherwise they wouldn't have needed an inert object.

As it is they are saying the inert object did not do anything, while both the engine and modified engine achieved measurable thrust. 

This would maybe make sense if the modifications were to the shape of the container, and were intended to test the theoretical predictions by the inventor. 

There is some supposed theory from the US inventor Guiddo Fetta underlying his Cannae Drive which seem to point to the shape of the container affecting the thrust.  I could see them modifying the shape of the container to test that hypothesis.  If flooding the modified container with microwaves also produced thrust it would mean the shape does not affect the thrust and you have bad theory.  But that doesn't necessarily mean you don't have an effect.

Frankly the seeming violation of conservation of momentum makes it extremely likely that there is an experimental problem.  The fact that the modified engine still produced thrust is a minor issue in comparison.


Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 12:38 PM
Fair comment.
I guess we will have to just see what turns up if they continue to refine the experiments.
Maybe a slim chance of a real, usable effect, but the payoff would be so enormous that it must be worth a fair bit of time, money and effort to either put this to bed for good or confirm it to a high degree of confidence.
Title: Re: EM Drive Developments
Post by: Silversheep2011 on 08/02/2014 01:24 PM
The Wright brothers,
Were two American brothers, inventors, and aviation pioneers who are credited with inventing and building the world's first successful airplane and making the first controlled, powered and sustained heavier-than-air human flight, on December 17, 1903

Prior to that, Some would say that, "Heaver than air was consider impossible". Now it's  considered  common scientific fact...

I think we often have that same Pre-1903 mindset.
 I debated this last year with a 'Doctor of Engineering' at work.
  We disagree when it comes to innovation.
     He says "Impossible is always impossible'

I say:   
 
  "Possible may lead to Possible"         [ if some design works,-  it might work in another application]
 "Impossible might just be Possible "   [ see video 'Fernman Chaser' below -if this rule is used]
  "Possible becomes Impossible"          [Often when we think -of the work and effort involved- a mindset]

So the more we Test, the more we Validate, then the more the,  'Impossible becomes True.'

My acknowledgement to the Wright brothers...

 
Title: Re: EM Drive Developments
Post by: RonM on 08/02/2014 02:07 PM
The first line in the abstract of the technical report is "This paper describes the eight-day August 2013 test campaign designed to investigate and demonstrate viability of using classical magnetoplasmadynamics to obtain a propulsive momentum transfer via the quantum vacuum virtual plasma."

Who knows if this will work, but it is not some magic inertial-less drive that can lead to free energy or perpetual motion. It is an attempt to interact with virtual particles like an electromagnet would interact with an electric field.
Title: Re: EM Drive Developments
Post by: GreenShrike on 08/02/2014 02:21 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237809#msg1237809">Quote from: cuddihy on 08/02/2014 05:18 AM</a>
That said, the paper linked clearly says the device constructed to not get results got results anyway, so QED the resonant cavity theory is falsified by this experiment...

That just means the theory at best requires modification and at worst is a barrel of raw sewage that needs to be dumped and reconsidered entirely.

However, that's how science works -- you experiment to prove or disprove the hypothesis, and when the experiment shows the hypothesis needs to be adjusted, you adjust it and redo the experiment.


<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237809#msg1237809">Quote from: cuddihy on 08/02/2014 05:18 AM</a>
So not sure why anyone's excited...

Because anomalous thrust was measured. *Something* caused it. Probably instrument error or an unaccounted for external influence, true, but they still measured it. And until the thrust is explained, there remains the possibility that something unexplained is going on -- and unexplained physics is exciting.

I eagerly await the peer review of the article.

Title: Re: EM Drive Developments
Post by: KelvinZero on 08/02/2014 03:03 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237898#msg1237898">Quote from: RonM on 08/02/2014 02:07 PM</a>
The first line in the abstract of the technical report is "This paper describes the eight-day August 2013 test campaign designed to investigate and demonstrate viability of using classical magnetoplasmadynamics to obtain a propulsive momentum transfer via the quantum vacuum virtual plasma."

Who knows if this will work, but it is not some magic inertial-less drive that can lead to free energy or perpetual motion. It is an attempt to interact with virtual particles like an electromagnet would interact with an electric field.
Thats fine, so long as it is understood that if this experiment behaves the same regardless of inertial frame (usually considered a positive for a theory) then it will provide free energy.

Hey! come to think of it, that air example I made above implies we could also get energy for free from the CMB case. In that case it would merely be the good old energy we used to exploit all the time in sailing ships, where you have water and wind moving with different average velocities. We could exploit the difference between the CMB frame and the interstellar medium (say with a minimagnetosphere) or more immediately we could produce energy from a slight drag on the CMB frame, gradually bringing the speed of the planet (and through the slight force of gravity, our sun) to rest WRT to the CMB. The mass of the sun and 400km/s is a massive store of energy.

Title: Re: EM Drive Developments
Post by: Scylla on 08/02/2014 03:19 PM
Why do I keep seeing reference to "free energy". Am I misunderstanding the meaning of it's use in theses posts?

Even if the device works, you have to introduce energy (microwaves) to make it work.

TANSTAAFL
Title: Re: EM Drive Developments
Post by: Prober on 08/02/2014 03:55 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237882#msg1237882">Quote from: IslandPlaya on 08/02/2014 12:38 PM</a>
Fair comment.
I guess we will have to just see what turns up if they continue to refine the experiments.
Maybe a slim chance of a real, usable effect, but the payoff would be so enormous that it must be worth a fair bit of time, money and effort to either put this to bed for good or confirm it to a high degree of confidence.

agreed, how bout we package up a working unit and move it up to the ISS for a real test.  We don't have time to waste when it comes to using the LEO Space Lab that's available now.

Title: Re: EM Drive Developments
Post by: cuddihy on 08/02/2014 03:56 PM
What the free energy folks are saying is that if you assume a) that the device provides thrust at a constant or linear rate based on energy input and b) that this assumption holds with no changes at different velocites then c) since kinetetic energy increases at the rate of velocity squared, you are getting an exponential increase in KE for a linear or constant input in Electrical energy. Ie, "free" energy is the delta between KE out and EE in.

What this thesis ignores is that none of these theories extend how their devices would function as velocity increases. Whether they interact with virtual particles or far-off active matter, none of the theories speculate about how "coupling" occurs. So the thesis is pointing out an incongruity in an extension of the theory being tested that goes well beyond what the theory currently proposes...it's a scientific strawman attack.
Title: Re: EM Drive Developments
Post by: RonM on 08/02/2014 04:10 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237909#msg1237909">Quote from: KelvinZero on 08/02/2014 03:03 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237898#msg1237898">Quote from: RonM on 08/02/2014 02:07 PM</a>
The first line in the abstract of the technical report is "This paper describes the eight-day August 2013 test campaign designed to investigate and demonstrate viability of using classical magnetoplasmadynamics to obtain a propulsive momentum transfer via the quantum vacuum virtual plasma."

Who knows if this will work, but it is not some magic inertial-less drive that can lead to free energy or perpetual motion. It is an attempt to interact with virtual particles like an electromagnet would interact with an electric field.
Thats fine, so long as it is understood that if this experiment behaves the same regardless of inertial frame (usually considered a positive for a theory) then it will provide free energy.

Hey! come to think of it, that air example I made above implies we could also get energy for free from the CMB case. In that case it would merely be the good old energy we used to exploit all the time in sailing ships, where you have water and wind moving with different average velocities. We could exploit the difference between the CMB frame and the interstellar medium (say with a minimagnetosphere) or more immediately we could produce energy from a slight drag on the CMB frame, gradually bringing the speed of the planet (and through the slight force of gravity, our sun) to rest WRT to the CMB. The mass of the sun and 400km/s is a massive store of energy.

What are you talking about? Their concept is a magnetoplasmadynamic thruster that uses virtual particles as the plasma. Okay, that does sounds far fetched, but you can't get free energy from it. While at first glance it seems like a reactionless drive, it is not because the virtual particles are the reaction mass. KE would still increase at the rate of velocity squared.

http://en.wikipedia.org/wiki/Magnetoplasmadynamic_thruster (http://en.wikipedia.org/wiki/Magnetoplasmadynamic_thruster)

Title: Re: EM Drive Developments
Post by: Robotbeat on 08/02/2014 04:17 PM
It's not a scientific strawman. It's a valid criticism. Propellantless thrust already requires new physics. Also, all of the excitement over applications basically assume that what KelvinZero is saying is true.
Title: Re: EM Drive Developments
Post by: A_M_Swallow on 08/02/2014 04:26 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237812#msg1237812">Quote from: Robotbeat on 08/02/2014 05:23 AM</a>
You could use this device to harvest energy from the Universe one way or anoter. But anyway, in my opinion it's at least as bad to violate conservation of momentum.

To break conservation of momentum you have to show that the entire planet Earth was not moved in the opposite direction.  If something as simple as walking can move the Earth then very accurate strain gauges would need attaching to the vacuum chamber to check this.

Title: Re: EM Drive Developments
Post by: KelvinZero on 08/02/2014 04:32 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237936#msg1237936">Quote from: Robotbeat on 08/02/2014 04:17 PM</a>
It's not a scientific strawman. It's a valid criticism. Propellantless thrust already requires new physics. Also, all of the excitement over applications basically assume that what KelvinZero is saying is true.

Wouldn't it be cool though.. apart from the possible world ending, Fermi paradox solving bit ;)

Actually Im still trying to get my head around this thing that IslandPlaya brought up:
http://en.wikipedia.org/wiki/Cosmic_microwave_background#CMBR_dipole_anisotropy

That might knock a hole in my favorite FTL paradox also.

Title: Re: EM Drive Developments
Post by: cuddihy on 08/02/2014 04:47 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237936#msg1237936">Quote from: Robotbeat on 08/02/2014 04:17 PM</a>
It's not a scientific strawman. It's a valid criticism. Propellantless thrust already requires new physics. Also, all of the excitement over applications basically assume that what KelvinZero is saying is true.

Non sequitur. All physics not previously widely accepted is "new physics."

And it does not follow that because "anomalous thrust produced", or even "can change an object's momentum without expelling mass" that therefore "must require linear input of energy for linear increase in velocity".

Title: Re: EM Drive Developments
Post by: Prober on 08/02/2014 05:25 PM
Looks like the media has picked up on it.

NASA confirms ‘impossible’ thruster actually works, could revolutionize space travel

Read more: http://www.digitaltrends.com/cool-tech/nasa-confirms-impossible-space-drive-actually-works-revolutionize-space-travel/#ixzz39FyGJbBH
Follow us: @digitaltrends on Twitter | digitaltrendsftw on Facebook

Title: Re: EM Drive Developments
Post by: Robotbeat on 08/02/2014 05:53 PM
...powered by wishful thinking.
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/02/2014 06:04 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237652#msg1237652">Quote from: Star One on 08/01/2014 10:40 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237651#msg1237651">Quote from: Cherokee43v6 on 08/01/2014 10:38 PM</a>
em-drives, ion engines, VASIMIR, Alcubrier... seem's we have a bazillion ways to go fast on very little fuel once we are up there...  But we still have to deal with the rocket equation to get there in the first place.  I'm waiting to see a /real/ game-changer come along... a provable means of getting out of the gravity well that beats rockets.

Sadly, we are rather lacking in acceptable options there still.

I think even if the EM thruster actually worked as advertised that it's my understanding you would still need a jet engine for an aircraft or rocket for a spacecraft to get off the ground in the first place.

sure we are dealing with micro newtons now... but Dr White's 2013 symposium talk extrapolated to extraordinary levels thrust for trips to Jupiter and points beyond ...all the way to the tau point if i recall correctly. his device is a different make and model but the QVPT does the same sort of thing as this generally using the same mechanism of operation in broad terms.

talk is here. the first portion of the talk is on QVPT and he hits all around but not in his classified results too.

EDIT: looks like i have the wrong vid. this is mostly about his warp drive. i will make a separate post when i find the proper video. Sorry, guys.


Title: Re: EM Drive Developments
Post by: Danderman on 08/02/2014 06:41 PM
I would lay my money on instrument error. 

I would also lay money on nothing substantive coming out of this, much like cold fusion, where adherents claiming that progress is being made secretly, but no real world applications after 25 years.

Title: Re: EM Drive Developments
Post by: SteveKelsey on 08/02/2014 06:46 PM
I step into this debate with trepidation. My perspective is that neither proponent has developed a successful characterisation of any effect, hence the confusion over the test article modified to not perform, and the confusion over Shawyer's description leading to his theory gaining little traction. However- having exercised my doubts, and well aware of the problems inherent in using an analogy, one presents itself to me in this case. A rocket motor utilises the shape of the nozzle to convert chemical energy to a directed force, which we call thrust. Is it possible that all that happening here is microwave energy is converted to thrust by the shape of the chamber?
It's a horribly inefficient conversion that may be due to the net sum of all the forces applied of the chamber. It is most likely more complex and as I am not clear on Shawyer's use of relativity as part of his description of the system I am ignoring that, but from what I have read I am in good company. Just an idle thought on a rainy saturday evening in Cumbria so if you think it doesn't hold water let it pass         : )
Title: Re: EM Drive Developments
Post by: SteveKelsey on 08/02/2014 06:49 PM
Unfortunately there are no real world applications for any fusion system to date.
Title: Re: EM Drive Developments
Post by: CW on 08/02/2014 07:39 PM
Hello all,

I think there is one elephant in the room that nobody seems to notice. If the drive is supposed to gain impulse by interaction with virtual particles of the quantum vacuum, then these particles obviously have to be accelerated in the opposed direction in which the drive is accelerated.

Here comes now the elephant: When those accelerated virtual particles (which pop in an out of existence spontaneously) disappear again to who-knows-where, what happens to the impulse that these particles previously gained.. is it gone? I can hardly imagine that this should be the case. So.. where would the imparted impulse on the virtual particles go? Ideas? On the other hand.. please correct me if I'm wrong.. I seem to remember some knowledge that virtual particles were not subject to impulse conservation?

Regards
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 07:47 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237967#msg1237967">Quote from: SteveKelsey on 08/02/2014 06:46 PM</a>
I step into this debate with trepidation. My perspective is that neither proponent has developed a successful characterisation of any effect, hence the confusion over the test article modified to not perform, and the confusion over Shawyer's description leading to his theory gaining little traction. However- having exercised my doubts, and well aware of the problems inherent in using an analogy, one presents itself to me in this case. A rocket motor utilises the shape of the nozzle to convert chemical energy to a directed force, which we call thrust. Is it possible that all that happening here is microwave energy is converted to thrust by the shape of the chamber?
It's a horribly inefficient conversion that may be due to the net sum of all the forces applied of the chamber. It is most likely more complex and as I am not clear on Shawyer's use of relativity as part of his description of the system I am ignoring that, but from what I have read I am in good company. Just an idle thought on a rainy saturday evening in Cumbria so if you think it doesn't hold water let it pass         : )
We are a friendly bunch here SteveKelsey, never be afraid to put your oar in!  :)
IMHO a good post! I am unclear on almost all of the theory that predicts the way these things should work. Doesn't stop me spouting my speculations though!
It can't however work like you are suggesting. The microwave cavity is closed. Imagine a Merlin engine encased in a large metal sphere. Would it go anywhere when ignited? No.
It's a rainy and windy Saturday night up here in the Outer Hebs too! But what better way to pass some time than talking about possibly world changing tech.
 ;D

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 07:57 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237982#msg1237982">Quote from: CW on 08/02/2014 07:39 PM</a>
Hello all,

I think there is one elephant in the room that nobody seems to notice. If the drive is supposed to gain impulse by interaction with virtual particles of the quantum vacuum, then these particles obviously have to be accelerated in the opposed direction in which the drive is accelerated.

Here comes now the elephant: When those accelerated virtual particles (which pop in an out of existence spontaneously) disappear again to who-knows-where, what happens to the impulse that these particles previously gained.. is it gone? I can hardly imagine that this should be the case. So.. where would the imparted impulse on the virtual particles go? Ideas? On the other hand.. please correct me if I'm wrong.. I seem to remember some knowledge that virtual particles were not subject to impulse conservation?

Regards
Welcome to the forum!
Short answer. I don't know. I don't think anyone knows...
Interesting point of discussion though! Great first post mate!

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/02/2014 07:59 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237892#msg1237892">Quote from: Silversheep2011 on 08/02/2014 01:24 PM</a>
The Wright brothers,
Were two American brothers, inventors, and aviation pioneers who are credited with inventing and building the world's first successful airplane and making the first controlled, powered and sustained heavier-than-air human flight, on December 17, 1903

Prior to that, It could be said that, "Heaver than air was consider impossible".

That's completely wrong.  Since the start of modern physics in the era of Newton, no serious physicist thought heavier than air flight violated the laws of physics.  It was always considered an engineering challenge, not a violation of the laws of physics.

The scientific community is far smarter than your fantasies imagine it to be.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 08:12 PM
Consider a neutron in free space. It is surrounded by a malestrom of pair-production events all around it. It is perturbed on the Planck scale by all these events, but as in Brownian motion they average out to nearly zero.
Remember we are talking Planck scale perturbations here. I.e: un-observable.
What if you could bias the pair-production events somehow so that there was a preferred vector of momentum?
Would we see our neutron being accelerated in a particular direction?
 ;)
Title: Re: EM Drive Developments
Post by: CW on 08/02/2014 08:18 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237994#msg1237994">Quote from: IslandPlaya on 08/02/2014 08:12 PM</a>
Consider a neutron in free space. It is surrounded by a malestrom of pair-production events all around it. It is perturbed on the Planck scale by all these events, but as in Brownian motion they average out to nearly zero.
Remember we are talking Planck scale perturbations here. I.e: un-observable.
What if you could bias the pair-production events somehow so that there was a preferred vector of momentum?
Would we see our neutron being accelerated in a particular direction?
 ;)

Since neutrons can't be accelerated by electromagnetism AFAIK, this effect would sound similar to what gravity would be able to do. I mean, gravity is a gradient in space, right?

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 08:23 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237995#msg1237995">Quote from: CW on 08/02/2014 08:18 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237994#msg1237994">Quote from: IslandPlaya on 08/02/2014 08:12 PM</a>
Consider a neutron in free space. It is surrounded by a malestrom of pair-production events all around it. It is perturbed on the Planck scale by all these events, but as in Brownian motion they average out to nearly zero.
Remember we are talking Planck scale perturbations here. I.e: un-observable.
What if you could bias the pair-production events somehow so that there was a preferred vector of momentum?
Would we see our neutron being accelerated in a particular direction?
 ;)

Since neutrons can't be accelerated by electromagnetism AFAIK, this effect would sound similar to what gravity would be able to do. I mean, gravity is a gradient in space, right?
I'm not talking about EM acceleration, hence my choice of the neutron to make things clear.
I'm talking about pair-production in the false vacuum being able to transfer momentum along a particular vector, under conditions that are created by the device we are discussing.

Title: Re: EM Drive Developments
Post by: CW on 08/02/2014 08:29 PM
So you mean that by some mechanism, the maelstrom of vectors in quantum vacuum, which usually time average to zero, change locally in the drive to produce a non-zero vector in the preferred direction? Like some sort of mechanism to manipulate the "natural statistics" of space? :)
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 08:31 PM
Yes. I suppose that is exactly what I'm saying.
Sounds crazy when you put it like that! I'm just putting forward ways the anomalous thrust could be explained *if* it is real...
Title: Re: EM Drive Developments
Post by: Star One on 08/02/2014 08:33 PM
Slightly odd article from the Verge on this. What I mean is they seem to be sceptical about this because of Guido Fetta's qualifications, which is a bit harsh.

http://www.theverge.com/2014/8/1/5959637/nasa-cannae-drive-tests-have-promising-results
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 08:44 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238003#msg1238003">Quote from: Star One on 08/02/2014 08:33 PM</a>
Slightly odd article from the Verge on this. What I mean is they seem to be sceptical about this because of Guido Fetta's qualifications, which is a bit harsh.

http://www.theverge.com/2014/8/1/5959637/nasa-cannae-drive-tests-have-promising-results
We see this everyday.
People who criticize CAGW are hacked down because the are not in the 'Climate Science Club' and don't have qualifications in 'Climate Science' (sic)
In this case 'He can't possibly know what he is talking about, he only knows about chemistry!'
Sigh.
Maybe the tech doesn't work, but I would fight and fight for the ability of people to try and fail at this sort of stuff.
/rant over

Title: Re: EM Drive Developments
Post by: RonM on 08/02/2014 08:50 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238002#msg1238002">Quote from: IslandPlaya on 08/02/2014 08:31 PM</a>
Yes. I suppose that is exactly what I'm saying.
Sounds crazy when you put it like that! I'm just putting forward ways the anomalous thrust could be explained *if* it is real...

It does sound crazy, but it is worth a little testing. If we don't test theory to see if it works, then it becomes philosophy.

Odds are the anomalous thrust produced is just experimental error. They'll find out as they do more testing.

Title: Re: EM Drive Developments
Post by: CW on 08/02/2014 09:02 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238002#msg1238002">Quote from: IslandPlaya on 08/02/2014 08:31 PM</a>
Yes. I suppose that is exactly what I'm saying.
Sounds crazy when you put it like that! I'm just putting forward ways the anomalous thrust could be explained *if* it is real...

OK, here's an idea. The resonant cavity's purpose is to produce standing waves, right? So, basically it's a precise arrangement of conducting plates which reflect EM waves back and forth. For some reason, this reminds me of a "macro" Casimir cavity, just on a different scale and with "real" photons. So, what if.. this EM drive acted (by coincidence) as some weird form of "macro" Casimir cavity and its specific shape (accidentally) produced a preferred vector, working with real photons? I seem to remember that specific geometries of Casimir cavities were calculated to be able to produce a preferred vector of motion. I didn't find that piece of info yet again, or perhaps I remember wrongly. Maybe someone else knows better?

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/02/2014 09:15 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238005#msg1238005">Quote from: IslandPlaya on 08/02/2014 08:44 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238003#msg1238003">Quote from: Star One on 08/02/2014 08:33 PM</a>
Slightly odd article from the Verge on this. What I mean is they seem to be sceptical about this because of Guido Fetta's qualifications, which is a bit harsh.

http://www.theverge.com/2014/8/1/5959637/nasa-cannae-drive-tests-have-promising-results
We see this everyday.
People who criticize CAGW are hacked down because the are not in the 'Climate Science Club' and don't have qualifications in 'Climate Science' (sic)
In this case 'He can't possibly know what he is talking about, he only knows about chemistry!'
Sigh.
Maybe the tech doesn't work, but I would fight and fight for the ability of people to try and fail at this sort of stuff.
/rant over

Nobody I've ever heard of has argued that anybody shouldn't have the right to try whatever they want, with their own resources, and the resources of anyone wishing to spend them that way.

However, resources are limited, and it's perfectly legitimate to argue about whether a particular line of research is worth putting the resources into, and to try to convince others not to put their own resources into a particular line of research.

There are tens of thousands of grad students struggling to find research dollars to continue their research into all sorts of topics in physics and aerospace engineering.

I personally find it sad that a very small number of fringe people who make outlandish claims get so much attention -- attention that, to my mind, would be better focused on more mainstream science and engineering, which is, I believe, far more likely to get us eventually to the breakthroughs we all would like to see.

Real advances in science come from careful experimentation and analysis, the discovery of anomalous results, and the advancement of theories to explain those results, without any particular engineering goal in mind.  Deciding to try to design a device that violates limitations of known physics gets it backwards -- it's the approach of amateurs.

Title: Re: EM Drive Developments
Post by: Star One on 08/02/2014 09:21 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238013#msg1238013">Quote from: ChrisWilson68 on 08/02/2014 09:15 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238005#msg1238005">Quote from: IslandPlaya on 08/02/2014 08:44 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238003#msg1238003">Quote from: Star One on 08/02/2014 08:33 PM</a>
Slightly odd article from the Verge on this. What I mean is they seem to be sceptical about this because of Guido Fetta's qualifications, which is a bit harsh.

http://www.theverge.com/2014/8/1/5959637/nasa-cannae-drive-tests-have-promising-results
We see this everyday.
People who criticize CAGW are hacked down because the are not in the 'Climate Science Club' and don't have qualifications in 'Climate Science' (sic)
In this case 'He can't possibly know what he is talking about, he only knows about chemistry!'
Sigh.
Maybe the tech doesn't work, but I would fight and fight for the ability of people to try and fail at this sort of stuff.
/rant over

Nobody I've ever heard of has argued that anybody shouldn't have the right to try whatever they want, with their own resources, and the resources of anyone wishing to spend them that way.

However, resources are limited, and it's perfectly legitimate to argue about whether a particular line of research is worth putting the resources into, and to try to convince others not to put their own resources into a particular line of research.

There are tens of thousands of grad students struggling to find research dollars to continue their research into all sorts of topics in physics and aerospace engineering.

I personally find it sad that a very small number of fringe people who make outlandish claims get so much attention -- attention that, to my mind, would be better focused on more mainstream science and engineering, which is, I believe, far more likely to get us eventually to the breakthroughs we all would like to see.

Real advances in science come from careful experimentation and analysis, the discovery of anomalous results, and the advancement of theories to explain those results, without any particular engineering goal in mind.  Deciding to try to design a device that violates limitations of known physics gets it backwards -- it's the approach of amateurs.

You might want to be rather careful in what you say here otherwise it might look like you're casting aspersions on the NASA scientists and their decision to investigate this.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 09:57 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238011#msg1238011">Quote from: CW on 08/02/2014 09:02 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238002#msg1238002">Quote from: IslandPlaya on 08/02/2014 08:31 PM</a>
Yes. I suppose that is exactly what I'm saying.
Sounds crazy when you put it like that! I'm just putting forward ways the anomalous thrust could be explained *if* it is real...

OK, here's an idea. The resonant cavity's purpose is to produce standing waves, right? So, basically it's a precise arrangement of conducting plates which reflect EM waves back and forth. For some reason, this reminds me of a "macro" Casimir cavity, just on a different scale and with "real" photons. So, what if.. this EM drive acted (by coincidence) as some weird form of "macro" Casimir cavity and its specific shape (accidentally) produced a preferred vector, working with real photons? I seem to remember that specific geometries of Casimir cavities were calculated to be able to produce a preferred vector of motion. I didn't find that piece of info yet again, or perhaps I remember wrongly. Maybe someone else knows better?
I like this idea. What we are seeing is a macro-Casimir effect. Maybe like we see macro superconductivity from quantam Cooper-pairings?
Who knows?

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/02/2014 10:00 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238016#msg1238016">Quote from: Star One on 08/02/2014 09:21 PM</a>
You might want to be rather careful in what you say here otherwise it might look like you're casting aspersions on the NASA scientists and their decision to investigate this.

This is one little corner of NASA.  NASA is a huge organization with lots and lots of people working on lots of things.  Sonny White and friends are not equivalent to NASA as a whole.

And there's nothing wrong with complaining that this one small part of NASA is wasting precious resources that could be better spent, and misleading the public by letting the NASA name get attached to wishful thinking in the guise of science.

Title: Re: EM Drive Developments
Post by: Star One on 08/02/2014 10:12 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238021#msg1238021">Quote from: ChrisWilson68 on 08/02/2014 10:00 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238016#msg1238016">Quote from: Star One on 08/02/2014 09:21 PM</a>
You might want to be rather careful in what you say here otherwise it might look like you're casting aspersions on the NASA scientists and their decision to investigate this.

This is one little corner of NASA.  NASA is a huge organization with lots and lots of people working on lots of things.  Sonny White and friends are not equivalent to NASA as a whole.

And there's nothing wrong with complaining that this one small part of NASA is wasting precious resources that could be better spent, and misleading the public by letting the NASA name get attached to wishful thinking in the guise of science.

I like the way you're pre-judging the outcome of this, now that's not very scientific. Such attitudes are almost as bad in my book as the pseudo-science that often attaches itself online too such pronouncements.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 10:13 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238013#msg1238013">Quote from: ChrisWilson68 on 08/02/2014 09:15 PM</a>
Real advances in science come from careful experimentation and analysis, the discovery of anomalous results, and the advancement of theories to explain those results, without any particular engineering goal in mind.
Which is exactly what the authors are trying to do.

Title: Re: EM Drive Developments
Post by: Star One on 08/02/2014 10:15 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238027#msg1238027">Quote from: IslandPlaya on 08/02/2014 10:13 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238013#msg1238013">Quote from: ChrisWilson68 on 08/02/2014 09:15 PM</a>
Real advances in science come from careful experimentation and analysis, the discovery of anomalous results, and the advancement of theories to explain those results, without any particular engineering goal in mind.
Which is exactly what the authors are trying to do.

That point seems to have escaped the OP.

Title: Re: EM Drive Developments
Post by: CW on 08/02/2014 10:43 PM
Coming back to the issue of the virtual particle pairs of quantum space possibly being used for propulsion and seemingly vanishing impulse in this setup, when the pairs disappear again into "nothingness".. something interesting might happen, if this is not all a systematic measuring error.

So here comes another idea. If we were to consider quantum space itself to be made up of virtual particle pairs et cetera and made an analogy of quantum space being some sort of weird virtual liquid or gas with the particle pairs as 'liquid' or 'gas' molecules/atoms (or maybe even being a perfect virtual plasma e.g. of electrons and positrons etc), a space drive using a technologically enabled, controlled particle pair interaction to 'push' against this 'substance' should logically result in creating a sort of particle pair 'stream' exiting the space drive in the opposed direction to the drive's acceleration, to keep impulse conservation intact. That would be analogous to a submarine using propellers to push water backwards, while itself is propelled forward.

Now, if we considered quantum space as a medium to be 'expelled' behind the drive, wouldn't that imply quantum space itself were being moved? And what would happen, if that moving 'medium' hits on some other object. Would there be some 'virtual particle wind or stream' behind the drive's vector of acceleration, as can be observed in water for submarines?

Questions over questions :) .
Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/02/2014 11:01 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238027#msg1238027">Quote from: IslandPlaya on 08/02/2014 10:13 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238013#msg1238013">Quote from: ChrisWilson68 on 08/02/2014 09:15 PM</a>
Real advances in science come from careful experimentation and analysis, the discovery of anomalous results, and the advancement of theories to explain those results, without any particular engineering goal in mind.
Which is exactly what the authors are trying to do.

You're missing my point.  Looking around randomly for anomalies isn't a very good strategy.  Neither is designing a device based on a misunderstanding of known physics to see if it happens to work.  There are better places to choose to look for anomalies.

You also missed the "careful" point.  Sonny White and friends have a long history of claims based on experimental setups that have been criticized as poorly controlled.

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/02/2014 11:05 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238028#msg1238028">Quote from: Star One on 08/02/2014 10:15 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238027#msg1238027">Quote from: IslandPlaya on 08/02/2014 10:13 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238013#msg1238013">Quote from: ChrisWilson68 on 08/02/2014 09:15 PM</a>
Real advances in science come from careful experimentation and analysis, the discovery of anomalous results, and the advancement of theories to explain those results, without any particular engineering goal in mind.
Which is exactly what the authors are trying to do.

That point seems to have escaped the OP.

The point that escaped you is the part where I said "without any particular engineering goal in mind".

Having a goal of making a reactionless drive and then looking for physics to make it work is backwards.  That's not how discoveries in physics are made.  They are made by not having any preconceived ideas about applications.

Title: Re: EM Drive Developments
Post by: frobnicat on 08/02/2014 11:14 PM
Is there theoretical limits to how high the Q factor of a resonant cavity can go ? If constant thrust necessitates constant power above some threshold, then "propellentless propulsion" doesn't really escape the rocket equation because of mass energy equivalence : all the energy put into the engine must come at the price of "burned" mass. A photon engine is a well understood example of changing "object's momentum without expelling mass" as photons have no rest mass, but they require energy (burning fuel mass) to be created... How the proposal would be better than a photon rocket ?
If the hypothetical thrust effect is limited to be small enough compared to the required power, then even a constant thrust (not depending on speed) at constant power doesn't imply "free energy" as the ship would bleed enough mass flow in the conversion to the required power to maybe equal but not beat a perfect physically respectable photon rocket. Granted, at slower speeds the ability to efficiently "push" on space or whatever without expelling reaction mass would be convenient as a few percent of mass of energy fuel only is lost in the process and the (non relativistic part of) rocket equation kind of vanishes...
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 11:25 PM
As far as I know there are no theoretical limits on the Q factor in a superconducting cavity.
Practical limits is another thing entirely of course...
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 11:33 PM
I have not seen 'free energy' mentioned for quite a few posts now.
Thank you all for your reasoned ideas. Much to sleep on...
Another thought, although it may seem to make me more of kook than some people already think...
If this effect was real, do you think we would hear anything true about it? The military would be all over it like a rash...
Just a thought.
Title: Re: EM Drive Developments
Post by: Silversheep2011 on 08/02/2014 11:35 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238039#msg1238039">Quote from: ChrisWilson68 on 08/02/2014 11:05 PM</a>
They are made by not having any preconceived ideas about applications.

How do you look for a new law in physics?

A friend shared this with me. It makes the point well.
and Visa versa

https://www.youtube.com/watch?v=b240PGCMwV0&feature=player_embedded

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/02/2014 11:43 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238039#msg1238039">Quote from: ChrisWilson68 on 08/02/2014 11:05 PM</a>
Having a goal of making a reactionless rocket drive and then looking for physics to make it work is backwards.  That's not how discoveries in physics are made.  They are made by not having any preconceived ideas about applications.
Strikethru mine.
Do you see how silly this sounds?

Title: Re: EM Drive Developments
Post by: CW on 08/02/2014 11:44 PM
If I'm not mistaken, the magnetic field strength that a superconductor is subjected to externally, has a well-defined upper limit, before superconductivity breaks down. So I'm a bit worried that there's only a certain amount of photons that can be within such a cavity at any given instant in time, due to the magnetic field component of the photons possibly impinging on the surface of the superconductor at the same time. Or perhaps that is no problem at all, maybe someone can elaborate on behavior of superconductor and photon interaction.

IMHO the charm of a working EM drive would be that, in the best case, it would become possible to create ultra-high Q cavities (minimal losses), pump them full of photons and let the device counteract 1:1 Earth's gravity for all kinds of transportation purposes with small energy requirements. I'm not so sure if space travel were the most prominent application of such a device. But who knows.
Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/03/2014 12:44 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238047#msg1238047">Quote from: IslandPlaya on 08/02/2014 11:43 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238039#msg1238039">Quote from: ChrisWilson68 on 08/02/2014 11:05 PM</a>
Having a goal of making a reactionless rocket drive and then looking for physics to make it work is backwards.  That's not how discoveries in physics are made.  They are made by not having any preconceived ideas about applications.
Strikethru mine.
Do you see how silly this sounds?

No, it's not silly when you replace the word "reactionless" with "rocket".

You are still missing my point.  My point is that physics and engineering are two different things.  When you go to do engineering, you come up with a device you would like to create, and you use known physics to create it.  You you do physics, you don't start with an engineering problem you'd like to solve, you start by looking for what part of the experimental envelope of the behavior of the world hasn't been adequately explored, and you start exploring it.  Trying to find new physics by doing engineering is foolish.

Physics is about discovering what the truth of the universe as it already exists is.  Engineering is about using the knowledge from physics to make changes in the universe.  The approaches to the two subjects that yield best results are very different.

Title: Re: EM Drive Developments
Post by: mlindner on 08/03/2014 01:54 AM
The fact that this article is even being considered by NSF members has me seriously worried about the future of American technological might.

Have we really gotten to the point that something akin to free energy generation that quackpots trot around on youtube with has gotten smart people this confused?

This technology has fraud written all over it. The creator will profit monetarily if it succeeds. He only agrees to let you test it if you agree that his theories are correct. The test device itself was built by the creator. The NEGATIVE test device showed positive results, thus completely invalidating the test. The effects of atmosphere were not removed from the testing chamber. The effects of outgassing and mass loss were not accounted for. The AIAA paper in question only has two references, one to the creator's website and one to the other faulty Chinese test.

This is terrible all over. The world is being given the runaround by this guy.

http://arstechnica.com/science/2014/08/dont-buy-stock-in-impossible-space-drives-just-yet/

Direct link to the pdf (this won't work unless your univeristy/company has a subscription). http://arc.aiaa.org/doi/pdf/10.2514/6.2014-4029
Title: Re: EM Drive Developments
Post by: mlindner on 08/03/2014 02:09 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237829#msg1237829">Quote from: KelvinZero on 08/02/2014 07:49 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237816#msg1237816">Quote from: Optimistic Brian on 08/02/2014 05:53 AM</a>
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

Wow that's a perfect way to debunk this. I was looking for something short and sweet like this.

Title: Re: EM Drive Developments
Post by: cuddihy on 08/03/2014 02:55 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238073#msg1238073">Quote from: mlindner on 08/03/2014 02:09 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237829#msg1237829">Quote from: KelvinZero on 08/02/2014 07:49 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237816#msg1237816">Quote from: Optimistic Brian on 08/02/2014 05:53 AM</a>
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

Wow that's a perfect way to debunk this. I was looking for something short and sweet like this.

[facepalm]
Brevity is the soul of wit...and a close companion of confirmation bias, apparently.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/03/2014 03:22 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238073#msg1238073">Quote from: mlindner on 08/03/2014 02:09 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237829#msg1237829">Quote from: KelvinZero on 08/02/2014 07:49 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237816#msg1237816">Quote from: Optimistic Brian on 08/02/2014 05:53 AM</a>
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

Wow that's a perfect way to debunk this. I was looking for something short and sweet like this.

yesh. you wouldn't want to try to find out where the unexpected energy comes from or something all scientific like. here is the issue with that. random debunking is bunkum. whatever the root cause of a phenomenon whether valid or not you just say it's swamp gas. it does not really explain what happened. it's every bit as much bunk as claiming it's Klaatu.

Title: Re: EM Drive Developments
Post by: mlindner on 08/03/2014 03:31 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238084#msg1238084">Quote from: Stormbringer on 08/03/2014 03:22 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238073#msg1238073">Quote from: mlindner on 08/03/2014 02:09 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237829#msg1237829">Quote from: KelvinZero on 08/02/2014 07:49 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237816#msg1237816">Quote from: Optimistic Brian on 08/02/2014 05:53 AM</a>
This is even more exciting than the warp drive research, since if it pans out we could have practical applications almost immediately (i.e., within a couple of years).  No more gravity assists would ever be necessary again.
And free energy.

(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.
(*) Classical physics lets you extract energy proportional to the velocity squared.

Wow that's a perfect way to debunk this. I was looking for something short and sweet like this.

yesh. you wouldn't want to try to find out where the unexpected energy comes from or something all scientific like. here is the issue with that. random debunking is bunkum. whatever the root cause of a phenomenon whether valid or not you just say it's swamp gas. it does not really explain what happened. it's every bit as much bunk as claiming it's Klaatu.

I'm all for using science to attempt to validate the claims. See my previous post. I want to see a proper experiment done with a proper negative test that demonstrates non-action and a proper test that accounts for variables of mass loss from evaporation/outgassing and proper testing in a vacuum to cancel out effects of movements of the atmosphere. I'll not believe an ounce of this until we get those minimum of tests done. After that some peer verification and tests by non-interested parties (namely parties that won't make money from the success) would be good as well.

I was mainly looking for a short description of a major issue with the experiment that I can feed to people to prompt them to engage their brains for a minute rather than shoveling the bull**** down their throats without thinking. After that some discussion can be sparked to realize the issues at hand.

Title: Re: EM Drive Developments
Post by: KelvinZero on 08/03/2014 04:10 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238045#msg1238045">Quote from: IslandPlaya on 08/02/2014 11:33 PM</a>
I have not seen 'free energy' mentioned for quite a few posts now.
Yeah.. I was thinking it isn't really appropriate to keep explaining this repeatedly in specific versions propellantless thrust threads. It does sort of derail the thread, which should only concern it self with explaining how it works around this particular well known issue. But everyone should understand what the issue is.

I liked your CMB suggestion, because then we can at least discuss how it behaves in particular circumstances. This is hugely powerful. The moment you start looking at a useful description of how it behaves whole new unexpected behavior can be discovered, such as extracting energy from the difference in velocity of the solar system and the CMB frame.. the existence of which still boggles my mind a bit.

If the theory is correct yet is not obvious to the thousands of physicists out there who are brighter than I, then obviously it will be beyond my understanding. I would just like to understand the claim to the level of a science fiction writer, so I could describe what it actually means to my fledgling galactic citizen.

I think rather than repeating these over and over, we should have a general thread and just refer to it. Im hoping other people will add their favorite paradox examples also.
<a href="http://forum.nasaspaceflight.com/index.php?topic=35332.msg1238102#msg1238102">Quote from: KelvinZero on 08/03/2014 05:06 AM</a>
..General explanation here...
Everyone should understand the issue, and then threads like this can just focus on how this version claims to get around it.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/03/2014 04:38 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238086#msg1238086">Quote from: mlindner on 08/03/2014 03:31 AM</a>


I was mainly looking for a short description of a major issue with the experiment that I can feed to people to prompt them to engage their brains for a minute rather than shoveling the bull**** down their throats without thinking. After that some discussion can be sparked to realize the issues at hand.

i think there are two major issues.

1. the signal is very small. this makes it easy for uncontrolled for unanticipated spurious signals to get in there. critic can claim this is what caused it all day long. it's hard to disprove.

2. in this experiment it appears the control test article got the same signal. I do not think this is as damning as it could be because of the signals found by other researchers with (similar devices of differing design details.)  E.G. Dr Woodward's design is a solid state peizoelectric stack. he gets a thrust signal. Dr White has a capacitor and coil ring and gets thrust signals. the Egyptian girl uses a moving casimir mirror and gets a thrust signal. The Chinese use Shayer's design as a starting point and get a much stronger thrust signal than he did or NASA testing got.

Title: Re: EM Drive Developments
Post by: FlyingMoose on 08/03/2014 04:43 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237376#msg1237376">Quote from: ChrisWilson68 on 08/01/2014 09:57 AM</a>
The EmDrive and White's theories are the opposite -- they put the theory first and then go looking for evidence afterwards.  In both cases, the theories claim to be consequences of existing theories in physics, but reputable physicists say that in fact they come from misunderstandings of current theories.

That is incorrect.  This discovery came about because Shawyer was trying to explain the thrust generated by the microwave transmitters on satellites which exceeded what was expected and required additional fuel to correct.

Title: Re: EM Drive Developments
Post by: FlyingMoose on 08/03/2014 05:46 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237829#msg1237829">Quote from: KelvinZero on 08/02/2014 07:49 AM</a>
(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.

How is this any different from an ion thruster?

If you do one burn to bring a satellite up to 10 m/s, and then another with the same energy that brings it to 20 m/s, you have the same phenomenon.  In the second burn, you get more kinetic energy than in the first burn, even though your thruster expended the same amount of energy.

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/03/2014 05:52 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238111#msg1238111">Quote from: FlyingMoose on 08/03/2014 05:46 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237829#msg1237829">Quote from: KelvinZero on 08/02/2014 07:49 AM</a>
(*) Propellantless propulsion lets you increase velocity proportional to the energy you put in.

How is this any different from an ion thruster?

If you do one burn to bring a satellite up to 10 m/s, and then another with the same energy that brings it to 20 m/s, you have the same phenomenon.  In the second burn, you get more kinetic energy than in the first burn, even though your thruster expended the same amount of energy.

The difference is that with the ion thruster you had to put in more energy for the first 10 m/s because you had to accelerate both the satellite and the propellant you're going to use for the second burn.  You can think of it as the propellant for the second burn already having a bunch of kinetic energy from the first burn and you're using both that kinetic energy already in the prop plus the electric energy of the thruster to get the second 10 m/s of delta-v.

Title: Re: EM Drive Developments
Post by: MP99 on 08/03/2014 06:34 AM



<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237927#msg1237927">Quote from: cuddihy on 08/02/2014 03:56 PM</a>
What this thesis ignores is that none of these theories extend how their devices would function as velocity increases.

[quote name="RonM" post=1237898 timestamp=1406988473]propulsive momentum transfer via the quantum vacuum virtual plasma." [/quote]

Surely, interactions with the quantum vacuum should be unaffected by your velocity - you can always see a "version" of the vacuum as if you are currently at rest?

Cheers, Martin

Title: Re: EM Drive Developments
Post by: pagheca on 08/03/2014 07:01 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237271#msg1237271">Quote from: IslandPlaya on 08/01/2014 01:23 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237256#msg1237256">Quote from: JohnFornaro on 08/01/2014 12:37 AM</a>
I wouldn't dream of posting here....
I can understand the skepticism...
However the experimenters are all NASA scientists.
What is the problem? are you a better scientist John F? Or do you think the authors should be stripped of their NASA posts?
Maybe we should calm down and investigate further?
Heavens!

The problem is that the article linked is not a scientific paper (http://www.compoundchem.com/2014/04/02/a-rough-guide-to-spotting-bad-science), but a clearly preliminary technical report, the typical "hat on the seat" (copyrighted by me :) ) paper required to ensure to be the first IF a sensational result is confirmed in order to get an high citation index in the future.

(1) There has been no submission to refereed journals as for the standard scientific procedure.

(2) No details about the experimental setup have been given. So, it is impossible to submit the paper to a check, or to repeat the experiment to check for eventual involuntary errors by the scientists.

(3) there is the detail of thrust measured also in the "null" test article, that was unexpected and suggest there is a bias somewhere in the measuring system.

I would suspend any judgement till a proper paper is submitted to a proper journal. However, let me remind that extraordinary claims require extraordinary evidences, that is not the case here.

p.s. I had no time to read all the thread. So, apologies if there are other papers confirming the results. I refer just to one linked at the beginning of the thread, that is also the one linked to the digitaltrend article.

Title: Re: EM Drive Developments
Post by: Silversheep2011 on 08/03/2014 07:22 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238098#msg1238098">Quote from: FlyingMoose on 08/03/2014 04:43 AM</a>

This discovery came about because Shawyer was trying to explain the thrust generated by the microwave transmitters on satellites which exceeded what was expected and required additional fuel to correct.

This would really make an interesting subject to read or a comparison point to read up on.
who you be able to supply a link or a paper?

Title: Re: EM Drive Developments
Post by: john smith 19 on 08/03/2014 07:41 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238011#msg1238011">Quote from: CW on 08/02/2014 09:02 PM</a>
OK, here's an idea. The resonant cavity's purpose is to produce standing waves, right? So, basically it's a precise arrangement of conducting plates which reflect EM waves back and forth. For some reason, this reminds me of a "macro" Casimir cavity, just on a different scale and with "real" photons. So, what if.. this EM drive acted (by coincidence) as some weird form of "macro" Casimir cavity and its specific shape (accidentally) produced a preferred vector, working with real photons? I seem to remember that specific geometries of Casimir cavities were calculated to be able to produce a preferred vector of motion. I didn't find that piece of info yet again, or perhaps I remember wrongly. Maybe someone else knows better?
I'd say it's doubtful. It's about the lifetime of the  virtual particle before it cease to exist. AFAIK it's short, so they don't go very far before they disappear.

That said there is an interesting analogy. "Temperature" is a measure of a particles velocity, but if the particles are a gas they move in random directions stopped only by their collisions with the container walls or other particles. If you could filter the particles by velocity you would have a way to separate a gas at say room temperature into 2 streams, one quite a bit hotter, one quite a bit colder than room temperature.

Which sounds crazy.

Except the device is called a Ranque-Hilsch or vortex tube and has existed for about 70 years.

http://en.wikipedia.org/wiki/Vortex_tube

[WARNING Rampant speculation ]
If some sort of separation effect is happening with virtual particles (or could be made to) that might explain some thrust measurements.

Title: Re: EM Drive Developments
Post by: CW on 08/03/2014 08:03 AM
Considering that both test articles (null and 'real') seemed to produce some measurable thrust (systematic errors excluded), I have the impression that the scientists involved might be victims of the principle of logical implication, which states that from a wrong premise anything can follow, even the correct solution or answer. It would be interesting and very lucky, if they had stumbled upon some new principle by accident, starting from a physically incorrect premise or train of thought. In no case do I think that conservation of momentum can be broken. If real, there must be some form of opposite momentum occurring - in whatever unusual way yet to be observed.
Title: Re: EM Drive Developments
Post by: QuantumG on 08/03/2014 08:29 AM
Why are there now two threads for this nonsense?
Title: Re: EM Drive Developments
Post by: francesco nicoli on 08/03/2014 08:38 AM
I have no idea whether such a device could work. I see the consensus among physicists is that there should be some unobserved thing which simulates the effect. I believe that is mostly likely.
However, these guys are still nasa scientists, not exactly any Rossi whatsoever. Many of them have doctoral degrees and they are preparing a peer-review publication. So let's wait and see where and whether they made a mistake. As a scientist (albeit in a different discipline) I recognize here the holy fire of curiosity....
Title: Re: EM Drive Developments
Post by: CW on 08/03/2014 09:20 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238095#msg1238095">Quote from: Stormbringer on 08/03/2014 04:38 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238086#msg1238086">Quote from: mlindner on 08/03/2014 03:31 AM</a>


I was mainly looking for a short description of a major issue with the experiment that I can feed to people to prompt them to engage their brains for a minute rather than shoveling the bull**** down their throats without thinking. After that some discussion can be sparked to realize the issues at hand.

i think there are two major issues.

1. the signal is very small. this makes it easy for uncontrolled for unanticipated spurious signals to get in there. critic can claim this is what caused it all day long. it's hard to disprove.

2. in this experiment it appears the control test article got the same signal. I do not think this is as damning as it could be because of the signals found by other researchers with (similar devices of differing design details.)  E.G. Dr Woodward's design is a solid state peizoelectric stack. he gets a thrust signal. Dr White has a capacitor and coil ring and gets thrust signals. the Egyptian girl uses a moving casimir mirror and gets a thrust signal. The Chinese use Shayer's design as a starting point and get a much stronger thrust signal than he did or NASA testing got.

I think that what could bring this whole thing forward is to ask, what do all these experimental devices have in common that leads to a measured thrust - as different as they may seem. It could be a systematic error, but it would in turn also be an interesting insight if each and every one group doing these experiments made the same systematic errors. It seems possible, but the less likely, the more groups are independently letting the results get peer-reviewed. I'm looking forward to any kind of result.

Title: Re: EM Drive Developments
Post by: CharlieWildman on 08/03/2014 03:17 PM
Looking at the very small amount of thrust generated I suspect measurement error or a problem with how the testing was set up.

Correct me if I have this wrong but 30 to 50 micro Newtons of thrust (.000030 to .000050 Newton)  equates to about . .003 to .005 grams of thrust.

This tiny amount of force could easily be generated by air currents around what must be a warm to hot test article and could explain why the 'null' test article also produced thrust.

According to the NASA document http://ntrs.nasa.gov/search.jsp?R=20140006052 all testing was done in a vacuum chamber  'at ambient atmospheric pressure'.

I sure hope I'm wrong!!!   


Charlie


Title: Re: EM Drive Developments
Post by: mlindner on 08/03/2014 05:29 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238046#msg1238046">Quote from: Silversheep2011 on 08/02/2014 11:35 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238039#msg1238039">Quote from: ChrisWilson68 on 08/02/2014 11:05 PM</a>
They are made by not having any preconceived ideas about applications.

How do you look for a new law in physics?

A friend shared this with me. It makes the point well.
and Visa versa

https://www.youtube.com/watch?v=b240PGCMwV0&feature=player_embedded

It disagrees with experiment. So its wrong.

Title: Re: EM Drive Developments
Post by: hop on 08/03/2014 07:42 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238120#msg1238120">Quote from: pagheca on 08/03/2014 07:01 AM</a>
The problem is that the article linked is not a scientific paper (http://www.compoundchem.com/2014/04/02/a-rough-guide-to-spotting-bad-science), but a clearly preliminary technical report, the typical "hat on the seat" (copyrighted by me :) ) paper required to ensure to be the first IF a sensational result is confirmed in order to get an high citation index in the future.
A link to the actual paper may be found at
https://plus.google.com/117663015413546257905/posts/C7vx2G85kr4

However this is a conference paper, which in many cases aren't peer reviewed in the same way a journal paper would be. I'm not sure about this particular case.

In any case, if Baez summery is correct, there is really nothing worth talking about here... (which should be no surprise to anyone who read the original abstract)

Title: Re: EM Drive Developments
Post by: Star One on 08/03/2014 07:47 PM

It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract by NASA. Please see the quote below for more detail. Secondly, Eagle Works are currently building a suitable test article that will be shipped around to any lab that cares to test it according to further posts on there. They are also building a higher power device again according to posts on there.

Quote
No, the NASA folks shot themselves in the foot with this unclear NTRS abstract, which is very misleading once you have read the complete paper, as birchoff and I did. Birchoff is right, the paper is only $25, and now it's very clear that even ArsTechnica only read the NTRS abstract and didn't download the complete paper before writing and publishing their biased article. Very poor journalism.

The fact is (and the NTRS abstract does not explain this): Eagleworks tested one tapered (frustum) cavity, aka Shawyer's EmDrive; and two Cannae drives which are also asymmetric but different resonant cavities. The Cannae drive is said to work on a purported different principle than the EmDrive, according to its inventor Guido Fetta (a net Lorentz force imbalance of electrons upon top vs bottom wall of the cavity). According to this purported working principle, one Cannae drive had radial slots on its rim as required by Fetta in order to produce net thrust, and the second Cannae drive didn't have those slits and was intended to be a "null test device". But the Cannae null test article… also produced net thrust (20 to 40 µN of net thrust depending of the forward or backward direction).

We're talking of net thrust because of course the setup was also tested with a null 50 ohm load connected, in order to cancel the effect from the drives and detect any detect any spurious force due to EM coupling with the whole apparatus (which exists, at 9.6 µN) and this "null" spurious force was evidently subtracted from any thrust signal due to the drives then tested on the pendulum.

So the fact that the Cannae null test article produced a net thrust doesn't imply the experiment was screwed up. It rather showed that the radial slits required by Guido Fetta for propulsion are not the reason for the thrust, and another theoretical explanation is needed. Absolutely no news on the websites, including wikipedia, actually reports correctly this information.

We can go further by pointing another underestimated yet important fact of those NASA experiments: all tests articles (the EmDrive version, the Cannae drive version, and even the Cannae "null test" version) had a dielectric embedded within. This is a hint for a different theoretical explanation involving EM fields, proper acceleration, mass fluctuation and dielectrics. Maybe Mach effects (due to Mach's principle), as supposed by Woodward and Fearn within the GR theory, or within a scalar-tensor theory of gravity according to Minotti. As for Sonny White, he talks about compressible quantum vacuum fluctuations, but there are flaws about this conjecture regarding the thrust magnitude observed.

http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=2949&start=135#p114590

Title: Re: EM Drive Developments
Post by: Star One on 08/03/2014 08:04 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238122#msg1238122">Quote from: Silversheep2011 on 08/03/2014 07:22 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238098#msg1238098">Quote from: FlyingMoose on 08/03/2014 04:43 AM</a>

This discovery came about because Shawyer was trying to explain the thrust generated by the microwave transmitters on satellites which exceeded what was expected and required additional fuel to correct.

This would really make an interesting subject to read or a comparison point to read up on.
who you be able to supply a link or a paper?

I second that as I had wondered precisely how anyone even thought to look into this.

Title: Re: EM Drive Developments
Post by: hop on 08/03/2014 08:19 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238285#msg1238285">Quote from: Star One on 08/03/2014 07:47 PM</a>
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.

I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/03/2014 08:24 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238222#msg1238222">Quote from: CharlieWildman on 08/03/2014 03:17 PM</a>
Looking at the very small amount of thrust generated I suspect measurement error or a problem with how the testing was set up.

Correct me if I have this wrong but 30 to 50 micro Newtons of thrust (.000030 to .000050 Newton)  equates to about . .003 to .005 grams of thrust.

This tiny amount of force could easily be generated by air currents around what must be a warm to hot test article and could explain why the 'null' test article also produced thrust.

According to the NASA document http://ntrs.nasa.gov/search.jsp?R=20140006052 all testing was done in a vacuum chamber  'at ambient atmospheric pressure'.

I sure hope I'm wrong!!!   


Charlie

the chinese claim a much bigger thrust signal using a device evolved from Shayer's original design.

http://nextbigfuture.com/2014/07/renewed-hope-for-emdrive-with-nasa.html

Quote
Last year a Chinese team built its own EmDrive and confirmed that it produced 720 mN (about 72 grams) of thrust, enough for a practical satellite thruster. Such a thruster could be powered by solar electricity, eliminating the need for the supply of propellant that occupies up to half the launch mass of many satellites. The Chinese work attracted little attention; it seems that nobody in the West believed in it.

Title: Re: EM Drive Developments
Post by: Star One on 08/03/2014 08:41 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238297#msg1238297">Quote from: hop on 08/03/2014 08:19 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238285#msg1238285">Quote from: Star One on 08/03/2014 07:47 PM</a>
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.

I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.

My overall view is this is going to have wait for the further round of tests in the fall of this year, it looks like at this time there are just too many possible issues with this as it stands. It sounds like what they are planning next is either going to make or break this whole thing, at least that way it will not drag for twenty-five years as cold fusion has done.

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/03/2014 08:48 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238304#msg1238304">Quote from: Star One on 08/03/2014 08:41 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238297#msg1238297">Quote from: hop on 08/03/2014 08:19 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238285#msg1238285">Quote from: Star One on 08/03/2014 07:47 PM</a>
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.

I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.

My overall view is this is going to have wait for the further round of tests in the fall of this year, it looks like at this time there are just too many possible issues with this as it stands. It sounds like what they are planning next is either going to make or break this whole thing.

Nothing will ever break it.  The tests will fail to show convincing evidence of anomalous thrust, and the proponents of the various reactionless drives will come up with rationalizations for it and explain how they're working on new versions that will fix the problems.  It will continue without end.

Title: Re: EM Drive Developments
Post by: Star One on 08/03/2014 08:55 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238307#msg1238307">Quote from: ChrisWilson68 on 08/03/2014 08:48 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238304#msg1238304">Quote from: Star One on 08/03/2014 08:41 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238297#msg1238297">Quote from: hop on 08/03/2014 08:19 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238285#msg1238285">Quote from: Star One on 08/03/2014 07:47 PM</a>
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.

I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.

My overall view is this is going to have wait for the further round of tests in the fall of this year, it looks like at this time there are just too many possible issues with this as it stands. It sounds like what they are planning next is either going to make or break this whole thing.

Nothing will ever break it.  The tests will fail to show convincing evidence of anomalous thrust, and the proponents of the various reactionless drives will come up with rationalizations for it and explain how they're working on new versions that will fix the problems.  It will continue without end.

No it won't if it doesn't work EagleWorks will lose interest, the only reason it's getting attention is because of their interest.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/03/2014 09:09 PM
WRT the chinese thrust claim isn't that just 1280 grams away from 1 newton of Thrust?
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/03/2014 09:28 PM
Too important to be public. Military knows to release crappy results.
What do you think X34 is for?
Title: Re: EM Drive Developments
Post by: CW on 08/03/2014 09:39 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238307#msg1238307">Quote from: ChrisWilson68 on 08/03/2014 08:48 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238304#msg1238304">Quote from: Star One on 08/03/2014 08:41 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238297#msg1238297">Quote from: hop on 08/03/2014 08:19 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238285#msg1238285">Quote from: Star One on 08/03/2014 07:47 PM</a>
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.

I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.

My overall view is this is going to have wait for the further round of tests in the fall of this year, it looks like at this time there are just too many possible issues with this as it stands. It sounds like what they are planning next is either going to make or break this whole thing.

Nothing will ever break it.  The tests will fail to show convincing evidence of anomalous thrust, and the proponents of the various reactionless drives will come up with rationalizations for it and explain how they're working on new versions that will fix the problems.  It will continue without end.

In case it were all the same systematic blunder made by all groups involved with similar constructs, as likely or unlikely that may seem, a null-thrust demonstration under vacuum and subsequent working out of the details of such possible blunder, would at least add to the knowledge base as to what kind of measurement setup mistake was made. But in the end, we will see the actual results later this year - they will speak for themselves. Personally, I'd prefer an interesting result showing similar thrust under vacuum of course. But it's also great, if nothing of interest is observed. I'm just a bit worried about NASA's scientific reputation here, considering that a positive result was announced already..

Title: Re: EM Drive Developments
Post by: Raj2014 on 08/03/2014 11:07 PM
Has there been any new news on what NASA will do now?
Title: Re: EM Drive Developments
Post by: Elmar Moelzer on 08/04/2014 02:31 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238132#msg1238132">Quote from: QuantumG on 08/03/2014 08:29 AM</a>
Why are there now two threads for this nonsense?
I reported it to mods earlier, when it was only 5 posts long...
Posted another point over the in the other thread (well one of many on the subject): Where is the electricity coming from? Is it from a battery or capacitor on the thruster or a wall outlet. If it is the latter, then this could be an explanation for the thrust and it would also make the device irrelevant as a thruster.
I think that this mistake was made at least with the Cannae thruster experiment. I am not sure about Shawyers later experiments, though (his setups are pretty big and the power source might be on it).
Another problem is that the Cannae experiments were not done in a vacuum. We might just see ionized air flowing over the device, creating thrust.
Finally, we have the previously mentioned problem that the Null device also created thrust.
All this makes me highly skeptical, though I am more than willing to be positive surprised (would be cool if it worked).

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/04/2014 02:52 PM
Am not sure I understand the objection to power being provided from a source not physically connected to the device.

I understand that it would no longer be a closed system, but considering the scope of the mechanism of which these things are supposed to work then it is a moot point.
Why would it matter? Honest question.
Title: Re: EM Drive Developments
Post by: Cinder on 08/04/2014 03:39 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238307#msg1238307">Quote from: ChrisWilson68 on 08/03/2014 08:48 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238304#msg1238304">Quote from: Star One on 08/03/2014 08:41 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238297#msg1238297">Quote from: hop on 08/03/2014 08:19 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238285#msg1238285">Quote from: Star One on 08/03/2014 07:47 PM</a>
It seems much confusion has arisen here. I have been reading on the Polywell forums that firstly the business with the Null article is not a concern, what you are seeing is an ill chosen abstract. Please see the quote below for more detail.
If the experiments were actually done at atmospheric pressure none of that matters. It's clear from the paper that at least some of the tests were (see fig 22). That fact that it isn't clearly stated for each test is a major flaw in the paper regardless of the results, and strongly suggests the paper wasn't rigerously reviewed.

I don't understand why you think the quoted post would "clear up confusion", it looks like a hand wavy rationalization to me. To most scientists, a "null" that produces the predicted effect would be a strong hint to look for experimental error, not new physics.

My overall view is this is going to have wait for the further round of tests in the fall of this year, it looks like at this time there are just too many possible issues with this as it stands. It sounds like what they are planning next is either going to make or break this whole thing.

Nothing will ever break it.  The tests will fail to show convincing evidence of anomalous thrust, and the proponents of the various reactionless drives will come up with rationalizations for it and explain how they're working on new versions that will fix the problems.  It will continue without end.

What is "it"?  Yes it can be broken, with good enough experimental setup.  That is what science is.  If this thing (Cannae or whatever White used and/or renamed) is non-functional, and so simply non-functional, why doesn't someone else demonstrate that?

If that happened, would "they" have any credence (ie employment) at NASA? 

Title: Re: EM Drive Developments
Post by: Elmar Moelzer on 08/04/2014 03:57 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238555#msg1238555">Quote from: IslandPlaya on 08/04/2014 02:52 PM</a>
Am not sure I understand the objection to power being provided from a source not physically connected to the device.

I understand that it would no longer be a closed system, but considering the scope of the mechanism of which these things are supposed to work then it is a moot point.
Why would it matter? Honest question.
The power is provided from a physically connected source, but the source is not accelerated with the device. This means that you are feeding a current from a static system into a moving frame of reference and that could appear as a thrust. And I might be wrong with this, but I am pretty sure that this could be a potential problem, especially when we are dealing with very small amounts of thrust here.

Title: Re: EM Drive Developments
Post by: frobnicat on 08/04/2014 04:15 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238555#msg1238555">Quote from: IslandPlaya on 08/04/2014 02:52 PM</a>
Am not sure I understand the objection to power being provided from a source not physically connected to the device.

I understand that it would no longer be a closed system, but considering the scope of the mechanism of which these things are supposed to work then it is a moot point.
Why would it matter? Honest question.

Don't know the exact setup but it's not trivial to exchange power from laboratory frame to device frame without exchanging momentum down to µN. The thrust of the device is measured as a displacement against a spring. With a torsion pendulum the device should be completely free to rotate about a vertical axis save for a very weak spring restoring force. The torsion wire(s) should be the only mechanical link(s) between lab frame and device frame. If you go current through them they are heating (changing stiffness). If you have other "soft" bent wires they will exert spurious forces. Also 10 cm of straight wire passing only 200mA of current will get about a µN of lateral thrust in the earth magnetic field alone. A curved wire will tend to straighten up a little bit from interaction with its own generated magnetic field. Going wireless would probably be worse as it's basically coupling electromagnets across the two frames. Even optical power transmission has some radiation pressure (not sure how much). All effects that go on when power on and off when power off (like the effect to be measured). I'm sure all that can be mitigated, but it's really far from trivial. Better have the power source on the suspended test bed (though not perfect as it can still electromagnetically interfere with lab/earth frame even in a vacuum)
Edited : 200mA not 20mA

Title: Re: EM Drive Developments
Post by: CW on 08/04/2014 05:14 PM
I don't get it in my head, why each and every one of these experiments seems unable to just put the local power supply on the would-be drive and start the damn thing. It should be an easy task to put the test article in a non-functional mode and record possible forces, while energy is supplied for an exact duration of time. Do this a statistically relevant number of times and e.g. average the recorded data, then make the test article functional (we all wish for that, don't we) and do your real recordings, for the same time duration as for calibrating. Then do a friggin' delta, and you should pretty much know if Scotty farted in the lab or if there is some real stuff going on :) .
Title: Re: EM Drive Developments
Post by: sghill on 08/04/2014 05:41 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1237982#msg1237982">Quote from: CW on 08/02/2014 07:39 PM</a>
Hello all,

I think there is one elephant in the room that nobody seems to notice. If the drive is supposed to gain impulse by interaction with virtual particles of the quantum vacuum, then these particles obviously have to be accelerated in the opposed direction in which the drive is accelerated.

Here comes now the elephant: When those accelerated virtual particles (which pop in an out of existence spontaneously) disappear again to who-knows-where, what happens to the impulse that these particles previously gained.. is it gone? I can hardly imagine that this should be the case. So.. where would the imparted impulse on the virtual particles go? Ideas? On the other hand.. please correct me if I'm wrong.. I seem to remember some knowledge that virtual particles were not subject to impulse conservation?

Regards

Welcome to the forum!

[sophomoric speculation] Perhaps the impulse goes to wherever the virtual particles came "from" when they pop out of existence again.  Conservation of momentum only matters in a closed system right? [/sophomoric speculation]

Title: Re: EM Drive Developments
Post by: DanielW on 08/04/2014 05:55 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238603#msg1238603">Quote from: frobnicat on 08/04/2014 04:15 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238555#msg1238555">Quote from: IslandPlaya on 08/04/2014 02:52 PM</a>
Am not sure I understand the objection to power being provided from a source not physically connected to the device.

I understand that it would no longer be a closed system, but considering the scope of the mechanism of which these things are supposed to work then it is a moot point.
Why would it matter? Honest question.

Don't know the exact setup but it's not trivial to exchange power from laboratory frame to device frame without exchanging momentum down to µN. The thrust of the device is measured as a displacement against a spring. With a torsion pendulum the device should be completely free to rotate about a vertical axis save for a very weak spring restoring force. The torsion wire(s) should be the only mechanical link(s) between lab frame and device frame. If you go current through them they are heating (changing stiffness). If you have other "soft" bent wires they will exert spurious forces. Also 10 cm of straight wire passing only 20mA of current will get about a µN of lateral thrust in the earth magnetic field alone. A curved wire will tend to straighten up a little bit from interaction with its own generated magnetic field. Going wireless would probably be worse as it's basically coupling electromagnets across the two frames. Even optical power transmission has some radiation pressure (not sure how much). All effects that go on when power on and off when power off (like the effect to be measured). I'm sure all that can be mitigated, but it's really far from trivial. Better have the power source on the suspended test bed (though not perfect as it can still electromagnetically interfere with lab/earth frame even in a vacuum)

I would like to know more about the experimental set up. But what they have just sounds prone to error. They are not measuring force directly, they are measuring torque. We know that they are passing electrons through wires, but not how those wires are shaped. In a stainless steel container. I can easily think of cases that would create a small torque. induced eddy currents for example. Maybe they just got unlucky that whatever weird EM effects are going on happened to create a net torque in the same direction that they expected a force for the plane of measurement.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/04/2014 07:08 PM
I think they did the test with an RF load also.
They reported no force in this case. That must go someway to eliminating systemic errors in their setup.
Title: Re: EM Drive Developments
Post by: RanulfC on 08/04/2014 07:13 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238319#msg1238319">Quote from: IslandPlaya on 08/03/2014 09:28 PM</a>
Too important to be public. Military knows to release crappy results.
What do you think X34 is for?

Sure you want to go with that example there? The X-34 never flew and so provided NO data. Just an FYI :)

Randy

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/04/2014 07:14 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238705#msg1238705">Quote from: IslandPlaya on 08/04/2014 07:08 PM</a>
I think they did the test with an RF load also.
They reported no force in this case. That must go someway to eliminating systemic errors in their setup.

No, they reported there was some thrust detected from the RF load, also, but not as much, and they subtracted that from the measured thrust for the other two devices.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/04/2014 07:15 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238709#msg1238709">Quote from: RanulfC on 08/04/2014 07:13 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238319#msg1238319">Quote from: IslandPlaya on 08/03/2014 09:28 PM</a>
Too important to be public. Military knows to release crappy results.
What do you think X34 is for?

Sure you want to go with that example there? The X-34 never flew and so provided NO data. Just an FYI :)

Randy
Lol. Fair cop RanulfC!
I 'of course' meant to say the X-37
 :-[

Title: Re: EM Drive Developments
Post by: RanulfC on 08/04/2014 07:20 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238713#msg1238713">Quote from: IslandPlaya on 08/04/2014 07:15 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238709#msg1238709">Quote from: RanulfC on 08/04/2014 07:13 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238319#msg1238319">Quote from: IslandPlaya on 08/03/2014 09:28 PM</a>
Too important to be public. Military knows to release crappy results.
What do you think X34 is for?

Sure you want to go with that example there? The X-34 never flew and so provided NO data. Just an FYI :)

Randy
Lol. Fair cop RanulfC!
I 'of course' meant to say the X-37
 :-[

Of course you did, :) Don't forget "we" are watching you... No, really we are, now turn the light back on and open the curtain so we can get a better view...
(Did I ever mention I once had a hobby of "tweeking" the conspiricy theory boards? Loads of fun... The the Illuminatia contacted me... Yes that was a Weird Al reference! :) )

Randy

Title: Re: EM Drive Developments
Post by: CW on 08/04/2014 07:57 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238647#msg1238647">Quote from: sghill on 08/04/2014 05:41 PM</a>
Welcome to the forum!

[sophomoric speculation] Perhaps the impulse goes to wherever the virtual particles came "from" when they pop out of existence again.  Conservation of momentum only matters in a closed system right? [/sophomoric speculation]

Thanks for your welcome, sghill.

If you put it like that, it seems to me that 'existence' should comprise some weird form of (in lack of a better word) event horizon that is perhaps comparable to a mirror surface. Maybe physical reality actually takes the form of a mirrored state, while the sum of all vectors over both sides of the mirror half spaces is perfectly zero? If so, then you could even produce BS like 'free energy', because device A then existed on both sides of the mirror with exactly diametral vectors, and everything still nulls out at all times.. NASA, you can do it ::) !

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/04/2014 08:16 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238711#msg1238711">Quote from: ChrisWilson68 on 08/04/2014 07:14 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238705#msg1238705">Quote from: IslandPlaya on 08/04/2014 07:08 PM</a>
I think they did the test with an RF load also.
They reported no force in this case. That must go someway to eliminating systemic errors in their setup.

No, they reported there was some thrust detected from the RF load, also, but not as much, and they subtracted that from the measured thrust for the other two devices.
They did? Going back over the abstract they mention the RF load, but nothing about testing of such.
Did I just overlook it or do you have extra info?

Title: Re: EM Drive Developments
Post by: JasonAW3 on 08/04/2014 08:41 PM
I'm hoping that they find that this gizmo actually works, but if it doesn't, I don't think that they can accuse anyone of fraud this time.  It may be a set of honest mistakes.

I just find it danged interesting that preliminary testing shows a success, even on the rigged device that wasn't supposed to work.

It makes me wonder just what the heck have they found here anyway?
Title: Re: EM Drive Developments
Post by: brokndodge on 08/04/2014 08:50 PM
IANAS - But, I have read the report and it seems to me that they are only reporting on experimental results that they could not explain and honestly didn't expect to see.  The first set of experiments and the "null" (they should have chosen a better word) device indicated results that were unexpected and invalidated 1 theory as to why results were seen.  The so called "null" device was not really such a device. Rather, the engineer that made it had a theory that placing groves in one end of the device would create thrust and that not having the grooves would not create thrust.  He was proven wrong in that the device appeared to create thrust irregardless of the groves. 

The second set of experiments conducted with a different device of a type more closely related to the EMDrive also yielded results.  They were able to take lessons learned about their first experimental setup and apply them to the second set of tests.  As such they were able to test at much higher frequencies. 

Among all of the tests, time available to test has been an issue. They stated in the opening brief about the setup of their vacuum chamber and pendulum that it takes "days" to pull an appropriate vacuum.  Later in the paper they stated that one of the devices used had electrical components that were not vacuum friendly.  I don't recall a specific mention of the second set of tests being performed in a vacuum. 

The paper did not make any conclusions as to what is causing the effect that they are seeing.  It does state that the effect is worth investigating and that they are planning to test a more powerful 1GHz version at other facilities with better equipment.  I believe that at this time such an advanced concept lab as this is doing the right thing in further researching the results that they measured.  I also believe that they are confident to a high enough degree to warrant larger scale testing at facilities that are better equipped for such tests. 

I look forward to the results of such testing whether they be positive or negative.
Title: Re: EM Drive Developments
Post by: Star One on 08/04/2014 08:53 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238596#msg1238596">Quote from: Elmar Moelzer on 08/04/2014 03:57 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238555#msg1238555">Quote from: IslandPlaya on 08/04/2014 02:52 PM</a>
Am not sure I understand the objection to power being provided from a source not physically connected to the device.

I understand that it would no longer be a closed system, but considering the scope of the mechanism of which these things are supposed to work then it is a moot point.
Why would it matter? Honest question.
The power is provided from a physically connected source, but the source is not accelerated with the device. This means that you are feeding a current from a static system into a moving frame of reference and that could appear as a thrust. And I might be wrong with this, but I am pretty sure that this could be a potential problem, especially when we are dealing with very small amounts of thrust here.

I assume that's why they are building a more powerful setup to test.

From what I have gathered it mentions somewhere this net setup being sent out to places like the JPL to test, can anyone confirm this?

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/04/2014 08:57 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238758#msg1238758">Quote from: brokndodge on 08/04/2014 08:50 PM</a>
IANAS - But, I have read the report and it seems to me that they are only reporting on experimental results that they could not explain and honestly didn't expect to see.  The first set of experiments and the "null" (they should have chosen a better word) device indicated results that were unexpected and invalidated 1 theory as to why results were seen.  The so called "null" device was not really such a device. Rather, the engineer that made it had a theory that placing groves in one end of the device would create thrust and that not having the grooves would not create thrust.  He was proven wrong in that the device appeared to create thrust irregardless of the groves. 

The second set of experiments conducted with a different device of a type more closely related to the EMDrive also yielded results.  They were able to take lessons learned about their first experimental setup and apply them to the second set of tests.  As such they were able to test at much higher frequencies. 

Among all of the tests, time available to test has been an issue. They stated in the opening brief about the setup of their vacuum chamber and pendulum that it takes "days" to pull an appropriate vacuum.  Later in the paper they stated that one of the devices used had electrical components that were not vacuum friendly.  I don't recall a specific mention of the second set of tests being performed in a vacuum. 

The paper did not make any conclusions as to what is causing the effect that they are seeing.  It does state that the effect is worth investigating and that they are planning to test a more powerful 1GHz version at other facilities with better equipment.  I believe that at this time such an advanced concept lab as this is doing the right thing in further researching the results that they measured.  I also believe that they are confident to a high enough degree to warrant larger scale testing at facilities that are better equipped for such tests. 

I look forward to the results of such testing whether they be positive or negative.
Great post.
I may be slow today, but could you supply a link to the paper please?
Cheers mate.

Title: Re: EM Drive Developments
Post by: brokndodge on 08/04/2014 09:10 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238747#msg1238747">Quote from: IslandPlaya on 08/04/2014 08:16 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238711#msg1238711">Quote from: ChrisWilson68 on 08/04/2014 07:14 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238705#msg1238705">Quote from: IslandPlaya on 08/04/2014 07:08 PM</a>
I think they did the test with an RF load also.
They reported no force in this case. That must go someway to eliminating systemic errors in their setup.

No, they reported there was some thrust detected from the RF load, also, but not as much, and they subtracted that from the measured thrust for the other two devices.
They did? Going back over the abstract they mention the RF load, but nothing about testing of such.
Did I just overlook it or do you have extra info?

There are two sets of tests mentioned in the actual paper (not the NASA abstract).  The first set of tests were limited in power due to RF leakage from the vacuum chamber.  That set of tests was limited to 935 KHz to prevent such leakage.  Three apparatus were tested.  The first 2 were nearly identical pancake shaped devices.  The first of those those had groves cut into the inside rear face of the pancake.  The engineer believed that those grooves would cause or increase the thrust created by it.  The second did not have grooves and is the one refereed to as the null device.  The engineer believed that the absence of grooves in this version would prevent it from creating thrust.  Now, the third apparatus was a simple RF modulator and was the control.  In this first set of tests conducted in August of 13, the first 2 devices created a thrust effect that was nearly identical disproving the engineers theory.  The third (control) apparatus produced 0 thrust at the same power levels used on the first 2.

There was a second set of tests performed on a different device in early 2014.  This test used lessons learned from the first set to eliminate the RF leakage above 1MHz in the vacuum chamber.  During this test there were two apparatus.  The test apparatus and the control which was similar to the control used in the first test.  The control did create about 9.2microN of thrust.  This was determined to be caused by electromagnetic interaction with some magnets inside the vacuum chamber and was compensated for.  I don't know if it was compensated for mathematically or thru physical shielding.  They ran the test apparatus thru a range of frequencies and did achieve varying degrees of thrust that were significant compared to their control.

Title: Re: EM Drive Developments
Post by: brokndodge on 08/04/2014 09:17 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238764#msg1238764">Quote from: IslandPlaya on 08/04/2014 08:57 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238758#msg1238758">Quote from: brokndodge on 08/04/2014 08:50 PM</a>
IANAS - But, I have read the report and it seems to me that they are only reporting on experimental results that they could not explain and honestly didn't expect to see.  The first set of experiments and the "null" (they should have chosen a better word) device indicated results that were unexpected and invalidated 1 theory as to why results were seen.  The so called "null" device was not really such a device. Rather, the engineer that made it had a theory that placing groves in one end of the device would create thrust and that not having the grooves would not create thrust.  He was proven wrong in that the device appeared to create thrust irregardless of the groves. 

The second set of experiments conducted with a different device of a type more closely related to the EMDrive also yielded results.  They were able to take lessons learned about their first experimental setup and apply them to the second set of tests.  As such they were able to test at much higher frequencies. 

Among all of the tests, time available to test has been an issue. They stated in the opening brief about the setup of their vacuum chamber and pendulum that it takes "days" to pull an appropriate vacuum.  Later in the paper they stated that one of the devices used had electrical components that were not vacuum friendly.  I don't recall a specific mention of the second set of tests being performed in a vacuum. 

The paper did not make any conclusions as to what is causing the effect that they are seeing.  It does state that the effect is worth investigating and that they are planning to test a more powerful 1GHz version at other facilities with better equipment.  I believe that at this time such an advanced concept lab as this is doing the right thing in further researching the results that they measured.  I also believe that they are confident to a high enough degree to warrant larger scale testing at facilities that are better equipped for such tests. 

I look forward to the results of such testing whether they be positive or negative.
Great post.
I may be slow today, but could you supply a link to the paper please?
Cheers mate.

See below from about page 6 of this very thread.  When you follow the link you will have to skip past about 2 or 3 paragraphs of the guy discounting the results to find two links to the actual paper:

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238282#msg1238282">Quote from: hop on 08/03/2014 07:42 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238120#msg1238120">Quote from: pagheca on 08/03/2014 07:01 AM</a>
The problem is that the article linked is not a scientific paper (http://www.compoundchem.com/2014/04/02/a-rough-guide-to-spotting-bad-science), but a clearly preliminary technical report, the typical "hat on the seat" (copyrighted by me :) ) paper required to ensure to be the first IF a sensational result is confirmed in order to get an high citation index in the future.
A link to the actual paper may be found at
https://plus.google.com/117663015413546257905/posts/C7vx2G85kr4

However this is a conference paper, which in many cases aren't peer reviewed in the same way a journal paper would be. I'm not sure about this particular case.

In any case, if Baez summery is correct, there is really nothing worth talking about here... (which should be no surprise to anyone who read the original abstract)

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/04/2014 09:26 PM
Awesome. Some good night-time reading!
Thanks.
Title: Re: EM Drive Developments
Post by: hop on 08/04/2014 09:41 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238778#msg1238778">Quote from: brokndodge on 08/04/2014 09:17 PM</a>
See below from about page 6 of this very thread.  When you follow the link you will have to skip past about 2 or 3 paragraphs of the guy discounting the results to find two links to the actual paper:
On the other hand, anyone interested in the plausibility (or otherwise) of this result may find reading the post and discussion in the comments to be time well spent.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/04/2014 09:47 PM
On the gripping hand we are discussing it here.
Any insights you may have had from reading that post, please repeat here.
I have speed read the paper. Seems very thorough. Of course speed-reading is not good. But at the moment I think they have found something.
Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/04/2014 10:11 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238747#msg1238747">Quote from: IslandPlaya on 08/04/2014 08:16 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238711#msg1238711">Quote from: ChrisWilson68 on 08/04/2014 07:14 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238705#msg1238705">Quote from: IslandPlaya on 08/04/2014 07:08 PM</a>
I think they did the test with an RF load also.
They reported no force in this case. That must go someway to eliminating systemic errors in their setup.

No, they reported there was some thrust detected from the RF load, also, but not as much, and they subtracted that from the measured thrust for the other two devices.
They did? Going back over the abstract they mention the RF load, but nothing about testing of such.
Did I just overlook it or do you have extra info?

From reply #88 in this thread:

<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238285#msg1238285">Quote from: Star One on 08/03/2014 07:47 PM</a>
Quote
We're talking of net thrust because of course the setup was also tested with a null 50 ohm load connected, in order to cancel the effect from the drives and detect any detect any spurious force due to EM coupling with the whole apparatus (which exists, at 9.6 µN) and this "null" spurious force was evidently subtracted from any thrust signal due to the drives then tested on the pendulum.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/04/2014 10:17 PM
Yes. I have the paper now to check for myself.
Thanks anyway
Title: Re: EM Drive Developments
Post by: Star One on 08/04/2014 10:26 PM
To say there is a lot of scepticism on that link is an understatement.
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/04/2014 10:43 PM
I think in these things we have to be very careful.
There are two camps:-
1) People who would very much like it to be true.
2) People who say it is (obviously) impossible.

I would put myself in (1) but that doesn't mean I wouldn't except hard results disproving the effect.
Anyway, whichever camp you are in, it pays to be objective and not succumb to confirmation bias.
It can be difficult to do this, but we must try...
Title: Re: EM Drive Developments
Post by: Star One on 08/04/2014 10:48 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=35315.msg1238819#msg1238819">Quote from: IslandPlaya on 08/04/2014 10:43 PM</a>
I think in these things we have to be very careful.
There are two camps:-
1) People who would very much like it to be true.
2) People who say it is (obviously) impossible.

I would put myself in (1) but that doesn't mean I wouldn't except hard results disproving the effect.
Anyway, whichever camp you are in, it pays to be objective and not succumb to confirmation bias.
It can be difficult to do this, but we must try...

Excellent post. I would say I am now of the same view as you on this topic.

Title: Re: EM Drive Developments
Post by: FlyingMoose on 08/05/2014 07:21 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238122#msg1238122">Quote from: Silversheep2011 on 08/03/2014 07:22 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238098#msg1238098">Quote from: FlyingMoose on 08/03/2014 04:43 AM</a>

This discovery came about because Shawyer was trying to explain the thrust generated by the microwave transmitters on satellites which exceeded what was expected and required additional fuel to correct.

This would really make an interesting subject to read or a comparison point to read up on.
who you be able to supply a link or a paper?

I have spent about 5 hours and have been unable to find it again.  Google is worthless because any keywords I can think of only find hundreds of news articles about the recent NASA experiment.  It was a mention in a forum, it wasn't an official paper.  Perhaps someone with better google-fu can find it.

Title: Re: EM Drive Developments
Post by: sghill on 08/05/2014 07:34 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238021#msg1238021">Quote from: ChrisWilson68 on 08/02/2014 10:00 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238016#msg1238016">Quote from: Star One on 08/02/2014 09:21 PM</a>
You might want to be rather careful in what you say here otherwise it might look like you're casting aspersions on the NASA scientists and their decision to investigate this.

This is one little corner of NASA.  NASA is a huge organization with lots and lots of people working on lots of things.  Sonny White and friends are not equivalent to NASA as a whole.

And there's nothing wrong with complaining that this one small part of NASA is wasting precious resources that could be better spent, and misleading the public by letting the NASA name get attached to wishful thinking in the guise of science.

Consider this.  Eagleworks is trying to get their inferometer apparatus up and running, and learn how to use it properly for their own proposed warp bubble and Q-thruster experiments.  This experiment- who cares if it's quackery or not- gave them a perfect chance to try out their methods on a completely 3rd party apparatus.  That, in turn, allows them to refine their methods for their own experiments.

If the EMDrive theories are valid, then so much the better.  It still worked to Eagleworks- and NASA's advantage to go through the testing motions without drinking the EMDrive Kool Aid.  The fact that the released paper focused on the testing procedures reinforces this theory IMHO.  Also, I think the soundness of Eagleworks performing this testing is further reinforced by the fact that the test article also generated thrust, so there were possibly problems (again IMHO) in their procedures that this testing exposed.

In other words, it's better for them to report false positives with the EMDrive thruster than their own Q-thruster right?!? :)

Title: Re: EM Drive Developments
Post by: Star One on 08/05/2014 08:48 PM
A rather bizarre argument has blown up on this over at the Polywell forums on the main thread, I am not going to clog this forum with it but it did leave me rather scratching my head. I don't think I've known any other recent scientific story that's attracted such odd commentary, it's made me despair of whole chunks of the internet.:) This forum is a positive oasis of sanity.
Title: Re: EM Drive Developments
Post by: aero on 08/05/2014 08:51 PM
In case it hasn't been posted, the full AIAA paper is available here:

http://www.scribd.com/doc/235868930/Anomalous-Thrust-Production-from-an-RF-Test-Device-Measured-on-a-Low-Thrust-Torsion-Pendulum (http://www.scribd.com/doc/235868930/Anomalous-Thrust-Production-from-an-RF-Test-Device-Measured-on-a-Low-Thrust-Torsion-Pendulum)

A quick scan discovered the interesting item, that not two, but four devices were tested and reported. Three resulted in force being measured repeatably. Two devices were the disk shaped Cannae device, one of which was designed for null results but produced force anyway, one device was the Eagelworks in-house design, a conical shaped device similar the original Roger Shawyer and the chinese devices and the fourth device was a brick shaped RF load. It did not produce thrust.

So what we have is at least 5 devices which have been reported as producing thrust, and at least 3 different test set-ups that have been blamed as being faulty by the blogger community, each with a different fault. To me, it seems time to apply Occam's razor.

It is easy to show that the undetected flaw which the EagleWorks Lab is accused of, would not have gone undetected at the Chinese high power test. The suspected flaw is force resulting from heating and convective air flow. But in the Chinese high power test in order for this mechanism to give the measured force, the mass of air flow (mdot)  times the change in air velocity (Ve) must equal the measured force. But that air flow would be easily detected by anyone who casually glanced at the operating device. So the flaw is different for different test set-ups.

So in the end, there can be either a different flaw for each test set-up, or there can be one unknown but reproducible force generating mechanism. What does Occam's razor say?
Title: Re: EM Drive Developments
Post by: aero on 08/05/2014 08:57 PM
If you want to see bizarre, go here:

http://www.physforum.com/index.php (http://www.physforum.com/index.php)

But this is a hot blogger topic world wide, I checked a French and Czech blog site (Google Translate) and they seem to be very hard over on this subject, too. Most bloggers seem to behave as though they fear that the EM drive will steal their women and destroy their sex life.
Title: Re: EM Drive Developments
Post by: Star One on 08/05/2014 09:12 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1239844#msg1239844">Quote from: aero on 08/05/2014 08:57 PM</a>
If you want to see bizarre, go here:

http://www.physforum.com/index.php (http://www.physforum.com/index.php)

But this is a hot blogger topic world wide, I checked a French and Czech blog site (Google Translate) and they seem to be very hard over on this subject, too. Most bloggers seem to behave as though they fear that the EM drive will steal their women and destroy their sex life.

See my post above I have genuinely been concerned by some of the commentary related to this I've read.

Title: Re: EM Drive Developments
Post by: GregA on 08/05/2014 10:33 PM
Guys I applaud trying to stay on topic, but you're giving so little detail I have no idea what you're talking about. Going to that site shows some terrible "scientific" thoughts, is that what you mean.

Perhaps it needs a separate thread on "misunderstanding science" or whatever the concern is - otherwise an illustration of your concern would be great :)
Title: Re: EM Drive Developments
Post by: aero on 08/05/2014 11:29 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1239888#msg1239888">Quote from: GregA on 08/05/2014 10:33 PM</a>
Guys I applaud trying to stay on topic, but you're giving so little detail I have no idea what you're talking about. Going to that site shows some terrible "scientific" thoughts, is that what you mean.

Perhaps it needs a separate thread on "misunderstanding science" or whatever the concern is - otherwise an illustration of your concern would be great :)

A problem with blogging about EM Drive is this: There are no theoretical underpinnings to the experimental devices. That means that there is no means to evaluate the experiment performed relative to the underlying theory since there isn't any. Well, that's not quite true, there are home grown ideas of a theory for each experimenter, but no theory that is accepted outside its own laboratory. Some of the theories seem laughable and some of them have been proven to be wrong.

The situation as it stands currently is that the general blogger community spends their creative energy trying to imagine a flaw in the experiments which would give the measured results. Of course flaws can be imagined and theories can be laughed at, but doing so does not advance scientific knowledge, and worse, such possible flaws are advanced very loudly without benefit of understanding the published papers which in some cases clearly describe actions taken by the experimenter to avoid such flaws.

It seems that the widely held belief is "If it is not explained by the Standard Model, then it is not physics."

What I had hoped is that some knowledgeable people would propose an idea for a theory that could then be massaged by the community into something worthy of consideration. Instead what I have found is that when a germ of an idea is presented the response is, along the lines of, "There was no force, it was a deflection of a spring which could have been caused by ...(this or that reason). Engineers can't do science, only scientists can do science." In the end, the experimenters are commonly accused of holding their thumbs on the scales.

But that is just my observation. There are several papers about EM Drive available on the internet, including the NASA paper I linked above. Read the full paper, not just the abstract, then check some of the blog sites around the net. I think you will see the lack of rational thought for yourself.

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/06/2014 02:58 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1239840#msg1239840">Quote from: aero on 08/05/2014 08:51 PM</a>
In case it hasn't been posted, the full AIAA paper is available here:

http://www.scribd.com/doc/235868930/Anomalous-Thrust-Production-from-an-RF-Test-Device-Measured-on-a-Low-Thrust-Torsion-Pendulum (http://www.scribd.com/doc/235868930/Anomalous-Thrust-Production-from-an-RF-Test-Device-Measured-on-a-Low-Thrust-Torsion-Pendulum)

A quick scan discovered the interesting item, that not two, but four devices were tested and reported. Three resulted in force being measured repeatably. Two devices were the disk shaped Cannae device, one of which was designed for null results but produced force anyway, one device was the Eagelworks in-house design, a conical shaped device similar the original Roger Shawyer and the chinese devices and the fourth device was a brick shaped RF load. It did not produce thrust.

So what we have is at least 5 devices which have been reported as producing thrust, and at least 3 different test set-ups that have been blamed as being faulty by the blogger community, each with a different fault. To me, it seems time to apply Occam's razor.

It is easy to show that the undetected flaw which the EagleWorks Lab is accused of, would not have gone undetected at the Chinese high power test. The suspected flaw is force resulting from heating and convective air flow. But in the Chinese high power test in order for this mechanism to give the measured force, the mass of air flow (mdot)  times the change in air velocity (Ve) must equal the measured force. But that air flow would be easily detected by anyone who casually glanced at the operating device. So the flaw is different for different test set-ups.

So in the end, there can be either a different flaw for each test set-up, or there can be one unknown but reproducible force generating mechanism. What does Occam's razor say?

The proper question to ask of Occam's razor whether it's more likely that three small groups made mistakes in their test setups that gave them the results they desperately wished to see, or that tens of thousands of physicists working over decades completely failed to find an effect that is easy to produce on a variety of different devices that are simple to make.

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/06/2014 03:02 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1239905#msg1239905">Quote from: aero on 08/05/2014 11:29 PM</a>
Of course flaws can be imagined and theories can be laughed at, but doing so does not advance scientific knowledge

If there is a good reason to suspect an experimental flaw, pointing out that reason and spreading the idea about that flaw does absolutely advance scientific knowledge.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/06/2014 04:20 AM
without knowledge; such a thing may be equivalent to shouting "Swamp Gas!" at every unknown areal phenomenon though. it may be that it's not Swamp Gas; It Could be Venus! or a illumination flare. a person that reflexively hollers swamp gas isn't advancing science. whether it really is a LGM or if it turns out to be any explanation other than swamp gas. the swamp gas camp does a diservice if it is really Venus and they didn't bother to check things out. the real thing remains unknown if the debunking is via the critic's own bunkum.
Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/06/2014 04:28 AM
I was replying to an unqualified statement with a qualified statement.  The unqualified statement I was replying to said that claiming flaws does not advance science.  My reply was qualified, to point out that in some cases it does.
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/06/2014 04:33 AM
I see. I missed that. My mistake.
Title: Re: EM Drive Developments
Post by: aero on 08/06/2014 04:37 AM

Quote
The proper question to ask of Occam's razor whether it's more likely that three small groups made mistakes in their test setups that gave them the results they desperately wished to see, or that tens of thousands of physicists working over decades completely failed to find an effect that is easy to produce on a variety of different devices that are simple to make.

No. The proper question to ask of Occam's razor whether it's more likely some large number of the tens of thousands of physicists working over decades are righteously offended after completely failing to investigate an unknown effect that is easy to produce on a variety of different devices that are simple to make after one man stumbled across that effect and three small groups reproduced it, or if the effect could in fact be real.

Title: Re: EM Drive Developments
Post by: aero on 08/06/2014 04:54 AM

Quote
If there is a good reason to suspect an experimental flaw, pointing out that reason and spreading the idea about that flaw does absolutely advance scientific knowledge.

While that is true, it is also true that the main reason to suspect an experimental flaw is that posters don't understand how the device could work as claimed. Now this may be a good reason, but I don't think so. No one knows everything. I have suggested that a better way to advance science would be to propose a germ of an idea that could maybe explain the phenomena for further development by the crowd. Crowd sourced science.

Of course it is hard to propose an idea because doing so sets the proposer up as the butt of the criticism that is currently aimed at the experimenters. What sane person would eagerly step into that line of fire? In order for crowd sourced science to work, the thread would need a strong and heavy handed moderator, with name calling an absolute "no-no."

Title: Re: EM Drive Developments
Post by: aero on 08/06/2014 07:54 AM

I just finished reviewing the full AIAA paper that NASA submitted. There are several very interesting details once you get into the meat of it. One thing in particular was this:

Quote
There appears to be a clear dependency between thrust magnitude and the presence of some sort of dielectric RF resonator in the thrust chamber. The geometry, location, and material properties of this resonator must be evaluated using numerous COMSOL® iterations to arrive at a viable thruster solution. We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust.

I don't know what it means, but it says that they took out one little piece and that little piece proved to be critical to producing thrust.

Of course I guess that little piece could have been central to the "experimental error."

What is a dielectric RF resonator and what is it used for?

Another point of interest is that that COMSOL® computer program they have seems to predict the thrust produced to quite high fidelity. I guess the computer program must have a built in "experimental error" bias.

Read the paper people, quit fooling yourselves with second hand information.

Title: Re: EM Drive Developments
Post by: MP99 on 08/06/2014 09:17 AM



<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1239804#msg1239804">Quote from: FlyingMoose on 08/05/2014 07:21 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238122#msg1238122">Quote from: Silversheep2011 on 08/03/2014 07:22 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1238098#msg1238098">Quote from: FlyingMoose on 08/03/2014 04:43 AM</a>

This discovery came about because Shawyer was trying to explain the thrust generated by the microwave transmitters on satellites which exceeded what was expected and required additional fuel to correct.

This would really make an interesting subject to read or a comparison point to read up on.
who you be able to supply a link or a paper?

I have spent about 5 hours and have been unable to find it again.  Google is worthless because any keywords I can think of only find hundreds of news articles about the recent NASA experiment.  It was a mention in a forum, it wasn't an official paper.  Perhaps someone with better google-fu can find it.

Sounds like this may be of some use, then, to weed out the new news:-

http://www.quora.com/Can-I-restrict-Google-searches-by-a-date-range

Cheers, Martin

Title: Re: EM Drive Developments
Post by: Darkseraph on 08/06/2014 09:33 AM
I suppose the question to ask next is, Has NASA finally invented a thruster that finally defies Betterridge's Law of Headlines?


Color me skeptical after Flesichmann-Ponns, OPERA...

Great if it was true (or terrifying considering the inevitable military applications) but I will wait a while this blows over and see if it sticks.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/06/2014 01:55 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1237967#msg1237967">Quote from: SteveKelsey on 08/02/2014 06:46 PM</a>
I step into this debate with trepidation. My perspective is that neither proponent has developed a successful characterisation of any effect...

Pretty much Bingo, I'd say.  Still, I think that NASA is correct to offer them the opportunity to test.  From:

http://ntrs.nasa.gov/search.jsp?R=20140006052

Quote
Financial Sponsor: NASA Johnson Space Center; Houston, TX, United States

I imagine that NASA spent an appropriate sum on this testing.  There has to be some official acknowledgement that these people are attempting to validate a theory, and they do need a place to set up the experiment.  I also noted the results for the null article.

The commentary on the intertubes site that I read is, well, inspiring and informative:

This is strangely arousing. (http://sploid.gizmodo.com/nasa-reveals-new-impossible-engine-can-change-space-t-1614549987)

Sabina's yoga class is at 5:30 this afternoon.  Sadly, I guess, neither strange nor arousing, nor dismissive of the laws of physics.  You can't get into a pose that you can't get into.

Quote from: Steve Kelsey
A rocket motor utilises the shape of the nozzle to convert chemical energy to a directed force, which we call thrust. Is it possible that all that happening here is microwave energy is converted to thrust by the shape of the chamber?

They never photograph the "other end" of the "nozzle".  I do not believe that it is open.  No matter is expected to be expelled from the thought to be open end of the nozzle.  The device is expected to move without expelling matter.

In essence, they claim to be able to convert electricity to microwaves to forward momentum.

Image found at:

http://www.scribd.com/doc/235868930/Anomalous-Thrust-Production-from-an-RF-Test-Device-Measured-on-a-Low-Thrust-Torsion-Pendulum

Title: Re: EM Drive Developments
Post by: Star One on 08/06/2014 02:17 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240108#msg1240108">Quote from: Darkseraph on 08/06/2014 09:33 AM</a>
I suppose the question to ask next is, Has NASA finally invented a thruster that finally defies Betterridge's Law of Headlines?


Color me skeptical after Flesichmann-Ponns, OPERA...

Great if it was true (or terrifying considering the inevitable military applications) but I will wait a while this blows over and see if it sticks.

What military applications, I could see you could produce a very stealthy air vehicle through it but what else?

Updated article based on the full paper.

http://nextbigfuture.com/2014/08/full-nasa-cannae-drive-and-emdrive-test.html

@JohnFornaro

What is they say extraordinary claims need extraordinary evidence to back them up.

Title: Re: EM Drive Developments
Post by: Elmar Moelzer on 08/06/2014 03:02 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240209#msg1240209">Quote from: Star One on 08/06/2014 02:17 PM</a>
What military applications, I could see you could produce a very stealthy air vehicle through it but what else?
As you say, stealth is one thing, the other is endurance. With solar cells, this thing could stay aloft for a long time, provided it really works as advertised...

Title: Re: EM Drive Developments
Post by: DMeader on 08/06/2014 04:36 PM
From xkcd:
(quantum_vacuum_virtual_plasma.png)
Title: Re: EM Drive Developments
Post by: frobnicat on 08/06/2014 06:16 PM
Back of the envelope rough order of magnitude basic physics principles sanity check :

Let's call L the thrust to power ratio (all SI)
For recall L for physically accepted photon rocket is 1/c = 3e-9 N/W
Cannae cavities tests claim about (order of magnitude) 1µN/W = 1e-6 N/W
Based on the Chinese experiments and their (empiric ?) formulas they expect possibility about 1N/kW = 1e-3 N/W

( I wonder on the nearly 3 orders of magnitude better results of Chinese ... why couldn't they try to replicate the exact same setup, even lower power as thrust would scale linearly or are there expected non linearities with power density ? )

On a given inertial frame a ship of mass M that goes from speed V to speed V+dV in a small time step dt will gain a kinetic energy dE=1/2 M (V²+2VdV+dV² - V²)=MVdV (discarding second order). That's a received power (in kinetic energy form in the given inertial frame) Pr = dE/dt = MVdV/dt = MVa = MVF/M = VF  ( where F is the thrust and a=F/M is the acceleration of the ship)
Pu is power used by the EM drive : L=F/Pu  or F=LPu, replacing F in above result : Pr=VLPu and finally Pr/Pu=VL

If the ship speed V is faster than Vf=1/L on any given inertial frame then it is now gaining more kinetic energy (relative to this arbitrary frame) than it is spending from its onboard generator. For a photon rocket Vf = c, nice because any arbitrary frame wont get you there.
For the tested and expected devices Vf goes from (again very roughly) 1000 km/s (Cannae) to 1km/s (about Chinese claims and what get them to Saturn in 9 Months straight, or rather  2.5km/s given 0.4 N/kW)

That is IF this L ratio wont depend on some absolute reference frame... So you are not only pushing on a medium that conveniently is always harvested at 0 speed relative to your ship, by doing so you are gaining more energy than spending as soon as above a very modest speed (relative to whatever ground), effectively pumping into the zero point vacuum. They even seem to hope for L=4N/kW, that's a Vf of 250m/s, that's slow enough to be mounted around a rotor : compact free energy generator ! Is this consequence seriously addressed by the Q-thruster theorists ?

If the L ratio depend on some absolute reference frame then the effect would be of lower magnitude when approaching those speeds relative to this frame. Back to aether problems : locally anchored to nearest massive body ? Else the effect would depend on orientation (Michelson-Morley...)

Vf stands for "Velocity of free energy", or "Velocity fishy"

Title: Re: EM Drive Developments
Post by: SteveKelsey on 08/06/2014 07:32 PM
I agree with aero the report is worth a careful read. Much of the critique on this thread is answered.
The parts of the report that struck me as being  interesting are:-

There were four test elements

1)   A Shawyer based truncated cone design ( There are images of the closed end in the report John F : ) )
2)   A Cannae Test component with slots
3)   A Cannae test component without slots
4)   A Null test component consisting of a 50 ohm resistive load

The Null test article was useful in identifying a 9.6  micronewton force due to a 5.6 amp current running in the DC supply cable. This Null Force’ was subtracted from the results.

It is reported that the torsion balance can measure down to 1 micronewton

The test protocol included pre and post test calibrations of the balance for each run

Of the four items tested  the 50 ohm load did not produce a force

All of the three test articles, including the Cannae test article without slots  which was anticipated would NOT produce a thrust , produced thrusts well above the sensitivity limit of the balance.

The dielectric does seem to be significant.

It is also clear that this report is part of an ongoing program and the next step is to test at higher power and in a hard vacuum.

Not what I expected, and interesting.

It may still be the result of a test protocol anomaly but there is reason to continue.
Title: Re: EM Drive Developments
Post by: Star One on 08/06/2014 08:14 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1239888#msg1239888">Quote from: GregA on 08/05/2014 10:33 PM</a>
Guys I applaud trying to stay on topic, but you're giving so little detail I have no idea what you're talking about. Going to that site shows some terrible "scientific" thoughts, is that what you mean.

Perhaps it needs a separate thread on "misunderstanding science" or whatever the concern is - otherwise an illustration of your concern would be great :)

See link below.

http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=5469

Make of what is posted in there what you will.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/06/2014 08:29 PM
Am proud to be part of the Interesting Times Gang (Thanks Mr Banks.)
I really am intrigued to see the scientific method working properly here (not the blogosphere.) We will see hopefully sooner rather than later what is going on.
 ;D
Title: Re: EM Drive Developments
Post by: Space OurSoul on 08/06/2014 08:37 PM
XKCD weighs in:

http://xkcd.com/1404/ (http://xkcd.com/1404/)
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/06/2014 08:40 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240334#msg1240334">Quote from: Star One on 08/06/2014 08:14 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1239888#msg1239888">Quote from: GregA on 08/05/2014 10:33 PM</a>
Guys I applaud trying to stay on topic, but you're giving so little detail I have no idea what you're talking about. Going to that site shows some terrible "scientific" thoughts, is that what you mean.

Perhaps it needs a separate thread on "misunderstanding science" or whatever the concern is - otherwise an illustration of your concern would be great :)

See link below.

http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=5469

Make of what is posted in there what you will.
Just speed-read that thread. Isn't GIThruster someone who was banned from NSF back-in-the-day before my time here? What was the score with him? (I can probably guess..)
I'm glad to be with sensible people who can discuss this properly here at NSF.

Title: Re: EM Drive Developments
Post by: Star One on 08/06/2014 09:04 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240344#msg1240344">Quote from: IslandPlaya on 08/06/2014 08:40 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240334#msg1240334">Quote from: Star One on 08/06/2014 08:14 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1239888#msg1239888">Quote from: GregA on 08/05/2014 10:33 PM</a>
Guys I applaud trying to stay on topic, but you're giving so little detail I have no idea what you're talking about. Going to that site shows some terrible "scientific" thoughts, is that what you mean.

Perhaps it needs a separate thread on "misunderstanding science" or whatever the concern is - otherwise an illustration of your concern would be great :)

See link below.

http://www.talk-polywell.org/bb/viewtopic.php?f=10&t=5469

Make of what is posted in there what you will.
Just speed-read that thread. Isn't GIThruster someone who was banned from NSF back-in-the-day before my time here? What was the score with him? (I can probably guess..)
I'm glad to be with sensible people who can discuss this properly here at NSF.

Much appreciate the background info and I apologise if people think the thread was inappropriate as a result, I would say in my defence I didn't know he had a known NSF history.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/06/2014 09:11 PM
I really don't know about him/her. Maybe someone who has been here longer can elucidate?
I seem to remember a thread title being "....... (GIThruster, now banned.)....."
Anyway, it doesn't really matter. The thread you linked was interesting but was more full of vitriol than science and reason. IMHO
Title: Re: EM Drive Developments
Post by: Star One on 08/06/2014 09:20 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240371#msg1240371">Quote from: IslandPlaya on 08/06/2014 09:11 PM</a>
I really don't know about him/her. Maybe someone who has been here longer can elucidate?
I seem to remember a thread title being "....... (GIThruster, now banned.)....."
Anyway, it doesn't really matter. The thread you linked was interesting but was more full of vitriol than science and reason. IMHO

I didn't like the personal vitriol posted in it but felt the thread illustrated what I was talking about last night as regards some of the extreme responses to this particular topic.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/06/2014 09:24 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240381#msg1240381">Quote from: Star One on 08/06/2014 09:20 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240371#msg1240371">Quote from: IslandPlaya on 08/06/2014 09:11 PM</a>
I really don't know about him/her. Maybe someone who has been here longer can elucidate?
I seem to remember a thread title being "....... (GIThruster, now banned.)....."
Anyway, it doesn't really matter. The thread you linked was interesting but was more full of vitriol than science and reason. IMHO

I didn't like the personal vitriol posted in it but felt the thread illustrated what I was talking about last night as regards some of the extreme responses to this particular topic.
Apologies to all if I missed stuff. I tend to speed-read things.
Bad habit I know.

Title: Re: EM Drive Developments
Post by: Raj2014 on 08/06/2014 09:26 PM
What is the latest news on the EM drive/Cannae drive? I have found a website saying that NASA did not validate the test, http://blogs.discovermagazine.com/outthere/2014/08/06/nasa-validate-imposible-space-drive-word/#.U-KZq4BdUdg. I hope this is not true and that there will be more tests done proving this method of propulsion does work.
Title: Re: EM Drive Developments
Post by: Star One on 08/06/2014 09:31 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240389#msg1240389">Quote from: Raj2014 on 08/06/2014 09:26 PM</a>
What is the latest news on the EM drive/Cannae drive? I have found a website saying that NASA did not validate the test, http://blogs.discovermagazine.com/outthere/2014/08/06/nasa-validate-imposible-space-drive-word/#.U-KZq4BdUdg. I hope this is not true and that there will be more tests done proving this method of propulsion does work.

Maybe I misread but that appears to be yet another article based on the abstract and not the full paper. If it is the writer has erred.

Title: Re: EM Drive Developments
Post by: aero on 08/06/2014 09:50 PM
Yea. The latest news is that bloggers are still writing without reading. There is one blogger who has evidently read the full paper but I'll need to find the link again. Let me refer you to the full paper in the mean time.

http://www.scribd.com/doc/235868930/Anomalous-Thrust-Production-from-an-RF-Test-Device-Measured-on-a-Low-Thrust-Torsion-Pendulum (http://www.scribd.com/doc/235868930/Anomalous-Thrust-Production-from-an-RF-Test-Device-Measured-on-a-Low-Thrust-Torsion-Pendulum)

Looking at the paper it is easy to see why people might skim through it. It is 20 pages and dry reading, but it has several nuggets in it. The full paper explains many of the misunderstandings that come from reading the widely available abstract and leaves a much more positive impression. IMO

Here is the link to the article in Next Big Future that I alluded to.

http://nextbigfuture.com/2014/08/full-nasa-cannae-drive-and-emdrive-test.html (http://nextbigfuture.com/2014/08/full-nasa-cannae-drive-and-emdrive-test.html)
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/06/2014 10:39 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240403#msg1240403">Quote from: aero on 08/06/2014 09:50 PM</a>
Yea. The latest news is that bloggers are still writing without reading. There is one blogger who has evidently read the full paper but I'll need to find the link again. Let me refer you to the full paper in the mean time.

http://www.scribd.com/doc/235868930/Anomalous-Thrust-Production-from-an-RF-Test-Device-Measured-on-a-Low-Thrust-Torsion-Pendulum (http://www.scribd.com/doc/235868930/Anomalous-Thrust-Production-from-an-RF-Test-Device-Measured-on-a-Low-Thrust-Torsion-Pendulum)

Looking at the paper it is easy to see why people might skim through it. It is 20 pages and dry reading, but it has several nuggets in it. The full paper explains many of the misunderstandings that come from reading the widely available abstract and leaves a much more positive impression. IMO

Here is the link to the article in Next Big Future that I alluded to.

http://nextbigfuture.com/2014/08/full-nasa-cannae-drive-and-emdrive-test.html (http://nextbigfuture.com/2014/08/full-nasa-cannae-drive-and-emdrive-test.html)
I read that. A good summary but not much else. (Unless I am missing something, entirely possible.)
Comments are par for the course.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/06/2014 10:46 PM
For what it's worth I speed-read a lot of things and I'm good at it.
I am still going over the NASA paper properly.
So far I think that they have been very careful about outside influences.
Ion wind, heat based stuff not so much... I will continue pouring over it.
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/06/2014 10:49 PM
Think they need a mu-metal shield already.  :(
Title: Re: EM Drive Developments
Post by: Star One on 08/06/2014 10:51 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240425#msg1240425">Quote from: IslandPlaya on 08/06/2014 10:46 PM</a>
For what it's worth I speed-read a lot of things and I'm good at it.
I am still going over the NASA paper properly.
So far I think that they have been very careful about outside influences.
Ion wind, heat based stuff not so much... I will continue pouring over it.

How about testing in hard vacuum with a Tesla cage around it?

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/06/2014 10:55 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240430#msg1240430">Quote from: Star One on 08/06/2014 10:51 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240425#msg1240425">Quote from: IslandPlaya on 08/06/2014 10:46 PM</a>
For what it's worth I speed-read a lot of things and I'm good at it.
I am still going over the NASA paper properly.
So far I think that they have been very careful about outside influences.
Ion wind, heat based stuff not so much... I will continue pouring over it.

How about testing in hard vacuum with a Tesla cage around it?
Yes, but that would be difficult and expensive! How about testing on the ISS with a Faraday cage (I'm sure you meant this!) and mu-metal components?
I agree

Title: Re: EM Drive Developments
Post by: bubbagret on 08/06/2014 10:55 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240430#msg1240430">Quote from: Star One on 08/06/2014 10:51 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240425#msg1240425">Quote from: IslandPlaya on 08/06/2014 10:46 PM</a>
For what it's worth I speed-read a lot of things and I'm good at it.
I am still going over the NASA paper properly.
So far I think that they have been very careful about outside influences.
Ion wind, heat based stuff not so much... I will continue pouring over it.

How about testing in hard vacuum with a Tesla cage around it?

You mean Faraday cage supposedly...

Title: Re: EM Drive Developments
Post by: GregA on 08/06/2014 10:57 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240403#msg1240403">Quote from: aero on 08/06/2014 09:50 PM</a>
Here is the link to the article in Next Big Future that I alluded to.

http://nextbigfuture.com/2014/08/full-nasa-cannae-drive-and-emdrive-test.html (http://nextbigfuture.com/2014/08/full-nasa-cannae-drive-and-emdrive-test.html)
Thanks for showing what you didn't like about the commentary. And this link!

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/06/2014 11:00 PM
doesn't Woodward do that with his version of this thing?  i seem to remember that in one of the many Woodward videos i have seen. if i remember correctly his unit has an integral Faraday cage and then that plexigrass cylinder is a vacuum chamber. the device is put on a torsion balance inside the vacuum chamber thing.
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/06/2014 11:23 PM
interview for woowoo type science fringey newszine. but has picture of his test chamber and his thrust traces, thermal traces and so forth. his claim is for 40 mg and 50mgs of thrust signal:

http://www.frequency.com/video/mach-effect-warp-drives-stargates-by-jim/166119888/-/5-905277

Dr Woodward chokes trying to stifle a laugh at a question the interviewer asks:

https://www.youtube.com/watch?v=tIvtnh1awFQ

Woodward giving a talk at a non woowoo space conference:

https://www.youtube.com/watch?v=hn8hqX9JBOE
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/06/2014 11:53 PM
We need more than this Stormbringer.
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/06/2014 11:57 PM
i know. i am missing a video somewhere and iam looking for the one where Woodward himself give the explanation of his set up including the contacts on his torsion balance and stuff. i am trying to find it. but meanwhile Dr Woodward's web page has links to his papers and stuff:

http://physics.fullerton.edu/~jimw/

I'm still looking for that video. i know i watched just a couple of weeks ago. :(

still can't find the video. still looking however here is Dr Paul March's PPT presentation slides. there are several good pictures of his device and charts and test rigs from 2003.

http://www.powershow.com/view1/f70a5-ZDc1Z/Paul_March_powerpoint_ppt_presentation
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/07/2014 12:00 AM
You could have Ernst Mach himself argue the current state-of-the-art.
It wouldn't make any difference.
We just don't know.
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/07/2014 12:10 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240461#msg1240461">Quote from: IslandPlaya on 08/07/2014 12:00 AM</a>
You could have Ernst Mach himself argue the current state-of-the-art.
It wouldn't make any difference.
We just don't know.

that's not important. what is important is his set up details and his results. both of which i can show with what i am putting up and with that video if i can find it.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/07/2014 02:02 AM
i still have not found it if someone could help me out in finding it I'd appreciate it. 'Cos i now want to download it to my hard drive so i don't lose it again as well as to link or embed it here.

In the video i have in mind he pointed to and covered all the components going into detail on the Faraday cage the ceramic stack, the mounting block for the stack, the balance pivot there were two rather big wire ribbon wrapped cables mounted to the pivot and leading off towards the stack itself. He explained how the type of contact s were important because they had to be forceless. he then spoke about how the stack produced a thrust signal but wore out and "died" he then showed the traces for thermal and thrust and i think two other traces (maybe power and something else) and showed where in the data traces the device died.
Title: Re: EM Drive Developments
Post by: aero on 08/07/2014 04:20 AM
Getting back to EM Drive, am I correct in thinking that the higher the frequency the more power consumed and the smaller the RF resonator?

I'm trying to guess how large a mature EM Drive might be physically? (Assuming that it does mature.) I'm pretty sure that the power sources would be a lot bigger than the EM Drive itself.

From what I've read it doesn&##039;t look like there is any reason to hang the drives off the tail end of the spaceship, rather just set them in the electronics bay, or maybe in the Captain's cabin. Of course they would need to be attached to a thrust structure. If you wanted redundancy you could just weld 20 or so of the 5% sized EM Drives on the stern of your spaceship.

I'm hoping that by the end of the year we can start speculating configurations in earnest.
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/07/2014 04:34 AM
well don't overlook another possibility. if these things work the final form might not be a single big device or set of big devices. the final form might be thousands (or millions) of tiny ones in some sort of array :) a drive on a chip.
Title: Re: EM Drive Developments
Post by: aero on 08/07/2014 05:13 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240518#msg1240518">Quote from: Stormbringer on 08/07/2014 04:34 AM</a>
well don't overlook another possibility. if these things work the final form might not be a single big device or set of big devices. the final form might be thousands (or millions) of tiny ones in some sort of array :) a drive on a chip.

Yes, they could be pretty small but the size of the resonance cavity is driven by the frequency of the RF power. At 2 GHz the cavity is about 7 cm x 3.5 cm (length doesn't matter) and working with higher frequencies gets more challenging. But that's all I know about that.

Title: Re: EM Drive Developments
Post by: GregA on 08/07/2014 05:25 AM
Yes, every floor could have them, which alters the structural strengthening needed.
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/07/2014 05:48 AM
But if the driver freq was in terahertz or...? or the form of the device was the solid state version Woodward favors?
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/07/2014 05:52 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240517#msg1240517">Quote from: aero on 08/07/2014 04:20 AM</a>
Getting back to EM Drive, am I correct in thinking that the higher the frequency the more power consumed and the smaller the RF resonator?

I'm trying to guess how large a mature EM Drive might be physically? (Assuming that it does mature.) I'm pretty sure that the power sources would be a lot bigger than the EM Drive itself.

From what I've read it doesn't look like there is any reason to hang the drives off the tail end of the spaceship, rather just set them in the electronics bay, or maybe in the Captain's cabin. Of course they would need to be attached to a thrust structure. If you wanted redundancy you could just weld 20 or so of the 5% sized EM Drives on the stern of your spaceship.

I'm hoping that by the end of the year we can start speculating configurations in earnest.
I like this. Do we need to wait until further confirmation to speculate on spacecraft configs?
We all know that the propellant-less thrust effect may be false, but shirley it is worth exploring.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/07/2014 05:55 AM
I favor in between the outer hull and the pressure vessel wall with various orientations to provide agility.

EDIT:  maybe a couple of panels of them or maybe 4 panels mounted on gimbals to change the orientation through a spherical 360 degrees.
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/07/2014 06:00 AM
I think a puller config would be best. So mount these things at the prow. Yes?
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/07/2014 06:04 AM
they really could go anywhere if they were attached to some significant structure of the ship like a keel or the 'tween hulls. so up front should work. but why not go for a configuration that negates the need for a separate set of maneuver engines thrusters? make them mobile or have some for each axis.
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/07/2014 06:10 AM
i guess if you had them inside the pressure hull you could maintain or replace modules while in a shirt sleeve environment.  your engineers would thank you.
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/07/2014 06:33 AM
I guess you would have separate cavities for each axis. You would need them fore and aft for rotation.
They all would have to be superconducting. I think that would be best done outside the pressure hull. Not sure.
Title: Re: EM Drive Developments
Post by: aero on 08/07/2014 07:25 AM
Why would they need to be superconducting, the test articles weren't?

And I wonder if somehow some RF electronics wizard could manage to change thrust direction electronically. Doesn't matter to much, these things are small and low mass. But before I can decide whether to mount them inside or outside the pressure hull, I'd like to know for sure that the hull doesn't interfere with the drive and that the drive isn't a safety hazard for the crew. If that's all OK I might mount the control thrusters inside the pressure hull in cabinets near the same relative locations where we currently mount them.

As for the main drives, I think I would distribute them throughout the ship to reduce the need for massive force transfer structures from the engines to the rest of the ship structure. I might even double them up with each pair having a forward and a reverse thruster. Heck, I might even do away with the bow and stern idea, and build a double ender, with a bow on both ends. That way there would be no need for a turn over maneuver, just put it in reverse. Of course the thrusters could be swiveled, instead. There are no rigid fuel lines, just a flexible microwave cable. Need to look at reliability to decide.
Title: Re: EM Drive Developments
Post by: aero on 08/07/2014 07:35 AM
I did some thrust calculations for the truncated cone EM Drive using F = .0912 mN at 17 W input power. I then ranged jet energy from 10 to 17 watts.

Calculated Isp ranges from 22,400 s (10 W) to 38,000 s (17 W)
Calculated mdot, ranges from 4.16E-10 kg/s (10 W) to 2.45E-10 kg/s (17 W).
That is a nice range to be in.

If I assume the power electronics are 60% efficient, jet energy is 10.2 W, so Isp = 22,800 seconds and mdot = 4.08E-10 kg/s.

Now all that is needed is a theroy of where that mdot comes from and where it goes to! It does occur to me that if we knew the amount of waste heat coming off the EM Drive we could estimate the jet energy from the experiment using total energy = jet energy + waste energy.
------------------
1) Thrust, F = mdot * Ve, and
2) jet energy, E = 0.5 mdot * Ve^2
 substituting 1) into 2) clears mdot and gives
E = 0.5 F * Ve so Ve = 2* E /F . Now calculate mdot from 1).
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/07/2014 08:26 AM
well i don't know about shayer's...but is the thermal trace that woodward graphs the waste heat?
Title: Re: EM Drive Developments
Post by: Star One on 08/07/2014 03:58 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240433#msg1240433">Quote from: bubbagret on 08/06/2014 10:55 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240430#msg1240430">Quote from: Star One on 08/06/2014 10:51 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240425#msg1240425">Quote from: IslandPlaya on 08/06/2014 10:46 PM</a>
For what it's worth I speed-read a lot of things and I'm good at it.
I am still going over the NASA paper properly.
So far I think that they have been very careful about outside influences.
Ion wind, heat based stuff not so much... I will continue pouring over it.

How about testing in hard vacuum with a Tesla cage around it?

You mean Faraday cage supposedly...

Yes I don't know why I said Tesla.

The reason I mentioned those two is I saw a number of online commentators claiming these are the sort of tests it needed to be subjected too.

Far be it for me too suggest they were setting deliberately high hurdles.

Title: Re: EM Drive Developments
Post by: aero on 08/07/2014 06:33 PM
Here is an article with a more accepting slant. Still has errors but what can you do. The tests were NOT performed in vacuum.

http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive (http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive)

Title: Re: EM Drive Developments
Post by: Star One on 08/07/2014 07:01 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240753#msg1240753">Quote from: aero on 08/07/2014 06:33 PM</a>
Here is an article with a more accepting slant. Still has errors but what can you do. The tests were NOT performed in vacuum.

http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive (http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive)

It does make one very important point that is there is no agreed theory on how high temperature superconductors work but because they have been replicated so many times we know they do.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/07/2014 08:13 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240771#msg1240771">Quote from: Star One on 08/07/2014 07:01 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240753#msg1240753">Quote from: aero on 08/07/2014 06:33 PM</a>
Here is an article with a more accepting slant. Still has errors but what can you do. The tests were NOT performed in vacuum.

http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive (http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive)

It does make one very important point that is there is no agreed theory on how high temperature superconductors work but because they have been replicated so many times we know they do.
There has actually been a paper on high-temp superconductors published recently, explaining how they work. It is supported by computer codes to simulate them as well. Sorry can't find the link at the mo.

Title: Re: EM Drive Developments
Post by: aero on 08/07/2014 08:28 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240813#msg1240813">Quote from: IslandPlaya on 08/07/2014 08:13 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240771#msg1240771">Quote from: Star One on 08/07/2014 07:01 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240753#msg1240753">Quote from: aero on 08/07/2014 06:33 PM</a>
Here is an article with a more accepting slant. Still has errors but what can you do. The tests were NOT performed in vacuum.

http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive (http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive)

It does make one very important point that is there is no agreed theory on how high temperature superconductors work but because they have been replicated so many times we know they do.
There has actually been a paper on high-temp superconductors published recently, explaining how they work. It is supported by computer codes to simulate them as well. Sorry can't find the link at the mo.

Doesn't matter. They worked for a long time before anyone figured out how. EM Drive, if verified to work, is in that stage before anyone has figured how.

Title: Re: EM Drive Developments
Post by: aero on 08/08/2014 12:14 AM
Does anyone know if the classic EM Drive has ever been operated with a strain gauge attached to the end plates? That should be an easy way to prove or disprove the pressure idea of operation of the device.
Title: Re: EM Drive Developments
Post by: sanman on 08/08/2014 02:30 AM
I, for one, am glad if the NASA team's test results announcement has created a flutter. At least this will encourage more experts to get involved in coming up with either a definitive proof or disproof on this matter. At least one way or the other, the matter can then be settled.
Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/08/2014 07:04 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240822#msg1240822">Quote from: aero on 08/07/2014 08:28 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240813#msg1240813">Quote from: IslandPlaya on 08/07/2014 08:13 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240771#msg1240771">Quote from: Star One on 08/07/2014 07:01 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240753#msg1240753">Quote from: aero on 08/07/2014 06:33 PM</a>
Here is an article with a more accepting slant. Still has errors but what can you do. The tests were NOT performed in vacuum.

http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive (http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive)

It does make one very important point that is there is no agreed theory on how high temperature superconductors work but because they have been replicated so many times we know they do.
There has actually been a paper on high-temp superconductors published recently, explaining how they work. It is supported by computer codes to simulate them as well. Sorry can't find the link at the mo.

Doesn't matter. They worked for a long time before anyone figured out how. EM Drive, if verified to work, is in that stage before anyone has figured how.

They're not comparable because superconductivity never violated any fundamental laws of physics.  The claims about the EmDrive violate fundamental laws of physics.

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/08/2014 07:07 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240927#msg1240927">Quote from: sanman on 08/08/2014 02:30 AM</a>
I, for one, am glad if the NASA team's test results announcement has created a flutter. At least this will encourage more experts to get involved in coming up with either a definitive proof or disproof on this matter. At least one way or the other, the matter can then be settled.

It's already considered settled by mainstream science: there is nothing there.  Mainstream scientists have already looked into the EmDrive years ago and convinced themselves it doesn't work.  That didn't do a thing to discourage its proponents.

Nothing is going to change.  I'll bet you in five years the current state will be exactly what it is today: mainstream science remains convinced there's no effect there, and believers will still insist the effect is real.

Title: Re: EM Drive Developments
Post by: QuantumG on 08/08/2014 07:50 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240958#msg1240958">Quote from: ChrisWilson68 on 08/08/2014 07:07 AM</a>
It's already considered settled by mainstream science: there is nothing there.  Mainstream scientists have already looked into the EmDrive years ago and convinced themselves it doesn't work.  That didn't do a thing to discourage its proponents.

There's no such thing as "mainstream science".

There's stuff that works and stuff that doesn't. The EMDrive is firmly in the latter category. The day it makes it into the former will be called a "breakthrough".

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/08/2014 08:32 AM
here is a slide that kind of shows the set up it's not as good as the video i am looking for but you can see some of the items i mentioned like the contacts the faraday cage the vacuum level and so forth in slide 4:

http://nextbigfuture.com/2010/02/mach-effect-propulsion-research-update.html

Title: Re: EM Drive Developments
Post by: sanman on 08/08/2014 02:04 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240957#msg1240957">Quote from: ChrisWilson68 on 08/08/2014 07:04 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240822#msg1240822">Quote from: aero on 08/07/2014 08:28 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240813#msg1240813">Quote from: IslandPlaya on 08/07/2014 08:13 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240771#msg1240771">Quote from: Star One on 08/07/2014 07:01 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240753#msg1240753">Quote from: aero on 08/07/2014 06:33 PM</a>
Here is an article with a more accepting slant. Still has errors but what can you do. The tests were NOT performed in vacuum.

http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive (http://www.wired.co.uk/news/archive/2014-08/07/10-qs-about-nasa-impossible-drive)

It does make one very important point that is there is no agreed theory on how high temperature superconductors work but because they have been replicated so many times we know they do.
There has actually been a paper on high-temp superconductors published recently, explaining how they work. It is supported by computer codes to simulate them as well. Sorry can't find the link at the mo.

Doesn't matter. They worked for a long time before anyone figured out how. EM Drive, if verified to work, is in that stage before anyone has figured how.

They're not comparable because superconductivity never violated any fundamental laws of physics.  The claims about the EmDrive violate fundamental laws of physics.

I dunno - before people started thinking of Cooper's pairs, it seemed like Superconductivity apparently  violated the need for Work to be done.

Title: Re: EM Drive Developments
Post by: sanman on 08/08/2014 02:06 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240965#msg1240965">Quote from: QuantumG on 08/08/2014 07:50 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240958#msg1240958">Quote from: ChrisWilson68 on 08/08/2014 07:07 AM</a>
It's already considered settled by mainstream science: there is nothing there.  Mainstream scientists have already looked into the EmDrive years ago and convinced themselves it doesn't work.  That didn't do a thing to discourage its proponents.

There's no such thing as "mainstream science".

There's stuff that works and stuff that doesn't. The EMDrive is firmly in the latter category. The day it makes it into the former will be called a "breakthrough".

When you're talking about micro-Newtons, it's hard to clearly see what's working or isn't. More experiments can be done to clarify if that thrust is happening or isn't.

Why did they experience the thrust in the opposite direction when they reversed the orientation of the device?

Title: Re: EM Drive Developments
Post by: Star One on 08/08/2014 04:03 PM
This story certainly has spread far and wide it's even appeared in entertainment website forums.

I hope this doesn't cause any kind of backlash in the reputation of NASA if this all proves to be nothing, I know NASA isn't a homogenous whole, we know that but does the public which tends to just see the initials.
Title: Re: EM Drive Developments
Post by: cuddihy on 08/08/2014 04:15 PM
I'm interested by the Paul March speculation about electrostriction of the resonant cavity combined with dieletric causing possible Mach Effect that would explain the thrust without the conservation of mass issues EM drives represent. (Because mass used is external to the device, see the Woodward Effect thread).
Title: Re: EM Drive Developments
Post by: aero on 08/08/2014 04:35 PM

Quote
Why did they experience the thrust in the opposite direction when they reversed the orientation of the device?

I think they measured thrust relative to their measurement device. When they turned the EM thruster 180 degrees relative to their measurement device, it thrusted in the same direction relative to the thruster, but in the reverse direction relative to their measurement device.

Title: Re: EM Drive Developments
Post by: DMeader on 08/08/2014 04:45 PM
I present the following. No personal flames please.
https://medium.com/starts-with-a-bang/how-to-fool-the-world-with-bad-science-7a9318dd1ae6 (https://medium.com/starts-with-a-bang/how-to-fool-the-world-with-bad-science-7a9318dd1ae6)

Title: Re: EM Drive Developments
Post by: Star One on 08/08/2014 05:05 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241094#msg1241094">Quote from: DMeader on 08/08/2014 04:45 PM</a>
I present the following. No personal flames please.
https://medium.com/starts-with-a-bang/how-to-fool-the-world-with-bad-science-7a9318dd1ae6 (https://medium.com/starts-with-a-bang/how-to-fool-the-world-with-bad-science-7a9318dd1ae6)

Yet another article where it appears that the author does not seem to have read the full report, notice the mention of the null device issue.

Title: Re: EM Drive Developments
Post by: DMeader on 08/08/2014 05:08 PM
Maybe "these article writers" know bad science when they see it.
Title: Re: EM Drive Developments
Post by: Star One on 08/08/2014 05:13 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241111#msg1241111">Quote from: DMeader on 08/08/2014 05:08 PM</a>
Maybe "these article writers" know bad science when they see it.

Do we know whether the author read the full report rather than the abstract that was initially released?

Title: Re: EM Drive Developments
Post by: aero on 08/08/2014 06:48 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241113#msg1241113">Quote from: Star One on 08/08/2014 05:13 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241111#msg1241111">Quote from: DMeader on 08/08/2014 05:08 PM</a>
Maybe "these article writers" know bad science when they see it.

Do we know whether the author read the full report rather than the abstract that was initially released?

We don't know if he read the full report but we do know that he is quoting from the abstract because he says so.
He also reports the sensitivity of the measurement device to be an order of magnitude worse than all other claims I have seen.

Quote
•The “test” performed at NASA was sensitive to a minimum thrust threshold of about 10-to-15 microNewtons, and the “positive result” claimed detection of somewhere between 30-to-50 microNewtons of thrust.

Title: Re: EM Drive Developments
Post by: Star One on 08/08/2014 07:04 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241142#msg1241142">Quote from: aero on 08/08/2014 06:48 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241113#msg1241113">Quote from: Star One on 08/08/2014 05:13 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241111#msg1241111">Quote from: DMeader on 08/08/2014 05:08 PM</a>
Maybe "these article writers" know bad science when they see it.

Do we know whether the author read the full report rather than the abstract that was initially released?

We don't know if he read the full report but we do know that he is quoting from the abstract because he says so.
He also reports the sensitivity of the measurement device to be an order of magnitude worse than all other claims I have seen.

Quote
•The “test” performed at NASA was sensitive to a minimum thrust threshold of about 10-to-15 microNewtons, and the “positive result” claimed detection of somewhere between 30-to-50 microNewtons of thrust.

Thanks I missed that part but deduced from the rest of the article that it was probably from the abstract.

Title: Re: EM Drive Developments
Post by: GregA on 08/08/2014 11:22 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241094#msg1241094">Quote from: DMeader on 08/08/2014 04:45 PM</a>
I present the following. No personal flames please.
https://medium.com/starts-with-a-bang/how-to-fool-the-world-with-bad-science-7a9318dd1ae6 (https://medium.com/starts-with-a-bang/how-to-fool-the-world-with-bad-science-7a9318dd1ae6)
The analogy drawn would infer that top scientists have tried to replicate the effect and failed. If that was true I'd side far more with the skeptics.

As it is I believe it needs such research, no?

(Edit: It would be bad science to not do it)

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/08/2014 11:35 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241212#msg1241212">Quote from: GregA on 08/08/2014 11:22 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241094#msg1241094">Quote from: DMeader on 08/08/2014 04:45 PM</a>
I present the following. No personal flames please.
https://medium.com/starts-with-a-bang/how-to-fool-the-world-with-bad-science-7a9318dd1ae6 (https://medium.com/starts-with-a-bang/how-to-fool-the-world-with-bad-science-7a9318dd1ae6)
The analogy drawn would infer that top scientists have tried to replicate the effect and failed. If that was true I'd side far more with the skeptics.

As it is I believe it needs such research, no?

(Edit: It would be bad science to not do it)
Fie! The high Priests of the great infernal entity known as Science have powers to discern anything heretical (in violation of the laws of physics) without even knowing what it's about or if it really does violate the laws of physics because anything weird has to violate the law; it just does . din'tcha know that? Infidel!

Title: Re: EM Drive Developments
Post by: Lars_J on 08/09/2014 05:42 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241214#msg1241214">Quote from: Stormbringer on 08/08/2014 11:35 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241212#msg1241212">Quote from: GregA on 08/08/2014 11:22 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241094#msg1241094">Quote from: DMeader on 08/08/2014 04:45 PM</a>
I present the following. No personal flames please.
https://medium.com/starts-with-a-bang/how-to-fool-the-world-with-bad-science-7a9318dd1ae6 (https://medium.com/starts-with-a-bang/how-to-fool-the-world-with-bad-science-7a9318dd1ae6)
The analogy drawn would infer that top scientists have tried to replicate the effect and failed. If that was true I'd side far more with the skeptics.

As it is I believe it needs such research, no?

(Edit: It would be bad science to not do it)
Fie! The high Priests of the great infernal entity known as Science have powers to discern anything heretical (in violation of the laws of physics) without even knowing what it's about or if it really does violate the laws of physics because anything weird has to violate the law; it just does . din'tcha know that? Infidel!

...as opposed to the true propulsion breakthrough - wishful thinking?

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/09/2014 06:13 AM
i have seen people here pan fusion propulsion.; a likely near term advancement. i have seem them pan VASIMR and other advanced concepts that aren't that unlikely. i have even seen them argue about this or that chemical propulsion scheme being unrealistic or undesireable. so exactly what advanced concepts are non "woo woo?" to everyone's satisfaction? hamster flatulence? what?
Title: Re: EM Drive Developments
Post by: QuantumG on 08/09/2014 06:24 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241310#msg1241310">Quote from: Stormbringer on 08/09/2014 06:13 AM</a>
i have seen people here pan fusion propulsion.; a likely near term advancement. i have seem them pan VASIMR and other advanced concepts that aren't that unlikely. i have even seen them argue about this or that chemical propulsion scheme being unrealistic or undesireable. so exactly what advanced concepts are non "woo woo?" to everyone's satisfaction? hamster flatulence? what?

Seems to me that everyone wants to talk about the stuff that has no hope of working and no-one ever wants to talk about the stuff that could be made to work with enough money. People used to love talking about solar sails, but now that one has flown (IKAROS) and two more are under development (Sunjammer and LightSail) suddenly no-one is interested anymore. Similarly, few people are terribly interested in talking about nuclear thermal rockets unless they're some impractical fusion contraption, but they were all the rage back in Heinlein's day. Reality has the nasty habit of boring the dreamers.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/09/2014 06:49 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241312#msg1241312">Quote from: QuantumG on 08/09/2014 06:24 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241310#msg1241310">Quote from: Stormbringer on 08/09/2014 06:13 AM</a>
i have seen people here pan fusion propulsion.; a likely near term advancement. i have seem them pan VASIMR and other advanced concepts that aren't that unlikely. i have even seen them argue about this or that chemical propulsion scheme being unrealistic or undesireable. so exactly what advanced concepts are non "woo woo?" to everyone's satisfaction? hamster flatulence? what?

Seems to me that everyone wants to talk about the stuff that has no hope of working and no-one ever wants to talk about the stuff that could be made to work with enough money. People used to love talking about solar sails, but now that one has flown (IKAROS) and two more are under development (Sunjammer and LightSail) suddenly no-one is interested anymore. Similarly, few people are terribly interested in talking about nuclear thermal rockets unless they're some impractical fusion contraption, but they were all the rage back in Heinlein's day. Reality has the nasty habit of boring the dreamers.
oh there are plenty of threads about all of those things and countless ones discussing this or that chemical scheme. but the ones that break new ground get a lot of grief. while in my opinion there is no purely chemical scheme that should be classified as advanced. solar sails sure. even though there are a lot of issues that are not easy to fix. plasma sails; ok I'll buy it; but they are leaky. NTRs? sure; but do it already. damn it we have had the knowledge from the 1960s. do it already or shaddap. Fusion? ok. there are some things that may be as few as 5 years off there. This other (what they think of as woo woo or oogly moogly) stuff? low probability of success but huge payoff upon success for not much effort or money. worth discussing. worth low level funding at least. It's not like it hurts funding for other projects. NASA won't launch one less probe because they gave Dr White some modest resources. Not one Orion was hurt in the making of his coil thingy.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/09/2014 06:57 AM
Dr White may have in fact gotten his funding by couch fishing in the employee break room chair cushions for all i know. It'd probably cover it.
Title: Re: EM Drive Developments
Post by: Star One on 08/09/2014 09:30 AM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241312#msg1241312">Quote from: QuantumG on 08/09/2014 06:24 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241310#msg1241310">Quote from: Stormbringer on 08/09/2014 06:13 AM</a>
i have seen people here pan fusion propulsion.; a likely near term advancement. i have seem them pan VASIMR and other advanced concepts that aren't that unlikely. i have even seen them argue about this or that chemical propulsion scheme being unrealistic or undesireable. so exactly what advanced concepts are non "woo woo?" to everyone's satisfaction? hamster flatulence? what?

Seems to me that everyone wants to talk about the stuff that has no hope of working and no-one ever wants to talk about the stuff that could be made to work with enough money. People used to love talking about solar sails, but now that one has flown (IKAROS) and two more are under development (Sunjammer and LightSail) suddenly no-one is interested anymore. Similarly, few people are terribly interested in talking about nuclear thermal rockets unless they're some impractical fusion contraption, but they were all the rage back in Heinlein's day. Reality has the nasty habit of boring the dreamers.

I think with solar sails it's more their slow pace of development, I am sure we were talking about these back in the eighties but they are still in the early stages of use. Unfortunately the internet seems easily bored with little patience for such projects.

Title: Re: EM Drive Developments
Post by: sanman on 08/09/2014 12:47 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241312#msg1241312">Quote from: QuantumG on 08/09/2014 06:24 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241310#msg1241310">Quote from: Stormbringer on 08/09/2014 06:13 AM</a>
i have seen people here pan fusion propulsion.; a likely near term advancement. i have seem them pan VASIMR and other advanced concepts that aren't that unlikely. i have even seen them argue about this or that chemical propulsion scheme being unrealistic or undesireable. so exactly what advanced concepts are non "woo woo?" to everyone's satisfaction? hamster flatulence? what?

Seems to me that everyone wants to talk about the stuff that has no hope of working and no-one ever wants to talk about the stuff that could be made to work with enough money. People used to love talking about solar sails, but now that one has flown (IKAROS) and two more are under development (Sunjammer and LightSail) suddenly no-one is interested anymore. Similarly, few people are terribly interested in talking about nuclear thermal rockets unless they're some impractical fusion contraption, but they were all the rage back in Heinlein's day. Reality has the nasty habit of boring the dreamers.

Even if it seems flimsy, people naturally want to look for some new possibility that can bypass some of the existing strictures that limit spaceflight. "But physics can't be bypassed," you say - well who can claim omniscient knowledge of physics? There may be small exploit opportunities which can be exposed here and there. The fact is that the Quantum Vacuum exists, and it interacts with everything in our world - without violating Conservation of Momentum. Maybe there's a way to push off it without expelling propellant, and maybe this device is demonstrating such an effect. It seems relatively straightforward to attempt a more thorough investigation to provide either proof or disproof that some kind of propulsive effect is happening.

Title: Re: EM Drive Developments
Post by: SteveKelsey on 08/09/2014 04:02 PM
Classical physics ( Newton plus Maxwell) thought it had the universe sewn up and all that was left was details and taxonomy. The view at the time was that it could explain everything, except for one little problem called black body radiation.
Through this small chink in the armour we got quantum mechanics, QED, and eventually the Standard Model. At the time, quantum mechanics was reviled by mainstream authocrats. QM seemed bizarre and irrelevant but something had to explain the odd and ' unscientific' results.

The  Standard Model is hugely successful, and full of holes. http://www.math.columbia.edu/~woit/wordpress/?p=5946&cpage=1
There is no single standard model. The current orthodoxy did not predict and currently cannot explain neutrino mass, entanglement, dark matter, dark energy,accelerated  inflation, the 'cold dark spot' the 'axis of evil'.
How many chinks in the armour of your orthodoxy do you need?
When  the fifty or so 'free parameters' and the need for normalisation have been removed then it might be possible to claim we understand everything. Until that point, experiment carefully and be prepared for surprises.
Title: Re: EM Drive Developments
Post by: frobnicat on 08/09/2014 07:13 PM
It's not that we know everything, but at some energy densities/scales the amount experience confirming the "laws" is so huge than when an experiments claims to see a phenomenon that is in apparent contradiction to those laws without resorting to high energy physics or cosmological scales then it is a sure bet to discard the said experiment at a glance of the summary : the explanation to make said anomaly real and yet compatible with already known results seems far too contrived and unnatural. For instance if someone claims that a fancy shape has slightly more buoyancy than the weight of fluid displaced by such shape, because of the shape, you would surely dismiss the claim without looking the details of the shape and measuring apparatus : Archimedes principle holds and will continue to hold whenever a macroscopic shape is immersed and stand still in a fluid, no matter how old beard physics or how fancy the shape. The good old principles are only broken when going beyond some scope of validity, say newtonian additivity of speed is broken, but only when approaching c, mass conservation is broken but only when taping into nuclear energy levels, the sum of the angles of a triangle is not 180° but only near very heavy compact objects, mass_energy conservation is apparently broken but only on cosmological space-time scales...
So yes we had quite a number of surprises last century or so but the absolute principles of 19th century and before stayed good principles, even as approximations, in their range of validity. What does the EMdrive to reach beyond the range of validity so well established for conservation of energy ? Pushing on vacuum virtual particles sounds nice but vacuum is lorentz invariant so far (it's not like possible violations have not been investigated : http://en.wikipedia.org/wiki/Modern_searches_for_Lorentz_violation (http://en.wikipedia.org/wiki/Modern_searches_for_Lorentz_violation)) and pushing on a lorentz invariant "medium" is not only cheap momentum but basically "free energy", so you cannot claim that without claiming free energy, or some form of transfer of energy from vacuum zero point to the device, that would imply negative energy radiating (contrary to a static casimir effect gap), probably FTL I can't tell, but the point is the whole contemporary physics edifice is crumbling, you can't just borrow a little bit of cheap lorentz invariant momentum and keep the rest untouched.
The whole contemporary physics edifice will probably be extended/replaced some times ahead (and shown to be an approximation or limit to more general principles) but has shown enough validity in a wide range of scales/densities that a device that appear to be well within those ranges be met with utter skepticism by the tenants of the orthodoxy who have a view of the amazing consistency of the whole so far, even if "full of holes". This should be no surprise, this is not a scandal. If the thrust depended clearly on its orientation relative to the stars (aether wind) I guess this would be met with more curiosity as it could relieve the "free energy" aspect.
That said, while I would put my bet with the skeptics, well, you never know, I think this experience's results is worth elucidation, a week clearly is not enough for a small team to check a number of parameters against the values : what if in vacuum, what if changing place of device relative to chamber walls, what if adding another strong magnet somewhere else to the damping one, hell, what if halving the power, we don't even know if the effect would be linear ... would need hundreds measuring sessions. If only for advancing the know how of reliably measuring orthodox low or null thrusts when RF resonant cavities are involved somehow is worth more.
Title: Re: EM Drive Developments
Post by: sanman on 08/09/2014 07:26 PM
For the sake of argument, if the entire electrical input to the test apparatus had been converted into photons, then could the resulting photon rocket have generated comparable levels of force as what was observed?
Title: Re: EM Drive Developments
Post by: CW on 08/09/2014 07:42 PM
I think one has to be careful when calling found physical principles 'laws'. They are not laws in the absolute sense, as in given by 'God', or being the final answer. The only thing we can say about the principles that we found and verified by peer-reviewed experiments up to any given point in time is: To the best of our current knowledge, this is what happens. A very important point to make.

When an experiment seems to 'violate' known physical 'laws', then one could also say instead: That experiment seems to demonstrate a behavior that, to the best of our current knowledge, should not occur. You see the difference that the wording makes? The first paraphrase pretends to be a prosecutor in court, immediately declaring anyone who goes against "that what we know so far" a criminal who 'violates' a 'law'. It is a funny position, because this is what it really says: Something was measured, that seems to go against that which we know to be 'true' - and since it is like that, it must be wrong. This is not how science works. For that to decide, there is peer-review.

I acknowledge that too many revolutionary inventions were claimed, in the biggest part by self-deluded individuals and oftentimes outright frauds. But when science becomes dogma, you can stop your work and go pray in a church. It would be time better spent.

Best regards
Title: Re: EM Drive Developments
Post by: CW on 08/09/2014 07:46 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241469#msg1241469">Quote from: sanman on 08/09/2014 07:26 PM</a>
For the sake of argument, if the entire electrical input to the test apparatus had been converted into photons, then could the resulting photon rocket have generated comparable levels of force as what was observed?

That is an excellent question. I think that the difference lies in the fact that in a photon rocket, each photon that imparts impulse to the rocket, only gets reflected exactly one time. In a superconducting high-Q resonant cavity, the photons get reflected e.g. a billion times until they get lost. So, my best guess is: No, the levels of force should not be comparable at all, since the photons can impart an impulse to a compact cavity many millions or even billions of times per second. Quite a hefty multiplier.

Title: Re: EM Drive Developments
Post by: sanman on 08/09/2014 07:53 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241478#msg1241478">Quote from: CW on 08/09/2014 07:46 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241469#msg1241469">Quote from: sanman on 08/09/2014 07:26 PM</a>
For the sake of argument, if the entire electrical input to the test apparatus had been converted into photons, then could the resulting photon rocket have generated comparable levels of force as what was observed?

That is an excellent question. I think that the difference lies in the fact that in a photon rocket, each photon that imparts impulse to the rocket, only gets reflected exactly one time. In a superconducting high-Q resonant cavity, the photons get reflected e.g. a billion times until they get lost. So, my best guess is: No, the levels of force should not be comparable at all, since the photons can impart an impulse to a compact cavity many millions or even billions of times per second. Quite a hefty multiplier.

That's what I figured the response would be - but doesn't Conservation of Momentum apply to a resonant cavity, no matter how many times photons bounce back and forth inside it? If those were pingpong balls bouncing back-and-forth inside a cavity, we'd say there was no net momentum imparted to the apparatus from all their bouncing, because of Conservation of Momentum.

So if the force level observed is greater than what a photon rocket would hypothetically create, then doesn't that imply that there's more going on here than what traditional physics would suggest? (eg. Q-thruster, some interaction with Quantum Vacuum, etc)

Title: Re: EM Drive Developments
Post by: aero on 08/09/2014 08:15 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241478#msg1241478">Quote from: CW on 08/09/2014 07:46 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241469#msg1241469">Quote from: sanman on 08/09/2014 07:26 PM</a>
For the sake of argument, if the entire electrical input to the test apparatus had been converted into photons, then could the resulting photon rocket have generated comparable levels of force as what was observed?

That is an excellent question. I think that the difference lies in the fact that in a photon rocket, each photon that imparts impulse to the rocket, only gets reflected exactly one time. In a superconducting high-Q resonant cavity, the photons get reflected e.g. a billion times until they get lost. So, my best guess is: No, the levels of force should not be comparable at all.

No. I already did that calculation. The problem with that is the jet energy which would result. If the force, F = mdot * Ve were caused by photons moving at the speed of light, then mdot = 3.04E-13 kg/s and the jet energy, E= mdot * Ve^2/2 = .5*F*Ve . That gives E =  13,670.54 J/s or watts for a drive power of 17 watts. So conservation of energy is violated.

I have imagined a different failure mode. I hope i'ts wrong because I really want the EM thruster to be real, and I wonder how an outfit with "Aeronautics" in its name could make such a mistake, but consider this.

The EM thruster has never been tested in vacuum, and they all have been leaky, that is, total air pressure inside and outside is equal and equals atmospheric. Imagine then that some mechanism sets up an air circulation within the EM thruster. Circulating air moves with some velocity V across the inside of the large end of the thruster, recirculating around the open cavity past the small end. Air pressure outside the large end = Pt, total pressure but static air pressure inside the large end, Ps = Pt -q and q = 0.5* rho*V^2.

I ran the numbers assuming 140 mm diameter, uniform velocity and sea level air density. The force of air pressure equals the thrust force claimed when V = ~0.1 m/s. The actual number Excel calculated was 95.74677721 mm/s.

I hope you can gently shoot down this idea.

Title: Re: EM Drive Developments
Post by: CW on 08/09/2014 08:19 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241481#msg1241481">Quote from: sanman on 08/09/2014 07:53 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241478#msg1241478">Quote from: CW on 08/09/2014 07:46 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241469#msg1241469">Quote from: sanman on 08/09/2014 07:26 PM</a>
For the sake of argument, if the entire electrical input to the test apparatus had been converted into photons, then could the resulting photon rocket have generated comparable levels of force as what was observed?

That is an excellent question. I think that the difference lies in the fact that in a photon rocket, each photon that imparts impulse to the rocket, only gets reflected exactly one time. In a superconducting high-Q resonant cavity, the photons get reflected e.g. a billion times until they get lost. So, my best guess is: No, the levels of force should not be comparable at all, since the photons can impart an impulse to a compact cavity many millions or even billions of times per second. Quite a hefty multiplier.

That's what I figured the response would be - but doesn't Conservation of Momentum apply to a resonant cavity, no matter how many times photons bounce back and forth inside it? If those were pingpong balls bouncing back-and-forth inside a cavity, we'd say there was no net momentum imparted to the apparatus from all their bouncing, because of Conservation of Momentum.

So if the force level observed is greater than what a photon rocket would hypothetically create, then doesn't that imply that there's more going on here than what traditional physics would suggest? (eg. Q-thruster, some interaction with Quantum Vacuum, etc)

All that we can IMHO say so far is, that if the measurements are confirmed under better controlled conditions as well, that by some hitherto unknown physical interaction an imbalance in momentum transfer is produced and that the photons, which are reflected N times in this resonant cavity on the desired surface, get N times the opportunity to do a momentum transfer. If this really works, then it would make sense that, as Shawyer claims, such a drive would be the perfect means to produce a static force that counteracts the gravitational force of any kind of airborne objects.

There is one thing I find a bit curious. Momentum is defined as p = m*v . Now, if the drive were just to produce a force to counteract Earth's gravity, in how far is impulse conservation not adhered to? Above formula states clearly, that you need to have some relative speed going on for any kind of measurable momentum. No movement - no impulse. I mean, it is IMHO comparable to a book standing on a table. No-one would imply that the book were to 'violate' impulse conservation in any way ;) . So, what's going on here?

Regards

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/09/2014 08:42 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241487#msg1241487">Quote from: aero on 08/09/2014 08:15 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241478#msg1241478">Quote from: CW on 08/09/2014 07:46 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241469#msg1241469">Quote from: sanman on 08/09/2014 07:26 PM</a>
For the sake of argument, if the entire electrical input to the test apparatus had been converted into photons, then could the resulting photon rocket have generated comparable levels of force as what was observed?

That is an excellent question. I think that the difference lies in the fact that in a photon rocket, each photon that imparts impulse to the rocket, only gets reflected exactly one time. In a superconducting high-Q resonant cavity, the photons get reflected e.g. a billion times until they get lost. So, my best guess is: No, the levels of force should not be comparable at all.

No. I already did that calculation. The problem with that is the jet energy which would result. If the force, F = mdot * Ve were caused by photons moving at the speed of light, then mdot = 3.04E-13 kg/s and the jet energy, E= mdot * Ve^2/2 = .5*F*Ve . That gives E =  13,670.54 J/s or watts for a drive power of 17 watts. So conservation of energy is violated.

I have imagined a different failure mode. I hope i'ts wrong because I really want the EM thruster to be real, and I wonder how an outfit with "Aeronautics" in its name could make such a mistake, but consider this.

The EM thruster has never been tested in vacuum, and they all have been leaky, that is, total air pressure inside and outside is equal and equals atmospheric. Imagine then that some mechanism sets up an air circulation within the EM thruster. Circulating air moves with some velocity V across the inside of the large end of the thruster, recirculating around the open cavity past the small end. Air pressure outside the large end = Pt, total pressure but static air pressure inside the large end, Ps = Pt -q and q = 0.5* rho*V^2.

I ran the numbers assuming 140 mm diameter, uniform velocity and sea level air density. The force of air pressure equals the thrust force claimed when V = ~0.1 m/s. The actual number Excel calculated was 95.74677721 mm/s.

I hope you can gently shoot down this idea.
i dunno if this EM thruster has been tested in vacuum or not but I know that Dr Woodward's version of this thing has been tested in vacuum.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/09/2014 08:45 PM
Dr Woodward's slide shows a vacuum strength of 5.0 milli Tor.
Title: Re: EM Drive Developments
Post by: Hanelyp on 08/09/2014 08:52 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241481#msg1241481">Quote from: sanman on 08/09/2014 07:53 PM</a>
That's what I figured the response would be - but doesn't Conservation of Momentum apply to a resonant cavity, no matter how many times photons bounce back and forth inside it? If those were pingpong balls bouncing back-and-forth inside a cavity, we'd say there was no net momentum imparted to the apparatus from all their bouncing, because of Conservation of Momentum.

So if the force level observed is greater than what a photon rocket would hypothetically create, then doesn't that imply that there's more going on here than what traditional physics would suggest? (eg. Q-thruster, some interaction with Quantum Vacuum, etc)
The forces inside a resonant chamber should be balanced, except for the feed point.  The transmission cable connecting the resonant chamber to the microwave generator is carrying momentum along with the energy.  If there's a poor match between feed line and resonator, photons bouncing back and forth may carry momentum far in excess of a single transfer of the energy.  This can be a problem for experimental integrity if the microwave generator is not on the force balance.

Title: Re: EM Drive Developments
Post by: aero on 08/10/2014 03:49 AM
Back on the previous page, I pose a situation where air circulation inside the thruster caused the pressure difference measured as thrust. http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241487#msg1241487 (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241487#msg1241487)

It occurs to me that this idea does not hold water because it was reported that with the dielectric RF resonator removed, the measurement was zero to the system precision. If air circulates with the resonator installed, then it should also circulate (to some extent) with the resonator removed, shouldn't it?
Title: Re: EM Drive Developments
Post by: GregA on 08/10/2014 05:20 AM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241499#msg1241499">Quote from: Hanelyp on 08/09/2014 08:52 PM</a>
The forces inside a resonant chamber should be balanced, except for the feed point.  The transmission cable connecting the resonant chamber to the microwave generator is carrying momentum along with the energy.  If there's a poor match between feed line and resonator, photons bouncing back and forth may carry momentum far in excess of a single transfer of the energy.  This can be a problem for experimental integrity if the microwave generator is not on the force balance.
The null test should have also had similar error?

Title: Re: EM Drive Developments
Post by: su27k on 08/10/2014 03:18 PM
Dr White's presentation on this recent work: http://new.livestream.com/accounts/4950775/events/3217776/videos/58616741, starts after 52 mins.
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/11/2014 04:09 AM
thanks for the link. i will actually watch the thing through later but from the description you gave it seems nothing new has happened since his last recorded presentation.


i was just thinking...

if Mach's principle worked via advanced waves and retarded waves as opposed to quantum flux or one of the other ideas... would that not mean that you also have an ansible because you could then modulate a mach drive so as to encode information in the advanced and retarded waves?
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/11/2014 08:45 AM
i think Dr White said more about the EM drive this time. including details of the test rig power, measurements, calibration and so forth. if you can bear the crappy sound quality and the guy apparently expiring from TB in the background there is a lot in there to satisfy critics.

on the warp thing: his teams is quantifying and accounting for false signals. and has set up type of test for the warp thing involving time of flight measurements for a second laser beam. these measurement regimes take place at the same time so that false positives that affect one method generally don't affect the other.
Title: Re: EM Drive Developments
Post by: Hanelyp on 08/12/2014 05:11 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241596#msg1241596">Quote from: GregA on 08/10/2014 05:20 AM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241499#msg1241499">Quote from: Hanelyp on 08/09/2014 08:52 PM</a>
The forces inside a resonant chamber should be balanced, except for the feed point.  The transmission cable connecting the resonant chamber to the microwave generator is carrying momentum along with the energy.  If there's a poor match between feed line and resonator, photons bouncing back and forth may carry momentum far in excess of a single transfer of the energy.  This can be a problem for experimental integrity if the microwave generator is not on the force balance.
The null test should have also had similar error?
Not if the dummy load presented a greatly different impedance than the active resonator.

Title: Re: EM Drive Developments
Post by: Star One on 08/12/2014 07:42 PM
Reading around in various places there seems to be quite a bit of growing support for thinking the Mach effect is at work here and at the same time Dr White's explanation seems to be under be a good deal of scrutiny of close scrutiny.
Title: Re: EM Drive Developments
Post by: GregA on 08/12/2014 09:42 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242328#msg1242328">Quote from: Hanelyp on 08/12/2014 05:11 PM</a>
Not if the dummy load presented a greatly different impedance than the active resonator.
Okay, at least I understand your thinking - that there was an error in measurement, and the control for it probably didn't work.

Title: Re: EM Drive Developments
Post by: peter-b on 08/12/2014 09:49 PM
The EMDrive folks approached my friends in the propulsion group at SSC about doing some experiments in the SSC propulsion lab. The EMDrive people refused to allow their drive to be tested using SSC's extremely sensitive laser thrust balance, and as a result the group told them to go elsewhere.

I've spoken a few of the propulsion group about the latest results: the consensus is poor methodology and/or experimental error.
Title: Re: EM Drive Developments
Post by: aceshigh on 08/12/2014 09:51 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242374#msg1242374">Quote from: Star One on 08/12/2014 07:42 PM</a>
Reading around in various places there seems to be quite a bit of growing support for thinking the Mach effect is at work here and at the same time Dr White's explanation seems to be under be a good deal of scrutiny of close scrutiny.

links to these discussions would be welcome :)

Title: Re: EM Drive Developments
Post by: Robotbeat on 08/12/2014 10:16 PM
Judging from the comments here, people don't seem to have much respect for just how HARD it is to get a truly solid result from a small signal and just how EASY it is to fool oneself. This is why we make scientists go to grad school and do real research. Getting VALID results from noisy data is a Herculean task, and at every single step, there's a temptation to interpret your noisy data as confirming your expectations or to remove "outliers" that can subtly tilt the odds in favor of your desired outcome. No outright fraud is necessary for this to happen! That's a common mistake that non-scientists make: if someone gets a false positive, it must be because of intentional fraud, the naive may say. But no, it's much subtler than that. Teasing out signals in noisy data is so easy to screw up. An enormous amount of self-skepticism is necessary or you will produce non-reproducible results (which are ultimately shown to be in error).

Or, in the words of Richard Feynman, "The first principle is that you must not fool yourself, and you are the easiest person to fool!"

Nature does not give up her secrets easily, and she doesn't care how much you want a certain thing to be true.


I would literally cut my arm off if doing so would make these results valid. But chances are, it's just a false positive. From a Bayesian perspective, because conservation of momentum and energy are so well established (and ways to keep conservation with these results equally unlikely), even a positive, "statistically significant" result (p<0.05) WITHOUT systematic error would almost certainly still be a false positive, by an enormous margin.
Title: Re: EM Drive Developments
Post by: Robotbeat on 08/12/2014 10:44 PM
In undergrad: "Huh, didn't work as I thought it would! What did I do wrong?..."
In grad school:"Huh, this result actually confirms my hypothesis! What did I do wrong?..."
Title: Re: EM Drive Developments
Post by: Star One on 08/12/2014 11:49 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242405#msg1242405">Quote from: aceshigh on 08/12/2014 09:51 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242374#msg1242374">Quote from: Star One on 08/12/2014 07:42 PM</a>
Reading around in various places there seems to be quite a bit of growing support for thinking the Mach effect is at work here and at the same time Dr White's explanation seems to be under be a good deal of scrutiny of close scrutiny.

links to these discussions would be welcome :)

Unfortunately quite a bit is on the Polywell forum & I am unsure about linking to that now as it heavily features what appears to be a banned member from here?

Title: Re: EM Drive Developments
Post by: aero on 08/13/2014 12:29 AM
Perhaps a different view is that on that forum there is a member loudly promoting his/her long held favorite theory. As he has been for a long time, loudly and often. He has won over a few converts.

I've no opinion about ME theory or the Woodward effect but I wouldn't promote it as "One size fits all." Neither would I say that there is no chance of it fitting as no one really knows.
Title: Re: EM Drive Developments
Post by: GregA on 08/13/2014 01:02 AM
Can anyone shed some light on the Chinese research done a couple of years ago, finding a greater effect, and flaws in that?
Title: Re: EM Drive Developments
Post by: aero on 08/13/2014 01:46 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242440#msg1242440">Quote from: GregA on 08/13/2014 01:02 AM</a>
Can anyone shed some light on the Chinese research done a couple of years ago, finding a greater effect, and flaws in that?

A professional English translation of the paper Net thrust measurement of propellantless microwave thrusters*.

http://www.emdrive.com/yang-juan-paper-2012.pdf (http://www.emdrive.com/yang-juan-paper-2012.pdf)

Title: Re: EM Drive Developments
Post by: cuddihy on 08/13/2014 03:23 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242408#msg1242408">Quote from: Robotbeat on 08/12/2014 10:16 PM</a>

I would literally cut my arm off if doing so would make these results valid. But chances are, it's just a false positive. From a Bayesian perspective, because conservation of momentum and energy are so well established (and ways to keep conservation with these results equally unlikely), even a positive, "statistically significant" result (p<0.05) WITHOUT systematic error would almost certainly still be a false positive, by an enormous margin.

A third possibility (remote but more likely than violation of conservation of mass/momentum) is that of a non-confirming true positive -- that is a result that is not due to some kind of error in experiment but that is attributable to something (new) other than the tested theory. This is what those speculating on unintended Woodward effect as the cause of the thrust are pushing. It offers a (sounder) theoretical basis for "propellantless" thrust that does not require facial violation of established physics, only the swallowing of incredible results.

Another example of this type of possibility would be a never-before-observed directional coupling mechanism between the vacuum chamber and the feed lines... Some experiment failures are interesting in their own right.

Title: Re: EM Drive Developments
Post by: Star One on 08/13/2014 06:28 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242434#msg1242434">Quote from: aero on 08/13/2014 12:29 AM</a>
Perhaps a different view is that on that forum there is a member loudly promoting his/her long held favorite theory. As he has been for a long time, loudly and often. He has won over a few converts.

I've no opinion about ME theory or the Woodward effect but I wouldn't promote it as "One size fits all." Neither would I say that there is no chance of it fitting as no one really knows.

Thanks that's probably not a bad way of putting it on second thoughts. I don't know this person's history but it certainly seems a rather dominant poster on there.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/13/2014 07:25 AM
well if  the ME idea turns out to be valid there might be an Ansible in it for free. :)

of course accepting the ME idea there are several proposed mechanisms by which it could work. but if the ME is valid and it turns out to involve Freeman's advanced and retarded wave explanation then because inertia would be a result of communication with distal parts of the universe then you should be able to modulate an ME device output and send encoded information.
Title: Re: EM Drive Developments
Post by: Star One on 08/13/2014 10:11 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242482#msg1242482">Quote from: Stormbringer on 08/13/2014 07:25 AM</a>
well if  the ME idea turns out to be valid there might be an Ansible in it for free. :)

of course accepting the ME idea there are several proposed mechanisms by which it could work. but if the ME is valid and it turns out to involve Freeman's advanced and retarded wave explanation then because inertia would be a result of communication with distal parts of the universe then you should be able to modulate an ME device output and send encoded information.

I am not sure that's a very good idea to send out info to who knows what & where.:)

http://news.bbc.co.uk/1/hi/8642558.stm

Title: Re: EM Drive Developments
Post by: frobnicat on 08/13/2014 10:59 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242458#msg1242458">Quote from: cuddihy on 08/13/2014 03:23 AM</a>
Another example of this type of possibility would be a never-before-observed directional coupling mechanism between the vacuum chamber and the feed lines... Some experiment failures are interesting in their own right.

Making a fully rotationally symmetric apparatus would eliminate a whole range of possible failure modes : vertical cylindrical vacuum chamber with co-axial axis of rotation for the horizontal balance beam, thruster resonant cavity mounted on one end of the beam and counter weight at the other end (or better yet another identical fed resonant cavity). Ideally waveguide(s) injecting RF power and measuring reflecting waves also co-axial (cylindrical inlet freely rotating inside fixed feed line, with 0 friction small gap<<wavelength between). Any displacement would leave the whole moving system in an equivalent geometric situation relative to vacuum chamber frame of reference. Remaining failure modes, if apparent thrust is observed, would imply momentum transfers "transverse" from reference frame surfaces : my guess it's not impossible but much weaker effects that pushing orthogonally with pressures/varying volumes, assuming leaks or feed lines couplings (fields in varying volumes between moving parts and fixed parts).

For levels of power/thrust ratios of the order reported by the Chines experiment or R. Shawyer it should even be relatively easy to have a freely rotating beam with residual torque resistance much below the torque given by such net thrust. Let it accelerate and observe the thrust relative to speed...

One question : what is the difference between a cavity that is fed at its resonant frequency and a cavity that is fed with a different frequency, at same power levels ? My maybe incorrect understanding is that when resonance is present the different waves bouncing back and forth happen to "synchronize" in a standing wave where anti-nodes exhibit amplitudes Q (quality factor) times stronger than the incoming excitation. But from a photon point of view, you are just throwing photons in a cavity and the collective behaviour is just the sum of individual behaviours : whatever frequency (in a wide range) the photons will bounce back and forth on the order of Q times before being absorbed (dissipated) on walls, regardless of resonance or not. So for a given power input and given Q, EM energy density is the same, resonance or not, only the amplitudes don't sum up well when not resonant, please tell if wrong. My point is, if thrust effect is real it can't be about just classical linear EM waves bouncing back and forth in asymmetrical cavity : resonance wouldn't change the effect, while all of the proponents seem to imply resonance is central with their experiments.

Maxwell equations are linear, same with the ohmic losses (at skin depth in the cavity's walls). Specifically resonance would be necessary to reach fields strong enough to enter nonlinear effects ranges ? How the reached resonant amplitudes compares with known limits of linearity, dielectric strength for instance ?

Thank Aero for the link to english translation of the Chinese paper.

Title: Re: EM Drive Developments
Post by: aceshigh on 08/14/2014 06:02 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242477#msg1242477">Quote from: Star One on 08/13/2014 06:28 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242434#msg1242434">Quote from: aero on 08/13/2014 12:29 AM</a>
Perhaps a different view is that on that forum there is a member loudly promoting his/her long held favorite theory. As he has been for a long time, loudly and often. He has won over a few converts.

I've no opinion about ME theory or the Woodward effect but I wouldn't promote it as "One size fits all." Neither would I say that there is no chance of it fitting as no one really knows.

Thanks that's probably not a bad way of putting it on second thoughts. I don't know this person's history but it certainly seems a rather dominant poster on there.

he is not a dominant poster, and he fought with many forumers there. BUT we should not judge his ideas by his personality.

plenty of forumers there ARE on Woodwards emailing list.


Also bear in mind there is a long long Mach Effect thread on that forum, where Paul March (who works with Dr White) and is known here on NSF as Stardrive) had many posts and long discussions.


93143 can talk about the situation too, since he is also a long time poster at Talk Polywell and here at NSF.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/14/2014 07:00 AM
hey, there is a new article at new scientist on CERN's hunt for monopoles. i am not a subscriber so i cannot access the full article. but if they find monopoles and can reproduce them in large numbers you could see materials that won't melt if you dunk them into a star or detonate a nuke on top of it. probably good stuff for rocket nozzles and high temperature and pressure reactor parts. even before that though exo-thermal reactions between monopole atoms would pack the power of a nuclear reaction in normal matter. if there were transparent monopole substances/elements (for example; monopole versions of silicon or quartz) you could have a window that is unbreakable even with relativistic impacts.
Title: Re: EM Drive Developments
Post by: Star One on 08/14/2014 09:22 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242902#msg1242902">Quote from: aceshigh on 08/14/2014 06:02 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242477#msg1242477">Quote from: Star One on 08/13/2014 06:28 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242434#msg1242434">Quote from: aero on 08/13/2014 12:29 AM</a>
Perhaps a different view is that on that forum there is a member loudly promoting his/her long held favorite theory. As he has been for a long time, loudly and often. He has won over a few converts.

I've no opinion about ME theory or the Woodward effect but I wouldn't promote it as "One size fits all." Neither would I say that there is no chance of it fitting as no one really knows.

Thanks that's probably not a bad way of putting it on second thoughts. I don't know this person's history but it certainly seems a rather dominant poster on there.

he is not a dominant poster, and he fought with many forumers there. BUT we should not judge his ideas by his personality.

plenty of forumers there ARE on Woodwards emailing list.


Also bear in mind there is a long long Mach Effect thread on that forum, where Paul March (who works with Dr White) and is known here on NSF as Stardrive) had many posts and long discussions.


93143 can talk about the situation too, since he is also a long time poster at Talk Polywell and here at NSF.

I meant dominant in the sense of being very active, poor choice of phrase perhaps by me.

Monopoles article as mentioned above.

http://www.newscientist.com/article/mg22329820.600-pole-alone-the-quest-for-a-north-without-a-south.html

I am subscriber but because of the paywall I cannot post the rest of it.

Title: Re: EM Drive Developments
Post by: sghill on 08/14/2014 04:21 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242503#msg1242503">Quote from: Star One on 08/13/2014 10:11 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242482#msg1242482">Quote from: Stormbringer on 08/13/2014 07:25 AM</a>
well if  the ME idea turns out to be valid there might be an Ansible in it for free. :)

of course accepting the ME idea there are several proposed mechanisms by which it could work. but if the ME is valid and it turns out to involve Freeman's advanced and retarded wave explanation then because inertia would be a result of communication with distal parts of the universe then you should be able to modulate an ME device output and send encoded information.

I am not sure that's a very good idea to send out info to who knows what & where.:)

http://news.bbc.co.uk/1/hi/8642558.stm

That Ansible would help explain the Fermi Paradox! 

I have a general magnetism question that this thread has made pop into my mind.  How can magnets attract or repel each other indefinitely without expending energy? If I put two ring magnets on a pole with the same pole facing each other, the magnet on the top will float above the magnet on the bottom, the repulsive force overcoming gravity, and the equilibrium distance between the two is determined by the field strength of the magnets. All that is well and good, but how does this happen without the repulsive (or attractive) effect fading over time and the magnets getting warm or otherwise emitting photons?  In other words, the floating magnet is continually resisting an accelerative force due to gravity, so it (and the other magnet) has to expend energy to counter gravity for it to stay afloat.  So where does that continual input energy come from? Even if it's at the nuclear level, there has to be an expenditure somewhere in order to negate gravitational acceleration.

Title: Re: EM Drive Developments
Post by: Robotbeat on 08/14/2014 06:56 PM
Conceptually, it's the same as a book lying on a desk. Desk is exerting a force on the book to counteract gravity but no energy is expended. Energy is force times distance. If a force is exerted on an object but the object doesn't move, no energy need be expended.
Title: Re: EM Drive Developments
Post by: JasonAW3 on 08/14/2014 07:02 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243039#msg1243039">Quote from: sghill on 08/14/2014 04:21 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242503#msg1242503">Quote from: Star One on 08/13/2014 10:11 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1242482#msg1242482">Quote from: Stormbringer on 08/13/2014 07:25 AM</a>
well if  the ME idea turns out to be valid there might be an Ansible in it for free. :)

of course accepting the ME idea there are several proposed mechanisms by which it could work. but if the ME is valid and it turns out to involve Freeman's advanced and retarded wave explanation then because inertia would be a result of communication with distal parts of the universe then you should be able to modulate an ME device output and send encoded information.

I am not sure that's a very good idea to send out info to who knows what & where.:)

http://news.bbc.co.uk/1/hi/8642558.stm

That Ansible would help explain the Fermi Paradox! 

I have a general magnetism question that this thread has made pop into my mind.  How can magnets attract or repel each other indefinitely without expending energy? If I put two ring magnets on a pole with the same pole facing each other, the magnet on the top will float above the magnet on the bottom, the repulsive force overcoming gravity, and the equilibrium distance between the two is determined by the field strength of the magnets. All that is well and good, but how does this happen without the repulsive (or attractive) effect fading over time and the magnets getting warm or otherwise emitting photons?  In other words, the floating magnet is continually resisting an accelerative force due to gravity, so it (and the other magnet) has to expend energy to counter gravity for it to stay afloat.  So where does that continual input energy come from? Even if it's at the nuclear level, there has to be an expenditure somewhere in order to negate gravitational acceleration.

Actually, I think all the Aliens out there are mad at us for not trying to contact them sooner...  Kind of like when you don't call your family for a while and they give you the cold shoulder...

Title: Re: EM Drive Developments
Post by: sghill on 08/14/2014 07:16 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243133#msg1243133">Quote from: Robotbeat on 08/14/2014 06:56 PM</a>
Conceptually, it's the same as a book lying on a desk. Desk is exerting a force on the book to counteract gravity but no energy is expended. Energy is force times distance. If a force is exerted on an object but the object doesn't move, no energy need be expended.

Thanks for responding!

How can a force be exerted without expending energy? (serious question). If I hold my fat aunt above my head and she doesn't move, I'm still using energy to exert a force to counter gravity.  Aren't atoms and particles doing the same?  Inversely, can't I also expend energy to squeeze them together until the atoms can no longer resist fusing and then lots of their energy is released.  Is the energy expended still zero until the whole thing collapses?

Title: Re: EM Drive Developments
Post by: frobnicat on 08/14/2014 10:04 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243137#msg1243137">Quote from: sghill on 08/14/2014 07:16 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243133#msg1243133">Quote from: Robotbeat on 08/14/2014 06:56 PM</a>
Conceptually, it's the same as a book lying on a desk. Desk is exerting a force on the book to counteract gravity but no energy is expended. Energy is force times distance. If a force is exerted on an object but the object doesn't move, no energy need be expended.

Thanks for responding!

How can a force be exerted without expending energy? (serious question). If I hold my fat aunt above my head and she doesn't move, I'm still using energy to exert a force to counter gravity.  Aren't atoms and particles doing the same?  Inversely, can't I also expend energy to squeeze them together until the atoms can no longer resist fusing and then lots of their energy is released.  Is the energy expended still zero until the whole thing collapses?

As Robotbeat states, no energy need be expended, that don't mean any "agency" that holds a force (on an object that doesn't move relative to the agent exerting said force) wont dissipate energy : muscles do use metabolic energy even when they are not doing useful work, as is the case when contracting without displacement. The same would apply for a DC electric motor exerting a torque on a stuck shaft, no displacement implies no useful work, yet the motor is dissipating energy. In both cases the whole energy used by the agent is completely converted to heat, while if displacement is done in the same direction as force then at least a fraction of the expended energy goes into useful work, like for instance gaining height (more gravitational potential energy for the pushed object) or speed (more kinetic energy). Said useful work's corresponding energy can be recovered later, that is converted to other forms...

A solid "passive" object like a chair can hold a force on an object without expending any energy but it cant follow displacement in the direction of force, if aunty is an inch above chair then chair is no longer exerting force on aunty : no energy needed to exert force but no useful work can be done. In general : useful work is less or equal to expended energy. No expended energy implies no useful work, useful work implies expended energy, but it's possible to expend energy without useful work (in which case efficiency is 0, and expended energy is dissipated as heat).

Like with a chair, you could keep two nucleus (say two deuterium) at a close distance by applying a static force opposite to the electrostatic repulsion, without expending any energy, but the electrostatic repulsion wouldn't get tired because it's not expending energy either. On the other hand to take two nucleus from the "long" distance you find them and get them to the closer distance you wish, your squeezing force has to exert through a displacement : that needs expending energy. More energy can be recovered when the two nucleus fuse together (strong nuclear force bigger than electrostatic repulsion at close ranges) but that's another story, you have to invest initial energy to get (not to keep) nucleus close first.

Now the confusing thing at microscopic scale is that there is no such thing as a solid object. Solidity is a consequence of chemical bonds : electromagnetic forces mediated by constant exchanges of photons. That don't sound really static and yet no net expenditure of energy is needed when no displacement is done overall. Even if talking about inflatable chair and all gas atoms keep moving around, they support aunty "for free" as far as energy is concerned, they don't get tired.

Title: Re: EM Drive Developments
Post by: SteveKelsey on 08/14/2014 11:26 PM
Regrettably coercivity dashes all hopes.

http://en.m.wikipedia.org/wiki/Coercivity

It is a cruel universe
Title: Re: EM Drive Developments
Post by: Req on 08/15/2014 02:06 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243242#msg1243242">Quote from: SteveKelsey on 08/14/2014 11:26 PM</a>
Regrettably coercivity dashes all hopes.

http://en.m.wikipedia.org/wiki/Coercivity

It is a cruel universe

So coercivity seems to imply that there is a fixed amount of time that it will levitate the other magnet, and whatever is actually responsible for the levitation will dissipate as heat over time.  Right?  No magic involved, something is being spent.

Title: Re: EM Drive Developments
Post by: Robotbeat on 08/15/2014 02:11 AM
Not necessarily if it's a superconductor! :)
Title: Re: EM Drive Developments
Post by: frobnicat on 08/15/2014 09:53 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243296#msg1243296">Quote from: Req on 08/15/2014 02:06 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243242#msg1243242">Quote from: SteveKelsey on 08/14/2014 11:26 PM</a>
Regrettably coercivity dashes all hopes.

http://en.m.wikipedia.org/wiki/Coercivity

It is a cruel universe

So coercivity seems to imply that there is a fixed amount of time that it will levitate the other magnet, and whatever is actually responsible for the levitation will dissipate as heat over time.  Right?  No magic involved, something is being spent.

Again : theory (classical or quantum mechanics) states that it is not necessary to spend energy to hold a force in a geometrically static (no displacement) system, even when the force is at distance (and at microscopic scale even a solid contact is in fact force at distance). Not necessary don't mean that any way to achieve such force won't show some level of power loss or wear or creep deformation or weakening. A block of iron supporting an object of one pound will exert a force (against the weight of object) and maintain its altitude forever without spending anything : no magic involved, force without displacement needs no net energy expenditure. Force is not energy. The "forever" is true on cosmological scales, at least a few billion years, after what dark energy could maybe start to rip space-time apart at mundane scales. Resting without spending energy, quite literally until the end of time : no magic involved.

There is no theoretical reasons (basic principles) why a magnetically "levitating" object would require more energy that an object resting on a solid block, actually the object is also "levitating" in the later case, only a few angstroms above the support.
See "contact force" on wikipedia :
Quote
The interaction between macroscopic objects can be roughly described as resulting from the electromagnetic interactions between protons and electrons of the atomic constituents of these objects. Everyday objects do not actually touch each other; rather, contact forces are the result of the interactions of the electrons at or near the surfaces of the objects (exchange force).

So there is nothing much special between just resting on a solid object (no energy needed, forever) and resting on a magnetic repulsion from a permanent magnet at longer distance : theoretically no energy needed. If you keep the fields well below coercivity limits and use appropriate materials this is also possible in practice. Demagnetization occurs mainly not as a function of time but of external magnetic field strength, that is below a certain level of external field the demagnetization time approaches infinity.
http://www.magmamagnets.com/permanent-magnet-stability (http://www.magmamagnets.com/permanent-magnet-stability)
Quote
The effect of time on modern permanent magnets is minimal. .../... Over 100,000 hours, these losses are in the range of essentially zero for Samarium Cobalt materials...
Also for a very very long functioning, some environmental radiation can wear the magnets :
Quote
SmCo exhibits significant demagnetization when irradiated with a proton beam of 10^9 to 10^10 rads
. I guess cumulative radiations would also discharge the current loops in a superconductor...

So, granted the opposite magnets levitation is more difficult to achieve and "fragile" than the levitation of just resting on a solid support but in both cases spent energy is 0, without magic involved. Of course if you used (not superconducting) electromagnets instead of permanent magnets then maintaining the force would need constant energy flow (power), but not out of basic principles fatality, just as a consequence of a technological choice. It's always possible to use more energy than needed.

Title: Re: EM Drive Developments
Post by: Mulletron on 08/16/2014 07:14 AM
My interpretation of the Nasa description of the test campaigns tells me that the shape of the thruster and the q factor make no difference. The presence of the dielectric and the electromagnetic flux are key. If it really works, it's due to photon momentum transfer described by Minkowski et al. Also describing quantum vacuum particle pair production / annihilation as a plasma is gobbledygook. The quantum vacuum is key here though, as it is the only way I can think of to bring about an asymmetry which would allow thrust to occur, and not have a violation of laws of thermodynamics. Just as the qv is responsible for the lamb shift observed in a shift in the energy levels of hydrogen atom atoms, I think the thruster may work in a similar but reverse way. A net thrust cannot occur via photon momentum transfer within the same frame of reference, but it could if energy could be transferred to another frame of reference. No violation of laws, net thrust. If this works, it could be describing a key asymmetry which could point to new physics. There are a lot of papers describing mechanisms similar to this, check out works by Feigel, Dewar, Millis (Nasa), Brito. I think this thruster would work best if it were just a tube with a dielectric slug of PVDF instead of PTFE, pumped with a huge amount of wideband RF white noise.
Title: Re: EM Drive Developments
Post by: Mulletron on 08/16/2014 09:23 AM
Since the emdrive isn't expelling anything, there isn't anything in our frame of reference to allow a symmetrical reaction to occur, like a rocket blast creating an equal and opposite reaction, giving you thrust. If it were expelling something, like the radiation it is producing, it would merely be a photon thruster. But it isn't expelling anything, so imagine a rocket with the cone capped off, no reaction.  This is where the dielectric comes in, it is providing a vector through to another frame of reference, that of the qv (composed of the ground states of all particles, all fields, all frequencies, which luckily fluctuates according to the uncertainty principle) and most importantly, another frame of reference. There the photons can interact and transfer some of their energy/momentum only fleetingly and achieve thrust. Fleetingly in that there is a very low probability of any interaction whatsoever. The dielectric serves to up a photons chances of interacting with the qv, nothing more. Some geometries and materials allow for repulsive Casimir effects. Just shooting RF out the back of the thruster will interact with something once in a very long while and give you a tiny bit of thrust. It looks like the dielectric ups those chances of an interaction some 16000 times. In the end everything is conserved, the energy is transferred to another frame of reference, reacts, and thrust occurs against the very weakly interacting qv. This isn't a reactionless thruster. So to improve the design, we need to improve our chances of interacting with the qv, which has a very low probability wave function, hence a low probability of ever being interacted with. Advanced materials, like PVDF (love this stuff), coupled with a very high power rf field at a frequency where the dielectric constant of the material is highest (permittivity peaks and dips at different frequencies), taking into account that the higher the frequency, the higher the photon energy. So using the highest frequency possible where the dielectric constant is highest, coupled with noisy high rf wideband power should be the ticket. #IFLScience
Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/16/2014 09:34 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243723#msg1243723">Quote from: Mulletron on 08/16/2014 07:14 AM</a>
it could if energy could be transferred to another frame of reference. No violation of laws, net thrust.

Frames of reference aren't physical entities.  You can't transfer energy or momentum or anything from one frame of reference to another.

Frames of reference are just different ways of observing exactly the same physical events.  Think of them as places observers could be to watch.  Relativity tells us that exactly the same rules are followed in all inertial frames of reference.

Talking about transferring energy to another frame of reference doesn't make any more sense than saying I can accelerate by pushing against my own shadow.  It's like saying I'm going to work on extracting energy from the number 3.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/16/2014 09:51 PM
The CMB frame of reference is a physical entity.
Title: Re: EM Drive Developments
Post by: Robotbeat on 08/16/2014 10:11 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243892#msg1243892">Quote from: IslandPlaya on 08/16/2014 09:51 PM</a>
The CMB frame of reference is a physical entity.
says some guy on the Internet?

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/16/2014 10:12 PM
Says me, yes.
Think about it carefully.
When you have, get back to me.
 :)
Title: Re: EM Drive Developments
Post by: frobnicat on 08/17/2014 12:04 AM

The mean local velocity (or momentum) vector of a relatively homogeneous flow of real particles (known or unknown) can define a local frame of reference, and you can conceivably transfer momentum from a device to such a flow, would that phrase be more accurate ? Known flows include solar wind, photon flows near hot objects, photon flow of the CMB, photons mediating planetary magnetic fields, wind (in atmospheres)... Undetected but suspected flow would include dark matter, cosmic neutrino background, gravitational waves . Other possible unknown fields are well, unknown. Obviously inside the walls of a vacuum chamber in an earth lab a number of those flows are ruled out.

Virtual particles of the vacuum on the other hand don't appear to define a frame of reference, though they might define an "inertial reference" (tm) : Casimir effect for instance don't show different behaviour on different inertial frames (Lorentz invariant, no reference of what would be an absolute 0 speed relative to vacuum) while dynamical Casimir effect allows to measure acceleration in absolute terms (can tell an absolute 0 acceleration relative to it). Don't know when gravity comes into play but in a flat space-time it seems hard to push on such a "medium" without breaking conservation of energy because of acquiring a reaction mass always at 0 speed relative to it (cost don't depend on a varying relative speed as would be the case with a real flow). So if energy is gained it would imply either to abandon conservation (and time invariance) or to tap into vacuum zero-point energy, which would no longer be zero-point... My guess is that all this virtual agitation down there is like a thermal bath and nothing useful (in terms of net work) can come out of it (second principle...) but please someone qualified help. If no useful work can be taped, then no cheap momentum exchange can be taped. The only help of virtual particles is when they come real but that needs same amount of energy/mass you would have to throw backward anyway to get momentum forward in classical reaction propulsion.

I'd like to see some qualified explanations with Feynman diagrams showing how it's impossible to push on virtual particles (unless they are made real at equivalent energy/mass cost).

Quote
It's like saying I'm going to work on extracting energy from the number 3.
You could still extract energy from the work of trying, couldn't you ?

Title: Re: EM Drive Developments
Post by: Robotbeat on 08/17/2014 03:22 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243899#msg1243899">Quote from: IslandPlaya on 08/16/2014 10:12 PM</a>
Says me, yes.
Think about it carefully.
When you have, get back to me.
 :)
The CMB is a certain reference frame (just like another reference frame), but why the crap should you be able to push against it or whatever you're talking about? There is no "ether."

frobnfiahdfh:
The virtual particles work the same in every reference frame. And you COULD "push" on them, if you wanted to expend the necessary energy to make them real particles, but that'd be no more efficient than a photon drive.

Title: Re: EM Drive Developments
Post by: JPLeRouzic on 08/17/2014 09:00 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243192#msg1243192">Quote from: frobnicat on 08/14/2014 10:04 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243137#msg1243137">Quote from: sghill on 08/14/2014 07:16 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243133#msg1243133">Quote from: Robotbeat on 08/14/2014 06:56 PM</a>
Conceptually, it's the same as a book lying on a desk. Desk is exerting a force on the book to counteract gravity but no energy is expended. Energy is force times distance. If a force is exerted on an object but the object doesn't move, no energy need be expended.

Thanks for responding!

How can a force be exerted without expending energy? (serious question). If I hold my fat aunt above my head and she doesn't move, I'm still using energy to exert a force to counter gravity.  ...
...
A solid "passive" object like a chair can hold a force on an object without expending any energy but it cant follow displacement in the direction of force, if aunty is an inch above chair then chair is no longer exerting force on aunty
If you pardon me the explanation of "energy equal force multiplied by distance and there is no distance involved", in my opinion of a layman is not enough to answer to "how a force can be exerted without expending energy". Actually it seems to me more a tautology than an explanation.
- It assumes an empty universe where two elements are considered in a static way. Using the concept of force is meaningless in this situation as they do not move, and by definition no energy is involved so IMO there is no explanation given. The key answer lies in energy budget in several states, including potential energy in its magnetic and gravitation aspects. Work is one form of energy, but there are many other forms, ultimately energy is a scalar, a quantity without direction attached contrary to a force which as a vector has a direction, and it is linked to the notion of mass. The energy concept is usefull to describe situations like the one proposed by sghill, as because by definition it is conserved from one state to the next, it easy to trace how it is transfered from one element to the other.
- If on earth we have a book at rest on a desk, it has more energy than the same book on the floor i.e. if it falls its energy could be transfered to another device. The desk do not fall because the manufacturer did put energy in it, and if you go as far as that, by assembling atoms, atoms can store energy at different places. When the book is put upon the desk, the desk and the book atoms store the gravitational potential energy of the book. If you remove the desk, the book last potential energy gain will be released and the book will fall to the next lower energy level (on the ground).
- It's the same for the two magnets of sghill, one is above the other, so this one has more potential energy, where does it comes? As the first magnet was put above the other, it gained in potential energy from the hand of the person who did it.
It can only goes down by sghill design and the other magnet pushes back on it, so where is the potential energy stored? It is in the atoms magnetic field. This is not free energy because energy had been initially used to magnetized those magnets, and the magnets do not permanently loose or gain energy when they are close to each other, because the previous energy budget will be restored as they will be pulled apart.

Indeed I am not a scientist, so I may be entirely wrong.

Title: Re: EM Drive Developments
Post by: frobnicat on 08/17/2014 09:27 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243978#msg1243978">Quote from: Robotbeat on 08/17/2014 03:22 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243899#msg1243899">Quote from: IslandPlaya on 08/16/2014 10:12 PM</a>
Says me, yes.
Think about it carefully.
When you have, get back to me.
 :)
The CMB is a certain reference frame (just like another reference frame), but why the crap should you be able to push against it or whatever you're talking about? There is no "ether."

CMB photons do carry momentum so it might be possible to either sail relative to them or push on them but it's so weak I guess it's irrelevant for practical propulsion, better just make the photons onboard.
Quote
Energy density of CMB is ~1eV/cm-3, comparable to that of starlight in the Milky Way.
http://www.astronomy.ohio-state.edu/~dhw/A873/notes4.pdf (http://www.astronomy.ohio-state.edu/~dhw/A873/notes4.pdf)
Also those photons don't make it past an experiment chamber walls.

Quote
frobnfiahdfh:
The virtual particles work the same in every reference frame. And you COULD "push" on them, if you wanted to expend the necessary energy to make them real particles, but that'd be no more efficient than a photon drive.

Completely agree, unless whole contemporary physics turned on its head. Precisely what I meant was "work the same in every inertial reference frame".
frobnfiahdfh ?

Title: Re: EM Drive Developments
Post by: frobnicat on 08/17/2014 10:10 AM
JPLeRouzic :
I can't find simple ideas to explain why energy = force x distance, all other ways to define energy relative to force would fail empirically so we could only relate that to convincing experiments and sensible definitions, or we could be deriving this "rule" from more basic principles (microscopically there is no "force", only momentum exchanges between bosons and fermions) that themselves would have to be admitted or understood from less mundane experiments...

My example of a passive object with a supporting force that don't "follow displacement" wanted to avoid the potential energy complexities involved with springs and possible oscillations around an equilibrium, maintaining the macroscopic equilibrium point by itself needing no net energy spending while quite a lot of energy can be buzzing around. Microscopic thermal agitation is a perpetual motion after all, the bottom of energy, where useful energy is "lost" as heat. Apart from the strange musings about "2 elements considered a static way in empty universe" I don't understand, the rest of what you say makes perfect sense and seems correct to me.

But how does this "force with no net spent energy" point relates to the topic ? A thruster has to exert a force through displacement (in any inertial frame since you also want to accelerate) so the distance term can't be 0 and spent energy can't be 0 either.

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/17/2014 11:28 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243892#msg1243892">Quote from: IslandPlaya on 08/16/2014 09:51 PM</a>
The CMB frame of reference is a physical entity.

No.

The CMB is a physical entity.  There is a reference frame associated with it.  That doesn't make the reference frame a physical entity.

There is also a reference frame associated with the Earth.  It's just the frame in which the Earth is at rest.  That doesn't make the reference frame a physical entity you can transfer energy to or from.  You can transfer energy to and from the Earth.  You cannot transfer energy to and from the Earth's reference frame.

Again, it's like confusing the number 3 with a physical object.  It's like saying I'm going to construct three spaceships that have a shared drive that transfers momentum to the number 3 and thus produces thrust.  The fact that the number three is associated with something physical (three spaceships) doesn't make the number three a physical object, even though there are physically three spaceships.

You're really not helping your case for the plausibility of the EmDrive by displaying a profound misunderstanding of the most basic concepts of high school physics.

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/17/2014 11:43 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244020#msg1244020">Quote from: JPLeRouzic on 08/17/2014 09:00 AM</a>
If you pardon me the explanation of "energy equal force multiplied by distance and there is no distance involved", in my opinion of a layman is not enough to answer to "how a force can be exerted without expending energy". Actually it seems to me more a tautology than an explanation.

It's not a tautology or an explanation.  It's a definition.  It's the definition of the term "work" in physics.

It turns out that if we define work that way, it's a useful concept for predicting what will happen in the physical world.  It turns out that if you look at the work done combined with some other quantities, the sum never changes.  This is called conservation of energy.  Work is just one component of energy, really.

It seems strange that a force that isn't moving an object expends no energy only because it conflicts with many of our every-day experiences.  For example, if we push hard against a wall, we apply force to it, and there is no movement, but it tires us out to keep pushing.  So we think that we have to use up energy to keep a force applied even when there is no movement.

But we're fooled in this case, because work is being done, we're just not seeing it.  That energy is turning into heat, which is just movement of molecules.

So, when we try to apply a force directly with our muscles, we have to expend energy even if there is no obvious movement because we are causing lots of molecules to move around more quickly.

On the other hand, a magnet is a good example of an everyday object that can keep applying a force with no energy expended.  Put a magnet on your refrigerator and it will stay there for years.  It will keep applying a force to stick the magnet to the refrigerator, but no energy will be expended.

The magnet is capable of applying a force continuously without expending energy.  The magnet doesn't leak energy by causing something to heat up.  Your muscles are not capable of that.

Title: Re: EM Drive Developments
Post by: JPLeRouzic on 08/17/2014 01:39 PM
@Frobnicat: First I apologize, English is not my native language. Second: I understand your concern about this topic and how an explanation based on energy conservation could have been misinterpreted as validating the propellantless thruster. The difficulty indeed is that energy is poured in this device and something must happen. However given the very low level of thrust, I find it perfectly possible that this energy is dissipated as heat and therefore, given the assymetry of the device, it warms air more on one side than the other, hence the net thrust.

On contrary it seems to me, that it is impossible to use the conservation of energy as an explanation of the EM drive (or other propellantless thruster) as it would in this case produce much more thrust that people claim it does. A simple RC plane or a RC car use less power for a similar mass and gives visible results, no need for ad hoc extra sensible torsion pendulum  :).
 
@ChrisWilson68: I think that you may have not read my whole post and stop after the first phrase.

My point isn't that a magnet produces some energy, it does not indeed. It is that the given explanation is circular, and I provided another explanation based on energy conservation.
By the way I am sure a modern definition of energy is not "energy is force by distance". What is important and much more modern is that energy is conserved. It was on this premise that I gave my explanation.
Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/17/2014 02:05 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243892#msg1243892">Quote from: IslandPlaya on 08/16/2014 09:51 PM</a>
The CMB frame of reference is a physical entity.
I'll make no bones about it.
My assertion is wrong.
Thanks guys.

Title: Re: EM Drive Developments
Post by: Robotbeat on 08/17/2014 02:53 PM
Props for that, Island!
Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/18/2014 01:41 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243899#msg1243899">Quote from: IslandPlaya on 08/16/2014 10:12 PM</a>
Says me, yes.
Think about it carefully.
When you have, get back to me.

Just read the oracle.  Sheesh.

http://en.wikipedia.org/wiki/Cosmic_microwave_background

Still, a frame of reference is a different sort of physical entity than say, an apple, subject to gravity.

I keep thinking that there is an ether.  I'm just a nineteenth century guy, I guess.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/18/2014 01:41 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243039#msg1243039">Quote from: sghill on 08/14/2014 04:21 PM</a>
How can magnets attract or repel each other indefinitely without expending energy?

Nobody completely understands magnetism either.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/18/2014 01:42 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241490#msg1241490">Quote from: CW on 08/09/2014 08:19 PM</a>
No movement - no impulse. I mean, it is IMHO comparable to a book standing on a table. No-one would imply that the book were to 'violate' impulse conservation in any way ;) . So, what's going on here?

The area that Woodward is looking into regards having a better understanding of inertia.  Sciama holds a theory, based on Mach's work, that the entire universe immediately pushes back on the book, so that, in principle, one can discard the table entirely.  Basically, Woodward is attempting to convert electricity into momentum.  Electricity goes into his device, and then the device moves forward, if not otherwise bound by gravity.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/18/2014 01:42 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241476#msg1241476">Quote from: CW on 08/09/2014 07:42 PM</a>
I think one has to be careful when calling found physical principles 'laws'. They are not laws in the absolute sense, as in given by 'God', or being the final answer. The only thing we can say about the principles that we found and verified by peer-reviewed experiments up to any given point in time is: To the best of our current knowledge, this is what happens. A very important point to make.

Just want to add the observations of C.S. Peirce, who has suggested quite some time ago, that the "laws" of physics might be "habits", and that they change over time.

The gravitational constant, it turns out, is not exactly constant, but appears to vary.

I also want to point out that inanimate interpretations of the beginnings of the universe and evolution are as faith based as any other interpretations.

[Edit: Inadvertently forgot to include the important word "beginnings" of the universe, as was pointed out below.]

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/18/2014 01:42 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241380#msg1241380">Quote from: sanman on 08/09/2014 12:47 PM</a>
"But physics can't be bypassed," you say - well who can claim omniscient knowledge of physics? There may be small exploit opportunities which can be exposed here and there.

Then find them and exploit them.  At least Mr. Wooward is making an attempt.  By my reading, few physicists claim omniscient knowledge of physics.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/18/2014 01:42 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241310#msg1241310">Quote from: Stormbringer on 08/09/2014 06:13 AM</a>
i have seen people here pan fusion propulsion.; a likely possible near term advancement.

Fixed that for ya.

It is more likely that fission drive (Boom-boom Orion) is near term than fusion drive.  My objection continues to be the careless, unsubstantiated  use of the word "likely".

As to VaSIMIR, I'm a mite confused by all of your negatives:  It isn't that unlikely?  This drive is real, but it has not been scaled to the extent necessary to propel, say, MCT.  It is more "likely" to be a "near term advancement" than boom-boom Orion, the way I see it.

Title: Re: EM Drive Developments
Post by: Robotbeat on 08/18/2014 01:54 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244341#msg1244341">Quote from: JohnFornaro on 08/18/2014 01:41 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243039#msg1243039">Quote from: sghill on 08/14/2014 04:21 PM</a>
How can magnets attract or repel each other indefinitely without expending energy?

Nobody completely understands magnetism either.
(warning, language) http://m.youtube.com/watch?v=OvmvxAcT_Yc


And for the record, we understand magnetism quite well, thank you very much. A direct consequence of classical electrostatics and special relativity.

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/18/2014 02:40 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244345#msg1244345">Quote from: JohnFornaro on 08/18/2014 01:42 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241310#msg1241310">Quote from: Stormbringer on 08/09/2014 06:13 AM</a>
i have seen people here pan fusion propulsion.; a likely possible near term advancement.

Fixed that for ya.

It is more likely that fission drive (Boom-boom Orion) is near term than fusion drive.  My objection continues to be the careless, unsubstantiated  use of the word "likely".

As to VASIMR, I'm a mite confused by all of your negatives:  It isn't that unlikely?  This drive is real, but it has not been scaled to the extent necessary to propel, say, MCT.  It is more "likely" to be a "near term advancement" than boom-boom Orion, the way I see it.
let me fix it back then: Some fusion propulsion is likely near term both because there are a couple of fusion projects that lend themselves to propulsion and because politically you will see fusion in space well before Dr Chang Diaz gets enough to put more than a satellite booster sized test article on ISS if he ever gets the chance to do even that with slipping schedules, carriers and so forth.

EDIT I need to fix it again XD.

There is one fusion project blatantly stating they are working with NASA on a fusion engine. There are other fusion projects swinging at beating ITER. one of those has mentioned using it as a power source for electric propulsion. that onion layered reactor thing with the fancy spark plug (DPF.) it's not direct fusion drive but the power source for electrical or plasma propulsion. maybe even powering VASIMR.

Title: Re: EM Drive Developments
Post by: Star One on 08/18/2014 03:08 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244343#msg1244343">Quote from: JohnFornaro on 08/18/2014 01:42 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241476#msg1241476">Quote from: CW on 08/09/2014 07:42 PM</a>
I think one has to be careful when calling found physical principles 'laws'. They are not laws in the absolute sense, as in given by 'God', or being the final answer. The only thing we can say about the principles that we found and verified by peer-reviewed experiments up to any given point in time is: To the best of our current knowledge, this is what happens. A very important point to make.

Just want to add the observations of C.S. Peirce, who has suggested quite some time ago, that the "laws" of physics might be "habits", and that they change over time.

The gravitational constant, it turns out, is not exactly constant, but appears to vary.

I also want to point out that inanimate interpretations of the universe and evolution are as faith based as any other interpretations.

To expand on your comment above I see there are some theorists suggesting that gravity at the massive scale, for want of a better term may not be the same as gravity at a local level and that the search for dark matter & energy could be futile. The argument goes that these latter two were invented purely as a kludge in the theory to fit the observations.

Do we even if subconsciously seem somehow to risk slipping back into almost Ptolemaic terms sometimes when discussing the laws of physics?

Title: Re: EM Drive Developments
Post by: Mulletron on 08/18/2014 04:01 PM
A frame of reference is relative. Just a comparison to another system. It is not a physical thing. It is a physical system, be it thermodynamic, relativistic, quantum, non/inertial, whatever. A lot of folks just assume that when frames of reference are talked about, that it must be inertial. Moreover, a frame of reference is not a container of things, just a way of comparing what is happening here verses there. An interaction with another frame of reference is an interaction with the "things" in that other frame of reference. Of course you can't push against a number 3. Numbers are more epistemological than real. Lets not be obtuse here. That did bring back memories of comparisons I read about how information/energy/matter are equivalent though, and how an AND logic gate will convert that lost bit of information to heat energy, but I digress. I'm not writing about the philosophy of science.

So back to the thruster and how frames of reference are key.

I previously talked about two other qv interactions with matter, the Lamb Shift and Casimir. Here's another possible one. So I read into the controversial Unruh effect that says roughly, in an accelerating frame of reference, virtual particles observed outside your frame of reference (be it stationary or slower) may appear to become real particles. The vacuum of the stationary frame of reference as seen from the accelerating observer appears to contain some real particles. Now in your local yet accelerating frame of reference, virtual particles are there happening around you but aren't observed as "real." Meaning they don't stick around long enough to become real. Meaning you can't do jack with them. But there's hope. Thankfully because acceleration is relative, an observer outside of your frame of reference will see your virtual particles become real. That doesn't help us either, but the methodology is key. As you know, frames of reference are relative.

So I flipped it. How about this: We live in an accelerating universe. Our universe is accelerating at rates which we cannot ever hope to achieve. Furthermore, the rate of expansion is a curve, meaning galaxies further away are flying apart faster than the ones flying apart closer to us. Neat. So from the point of view of the universe, which is the accelerating frame of reference, our emdrive is accelerating slowly, compared to say the CMB frame of reference.

So lets imagine ourselves on a spaceship in Earth orbit and you are equipped with our brand new emdrive technology. From your frame of reference you are barely moving compared to the accelerating speed of universal expansion happening around you. So imagine yourself inside your space ship and you're looking intently at your prototype emdrive looking for real particles to appear out of the qv fluctuations, you don't see them. Now imagine the universe is the observer. The universe observing your emdrive would see some virtual particles from the qv becoming real. This only works if the universe is expanding. So with this mechanism, you get some arbitrary flux of real particles from the qv frame of reference (I'm assuming the qv and its randomly produced particle pairs are not inertially related to our inertial frame of reference) popping into your local frame of reference (as observed from the point of view of the universe). So I'm picturing the pair production happening randomly, becoming real, and immediately flying away at a rate matching the speed and direction of the expansion of the universe minus the influence of gravity, isotropically. My head hurts.

This next part I'm iffy on too: So since the universe has no center from where to measure expansion or acceleration against (correct assumption?), does it make any difference what the acceleration of the space ship is? Would accelerating the ship result in a gain in particle pair longevity? I don't think it becomes an issue until you get near relativistic speeds. Is it possible to accelerate, or are we already accelerating at a rate faster than the LOCAL expansion rate of the universe as seen within the bounds of the emdrive? Is gravity keeping the expansion of the universe in check at small scales? Would accelerating the ship increase the real particle longevity flux? I don't know. Maybe doesn't help anyway. All of this depends on whether the Unruh effect is real or not.

I personally don't have much confidence that this is what is happening, I'm just brainstorming this approach. I think the logic above would have us all awash in real particles all the time. Maybe that's where matter comes from, lol. Maybe that's what boggs us down when approaching the speed of light. The thoughts above concerning the Unruh Effect are just concerned with creating real particles to interact with and I believe the effect is probably small solely because it is controversial. I think it could be small part of what's happening. I read somewhere that a very large charge field within a highly polarized dielectric medium stimulates pair production, which could in turn become real. I think that most of the effect stems from directing the poynting vector of a very strong rf field down the axis of desired acceleration through a dielectric is causing a transfer of momentum in a way I don't fully understand. I disagree with the shape of the bell/pill box on the two drives tested as I think they are unnecessary. I think they should take design cues from coaxial cables, only terminating the end in a way to scavenge the rf for reuse back into the top of the thruster. I think a resonant standing wave doesn't do much for the thruster and that max rf energy flow is key. I'm picturing a bundle of cylinders arranged into a honeycomb shape, with rf distributed into the top and the other ends capped off with a door knob type of rf probe as a pick up. The energy density of the cmb peaks at around 160ghz. I'm not sure if a frequency matching it would be helpful or not. It would make for a very small wavelength, and all the design implications that go along with it.
Title: Re: EM Drive Developments
Post by: Stormbringer on 08/18/2014 05:24 PM
i didn't think Unruh was all that controversial anymore? i think I have seen it outside the usual speculative propulsion related stuff. i thought it was scientifically established?
Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/18/2014 05:46 PM
Just wanna add that we understand quantum mechanics "quite well" too.  Nobody claims complete knowledge of QM or magnetism.
Title: Re: EM Drive Developments
Post by: Robotbeat on 08/18/2014 06:02 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244542#msg1244542">Quote from: JohnFornaro on 08/18/2014 05:46 PM</a>
Just wanna add that we understand quantum mechanics "quite well" too.  Nobocy claims complete knowledge of QM or magnetism.
No, we understand exactly what's going on in magnetism. We also under QM fully, too, it's just very counter-intuitive. Just because you don't understand it and just because it takes a lot of effort to understand it doesn't mean it isn't understood.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 08/18/2014 08:12 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244552#msg1244552">Quote from: Robotbeat on 08/18/2014 06:02 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244542#msg1244542">Quote from: JohnFornaro on 08/18/2014 05:46 PM</a>
Just wanna add that we understand quantum mechanics "quite well" too.  Nobocy claims complete knowledge of QM or magnetism.
No, we understand exactly what's going on in magnetism. We also under QM fully, too, it's just very counter-intuitive. Just because you don't understand it and just because it takes a lot of effort to understand it doesn't mean it isn't understood.
Nit picking.
We *don't* understand QM fully. It is obviously incomplete.
Gravity etc.

Title: Re: EM Drive Developments
Post by: frobnicat on 08/18/2014 11:45 PM
What we do know from innumerable experiments is that in a broad range of contexts QM is phenomenally accurate. This broad range includes all mundane particles, real or virtual, with energies up to a few 10s of Gev in any locally linearisable space-time. The fact that GR is a separate formalism doesn't prevent both theories taken together to be effective and precisely verified at predicting measurable outcomes in all but the most distant or artificially unattainable circumstances. The remaining phenomenological mysteries below extreme energies and/or gravitational curvatures might come from neutrinos or weakly interacting particles like dark matter, but they are precisely very weakly coupled to EM fields, otherwise their absence or uncertainties in theories would seriously limit the predicting power of SM which appear is not the case even with higher and higher precision measurements. There's still room for surprises, proton radius appear different when orbited by muon rather than electron. But overall the formalism looks solid and can accommodate extensions, as was and still is classical mechanics in its own range of validity. It's still insufficient by itself to mechanically tell all that can/will be done/discovered with arrangements of lot of particles (ie condensed matter properties...) at "emergent" scales but it certainly has some credit to tell that an arrangement of particles can't globally break a law that is experimentally shown to be respected at every single interaction point. There is a reason why some laws are called fundamental, and it's not a matter of scientists acting as prosecutors to enforce them, it's deeply embedded regularities of reality as it is observed.

So while we don't understand all QM at the frontiers of its validity and beyond, we do know quite well experimentally where the frontiers are, and while the interpretation of QM (the why or the what) is still hotly debated, the empirical predictive power speaks for itself and naturally entails much scepticism from mainstream physicists when a device consisting only of low density microwave photons bouncing around in ordinary matter claims either momentum conservation breaking or transferring momentum to vacuum (which in the later case is taping energy from the vacuum since vacuum is so far so very well experimentally confirmed to be inertial frame invariant).

Clearly if such thrust effects are worth investigating, then they are worth more than a week of a small team (speaking of the latest NASA experiment), and while I would say that they did a terrific experimental job given such a short time and limited resources, indulging themselves in "what if" scenarios of missions at the end of the paper does not serve them in terms of credibility : you can't write such a result and pretend to ignore how it is flying in the face of established physics before it flies to Mars, this is not serious and maintains the idea that such research is fringe science and not worth considerations. I wish despite this clumsiness they are granted more time and resources to either get a decent 0 net thrust measurement result, or a Nobel prize.
Title: Re: EM Drive Developments
Post by: Raj2014 on 08/19/2014 12:31 AM
Has there been any new news on the EM/Cannae drive?
Title: Re: EM Drive Developments
Post by: Robotbeat on 08/19/2014 01:01 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244654#msg1244654">Quote from: IslandPlaya on 08/18/2014 08:12 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244552#msg1244552">Quote from: Robotbeat on 08/18/2014 06:02 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244542#msg1244542">Quote from: JohnFornaro on 08/18/2014 05:46 PM</a>
Just wanna add that we understand quantum mechanics "quite well" too.  Nobocy claims complete knowledge of QM or magnetism.
No, we understand exactly what's going on in magnetism. We also under QM fully, too, it's just very counter-intuitive. Just because you don't understand it and just because it takes a lot of effort to understand it doesn't mean it isn't understood.
Nit picking.
We *don't* understand QM fully. It is obviously incomplete.
Gravity etc.
We don't have a theory of quantum gravity, but that'd be an extension of QM. QM itself we understand quite well and is complete. It doesn't have to be the theory of everything to be complete.

Anyway, I'm quitting this thread. In the words of Antares, I'm through arguing with amateurs. People want to skip learning regular physics that we already have a 100% understanding of and instead argue about fringe theories and physics beyond the standard model. It's ridiculous. You can't prove physics is wrong and incomplete until you actually understand physics! It's not like it's secret knowledge or something. The only reason people skip it is because they're lazy.

In a parting shot, I've seen this proposed as the Fourth Law of Thermodynamics:

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/19/2014 01:38 AM
 ;D  shamelessly stolen and stored for future use elsewhere. :)
Title: Re: EM Drive Developments
Post by: frobnicat on 08/19/2014 02:07 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244473#msg1244473">Quote from: Mulletron on 08/18/2014 04:01 PM</a>
A frame of reference is relative. Just a comparison to another system. It is not a physical thing. It is a physical system, be it thermodynamic, relativistic, quantum, non/inertial, whatever. A lot of folks just assume that when frames of reference are talked about, that it must be inertial.

Not necessarily inertial, but beware that inertial or not can be told locally without any outside reference, a simple accelerometer would suffice. So inertial frames are special. In an absolute sense.

Quote
.../... Thankfully because acceleration is relative, an observer outside of your frame of reference will see your virtual particles become real. That doesn't help us either, but the methodology is key. As you know, frames of reference are relative.

Inertial frames are relative, as proper time/distance transforms can translate observables of one frame into observables in the other. Well, I guess taking acceleration into account that is also possible for accelerated frames (introducing Coriolis "forces" for instance).

Quote
So I flipped it. How about this: We live in an accelerating universe. Our universe is accelerating at rates which we cannot ever hope to achieve. Furthermore, the rate of expansion is a curve, meaning galaxies further away are flying apart faster than the ones flying apart closer to us. Neat. So from the point of view of the universe, which is the accelerating frame of reference, our emdrive is accelerating slowly, compared to say the CMB frame of reference.

It's not clear what time derivative you are talking about : the rate of expansion (Hubble "constant") that goes as ~2.3e-12(m/s)/m (hey, it has dimension of a frequency !), or the change of this rate, which right now seems to be decelerating ( for a given distance you will see slower receding objects crossing this distance in the near future ) in spite of the mysterious acceleration of expansion (expansion not slowing as fast as it should, but still slowing from usual mass content gravity) ?
More confusing : the universe isn't locally accelerating, makes no sense, its local content has a local average speed that can be used as a local inertial frame of reference, but it is not accelerating in any absolute sense, there is nowhere special toward where it could accelerate ! The CMB is part of the content, take or give a few 100s km/s it's the same local inertial frame as the stars and gas averaged on a decently sized local patch, it goes with the flow, and this flow is 0 relative to receding neighbouring patches all around. Local universe is not accelerating if seen at coarse graining bigger than anisotropies. What particular direction of the sky the CMB is supposed to be accelerating (I'm not speaking of our galaxy relative velocity with CMB) ? And even if it were, it would just be free falling with us (say, with the local cluster) at the same acceleration toward a big lump in the neighborhood. Anyway it's not accelerating relative to us and relativity makes no difference between free-falling and inertial velocity in nothingness.

Quote
So lets imagine ourselves on a spaceship in Earth orbit and you are equipped with our brand new emdrive technology. From your frame of reference you are barely moving compared to the accelerating speed of universal expansion happening around you.

I'm barely moving relative to the speed of a specific cluster 1Bly away but in the walls of my ship, or even when considering the whole galaxy, the Universe could be static rather than expending wouldn't change a thing for me, how could a phenomenon occurring over cosmological times/distances could make any difference locally ?

Quote
So imagine yourself inside your space ship and you're looking intently at your prototype emdrive looking for real particles to appear out of the qv fluctuations, you don't see them. Now imagine the universe is the observer. The universe observing your emdrive would see some virtual particles from the qv becoming real. This only works if the universe is expanding.

What part of the universe is observing, my local patch average ? A co-orbiting inertial frame ? Earth ? Sun ? Galaxy ? None of those scales make any care of the fact that universe is expending, or that the rate of expansion varies a bit in a long while (sorry, can't find precise numbers here, but next to impossible to measure inside a lab, so making no difference for a ship).
 
Quote
So with this mechanism, you get some arbitrary flux of real particles from the qv frame of reference (I'm assuming the qv and its randomly produced particle pairs are not inertially related to our inertial frame of reference) popping into your local frame of reference (as observed from the point of view of the universe). So I'm picturing the pair production happening randomly, becoming real, and immediately flying away at a rate matching the speed and direction of the expansion of the universe minus the influence of gravity, isotropically. My head hurts.

I believe so. Trying hard and seriously to get your point but "matching the speed and direction" in one hand and "isotropically" the other seems like an oxymoron. Looks like your are longing for the inflation epoch when
a field of accelerated expansion (second order) was so strong it could everywhere rip apart virtual particles pairs to make them real. Would be compatible with the isotropy. Thing is, when such a field is so strong, reality tends to be not very stable and quickly evolves. We are in a stable epoch, stability of time prevents energy conservation breaking (as would be the case when virtual particles become real, note that the accelerating field is actually decaying, it loses some punch in the process). And stability of space (isotropy) prevents momentum conservation breaking. As per Noether's theorem.

Quote
.../... Is gravity keeping the expansion of the universe in check at small scales? .../...

Yes. Expansion observed now is just an inertial collective movement from initial expanding conditions. Gravitationally bound objects are not obliged to abide to Hubble law. The dark energy or lambda parameter on the other hand is supposed to act on metrics by "fabricating" more space between objects (while a relative inertial receding velocity don't really make more space per se), so if its pressure increases it could conceivably first alter then rip apart gravitationally bound objects. Local effects (at galaxy scale) are not expected to occur soon.
 
Quote
I think the logic above would have us all awash in real particles all the time. Maybe that's where matter comes from, lol.

Some think this is exactly what happened but not all the time, just at the end of the inflation when the inflaton field decayed into usual particles, and thus stopping inflation, see, this process can't last long. It's not stable.

Can't give other opinion for the rest as the Unruh effect is above my head, also I would tend to agree that resonance seems pointless (except maybe for efficiency of the coupling to the RF generator as the system must be analysed as a whole).


Title: Re: EM Drive Developments
Post by: su27k on 08/19/2014 05:24 AM
Jeff Foust has half an article on this in Space Review: http://www.thespacereview.com/article/2580/1, including a brief interview with White after his talk in Mars Society conference
Title: Re: EM Drive Developments
Post by: su27k on 08/19/2014 05:31 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244552#msg1244552">Quote from: Robotbeat on 08/18/2014 06:02 PM</a>
We also under QM fully, too

I think Feynman may disagree:

Quote
I think I can safely say that nobody understands quantum mechanics.

Title: Re: EM Drive Developments
Post by: Star One on 08/19/2014 06:25 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244791#msg1244791">Quote from: Mr. Scott on 08/19/2014 02:15 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244756#msg1244756">Quote from: Raj2014 on 08/19/2014 12:31 AM</a>
Has there been any new news on the EM/Cannae drive?
http://xkcd.com/1404/

Blimey people don't half like quoting that cartoon that's several times in this thread alone.:)

Anyway from what was in the report I don't think we'll be hearing any more too either much later this year but more likely next.

Quote from: su27k
Jeff Foust has half an article on this in Space Review: http://www.thespacereview.com/article/2580/1, including a brief interview with White after his talk in Mars Society conference

Thanks for that puts it in a better context. Funnily the reporting of this seemed more accurate at the start but as it became reporting of reporting it seemed to get more outlandish.

Title: Re: EM Drive Developments
Post by: Mulletron on 08/19/2014 03:03 PM

Quote

It's not clear what time derivative you are talking about : the rate of expansion (Hubble "constant") that goes as ~2.3e-12(m/s)/m (hey, it has dimension of a frequency !), or the change of this rate, which right now seems to be decelerating ( for a given distance you will see slower receding objects crossing this distance in the near future ) in spite of the mysterious acceleration of expansion (expansion not slowing as fast as it should, but still slowing from usual mass content gravity) ?
More confusing : the universe isn't locally accelerating, makes no sense, its local content has a local average speed that can be used as a local inertial frame of reference, but it is not accelerating in any absolute sense, there is nowhere special toward where it could accelerate ! The CMB is part of the content, take or give a few 100s km/s it's the same local inertial frame as the stars and gas averaged on a decently sized local patch, it goes with the flow, and this flow is 0 relative to receding neighbouring patches all around. Local universe is not accelerating if seen at coarse graining bigger than anisotropies. What particular direction of the sky the CMB is supposed to be accelerating (I'm not speaking of our galaxy relative velocity with CMB) ? And even if it were, it would just be free falling with us (say, with the local cluster) at the same acceleration toward a big lump in the neighborhood. Anyway it's not accelerating relative to us and relativity makes no difference between free-falling and inertial velocity in nothingness.


Hubble's Constant: H0 = 67.15 ± 1.2 (km/s)/Mpc. For every million parsecs of distance from the observer, the rate of expansion increases by about 67 kilometers per second.

The further away from the observer, you'll observe the velocity of galaxies increasing.

Title: Re: EM Drive Developments
Post by: frobnicat on 08/19/2014 04:20 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244947#msg1244947">Quote from: Mulletron on 08/19/2014 03:03 PM</a>

Hubble's Constant: H0 = 67.15 ± 1.2 (km/s)/Mpc. For every million parsecs of distance from the observer, the rate of expansion increases by about 67 kilometers per second.

The further away from the observer, you'll observe the velocity of galaxies increasing.

Yes, for every added meter distance you will see an added receding speed of about 2 picometers/second, it would be around 1m/s between Earth and Jupiter, but this is not an intrinsic law of the vacuum or space-time, just an average of inertial expansion from initial conditions and gravitationally bound "objects" like a galaxy don't see this effect within. Dark energy or accelerated expansion on the other hand appears to be intrinsic to space-time, but even if majority of energy content, its effect is very very weak on local scales, now and for the foreseeable future, so weak it is only slowing the slowing of expansion rate due to gravity, not yet accelerating it. Its only strength is it don't dilute like ordinary mass-energy content so it might win at the end. Until then its effect couldn't be detected locally inside a lab, even less used for any purpose.

The further away from the observer, you'll observe the receding velocity of galaxies increasing. Alright. Then taking the mean velocity of the galaxies all around at a given distance, you would see a residual relative velocity due to the velocity of our galaxy relative to average local content (say, CMB dipole, A few 100s km/s) but there is really no reason this velocity in the "neighbourhood frame as a whole" would accelerate. The neighbourhood is expanding but we (as any other content anywhere) are always like at the centre of this expansion, with no acceleration in any particular direction. And even if it did accelerate in a particular direction, what gives ? This would be like a free fall. A collection of free falling objects (not around a very compact object) don't make a distinction with just floating in nothingness.

And what is the relation of those far away galaxies and a ship orbiting Earth ? If we could build tethers out to 100s Mpc to grab onto receding neighbouring galaxies around, then we would surely have a good source of energy, and if dark energy holds that could even be a physically sound unlimited "free energy" source, albeit a little cumbersome. Short of that, what is our physical relation to those receding galaxies beyond a bunch of redshifted photons ?

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/19/2014 08:26 PM
according to Wheeler and Feynman and Ernst Mach we are tethered to everything all the way to the ends of the universe :) 

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/20/2014 02:42 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244552#msg1244552">Quote from: Robotbeat on 08/18/2014 06:02 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244542#msg1244542">Quote from: JohnFornaro on 08/18/2014 05:46 PM</a>
Just wanna add that we understand quantum mechanics "quite well" too.  Nobody claims complete knowledge of QM or magnetism.
No, we understand exactly what's going on in magnetism. We also under QM fully, too, it's just very counter-intuitive. Just because you don't understand it and just because it takes a lot of effort to understand it doesn't mean it isn't understood.

You confuse general or even detailed understanding with complete understanding.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/20/2014 02:59 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244405#msg1244405">Quote from: Stormbringer on 08/18/2014 02:40 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244345#msg1244345">Quote from: JohnFornaro on 08/18/2014 01:42 PM</a>

My objection continues to be the careless, unsubstantiated  use of the word "likely".

...Some fusion propulsion is likely near term both because there are a couple of fusion projects that lend themselves to propulsion ...

EDIT I need to fix it again XD.

There is one fusion project blatantly stating they are working with NASA on a fusion engine. ...

Unfortunately, you continue to misuse the term "likely".  Because "there are a couple of fusion projects that lend themselves to propulsion", and even "one fusion project blatantly stating they are working with NASA on a fusion engine" does not prove anything at all about the liklihood of these efforts succeeding in their experimental work.

I will make this prediction:  It is likely that there will be more fusion propulsion research projects in the future, and some of these might get substantial funding.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/20/2014 03:02 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244748#msg1244748">Quote from: frobnicat on 08/18/2014 11:45 PM</a>
What we do know from innumerable experiments is that in a broad range of contexts QM is phenomenally accurate. ...

This is a true statement. It does not go beyond what has been proven, nor does it suggest implausible warp drives.

Quote
So while we don't understand all QM at the frontiers of its validity and beyond, we do know quite well experimentally where the frontiers are...

Beyond those frontiers be dragons.

Quote
...indulging themselves in "what if" scenarios of missions at the end of the paper does not serve them in terms of credibility...

This is always done as a precursor to the never ending request for additional funding.  The request is not new, innovative, different, illegal, nor at all non-predictable.

I like your post.

Title: Re: EM Drive Developments
Post by: ChrisWilson68 on 08/21/2014 05:53 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244343#msg1244343">Quote from: JohnFornaro on 08/18/2014 01:42 PM</a>
I also want to point out that inanimate interpretations of the universe and evolution are as faith based as any other interpretations.

You obviously don't understand the difference between "faith based" and "evidence based".

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/21/2014 01:18 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1245585#msg1245585">Quote from: ChrisWilson68 on 08/21/2014 05:53 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244343#msg1244343">Quote from: JohnFornaro on 08/18/2014 01:42 PM</a>
I also want to point out that inanimate interpretations of the beginnings of the universe and evolution are as faith based as any other interpretations.

[Edit: Inadvertently forgot to include the important word "beginnings" of the universe, as was pointed out below.]

You obviously don't understand the difference between "faith based" and "evidence based".

Thanks for pointing out my inadvertent grammatical sloppiness, accompanied with the the bonus personal aspersion.

CW brought up a larger point, lost to Chris Wilson by my grammatical mistake:

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1241476#msg1241476">Quote from: CW on 08/09/2014 07:42 PM</a>
I think one has to be careful when calling found physical principles 'laws'. They are not laws in the absolute sense, as in given by 'God', or being the final answer. The only thing we can say about the principles that we found and verified by peer-reviewed experiments up to any given point in time is: To the best of our current knowledge, this is what happens. A very important point to make.

Quote from: jf
Just want to add the observations of C.S. Peirce, who has suggested quite some time ago, that the "laws" of physics might be "habits", and that they change over time.

The gravitational constant, it turns out, is not exactly constant, but appears to vary.

The physical principles discovered so far, fairly well understood by a small group of specialists, (not including Feynman) while accurately explaining some events, are not "laws" in some absolute sense.

As CW puts it, To the best of our current knowledge, this is what happens.  CW mentioned a common TLA, and I just riffed on that, pointing out that alternate faith based origination myths are not "absolute" either.

I'm guessing that the universe might very well be more Godelian than some might admit, but that's a personal guess of mine.

Every so often I take a goog on CS Pierce's idea that the universe's "laws" may only be "habits", but I haven't found any recent research on the idea.

There's also the either deliberate or poorly informed confusion between complete knowledge, and a sound working knowledge, mentioned above, again, in a n unnecessairly scathing personal tone.

In 1986, at least, it was not known about the relationship of QM and inertia.  From the abstract:

http://iopscience.iop.org/0264-9381/3/3/009

Quote
A new point of view towards the problem of the relationship between gravitational and quantum phenomena is proposed which is inspired by the fact that the distinction between quantum fluctuations and real statistical fluctuations in the state of a system seems not to be maintained in a variety of phenomena in which quantum and gravitational effects are both important. One solution to this dilemma is that quantum fluctuations are in fact real statistical fluctuations, due to some unknown, but universal, phenomena. At the same time quantum fluctuations have certain special properties which distinguish them from other types of fluctuation phenomena. The two most important of these are that the action of quantum fluctuations is non-dissipative for the special case of systems undergoing inertial motion in the absence of gravitational fields, and that the dispersion constant for quantum fluctuations for a particle is inversely proportional to the inertial mass of the particle. These properties are summarised in a set of principles which, it is proposed, govern the relationship between quantum phenomena, gravitation and inertia.

The author, Lee Smolin, coinvented "double special relativity". (soon to be a flavor at the Baskin-Robbins Institute)

Per the oracle:

http://en.wikipedia.org/wiki/Lee_Smolin#Experimental_tests_of_quantum_gravity

Quote
Smolin is among those theorists who have proposed that the effects of quantum gravity can be experimentally probed by searching for modifications in special relativity detected in observations of high energy astrophysical phenomena. These include very high energy cosmic rays and photons and neutrinos from gamma ray bursts. Among Smolin’s contributions are the coinvention of doubly special relativity (with João Magueijo, independently of work by Giovanni Amelino-Camelia) and of relative locality (with Amelino-Camelia, Laurent Freidel and Jerzy Kowalski-Glikman).

Thinking for a minute again about the notion of "complete" scientific understanding, Smolin is also interested in and has been working on, the foundations of QM.

Quote from: the oracle
Smolin has worked since the early 1980s on a series of proposals for hidden variables theories, which would be non-local deterministic theories which would give a precise description of individual quantum phenomena. In recent years, he has pioneered two new approaches to the interpretation of quantum mechanics suggested by his work on the reality of time, called the real ensemble formulation and the principle of precedence.

In fact, in 1992, he wrote a book about his idea of "cosmological natural selection", which sounds pretty interesting.  See the oracle for more info on that.

Susskind: "I'm not sure why Smolin's idea didn't attract much attention. I actually think it deserved far more than it got."

I feel his pain.  A prophet is never appreciated in his own time.

This wiki page is a great education, I think.  Know it alls, won't think so, I guess.

Quote
Since 2006, he has collaborated with the Brazilian philosopher and Harvard Law School professor Roberto Mangabeira Unger on the issues of the reality of time and the evolution of laws. ...

A book length exposition of Smolin's philosophical views appeared in April 2013...

Sounds like Smolin knows QM "quite well" but not "fully".  Sheesh.

I get tired of arguing with amateurs.

Title: Re: EM Drive Developments
Post by: Mulletron on 08/21/2014 02:30 PM
I'm seeing a lot about knowing qm quite well vs fully. This really is moot. It is a distraction from the subject at hand which is the emdrive or derivatives. It is the height of hubris to state you fully understand anything. If we fully understood qm or its offshoots, the subject would be closed, further study wouldn't be warranted and, we'd all be Doc Brown.
Title: Re: EM Drive Developments
Post by: SteveKelsey on 08/22/2014 06:50 AM
I like the notion, also expounded by Smolin I beleive, that physics is good at describing what happens, but not good at explaining what happens. The great precision with which QM describes events can be mistaken for accuracy in explaining what is going on.

Agreed this is getting away from Emdrive.
Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/22/2014 01:34 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1245705#msg1245705">Quote from: Mulletron on 08/21/2014 02:30 PM</a>
I'm seeing a lot about knowing qm quite well vs fully. This really is moot. It is a distraction from the subject at hand which is the emdrive or derivatives. It is the height of hubris to state you fully understand anything. If we fully understood qm or its offshoots, the subject would be closed, further study wouldn't be warranted and, we'd all be Doc Brown.

Absolutely.  I just get tired of reading the same assertions over and over.  EM drive doesn't work as they have explained the theory so far.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 08/22/2014 01:35 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1246021#msg1246021">Quote from: SteveKelsey on 08/22/2014 06:50 AM</a>
I like the notion, also expounded by Smolin I beleive, that physics is good at describing what happens, but not good at explaining what happens. The great precision with which QM describes events can be mistaken for accuracy in explaining what is going on.

Agreed this is getting away from Emdrive.

That Smolin page is most excellent.  I had heard of him, but yesterday was the first time I read about his work.  I would enjoy meeting him, if anybody here cares to set up the meeting.

Title: Re: EM Drive Developments
Post by: aceshigh on 08/22/2014 06:46 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244947#msg1244947">Quote from: Mulletron on 08/19/2014 03:03 PM</a>
Hubble's Constant: H0 = 67.15 ± 1.2 (km/s)/Mpc. For every million parsecs of distance from the observer, the rate of expansion increases by about 67 kilometers per second.

The further away from the observer, you'll observe the velocity of galaxies increasing.

a parsec = 3.2 ly

observable universe 12-13 billion light years... let´s consider it 13... 13 billion / 3.2 = 4 billion parsecs.

4 billion / 1 million = 4000

4000 * 67 = 268 thousand kilometers per second.

So at the edge of the universe, it is expanding almost at light speed away from us, right?

Title: Re: EM Drive Developments
Post by: MP99 on 08/22/2014 11:04 PM



<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1246253#msg1246253">Quote from: aceshigh on 08/22/2014 06:46 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1244947#msg1244947">Quote from: Mulletron on 08/19/2014 03:03 PM</a>
Hubble's Constant: H0 = 67.15 ± 1.2 (km/s)/Mpc. For every million parsecs of distance from the observer, the rate of expansion increases by about 67 kilometers per second.

The further away from the observer, you'll observe the velocity of galaxies increasing.

a parsec = 3.2 ly

observable universe 12-13 billion light years... let´s consider it 13... 13 billion / 3.2 = 4 billion parsecs.

4 billion / 1 million = 4000

4000 * 67 = 268 thousand kilometers per second.

So at the edge of the universe, it is expanding almost at light speed away from us, right?

Not "almost".

As we look at objects receding from us faster, they have a greater redshift. (This is an over simplification, but it's essentially correct.)

Once you reach the distance where Hubble expansion gives you recession at light speed, any light from there would undergo an infinite redshift, so it never reaches us. This is the definition of the edge of the "observable universe".

So, well spotted.

That edge is basically an event horizon, just like the boundary of a black hole.

BTW, the assumption is that the "observable" part of the universe may be a miniscule fraction of what was created from the big bang, in the same way that the universe outside a black hole is much bigger than the hole itself.

One big difference, though - an observer 10 billion light years away in our universe should also see a similarly-sized visible universe, but in a sphere centred on them. We share observability of lots of space, but they can see things that are beyond our horizon, and they can't see stuff that's distant from us in the opposite direction.

Every observer sees a different universe centred on them.

Cheers, Martin

Title: Re: EM Drive Developments
Post by: aero on 08/23/2014 02:37 AM
Oh - So my kid is right. He is the center of the universe. Oh well, I guess we are all the center of our own little, and our own big universe.
Title: Re: EM Drive Developments
Post by: Mulletron on 08/24/2014 12:48 PM
Just found this gem. Wanted to share it:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf

Seriously cool stuff. I'm in awe.
Title: Re: EM Drive Developments
Post by: Mulletron on 08/24/2014 01:02 PM
Full paper regarding recent NASA test campaigns of emdrive and cannae:

http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf


Anyone know any ways to increase the rate of quantum fluctuations and produce a greater flux of particle/antiparticle pairs? I got an indication earlier that this happens within dielectrics to a degree. (think it was the NASA slide show) Would a really strong electric charge field work, like in a capacitor across a dielectric? Could a strong enough electric field cause these virtual particle pairs to be ripped apart before they annihilate? If so, are these energy levels realistic or very high energy stuff? I know that high energy photon interactions with atomic nuclei can cause pair production if the energy of the photons is twice the rest mass of the particle, like for electrons, it is .511 MeV I think it was. So you need high energy photons. Any way to lower the energy requirement? A lower energy requirement would allow us to use lower frequencies. That's the goal I'm shooting for here. Radio frequencies instead of Gamma. Thoughts anyone?

Title: Re: EM Drive Developments
Post by: Avron on 08/24/2014 01:11 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1246965#msg1246965">Quote from: Mulletron on 08/24/2014 01:02 PM</a>
Thoughts anyone?

Not enough power,.. if 1Kw can make it vibrate.. 1 Mw should make it move

Title: Re: EM Drive Developments
Post by: Mulletron on 08/24/2014 01:26 PM
Well I can't see power being the major engineering problem here. I work with RF in my day job and power out isn't that big a deal, but higher frequencies, which equates to higher photon energies could be a problem. A waveguide for gamma rays, if you could contain them, would be very tiny. Focusing x-rays and gamma rays is a pain too.
Title: Re: EM Drive Developments
Post by: Avron on 08/24/2014 01:40 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1246970#msg1246970">Quote from: Mulletron on 08/24/2014 01:26 PM</a>
Well I can't see power being the major engineering problem here. I work with RF in my day job and power out isn't that big a deal, but higher frequencies, which equates to higher photon energies could be a problem. A waveguide for gamma rays, if you could contain them, would be very tiny. Focusing x-rays and gamma rays is a pain too.

Question,, has anyone measured the counter force, if any to the Sagnac effect?

Title: Re: EM Drive Developments
Post by: Mulletron on 08/24/2014 01:52 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1246972#msg1246972">Quote from: Avron on 08/24/2014 01:40 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1246970#msg1246970">Quote from: Mulletron on 08/24/2014 01:26 PM</a>
Well I can't see power being the major engineering problem here. I work with RF in my day job and power out isn't that big a deal, but higher frequencies, which equates to higher photon energies could be a problem. A waveguide for gamma rays, if you could contain them, would be very tiny. Focusing x-rays and gamma rays is a pain too.

Question,, has anyone measured the counter force, if any to the Sagnac effect?

I'm familiar with this concept from gyros. Basically you split a laser beam and make each travel around a half circle to a detector. If the circle rotates, one laser beam will travel a longer path and the other a shorter path, which is picked up at the detector. How does this apply here? What are you getting at?

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/24/2014 02:47 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1246970#msg1246970">Quote from: Mulletron on 08/24/2014 01:26 PM</a>
Well I can't see power being the major engineering problem here. I work with RF in my day job and power out isn't that big a deal, but higher frequencies, which equates to higher photon energies could be a problem. A waveguide for gamma rays, if you could contain them, would be very tiny. Focusing x-rays and gamma rays is a pain too.
if i understand correctly there has recently been a development in controlling gamma rays with meta materials or something like that. i vaguely recall something about meta-materials allowing lensing or refracting gamma rays and it having implications for smaller gamma ray telescopes and possibly other applications like lasers and so forth.

Title: Re: EM Drive Developments
Post by: Mulletron on 08/24/2014 02:56 PM
Another presentation by Dr. White:

http://www.astronautical.org/sites/default/files/vonbraun/2009/Von_Braun_Symposium_2009-10-21_7b_White.pdf

Title: Re: EM Drive Developments
Post by: Stormbringer on 08/25/2014 04:48 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1246965#msg1246965">Quote from: Mulletron on 08/24/2014 01:02 PM</a>
Full paper regarding recent NASA test campaigns of emdrive and cannae:

http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf


Anyone know any ways to increase the rate of quantum fluctuations and produce a greater flux of particle/antiparticle pairs? I got an indication earlier that this happens within dielectrics to a degree. (think it was the NASA slide show) Would a really strong electric charge field work, like in a capacitor across a dielectric? Could a strong enough electric field cause these virtual particle pairs to be ripped apart before they annihilate? If so, are these energy levels realistic or very high energy stuff? I know that high energy photon interactions with atomic nuclei can cause pair production if the energy of the photons is twice the rest mass of the particle, like for electrons, it is .511 MeV I think it was. So you need high energy photons. Any way to lower the energy requirement? A lower energy requirement would allow us to use lower frequencies. That's the goal I'm shooting for here. Radio frequencies instead of Gamma. Thoughts anyone?

well i remember a positron generator that used a laser to create a dynamical casimir mirror or other effect that produced and separated positrons (i guess they threw the electrons away or left them unused) so i have seen something like that. all the hooplah was over the fact that it would sit on half a desktop for a footprint. it was at one of the national labs.

Title: Re: EM Drive Developments
Post by: sghill on 09/02/2014 08:10 PM
OK,. I know we beat the heck out of this topic, but I had a thought over the weekend I wanted to float.

What if the EMDrives that Eagleworks tested were acting like a heat engine such as you'd find in a Crookes radiometer instead? 

If the microwaves imparted energy unevenly on the internal surface of the "thruster" and the test article, then it could generate the thrust as blackbody radiation warming air molecules just like in a Crookes radiometer that the torsion balance could have picked up.    http://en.wikipedia.org/wiki/Crookes_radiometer

They didn't test the things in a vacuum where this effect would not have occurred, which is why I thought it may be a possibility.
Title: Re: EM Drive Developments
Post by: Star One on 09/02/2014 09:10 PM
I thought it was tested in a vacuum chamber.
Title: Re: EM Drive Developments
Post by: QuantumG on 09/02/2014 09:13 PM
Radiometers do work in a vacuum, just not particularly well.
Title: Re: EM Drive Developments
Post by: MP99 on 09/02/2014 10:01 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1250335#msg1250335">Quote from: Star One on 09/02/2014 09:10 PM</a>
I thought it was tested in a vacuum chamber.
Yup, bat at 1 atmosphere.

Capacitors couldn't take vac, IIRC.

Cheers, Martin

Title: Re: EM Drive Developments
Post by: JPLeRouzic on 09/03/2014 07:13 AM
NASA has its own list of capacitors that includes aluminum capacitors with solid conductive polymer as the electrolyte material that are compatible with the wide range of requirements for working in space conditions.

BTW your iPhone and most modern miniaturized electronic devices use capacitors with the same technology because no bulky wet capacitor would fit the form factor.

On a completely unrelated topic, unfortunately this kind of capacitor fuels wars in central Africa.
Title: Re: EM Drive Developments
Post by: MP99 on 09/03/2014 07:36 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1250392#msg1250392">Quote from: JPLeRouzic on 09/03/2014 07:13 AM</a>
NASA has its own list of capacitors that includes aluminum capacitors with solid conductive polymer as the electrolyte material that are compatible with the wide range of requirements for working in space conditions.

BTW your iPhone and most modern miniaturized electronic devices use capacitors with the same technology because no bulky wet capacitor would fit the form factor.

On a completely unrelated topic, unfortunately this kind of capacitor fuels wars in central Africa.
Isn't this a far higher power level than iPhone?

Cheers, Martin

Title: Re: EM Drive Developments
Post by: JPLeRouzic on 09/03/2014 08:22 AM
=>It depends about what you discuss, while I agree that EmDrive uses hundreds watts, the EagleWorks device just used 17 Watts.
It is not far from the power needed by an iPhone cellular 3G emitter (max 5 Watts but the emitter is quite inefficient).
And we don't know the circuit purpose and design where a capacitor was used, so we can't make any prediction about what power this capacitor must support. This kind of capacitor (wet or solid) is not used to filter out gigahertz.
But that's not my point, it was about technology of capacitors, not about the specific value of capacitance nor the typical power it can support. iPhones as most other consumer devices use solid polymer capacitors.
Title: Re: EM Drive Developments
Post by: Stormbringer on 09/03/2014 12:02 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1250357#msg1250357">Quote from: MP99 on 09/02/2014 10:01 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1250335#msg1250335">Quote from: Star One on 09/02/2014 09:10 PM</a>
I thought it was tested in a vacuum chamber.
Yup, bat at 1 atmosphere.

Capacitors couldn't take vac, IIRC.

Cheers, Martin
That is true and kind of inexplicable, really. But Dr Woodward tested his version of this thing in a vacuum. conclusion: this general class of device works in a vacuum.

Title: Re: EM Drive Developments
Post by: sghill on 09/03/2014 12:49 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1250337#msg1250337">Quote from: QuantumG on 09/02/2014 09:13 PM</a>
Radiometers do work in a vacuum, just not particularly well.

That's not the point here.  The point is that the "drive" may have inadvertently worked like a Crookes radiometer heat engine.  A Crookes radiometer stops working in a full vacuum because there are no air molecules for the radiant energy absorbed on black side of the radiometer to excite, and the friction of the spinner can't be overcome by the light pressure on the silvered side.  It works best in a partial vacuum (read the wiki article) and it also works backwards compared to what you'd expect from a light pressure powered solar sail.

In the case of the EMDrive test articles, if the microwaves created uneven heating of the interior surfaces at normal air pressure, those surfaces could have warmed the air molecules and created the thrust detected by the very sensitive torsion balance. 

If this was indeed the case, then if they repeat the experiment in a full vacuum, the thrust effect will go away.  If it doesn't go away, then perhaps they are on to something.

Title: Re: EM Drive Developments
Post by: JasonAW3 on 09/03/2014 01:49 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1250405#msg1250405">Quote from: MP99 on 09/03/2014 07:36 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1250392#msg1250392">Quote from: JPLeRouzic on 09/03/2014 07:13 AM</a>
NASA has its own list of capacitors that includes aluminum capacitors with solid conductive polymer as the electrolyte material that are compatible with the wide range of requirements for working in space conditions.

BTW your iPhone and most modern miniaturized electronic devices use capacitors with the same technology because no bulky wet capacitor would fit the form factor.

On a completely unrelated topic, unfortunately this kind of capacitor fuels wars in central Africa.
Isn't this a far higher power level than iPhone?

Cheers, Martin

Wile I was in the NAVY, I saw solid capaciter units hooked up to the radar systems that would make you plotz!  These things were MONSTERS!

      I suddenly understood why we would sometimes find partially cooked dead birds up on the Radar antenna level on board ship.  And THIS was beck in the 1980's!

Title: Re: EM Drive Developments
Post by: Rodal on 09/07/2014 07:06 PM
I have concluded that thermal transient effects are a likely explanation for the measured deflections and forces in NASA's torsion pendulum experiments of the Q drives.  Explicitly, that they are the result of a shift in material location of the center of mass due to differential thermal expansion resulting from heating of the dielectric resonator which is positioned unsymmetrically.  If this explanation is correct, Dr. White still should also be able to measure (slightly lower) forces when he places the Q drive in a torsion pendulum in a vacuum.  However, if the Q drive were free in space (instead of supported from a pendulum), this transient, unsymmetric, thermal expansion would result only in a change in attitude (orientation).

I am posting here my letter to Dr. White in order to have a wider review of this explanation. 

Dear Dr. White,

I have read with appreciable interest your paper (co-authored with D. Brady, P. March, J. Lawrence, and F. Davies) titled "Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum", presented at the 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, July 28-30, 2014 in Cleveland, OH.

I have thought about what may be responsible for the measured displacement (and force) in your reported torsion pendulum experiments.  Air convection resulting from microwave heating of the air surrounding the Q-drives has been suggested by various people, as the air speed that can produce the measured force can be shown to be small.  You will be able to check whether air convection is responsible when you perform experiments in a vacuum (which I understand from your report was not possible because of the aluminum electrolytic capacitors that need to be replaced by capacitors that can work in a vacuum environment).

However, I have wondered how air convection could be responsible for the reproducible and fairly consistent levels of measured force pulse, as well as the fact that the experimental pulses are so well defined (and that it took practically no time to achieve the measured forces and to go back to zero upon ending the microwave pulse), and that turning the Q-drive around by 180 degrees resulted in practically the same force in the opposite direction.

Based on my experience conducting experiments at the Massachusetts Institute of Technology Aeronautics and Astronautics Department (for my S.B., S.M. and Ph.D. degrees at MIT) and later on at industrial R&D laboratories, I have arrived at the conclusion that transient thermal effects in your experiments should be carefully considered.

Indeed, after much thought and some calculations my conclusion is that the measured forces can quite likely be the result of transient thermal effects that very slightly shift the location of the center of mass in the material body of the Q-drive, due to unsymmetric thermal expansion, resulting from internal heating of the dielectric resonator in the Q-drive.

The center of mass changes location in the material body, with respect to body-fixed, Lagrangian coordinates, as it expands unsymmetrically.  If the body would be free (unrestrained) in space, this would result only in a change in attitude (orientation) of the body. If free in space, the spatial position of the center of mass will not change (with respect to an inertial frame of reference).  However, because the tested Q-drives were restrained, suspended from a support point in a torsion pendulum, the unsymmetric thermal expansion will generate a small measurable rotation and (torquing) force because the center of mass changes location in the material body as it expands unsymmetrically. 


Similar issues (thermal distortion resulting in changes in orientation) were experienced, for example in spacecraft, most prominently with the Messenger (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft that got closer to the Sun:  See:  http://messenger.jhuapl.edu/the_mission/publications/O'Shaughnessy_Pittelkau.2007.pdf

Interestingly, your paper points out the importance of the (Teflon) dielectric resonator concerning the experimentally measured forces:

<<The longer beam pipe is the RF drive antenna that in practice ends up being a ¼ wave resonance system in its own right and has a dielectric PTFE slug in the throat in both the slotted and null test article. It is this characteristic that became an item of further consideration after completion of the test campaign.>> (p.7)

<<There appears to be a clear dependency between thrust magnitude and the presence of some sort of dielectric RF resonator in the thrust chamber.>> (p.18)

<<We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust.>>( p.18)

It is noteworthy that the test conducted without the dielectric resonator resulted in no significant measurable force. 

My analysis of the reaction force that results from the greater thermal expansion of the drive adjacent  to the dielectric resonator shows that the reaction force should be in the direction towards the end that has no  dielectric resonator.  That is, if the dielectric resonator is to the right of the center of mass of the drive, the reaction force will be to the left,  and if the drive is positioned such that the dielectric resonator is located to the left of the center of mass of the drive, the reaction force will be to the right.  This agrees with all your experimental results.

My analysis of the reaction force that results from the greater thermal expansion of the drive adjacent  to the dielectric resonator also shows that if the drive were perfectly symmetric (for example having the dielectric resonator centered at the center of mass, or having identical dielectric resonators located at the same distance from the center in both directions), there would be no net thermal distortion forces as they would balance themselves out.  In other words, if the Q-drive would have the dielectric resonator in the middle, or have two identical dielectric resonators positioned at equal distances from the center of mass, there would be no measurable forces.

Heat is generated inside the dielectric resonator due to the dielectric loss ("tan delta") material property of the resonator.  This internal heat power is produced instantly as a result of the electromagnetic field but it takes a finite amount of time for the temperature to diffuse through the material and reach steady state in accordance with Fourier's equation of heat conduction, depending on the diffusivity of the material, and satisfying  the thermal boundary conditions (convection and radiation if the experiment takes place in air, and just radiation if it takes place in a vacuum).  Since the dielectric loss factor ("tan delta") is temperature dependent, the heat generated is also temperature-dependent, which introduces a nonlinearity in the solution of the differential equations for this problem.  As the polymer ("Teflon" PTFE thermoplastic Fluoropolymer) dielectric temperature rises, it expands both in its radial and longitudinal direction.  There is also a dynamic effect due to the inertial forces reacting to the sudden pulse, in addition to the torsional resisting force of the torsional pendulum.

The thermal expansion of the polymer dielectric resonator in the radial direction results in better contact and heat transmission to the copper structure of the drive.  It can be readily shown that the effect of air convection in this experiment should be small in comparison with thermal conduction.

The reaction force produced by unsymmetric thermal expansion is proportional to the second derivative of temperature with respect to time. 

To calculate how long it takes for the temperature distribution to reach steady state (and therefore for the second derivative of temperature with respect to time to become negligibly small) we may use the Fourier Number: the thermal diffusivity times the characteristic time divided by the square of the characteristic length.  It is known that steady state is typically reached for a Fourier number exceeding unity, that is, for the characteristic time exceeding the ratio of the square of the characteristic length divided by the thermal diffusivity.  The thermal diffusivity of Teflon is 0.124 (mm^2)/sec.   I could not find the dimensions of the Teflon dielectric resonator in the report.  I calculate that the time to reach thermal steady state exceeds 22 minutes if the characteristic length of Teflon is 0.5 inch (12.7 mm).  If the characteristic length of Teflon is 0.2 inch (5 mm), the time to reach steady state will exceed approximately 4 minutes.  If the characteristic length of Teflon is 1 inch (25.4 mm), the time to reach steady state will exceed 1 hour and 27 minutes.  We know from the report that the microwave pulse was maintained for only 35 seconds during the testing (see Fig.12, p.9 in the report).  Therefore, we know that the microwave pulse was maintained for an amount of time much shorter than the amount of time necessary for the temperature distribution to reach steady state in the Teflon dielectric resonator.

When the microwave power is turned off (Fig.12, p.9 of the report shows this happening 35 sec after it was turned on), the heat generating power suddenly becomes zero, and hence the second derivative of the temperature with respect to time (responsible for the reaction force) becomes negative when the microwave power is turned off, resulting in a force in the opposite direction as to when the microwave power was on. 

Since copper's Young modulus is about 300 times stiffer than Teflon's, and assuming that the Teflon, particularly as it expands radially, is in frictional contact with the surrounding copper, it makes sense to assume that the expansion of the Teflon dielectric resonator is restrained by the much stiffer copper.  Under that assumption, we can calculate the differential thermal expansion of the copper surrounding the Teflon as the product of the coefficient of thermal expansion of copper (16.6*10^(−6) 1/degC) times the longitudinal length of the Teflon resonator, times the "delta T": the temperature difference between the copper surrounding the Teflon and the rest of the structure. 

If the longitudinal length of the Teflon resonator is 1 inch (25.4 mm), the delta T necessary to produce a differential thermal expansion of 4 micrometers is only 9.5 deg C (17 deg F).  So it is quite possible to produce the measured deflections with a delta T in temperature of a few deg C.  If the Teflon is unrestrained by the copper, the required  delta T is 8 times smaller (since the coefficient of thermal expansion of Teflon is 135* 10^(−6) 1/degC, eight times greater than the coefficient of thermal expansion of copper).

I hope that these considerations, convince you (as has been my experience in testing at MIT and in industrial R&D) that thermal transient effects are important and therefore that it merits strong consideration that the measured deflections and forces in your torsion pendulum experiments of the Q drives are the result of a shift in material location of the center of mass due to differential thermal expansion resulting from heating of the dielectric resonator which is positioned unsymmetrically, as explained above.

Best regards,

Dr. Jose' J. Rodal
jrodal@alum.mit.edu
Title: Re: EM Drive Developments
Post by: IslandPlaya on 09/08/2014 08:45 AM
Great post!
Welcome to the forum.
Title: Re: EM Drive Developments
Post by: Star One on 09/08/2014 03:42 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1252569#msg1252569">Quote from: IslandPlaya on 09/08/2014 08:45 AM</a>
Great post!
Welcome to the forum.

Be interesting to hear about the response as I imagine that is just one amongst many, many pieces of correspondence that have no doubt been fired in his direction since the announcement.

Title: Re: EM Drive Developments
Post by: aceshigh on 09/08/2014 05:59 PM
insteresting...

considering NSF user Stardrive (Paul March) works with Dr. Sonny White at Eagleworks Lab, specifically at the Q-Thrusters experiments (though if I am not mistaken he attributes the effects to Woodward Effect), I wonder if there would be any chance of him answering that.
Title: Re: EM Drive Developments
Post by: sghill on 09/08/2014 11:39 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1252724#msg1252724">Quote from: aceshigh on 09/08/2014 05:59 PM</a>
insteresting...

considering NSF user Stardrive (Paul March) works with Dr. Sonny White at Eagleworks Lab, specifically at the Q-Thrusters experiments (though if I am not mistaken he attributes the effects to Woodward Effect), I wonder if there would be any chance of him answering that.

Well, I think Dr. Jose was mixing up EMDRIVE with Qthruster, but otherwise, let's hope for a response.

Title: Re: EM Drive Developments
Post by: Rodal on 09/09/2014 12:12 AM
The authors (Brady, White, et.al.) of the paper ("Anomalous Thrust..."July 28-30, 2014, Cleveland, OH; AIAA/ASME/SAE/ASEE Joint Propulsion Conference) referred to ALL the tested thrusters, in general as  "potentially interacting with the quantum vacuum" in their abstract:

<<Test campaign results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma>> (Abstract)

or "potentially a Q-thruster":

<<... the RF launcher tube assembly with dielectric cylinder common to both the [Cannae] slotted and smooth test articles is potentially a Q-thruster where the pillbox is simply a matching network>> (p.10)

<<Tapered Cavity RF Evaluation, General Findings and Lessons Learned...We discovered early in the COMSOL® analysis process that just because you can achieve a great RF solution does not mean that it will be an ideal Q-thruster implementation.>> (p.18)

<<The near term objective is to complete a Q-thruster breadboard test article that is capable of being shipped to other locations which possess the ability to measure low thrust for independent verification and validation (IV&V) of the technology>> (p.21)

<<D. A. Brady... thanks Kent Joosten for his substantial contribution to Q-thruster mission analysis>> (p.21)

So, I intentionally adopted the author's general description of "Q-thruster" for all the devices tested by the authors  in their paper, because the different explanation I offer above (transient thermal unsymmetric expansion) for their experimental measurements applies equally well to all the different types of devices (both the Cannae-type and the Tapered Cavity ) tested by the authors.
Title: Re: EM Drive Developments
Post by: Rodal on 09/09/2014 12:52 AM
Furthermore, Dr. White himself has repeatedly used the general word "Q-thruster" in the past to refer to ALL of the electromagnetic devices he has tested (including the EM Drive).   

For example see slide 40 of his presentation "WARP FIELD PHYSICS" (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf ) where he shows photographs for six different test campaigns for different devices (including the Boeing, Lockheed-Martin, EM Drive, Cannae, and two others) ALL under the same title of "Q-thruster Physics Data"
Title: Re: EM Drive Developments
Post by: Slyver on 09/09/2014 09:28 AM
@Rodal

Can you provide the calculations you used for your analysis?

I attempted to do a quick model of the system with your ideas.  Using a few assumptions:

-- 25mm diameter x 5mm height cylindrical dielectric
-- 150mm length cavity
-- 5 degrees increase in temperature
-- Thermal expansion of the dielectric peaked instantly

I got a tangential torque of -5.6 x 10^-7 NM.  This is in the opposite direction, and two orders of magnitude less than the net force on the system.

The dielectric, assuming it was fastened to the top of the cavity (i.e. the face in the direction of the thrust) expands in the opposite direction (outward from the face) and thus changes the center of gravity of the system in the same direction as the expansion (and opposite of the measured thrust).

I did not run an analysis of the rate of thermal expansion of the dielectric, but you seem to have its net thermal expansion at the measured thrust (i.e. after 1s) ~ the same as its steady state expansion at the increased temp, and yet you state in your email only how long it takes to reach steady state.  The measurements in the data show both a very sharp increase in thrust (~1s from 0 to peak) and peak equal to initial thrust, suggesting by your model that there is no increase in thermal expansion between 1s and steady state (minutes).

I am only asking for detailed explanations (in both math and words preferably), not saying you are incorrect.  It is entirely possible I made mistakes in both my assumptions and my quick math.
Title: Re: EM Drive Developments
Post by: aceshigh on 09/09/2014 02:38 PM

Rodal, I posted your question at Talk Polywell Forum, where Paul March (who works at Eagleworks Lab with Dr Sonny White, at the Q-Thrusters, and I guess also took part in the investigation of the EMDrive) sometimes reads stuff.


Here is his answer:

Quote
AcesHigh:

You can inform Dr. Rodal that most of the observed forces in the Eagleworks Lab frustum devices were prompt with the same rise and fall times as our electrostatically derived calibration forces and therefore are not thermal in origins. That's not to say we didn't see thermal effects, especially with input RF power levels greater than ~35W, but the thermal effects with these large copper plus dielectric test articles, (2.5 to 5.0kg), always take tens of seconds to develop and are easily distinguished from the prompt E&M or more interesting force inputs since they always exhibit exponential rise and fall times.

BTW, the copper frustum's temperature never rose more than 1.0 degree F. when using the above average power levels and test articles.

Best,
Paul March


Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/09/2014 02:46 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1252386#msg1252386">Quote from: Rodal on 09/07/2014 07:06 PM</a>
I have concluded that thermal transient effects are a likely explanation for the measured deflections and forces in NASA's torsion pendulum experiments of the Q drives.  Explicitly, that they are the result of a shift in material location of the center of mass due to differential thermal expansion resulting from heating of the dielectric resonator which is positioned unsymmetrically. ...

I hope that these considerations, convince you ... that thermal transient effects are important and therefore that it merits strong consideration that the measured deflections and forces in your torsion pendulum experiments of the Q drives are the result of a shift in material location of the center of mass due to differential thermal expansion resulting from heating of the dielectric resonator which is positioned unsymmetrically, as explained above.

Thank you very much for the quite readable analysis.

1.  Could you provide your calculations, following the order of your correspondence, perhaps tagging the calcs to the paragraphs?

2. It seems clear that vacuum testing of the device would be necessary.  Could you describe or sketch a possible experimental mechanism which would more closely simulate an unrestrained body?

3. Is the torsion pendulum the only way to test a device of this sort on Earth?

4.  How crucial is the dimension of the Teflon resonator to your argument?

Title: Re: EM Drive Developments
Post by: aceshigh on 09/09/2014 03:05 PM
@John Fornaro: I just posted an answer by Paul March, who works with Dr Sonny White, regarding Radal's questions.


--------------------------------

kinda off-topic, but is Dr Rodal's first name (José) of portuguese or spanish origin? It changes the way the J is pronounced (if portuguese, it´s similar to english J in Joseph, not the SAME sound, but closer to it than to Spanish J)
Title: Re: EM Drive Developments
Post by: sghill on 09/09/2014 03:19 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253094#msg1253094">Quote from: aceshigh on 09/09/2014 03:05 PM</a>
@John Fornaro: I just posted an answer by Paul March, who works with Dr Sonny White, regarding Radal's questions.

Irrespective of the science, what an awesome use of this forum- and thread!  Thanks to Aces, and John, and Dr. Jose, and Paul for all your contributions!!

How exciting. :)

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/09/2014 04:13 PM

Quote from: rodal
However, I have wondered how air convection could be responsible for the reproducible and fairly consistent levels of measured force pulse, as well as the fact that the experimental pulses are so well defined (and that it took practically no time to achieve the measured forces and to go back to zero upon ending the microwave pulse), and that turning the Q-drive around by 180 degrees resulted in practically the same force in the opposite direction.

Quote from: March
You can inform Dr. Rodal that most of the observed forces in the Eagleworks Lab frustum devices were prompt with the same rise and fall times as our electrostatically derived calibration forces and therefore are not thermal in origins.

Rodal has noticed the "prompt" and "well defined" rise and fall times of the measured forces; that part at least, has not been overlooked, nor answered.  Rodal goes on to discuss the rather long times for the Teflon to achieve a thermal steady state, but what Rodal doesn't do is offer his suggestion as to the speed and dimension of the "reaction force" caused by the dielectric resonator, and how it relates to the prompt and well defined rise and fall times of the measured forces.

That's why I asked about the dimensions of the Teflon. 

In order for the device to operate for several days (as if it were flying to the Moon) it would have to be operated rather continuously, and there would be some kind of steady state operation that would have to be engineered.  But that would be a future game.

Title: Re: EM Drive Developments
Post by: Rodal on 09/09/2014 05:06 PM
I'm glad that I posted in this forum, great, quality feedback :D  Thanks to everyone for your comments.

I'll try to answer this evening when I have time available.


____________

@aceshigh, thank you for your initiative to pursue this with Paul March. Please thank him for his answer, which is much appreciated.  It would be great if you could pursue further answers to the following questions:

1) What was the length (between upper support and lower fixture point) of the pendulum ?

2) What was the total weight suspended on the pendulum ?

3) What were the different shapes (cylindrical, disc, etc. ?) and the dimensions of the Teflon dielectric resonators that were used in the experiments?

4) What were (all) the surface Boundary Conditions of the Teflon dielectric resonators ? how were the dielectric resonators put in position?

___________
@aceshigh: answering your off topic question, my first name is a geographic accident of being born in a country where (at that time) there was a law that everyone born there had to be given names chosen from a Government-provided list.  .  The "J" is pronounced as an "H":D
Title: Re: EM Drive Developments
Post by: aceshigh on 09/09/2014 05:33 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253159#msg1253159">Quote from: Rodal on 09/09/2014 05:06 PM</a>
@aceshigh: answering your off topic question, my first name is a geographic accident of being born in a country where (at that time) there was a law that everyone born there had to be given names chosen from a Government-provided list.  .  The "J" is pronounced as an "H":D

if it´s pronounced as an english H, then I guess it´s of spanish origin. I asked because I am brazilian, and as a portuguese speaker, I have the tendency to read José with the portuguese J.

(google translate pronounciation button is very good for these matters, if you are curious)

I will forward your questions to Paul March. I am not sure he can answer all of them. I remember reading a couple of years ago that he had signed a non-disclosure contract with NASA or maybe with Dr White, which was when he stopped being active both here at Nasa Spaceflight Forum and TalkPolywell forum... he used to post LOTS of info about his workings with Dr James Woodward at Mach Effect and such.

Title: Re: EM Drive Developments
Post by: Rodal on 09/09/2014 07:38 PM
My understanding is that White et.al. used an inverted torsion pendulum for their experiments.  If there are Non Disclosure Agreements, they must deal with the inner workings of proprietary drives that were tested, but I imagine that the inverted torsion pendulum should NOT be part of these NDA's.  Since White et.al. published their experimental results performed at NASA, I would imagine that a description of the experimental procedure, most importantly the pendulum geometry, should be part of their description for the scientific/engineering community to review, and this would not be covered by NDA's.

My pendulum geometry questions are then more properly framed as follows:

1) What is the length of the inverted torsion pendulum between the lower torsional support and the upper centering bearing ?

2) What is the total weight of the upper portion: the tested object, its support table,  and any other fixtures and equipment on the table?

3) What is the maximum off-center motion allowed by the centering bearing ?

4) What is the spring constant (about a rotating axis normal to the vertical arm of the pendulum) of the bottom joint that tries to keep the inverted pendulum upright in a vertical position?
Title: Re: EM Drive Developments
Post by: aceshigh on 09/09/2014 08:01 PM
it´s possible Rodal. I already forwarded your previous questions to the Talk Polywell forums, but I also asked Dr Paul March if he could answer your questions directly here, so I can stop playing messenger boy haha ;)
Title: Re: EM Drive Developments
Post by: aceshigh on 09/09/2014 08:06 PM
Mr Chang from NextBigFuture already caught on to the interesting discussion going on between Dr Rodal and Dr March and posted an update at his site:
http://nextbigfuture.com/2014/09/nasa-cannae-drive-and-emdrive.html
Title: Re: EM Drive Developments
Post by: Rodal on 09/10/2014 12:43 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253015#msg1253015">Quote from: Slyver on 09/09/2014 09:28 AM</a>
I attempted to do a quick model of the system with your ideas.  Using a few assumptions:.....
I got a tangential torque ... in the opposite direction, and two orders of magnitude less than the net force on the system.
@Slyver

First of all thank you for taking the time and initiative to do your own independent modeling.  We face at least three problems in modeling this experiment: 1) the NASA paper does not describe the experiment with enough detail that we can model it without making a number of assumptions (hopefully we will get some more details in the future), 2) the experimental set-up is not trivial (for example: the inverted pendulum) and 3) the measured force is extremely small so a number of normally negligible effects can be responsible.   By working independently yet asking questions about our models perhaps we can eliminate some possibilities, correct our models and narrow down the possible explanations.

So let me start with the force that I did not explicitly mention in my write-up nor it appears in yours: gravity.  Did you model the inverted torsion pendulum?

- I am multi-tasking  - running some programs while I'm writing this, so I will do this in short segments.  The next one to follow discussing my inverted pendulum  modeling

Title: Re: EM Drive Developments
Post by: Rodal on 09/10/2014 12:56 AM
@Slyver  (CONTINUED)

The motion of the inverted torsional pendulum is, in general. the combination of 3 types of oscillation: 1) Torsional,
2) Swinging and 3) Bouncing.  I neglected the (vertical) bouncing oscillation under the assumption that the pendulum's vertical arm (some people call it "leg") is stiff enough (in relation to the supported mass) so that the longitudinal "bouncing" vibration displacements are negligible (of course, we would need to double check this assumption once we know the supported mass and the arm's dimensions and material construction).
Title: Re: EM Drive Developments
Post by: Rodal on 09/10/2014 01:10 AM
@Slyver  (CONTINUED)

I modeled the swinging oscillation of the inverted pendulum with a natural (angular) frequency

omega= Sqrt[(k/M)-(g/l)]

where:

k= spring constant (about a rotating axis normal to the vertical arm of the pendulum) of the bottom joint that tries to keep the inverted pendulum upright in a vertical position

M=total supported mass ( total weight of the upper portion: the tested object, its support table,  and any other fixtures and equipment on the table)

g=acceleration of gravity

l=length of inverted pendulum's arm between the lower torsional support and the supported mass

Title: Re: EM Drive Developments
Post by: Rodal on 09/10/2014 01:19 AM
@Slyver  (CONTINUED)

In the above formula, I neglected the mass of the pendulum's arm "mArm".  If this mass is not negligible, then the angular frequency of swinging oscillation would be:

omega= Sqrt[(k-(g/l) ( M+(mArm/2) ) )  /   ( M+(mArm/3) )]

where:

k= spring constant (about a rotating axis normal to the vertical arm of the pendulum) of the bottom joint that tries to keep the inverted pendulum upright in a vertical position

mArm=mass of the pendulum's arm

M=total supported mass ( total weight of the upper portion: the tested object, its support table,  and any other fixtures and equipment on the table)

g=acceleration of gravity

l=length of inverted pendulum's arm between the lower torsional support and the supported mass
Title: Re: EM Drive Developments
Post by: Rodal on 09/10/2014 01:31 AM
@Slyver  (CONTINUED)

If the supported mass is small enough, then omega ( the angular frequency of swinging oscillation ) is a real positive number and the pendulum may exhibit a harmonic swinging motion (hopefully of very small amplitude).  If the supported mass is too large, omega is an imaginary number (or in other words, the expression inside the square root becomes negative) then the pendulum will collapse, falling over over towards one side against the centering bearing.
Title: Re: EM Drive Developments
Post by: Rodal on 09/10/2014 01:44 AM
@Slyver  (CONTINUED)

The swinging pendulum motion is, in principle, around two orthogonal swinging directions.

___________
There are other possible frequencies of swinging oscillation which I did NOT model.  For example if the pendulum arm bends at the upper end, one would also expect a composite pendulum with another frequency. 

I mention this because the NASA authors mention:

<<If needed, ballast is added to the pendulum arm to eliminate moments that affect the neutral position of the pendulum arm.>> (p.5)

In any case it is interesting that they are conscious that their experimental inverted pendulum set-up is capable of having moments affecting the neutral position of the pendulum arm (even if it doesn't bend).  The authors took care of using ballast to eliminate these moments at start-up (however, we have to calculate whether such moments affecting the neutral position of the pendulum arm are significant due to unsymmetric thermal expansion).  It is evident that "k/M" is not infinite !. The bearings allow some off-center motion. Their inverted pendulum is capable (as all inverted pendulums are) of swinging oscillations.
Title: Re: EM Drive Developments
Post by: Rodal on 09/10/2014 02:56 AM
@Slyver  (CONTINUED)

So (neglecting the mass "mArm" of the arm) , for the swinging motion of the inverted pendulum, we have two forces acting along the swinging arc, in opposite directions:

1) Due to gravity: the force component tangent to the swinging arc,
Fg = - M g theta ~ - M g x / l ,
which is de-stabilizing: it has the opposite sign to the force of gravity in the simple pendulum

and

2) Due to the elastic spring "k" (about a rotating axis normal to the vertical arm of the pendulum)  that tries to keep the inverted pendulum upright in a vertical position,
Fk = + k l theta ~ + k x

where the swinging angle can be approximated as

theta ~ x / l 

where "x" is the horizontal displacement and "l" is the length of the inverted pendulum's arm between the lower  support and the upper supported mass

For the inverted pendulum to work as designed, the elastic spring force (that tries to keep the inverted pendulum upright in a vertical position) must be greater that the de-stabilizing force of gravity, otherwise, as already discussed the pendulum will collapse towards one side:

Fk  > Fg

or

 k l  > M g

or

( (k / M) - (g / l ) ) > 0

Title: Re: EM Drive Developments
Post by: Rodal on 09/10/2014 03:09 AM
I'll continue this tomorrow...  as well as answering the other questions, from John Fornaro and others
Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/10/2014 12:26 PM
Just for grins, here is a random linear actuator which gets 4N of "peak force" for 28 watts.
Title: Re: EM Drive Developments
Post by: Star-Drive on 09/10/2014 12:42 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253229#msg1253229">Quote from: aceshigh on 09/09/2014 08:01 PM</a>
it´s possible Rodal. I already forwarded your previous questions to the Talk Polywell forums, but I also asked Dr Paul March if he could answer your questions directly here, so I can stop playing messenger boy haha ;)

AcesHigh and Dr. Rodal:

Interesting thread, but you would have saved yourselves a lot of wasted effort if you had first obtained the needed details before going so far down this analysis rabbit trail.  That said, yes I'm covered by a number of NDA's that do not allow me to talk about third party test articles.  However since Dr. White has already published several papers on the Eagleworks Lab home-grown torque pendulum thrust measurement system and frustum cavity test articles, I think I can comment at least on those topics when my time permits.

Now in regards to the Eagleworks Lab's torque pendulum, it is a conventional horizontal torque pendulum with two C-flex torsional bearing blocks with one bearing block mounted directly above the torque pendulum arm and the other below it on the same rotational axis.  From memory the distance between the bearing blocks to the torque pendulum arm is around 4.0", but I'll re-measure it today to make sure.  The length of the aluminum pendulum arm is 24.00 inches with the center of rotation being offset from its center of mass by about 4.0" before adding additional masses, but again I'll re-measure it today to get its current dimensions.  The Riverhawk C-flex torsion bearing's spring constant is a nominal 0.007 in-Lb/deg., but that varies with the mass load mounted on the torque pendulum arm and selected balance point of the test article mass and its counterbalance mass on the other end of the pendulum arm relative to the torque pendulum’s center of rotation.  Each bearing block is rated for ~25.0 Lb of vertical mass load, so we nominally restrict ourselves to a 25 pound total load limit on the torque pendulum arm to give ourselves a 100% support mass margin.

More later for I now have to get to work...

Title: Re: EM Drive Developments
Post by: Rodal on 09/10/2014 10:13 PM
@Paul March,

What are the units of the Electric Field (shown ranging from 0 to 3000) in Fig. 14 ?

titled "Cross section of test article (left) and close up of fields in RF drive pipe (right)", from the <<Computer modeling of the electric field within the pillbox and beam pipe (using COMSOL Multiphysics® software>> 

on page 10 of your paper (with Brady, White, et.al.)

"Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum" July 28-30, 2014, Cleveland, OH,  50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference
Title: Re: EM Drive Developments
Post by: Star-Drive on 09/10/2014 11:32 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253719#msg1253719">Quote from: Rodal on 09/10/2014 10:13 PM</a>
@Paul March,

What are the units of the Electric Field (shown ranging from 0 to 3000) in Fig. 14 ?

titled "Cross section of test article (left) and close up of fields in RF drive pipe (right)", from the <<Computer modeling of the electric field within the pillbox and beam pipe (using COMSOL Multiphysics® software>> 

on page 10 of your paper (with Brady, White, et.al.)

"Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum" July 28-30, 2014, Cleveland, OH,  50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference


The units for all the E-field measurements in our 2014 JPC paper is volts per meter (V/m).

As to the torque pendulum dimensions, the center of the two C-flex bearing blocks is 2.38" above and below the centerline of the 24.00" long by 1.50" square aluminum pendulum arm.  The long end of the pendulum arm is 15.5" from the torque pendulum's center of rotation, which makes the other short-end of the pendulum arm 8.5" from the center of rotation.  And all the pendulum's aluminum structural elements are electrically bonded together and then grounded to the vacuum chamber's 304 alloy stainless steel walls that is in turn grounded to the facility's green wire safety ground system.  This grounding arrangement's function is to preclude the buildup of electrical patch charges on the various parts of the pendulum and vacuum chamber during operations.

BTW, the reason we didn't test in vacuum for these test series was that our 35W RF amplifier, that was mounted on the torque pendulum arm as the counterbalance mass for the test articles, was that it's electrolytic capacitors would pop at the low pressures, thus disabling it.  We have since obtained two ~100W RF amplifiers that are hermetically sealed that will allow us to test down to ~5x10^-6 Torr vacuum pressures in the near future, at least once we sort out our current phase locked loop design issues.

Best,

Title: Re: EM Drive Developments
Post by: Rodal on 09/11/2014 12:50 AM
@Paul March,

An elegant way to show that the experimentally measured pulse is NOT due to thermal effects is to make the following calculations based on the electric field shown in Fig. 14, titled "quot;Cross section of test article (left) and close up of fields in RF drive pipe (right)", from the <<Computer modeling of the electric field within the pillbox and beam pipe (using COMSOL Multiphysics® software>>  of page 10 of your 2014 JPC paper co-authored with Brady, White, et.al. and to compute the maximum dissipated power as follows:

DissipatedPower = 2 Pi f (E^2) (permittivity of free space) (epsilon')(tan delta)

Taking the maximum value of the Electric Field shown in Fig. 14, p.10, as 4.7189*10^4 V/m , and the given frequency of 935 MHz, it immediately follows (for the Teflon PTFE dielectric resonator) that:


DissipatedPower [W/m^3] = 2 Pi (935*10^6 1/s) (( 4.7189*10^4)^2) (8.85418782*10^(-12)) (2.1)(0.0003)

DissipatedPower =  72973  W/m^3 = 0.0729 W/cm^3

and then use this value to compute the temperature rise in Teflon (without any heat losses):

dT/dt = DissipatedPower / (HeatCapacity*Density)


dT/dt = ( 0.0729 W/cm^3 ) /( (1.3 J/(g deg C)) (2.22 g /cm^3 ))

dT/dt = 0.0253 deg C /s = 1.517 deg C /min

or in deg F:

dT/dt = 0.0455 deg F /s = 2.731 deg F /min



(Fron Fig. 12), the measured pulse's temperature rise takes about 4 seconds, during which time the maximum possible temperature reached is only 0.18 deg F.

Also, at the end of the whole 35 seconds pulse, the maximum possible temperature reached is just 1.59 deg F


Jose' Rodal

Title: Re: EM Drive Developments
Post by: Rodal on 09/11/2014 01:04 AM
Also, since the coefficient of thermal expansion of Teflon PTFE is 135* 10^(−6) 1/degC,

and the maximum possible temperature rise is  dT/dt = 0.0253 deg C /s

during the 4 seconds rise, the maximum possible thermal strain expansion of the Teflon PTFE resonator is:


UnrestrainedThermalStrain = 4 s *( 0.0253 deg C /s ) * ( 135* 10^(−6) 1/degC ) = 0.00137 %

which is extremely small.  For example, if the Teflon dielectric resonator is 1 inch (25.4mm) long, the maximum possible (unrestrained) change in length during the 4 sec pulse rise is only: 0.347 micrometers.

Jose' Rodal

Title: Re: EM Drive Developments
Post by: Rodal on 09/11/2014 02:00 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253771#msg1253771">Quote from: Star-Drive on 09/10/2014 11:32 PM</a>
..the 24.00" long by 1.50" square aluminum pendulum arm...

Thanks Paul for all this information.  I am thinking of another explanation, and I have these further questions:

1) Several places in your report discuss the Magnetic Damper System:

<<Figure 3. Electrostatic Fins Calibration System and Magnetic Damper>> (p.4)

<<Whenever a force is induced upon the pendulum arm, the resultant harmonic motion must be damped. This is accomplished via the use of a magnetic dampening system (MDS) at the back of the test rig. Three Neodymium (NdFeB Grade N42) block magnets interact with the pendulum’s aluminum angle to dampen oscillatory motion.>> (p.4)

<<This current causes the power cable to generate a magnetic field that interacts with the torsion pendulum magnetic damper system>> (p.14)

<<Figure 20. Null Test on Torsion Pendulum – average null force is 9.6 micronewtons due to 5.6A DC current in power cable (routes power from liquid metal contacts to RF amplifier; interacts with magnetic damper system)>> (p.16)

QUESTIONS: 

A) Was the magnetic damper on at all times in the shown traces (for the calibration pulses as well as for the thrust pulses both to the left and right ?

B) What is the nature of the interaction << ....with magnetic damper system)>>  discussed in Fig. 20 (p.16) ?

C) Are you able to apply different levels of magnetic damping (and if so have you tested them, with what results) or all you are able to do is to have this level of magnetic damping either on or off ?

D) There is a range of thrust values that were measured for the same nominal conditions.  Were changes in the total supported mass and location of this mass made, and if so do they have any correlation with the range of thrust measured?

2) Do you know the cross-section of the 1.50" square aluminum pendulum arm ? (Is it solid, or if it is a channel, what are its internal dimensions?)

Jose' Rodal

Title: Re: EM Drive Developments
Post by: frobnicat on 09/11/2014 09:14 AM
If the measured thrust pulse were due to displacement of a mass m relative to the fixation point of the device on the arm, a constant thrust (during the pulse) implies a constant acceleration of this mass (again, relative to the mobile arm) a=F/m, and an integrated displacement at the end of the pulse x = 1/2at² = 1/2 F/m t² = 0.064/m  (approx. with F=80µN and t=40s, and mass m given in kg). After this phase at constant acceleration, the displacement of mass would have to continue at constant velocity for some more time to mimic a sharp fall in thrust but not an opposite thrust pulse (has would be the case if displacing mass suddenly stopped from its integrated vt at velocity). So 0.064/m is a minimum displacement, and it's 6.4 cm assuming something 1kg is moving, or 6.4mm for 10kg. Even if a thermally expanding part of the device were driving a more massive part (not needing heating the whole mass to move it), the required displacement seems much too huge for a thermal expansion, given the scales and max temperatures overall.

Nice to have some first hand feedback on this thread.

Maybe I missed that but anyone inquired or commented on the apparently systematic slope changes (downward) after the relatively clean square thrust periods ? Is there a higher period (>200s) harmonic mode in the system that gives those overall slopes on the order of 1µN/s, or is this just long period "random drifts" due to sensitivity of system ? The charts show the signals measured relative to this slowly drifting baseline (drawn as dotted yellow curve, like piecewise linear best fits). The statistically small sample makes hypothesis risky, but visually there appear a systematic downward change of slope after thruster's pulses, and (also not quite clearly) no slope changes after the (arguably smaller magnitude) 30 µN calibration periods. What is the relevance or irrelevance of this drifting baseline ?

edit : I meant "has would be the case if displacing mass suddenly stopped from its integrated at velocity"
Title: Re: EM Drive Developments
Post by: Star-Drive on 09/11/2014 12:39 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253817#msg1253817">Quote from: Rodal on 09/11/2014 02:00 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253771#msg1253771">Quote from: Star-Drive on 09/10/2014 11:32 PM</a>
..the 24.00" long by 1.50" square aluminum pendulum arm...

Thanks Paul for all this information.  I am thinking of another explanation, and I have these further questions:

1) Several places in your report discuss the Magnetic Damper System:

<<Figure 3. Electrostatic Fins Calibration System and Magnetic Damper>> (p.4)

<<Whenever a force is induced upon the pendulum arm, the resultant harmonic motion must be damped. This is accomplished via the use of a magnetic dampening system (MDS) at the back of the test rig. Three Neodymium (NdFeB Grade N42) block magnets interact with the pendulum’s aluminum angle to dampen oscillatory motion.>> (p.4)

<<This current causes the power cable to generate a magnetic field that interacts with the torsion pendulum magnetic damper system>> (p.14)

<<Figure 20. Null Test on Torsion Pendulum – average null force is 9.6 micronewtons due to 5.6A DC current in power cable (routes power from liquid metal contacts to RF amplifier; interacts with magnetic damper system)>> (p.16)

QUESTIONS: 

A) Was the magnetic damper on at all times in the shown traces (for the calibration pulses as well as for the thrust pulses both to the left and right ?

B) What is the nature of the interaction << ....with magnetic damper system)>>  discussed in Fig. 20 (p.16) ?

C) Are you able to apply different levels of magnetic damping (and if so have you tested them, with what results) or all you are able to do is to have this level of magnetic damping either on or off ?

D) There is a range of thrust values that were measured for the same nominal conditions.  Were changes in the total supported mass and location of this mass made, and if so do they have any correlation with the range of thrust measured?

2) Do you know the cross-section of the 1.50" square aluminum pendulum arm ? (Is it solid, or if it is a channel, what are its internal dimensions?)

Jose' Rodal


Answers to Dr. Rodal's Questions:

1 A & B & C) The Eagleworks Lab's magnetic damper uses three or four permanent magnets mounted on the fixed portion of the torque pendulum with a partial steel flux return that generate a constant B-field that in turn interacts with a 1.5" wide by 0.25" thick aluminum angle that is mounted to the back side of the moving aluminum arm of the torque pendulum.  Thus the B-field generates damping eddy currents in the moving aluminum angle whenever it moves relative to the B-field.  So yes it was designed to be active at all times throughout the entire stroke of the torque pendulum.  This magnetic damper system provided less than critically damped performance requiring approx. 1.5 cycles to damp out any induced motion in the pendulum arm.  The natural oscillation period of the pendulum arm when loaded with the RF amplifier, its RF plumbing and the test article was around 4.5 seconds.

D) The mass on the torque pendulum and its orientation was held constant for a particular test series.  Of course slight changes to the placement of the test article occurred when we reversed the thrust vector of the test articles, but we tried to keep the balance approximately the same for all data runs.

 In regards to force calibration we used a set of NIST traceable, pre-calibrated meshed electrostatic fins that provided a constant attractive force between the fin pair for a given applied calibration voltage over a 25% to 75% meshed fins range.  This feature allows us to generate the same calibration force independent of the loading of the torque pendulum's C-flex torsional bearings or how much the fin set is meshed within the noted fin mesh range.  Thanks go to our previous Co-Op, Bill O'Neal, who is now at Purdue University for this design. 

2) The Fastek 6063-T6 aluminum extrusion cross section used for these tests is shown in the report or at its vendor and suppliers.

See:http://www.faztek.net/ and 
http://www.amazon.com/Faztek-15QE1515UL-Aluminum-T-Slotted-Extrusion/dp/B008MQA11C&nbsp;

Title: Re: EM Drive Developments
Post by: Rodal on 09/11/2014 04:15 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253089#msg1253089">Quote from: JohnFornaro on 09/09/2014 02:46 PM</a>
3. Is the torsion pendulum the only way to test a device of this sort on Earth?

There are several types of small thrust measurement devices.   NASA has a rich tradition, with the Micropound Extended Range Thrust Stand (MERTS) at NASA' Goddard Spacefliight Center and RCA-New Jersey-Lab (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19830026735.pdf ) (circa 1980 ?) and
Haag's plasma thrust stand at NASA's Lewis Research Center (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19960008159.pdf ) in 1995. 


Basically there are three main types of devices (and subcategories):

1) The hanging pendulum -either in torsion or swinging-.  Torsion hanging pendulums have been used for sensitive, groundbreaking experiments in physics in several labs, for example, for gravity (inverse square law) and Casimir force measurements.

2) The inverted pendulum -either in torsion or swinging-.  An inverted torsion pendulum has been used by NASA Eagleworks under Dr. White.

3) The torsional style -not to be confused with torsion pendulums ! -, which uses a counterweight on one side to counteract the weight of gravity on the other side, to keep it in a neutral position.  In the neutral position there should be a horizontal line connecting the weights (that are located to the left and to the right of the central pivot point).  Its sensitivity depends on the stiffness of the pivot and the arm lengths.

The hanging pendulum and the inverted pendulum have advantages and disadvantages when compared to each other.

STABILITY: The hanging pendulum balance is inherently stable because gravity stabilizes any swinging oscillations it may experience. The inverted pendulum on the other hand is inherently unstable since the gravitational force is such as to swing the pendulum off-center.   Therefore, the inverted pendulum needs some form of upright stabilization: mainly, the bending stiffness of the vertical arm and the magnetic damping to eliminate parasitic frequencies.   (The critical ratio is the ratio of the bending stiffness divided by the supported mass as I have shown in a previous post). Magnetic dampers are also used for hanging torsion pendulums but the inverted torsion pendulum (due to its inherent instability) has more complicated nonlinear dynamics (capable of chaotic motions with attractors).


SENSITIVITY:  The sensitivity of the hanging pendulum is hindered by the length of the arm -an important issue when trying to make measurements inside a vacuum chamber, since the balance has to fit inside it-.   The inverted pendulum can be made sensitive by matching the pivot's bending stiffness with the gravitational force, but this depends on: A) the supported mass, B) the bending stiffness of the pendulum arm (for swinging motion) and C) the length of the pendulum arm, as I have shown in a previous post.

Title: Re: EM Drive Developments
Post by: Rodal on 09/11/2014 04:20 PM
The quoted article by Brady, White, March, et.al., has an outstanding ending, that reads:

<<The current plan is to support an IV&V test campaign at the Glenn Research Center (GRC) using their low thrust torsion pendulum followed by a repeat campaign at the Jet Propulsion Laboratory (JPL) using their low thrust torsion pendulum. The Johns Hopkins University Applied Physics Laboratory has also expressed an interest in performing a Cavendish Balance style test with the IV&V shipset.>>
Title: Re: EM Drive Developments
Post by: Rodal on 09/11/2014 04:37 PM
Under Professor Manuel Martinez-Sanchez (an authority in electric propulsion) students at MIT have developed different thrust balances (usually developed for their Master Thesis).

One of these balances, built a few years ago under Professor Manuel Martinez-Sanchez, had these advantages:
 
A) the ability to produce a translation, as opposed to a rotation under thrust. (Recall that the thrust balances used by Dr. White and the ones planning to be used at Glenn, JPL and John Hopkins, actually measure a rotation rather than a translation). This was accomplished by including  flexible points of known stiffness at both the top and the bottom of the stand. The engine (whose thrust is being measured) remains horizontal as the stand tilts, keeping the thrust in a known angular direction and reducing the uncertainty in the stand's measurements.

B) The MIT inverted pendulum thrust balance includes a counterweight.  It has the effect of removing (or diminishing) the sensitivity to base vibrations by creating a statically balanced design. The counterweight also removes the gravity term from the denominator of the equation for the displacement. This is very important for nonlinear dynamics stability reasons (attractors).

However my understanding is that the sensitivity of the MIT thrust measurement balance may be insufficient for Dr. White's purposes, my recollection is that the MIT Martinez-Sanchez balances range up to dozens of milliNewtons (?) with an uncertainty of a few hundred microNewtons which is sufficient for conventional electric thrusters but it is way insufficient for Dr. White's purposes.  But anyone interested should check with MIT's Aero & Astro department as they may have newer and/or more sensitive thrust balances and my understanding of their sensitivity may be incorrect !.
Title: Re: EM Drive Developments
Post by: aceshigh on 09/11/2014 05:53 PM

at NextBigFuture, GoatGuy (a known Skeptic and quite good at demolishing a lot of nonsensical stuff with good science and calculations, but also sometimes he turns his cannons even to science done well just because he doesn´t believe it), posted some stuff

Quote
feel like I'm watching a dumbshow.

So… anyone … and I mean anyone at all … do you think that there would be a electromechanical interaction of a big honking antenna inside a big conductive metal container? Ya think? No? Why not!?

I know this is somewhat the "wrong analogy" but consider, just for a second: you have a magnet that you've attached to a string. you want to measure its torsion. You place it in a copper vacuum chamber a diameter or two larger than the magnet. You start it swinging. What's the first thing that happens?

The magnet induces substantial eddy currents in the surrounding copper enclosure. This in turn generate counteracting magnetic fields. These in turn rapidly quench the oscillation of the magnet. There's real force there. REAL. Indeed, this arrangement (inverted) is used to quench the oscillations of a beam-balance's beam. Force, without stiction.

What I see is a nice big copper horn, inside a nice big metal cylinder (the vacuum cylinder). It is supposedly a high Q device, so that the microwave field will be approximately Q • P watts in energy density. Since those watts have to "go somewhere", guess what … they fill the cylinder, which has the geometry of a particularly nice Faraday shield. The chamber is not anechoic, so, they just bounce around like mad, making nodes and antinodes.

Now you think those nodes and antinodes aren't going to interact mechanically with all that metal stuff which is the apparatus?

I bet when the thing is lofted (at GREAT NASA expense) to space, it'll fail to deliver the micronewtons that it supposedly delivers. Or, to put it differently, it'll be one of the greatest days of experimental physics if it does develop the nanonewtons, when free-floating in space.

And it will be dâmned easy to measure, too. Send it off at a few meters per second "away" before turning on power. Get a good fix on its ultra-precise transmitter (laser). Turn on power. Watch it accelerate away by observing the doppler shift in the laser (sensitive to micrometers per second per second). Turn it off. Watch the change. Turn it on, watch the change. Leave it on until the power supply quits. Measure the ΔV again. It should mathematically prove, or disprove the effect.


Quote
And PS: Whenever I see in an article the stretch of imagination being used to build missions to Deimos in 50 days, I just want to puke. Its like … I need to write a book … “Seriously Bogus Science” or something.

The science which is serious enough to with straight-face, entertain all these creative things, without being critical enough of the experimental "conditions" to detect the systematic error of reasoning contained therein. The kind of science which is serious enough to pander Mills' endless succession of tripe-papers building on prior tripe-papers, purporting to have come up with a form of hydrogen in a degenerate state, that if it could exist at all would be the most common form of the stuff, and the whole Universe would have collapsed, before it was even the size of a watermelon. Oh, darn.

It is as if simply talking, and talking, and talking some more about “Q-thrusters” is somehow making them plausible, and is arguing away the systematic errors.

Folks, it is not. You don't measure micro-earthquakes during a major one. In electrical engineering as well as quantitative statistics of measurements, its called "signal to noise ratio" and "systemic errors".

Quote
To buy a $61,000,000 per lob launch-window with SpaceX, and to lob a nice space-worthy version of the device out there, to see how it works. $61,000,000 may sound like a lot to us groundhogs, but in space sciences, this is almost a rounding error. Maybe 3 rounding errors.

Furthermore, the expense is so minor, that one might reasonably get the trip "for free" from SpaceX themselves, as they clearly need to have "live fire" tests of their Falcon Heavy rocket, upcoming.

Let's say the testbed costs about a million to make competently. With 2 parts, with nice lasers, with big batteries, and all that. The thing on the test-bed didn't look like it would have cost more than $25,000 to make. I mean, under 100 watt transmitting tubes, at low gigahertz frequencies, and a bunch of commonplace copper to hold it all together. So, the test thing will be cheap 'n' dirty.

IF the Falcon Heavy launch is successful, then hey … the science cost $1,000,000. If it fails, then build another one at 10% the price (now that the kinks are worked out), and try again. SpaceX won't be put out, they can tolerate the extra (good for them) mass of a the test-bed.

If they want to get really edgy, then incorporate a bunch of micro-satellite projects from school-kids across the land. You know, growing beans in space, and whether milk will make graham crackers turn to mush in zero G.

LOL

Title: Re: EM Drive Developments
Post by: Hanelyp on 09/11/2014 07:24 PM
I'm not quite following GoatGuy's reasoning, but there are issues that can arise from a high-Q RF system.  My own focus of concern is unbalanced forces from RF in the feed line.  Without knowing the routing of the feed line I can't evaluate these potential errors properly, but plausible case can easily produce the force levels I've seen cited.
Title: Re: EM Drive Developments
Post by: Star-Drive on 09/11/2014 08:02 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253934#msg1253934">Quote from: frobnicat on 09/11/2014 09:14 AM</a>
If the measured thrust pulse were due to displacement of a mass m relative to the fixation point of the device on the arm, a constant thrust (during the pulse) implies a constant acceleration of this mass (again, relative to the mobile arm) a=F/m, and an integrated displacement at the end of the pulse x = 1/2at² = 1/2 F/m t² = 0.064/m  (approx. with F=80µN and t=40s, and mass m given in kg). After this phase at constant acceleration, the displacement of mass would have to continue at constant velocity for some more time to mimic a sharp fall in thrust but not an opposite thrust pulse (has would be the case if displacing mass suddenly stopped from its integrated vt velocity). So 0.064/m is a minimum displacement, and it's 6.4 cm assuming something 1kg is moving, or 6.4mm for 10kg. Even if a thermally expanding part of the device were driving a more massive part (not needing heating the whole mass to move it), the required displacement seems much too huge for a thermal expansion, given the scales and max temperatures overall.

Nice to have some first hand feedback on this thread.

Maybe I missed that but anyone inquired or commented on the apparently systematic slope changes (downward) after the relatively clean square thrust periods ? Is there a higher period (>200s) harmonic mode in the system that gives those overall slopes on the order of 1µN/s, or is this just long period "random drifts" due to sensitivity of system ? The charts show the signals measured relative to this slowly drifting baseline (drawn as dotted yellow curve, like piecewise linear best fits). The statistically small sample makes hypothesis risky, but visually there appear a systematic downward change of slope after thruster's pulses, and (also not quite clearly) no slope changes after the (arguably smaller magnitude) 30 µN calibration periods. What is the relevance or irrelevance of this drifting baseline ?


We found that this slope change after the test article and RF amplifer were turned on for 10-to-20 seconds was apprently due to IR radiation from the amplifier's heatsink that is mounted on the back side of the torque penlulum on an 8" square platform was affecting the top C-flex bearing more than the lower one.  We tried aluminum shielding the top bearing assembly from the heatsink IR source and managed to reverse the metioned thermal slope in the thrust plots, but after shielding the bottom one we could reduce it but still coundn't completely get rid of this thremal drift artifact.  Currently we are just living with it.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/11/2014 08:16 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254047#msg1254047">Quote from: Rodal on 09/11/2014 04:15 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253089#msg1253089">Quote from: JohnFornaro on 09/09/2014 02:46 PM</a>
3. Is the torsion pendulum the only way to test a device of this sort on Earth?

There are several types of small thrust measurement devices. ...

Hey, thanks!  Great overview! 1, 2, & 4?

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254131#msg1254131">Quote from: sghill on 09/11/2014 07:33 PM</a>
Best to ignore Goatguy ...

Sheesh, what a diatribe.  Speaking as a Capricorn, he is an embarrasment to my sign.

Still, a pet peeve of mine regarding these not yet proven technologies is the discussion about future "expectations", based on "theoretical models", and the like.

Quote from: the Brady, White, March paper
Based on test data and theoretical model development, the expected thrust to power for initial flight applications is expected to be in the 0.4 newton per kilowatt electric (N/kWe) range, which is about seven times higher than the current state of the art Hall thruster in use on orbit today.

The following predictions of missions to Saturn and all strain credulity, because they are merely the application of numbers to an equation, and do not flesh out the many requirements needed to actually carry out one of these missions, other than the single metric of "0.4 newton per kilowatt electric (N/kWe)".

It's not acceptable to handwave such missions into a suggested plausible existance based only on "theoretical models".  It's not like the technology, if proven, has no perceived utility.

Anyhow, it is fascinating to follow the real discussion going on above.

Oh.  And I can easily lowball your sister. I'll run those ads for $5M.

Title: Re: EM Drive Developments
Post by: Star-Drive on 09/11/2014 08:25 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254123#msg1254123">Quote from: Hanelyp on 09/11/2014 07:24 PM</a>
I'm not quite following GoatGuy's reasoning, but there are issues that can arise from a high-Q RF system.  My own focus of concern is unbalanced forces from RF in the feed line.  Without knowing the routing of the feed line I can't evaluate these potential errors properly, but plausible case can easily produce the force levels I've seen cited.

Please note that the entire RF system inlcuding its voltage controlled oscillator, phased locked loop, RF amplifier, RF coupler and coaxial transmission lines are hard mounted on the moving torque pendlum arm with the test artricle as it would be in flight.  The only power lines that comes across the liquid metal contacts (LMC) are the +5.0Vdc control and +28.0Vdc and their associated ground power lines for each circuit.  The Maxwell stress forces created in the LMC pots due to these dc power currects are calculated to be in the nano-Newton range and just act to restore the LMC metal pins to the center of the LMC pots that hold the Galanstan.  In otherwords these Maxwell centering stress forces just increase the effective C-flex spring constants by less than a tenth of a percent even when drawing ten amps through the plus and minus 28Vdc bus wires.  And yes, all these power wires are twisted and and shielded throughout their runs to cancel out most of B-fields associated with the RF amplifer and control power feeds.  Even with all that though, we appeared to still have a small residual interaction between these stray power line shield B-fields interacting with the stray B-fields from the magnetic damper, so we've already upgraded the magnetic damper design to further reduce this problem.  I've attached a couple of slides with the new magnetic damper design and buildup pictures.

Title: Re: EM Drive Developments
Post by: Rodal on 09/11/2014 08:48 PM
@Star-Drive (Paul March)

Concerning

<<The current plan is to support an IV&V test campaign at the Glenn Research Center (GRC) using their low thrust torsion pendulum followed by a repeat campaign at the Jet Propulsion Laboratory (JPL) using their low thrust torsion pendulum. The Johns Hopkins University Applied Physics Laboratory has also expressed an interest in performing a Cavendish Balance style test with the IV&V shipset.>>

Of course, any and all further independent testing is great and should be greatly encouraged.  For the reasons I pointed out previously, I think that it is most crucial to test in a different type of thrust balance, and of the ones discussed above (GRC, JPL and John Hopkins) it looks like the Johns Hopkins University Applied Physics Laboratory Cavendish Balance style test would be the most different, and therefore the most interesting.

Title: Re: EM Drive Developments
Post by: frobnicat on 09/11/2014 10:56 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254143#msg1254143">Quote from: Star-Drive on 09/11/2014 08:02 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253934#msg1253934">Quote from: frobnicat on 09/11/2014 09:14 AM</a>
Maybe I missed that but anyone inquired or commented on the apparently systematic slope changes (downward) after the relatively clean square thrust periods ? Is there a higher period (>200s) harmonic mode in the system that gives those overall slopes on the order of 1µN/s, or is this just long period "random drifts" due to sensitivity of system ? The charts show the signals measured relative to this slowly drifting baseline (drawn as dotted yellow curve, like piecewise linear best fits). The statistically small sample makes hypothesis risky, but visually there appear a systematic downward change of slope after thruster's pulses, and (also not quite clearly) no slope changes after the (arguably smaller magnitude) 30 µN calibration periods. What is the relevance or irrelevance of this drifting baseline ?


We found that this slope change after the test article and RF amplifer were turned on for 10-to-20 seconds was apprently due to IR radiation from the amplifier's heatsink that is mounted on the back side of the torque penlulum on an 8" square platform was affecting the top C-flex bearing more than the lower one.  We tried aluminum shielding the top bearing assembly from the heatsink IR source and managed to reverse the metioned thermal slope in the thrust plots, but after shielding the bottom one we could reduce it but still coundn't completely get rid of this thremal drift artifact.  Currently we are just living with it.

Thank you for this answer.
This gives a sense of how sensitive is the system and hairy to calibrate and use.

If due to the generator's IR radiation this slope changing effect should then be the same with the Null Test RF load, but the 3 charts of fig.20 show disparate results, 11:13 downward trend after power off like ones of fig.19, 11:23 upward trend during power on and then resuming same slope as before, 11:28 no discernible change of slope at all during power on neither after power off. Unless the closely paced successive runs change the successive heat equilibriums/exchanges with hard to predict outcomes ? If there is long period complex drifts/swings in the system then I'm probably trying to guess at too few samples here... it's just frustrating to see those drifts at comparable magnitudes as the measured effect.

I understand that a thermally induced displacement of mass could mimic a sharp rise in thrust (as it would be the second derivative of temperature) but can't make it quantitatively, while a IR induced thermal effect on the spring constant of the bearings can reach the magnitude observed, but apparent thrust would then be proportional to temperature : couldn't explain the sharp rise has it would then imply instant rise of temperature.

Title: Re: EM Drive Developments
Post by: Star-Drive on 09/11/2014 11:22 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254150#msg1254150">Quote from: JohnFornaro on 09/11/2014 08:16 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254047#msg1254047">Quote from: Rodal on 09/11/2014 04:15 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1253089#msg1253089">Quote from: JohnFornaro on 09/09/2014 02:46 PM</a>
3. Is the torsion pendulum the only way to test a device of this sort on Earth?

There are several types of small thrust measurement devices. ...

Hey, thanks!  Great overview! 1, 2, & 4?

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254131#msg1254131">Quote from: sghill on 09/11/2014 07:33 PM</a>
Best to ignore Goatguy ...

Sheesh, what a diatribe.  Speaking as a Capricorn, he is an embarrasment to my sign.

Still, a pet peeve of mine regarding these not yet proven technologies is the discussion about future "expectations", based on "theoretical models", and the like.

Quote from: the Brady, White, March paper
Based on test data and theoretical model development, the expected thrust to power for initial flight applications is expected to be in the 0.4 newton per kilowatt electric (N/kWe) range, which is about seven times higher than the current state of the art Hall thruster in use on orbit today.

The following predictions of missions to Saturn and all strain credulity, because they are merely the application of numbers to an equation, and do not flesh out the many requirements needed to actually carry out one of these missions, other than the single metric of "0.4 newton per kilowatt electric (N/kWe)".

It's not acceptable to handwave such missions into a suggested plausible existance based only on "theoretical models".  It's not like the technology, if proven, has no perceived utility.

Anyhow, it is fascinating to follow the real discussion going on above.

Oh.  And I can easily lowball your sister. I'll run those ads for $5M.

John:

"It's not acceptable to handwave such missions into a suggested plausible existance based only on "theoretical models".  It's not like the technology, if proven, has no perceived utility."

 The NASA managers who control the research dollars have to understand the value proposition in the pursuit of a new propulsion technology or they won't support developing it, period.  And no, they didn't at first perceive and appreciate the utility of this Q-Thruster or Dr. Woodward's near equivalent Mach-Effect Thruster (MET) technologies until we performed a whole family of Copernicus orbital scenarios conservatively based on same, which the JPC report just touched on.  It's really that simple and the managers have at least now been told the theoretical and developmental benifits and risks in the pursuit of this unproven propulsion science and technology, so they can now make an educated choice to pursue it or not based on our orbital analysis work and the current sad state of affairs in the US human spaceflight program.  In other words chemical rockets just won’t cut it going out past Mars even with a robust human spaceflight budget and positive direction from the Whitehouse!  If we could use nuclear rockets, other choices would be availabe for our propulsion needs, but sadly the nuclear propulsion venue is not available to the US space program due to political issues we all know of, unless of course a fusion power breakthrough shows up on our doorsteps...

Best,

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/12/2014 01:16 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254383#msg1254383">Quote from: Star-Drive on 09/11/2014 11:22 PM</a>
The NASA managers who control the research dollars have to understand the value proposition in the pursuit of a new propulsion technology or they won't support developing it, period.

Paul, thanks for the engagement.  I totally get the justification argument.  I mean, name one AIAA paper where, among the conclusions, they state; "No, thanks all the same, we got tons of money.  Really."

The fact of the matter is, all that we have is chemical rocketry, and that for the forseeable future.   Your all's effort seems appropriately funded, and you have your work cut out for you.  If the managers you are beholden to must be reminded at every turn that your work has significant potential, one has to wonder at their attention span.

At the same time, you are jumping, without justification in my mind, way too far into the speculative future.  Your task, as they say, is to float the damn thing on the tabletop.  Just get us and twenty tons of stuff to Luna, willya?  By a low energy orbit, if you can.  The rest will follow, but only after that useful demonstration

If Rodal's analysis is faulty, get into those mathematical weeds.  If he has pointed out a weakness in your procedures, acknowledge it and take steps to address his argument.

Title: Re: EM Drive Developments
Post by: Rodal on 09/12/2014 01:59 AM
John (Fornaro) and Paul (March),

The experimental results and possible explanations are not trivial, addressing and studying them will take patience and time.  There are subtle issues involved because of the extremely small forces being measured. 

There is no hurry. 

I think that we have a great line of communications !.  Let's keep it going. :D


To Infinity and Beyond (or to wherever we can get with the propulsion we have)

Jose' Rodal

Look up at the stars. Try to make sense of what you see. Be curious.
Title: Re: EM Drive Developments
Post by: Star One on 09/12/2014 06:30 AM
I hope this isn't inappropriate but can I just thank you all for your posting in this thread, hearing from people at the coal face of research has been fascinating to read even if as a lay person I've only understood about fifty percent of it.:)
Title: Re: EM Drive Developments
Post by: Star-Drive on 09/12/2014 12:58 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254413#msg1254413">Quote from: Rodal on 09/12/2014 01:59 AM</a>
John (Fornaro) and Paul (March),

The experimental results and possible explanations are not trivial, addressing and studying them will take patience and time.  There are subtle issues involved because of the extremely small forces being measured. 

There is no hurry. 

I think that we have a great line of communications !.  Let's keep it going. :D


To Infinity and Beyond (or to wherever we can get with the propulsion we have)

Jose' Rodal

Look up at the stars. Try to make sense of what you see. Be curious.

Jose':

I've been involved in testing Dr. Harold Sonny White's Q-Thruster approach to exotic propulsion for seven plus years now, and Dr. James F. Woodward's Mach-Effect (M-E) work for sixteen years.  (I started down this road in March of 1998 while working for Lockheed-Martin at JSC working as an electrical engineer on the NASA Space Shuttle program.)  I summarize my M-E AKA Woodward Effect research in three STAIF papers published in 2004, 2006 and 2007.  I know Dr. Woodward's body of M-E work extensively having been to his lab at CSUF a number of times now, and IMO Woodward has been seeing real forces in his M-E Thruster (MET) experiments for years. 

These latest experimental results on the Q-thruster is just trying to take Jim's work one step further by attempting to quantize the gravitational field in a manner consistent with Quantum Mechanics (QM), Plasma Physics and General Relativity Theory (GRT).  In other words if you are not already familiar with this body of work that Dr. Woodward started in 1982, you need to perform due diligence in reading several of the papers that Dr. Woodward, Dr. White and I have written over this time period.  Primarily I'm just the electrical engineer turned experimental physicist that is trying to make this exotic propulsion business work, for without something like it, humanity is doomed to stay inside the asteroid belt for the foreseeable future.  In the meantime if you can't find the papers in question e-mail me a note and I'll be glad to get them to you.

Best,

Title: Re: EM Drive Developments
Post by: JasonAW3 on 09/12/2014 02:00 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254383#msg1254383">Quote from: Star-Drive on 09/11/2014 11:22 PM</a>

"It's not acceptable to handwave such missions into a suggested plausible existance based only on "theoretical models".  It's not like the technology, if proven, has no perceived utility."

  It's really that simple and the managers have at least now been told the theoretical and developmental benifits and risks in the pursuit of this unproven propulsion science and technology, so they can now make an educated choice to pursue it or not based on our orbital analysis work and the current sad state of affairs in the US human spaceflight program.


So, unless I am VASTLY mistaken, the only real risks that I can see here are a possible waste of Time, Money and a small amount of resources while pursuing a phenomena that even NASA acknowledges as being "Interesting".  Should it be proven wrong, then I don't see any appreciable fallout, as everyone involved seems to be seeing what they are acknowledging as a real induced motion of some kind.

     If it proves wrong, there doesn't appear to be any attempt a fraud, so no one takes a hit for that, extensive precautions are being taken to ensure that no other inflences could be responsible for what is happening, and the worst fall out I can see is the equivelent of the loose connector in teh CERN laboritiries that made everyone think that they may have spotted FTL neutrinos.  Basicly, everyone said, "OOPS, our bad!" and pretty much went on from there.

     So, if this doesn't prove out, it would be much like Edison's 1000 failures before he perfected the Light Bulb. He didn't fail 1000 times, he simply found 1000 ways that the light bulb wouldn't work.

     With that in mind, I say go for it and let's see where this leads!

Title: Re: EM Drive Developments
Post by: aceshigh on 09/12/2014 02:25 PM

Paul March is one of the nicest guys around. I have seen him taking flak and never altering his manners.


GoatGuy at NBF (they made a new article with the things Paul just published above) is now saying it´s obvious the EM Drive (or any other propellantless drive) is a perpetual motion machine because using a simple mission to Saturn in less than a year proves the energy needed to get there is orders of magnitude larger than the electrical energy input.

Quote from: GG
Mission-to-Saturn.
286 days.

Half that is acceleration, and half is deceleration. It only makes sense to keep the thruster "on" the entire trip, to minimize trip time. Half is about 12,000,000 seconds. This is an important number.

Acceleration is 0.0091 m/s² Since V = at and we know both t and a, then V is about 109,000 m/s or 109 km/s. Awesome! I wonder how much kinetic energy it has? Well, that is Ek = ½mV² and our mass is 90,000 kg. OK, easy-peasy. That's then 537,000,000,000,000 joules. about 120 kilotons of TNT as kinetic energy. Impressive!

Now, let's see. 2,000,000 watts for 13,000,000 seconds is what... 26,000,000,000,000 joules. Well then ... it looks like our spacecraft has 20.6× the kinetic energy as the electrical energy invested into its motion.



well, I guess that in a QM Drive, in theory, the electric energy only allows you to kind of access the much bigger energies of the quantum vacuum?

Title: Re: EM Drive Developments
Post by: Star One on 09/12/2014 02:41 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254525#msg1254525">Quote from: aceshigh on 09/12/2014 02:25 PM</a>
Paul March is one of the nicest guys around. I have seen him taking flak and never altering his manners.


GoatGuy at NBF (they made a new article with the things Paul just published above) is now saying it´s obvious the EM Drive (or any other propellantless drive) is a perpetual motion machine because using a simple mission to Saturn in less than a year proves the energy needed to get there is orders of magnitude larger than the electrical energy input.

Quote from: GG
Mission-to-Saturn.
286 days.

Half that is acceleration, and half is deceleration. It only makes sense to keep the thruster "on" the entire trip, to minimize trip time. Half is about 12,000,000 seconds. This is an important number.

Acceleration is 0.0091 m/s² Since V = at and we know both t and a, then V is about 109,000 m/s or 109 km/s. Awesome! I wonder how much kinetic energy it has? Well, that is Ek = ½mV² and our mass is 90,000 kg. OK, easy-peasy. That's then 537,000,000,000,000 joules. about 120 kilotons of TNT as kinetic energy. Impressive!

Now, let's see. 2,000,000 watts for 13,000,000 seconds is what... 26,000,000,000,000 joules. Well then ... it looks like our spacecraft has 20.6× the kinetic energy as the electrical energy invested into its motion.



well, I guess that in a QM Drive, in theory, the electric energy only allows you to kind of access the much bigger energies of the quantum vacuum?

Speaking with a complete ignorance of this guy's past articles, should we take much note of what he says?

Title: Re: EM Drive Developments
Post by: sghill on 09/12/2014 03:06 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254532#msg1254532">Quote from: Star One on 09/12/2014 02:41 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254525#msg1254525">Quote from: aceshigh on 09/12/2014 02:25 PM</a>
Paul March is one of the nicest guys around. I have seen him taking flak and never altering his manners.


GoatGuy at NBF (they made a new article with the things Paul just published above) is now saying it´s obvious the EM Drive (or any other propellantless drive) is a perpetual motion machine because using a simple mission to Saturn in less than a year proves the energy needed to get there is orders of magnitude larger than the electrical energy input.

Quote from: GG
Mission-to-Saturn.
286 days.

Half that is acceleration, and half is deceleration. It only makes sense to keep the thruster "on" the entire trip, to minimize trip time. Half is about 12,000,000 seconds. This is an important number.

Acceleration is 0.0091 m/s² Since V = at and we know both t and a, then V is about 109,000 m/s or 109 km/s. Awesome! I wonder how much kinetic energy it has? Well, that is Ek = ½mV² and our mass is 90,000 kg. OK, easy-peasy. That's then 537,000,000,000,000 joules. about 120 kilotons of TNT as kinetic energy. Impressive!

Now, let's see. 2,000,000 watts for 13,000,000 seconds is what... 26,000,000,000,000 joules. Well then ... it looks like our spacecraft has 20.6× the kinetic energy as the electrical energy invested into its motion.



well, I guess that in a QM Drive, in theory, the electric energy only allows you to kind of access the much bigger energies of the quantum vacuum?

Speaking with a complete ignorance of this guy's past articles, should we take much note of what he says?

You should not.  I'm shocked to see him quoted on this thread when we have direct practitioners- including a principle Eagleworks scientist- engaged in open discussion for our benefit.  They could have taken it off-line, but didn't, and that bomb-throwers quotes only serve to shut down the benefits we're getting.

Title: Re: EM Drive Developments
Post by: Rodal on 09/12/2014 03:49 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254494#msg1254494">Quote from: Star-Drive on 09/12/2014 12:58 PM</a>
Jose':

I've been involved in testing Dr. Harold Sonny White's Q-Thruster approach to exotic propulsion for seven plus years now, and Dr. James F. Woodward's Mach-Effect (M-E) work for sixteen years. .....
Paul,

Thank you for pointing this out.  I have read with interest several of Dr. Woodward, and Dr. White's papers, including some of your own papers.  It is admirable, in  a sense, to have people willing to pursue research avenues that are not most popular, or commonly accepted.  Concerning Dr. Woodward's, theory, to cut to the chase, as Dr. Woodward himself accepts with a smile in the following presentation (
[ http://www.youtube.com/watch?v=hn8hqX9JBOE#t=2468 ]
where I have on purpose timed it to when the question is asked, otherwise advance to the end of the presentation at 41:08 minutes (2468 sec)) the obvious question to pose to Dr. Woodward is:

If your interpretation of Mach's principle is that inertia is a gravitational reaction from the rest of the Universe (no matter how distant from your center of mass) how come that reaction takes place INSTANTLY ?

In other words, in Dr. Woodward's theory, the propagation of this gravitational reaction responsible for inertia, has INFINITE speed, which is problematic in a Theory of Relativity (where we usually associate gravitational waves to travel at the speed of light).

Dr. Woodward answers with a smile, that "presumably" it is a radiation reaction attributable to Wheeler–Feynman absorber theory.  With his smile and frank facial expression he acknowledges that this is, let's say... problematic?

Because we know that:

A) The Wheeler–Feynman absorber theory assumes that the solutions of the electromagnetic field equations must be invariant under time-reversal symmetry, there is no distinction between past and future.

B)  It therefore assumes that elementary particles are not self-interacting. This is a big drawback of this theory. Indeed, as demonstrated by Hans Bethe, the Lamb shift necessitated a self-energy term to be explained. Feynman and Bethe had an intense discussion over that issue and eventually Feynman himself stated that self-interaction is needed to correctly account for this effect.

C) Wheeler and Feynman conceived of this theory before the Weak Force was understood as it is nowadays.  It is known that the Weak Force implies time-symmetry breaking and gives an arrow of time.  Hence the Weak Force is incompatible with the  Wheeler–Feynman absorber theory, in this sense.

I think that it was wise that you, Dr. White, et.al., decided that <<This paper will not address the physics of the quantum vacuum plasma thruster (QVPT), but instead will describe the recent test campaign>> (Abstract of "Anomalous Thrust Production..." paper).

In that vein, I think it would be best to discuss the experiments without addressing any controversial physical explanation for the time being.

 

Title: Re: EM Drive Developments
Post by: aceshigh on 09/12/2014 04:15 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254543#msg1254543">Quote from: sghill on 09/12/2014 03:06 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254532#msg1254532">Quote from: Star One on 09/12/2014 02:41 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254525#msg1254525">Quote from: aceshigh on 09/12/2014 02:25 PM</a>
Paul March is one of the nicest guys around. I have seen him taking flak and never altering his manners.


GoatGuy at NBF (they made a new article with the things Paul just published above) is now saying it´s obvious the EM Drive (or any other propellantless drive) is a perpetual motion machine because using a simple mission to Saturn in less than a year proves the energy needed to get there is orders of magnitude larger than the electrical energy input.

Quote from: GG
Mission-to-Saturn.
286 days.

Half that is acceleration, and half is deceleration. It only makes sense to keep the thruster "on" the entire trip, to minimize trip time. Half is about 12,000,000 seconds. This is an important number.

Acceleration is 0.0091 m/s² Since V = at and we know both t and a, then V is about 109,000 m/s or 109 km/s. Awesome! I wonder how much kinetic energy it has? Well, that is Ek = ½mV² and our mass is 90,000 kg. OK, easy-peasy. That's then 537,000,000,000,000 joules. about 120 kilotons of TNT as kinetic energy. Impressive!

Now, let's see. 2,000,000 watts for 13,000,000 seconds is what... 26,000,000,000,000 joules. Well then ... it looks like our spacecraft has 20.6× the kinetic energy as the electrical energy invested into its motion.



well, I guess that in a QM Drive, in theory, the electric energy only allows you to kind of access the much bigger energies of the quantum vacuum?

Speaking with a complete ignorance of this guy's past articles, should we take much note of what he says?

You should not.  I'm shocked to see him quoted on this thread when we have direct practitioners- including a principle Eagleworks scientist- engaged in open discussion for our benefit.  They could have taken it off-line, but didn't, and that bomb-throwers quotes only serve to shut down the benefits we're getting.

Fact is, he keeps throwing his bombs, and at least, I am not knowledgeable enough in this advanced physics subjects to expose flaws in his reasoning. And there are plenty of people who do listen to him.

That's why I quoted him here: expecting people to prove him wrong. In the process, I also learn something.

 

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/12/2014 04:43 PM

Quote from: goatguy
Acceleration is 0.0091 m/s² Since V = at and we know both t and a, then V is about 109,000 m/s or 109 km/s. Awesome! I wonder how much kinetic energy it has? Well, that is Ek = ½mV² and our mass is 90,000 kg. OK, easy-peasy. That's then 537,000,000,000,000 joules. about 120 kilotons of TNT as kinetic energy. Impressive!

Now, let's see. 2,000,000 watts for 13,000,000 seconds is what... 26,000,000,000,000 joules. Well then ... it looks like our spacecraft has 20.6× the kinetic energy as the electrical energy invested into its motion.

Is the math here correct or is it not?

I don't care much about his style of writing, nor do I care so much that someone else is "shocked to see him quoted on this thread".  Is this "easy-peasy" math correct or not?

Intuitively, it does not seem likely at all that a 2MWe spacecraft, which includes payload and the necessary reactor and shielding, could transport 90mT to Saturn's moons in the time suggested.  I believe that the 90mT figure has been completely concocted. 

The 300KWe, 788 day manned fly-by only mission to Phobos/Deimos is also sketchy, at least from this armchair.  Here, the authors believe that somehow a 70 mT stack is assembled in a presumably lunar DRO.  The reader is left to assume that this spacecraft has been appropriately analyzed and suggested.

But hey.

Quote from: Rodal
If your interpretation of Mach's principle is that inertia is a gravitational reaction from the rest of the Universe (no matter how distant from your center of mass) how come that reaction takes place INSTANTLY ?

This question has been asked over and over again, but it has not yet been answered by any of the people who are experimenting with these drives, nor any other physicist studying the problem of inertia, that I can tell.

Just sayin'. 

I'm personally happy to read the back and forth regarding the experimental apparatus.

Title: Re: EM Drive Developments
Post by: Rodal on 09/12/2014 05:22 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254587#msg1254587">Quote from: JohnFornaro on 09/12/2014 04:43 PM</a>

Quote from: Rodal
If your interpretation of Mach's principle is that inertia is a gravitational reaction from the rest of the Universe (no matter how distant from your center of mass) how come that reaction takes place INSTANTLY ?

This question has been asked over and over again, but it has not yet been answered


Well, yes, it has been answered by Dr. Woodward himself, as I show in the YouTube clip above.  The problem is that Dr. Woodward's explanation relies on the old Wheeler–Feynman absorber theory, which was abandoned by Feynman himself (as I point out above) because of the Lamb shift effect. 

Most importantly, this answer is incompatible with our present knowledge of the Weak Force (as I point out above).   The Weak Force is the only fundamental force that breaks parity-symmetry, and similarly, the only one to break CP-symmetry. 

Has anybody else pointed out the incompatibility of Dr. Woodward's answer (Wheeler–Feynman absorber theory) with the arrow of time shown by the Weak Force?

Bottom line:   I think it would be best to discuss the experiments without addressing any controversial physical explanation for the time being.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/12/2014 05:33 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254592#msg1254592">Quote from: Rodal on 09/12/2014 05:22 PM</a>
Well, yes, it has been answered...

That would be the case if and only if any answer were acceptable without experimental proof or without requiring the "answer" to reconcile other theoretical incompatabilities.  Savvy?

As I said, I'm personally happy to read the back and forth regarding the experimental apparatus.

Title: Re: EM Drive Developments
Post by: JasonAW3 on 09/12/2014 06:06 PM
Rodal,

     Unless my understanding of what is being implied here is incomplete, which it probably is, it seems to imply that Gravity and Space itself are closely tied together.

     The Albercrombie Drive, for example, uses weird matter to distort Space in a fashion similar to that postulated in Inflation Theory, allowing the craft generating this distortion to ride behind a wave of compacting Space while riding the wave of expanding space behind it.

     What seems to be implied here is that Space can be distorted in the same way using Gravity, if one were able to create a directionalized gravity well.

     So, hypothetically, if one were to create a toroidal magnetic field off sufficent strength to contain a high energy plasma accellerated along the magnetic lines of force, from south pole to north, through the center of the torus and back out again, accellerating the plasma to relativistic velocities, would not such a system also produce an expansion of space at the southern pole of the field while compressing space at the northern pole of the field, in a similar manner to the Albercumbie Drive?  Mind you, by accellerating the Plasma to Relativistic velocities, we amplify it's effective mass (and gravity) and its' effective distortion of space, proportionally.

     Mind you this is both an oversimplification of my thoughts and likely incorrect, but if Gravity is tied to Space in the manner that is seeminlg applied, then in what way is this hypothisys incorrect?

     The only reason I'm posting this here is due to Rodal's previous post concering the instanatious nature of the effect of gravity.  As such, it could be argued that this is an outgrowth of the EM Drive discussion.
Title: Re: EM Drive Developments
Post by: Rodal on 09/12/2014 06:36 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254605#msg1254605">Quote from: JasonAW3 on 09/12/2014 06:06 PM</a>
Rodal,

         The Albercrombie Drive, for example, uses weird matter to distort Space in a fashion similar to that postulated in Inflation Theory...
Rodal's previous post concering the instanatious nature of the effect of gravity.  ..
Jason,

1) The Alcubierre drive needs a large amount of negative mass (not antimatter, not dark matter, but negative mass) to distort spacetime.  The expansion of spacetime that occurred during Inflation was not due to negative mass.  Problems: A) Where is the negative mass going to come from ? and B) It has been shown that the distortion of spacetime that would enable the Alcubierre drive to travel faster than light would also enable it as a time machine, including a time machine enabling time travel to the past.  There are huge problems with that, not the least being a number of paradoxes.


2) My previous post discussed that Dr. Woodward's answer to the fact that his theory implies instantaneous reaction is incompatible with experimental results: it relies on an old theory of Wheeler and Feynman (late 1940's) that Feynman later abandoned due to the experimental results of the Lamb Shift and most importantly is incompatible with our experimental results for the Weak Force.


____

Once we thoroughly understand the experimental results we can proceed to discuss possible physical interpretations.

Title: Re: EM Drive Developments
Post by: GoatGuy on 09/12/2014 07:28 PM
Hello, folks.  From a poster's recommendation at NextBigFuture, I have come here to participate in this and other fora, If y'all will have it.  Previous posts at NBF (of mine) have been pasted here;  so far, I see little love for the position(s) I've taken. 

To "short circuit" the discussion a bit, I have determined that a VERY simple pair of equations brings into question whether the EM-Thruster or Q-Drive is a perpetual-motion / over-unity energy generator or not.  These:

if [k] is the EM-drive thrust factor, in Newtons-per-Watt (which has been widely used and quoted) then...

V = 1/k ... is the velocity of the Q-device, where the kinetic energy it creates matches the input energy and...
V = 2/k ... is the velocity of a free-floating spacecraft employing the EM-thruster, where the TOTAL energy invested equals the TOTAL imparted kinetic energy of the spacecraft.

These are important equations; I have not so far discerned that there is a contrary-position regarding the over-unity aspect that these equations give users of the EM-drive device(s).  Using the "usual physics" equations for energy, velocity, acceleration, time, mass, force, distance (delta-d) and so on, both of these are really straight forward to prove.  Even if all you do is the empirical math to show applicability. 

In short:

Ek = ½mV²   ... kinetic energy as a function of V
W = Fd   ... work (energy) as function of force and delta-distance (don't know how to get delta typed in)
V = at  ... delta V as function of acceleration and time (assuming constant)
F = ma ... the usual physics, so
a = F/m 

And then some obvious (and algebraically correct) substitutions:

W/t = Fd/t
V = d/t    (change in distance over time, nothing new here...)
W/t = FV
W/t is "power", or P, so
P = FV = maV  (again, nothing unusual)

When F = k·Pin   (k is newtons per watt, Pin is watts) then substituting...

P = k·Pin·V ... now just setting the "critical over-unity point" where both P and Pin are the same (P = Pin) then:
P = k·P·V
1 = k·V
V = 1/k  by rearrangement

That one was easy, agreed?  And correct, classical Newtonian physics.  The second case is a bit harder to prove, but still within reach of ordinary algebra:

Ek = ½mV²   ... kinetic energy as a function of V, again.
V = at ... again, now substitute
Ek = ½ma²t²  and remembering that [F = ma]...
Ek = F²t²/(2m)

Since the spacecraft/thruster will consume Ein = Pin·t  (power times time), then setting Ein = Ek (total energy in, to total kinetic energy of free-flying craft), we get:

Ek == Ein
Ek = Pin·t
Pin·t = F²t²/(2m), and solving for t:
t = 2·Pin·m/F², which is the time at which the kinetic energy of the craft matches the total input energy, and
V = at
V = a·( 2·Pin·m/F² )   (and recalling F = k·Pin AND a = F/m, and a = k·Pin/m...)
V = a·( 2·Pin·m/(k²Pin²) )
V = ( k·Pin/m ) · ( 2·Pin·m/(k²Pin²) ), and with algebraic rearrangement
V = ( 2·k·Pin²·m ) / ( m·k²Pin² ), then cancelling things on top and bottom:
V = 2 / k

Where this then is the velocity of the craft considered in its OWN reference frame, as attaining an amount of delta-V, which equates to kinetic energy, that is EQUAL to the amount of electrical power pumped into the thruster.  ANY additional velocity then gives the craft, in its own reference frame, MORE kinetic energy than has been invested into it by way of the thruster. 

At (V > 1/k), it is a free energy device.

Thanks for the consideration.  I hope there will be a reply that answers this fundamental flaw.

GoatGuy
Title: Re: EM Drive Developments
Post by: Rodal on 09/12/2014 07:36 PM
Paul March,

OK, Let's try to discuss the experimental set-up.  From one of your previous posts, I understand that the inverted pendulum arm is made of this: http://www.amazon.com/Faztek-15QE1515UL-Aluminum-T-Slotted-Extrusion/dp/B008MQA11C .

Going to the company's website:  http://www.faztek.net/technical.html, I understand that the "Faztek 15QE1515UL Aluminum 6063-16 T-Slotted Ultra Light Extrusion with Clear Anodize Finish, 1-1/2" Width x 1-1/2" Height" you use for the inverted pendulum arm has the following Moments of Inertia (in bending):

Ix = Iy = 0.1802 in^4

and the following modulus of elasticity:

E = 10^6 psi

I also understand from your prior post that this moment arm is restrained from rotations around the X and Y (horizontal) axes at the bottom support by two Riverhawk C-flex torsion bearings, and << the center of the two C-flex bearing blocks is 2.38" above and below the centerline of the 24.00" long by 1.50" square aluminum pendulum arm.  The long end of the pendulum arm is 15.5" from the torque pendulum's center of rotation, which makes the other short-end of the pendulum arm 8.5">>.

What I need is the arm distance between the bottom support and the supported platform with weight. If I interpreted correctly what you wrote, this length "l" is:

l = 15.5" - 2.38"=13.12 inches =0.33325 meters

I needed the elastic spring constant of the pendulum arm (in swinging motion).  I understand that the number you provide << The Riverhawk C-flex torsion bearing's spring constant is a nominal 0.007 in-Lb/deg>> must be for torsion around the vertical "Z" axis normal to the horizontal plane, because this spring constant is extremely low.

So, my interpretation is that we therefore have to calculate the (bending) spring constant of the pendulum arm (in swinging motion).  Interpreting the two Riverhawk C-flex torsion bearings constraints as a cantilevered support for the pendulum arm, and using the suggested beam deflection formula in the faztek website for a cantilevered beam acted by a force at the free end:

MaximumDeflection = delta = F * (l^3) / (3 E I )

The (bending) spring constant of the pendulum arm (in swinging motion) for rotation around the X and Y horizontal axes is:

k = F/delta = (3 E I ) / (l^3) = 3 * (10^6 lbf/in^2) * (0.1802 in^4) /(( 13.12 in)^3) = 2393.726 lbf/in
k =( 2393.726 lbf/in) *( 4.44822162 N/lbf) / (0.0254 in/m) = 4.192*10^5 N/m

Is my interpretation correct ?
Title: Re: EM Drive Developments
Post by: Rodal on 09/12/2014 07:52 PM
@ Paul March,

We also needed the total supported weight (of all the supported equipment, the drive AND the platform on top of the pendulum arm).  I understand that this is 25 lbf (although I wonder whether you included the weight of the supporting platform resting on the pendulum arm as well ?)

Taking this as the total supported mass:

M = 25 lb = 25 lb * (0.453592 kg/lb) = 11.3398 kg

We get a ratio of (swinging motion) spring constant to mass of:

k/M =( 4.192*10^5 kg*(m/s^2)/m)/11.3398 kg = 3.6968*10^4 1/(s^2)

and the gravity term is:

g/l = (9.80665 m/(s^2))/(0.33325 m) = 29.4273 1/(s^2)

So, the stiffness-to-mass term is 1256 times greater than the gravity term, and the frequency (in swinging motion around the X and Y horizontal axes) is:

f = (1/(2 Pi))Sqrt[3.6968*10^4 1/(s^2) - 29.4273 1/(s^2)] = 30.59 Hertz

[I presume that this is an upper bound for the frequency because it assumes that the bearings are providing a cantilevered condition with no swinging flexibility around X an Y, and it presumes that 25 lbf is the total weight supported on top of the pendulum arm, including the platform]
Title: Re: EM Drive Developments
Post by: Rodal on 09/12/2014 08:26 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254645#msg1254645">Quote from: GoatGuy on 09/12/2014 07:28 PM</a>
Hello, folks.  From a poster's recommendation at NextBigFuture, I have come here to participate in this ....
Thanks for the consideration.
GoatGuy

@GoatGuy,

What is your physical explanation for the experimental measurements (of at least 6 different drives) at NASA Eagleworks?, including

A)  dependence on the Teflon dielectric resonator (without the dielectric resonator they measured zero thrust) and

B) that when they turned the drive (by 180 degrees rotation around the Z vertical axis), with the dielectric resonator to the "left" instead of to the "right", they got a similar numerical thrust result, but now directed to the opposite direction as compared to the previous orientation (showing a thrust measurement vector dependent on physical orientation of the drive) ?

Title: Re: EM Drive Developments
Post by: frobnicat on 09/12/2014 08:48 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254645#msg1254645">Quote from: GoatGuy on 09/12/2014 07:28 PM</a>
Hello, folks.  From a poster's recommendation at NextBigFuture, I have come here to participate in this and other fora, If y'all will have it.  Previous posts at NBF (of mine) have been pasted here;  so far, I see little love for the position(s) I've taken. 

Speaking for myself as a relatively newcomer, welcome onboard.

Quote
.../...
At that point, it is a free energy device.

Thanks for the consideration.  I hope there will be a reply that answers this fundamental flaw.

GoatGuy

Well, I did post similar argument : http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240286#msg1240286 (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1240286#msg1240286)
I don't remember counter arguments : I guess no one can seriously object that a reactionless drive with such Thrust/Power ratio is indeed either a free energy device, or pumping energy from somewhere (see below).
But this very serious and immediate practical consequence seems to be less excitingly investigated than (beyond my understanding) theoretical inconsistencies of the aspects of Machian inertia for critics, and the possibilities of delivering grand pianos to Saturn moons for enthusiasts.

A few caveats :

Your calculations are Newtonian mechanics, when approaching c speeds or Thrust/Power ratios below 1/c its no longer valid, and indeed we have the photon rocket as an example of a "reactionless" drive that is not a free energy device. The claimed thrust/power = k ratio is more than 2 orders of magnitude above that, so it's ok to go Newtonian as a good approximation, also it should be acknowledged and stressed that as soon as a purported k factor is even so slightly better (higher) than 1/c of the photon rocket, then there is energy conservation breaking for some inertial reference frame (also maybe not practical to exploit).

Quibbling : "velocity of the craft considered in its OWN reference frame" could be misread as "the frame of its acquired speed now" (absurd as it would be 0 by definition, but yet). Could we say "in the inertial reference frame of its departure" or something like that (English not my native tongue) ?

Ok so we are breaking energy conservation, great : Noether's theorem show this implies reality not to be time invariant. Hard to swallow much much below cosmological timescales.

Ok so energy is conserved but the acquired energy is pumped from vacuum, not free energy but rel cheap energy, great : quoting myself  "tap into vacuum zero-point energy, which would no longer be zero-point... My guess is that all this virtual agitation down there is like a thermal bath and nothing useful (in terms of net work) can come out of it (second principle...) but please someone qualified help." In context :
http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243932#msg1243932 (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243932#msg1243932)

Penultimate point : if the k factor somehow decays with acquired speed (relative to start frame of reference) this could mitigate the free energy aspect. But then the mission profiles are not the same... and it's really difficult to see what would make the system "remember" this particular initial reference frame, and it doesn't prevent the drive to be a free energy generator relative to some well chosen arbitrary inertial reference frame.

Last point : the k=0.4 N/kW figure used for the mission profiles implies possible breakeven starting at speeds of 1/k=2.5km/s relative to a fixed frame. That is if you mount the drive on a rotor, and re-inject the energy of the shaft into the drive, you have not only a theoretical but an almost practical free (or rather cheap) energy generator : the rim of fastest wheels for energy storage is around 2km/s. (Take into account the efficiency of the closed loop, if 0.5 then turn at 5km/s tangential speed, mechanically harder to get at but still conceivable without unobtainium). I'd like to see the experiment done on a freely rotating arm, in an otherwise rotationally symmetric setting around the axis.

Title: Re: EM Drive Developments
Post by: francesco nicoli on 09/12/2014 09:16 PM
Anyway, great to have GoatGuy on this forum. NBF is an interesting platform for discussion but faaar less professional than here on many subjects; GoatGuy is by far the more informed discussant there and will add lot of quality here as well. Welcome!
Title: Re: EM Drive Developments
Post by: GoatGuy on 09/12/2014 09:21 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254667#msg1254667">Quote from: Rodal on 09/12/2014 08:26 PM</a>
What is your physical explanation for the experimental measurements (of at least 6 different drives) at NASA Eagleworks?, including

A)  dependence on the Teflon dielectric resonator (without the dielectric resonator they measured zero thrust) and

B) that when they turned the drive (by 180 degrees rotation around the Z vertical axis), with the dielectric resonator to the "left" instead of to the "right", they got a similar numerical thrust result, but now directed to the opposite direction as compared to the previous orientation (showing a thrust measurement vector dependent on physical orientation of the drive) ?

I'm sorry, how does that address [V > 1/k case, and V > 2/k cases], which was the point of my posting?   I am not questioning whether something was measured.  What I am questioning is whether such a finding leads immediately to declaring the device a free energy device after some amount of power is invested in its motion in space.  That's, all.

GoatGuy

EDIT / postscript:  special alert - I'm aware that when 'k' is equal or less than 1/299,792,000 newtons per watt, conservation of energy is preserved, as that particular number is reserved for perfect radiators of electromagnetic energy.  They manage not to break the conservation of energy criterion because they would have to "burn up" a lot of matter (say, optimally, matter-antimatter at perfect efficiency!) ... and the amount of speed/thrust then becomes almost exactly what you'd expect for a rocket that just as efficiently exhausted real reaction mass.   

GoatGuy

Title: Re: EM Drive Developments
Post by: Rodal on 09/12/2014 09:23 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243932#msg1243932">Quote from: frobnicat on 08/17/2014 12:04 AM</a>

Virtual particles of the vacuum on the other hand don't appear to define a frame of reference, though they might define an "inertial reference" (tm) : Casimir effect for instance don't show different behaviour on different inertial frames (Lorentz invariant, no reference of what would be an absolute 0 speed relative to vacuum) while dynamical Casimir effect allows to measure acceleration in absolute terms (can tell an absolute 0 acceleration relative to it)....


We don't really need to go there either:top physicists nowadays do NOT explain the Casimir effect in terms of "negative mass" or "negative energy" but as a van der Waal (charge) force just as in the Lamb shift.  Pauli, Feynman,  de Witt were known to express their dissatisfaction with the quantum vacuum explanation. Swchinger found it so distasteful that he came up with his own successful explanation.  To me the failure (in his own attempt) by Casimir himself to explain the fine structure constant  in terms of the quantum vacuum should be telling enough.  Ditto for his failure to explain and predict even the sign of the Casimir force for different shapes (instead of plates).


Why don't we discuss the experimental results and physical explanations for them instead of tearing up controversial theories?

ADDED: To me tearing up a controversial theory is like Don Quixote charging against the windmills.  Addressing and explaining the experimental results instead is analogous to physicists explaining quantum mechanics experimental results in the early 20th century to come up with the theory of Quantum Mechanics: the most successful theory to explain nature, yet it was thrusted on us by experimental results so strange that caused Bohr to say <<If quantum mechanics hasn't profoundly shocked you, you haven't understood it yet.>> and Feynman to say <<I think I can safely say that nobody understands quantum mechanics.>>



Title: Re: EM Drive Developments
Post by: Rodal on 09/12/2014 09:31 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1243932#msg1243932">Quote from: frobnicat on 08/17/2014 12:04 AM</a>
I'd like to see some qualified explanations with Feynman diagrams showing how it's impossible to push on virtual particles (unless they are made real at equivalent energy/mass cost).

I think that Matt Strassler (currently a visiting scholar at Harvard University) does an excellent job here:

 http://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/



<<The term “virtual particle” is an endlessly confusing and confused subject for the layperson, and even for the non-expert scientist. I have read many books for laypeople (yes, I was a layperson once myself, and I remember, at the age of 16, reading about this stuff) and all of them talk about virtual particles and not one of them has ever made any sense to me. So I am going to try a different approach in explaining it to you.

The best way to approach this concept, I believe, is to forget you ever saw the word “particle” in the term. A virtual particle is not a particle at all. It refers precisely to a disturbance in a field that is not a particle. A particle is a nice, regular ripple in a field, one that can travel smoothly and effortlessly through space, like a clear tone of a bell moving through the air.  A “virtual particle”, generally, is a disturbance in a field that will never be found on its own, but instead is something that is caused by the presence of other particles, often of other fields.>>

ADDED (Feynman diagrams):

<<The language physicists use in describing this is the following: “The electron can turn into a virtual photon and a virtual electron, which then turn back into a real electron.” And they draw a Feynman diagram that looks like Figure 4. But what they really mean is what I have just described in the previous paragraph. The Feynman diagram is actually a calculational tool, not a picture of the physical phenomenon; if you want to calculate how big this effect is, you take that diagram , translate it into a mathematical expression according to Feynman’s rules, set to work for a little while with some paper and pen, and soon obtain the answer.>>

<<This is shown in Figure 7, and the corresponding Feynman diagram is shown in Figure 8.  This goes on and on, with a ripple in any field disturbing, to a greater or lesser degree, all of the fields with which it directly or even indirectly has an interaction.

Fig. 8: The Feynman diagram needed to calculate the process shown in Figure 7.
So we learn that particles are just not simple objects, and although I often naively describe them as simple ripples in a single field, that’s not exactly true.  Only in a world with no forces — with no interactions among particles at all — are particles merely ripples in a single field!  Sometimes these complications don’t matter, and we can ignore them.   But sometimes these complications are central, so we always have to remember they are there.>>

Title: Re: EM Drive Developments
Post by: aero on 09/12/2014 09:38 PM
@GoatGuy, frobnicat,

Your arguments illustrate that the operational principles of the EM drive satisfy Clark's third law - they are, "indistinguishable from magic". Your arguments do not advance our understanding of those principles. Others have taken the risk and dared to postulate principles but I know of none that are accepted. Go ahead, take the risk, postulate physics sufficiently advanced as to cast light on the difference between operation of the EM drive and magic.
Title: Re: EM Drive Developments
Post by: 93143 on 09/12/2014 09:55 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254645#msg1254645">Quote from: GoatGuy on 09/12/2014 07:28 PM</a>
I hope there will be a reply that answers this fundamental flaw.

A Mach-effect device is supposed to be interacting with the distant universe; that's inherent in the theoretical derivation.  (If I understand correctly, the Wheeler-Feynman stuff doesn't have to be assumed to get this result; Sciama's model and Woodward's application of it just have to do with local gravitational potential.)

Basically, your energy balance isn't complete until you've accounted for the device's interaction with the rest of the matter in its Hubble sphere, whatever form that interaction takes.  In other words, you're drawing the box too small.

Furthermore, without something to push on, you aren't just violating conservation of energy; you're violating conservation of momentum too.  The equations of mechanics don't work that way, and you can see this if you consider the fact that the kinetic "energy" of a single body is frame-dependent - only a momentum-conserving system exhibits Galilean invariance of kinetic energy changes due to interactions.  So really, using Newtonian mechanics to treat a Mach-effect thruster in isolation is nonsensical from the start.

...

I'm not sure how the Q-thruster is supposed to conserve energy; it looks like a ZPE device to me, but then I haven't studied it much...

Regarding the EM-Drive, I thought it was pretty well established that Shawyer's explanation implied a violation of conservation of momentum, and that thus if the drive worked it would be for some other reason.  Again, though, I haven't studied it much...

Title: Re: EM Drive Developments
Post by: frobnicat on 09/12/2014 10:57 PM
@dr Rodal,
Frankly I'm not qualified to argue about details of vacuum, so maybe I should rather shut my mouth about that  :P  But I will definitely read the link to Matt Srassler when time permits, thanks.

Actually my point in this former post of mine (from which I was excerpting) was that, as far as I know (which is not much in quantum physics, a little more in phenomenological astrophysics) vacuum is Lorentz invariant, and all attempts at putting intrinsic frames of reference of space/vacuum or aether back on the table failed experimentally so far (though there are theories...). It's important as it makes inescapable the "free energy" consequence of "pushing on the vacuum" : breaking momentum conservation (or exchanging net momentum with vacuum) is breaking energy conservation (or exchanging energy with vacuum), one can't go without the other, regardless of possible theories beyond very very well verified quantitative predictions of Newtonian mechanics at speeds<<c, please correct me if I'm wrong on that.

If there is indeed favorite intrinsic frames of reference or aether then yes, I see how it would be possible to push on that with much better efficiencies than with reaction propulsion, without breaking energy conservation (or pumping some from vacuum) but then the k factor would decrease as your absolute speed relative to this aether increase, and mission profiles are not the same. Also some "aether wind" effect should be observed in conjunction with earth rotation (orientation of the experiment relative to the stars). Unless the aether is anchored to nearest massive body (back to old aether problems...).

The point is, this free energy consequence is seldom put forward by, let's say, enthusiasts of space drives. As if maybe free (or cheap) momentum were deemed "more acceptable" than free (or cheap) energy that is so much connoted crackpot science. If it works at all for thrust and spaceships then so well, but please proponents, don't put the free energy generators under the rug as it is a consequence. It sounds sarcastic but I'm not, I'm not against the experiments or the experimenters, clearly I'm very sceptic about a "real" (useful) effect here but ready to be convinced when/if results can be reproduced by sceptics. It needs the sceptics to be convinced that it's worth to try reproduce the experiments. But there is no point in trying to hide the "free energy" consequences.

@aero
yes when Michelson and Morley experiment show the breaking of the rule of speed additivity, this is a result indistinguishable from magic. I'm not qualified and gifted enough to advance the principles at work, should the EMthrust prove to be real. Then maybe the k factor would be observed to decrease with speed in such a way not to break energy conservation or pump it from vacuum, but then don't expect the same mission profiles for spaceships. Or maybe the k factor is indeed free from v effects and, in all logic, we have free energy, even real possible free energy devices tomorrow if k approaches 1N/kW as hoped by proponents.
But we are not at the point where the effect is accepted so I feel no urge to fill the theoretical gap.
Again, I'm not against dedicated minds taking the risk, and quite supportive of inquiring the possible effect, if not by sending a million dollar probe at first, at least by providing means to try to reproduce it and investigate it phenomenologically (magnitude dependence on energy densities ? dependence on orientation relative to stars ? dependence on velocity/acceleration when freely moving ? ...) then we can discuss the theories on firmer ground.
But (again) I'm against a "what if it works" scenario that wont go to all the inescapable consequences, when the consequences are on firm ground that couldn't possibly be overtaken by the hypothesis (I don't see how the possibility to push on vacuum could change the observed fact that Ec=1/2mv² as far as practical mundane useful kinetic energy is concerned, how ?) : this is too reminiscent of bad SciFi. Fantasy is another realm but wont take us to the stars. Why wouldn't you want a nice free energy generator to power up your free momentum drive ?
Title: Re: EM Drive Developments
Post by: frobnicat on 09/12/2014 11:28 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254700#msg1254700">Quote from: 93143 on 09/12/2014 09:55 PM</a>
So really, using Newtonian mechanics to treat a Mach-effect thruster in isolation is nonsensical from the start.

Using Newtonian mechanics to treat the local useful consequences of such a thruster in not nonsensical, the fact that the energy balance would be conserved instantly within the cosmological horizon can be satisfactory for theorists, but as far as engineering goes this is indistinguishable from free energy and doesn't prevent to make accurate mission profiles with Newtonian mechanics or making real unlimited energy generators, assuming the effect is real, regardless of theories. Again, if the effect is real, then very well, we have good spaceships, and good energy generators, free energy, for all practical purpose.
Sorry to put forward my take on this GoatGuy, this was addressed to you.
 

Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 12:21 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254717#msg1254717">Quote from: frobnicat on 09/12/2014 10:57 PM</a>
....

@frobnicat, yes, I agree, as I posted before there are substantial problems with the proposed "out of the mainstream" explanations.   So, what I propose is that instead we discuss

A) my preference at the moment: alternative explanations for the experimental measurements, or if, you prefer,

B) we discuss in detail Dr. White's equations .   We could discuss the fact that, in the end, Dr. White does NOT actually use in his calculations the density of the (zero point) quantum vacuum, but instead he uses what he calls a "local quantum vacuum density" that is several orders of magnitude larger than the density of the zero-point quantum vacuum.  Those  in this forum that defend or battle the "zero point quantum vacuum" explanation may be defending or battling an un-existing explanation . 

So, how about discussing Dr. White's justification for the much higher value he uses for the "local density of the quantum vacuum" and what this implies ...?

Title: Re: EM Drive Developments
Post by: 93143 on 09/13/2014 12:39 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254721#msg1254721">Quote from: frobnicat on 09/12/2014 11:28 PM</a>
Again, if the effect is real, then very well, we have good spaceships, and good energy generators, free energy, for all practical purpose.

If the operation of the device is independent of its velocity (Woodward's equation sure looks like it is), and the efficiency in N/W gets high enough for practical application in an energy-generating device, yes, you could do that.  I have myself maintained in the past that this sort of technology could revolutionize far more than just space travel.

I have a half-formed idea involving the relativistic Doppler effect that I think might explain the apparent velocity independence of the M-E drive principle, in such a way that a "free-energy" device like what you're describing would essentially be a heat engine powered by the Big Bang.  But maybe I should shut up about it until I've had time to get into the theory a little more...

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254733#msg1254733">Quote from: Rodal on 09/13/2014 12:21 AM</a>
as I posted before there are substantial problems with the proposed "out of the mainstream" explanations.

Regarding the Wheeler-Feynman idea specifically, I'm not sure what you've stated constitutes an ironclad case against it.  For one thing, it seems to me that gravity and the weak force are two different things, and since we don't even have a theory that unifies them it strikes me as premature to claim that time-asymmetry in one necessarily implies time-asymmetry in the other (though I may be misunderstanding something).  For another, according to the Wikipedia page (no, I'm not an expert; can you tell?) on W-F absorber theory, there have been calculations that recover the Lamb shift without requiring self-energy.

I'm an engineer, not a physicist, but this sounds like an open question to me.

Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 12:50 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254736#msg1254736">Quote from: 93143 on 09/13/2014 12:39 AM</a>


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254733#msg1254733">Quote from: Rodal on 09/13/2014 12:21 AM</a>
as I posted before there are substantial problems with the proposed "out of the mainstream" explanations.

Regarding the Wheeler-Feynman idea specifically, I'm not sure what you've stated constitutes an ironclad case against it. 

Well, then you are stating your own theory, not Dr. Woodward's, because as per the video I posted, Dr. Woodward answered that his theory requires either the Wheeler-Feynman absorber theory (or even more unsupported by experiments, a constrained theory changing the type of differential equations (elliptic instead of hyperbolic  !!!!!)).

Also, you seem to be stating your own theory, not Dr. Woodward's, concerning the incompatibility with the Weak Force, because Dr. Woodward's also stated in that video that his interpretation for the inertia effect is a radiation interaction, and we know that the Weak Force interaction is paramount in a radiation interaction.

But a theory of Physics is more than just words we can discuss in this thread, you would have to replace Dr.  Woodward's theory with your own set of consistent equations...

Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 01:03 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254736#msg1254736">Quote from: 93143 on 09/13/2014 12:39 AM</a>
it strikes me as premature to claim that time-asymmetry in one necessarily implies time-asymmetry in the other (though I may be misunderstanding something).

It is not premature to claim that there is only one time and not two times.  There is not one time for gravitation and another time for the Weak Force, there is only one time in Dr. Woodward's theory.  When Dr. Woodward explains his inertia effect as a radiation interaction he is using the same time that he uses for gravitation in his General Relativity equations.


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254736#msg1254736">Quote from: 93143 on 09/13/2014 12:39 AM</a>
For another, according to the Wikipedia page (no, I'm not an expert; can you tell?) on W-F absorber theory, there have been calculations that recover the Lamb shift without requiring self-energy.

Yes, as you know anybody (even without being registered in Wikipedia) can anonymously write and change things in Wikipedia.  The alternative calculations that recover the Lamb Shift without requiring self-energy are not generally accepted, and have problems of their own.  I wrote a lot of the Wikipedia article on the Beta Distribution (  http://en.wikipedia.org/wiki/Beta_distribution ) (you can see my name associated with most graphs and in the Talk Page), I know what a headache is to deal with this issue by Wikipedia managers, who try to do their best  :)

Title: Re: EM Drive Developments
Post by: 93143 on 09/13/2014 01:05 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254738#msg1254738">Quote from: Rodal on 09/13/2014 12:50 AM</a>
Dr. Woodward's also stated in that video that his interpretation for the inertia effect is a radiation interaction, and we know that the Weak Force interaction is paramount in a radiation interaction.

I'm sorry; you've lost me.  What has the weak force got to do with the propagation of changes in a gravity field?

Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 01:08 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254743#msg1254743">Quote from: 93143 on 09/13/2014 01:05 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254738#msg1254738">Quote from: Rodal on 09/13/2014 12:50 AM</a>
Dr. Woodward's also stated in that video that his interpretation for the inertia effect is a radiation interaction, and we know that the Weak Force interaction is paramount in a radiation interaction.

I'm sorry; you've lost me.  What has the weak force got to do with the propagation of changes in a gravity field?

Have you actually listened to the video I posted of Dr. Woodward?  I'm quoting what Dr. Woodward stated.  Perhaps you should state that "Dr. Woodward lost you". Dr. Woodward himself says that it is radiation interaction.

Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 01:16 AM
Dr . Woodward answers the question with the following statement:

it is a radiation reaction interaction, presumably, that involves the Wheeler-Feynman ...
Title: Re: EM Drive Developments
Post by: 93143 on 09/13/2014 01:21 AM
No, it's the part where the weak force is involved that confuses me.  I have Woodward's book; he's talking about gravity waves.  Something about quadrupole radiation with the rest of the universe as part of the system.  And as far as I know there is no universally accepted theory that couples gravity with any of the other forces.

Perhaps you could explain a little, rather than just assuming I already know all this and am being deliberately obtuse?
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 01:33 AM
At the time that Wheeler and Feynman conceived their theory (late 1940's) not much was known about the Weak Force.  We are here 70 years later, with all kinds of experimental results including the Weak Force's arrow of time, and its role in radiation.

Yes, you are correct that we don't have a Unified theory of Gravitation and Quantum Gravity.  And yes, Dr. Woodward can have a theory that uses Wheeler Feynman absorber theory (although Feynman himself abandoned that theory) and ignore the Weak Force if he likes.    I would prefer to consider present theories that are compatible with present experimental knowledge, including the Weak Force, and that explain known phenomena in a more unified way than it was possible in the 1940's.
Title: Re: EM Drive Developments
Post by: 93143 on 09/13/2014 01:35 AM
Does the weak force have anything to do with gravity waves specifically?  Because that's what Woodward is talking about.  He's not talking about the Wheeler-Feynman theory in electrodynamics; he's repurposing the concept for gravity.
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 01:46 AM
Sorry, I don't understand this statement <<Does the weak force have anything to do with gravity waves specifically?  Because that's what Woodward is talking about.  He's not talking about the Wheeler-Feynman theory in electrodynamics; he's repurposing the concept for gravity.>>.

Please explain how this works: does Dr. Woodward end up with gravity waves that travel at infinite speed?
Title: Re: EM Drive Developments
Post by: 93143 on 09/13/2014 02:01 AM
Of course not.  The whole point of the advanced/retarded wave concept in W-F is that you can get instantaneous action at a distance without breaking causality; no momentum or energy or information need travel faster than c.
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 02:07 AM
 <<the advanced/retarded wave concept in W-F is that you can get instantaneous action at a distance without breaking causality>>

We disagree:

instantaneous action at a distance means an infinite speed

and yes, Wheeler-Feynman absorber theory is well-known to break causality.  Both Wheeler and Feynman admitted this.  Feynman wrote about this in at least one of his books. 

Now, 70 years later, after Feynman dropped the W-F theory long ago, we have at least 3 arrows of time:

1) The cosmological arrow of time: from the order of the Big Bang, through Inflation through Dark Energy accelerating expansion (this last one unknown at the time of W-F).

2) The 2nd law of Thermodynamics arrow of time in the macro world we inhabit.

3) The Weak Force arrow of time at the Quantum Mechanics level (not well understood at the time of W-F theory).
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 02:21 AM
<< I have Woodward's book; he's talking about gravity waves.  Something about quadrupole radiation with the rest of the universe as part of the system.>>

I don't have any of Dr. Woodward's books.   I only read some of his papers.  My statement concerning radiation was entirely based on his video.  Thank you for explaining that he meant quadrupole radiation. Therefore what he meant was the radiation of the gravity waves, and he didn't mean anything to do with actual particle radiation  --therefore nothing to with the Weak Force in that sense, I agree.

Still I make my argument regarding the three arrows of time, and what we have learnt during the last 70 years since W-F, Dark-Energy accelerating expansion involvement for the Cosmological arrow of time and the Weak Force for the Quantum Mechanics arrow of time.
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 02:32 AM
You can disregard the Quantum Mechanics (Weak Force) arrow of time, and the 2nd law of Thermodynamics arrow of time (both at your own peril), concerning a theory of inertia and gravitation.  I would rather not disregard them. 

But I don't understand how you or Dr. Woodward can disregard the Cosmological arrow of time.

And it is strange to consider a General Relativity theory where one divorces completely from the Quantum Mechanics arrow of time (the Weak Force), but postulates that gravitational waves travel effectively with infinite speed, as with "action at a distance" (a concept only known in Quantum Mechanics entanglement).
Title: Re: EM Drive Developments
Post by: cuddihy on 09/13/2014 02:33 AM
Goat Guy: no page of calculations are required for a prima facie rejection of the premise.

Any scheme that requires mass-energy input to the object to equal the change in the object(s) mass-energy is by definition a normal rocket, not 'propellantless'.

'Propellantless', whether Woodward or EM or whatever *assumes* less mass-energy required to be input to the rocket than the rocket gains during this process. Period.
So argue the premise is rediculous all you want. But the calculation of difference between input and change doesn't add anything.
Title: Re: EM Drive Developments
Post by: 93143 on 09/13/2014 02:41 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254762#msg1254762">Quote from: Rodal on 09/13/2014 02:07 AM</a>
instantaneous action at a distance means an infinite speed

Are you sure you know what Wheeler-Feynman absorber theory actually says?  'Cause I was pretty sure I understood the gist of it, and what you've said here is wrong according to my understanding.  Nothing in the theory travels faster than c, and that remains true in Woodward's gravinertial version.

Quote
Still I make my argument regarding the three arrows of time

I don't find this a strong argument.  The only one of those three that seems potentially relevant is the cosmological one, but it's a bit circular (unless I've misunderstood it) and doesn't seem to bear on the nature of fundamental physical interactions.

Basically, just because some things are time-asymmetric doesn't mean all things are.  You yourself stated that the weak force is the only one of the four forces that seems to be, which as far as I can tell leaves the door pretty wide open for what Woodward is describing...

I'm not saying he's right.  But I don't think you've made much of a case for saying he must necessarily be wrong.

Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 02:52 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254772#msg1254772">Quote from: 93143 on 09/13/2014 02:41 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254762#msg1254762">Quote from: Rodal on 09/13/2014 02:07 AM</a>
instantaneous action at a distance means an infinite speed

Are you sure you know what Wheeler-Feynman absorber theory actually says?  'Cause I was pretty sure I understood the gist of it, and what you've said here is wrong according to my understanding.  Nothing in the theory travels faster than c, and that remains true in Woodward's gravinertial version.


The statement is absolutely correct on the first count.  Instantaneous action at a distance means an INFINITE speed, in any theory, not just W-F theory.  The only proviso you could make would be to involve Quantum Mechanics here all of a sudden and claim that instantaneous is restricted to the Planck time  :)

Title: Re: EM Drive Developments
Post by: 93143 on 09/13/2014 03:00 AM
I was using the phrase in the context of W-F theory, where (if I'm not greatly mistaken) it means something other than what it seems to mean on its face.

As far as I can tell, the idea is basically that a particle that does something feels the reaction from other particles instantaneously, but the other particles actually react at time t0+r/c.  This is where the reversed-time waves come in - the initial action resulted in a normal retarded wave, which propagated at c, and the other particles on receiving this wave produced an advanced wave in response which traveled back in time to converge at the point of initial action.

In the context of M-E, it would mean that the thruster feels the effect of the distant matter reacting to its operation instantaneously, but the distant matter doesn't actually react for billions of years.
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 03:03 AM
I have not seen Dr. Woodward's "re-purposing" of W-F for gravitational waves.  If Dr. Woodward's formulation results in a causal gravitational wave, then it canNOT be "instantaneous action at a distance".  But that is NOT what Dr. Woodward answered in the video. 

Do you claim that Dr. Woodward misspoke in the video? Or that Dr. Woodward meant that instantaneous action is not an infinite speed? How long a period of time is instantaneous according to Dr. Woodward?
Title: Re: EM Drive Developments
Post by: aceshigh on 09/13/2014 03:05 AM
I think we are only missing Dr Woodward and Dr White themselves in this topic right now :D
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 03:06 AM
<<the thruster feels the effect of the distant matter reacting to its operation instantaneously>>

Well instantaneous means an Infinite speed.  How does the thruster "feel" the effect of distant matter instantaneously?  Does the thruster have a special means of feeling that is traveling through wormholes and not through spacetime?
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 03:09 AM
Does the thruster have a special means of feeling distant matter that is traveling through ANOTHER DIMENSION, one of the infinitesimally small extra dimensions of string theory and it is wormholing through that extra dimension and hence avoiding normal spacetime?
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 03:11 AM
Actually, one of Dr. White's papers invoked a string theory manifold with 1 extra dimension (3+1), having 4 space dimensions...But I haven't seen anything by Dr. Woodward invoking extra dimensions...
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 03:16 AM
The "Chung-Freese" metric with 3+1 dimensions.... NO experimental evidence whatsoever for that.  But you are free to consider it if you like.  I would rather consider a Cosmological arrow of time myself, I think that there is much more evidence for that...
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 03:22 AM
And to be fair to Dr. White, he only invoked the Chung-Freese 3+1 metric to see how far he could push the warp field drive concept.  I don't fault him for that, it was an interesting exercise. 

Dr. White did not invoke the Chung-Freese 3+1 to justify action at a distance. 
Title: Re: EM Drive Developments
Post by: 93143 on 09/13/2014 03:36 AM
Perhaps you should slow down and read my whole post a little more carefully.

There is no instantaneous communication.  There is an instantaneous reaction that results from communication forward and then backward in time, at c.  The distant matter does not feel the interaction at the same time the thruster does.

[NB for anyone reading this:  this is not the result Woodward derived.  It is an explanation he brought in afterward to make sense of the implications of his result, and does not have to be accepted in order to take his experimentation or even his Mach-effect equation seriously.]
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 03:45 AM
OK, this was an enjoyable discussion.

You admit that <<There is an instantaneous reaction that results from communication forward and then backward in time>>

There are two things here that bothered me greatly:  1) instantaneous reaction and 2) communication backwards in time.

I would rather consider other alternatives, which respect the arrow of time, and where there is no instantaneous reaction.  I have much more of a problem with  " communication backwards in time" than with the information traveling through an extra dimension in the Chung-Freese metric.   You know, there are string theories (one of them proposed by Professor Randall at Harvard (http://en.wikipedia.org/wiki/Randall%E2%80%93Sundrum_model )) that support the idea of gravitation being the only force that escapes our 3-D Universe -that's why gravity is so weak compared to the other forces-. 

I think that Dr. Woodward also is not 100% comfortable: he smiled and said "that's the obvious question to ask" and he said "presumably....".   Presumably means that he is not 100% comfortable with this.   And he didn't give only one alternative, he gave two:  the Wheeler-Freeman was one, and constraining the equation to become elliptic instead of hyperbolic was another one.  To me it looks like he was not very certain of what is the answer...

Let's continue this later  :)
Title: Re: EM Drive Developments
Post by: birchoff on 09/13/2014 01:04 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254494#msg1254494">Quote from: Star-Drive on 09/12/2014 12:58 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254413#msg1254413">Quote from: Rodal on 09/12/2014 01:59 AM</a>
John (Fornaro) and Paul (March),

The experimental results and possible explanations are not trivial, addressing and studying them will take patience and time.  There are subtle issues involved because of the extremely small forces being measured. 

There is no hurry. 

I think that we have a great line of communications !.  Let's keep it going. :D


To Infinity and Beyond (or to wherever we can get with the propulsion we have)

Jose' Rodal

Look up at the stars. Try to make sense of what you see. Be curious.

Jose':

I've been involved in testing Dr. Harold Sonny White's Q-Thruster approach to exotic propulsion for seven plus years now, and Dr. James F. Woodward's Mach-Effect (M-E) work for sixteen years.  (I started down this road in March of 1998 while working for Lockheed-Martin at JSC working as an electrical engineer on the NASA Space Shuttle program.)  I summarize my M-E AKA Woodward Effect research in three STAIF papers published in 2004, 2006 and 2007.  I know Dr. Woodward's body of M-E work extensively having been to his lab at CSUF a number of times now, and IMO Woodward has been seeing real forces in his M-E Thruster (MET) experiments for years. 

These latest experimental results on the Q-thruster is just trying to take Jim's work one step further by attempting to quantize the gravitational field in a manner consistent with Quantum Mechanics (QM), Plasma Physics and General Relativity Theory (GRT).  In other words if you are not already familiar with this body of work that Dr. Woodward started in 1982, you need to perform due diligence in reading several of the papers that Dr. Woodward, Dr. White and I have written over this time period.  Primarily I'm just the electrical engineer turned experimental physicist that is trying to make this exotic propulsion business work, for without something like it, humanity is doomed to stay inside the asteroid belt for the foreseeable future.  In the meantime if you can't find the papers in question e-mail me a note and I'll be glad to get them to you.

Best,

@PaulMarch

Not sure if you will be able to answer this or not but, are there any plans for EagleWorks to carry out tests on Woodward's M-E devices?

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/13/2014 01:21 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254645#msg1254645">Quote from: GoatGuy on 09/12/2014 07:28 PM</a>
Previous posts at NBF (of mine) have been pasted here;  so far, I see little love for the position(s) I've taken.

Hah! 

Most of the objections were issues of writing style, but I wouldn't worry about it.  I have "stylistic" issues myself.  Check my deleted post history for details.

Still, from my armchair, the propellantless propulsion "team" gives every impression of being honestly convinced that they have discovered a natural phenomenon which they hope could be harnessed for HSF.

They can barely discern the effect from background noise, and have yet to float the device over the conference room table, in front of investors.  From a stylistic standpoint, I object strenuously to the culturally optimistic projections of missions to Saturn and so forth, particularly when HSF in the immediate neighboorhood is so primitive.

They assert that NASA decisionmakers have to be sold on the sizzle of this speculative future if they are to even get small amounts of money for their research.  This just irks me to think that the folks at NASA keep forgetting the potential for a propellantless drive flight system.

They do not answer questions about what does the device push on.  As I said above,
one could say they have ansered the question about what their devices instantaneously push upon, if and only if any answer were acceptable without experimental proof or without requiring the "answer" to reconcile other theoretical incompatabilities.

So.... many thanks for your algebraic explanation.  I will be sending you a bill for the two or three sheets of used paper that I must now use in order to print this out for my education.

Hope ya don't mind.

Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 02:14 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254858#msg1254858">Quote from: birchoff on 09/13/2014 01:04 PM</a>

@PaulMarch

Not sure if you will be able to answer this or not but, are there any plans for EagleWorks to carry out tests on Woodward's M-E devices?

@birchoff

See this paper by Paul March, Fig.7 and Fig.8, p.1330:
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=31119.0;attach=496011

FIGURE 7. Woodward’s Mach-2MHz MLT Test Article, vxB core & March’s Test Stand.
FIGURE 8. Mach-2MHz MLT Test Results - Predicted Thrust is 1.3 / 5.0 Milligram-Force.

and this paper by Dr. White, slide 40:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf

It appears from this that Paul March's/Dr.Woodward's device is the one tested in the 2005 campaign shown by Dr. White giving:

Thrust ~ 3 mN

Specific Force ~ 0.3 N/kW



Title: Re: EM Drive Developments
Post by: GoatGuy on 09/13/2014 02:16 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254676#msg1254676">Quote from: frobnicat on 09/12/2014 08:48 PM</a>
A few caveats :

1. Your calculations are Newtonian mechanics, when approaching c speeds or Thrust/Power ratios below 1/c its no longer valid...

2. Ok so we are breaking energy conservation, great : Noether's theorem show this implies reality not to be time invariant. Hard to swallow much much below cosmological timescales.

3. Ok so energy is conserved but the acquired energy is pumped from vacuum, not free energy but rel cheap energy, great : quoting myself  "tap into vacuum zero-point energy, which would no longer be zero-point...

4. Penultimate point : if the k factor somehow decays with acquired speed ...  it's really difficult to see what would make the system "remember" this particular initial reference frame

5. Last point : the k=0.4 N/kW figure used for the mission profiles implies possible breakeven starting at speeds of 1/k=2.5km/s relative to a fixed frame. ... I'd like to see the experiment done on a freely rotating arm, in an otherwise rotationally symmetric setting around the axis.

Replies...

(1) - Yes, agreed.  However, at the velocities contemplated even to get to the next star, we're way, way below relativistic velocities that require changing the simple math of Newton.  Even doing a "fly thru" to alpha Centauri using the same ship that was proposed to make it to Saturn in 289 days would only be going 8.9% of c in 98 elapsed years.

(2) - We probably agree, but my ignorance of Noether's Theorem is a hindrance.

(3) - I guess this is where I get stuck: if there is some tinderbox of really cheap energy that these things are tapping into, it just kind of breaks down Physics. Even Casimir forces don't break physics: they imply measurable attractive/repulsive forces on micron-to-angstrom scales, between various electromagnetically active materials, and they have been measured to not be much different than envisioned.  Moreover, (sadly for those wishing to employ Casimir force(s) for making free-energy devices), like electromagnetic and gravitational fields, the circular integration of force over any closed path in a Casimir field is exactly zero

(4) - Indeed... the initial reference-frame memory is required if total system energy is to be conserved.  It is the only way that the magical caveat ("system cannot exceed ΔV=2/k ...") can be maintained.  Δ means "change", which means "from initial state".  Hence... yep, we agree.

Personally, I really hope that the effect is real, that it doesn't have "memory issues", that it can be scaled with higher Q devices or higher dielectric piezoelectric quality factors, to far higher 'k' values than the present 5 to 22 µN/W reported levels. The 1/k for these (200,000 m/s to 45,000 m/s respectively) are far too high to employ here on Planet Dirt as alternative energy force generators.  Unobtanium.  But somewhere north of 2 mN/W, the critical 1/k velocity of 500 m/s becomes entirely attainable for large rotors;  COP of 5+ can be imagined as manufacturable, with moderately exotic materials.

GoatGuy

Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 02:29 PM
frobnicat <<3. Ok so energy is conserved but the acquired energy is pumped from vacuum, not free energy but rel cheap energy, great : quoting myself  "tap into vacuum zero-point energy, which would no longer be zero-point... >>

GoatGuy <<(3) - I guess this is where I get stuck: >>

How about discussing the actual equations that Dr. White uses to calculate the thrust?

Dr. White uses a "local quantum vacuum density" that is several orders of magnitude larger than the zero-point quantum vacuum density.

(Not that I agree with the physical model they propose, see my previous posts; but it would be interesting to discuss the actual equations he uses instead)
Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/13/2014 02:39 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254676#msg1254676">Quote from: frobnicat on 09/12/2014 08:48 PM</a>
... the possibilities of delivering grand pianos to Saturn moons for enthusiasts.

Whoah there, kemosabe.  I've never promised anybody a piano.  I only promise ponies. 

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/13/2014 02:39 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254693#msg1254693">Quote from: aero on 09/12/2014 09:38 PM</a>
@GoatGuy, frobnicat,

Your arguments illustrate that the operational principles of the EM drive satisfy Clark's third law - they are, "indistinguishable from magic". Your arguments do not advance our understanding of those principles. Others have taken the risk and dared to postulate principles but I know of none that are accepted. Go ahead, take the risk, postulate physics sufficiently advanced as to cast light on the difference between operation of the EM drive and magic.

Your assertion that the arguments above illustrate that the devices are "indistinguishable from magic", is itself only an assertion.

For purposes of discussion, let us assume that the devices have been theoretically dis-proven to be "indistinguishable from magic".  If the "dis-proof" has been proven, then indeed that does in fact advance our understanding, because we would no longer have to expend time talent and treasure working on a device that will never perform as hoped.

To put it another way, those two avatars are not claiming to be able to build a device which would send a 90 ton spacecracft  to Saturn and return a significant fractional mass of that spacecraft to Earth 788 days later.

The onus of proof is on those who make the extraordinary claim, not on those who find mathematical and theoretical objections to those claims.

Just sayin'.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/13/2014 02:40 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254700#msg1254700">Quote from: 93143 on 09/12/2014 09:55 PM</a>
Regarding the EM-Drive, I thought it was pretty well established that Shawyer's explanation implied a violation of conservation of momentum, and that thus if the drive worked it would be for some other reason.

That is my recollection as well.  Over on the far too long "Propellantless Propulsion" thread, there was a seemingly valid, to me, disputation of Shawyer's work.

Quote
Basically, your energy balance isn't complete until you've accounted for the device's interaction with the rest of the matter in its Hubble sphere, whatever form that interaction takes.  In other words, you're drawing the box too small.

Furthermore, without something to push on, you aren't just violating conservation of energy; you're violating conservation of momentum too.

I don't care for the various "free energy" claims either.  How do these devices push and pull on all the matter in their Hubble sphere, instantaneously, and in a controlled direction, subject to the whims of the spaceship's driver?

While I am interested in the experimental setup, I am also interested in the theory.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/13/2014 02:40 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254717#msg1254717">Quote from: frobnicat on 09/12/2014 10:57 PM</a>
...all attempts at putting intrinsic frames of reference of space/vacuum or aether back on the table failed experimentally so far ...

I keep on believing in the ether, because it would explain so much, including inertia.

But that's my work, no excuses, no blame to another. 

Quote
I'm against a "what if it works" scenario that won't go to all the inescapable consequences, when the consequences are on firm ground that couldn't possibly be overtaken by the hypothesis.

Bingo.

You do a pretty damn good job with English there, buddy.  What is your native tongue?

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/13/2014 02:40 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254748#msg1254748">Quote from: Rodal on 09/13/2014 01:16 AM</a>
Dr . Woodward answers the question with the following statement:

it is a radiation reaction interaction, presumably, that involves the Wheeler-Feynman ...

I really appreciate your analysis of the experimental setup.  However, Mr. Woodward does not answer any questions at all by saying "presumably".

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/13/2014 02:41 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254760#msg1254760">Quote from: 93143 on 09/13/2014 02:01 AM</a>
Of course not.  The whole point of the advanced/retarded wave concept in W-F is that you can get instantaneous action at a distance without breaking causality; no momentum or energy or information need travel faster than c.

I objected to the advanced/retarded wave concept here:


Woodward brought up [advanced/retarded wave concept] in his book.  (http://forum.nasaspaceflight.com/index.php?topic=31037.msg1074698#msg1074698)

Cuddihy attempts to explain why my objection is incorrect, but I think he misses my point:

"somehow predicting my whimsical left and right turns" is not correct. (http://forum.nasaspaceflight.com/index.php?topic=31037.msg1075738#msg1075738)

If I am driving a spacecraft which uses the advanced/retarded wave concept as a key principle of its operation, somehow, as I go on a joyride thru the galaxy, those gravitational waves that I'm depending on for propulsion change direction instantaneously with every whimsical turn of my hand on the steering wheel of my spaceship. 

Makes no sense to me.

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254768#msg1254768">Quote from: Rodal on 09/13/2014 02:32 AM</a>
And it is strange to consider a General Relativity theory where one divorces completely from the Quantum Mechanics arrow of time (the Weak Force), but postulates that gravitational waves travel effectively with infinite speed, as with "action at a distance" (a concept only known in Quantum Mechanics entanglement).

Yeah it is.

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254778#msg1254778">Quote from: Rodal on 09/13/2014 03:03 AM</a>
Do you [93143] claim that Dr. Woodward misspoke in the video? Or that Dr. Woodward meant that instantaneous action is not an infinite speed? How long a period of time is instantaneous according to Dr. Woodward?

I dunno, but that video is not the body of Mr. Woodward's work.

Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 02:47 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254886#msg1254886">Quote from: JohnFornaro on 09/13/2014 02:40 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254748#msg1254748">Quote from: Rodal on 09/13/2014 01:16 AM</a>
Dr . Woodward answers the question with the following statement:

it is a radiation reaction interaction, presumably, that involves the Wheeler-Feynman ...

 Mr. Woodward does not answer any questions at all by saying "presumably".

Yes Dr. Woodward clearly said "presumably" (in the video I referenced)  :).  And Dr. Woodward answered only one question -not several questions- in that video.

Please listen to Dr. Woodward's answer again, and if you don't agree he said "presumably" please post the answer you hear he gave: (
[ http://www.youtube.com/watch?v=hn8hqX9JBOE#t=2468 ]
where I have on purpose timed it to when the question is asked, otherwise advance to the end of the presentation at 41:08 minutes (2468 sec))

Title: Re: EM Drive Developments
Post by: GoatGuy on 09/13/2014 02:48 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254863#msg1254863">Quote from: JohnFornaro on 09/13/2014 01:21 PM</a>
1. Most of the objections were issues of writing style...

2. HSF

3. They can barely discern the effect from background noise (and so) I object strenuously to the culturally optimistic projections of missions to Saturn and so forth...

4. They assert that NASA decisionmakers have to be sold on the sizzle...

5. They do not answer questions about what does the device push on.

6. So.... I will be sending you a bill for the two or three sheets of used paper...

Replies:

(1) Thank the Diety for that.  My style won't likely change, so I can rest satisfied that it'll pique some people's pin-feathers.

(2) HSF.  HSF?  Ah... Human Space Flight.  See... I'm a newbie.

(3) Some experimenters presented a table showing 5.5 to over 21 micronewtons per watt (at under 3 watts input).  Won't float the thruster over the board table, but still getting closer to the levels needed to really "invest deep".  Now, missions to Saturn in 286 days?  Yes, those are galling.

(4) Sizzle, schmizzle. The rather conservative Make-in-Missouri types of NASA want to see a large enough effect with a criteria somewhere around 1 mN/W to challenge existing methods such as Xenon ion drives, which achieve a similar thrust, without requiring the "magic" of pulling on the Universe's Zero-point Wind, etc.  They don't need sizzle.  They need 1 mN/W with the upside potential to make thrust substantially greater than this, theoretically.

(5) What is being deflected is the sense I get: if it is the Universe itself, then that's a pretty startling idea, but not a particularly outrageous one.  Most people don't even give it consideration, but when you or I hop in a car and accelerate onto the highway, we are pushing against the whole Earth, which ever so infintessimally, is accelerated in the opposite direction.  The whole system is MV invariant. 

The reason why I say deflected instead of pushed against is this:  if we are pushing against something (like the Earth, for our car situation), then the amount of energy expended depends on both the initial velocity of the car relative to the pusher-plate, and the change-in-velocity (integration of acceleration) of the vehicle, times its mass.

Or, to put it a bit more succinctly:

P = maV   (mass times acceleration times velocity)...

the higher the V, the more power P is required.  Empirically, in cars this makes sense ... at low velocities, the power of the engine can produce (through gearing) high accelerations.  At high velocities, it cannot.  No magic, just physics.

OK, that being what it is, then if we are pushing against the Universe, then it must be relative to our velocity compared to the universe's velocity frame.  There is no way around that one, I'm afraid.  However, as I recall an analogy trotted forth in another forum about just this, the poster said,

Quote
But Goat, the Mach Woodward is deflecting the intertial energy of the Universe, not unlike how a sailboat's sails are harvesting energy from the passing wind

This is an intriguing idea - because at low velocities (non-relativistic, to be sure), the very fast, very tenuous "inertial wind" could be deflected to produce tangible force, without seeming to diminish as our test vehicle is accelerated to higher velocities.  It is hugely attractive, even if there is little-to-no theory to support the idea.  It also might imply that there wouldn't be directionality anisotropy, as the inertial wind could be directly related to the expansion of SpaceTime itself, which we now know to be ongoing, and accelerating itself.  Energy from latching onto the expansion of the Universe.  Wow.  That'd be a big supply!

(6) OK - I'm glad you used used paper to paper these ideas ideologically.  (Sorry, I couldn't pass the opportunity to pen a sentence that employs double-words in succession, homophones with different meaning.)

GoatGuy

Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 03:33 PM
Concerning a critique of Dr. White's QVPT model, besides addressing the actual equations and justification that Dr. White used (including the fact that Dr. White uses a "local quantum vacuum density" several orders of magnitude larger than the zero point quantum vacuum density), a fair analysis would address Dr. White's attempt at analysis of conservation issues. 

(For example the "QVPT Conservation Issues" slide where Dr. White wrote: “Compressed” vacuum serves as potential energy source (like a compressed spring, hence “negative”); “expanding” the vacuum does work on the system which has the net effect of increasing system box’s kinetic energy, etc. etc.).

Title: Re: EM Drive Developments
Post by: frobnicat on 09/13/2014 04:19 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254874#msg1254874">Quote from: GoatGuy on 09/13/2014 02:16 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254676#msg1254676">Quote from: frobnicat on 09/12/2014 08:48 PM</a>

2. Ok so we are breaking energy conservation, great : Noether's theorem show this implies reality not to be time invariant. Hard to swallow much much below cosmological timescales.

(2) - We probably agree, but my ignorance of Noether's Theorem is a hindrance.

If you are fighting on the energy conservation ground this is a chief weapon ! Specifically you might be interested in the following link that explains how energy can be NOT conserved on cosmological scales : http://motls.blogspot.fr/2010/08/why-and-how-energy-is-not-conserved-in.html (http://motls.blogspot.fr/2010/08/why-and-how-energy-is-not-conserved-in.html). Don't expect clarifications from me as most "details" are beyond my physics. Bottom line of consequences : yes energy conservation can be considered broken at cosmological scales when space is not asymptotically flat at large distances (but "energy" is by itself an ill-defined concept in this setting), no it's not a practical way to produce energy for free (see comments)

Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 04:42 PM
<< we are breaking energy conservation, great : Noether's theorem >>
 <<We probably agree, but my ignorance of Noether's Theorem is a hindrance.>>

Noether's theorem applies to a postulated Lagrangian, if the Lagrangian that was assumed is an incorrect model of physical reality (because it ignores important physical terms, or because it contains mathematical terms that are not a proper model of reality), Noether's theorem cannot correct this error, as Noether's theorem will  not produce a conservation law in accordance with reality.  (Garbage IN, Garbage  OUT applies.  "IN" is the assumed Lagrangian, "OUT" is the conservation law by Noether's theorem ..)

You should ask yourself: were all the relevant energy terms properly defined and included in the assumed Lagrangian?

Noether's theorem doesn't know anything concerning whether the assumed Lagrangian is a proper model of reality...
Title: Re: EM Drive Developments
Post by: Star-Drive on 09/13/2014 05:05 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254569#msg1254569">Quote from: Rodal on 09/12/2014 03:49 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254494#msg1254494">Quote from: Star-Drive on 09/12/2014 12:58 PM</a>
Jose':

I've been involved in testing Dr. Harold Sonny White's Q-Thruster approach to exotic propulsion for seven plus years now, and Dr. James F. Woodward's Mach-Effect (M-E) work for sixteen years. .....
Paul,

Thank you for pointing this out.  I have read with interest several of Dr. Woodward, and Dr. White's papers, including some of your own papers.  It is admirable, in  a sense, to have people willing to pursue research avenues that are not most popular, or commonly accepted.  Concerning Dr. Woodward's, theory, to cut to the chase, as Dr. Woodward himself accepts with a smile in the following presentation (
[ http://www.youtube.com/watch?v=hn8hqX9JBOE#t=2468 ]
where I have on purpose timed it to when the question is asked, otherwise advance to the end of the presentation at 41:08 minutes (2468 sec)) the obvious question to pose to Dr. Woodward is:

If your interpretation of Mach's principle is that inertia is a gravitational reaction from the rest of the Universe (no matter how distant from your center of mass) how come that reaction takes place INSTANTLY ?

In other words, in Dr. Woodward's theory, the propagation of this gravitational reaction responsible for inertia, has INFINITE speed, which is problematic in a Theory of Relativity (where we usually associate gravitational waves to travel at the speed of light).

Dr. Woodward answers with a smile, that "presumably" it is a radiation reaction attributable to Wheeler–Feynman absorber theory.  With his smile and frank facial expression he acknowledges that this is, let's say... problematic?

Because we know that:

A) The Wheeler–Feynman absorber theory assumes that the solutions of the electromagnetic field equations must be invariant under time-reversal symmetry, there is no distinction between past and future.

B)  It therefore assumes that elementary particles are not self-interacting. This is a big drawback of this theory. Indeed, as demonstrated by Hans Bethe, the Lamb shift necessitated a self-energy term to be explained. Feynman and Bethe had an intense discussion over that issue and eventually Feynman himself stated that self-interaction is needed to correctly account for this effect.

C) Wheeler and Feynman conceived of this theory before the Weak Force was understood as it is nowadays.  It is known that the Weak Force implies time-symmetry breaking and gives an arrow of time.  Hence the Weak Force is incompatible with the  Wheeler–Feynman absorber theory, in this sense.

I think that it was wise that you, Dr. White, et.al., decided that <<This paper will not address the physics of the quantum vacuum plasma thruster (QVPT), but instead will describe the recent test campaign>> (Abstract of "Anomalous Thrust Production..." paper).

In that vein, I think it would be best to discuss the experiments without addressing any controversial physical explanation for the time being.


Jose':

"I think that it was wise that you, Dr. White, et.al., decided that <<This paper will not address the physics of the quantum vacuum plasma thruster (QVPT), but instead will describe the recent test campaign>> (Abstract of "Anomalous Thrust Production..." paper).

In that vein, I think it would be best to discuss the experiments without addressing any controversial physical explanation for the time being."

Agreed but it appears others on this forum still want to go down other rabbit trails in pursuit of the holy grail as the additional four pages of posts on the topic since I last looked will attest. :)  However I will point out that Dr. Woodward's M-E conjecture does not need instantaneous Wheeler/Feynman radiation reaction forces or John Wheeler's elliptical constraint equations equivalent of same to allow the M-E conjecture to work as Jim proposes.  It just needs Mach's principle to be an integral part of Einstein's General Relativity Theory (GRT) and that the cosmological gravitational field energy density phi is equal to c^2 in a spatially flat universe.  Woodward has made a very strong case for just these assertions in his published journal papers from 1995 and on, in his ongoing M-E e-mail group, and especially in his 2013 "Making Starships and Stargates" book.  In other words if Einstein's GRT and the original Einstein equivalence principle holds, Mach-Effects are already part of these theoretical monuments if you know where to look for them. 

As to the other theoretical issues you and others have raised in this thread, we probably won't find the final answers to these enigmas until QM, GRT and the Standard Model are seamlessly integrated into a theory of everything (ToE).  (I know, I know, the answer is "42" :) )  Along this path however, I might suggest you consider that QM's supposed "greatest mistake" in calculating the vacuum energy density, (See: http://math.ucr.edu/home/baez/vacuum.html ), isn't a mistake after all, and consider the idea that ALL elementary particles like the electron are in fact 5+D vacuum energy rarefaction vortices like a tornado being balanced and maintained by electrostatic and gravitational forces per Woodward's ADM conjecture.  Past that it really gets strange and removed from experimental facts, so back to the lab work.

BTW, I'm a little late is saying this, but tell Goat Guy that he needs to perform his energy conservation analysis in the 4D GRT formalism and not the flat space-time Newtonian version he's been using to date when performing M-E or Q-Thruster based momentum and energy conservation calculations.  Woodward's 2004 M-E derivation paper's appendix A can show what's needed here.

As for White's Q-Thrusters, energy & momentum conservation is observed by the fact that the vacuum derived propellant has an energy equivalent mass that does have a velocity less than c.  And just like the standard rocket equation, your rocket's maximum obtainable velocity is dependent on the maximum exhaust velocity of the Q-Thruster that is driven by all its local and perhaps gravitational field input energies.  Our current model for same indicates that these vacuum e/p pair like propellant velocities should be in the range of 10,000-to-10,000,000 m/s for the geometries and input power levels we've looked at to date, but of course only if our Q-Thruster model Excel sheet is correct. 

PS:  A Hall thruster's input power to thrust efficiency or specific thrust is around 0.05 N/kWe using today's commercially available thrusters.  Air breathing jet engines can have thrust efficiencies of up to ~75 N/kWe at take off, so assuming a 0.40N/kWe for our Copernicus Orbital calculations is not way out on a limb, and in fact is representative of the performance of my first two Mach-Lorentz Thrusters (MLT) that I built in 2003 and 2004 and reported on in my STAIF-2006 paper.

Now to pay the bills...

Best,

Title: Re: EM Drive Developments
Post by: frobnicat on 09/13/2014 05:13 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254877#msg1254877">Quote from: Rodal on 09/13/2014 02:29 PM</a>
frobnicat <<3. Ok so energy is conserved but the acquired energy is pumped from vacuum, not free energy but rel cheap energy, great : quoting myself  "tap into vacuum zero-point energy, which would no longer be zero-point... >>

GoatGuy <<(3) - I guess this is where I get stuck: >>

How about discussing the actual equations that Dr. White uses to calculate the thrust?

Dr. White uses a "local quantum vacuum density" that is several orders of magnitude larger than the zero-point quantum vacuum density.

(Not that I agree with the physical model they propose, see my previous posts; but it would be interesting to discuss the actual equations he uses instead)

As I said, my understanding is limited. While I feel confident I can derive some practical consequences of exotic physics, when given phenomenological effects of said exotica (like for instance thrust/power>1/c without expelled reaction mass), as only an engineer by formation I shouldn't feel qualified and shouldn't have the time to dive into the exotic theories by themselves, did too much already. But I will read with great interest, in a state of trance, the ongoing theoretical speculations.

Can't resist. Just to be clear : if some net energy can be extracted from vacuum then something about vacuum is not understood and some other theories are needed. But I don't see how a higher density makes any difference :  the "problem" from my limited pov is to be able to get from vacuum any useful net energy or net thrust at all, however small. Why Dr White needs this higher density vacuum, to reconcile quantitatively with claimed magnitudes ?

Still willing to contribute, if possible, about experimental setup and possible classical explanations of the results.

@John : I'm French, and writing meaningful English is a daily struggle. Better you don't hear me speak English. Just like with advanced physics, I'm just pretending I can do it  ::)

Title: Re: EM Drive Developments
Post by: RotoSequence on 09/13/2014 07:23 PM
To get a... well, obvious question out of the way, if the effect is real, and is predicted to scale up, why not build a 33 kilowatt device, place it on an old fashioned weighing scale, and wow the world with a whole pound of thrust?
Title: Re: EM Drive Developments
Post by: ThinkerX on 09/13/2014 11:20 PM
I am a fascinated lay observer of this topic.

Over the past few years, I have read a couple of articles and books mentioning 'Dark Matter,'  asserting this substance must out-mass (?) conventional matter by something on the order of four or five to one.  Purportedly, this Dark Matter interacts with the rest of the universe only gravitationally.  Could this 'Q Thruster' be somehow interacting Dark Matter?    Or is Dark Matter one and the same with the 'Quantum Vacuum?'

Also, I remember reading mention many years ago that what started the interest in this type of space drive came a as a result of investigating disruptions in the orbits of satellites using microwave devices - the conventional onboard thrusters were having to fire more often to keep the satellites in place.  Any truth to that?  Star Drive?  Rodal? Anybody else?
Title: Re: EM Drive Developments
Post by: Rodal on 09/13/2014 11:39 PM
@ThinkerX

1) <<is Dark Matter one and the same with the 'Quantum Vacuum?'>> No, not at all.  They are not related.  See this link for virtual particles and the quantum vacuum:  http://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/&nbsp; . 

2) We have "known" about Dark Matter for some time (1930's) because its existence is needed to justify the observed gravitational effects responsible for the orbital velocities of stars in our galaxy and the orbital velocities of galaxies in galaxy clusters.

3) <<Could this 'Q Thruster' be somehow interacting Dark Matter?>> that is NOT the explanation put forth by the principal NASA researcher (Dr. White), nor by Prof. Woodward, or anybody else I know of.  Since it has been difficult to detect dark matter (see http://en.wikipedia.org/wiki/Dark_matter#Detection) I personally think that it is unlikely that dark matter would be responsible for the observed experimental effects.

4) As you may gather from this forum, "opinions" abound.  Groups form just as for example it happens when dealing with any controversial subject like global warming, with "climos" and "detractors" taking positions early on and debating each other.  We need to strive to put on our "scientists" hats, as in the peer-review process, with an open but exacting mind, and examine carefully the experimental results and the different models (equations if possible) put forth to justify the experimental results.  :)
Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/14/2014 01:33 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254889#msg1254889">Quote from: Rodal on 09/13/2014 02:47 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254886#msg1254886">Quote from: JohnFornaro on 09/13/2014 02:40 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254748#msg1254748">Quote from: Rodal on 09/13/2014 01:16 AM</a>
Dr . Woodward ... it is a radiation reaction interaction, presumably, that involves the Wheeler-Feynman ...

Mr. Woodward does not answer any questions at all by saying "presumably".

Yes Dr. Woodward clearly said "presumably" (in the video I referenced)

Glad we agree.  No questions are "answered" by "presumably", nor by ignoring the body of Mr. Woodwared's work.  But hey.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/14/2014 01:33 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254890#msg1254890">Quote from: GoatGuy on 09/13/2014 02:48 PM</a>
Now, missions to Saturn in 286 days?

Thought it was 788.   Never was good with numbers.

Quote
Sizzle, schmizzle...

Well, remember they're selling the sizzle, not the steak, and many other people, some actual scientists included, are asking, 'where's the beef?'

[quote-GoatGuy]But Goat, the Mach Woodward is deflecting the intertial energy of the Universe, not unlike how a sailboat's sails are harvesting energy from the passing wind...[/quote]

Fix your quotes.  'Tweren't me what sed dat.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/14/2014 01:33 AM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254949#msg1254949">Quote from: RotoSequence on 09/13/2014 07:23 PM</a>
To get a... well, obvious question out of the way, if the effect is real, and is predicted to scale up, why not build a 33 kilowatt device, place it on an old fashioned weighing scale, and wow the world with a whole pound of thrust?

Shhhhh.

Title: Re: EM Drive Developments
Post by: birchoff on 09/14/2014 05:09 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255040#msg1255040">Quote from: JohnFornaro on 09/14/2014 01:33 AM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254949#msg1254949">Quote from: RotoSequence on 09/13/2014 07:23 PM</a>
To get a... well, obvious question out of the way, if the effect is real, and is predicted to scale up, why not build a 33 kilowatt device, place it on an old fashioned weighing scale, and wow the world with a whole pound of thrust?

Shhhhh.

There is no conspiracy here, They just havent not proven beyond reasonable doubt that the effect is real. A nice way of characterizing these developments is like seeing smoke rising on the horizon. We would like to believe it is fire but we most investigate (experiment) to find out if our gut feeling is accurate.

Title: Re: EM Drive Developments
Post by: birchoff on 09/14/2014 05:27 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254872#msg1254872">Quote from: Rodal on 09/13/2014 02:14 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254858#msg1254858">Quote from: birchoff on 09/13/2014 01:04 PM</a>

@PaulMarch

Not sure if you will be able to answer this or not but, are there any plans for EagleWorks to carry out tests on Woodward's M-E devices?

@birchoff

See this paper by Paul March, Fig.7 and Fig.8, p.1330:
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=31119.0;attach=496011

FIGURE 7. Woodward’s Mach-2MHz MLT Test Article, vxB core & March’s Test Stand.
FIGURE 8. Mach-2MHz MLT Test Results - Predicted Thrust is 1.3 / 5.0 Milligram-Force.

and this paper by Dr. White, slide 40:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf

It appears from this that Paul March's/Dr.Woodward's device is the one tested in the 2005 campaign shown by Dr. White giving:

Thrust ~ 3 mN

Specific Force ~ 0.3 N/kW

@Rodal

Thanks for the pointers. I was looking for that deck that you linked to on NTRS. I believe Dr. White used it in a presentation I saw this year. Anyway, the most interesting thing about that deck is it seems like there is mounting evidence that there really is something here. Though what I really wonder about is if the Boeing SFE test article had such good results, what happened to it? are there any future plans for further testing on that particular design. I cannot seem to find any information via google or NTRS documenting the test campaign that Boeing device is said to be apart of. I hope it is not covered by NDA...

Title: Re: EM Drive Developments
Post by: RotoSequence on 09/14/2014 05:30 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255069#msg1255069">Quote from: birchoff on 09/14/2014 05:09 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255040#msg1255040">Quote from: JohnFornaro on 09/14/2014 01:33 AM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254949#msg1254949">Quote from: RotoSequence on 09/13/2014 07:23 PM</a>
To get a... well, obvious question out of the way, if the effect is real, and is predicted to scale up, why not build a 33 kilowatt device, place it on an old fashioned weighing scale, and wow the world with a whole pound of thrust?

Shhhhh.

There is no conspiracy here, They just havent not proven beyond reasonable doubt that the effect is real. A nice way of characterizing these developments is like seeing smoke rising on the horizon. We would like to believe it is fire but we most investigate (experiment) to find out if our gut feeling is accurate.

Star-Drive's been working on this stuff for years, and has built said devices himself, and he seems to be beyond a shadow of a doubt that these devices are real. High power transmitters aren't especially complex devices, and with how long everyone's been fiddling with them, it seems like it would be an effective use of time and money to build a machine that can demonstrate the effect to the naked eye, even if it wasn't useful for anything else.

Title: Re: EM Drive Developments
Post by: Star One on 09/14/2014 08:40 AM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255071#msg1255071">Quote from: RotoSequence on 09/14/2014 05:30 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255069#msg1255069">Quote from: birchoff on 09/14/2014 05:09 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255040#msg1255040">Quote from: JohnFornaro on 09/14/2014 01:33 AM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254949#msg1254949">Quote from: RotoSequence on 09/13/2014 07:23 PM</a>
To get a... well, obvious question out of the way, if the effect is real, and is predicted to scale up, why not build a 33 kilowatt device, place it on an old fashioned weighing scale, and wow the world with a whole pound of thrust?

Shhhhh.

There is no conspiracy here, They just havent not proven beyond reasonable doubt that the effect is real. A nice way of characterizing these developments is like seeing smoke rising on the horizon. We would like to believe it is fire but we most investigate (experiment) to find out if our gut feeling is accurate.

Star-Drive's been working on this stuff for years, and has built said devices himself, and he seems to be beyond a shadow of a doubt that these devices are real. High power transmitters aren't especially complex devices, and with how long everyone's been fiddling with them, it seems like it would be an effective use of time and money to build a machine that can demonstrate the effect to the naked eye, even if it wasn't useful for anything else.

Why is that every time something like this appears that there is certain strand of belief online that they must have had these for years but kept them secret. It's a depressingly recurrent theme for cutting edge technology whatever the field and I don't know what it is says about scientific literacy in the public at large.

Title: Re: EM Drive Developments
Post by: RotoSequence on 09/14/2014 08:47 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255099#msg1255099">Quote from: Star One on 09/14/2014 08:40 AM</a>
Why is that every time something like this appears that there is certain strand of belief online that they must have had these for years but kept them secret. It's a depressingly recurrent theme for cutting edge technology whatever the field and I don't know what it is says about scientific literacy in the public at large.

I'm not asking why or claiming that he's keeping it secret. I'm asking why a larger one, which would (I hope) help demonstrate that EM drive technology is a real thing, hasn't been built yet.

Title: Re: EM Drive Developments
Post by: Star One on 09/14/2014 12:02 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255102#msg1255102">Quote from: RotoSequence on 09/14/2014 08:47 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255099#msg1255099">Quote from: Star One on 09/14/2014 08:40 AM</a>
Why is that every time something like this appears that there is certain strand of belief online that they must have had these for years but kept them secret. It's a depressingly recurrent theme for cutting edge technology whatever the field and I don't know what it is says about scientific literacy in the public at large.

I'm not asking why or claiming that he's keeping it secret. I'm asking why a larger one, which would (I hope) help demonstrate that EM drive technology is a real thing, hasn't been built yet.

I wasn't really referring to your post just making a more general point.:)

Back on topic if this passes muster on further ground testing, would it at some point be considered for a tech demonstrator cubesat?

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/14/2014 01:23 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255069#msg1255069">Quote from: birchoff on 09/14/2014 05:09 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255040#msg1255040">Quote from: JohnFornaro on 09/14/2014 01:33 AM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254949#msg1254949">Quote from: RotoSequence on 09/13/2014 07:23 PM</a>
...why not build a 33 kilowatt device...

Shhhhh.

There is no conspiracy here...

And no sense of humor either.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/14/2014 01:57 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254949#msg1254949">Quote from: RotoSequence on 09/13/2014 07:23 PM</a>
To get a... well, obvious question out of the way, if the effect is real, and is predicted to scale up, why not build a 33 kilowatt device, place it on an old fashioned weighing scale, and wow the world with a whole pound of thrust?

Seriously, this time:

The cost and difficulty of scaling to that degree is prohibitive.

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/14/2014 02:01 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254890#msg1254890">Quote from: GoatGuy on 09/13/2014 02:48 PM</a>
HSF.  HSF?  Ah... Human Space Flight.  See... I'm a newbie.

No problemo.  The acronym directory on this site misses some of the important ones:  TLA, BFR, IDK...

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/14/2014 02:02 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255071#msg1255071">Quote from: RotoSequence on 09/14/2014 05:30 AM</a>
High power transmitters aren't especially complex devices, and with how long everyone's been fiddling with them, it seems like it would be an effective use of time and money to build a machine that can demonstrate the effect to the naked eye, even if it wasn't useful for anything else.

As I point out often, I've been to Arizona, and have a well developed sense of Yuma.

Anybody with both arms on the armchair would realize that scaling the device up to 33kW would be a huge undertaking.

As a BOE yardstick metric, consider the mass of the testing device with the expected forces to be demonstrated.  While the ratio of device mass to detected force might very well decrease should a larger test device be devised, the cost of actually designing and manufacturing the device would require many more people and subcontractors on the team.  So there's that.

Consider also the small vacuum chamber used in this setup.  Larger ones are available, but again, costs would be larger too.

It's not the "complexity" of high power transmitters that is at point; it is rather the ability to reduce the spurious forces from the experimental setup.  It certainly seems like this would be easier to do at a larger scale, but which larger scale?

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/14/2014 02:05 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255099#msg1255099">Quote from: Star One on 09/14/2014 08:40 AM</a>
...It's a depressingly recurrent theme for cutting edge technology whatever the field and I don't know what it is says about scientific literacy in the public at large.

For starters, take a quick vacation in Arizona.  [Rolls eyes.]

For seconds, you're confusing the "public at large" with, in my case, a guy who has read, over the last five years, every last word on this topic as presented on this forum, who has downloaded and read every paper, and who has also supported the work by purchasing the author's publications, including Sciama, Ciufolini and Wheeler, and others.  I have a readily detectable mass effect on my bookshelf at least.

Finally, for thirds, the "public at large" believes that warp drive is around the corner, thanks to misleading advertising. 

It isn't.

You may not claim exlusive rights to the term "misleading advertising".  The only promise that the propellantless propuslsion teams should be making, is that they can create a device which repeatably demonstrates that the forces do indeed exist and can be harnessed in practical applications.

No need to invoke the c-word.

As to the theory itself, which should also be discussed, there is this (again):

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254717#msg1254717">Quote from: frobnicat on 09/12/2014 10:57 PM</a>
But (again) I'm against a "what if it works" scenario that wont go to all the inescapable consequences, when the consequences are on firm ground that couldn't possibly be overtaken by the hypothesis.

Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 03:19 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255070#msg1255070">Quote from: birchoff on 09/14/2014 05:27 AM</a>

@Rodal

Thanks for the pointers. I was looking for that deck that you linked to on NTRS. I believe Dr. White used it in a presentation I saw this year. Anyway, the most interesting thing about that deck is it seems like there is mounting evidence that there really is something here. Though what I really wonder about is if the Boeing SFE test article had such good results, what happened to it? are there any future plans for further testing on that particular design. I cannot seem to find any information via google or NTRS documenting the test campaign that Boeing device is said to be apart of. I hope it is not covered by NDA...

******************
Here I compare the experimentally measured Thrust Force and the Specific Force (defined as Thrust Force / Input Electric Power) for the different devices tested at NASA Eagleworks.

From this comparison it appears that the latest round of tested devices (the Cannae and the Fustrum Cavity) have among the lowest measured Thrust Force and the lowest Specific Force.

Since what we are looking for is the highest Thrust Force and the highest Specific Force possible, why is the latest discussion in this forum concentrating on the performance of the latest round of tested devices, when they appear to have among the lowest measured thrust forces and the lowest specific force ?

******************

Referring to slide 40 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf:

The largest THRUST force measured is for Shawyer/SPR Ltd.'s microwave device:

16 to 170 mN

However, it also happens to have among the LOWEST Specific Force (in that slide, but still significantly higher  than the specific forces measured in the latest round for the Cannae and Tapered Frustum cavity -see below):

0.02 to 0.4 N/kW

The largest SPECIFIC FORCE measured is for the Boeing/DARPA device:

1 to 20 N/kW but the upper range was produced only by an unexplained anomalous thrust (one out of 8 pulses)
the average thrust was 3N/kW

but (when compared with the Shawyer/SPR's  device numbers above), with very small thrust force:  20 to 110 uN  (again, the 110 uN is for one anomalous thrust force out of 8 pulses,  the average of the other ones is 20 uN)


Also notice that Dr. White writes

<<The magnitude of the [Boeing/DARPA] thrust scaled approximately with the cube of the input voltage>>
and
<<The magnitude of the [Boeing/DARPA] thrust  is dependent on the AC content of the turn-on and turn-off pulse>>

and I notice:

the Boeing/DARPA measurements show a sudden impulse of very short duration instead of the practically square pulses measured with the latest tested devices (Cannae and (Fustrum) Tapered Cavity). 

It is NOT clear to me whether Dr. White is reporting on measurements his Eagleworks lab conducted on the Shawyer/SPR Ltd.'s device, or whether he is reporting measurements made elsewhere with the Shawyer/SPR Ltd.'s device.
 
////////////////

For the latest round of NASA Eagleworks measurements (in the paper "Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum"):

Cannae Testing:

THRUST Force average:   40 uN
Specific Force:  0.0014 N/kW
______________________________

Tapered (Frustum) Cavity Testing: 

THRUST Force average: 50 to 90 uN
Specific Force:  0.003 N/kW to 0.0054 N/kW

Where I obtained the "Specific Force" by dividing the Thrust Force by the Input Electric Power (for example, for the Tapered Cavity 16.9 Watts electric).

////////////////

Everybody: please take a look at this comparison, and provide some feedback as to why the latest discussion in this forum is concentrating on the performance of the latest round of tested devices, when they appear to have among the lowest measured thrust forces and the lowest specific force ?

Have I misinterpreted something in the above comparison?
If so, how is the Specific Force calculated in slide 40 of Dr. White's presentation in the above link and elsewhere in his papers?

Also notice that <<Figure 25. 2MW NEP (90t spacecraft) Crewed Titan/Enceladus Mission with 0.4N/kWe thrust to power>> in the "Anomalous thrust..." paper uses 0.4N/kW (compare this with the Boeing/DARPA figure given in slide 40 above, which is 1 to 20 N/kW).  Of course I do understand that the  Crewed Titan/Enceladus Mission must have assumed an amount of thrust much larger than the minute thrust measured at Eagleworks for the Boeing/DARPA device  :), and that must be also the object of your criticism (the assumption that the devices can be eventually scaled up to produce required thrust and specific forces)

Title: Re: EM Drive Developments
Post by: cuddihy on 09/14/2014 03:35 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255150#msg1255150">Quote from: JohnFornaro on 09/14/2014 02:05 PM</a>

I have a readily detectable mass effect on my bookshelf at least.

Thread winner! Nice quip John.

As for the "why no cubesat test," so far I don't believe any of the testing of Eagleworks has been of steady-state devices, and when you factor in how much the power circuits would add to the mass, at current force levels you would need a lot of sustained thrust time to see an orbital mechanics effect from ground-based observation.

Title: Re: EM Drive Developments
Post by: Stormbringer on 09/14/2014 04:43 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255150#msg1255150">Quote from: JohnFornaro on 09/14/2014 02:05 PM</a>

Finally, for thirds, the "public at large" believes that warp drive is around the corner, thanks to misleading advertising. 

It isn't.


Oh, i am not the public at large either. but i think warp drive or something of that general class of thing really is around the corner. not because the hard data warrants that perception. but because the trend of discovery seems to suggest it.

A decade or two ago you would find as close to absolute silence on the topic as possible. now there are papers on university experiments and experimental labs, commercial industry investigations such as boeing. Govt investigations such as NASA all using several different approaches and apparatuses. I have now seen solutions to Relativity maths that support the things. I have flat out seen Science (<---personification) begin to "admit" that Gravity and several forces are related. E'G; an article where Tajmar's experiment was discussed Revealed that GR predicts a coupling of gravity and magnetism or gravity and EM. At that point Tajmar and his results become secondary (good thing too) what became central to me was that GR actually says: Gravity and magnetism or EM are coupled, related and therefore interchangeable.

That's just one example.  So lately science has been cooperating with my plans to obtain a star cruiser.

I have a media reporting rule of thumb about research and articles on research. if there is one article and then silence then the research will produce no fruit. if you have a later article well something could happen, maybe. but if you have three on the same topic over time then you will probable see fruit from it in the future. it works more often that it fails. that's what rule of thumb means.  but i am optimistic. probably more than warranted. But i think that sooner rather than later someone will find the key and unlike fusion's timeline, one of these EM things or a similarly scientifcally disreputable thing will be reality.

Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 05:22 PM
To put this comparison more bluntly:

Ratio of measurements for Shawyer/SPR Ltd.'s device compared to Cannae's device:

THRUST FORCE: 400 to 4250 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device
SPECIFIC FORCE  ( Thrust Force / Input Electric Power) : 14 to 286 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device

_____________________________________________________________________________

Ratio of measurements for Boeing/DARPA's device compared to Cannae's device:

THRUST FORCE: 0.5 to 2.75 times higher for Boeing/DARPA's device than for Cannae's device
SPECIFIC FORCE  ( Thrust Force / Input Electric Power): 714 to 14300 times higher for Boeing/DARPA's device than for Cannae's device

_____________________________________________________________________________

Since what we are looking for is the highest Thrust Force and the highest Specific Force possible, why is the latest discussion in this forum concentrating on the performance of the latest round of tested devices, when they appear to have among the lowest measured thrust forces and the lowest specific force ?
Title: Re: EM Drive Developments
Post by: aero on 09/14/2014 06:12 PM
A general question, but related if it has the right answer. :)

Say that you set up a Casimir force experiment using two parallel plates close together and detected the Casimir force. What would happen to the force if you somehow transmitted a powerful RF energy beam between the plates?

Hint -
a. nothing
b. the force decreases
c. the force increases.
Title: Re: EM Drive Developments
Post by: JPLeRouzic on 09/14/2014 06:13 PM
Hi,
@Rodal: For a long time there was social pressure against Shawyer results and people were reluctant to show support. Shawyer was not supported by a big organization, but when DARPA in 2011 gave lots of publicity to Dr White at 100YSS conference, people's stance changed. Because this time, such research was supported by big organisations (as Stormbringer just said in his last post).
Title: Re: EM Drive Developments
Post by: Star One on 09/14/2014 06:15 PM


<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255167#msg1255167">Quote from: cuddihy on 09/14/2014 03:35 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255150#msg1255150">Quote from: JohnFornaro on 09/14/2014 02:05 PM</a>

I have a readily detectable mass effect on my bookshelf at least.

Thread winner! Nice quip John.

As for the "why no cubesat test," so far I don't believe any of the testing of Eagleworks has been of steady-state devices, and when you factor in how much the power circuits would add to the mass, at current force levels you would need a lot of sustained thrust time to see an orbital mechanics effect from ground-based observation.

Thanks for answering this. So it's going to need a lot more development to get to this stage then.

Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 06:17 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255206#msg1255206">Quote from: JPLeRouzic on 09/14/2014 06:13 PM</a>
Hi,
@Rodal: For a long time there was social pressure against Shawyer results and people were reluctant to show support. Shawyer was not supported by a big organization, but when DARPA in 2011 gave lots of publicity to Dr White at 100YSS conference, people's stance changed. Because this time, such research was supported by big organisations (as Stormbringer just said in his last post).
Hi,

@JPLeRouzic:  Do you know whether the (Thrust Force and Specific Force) numbers given by Dr. White in his slide 40 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf for Shawyer/SPR Ltd.'s device are for

A) experimental results for Shawyer/SPR Ltd.'s device obtained at his NASA Eagleworks Lab?,
or
B) is Dr. White reporting (Thrust Force and Specific Force) numbers obtained elsewhere ?

_____________________________________

This is the text in slide 40 of Dr. White's presentation:

<<
SPR Ltd. Has produced several Microwave test articles. Claim is they produce thrust with just electric power input.

• Shawyer’s theoretical model has been deemed non-viable by scientific community (rightly so)

Thruster assessed against Q-thruster models and analysis suggests this may be a microwave version of a quantum vacuum plasma thruster.

• Tapered shape creates virtual toroid of active volume that can realize net thrust in virtual plasma.
• Microwave Q-thrusters would not be restricted to tapered construction.

16-170 mN Thruster
Specific Force 0.02-0.4N/kW


Prototype 16mN @ 850W,  0.02N/kW
Dynamic Test Article 96mN @ 334W, 0.3N/kW
High fidelity Test Article 170mN @ 450W, 0.4N/kW

Thrust magnitude increased over multiple test devices from 16 to 170mN

If Q-Thruster theory accounts for measured force, then microwave test articles may have ability to reach >10N/kW


Chinese university claims to have duplicated EM Drive tests , but no way for U.S. to evaluate credibility (so we have ignored it)

16-170 mN Thruster
Specific Force 0.02-0.4N/kW

>>

Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 06:34 PM
This is the text for Boeing/DARPA in slide 40 of Dr. White's presentation (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf ):

<<SFE Test Article at JSC

In 2013, Boeing/DARPA sent Eagleworks Lab an SFE test article for testing and evaluation

Evaluation of the test article in and out of a Faraday Shield performed from Feb through June 2013.

• There is a consistent transient thrust at device turn-on and turn-off that is consistent with Qthruster physics
• The magnitude of the thrust scaled approximately with the cube of the input voltage (20-110uN).
• The magnitude of the thrust is dependent on the AC content of the turn-on and turn-off pulse
• Specific force of transient thrust was in the ~1- 20 N/kW range.

~20-110 uN Thrust Pulses
Specific Force ~1-20N/kW
>>

NASA Eagleworks also provided this information in a 2013 Newsletter, which is available in the Internet from this link:  https://xa.yimg.com/kq/groups/86787010/513081407/name/Eagleworks+Newsletter+2013.pdf

that reads:

<<NASA/Boeing/SFE Campaign: Boeing/DARPA sent Eagleworks Lab an SFE test article for testing and
evaluation. The guest thruster was evaluated in numerous test configurations using varying degrees of
Faraday shielding and vacuum conditions. Observations show that there is a consistent transient thrust
at device turn-on and turn-off that is consistent with Q-thruster physics. The magnitude of the thrust
scaled approximately with the cube of the input voltage (20-110uN). The magnitude of the thrust is
dependent on the AC content of the turn-on and turn-off pulse. Thrust to power of transient thrust was
in the ~1-20 N/kW range

Peak + Current at 20kV: ~331nA
Peak - Current at 20 kV: ~280nA
Average On/Off thrust pulse= 19.9uN
Specific Thrust = 3.25 N/kWe

~110uN Anomalous Turnoff Pulse with same peak input power implies: ~18.0 N/kWe.>>
Title: Re: EM Drive Developments
Post by: ThinkerX on 09/14/2014 07:34 PM
Rodal-

Regarding the tests of the Boeing Device, and how the thrust was much greater than with the  Shawyer device:

You began your posts here with a strong suspicion the Shawyer results, at least were likely the result of thermal artifacts.  Would such a suspicion still be warranted with the much more impressive results for the Boeing device?

Also:  thank you for the links on quantum particles and Dark Matter.  One of the reasons I brought up Dark Matter in the first place was because you were concerned that Doctor White postulated far to great a quantum vacuum density.  I was wondering if the Dark Matter density might be sufficient to resolve this, and maybe better account for the 'arrow of time' issues you were discussing earlier. 

That said:

[humor] possibly these various engineering teams could benefit from having a good English teacher writing, or at least critiquing their papers?  Seems to me a fair part of what we are discussing here might be resolved with clearer writing in the reports. [/humor]

Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 07:47 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255217#msg1255217">Quote from: ThinkerX on 09/14/2014 07:34 PM</a>
Rodal-

Regarding the tests of the Boeing Device, and how the thrust was much greater than with the  Shawyer device:


@ThinkerX

No, you have this backwards.  The reported thrust force for the Shawyer/SPR Ltd.'s device are 800 to 1500 times larger than the reported thrust force numbers for the Boeing/DARPA's device.

It is the reported specific force that is greater for the Boeing/DARPA device than for the Shawyer/SPR Ltd.'s.

But, although Dr. White tested the Boeing/DARPA device, as I stated it is NOT clear whether Dr. White is reporting numbers measured at NASA Eagleworks for the Shawyer device or numbers that were measured elsewhere at other labs.

Title: Re: EM Drive Developments
Post by: aero on 09/14/2014 07:52 PM

an interesting paper by Dr. White.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf)

In particular, I find the Math toward the end of the slide show  interesting.
Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 07:54 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255217#msg1255217">Quote from: ThinkerX on 09/14/2014 07:34 PM</a>
Rodal-

....

You began your posts here with a strong suspicion the Shawyer results, at least were likely the result of thermal artifacts.  Would such a suspicion still be warranted with the much more impressive results for the Boeing device?

....

@ThinkerX,

I began my posts with an e-mail I sent to Dr. White concerning his latest testing campaign with the Cannae and the Fustrum Cavity drive.  I never mentioned the Shawyer results in that e-mail/post. 

I cannot comment at this point on the reported numbers for Shawyer, I don't even know whether Dr.White performed those tests or he is simply reporting numbers tested elsewhere. 

***I fully admit to have been confused, and I am still confused as to whether Dr. White ever tested Shawyer's drive or whether he just reported in Power Point slides results obtained for Shawyer's drive elsewhere.  At one point in time I assumed (perhaps incorrectly) that the Fustrum "Tapered Cavity" device tested by Dr. White in his last campaign was another type of Shawyer's  drive.   If somebody could clarify this it would be much appreciated  :)

Concerning the Boeing/DARPA device all I have is that slide (and the similar information in the newsletter) I reported.  I am trying to have people at this forum clarify the numbers I posted, to verify that my reading is correct.  Furthermore I do not have any report on precisely how the Boeing/DARPA device was tested, and I made a point that the measurements of the Boeing/DARPA device show a very short-duration impulse (which Dr.White says is associated with on/off AC) instead of the rectangular pulses of longer duration observed with other devices.

Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 07:59 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255217#msg1255217">Quote from: ThinkerX on 09/14/2014 07:34 PM</a>
Rodal-

...One of the reasons I brought up Dark Matter in the first place was because you were concerned that Doctor White postulated far to great a quantum vacuum density. ...

**** I write the following as an explanation  :D .  I fully understand that the subject we are addressing is complicated, a lot of the information is in PowerPoint presentations and not in full papers, so a lot is subject to interpretation - please consider that my interpretation may be wrong !****

No, I was NOT "concerned that Doctor White postulated far too great a quantum vacuum density". On the contrary. Instead I stated that Dr. White used in his mathematical calculations a value for a "local quantum vacuum density" that is several orders of magnitude higher than the zero-point quantum vacuum density.

This was to answer @frobnicat and others in this forum that were criticizing Dr. White's theory on the basis that if the quantum vacuum density is already a zero-point density, obviously one cannot extract any energy from it, because it is already at the zero-point.  @frobnicat's argument is entirely correct (if somebody would be using the zero-point energy -which Dr. White did not do), that's why great physicists like Pauli, Feynman, de Witt and Schwinger abhorred the explanation for the Casimir effect based on "negative energy" and "negative mass".  I completely agree with Schwinger's explanation that the Casimir effect does not involve any "negative energy" or "negative mass".  Schwinger's explanation (based on a retarded charge effect, a van der Waal force) is what is taught at MIT -nothing to do with "negative energy".   

Furthermore, Dr. White didn't "postulate" a value several orders of magnitude higher for the "local quantum vacuum" out of thin air.  On the contrary, Dr. White derived (based on a Mean Free Path argument) this higher value for the local quantum vacuum.

Essentially I was asking people on this forum to read Dr. White's equations, and address Dr. White's theory instead of a toy model that is NOT Dr. White's theory.

And do NOT take what I write here as a sponsorship of Dr. White's theory either.  I am just asking for a fair peer-review of Dr. White's theory. 

If you ask for my personal viewpoint I would still seek for an explanation using more conventional physics, as for example when Schwinger successfully explained the Casimir effect.

Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 08:36 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255217#msg1255217">Quote from: ThinkerX on 09/14/2014 07:34 PM</a>
One of the reasons I brought up Dark Matter in the first place was because you were concerned that Doctor White postulated far to great a quantum vacuum density.  I was wondering if the Dark Matter density might be sufficient to resolve this, and maybe better account for the 'arrow of time' issues you were discussing earlier. 

That said:

[humor] possibly these various engineering teams could benefit from having a good English teacher writing, or at least critiquing their papers?  Seems to me a fair part of what we are discussing here might be resolved with clearer writing in the reports. [/humor]

You might be right.  An Astrophysicist I know also brought Dark Matter as a possible explanation.  However, another issue I brought in the discussion with him (besides the fact that we have not been able to directly detect Dark Matter and find out exactly what kind of weakly interacting massive particle it is, is that the amount of Dark Matter in our location in the Galaxy is very small according to some numerical solutions of gravitational models based on measurements.  The  Astrophysicist retaliated showing that this is hotly debated, and there is an excellent team at Harvard that a) thinks that the amount of Dark Matter is larger (than in the paper that said the amount was small) and b)thinks that we may know soon how much Dark Matter is around the Earth.
_________________________

Also observe that an interpretation of Dr. White's theory is that it involves Dark Energy, instead of Dark Matter, because Dark Energy is related to the cosmological constant in General Relativity, which is the vacuum energy.

Dr. White also has some interesting ideas on gravity, as an emergent force and not a fundamental force (yes I know that there is good criticism of the idea of gravity as an emergent force...).

_________________________

Concerning <<might be resolved with clearer writing >> I fully agree, starting with my own writings  :) .  We try to do our best  :)

Fortunately, in a forum like this, it is "a work in progress" and we can, as a crowd, arrive at a better understanding. :)

Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 08:39 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255225#msg1255225">Quote from: aero on 09/14/2014 07:52 PM</a>

an interesting paper by Dr. White.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf)

In particular, I find the Math toward the end of the slide show  interesting.

Thanks @aero for bringing this up. I wish we would address slides 56 to 60 of this paper   :)

**** and I don't mean this as a criticism, the equations of Dr. White are scattered in several Power Point slide presentations, I have NOT been able to find them all contained in a single entire paper
I mean this constructively, the more we address Dr. White's equations, the more fair our assessment and also the better we will understand whether his explanations are plausible or not

Title: Re: EM Drive Developments
Post by: bad_astra on 09/14/2014 09:52 PM
Can we please not try to drum up goatguy on this forum?
Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 10:11 PM

Done
Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/14/2014 11:20 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255167#msg1255167">Quote from: cuddihy on 09/14/2014 03:35 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255150#msg1255150">Quote from: JohnFornaro on 09/14/2014 02:05 PM</a>

I have a readily detectable mass effect on my bookshelf at least.

Thread winner! Nice quip John.

As for the "why no cubesat test," so far I don't believe any of the testing of Eagleworks has been of steady-state devices, and when you factor in how much the power circuits would add to the mass, at current force levels you would need a lot of sustained thrust time to see an orbital mechanics effect from ground-based observation.

Yet, that is exactly what is necessary.  The terrestrial based apparatus seems subject to many more constraints than a free body experiment would be subject to. Don't tell the proponents that I'm suggesting an appropriate scaling up of their apparatus.  They have neither a sense of humor nor perspective.

Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 11:34 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255278#msg1255278">Quote from: JohnFornaro on 09/14/2014 11:20 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255167#msg1255167">Quote from: cuddihy on 09/14/2014 03:35 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255150#msg1255150">Quote from: JohnFornaro on 09/14/2014 02:05 PM</a>

I have a readily detectable mass effect on my bookshelf at least.

Thread winner! Nice quip John.

As for the "why no cubesat test," so far I don't believe any of the testing of Eagleworks has been of steady-state devices, and when you factor in how much the power circuits would add to the mass, at current force levels you would need a lot of sustained thrust time to see an orbital mechanics effect from ground-based observation.

Yet, that is exactly what is necessary.  The terrestrial based apparatus seems subject to many more constraints than a free body experiment would be subject to. Don't tell the proponents that I'm suggesting an appropriate scaling up of their apparatus.  They have neither a sense of humor nor perspective.

Given that (see my previous post)

THRUST FORCE: 400 to 4250 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device
SPECIFIC FORCE  ( Thrust Force / Input Electric Power) : 14 to 286 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device

1) Would you consider the Shawyer/SPR Ltd.'s device a "scaled-up" version of the Cannae device -last tested at NASA Eagleworks as per the "Anomalous thrust ..." paper-?

or

2) Are the numbers quoted by Dr. White for Shawyer/SPR Ltd.'s device  unrepresentative because of A) some mistake I made in my interpretation or B) because Dr. White did NOT test  Shawyer/SPR Ltd.'s device and the numbers he quoted were measured elsewhere?

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/14/2014 11:38 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255164#msg1255164">Quote from: Rodal on 09/14/2014 03:19 PM</a>
Everybody: please take a look at this comparison, and provide some feedback as to why the latest discussion in this forum is concentrating on the performance of the latest round of tested devices, when they appear to have among the lowest measured thrust forces and the lowest specific force ?

Well, I'll tell ya.  The "body" of the work, that I mentioned earlier, is based on an interpretation of Mach, as explained further by Sciama.  With their successive experiments, the experimenters appear to move the mathematical goalposts.  I know that I can't keep up. 

But pragmatically, what happens, is you guys up there talking about all sorts of "effects" and what-have-you, and no reasonably educated infividual can keep up.

Assuming, of course, for purposes of argument, that the term "reasonably educated" only includes that group of people who completely and totally understand, including, without apparent limitations, how to recover the recover the Lamb Shift,  radiation interactions, gravity waves,  Wheeler and Feynman (their theory of the Weak Force), the advanced/retarded wave concept, the cosmological arrow of time, 2nd law of Thermodynamics (which should be sufficient), Weak Force arrow of time, particle radiation, Quantum Mechanics (which is to be expected), the concept of action at a distance, inertia, QM entanglement, prima facie rejection of various premises, time-asymmetry, Wheeler-Feynman absorber theory (oops, we already kinda sorta included that), the "Chung-Freese" metric (to which I admit freely and willingly, total ignorance of, even as a collection of letters)... I give up.

My mathematical defeat doesn't prove success to the method, nor guarantee the expected operation  of the experimental apparatus.

Bottom line, and doubling as executive summary; the effect is not explained for or to the edification of the reasonably educated individual.

We give it our best shot.

Title: Re: EM Drive Developments
Post by: Rodal on 09/14/2014 11:46 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255287#msg1255287">Quote from: JohnFornaro on 09/14/2014 11:38 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255164#msg1255164">Quote from: Rodal on 09/14/2014 03:19 PM</a>
Everybody: please take a look at this comparison, and provide some feedback as to why the latest discussion in this forum is concentrating on the performance of the latest round of tested devices, when they appear to have among the lowest measured thrust forces and the lowest specific force ?

Well, I'll tell ya.  The "body" of the work, that I mentioned earlier, is based on an interpretation of Mach, as explained further by Sciama.  With their successive experiments, the experimenters appear to move the mathematical goalposts.  I know that I can't keep up. 

But pragmatically, what happens, is you guys up there talking about all sorts of "effects" and what-have-you, and no reasonably educated infividual can keep up.

Assuming, of course, for purposes of argument, that the term "reasonably educated" only includes that group of people who completely and totally understand, including, without apparent limitations, how to recover the recover the Lamb Shift,  radiation interactions, gravity waves,  Wheeler and Feynman (their theory of the Weak Force), the advanced/retarded wave concept, the cosmological arrow of time, 2nd law of Thermodynamics (which should be sufficient), Weak Force arrow of time, particle radiation, Quantum Mechanics (which is to be expected), the concept of action at a distance, inertia, QM entanglement, prima facie rejection of various premises, time-asymmetry, Wheeler-Feynman absorber theory (oops, we already kinda sorta included that), the "Chung-Freese" metric (to which I admit freely and willingly, total ignorance of, even as a collection of letters)... I give up.

My mathematical defeat doesn't prove success to the method, nor guarantee the expected operation  of the experimental apparatus.

Bottom line, and doubling as executive summary; the effect is not eplained for or to the edification of the reasonably educated individual.

We give it our best shot.

What you discuss up there are interpretations based on controversial theories (even including higher-dimensional Chung-Freese  :) ).  Instead what I ask has nothing to do with interpretations.  What I ask is concerning the experimental results (NO theory).  According to the numbers I quoted, the Shawyer/SPR Ltd.'s device has a thrust orders of magnitude (400 to 4250 times higher) higher than Cannae's.   Is that correct?

Don't get Chung-Freesed here  :) .  Don't escape in a Chung-Freese brane through a 4-D wormhole  :)

Just look at the thrust numbers   Keep your eyes on the numbers.

Title: Re: EM Drive Developments
Post by: IslandPlaya on 09/14/2014 11:57 PM
As someone said before and in agreement on the experimentalist side of things...
Why doesn't someone get a bloody big 100Kw setup of the devices discussed and measure thrust?
We wouldn't need vacuum chambers or any nonsense.
Why not?
Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 12:00 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255293#msg1255293">Quote from: IslandPlaya on 09/14/2014 11:57 PM</a>
As someone said before and in agreement on the experimentalist side of things...
Why doesn't someone get a bloody big 100Kw setup of the devices discussed and measure thrust?
We wouldn't need vacuum chambers or any nonsense.
Why not?

Do we need to go to 100kW to know the following: Does the Shawyer/SPR Ltd.'s device have a thrust orders of magnitude (400 to 4250 times higher) higher than Cannae device -as quoted by Dr. White- yes or not?  Did Dr. White's lab test the Shawyer/SPR Ltd.'s device, yes or not?

Can someone in this forum answer that, please  :)?

Title: Re: EM Drive Developments
Post by: IslandPlaya on 09/15/2014 12:04 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255295#msg1255295">Quote from: Rodal on 09/15/2014 12:00 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255293#msg1255293">Quote from: IslandPlaya on 09/14/2014 11:57 PM</a>
As someone said before and in agreement on the experimentalist side of things...
Why doesn't someone get a bloody big 100Kw setup of the devices discussed and measure thrust?
We wouldn't need vacuum chambers or any nonsense.
Why not?

Do we need to go to 100kW ? Does the Shawyer/SPR Ltd.'s device have a thrust orders of magnitude (400 to 4250 times higher) higher than Cannae device -as quoted by Dr. White- yes or not?
Ok, start at 1KW then 10KW then 100KW...
The point is its much easier (I think) to construct higher power devices than to detect low thrust levels.
If a 1KW device was to slide down an air-track then the world would change...

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 12:06 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255296#msg1255296">Quote from: IslandPlaya on 09/15/2014 12:04 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255295#msg1255295">Quote from: Rodal on 09/15/2014 12:00 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255293#msg1255293">Quote from: IslandPlaya on 09/14/2014 11:57 PM</a>
As someone said before and in agreement on the experimentalist side of things...
Why doesn't someone get a bloody big 100Kw setup of the devices discussed and measure thrust?
We wouldn't need vacuum chambers or any nonsense.
Why not?

Do we need to go to 100kW ? Does the Shawyer/SPR Ltd.'s device have a thrust orders of magnitude (400 to 4250 times higher) higher than Cannae device -as quoted by Dr. White- yes or not?
Ok, start at 1KW then 10KW then 100KW...
The point is its much easier (I think) to construct higher power devices than to detect low thrust levels.
If a 1KW device was to slide down an air-track then the world would change...

OK I completely agree with you and JohnFornaro on that.  Now,

Does the Shawyer/SPR Ltd.'s device have a thrust orders of magnitude (400 to 4250 times higher) higher than Cannae device -as quoted by Dr. White- yes or not?  Did Dr. White's lab test the Shawyer/SPR Ltd.'s device, yes or not?

Can someone in this forum answer that, please  :)?

Title: Re: EM Drive Developments
Post by: IslandPlaya on 09/15/2014 12:07 AM
I don't know
and
I don't know
Title: Re: EM Drive Developments
Post by: ThinkerX on 09/15/2014 12:09 AM

Quote
an interesting paper by Dr. White.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf

In particular, I find the Math toward the end of the slide show  interesting.

I ran through the slideshow a couple times.  (Am I to interpret the first part as meaning that actual, successful, 'bench-top' warp field experiments have already been conducted?)

The 'mission calculations' for Q-Thruster spacecraft were interesting.  Proxima Centauri in under 30 years?  (Which might also mean a very roughly time to reach Tau Ceti or some such - longer period for acceleration.)

The math in the last section defeated my feeble skills in short order.  The notion of gravity as emergent from vacuum energy, rather than fundamental in and of itself is something I have not come across before.  Wouldn't this have implications for relativity?  Again, the math beat me.

As too...

Quote
THRUST FORCE: 400 to 4250 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device
SPECIFIC FORCE  ( Thrust Force / Input Electric Power) : 14 to 286 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device

1) Would you consider the Shawyer/SPR Ltd.'s device a "scaled-up" version of the Cannae device -last tested at NASA Eagleworks as per the "Anomalous thrust ..." paper-?

or

2) Are the numbers quoted by Dr. White for Shawyer/SPR Ltd.'s device  unrepresentative because of A) some mistake I made in my interpretation or B) because Dr. White did NOT test  Shawyer/SPR Ltd.'s device and the numbers he quoted were measured elsewhere?

Something crucial is missing here.  We have independent (?) groups building mechanisms based on different theories (?), all of which apparently produce positive results (?) of differing magnitudes.   Yet, at best it takes...uncomfortable assumptions... to make these results square with existing theory.   Two thoughts:

First, 'Plato's Cave:' imagine a group of people confined in a large dim room, which so far as they know is the sum total of the universe.  Flickering lights make shadow images on the wall, from which they deduce, or attempt to deduce how their world functions.  Their interpretation of these images becomes quite sophisticated, yet the images remain just that: an image of reality rather than reality itself.    At the Quantum or Dark Energy level, something similar may be in effect here - the theories and models used describe what is *apparently* happening, rather than what is *actually* happening, and worse our innate limitations are such we can't go from one to the other.    The models and theories will always be flawed, and this flaw somehow accounts for (part?) of the differing test results.   (apologies for the horribly botched explanation of Plato's Cave.)

Second thought...been a long, long time since I did any reading on it, as it was considered far fetched fringe material way back in the 70's and 80's...but wasn't there a fellow named Townsend Brown mucking around with something vaguely similar to 'Q-Thrusters' forty or fifty years ago?  Seem to remember the UFO types (apologies again) were all over his work.

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 12:11 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255298#msg1255298">Quote from: IslandPlaya on 09/15/2014 12:07 AM</a>
I don't know
and
I don't know

Thank you

and

Thank you

Title: Re: EM Drive Developments
Post by: IslandPlaya on 09/15/2014 12:16 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255301#msg1255301">Quote from: Rodal on 09/15/2014 12:11 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255298#msg1255298">Quote from: IslandPlaya on 09/15/2014 12:07 AM</a>
I don't know
and
I don't know

Thank you

and

Thank you

Now. Will you answer why higher power devices have not been tested?
My opinion: They have and it works, therefore Top Secret.
What can you say?

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 12:20 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255303#msg1255303">Quote from: IslandPlaya on 09/15/2014 12:16 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255301#msg1255301">Quote from: Rodal on 09/15/2014 12:11 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255298#msg1255298">Quote from: IslandPlaya on 09/15/2014 12:07 AM</a>
I don't know
and
I don't know

Thank you

and

Thank you

Now. Will you answer why higher power devices have not been tested?
My opinion: They have and it works, therefore Top Secret.
What can you say?

I don't know  :)

and

I have no idea

and

If I would know that the answer is top secret, I certainly would not be able to answer it anyway   :)

Title: Re: EM Drive Developments
Post by: IslandPlaya on 09/15/2014 12:24 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255207#msg1255207">Quote from: Star One on 09/14/2014 06:15 PM</a>

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255167#msg1255167">Quote from: cuddihy on 09/14/2014 03:35 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255150#msg1255150">Quote from: JohnFornaro on 09/14/2014 02:05 PM</a>

I have a readily detectable mass effect on my bookshelf at least.

Thread winner! Nice quip John.

As for the "why no cubesat test," so far I don't believe any of the testing of Eagleworks has been of steady-state devices, and when you factor in how much the power circuits would add to the mass, at current force levels you would need a lot of sustained thrust time to see an orbital mechanics effect from ground-based observation.

Thanks for answering this. So it's going to need a lot more development to get to this stage then.
Now. Will you answer why higher power devices have not been tested?
My opinion: They have and it works, therefore Top Secret.
What can you say?

Title: Re: EM Drive Developments
Post by: birchoff on 09/15/2014 12:26 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255195#msg1255195">Quote from: Rodal on 09/14/2014 05:22 PM</a>
To put this comparison more bluntly:

Ratio of measurements for Shawyer/SPR Ltd.'s device compared to Cannae's device:

THRUST FORCE: 400 to 4250 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device
SPECIFIC FORCE  ( Thrust Force / Input Electric Power) : 14 to 286 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device

_____________________________________________________________________________

Ratio of measurements for Boeing/DARPA's device compared to Cannae's device:

THRUST FORCE: 0.5 to 2.75 times higher for Boeing/DARPA's device than for Cannae's device
SPECIFIC FORCE  ( Thrust Force / Input Electric Power): 714 to 14300 times higher for Boeing/DARPA's device than for Cannae's device

_____________________________________________________________________________

Since what we are looking for is the highest Thrust Force and the highest Specific Force possible, why is the latest discussion in this forum concentrating on the performance of the latest round of tested devices, when they appear to have among the lowest measured thrust forces and the lowest specific force ?

I think the answer to this question is simply because EagleWorks only presented a paper that outlined tests on the Cannae and Tapered Frustum. I am equally puzzled as you, since the Boeing device seems to be much more interesting. But outside of the deck and the 2013 update you linked to there is ZERO information about the Boeing test article which I find very curious given the results. From the 2013 update you linked to before, it looks like the Boeing device was tested along side the Cannae and Tapered Frustum. So unless there is some sort of NDA in place or some sort of time constraint on compiling the information necessary for inclusion in the paper or some combination there of. I cannot see a reason for why it wouldn't be included.

On a separate note, from the limited information available I am beginning to wonder if the Boeing device wasn't a Mach Effect/Woodward Effect device.

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 12:35 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255309#msg1255309">Quote from: birchoff on 09/15/2014 12:26 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255195#msg1255195">Quote from: Rodal on 09/14/2014 05:22 PM</a>
To put this comparison more bluntly:

Ratio of measurements for Shawyer/SPR Ltd.'s device compared to Cannae's device:

THRUST FORCE: 400 to 4250 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device
SPECIFIC FORCE  ( Thrust Force / Input Electric Power) : 14 to 286 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device

_____________________________________________________________________________

Ratio of measurements for Boeing/DARPA's device compared to Cannae's device:

THRUST FORCE: 0.5 to 2.75 times higher for Boeing/DARPA's device than for Cannae's device
SPECIFIC FORCE  ( Thrust Force / Input Electric Power): 714 to 14300 times higher for Boeing/DARPA's device than for Cannae's device

_____________________________________________________________________________

Since what we are looking for is the highest Thrust Force and the highest Specific Force possible, why is the latest discussion in this forum concentrating on the performance of the latest round of tested devices, when they appear to have among the lowest measured thrust forces and the lowest specific force ?

I think the answer to this question is simply because EagleWorks only presented a paper that outlined tests on the Cannae and Tapered Frustum. I am equally puzzled as you, since the Boeing device seems to be much more interesting. But outside of the deck and the 2013 update you linked to there is ZERO information about the Boeing test article which I find very curious given the results. From the 2013 update you linked to before, it looks like the Boeing device was tested along side the Cannae and Tapered Frustum. So unless there is some sort of NDA in place or some sort of time constraint on compiling the information necessary for inclusion in the paper or some combination there of. I cannot see a reason for why it wouldn't be included.

On a separate note, from the limited information available I am beginning to wonder if the Boeing device wasn't a Mach Effect/Woodward Effect device.

Please also consider that:

A) The Boeing/DARPA measurements show a sudden impulse of very short duration instead of the practically rectangular pulses measured with the latest tested devices (Cannae and (Fustrum) Tapered Cavity).   That may be a problem concerning the Boeing/DARPA device as what is needed is steady state thrust.

and

B) NO Information gets out on top secret work.  None.  Nada.  At the time of the Manhattan Project you didn't have snapshots with small amounts of information.  You had nothing getting out.  The NASA Eagleworks 2013 update on the Boeing/DARPA device (look at the link) seems to be on a Yahoo server with the address xa.yimg.com. All of these are servers that host the graphic images of Yahoo pages (y=Yahoo + img=image).

Title: Re: EM Drive Developments
Post by: birchoff on 09/15/2014 12:37 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255278#msg1255278">Quote from: JohnFornaro on 09/14/2014 11:20 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255167#msg1255167">Quote from: cuddihy on 09/14/2014 03:35 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255150#msg1255150">Quote from: JohnFornaro on 09/14/2014 02:05 PM</a>

I have a readily detectable mass effect on my bookshelf at least.

Thread winner! Nice quip John.

As for the "why no cubesat test," so far I don't believe any of the testing of Eagleworks has been of steady-state devices, and when you factor in how much the power circuits would add to the mass, at current force levels you would need a lot of sustained thrust time to see an orbital mechanics effect from ground-based observation.

Yet, that is exactly what is necessary.  The terrestrial based apparatus seems subject to many more constraints than a free body experiment would be subject to. Don't tell the proponents that I'm suggesting an appropriate scaling up of their apparatus.  They have neither a sense of humor nor perspective.

As a proponent for continued experimentation into these types of devices, I can say that I would love to see them scaled up and tested in a cubesat. However, I am also aware that nothing is that easy. These devices have not been proven to be real effects yet. which means we have no clue what the operating parameters are. Now as long as there are experiments we can do on terra firma that are cheaper. My vote is to complete those experiments first. Once that is done we can begin planning the cubesat version.

Title: Re: EM Drive Developments
Post by: aceshigh on 09/15/2014 12:51 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255102#msg1255102">Quote from: RotoSequence on 09/14/2014 08:47 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255099#msg1255099">Quote from: Star One on 09/14/2014 08:40 AM</a>
Why is that every time something like this appears that there is certain strand of belief online that they must have had these for years but kept them secret. It's a depressingly recurrent theme for cutting edge technology whatever the field and I don't know what it is says about scientific literacy in the public at large.

I'm not asking why or claiming that he's keeping it secret. I'm asking why a larger one, which would (I hope) help demonstrate that EM drive technology is a real thing, hasn't been built yet.


not sure, but considering Star Drive is a electric-engineer, I am certain he has a good explanation for why not.

for Mach Effect devices, I know they need piezo-electric materials and ceramics that are just too expensive for anyone without some good financial backup.

Title: Re: EM Drive Developments
Post by: birchoff on 09/15/2014 12:54 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255312#msg1255312">Quote from: Rodal on 09/15/2014 12:35 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255309#msg1255309">Quote from: birchoff on 09/15/2014 12:26 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255195#msg1255195">Quote from: Rodal on 09/14/2014 05:22 PM</a>
To put this comparison more bluntly:

Ratio of measurements for Shawyer/SPR Ltd.'s device compared to Cannae's device:

THRUST FORCE: 400 to 4250 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device
SPECIFIC FORCE  ( Thrust Force / Input Electric Power) : 14 to 286 times higher for Shawyer/SPR Ltd.'s device than for Cannae's device

_____________________________________________________________________________

Ratio of measurements for Boeing/DARPA's device compared to Cannae's device:

THRUST FORCE: 0.5 to 2.75 times higher for Boeing/DARPA's device than for Cannae's device
SPECIFIC FORCE  ( Thrust Force / Input Electric Power): 714 to 14300 times higher for Boeing/DARPA's device than for Cannae's device

_____________________________________________________________________________

Since what we are looking for is the highest Thrust Force and the highest Specific Force possible, why is the latest discussion in this forum concentrating on the performance of the latest round of tested devices, when they appear to have among the lowest measured thrust forces and the lowest specific force ?

I think the answer to this question is simply because EagleWorks only presented a paper that outlined tests on the Cannae and Tapered Frustum. I am equally puzzled as you, since the Boeing device seems to be much more interesting. But outside of the deck and the 2013 update you linked to there is ZERO information about the Boeing test article which I find very curious given the results. From the 2013 update you linked to before, it looks like the Boeing device was tested along side the Cannae and Tapered Frustum. So unless there is some sort of NDA in place or some sort of time constraint on compiling the information necessary for inclusion in the paper or some combination there of. I cannot see a reason for why it wouldn't be included.

On a separate note, from the limited information available I am beginning to wonder if the Boeing device wasn't a Mach Effect/Woodward Effect device.

Please also consider that:

A) The Boeing/DARPA measurements show a sudden impulse of very short duration instead of the practically rectangular pulses measured with the latest tested devices (Cannae and (Fustrum) Tapered Cavity).   That may be a problem concerning the Boeing/DARPA device as what is needed is steady state thrust.

and

B) NO Information gets out on top secret work.  None.  Nada.  At the time of the Manhattan Project you didn't have snapshots with small amounts of information.  You had nothing getting out.  The NASA Eagleworks 2013 update on the Boeing/DARPA device (look at the link) seems to be on a Yahoo server with the address xa.yimg.com. All of these are servers that host the graphic images of Yahoo pages (y=Yahoo + img=image).

Agreed on the top secret comment. But a NDA is a little bit more forgiving than declaring something Top Secret. For example EagleWorks could have been allowed to only report on the results. Which is what they did. Compared to the Cannae and Tapered device where they were able to report on their construction and the testing protocol.

Title: Re: EM Drive Developments
Post by: frobnicat on 09/15/2014 12:59 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255237#msg1255237">Quote from: Rodal on 09/14/2014 08:39 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255225#msg1255225">Quote from: aero on 09/14/2014 07:52 PM</a>

an interesting paper by Dr. White.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf)

In particular, I find the Math toward the end of the slide show  interesting.

Thanks @aero for bringing this up. I wish we would address slides 56 to 60 of this paper   :)

**** and I don't mean this as a criticism, the equations of Dr. White are scattered in several Power Point slide presentations, I have NOT been able to find them all contained in a single entire paper
I mean this constructively, the more we address Dr. White's equations, the more fair our assessment and also the better we will understand whether his explanations are plausible or not

desperate attempt, please don't read and ignore unless you are yourself desperate :

I understand the interest of addressing those equations but at this level I just can do dimensional analysis (first glance seems ok, but then one wouldn't expect otherwise). Quantitatively from the equations couldn't tell deep insights from mere numerology. A few slides but no paper to the scientifically literate (but not specialist or follower) don't help. Hope someone can clarify because what I'm understanding qualitatively (not much either) is that mass alters "local vacuum density" and that makes either for more "vacuum plasma" to push on, or is it a difference in potentials to exploit ? See how clueless, can't even tell if equation 1 slide 56 is the starting hypothesis and then deriving form there, or if the rest is supposed to illuminate this hypothesis, or if we have some circular reasoning (well, there is some circularity in any successful theory, this can be just "self consistency", not a counter argument by itself), or if this is just a way of expressing in a different way of what we already know in mainstream physics like, you know, for instance naked particle vs dressed particle (and what is expressed as "affected vacuum fluctuation density" would be the "density of the dress") (not likely as this is specific to fields others than gravity while formula 1 is only about energy densities, isn't it ?)

So, naïvely I would say : if something more is linked to local mass_energy density (is that it rho m_local ?) how can you exploit it energetically as it is still a local minimum energy state in its own specificity. Not clear, a classical analogy would be : a liquid (surface of minimum energy) forms a meniscus close to the wall of a container, at this point the surface is higher (take a concave meniscus) than the rest of the surface. That don't make it possible to exploit this difference of height to generate energy as the surface is of minimal energy, given the wall of the container is there : it both makes possible the change of altitude of surface, and prevents that to be used for useful work. If one could instantly make the wall vanish, then this meniscus is no longer a minimum energy surface and work can be recovered, but not more than what it took to "make it vanish". Meaningless talk probably.

Equation 2 : ok so this is principle of equivalence, I guess we could expect the same magnitude as Hawking radiation (no ?), so a bit surprised that a mundane mass density like a dielectric (not even a neutron star) could make much difference with nothing. Let's proceed.

Next (still on slide 56)
Quote
The tools of MagnetoHydroDynamics (MHD) can be used to model this modified vacuum fluctuation density analogous to how conventional forms of electric propulsion model propellant behavior.
don't understand (trying) is that : MHD tools used to model the coupling of RF field with this denser vacuum ... ?

There I'm stuck for now.

If the other equations/slides bring something else as to why some better than 1/c thrust/power ratio can be obtained at all (however small, regardless of the fact that vacuum would be denser than usual in a capacitor) it didn't struck me.

Also, on a side note, the proposed mission profiles are calculated with good old Newtonian mechanics, from a given thrust/power ratio. So while it is interesting to discuss the equations deriving such ratio (or the simple possibility of such ratio > 1/c) from possible hypothesis, that shouldn't prevent anyone to draw conclusions of the ratio without resorting to such hypothesis/equations or making calculation in such formalism.


            exotic physics                    Newtonian
Hypothesis ---------------> thrust/power -----------------> result (real cheap energy)


Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 12:59 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255316#msg1255316">Quote from: aceshigh on 09/15/2014 12:51 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255102#msg1255102">Quote from: RotoSequence on 09/14/2014 08:47 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255099#msg1255099">Quote from: Star One on 09/14/2014 08:40 AM</a>
Why is that every time something like this appears that there is certain strand of belief online that they must have had these for years but kept them secret. It's a depressingly recurrent theme for cutting edge technology whatever the field and I don't know what it is says about scientific literacy in the public at large.

I'm not asking why or claiming that he's keeping it secret. I'm asking why a larger one, which would (I hope) help demonstrate that EM drive technology is a real thing, hasn't been built yet.


not sure, but considering Star Drive is a electric-engineer, I am certain he has a good explanation for why not.

for Mach Effect devices, I know they need piezo-electric materials and ceramics that are just too expensive for anyone without some good financial backup.

The Cannae thruster (which has among the lowest thrust force and the lowest specific force measured at NASA Eagleworks) has an (inexpensive) Teflon dielectric resonator.   The Paul March Woodward-Effect devices measurements at NASA Eagleworks showed significantly higher thrust and specific force than the Cannae device...

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 01:37 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255322#msg1255322">Quote from: frobnicat on 09/15/2014 12:59 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255237#msg1255237">Quote from: Rodal on 09/14/2014 08:39 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255225#msg1255225">Quote from: aero on 09/14/2014 07:52 PM</a>

an interesting paper by Dr. White.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf)

In particular, I find the Math toward the end of the slide show  interesting.

Thanks @aero for bringing this up. I wish we would address slides 56 to 60 of this paper   :)

**** and I don't mean this as a criticism, the equations of Dr. White are scattered in several Power Point slide presentations, I have NOT been able to find them all contained in a single entire paper
I mean this constructively, the more we address Dr. White's equations, the more fair our assessment and also the better we will understand whether his explanations are plausible or not

...attempt,.....

Thanks for taking a stab at  it.  Now you have a better idea of what his model is. I'm trying to find the link for a presentation where Dr. White derived his calculation of what he calls the "local vacuum density" as the geometric mean of the local material density (which he calculates from the radius of the hydrogen atom nucleus and the mass of a proton to obtain the density of the hydrogen nucleus) and the quantum vacuum density.  I can no longer find that link using Google   :(.  I recall that Dr. White's calculation was based on a Mean Free Path argument...  In any case, you can see that Dr. White didn't just come up with a "local vacuum density" number to arbitrarily fit experimental results, but that he has at least a "back of the envelope" argument for it...  This "local vacuum density" is of course several orders of magnitude larger than the zero point energy.

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 02:56 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255322#msg1255322">Quote from: frobnicat on 09/15/2014 12:59 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255237#msg1255237">Quote from: Rodal on 09/14/2014 08:39 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255225#msg1255225">Quote from: aero on 09/14/2014 07:52 PM</a>

an interesting paper by Dr. White.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf)

In particular, I find the Math toward the end of the slide show  interesting.

Thanks @aero for bringing this up. I wish we would address slides 56 to 60 of this paper   :)

...

... at this level I just can do dimensional analysis ....

Most problems in Engineering were solved with non-dimensional analysis (think of heat transfer,  Aeronautical Engineering, etc.) and a slide-rule at a time that numerical computations were not available.  Nothing wrong with that  ;) .  And it is always good to have a very simplified physical model that abstracts the main features.

What is out of the ordinary here is that exotic physics (electron/positron pairs of virtual particles modeled as a  MagnetoHydrodynamics plasma) is involved here, but let's see where this leads...

Title: Re: EM Drive Developments
Post by: Stormbringer on 09/15/2014 03:03 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255312#msg1255312">Quote from: Rodal on 09/15/2014 12:35 AM</a>


B) NO Information gets out on top secret work.  None.  Nada.  At the time of the Manhattan Project you didn't have snapshots with small amounts of information.  You had nothing getting out.  The NASA Eagleworks 2013 update on the Boeing/DARPA device (look at the link) seems to be on a Yahoo server with the address xa.yimg.com. All of these are servers that host the graphic images of Yahoo pages (y=Yahoo + img=image).

hmmmm. In Dr whites earlier video i recall Dr white stating that his Q thruster experiments were farther along than his warp interferometry experiment but he could not discuss the former in detail because... he either said it was classified or else subject to secrecy due to NDA or something like that.

as to the Manhattan project several of the scientists on the team were giving data to the soviets for ideological reasons even before the project was finished. They feared America would become an unstoppable evil empire if they were the lone nuclear power.

Title: Re: EM Drive Developments
Post by: birchoff on 09/15/2014 04:07 AM

@Rodal

I think the answer to your thrust descripancy between the Cannae and the Tapered Frustum  devices may be partly answered by the size of the dielectric. According to the pictures and comsol models in the paper the size of the dielectric in the Cannae device has to be much smaller than the die electric in the Tapered Frustum. My guess as to why Cannae has a smaller dielectric would be that the theory they presented at the conference considers the slots in the cavity to be the source of the thrust (you can either buy the paper from AIAA to get access to their theory, or leverage the way back machine here => http://web.archive.org/web/20140517034519/http://cannae.com/ (http://web.archive.org/web/20140517034519/http://cannae.com/), along with the patent descriptions here => https://www.google.com/?tbm=pts&gws_rd=ssl#tbm=pts&q=inassignee:%22Cannae+Llc%22 (https://www.google.com/?tbm=pts&gws_rd=ssl#tbm=pts&q=inassignee:%22Cannae+Llc%22)). Interestingly, since the NASA testing it looks like the inventor at Cannae has moved away from that theory of operation and is building new devices that in the companies words...

Quote
Inventor Guido Fetta has developed a 2nd technology that develops thrust without the use of on-board reaction mass.  This new technology uses RF interactions with a dielectrically loaded waveguide to produce thrust.  This new technology functions by a mechanism that is different from the Cannae Drive thrust mechanism.  Cannae LLC has patent pending status on a wide range of designs based on this new technology.
<<http://www.cannae.com/updates (http://www.cannae.com/updates)

As for your question about the thrust and specific force numbers reported in the Deck for Shawyer's EmDrive. It is my understanding from second and third hand information that while Dr. White originally attempted to replicate Shawyer's device, they failed to get positive results. I believe this is what was being referenced in the paper

Quote
We performed some very early evaluations without the dielectric resonator (TE012 mode at 2168 MHz, with power levels up to ~30 watts) and measured no significant net thrust.
<< Pg 18, Anomalous Thrust Production From RF Test Device.

So if the information is accurate then its most likely that the numbers on slide 40 of that deck are coming from one of Shawyer's papers or the Chinese papers (I have yet to double check that).

Title: Re: EM Drive Developments
Post by: frobnicat on 09/15/2014 10:18 AM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254914#msg1254914">Quote from: Star-Drive on 09/13/2014 05:05 PM</a>
In that vein, I think it would be best to discuss the experiments without addressing any controversial physical explanation for the time being."

Maybe we could split another thread for "Theoretical aspects of space drives" ?

Sill thinking that, between theoretical speculations of stratophysics of the unknown, and down to earth practical experimental apparatus and results inquiries, it is important to address uncontroversial physics consequences of said results, regardless of specific theories. Even if the various propellentless thrusts results weren't guided by any kind of backing theory and had been stumbled on by chance, that wouldn't prevent us to use the effect to the fullest extent permitted by Newtonian laws.

Sorry I will shuffle a little bit the quotation order and select fragments for my dissertation
Quote
PS:  A Hall thruster's input power to thrust efficiency or specific thrust is around 0.05 N/kWe using today's commercially available thrusters.  Air breathing jet engines can have thrust efficiencies of up to ~75 N/kWe at take off, so assuming a 0.40N/kWe for our Copernicus Orbital calculations is not way out on a limb, and in fact is representative of the performance of my first two Mach-Lorentz Thrusters (MLT) that I built in 2003 and 2004 and reported on in my STAIF-2006 paper.

So those mission profiles are sold with the following hypothesis that :

- a thrust/power>>1/c effect is possible,it is independent of speed, without expelling mass (that is without spending more onboard mass than the equivalent mass_energy to power the system, negligible so far)

- approaching 1N/kW is possible/expected/has been measured already

- in this hypothesis "thrust" and "power" retain the meaning they usually have, the observed acceleration of a free floating spacecraft will be thrust/mass, the total energy used by the onboard generator will be the power integrated on time. Mission profiles are calculated with Newtonian dynamics. While backing theories can explain why previous hypothesis hold, one don't need to use those special formalisms to set up mission profiles, just plug in the thrust/power number into classical framework (that is Newtonian when speed<<c and total energy/c² << spacecraft's mass)

Am I wrong on any of that ? Are there any (acquired) speed corrections to the thrust/ratio used in the proposed mission profiles ?

Quote
BTW, I'm a little late is saying this, but tell Goat Guy that he needs to perform his energy conservation analysis in the 4D GRT formalism and not the flat space-time Newtonian version he's been using to date when performing M-E or Q-Thruster based momentum and energy conservation calculations.  Woodward's 2004 M-E derivation paper's appendix A can show what's needed here.

I'm not Goat Guy but what he said about the tremendous practical energy in/practical energy out leverage of the mission profiles seems sensible to me : the net useful result is "very cheap classical energy". If a theory can explain where this energy comes from and keep energy balance overall, great, but that is irrelevant as far as mission profiles are concerned. In what would the 4D GRT be necessary to derive the practical consequences of the effect, would it make any difference for mission profiles ?

Cheap classical useful energy is not shocking by itself, arguably a solar sail has an infinite thrust/power ratio from the standpoint of a spacecraft : net thrust with 0 power. And therefore we could devise some solar windmill that are "free" energy generators. Probably not practical.

Thing is : with the claimed(used in mission profiles) thrust/power ratios approaching 1N/kW we can devise very near practical energy generators, suffice to rotate the thruster at the rim of a rotor with a tangential speed a bit more than 1/ratio = 1km/s. Since there is no complex or moving parts in those thrusters it should be relatively straightforward, the RF generator could be mounted fixed, and give the power through a waveguide coaxial with the shaft. This is only a technological problem of high specific strength materials and maybe some (not enormous) tapering of supporting rotating arm section if a bit more 2km/s needed. If 0.5 chained efficiency of the electric dynamo on the shaft and the RF generator then 5km/s needed with 0.4N/kW to reach breakeven, hard but not impossible.

So the question is, and remains, why the results are not also sold on that possibility, should they hold and be classically interpreted for propulsion purpose, why would it be impossible/taboo to classically derive this incredibly useful consequence of "very cheap energy" generators?

The power/mass ratios might be near 10 W/kg (optimistically say with 1N/kW thruster, 100kg system, generating 1N at 3km/s, 3kW mechanical, 2.7 electric at dynamo, 2kW  used for 50% efficiency 1kW output RF generator, 700W net power breakeven, 7W/kg)
7W/kg is not much specific power but hey, it's free ! A spacecraft 200kg with a 100kg generator like that, and a thruster at 1N/kW would have acceleration of .7/200 = 3.5e-3 m/s², forever, for free.
That is about 100km/s a year, a bit short for interstellar but making roaming the suburbs a breeze.

Has this real possible and desirable consequence of the effect, good energy generators for space (and earth), been mentioned by the proponents of the effect, and if not why not ?

Quote
As for White's Q-Thrusters, energy & momentum conservation is observed by the fact that the vacuum derived propellant has an energy equivalent mass that does have a velocity less than c.  And just like the standard rocket equation, your rocket's maximum obtainable velocity is dependent on the maximum exhaust velocity of the Q-Thruster that is driven by all its local and perhaps gravitational field input energies.  Our current model for same indicates that these vacuum e/p pair like propellant velocities should be in the range of 10,000-to-10,000,000 m/s for the geometries and input power levels we've looked at to date, but of course only if our Q-Thruster model Excel sheet is correct. 

If I understand well, the energy you have to put in the thruster to get the thrust has a mass equivalent, and like for a photon rocket after some point of very very intense onboard power generation the mass of the spacecraft is depleting and therefore we have a rocket equation hence a "maximum" practical attainable speed. Is that it ?

Anyway, either the mission profiles at 0.4 N/kW and absolute (?) speeds < 100km/s are possible, and so is a near practical "cheap energy generator", or the generator is not possible because 0.4N/kW starts to decrease above ~2.5 km/s but then interesting mission profiles are no longer possible either.

Best

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 12:07 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255375#msg1255375">Quote from: birchoff on 09/15/2014 04:07 AM</a>
@Rodal
I think the answer to your thrust descripancy between the Cannae and the Tapered Frustum  devices may be partly answered by the size of the dielectric. According to the pictures and comsol models in the paper the size of the dielectric in the Cannae device has to be much smaller than the die electric in the Tapered Frustum.

Well, the numbers I posted (I am now putting everything in uN, as people may not have noticed the difference between mN and uN, and I am adding the Woodward-Effect devices) (see slide 40 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf ):

Shawyer/SPR Ltd.'s microwave device:

THRUST =  16000 to 170000 uN
SPECIFIC FORCE = 0.02 to 0.4 N/kW

______________________________

Boeing/DARPA device:

THRUST =   20 to 110 uN 
SPECIFIC FORCE = 1 to 20 N/kW

______________________________

Cannae Testing:

THRUST =   40 uN
SPECIFIC FORCE:  0.0014 N/kW
______________________________

Tapered (Frustum) Cavity Testing: 

THRUST = 50 to 90 uN
SPECIFIC FORCE=  0.003 N/kW to 0.0054 N/kW

______________________________

(?)Woodward-Effect device tested in 2004: 

THRUST = 4000 uN
SPECIFIC FORCE=  0.4 N/kW

______________________________

Paul March Woodward-Effect device tested in 2005: 

THRUST = 3000 uN
SPECIFIC FORCE=  0.3 N/kW

______________________________
Show little difference between the performance of the Cannae and the Frustum (Tapered Cavity) devices when compared to the other devices: both of them have Specific Force numbers much lower than the Shawyer/SPR Ltd and Boeing/DARPA devices

and the performance of the Cannae and the Frustum (Tapered Cavity) devices  is also much inferior to the previous tests at NASA Eagleworks performed on the Paul March Woodward-Effect device.

If we have to ignore the very high thrust forces of the Shawyer/SPR Ltd because those numbers are untrustworthy (not from NASA), and if we have to ignore the very high specific force of the Boeing/DARPA device because its thrust force was not a rectangular pulse, but instead an impulse and hence not suitable for steady-state operation, the clear winner both in thrust force and specific force are the  Woodward-Effect devices, they have orders of magnitude greater thrust force and specific force than the lousy-performing Cannae and Frustum (Tapered Cavity) devices recently tested.

So, forget about Microwave Resonators and go back to Woodward-Effect devices ?

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 12:19 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255375#msg1255375">Quote from: birchoff on 09/15/2014 04:07 AM</a>
@Rodal

.....

As for your question about the thrust and specific force numbers reported in the Deck for Shawyer's EmDrive. It is my understanding from second and third hand information that while Dr. White originally attempted to replicate Shawyer's device, they failed to get positive results. ...

So if the information is accurate then its most likely that the numbers on slide 40 of that deck are coming from one of Shawyer's papers or the Chinese papers (I have yet to double check that).

Thank you for checking this. 

I agree with your reasoning.  I am still not 100% sure though, because:

A) Dr. White writes in that slide that he will ignore the Chinese data, so why would he show the Chinese data when he writes that he is simultaneously going to ignore it?
and
B) If the Shawyer data is from experiments done at Shawyer or elsewhere (not at NASA), why show such NASA-unverified Shawyer -data mixed together in a deck of slides with actual NASA data for other devices?

Kind of confusing to me...

Title: Re: EM Drive Developments
Post by: Jossarian on 09/15/2014 01:13 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254383#msg1254383">Quote from: Star-Drive on 09/11/2014 11:22 PM</a>
If we could use nuclear rockets, other choices would be availabe for our propulsion needs, but sadly the nuclear propulsion venue is not available to the US space program due to political issues we all know of, unless of course a fusion power breakthrough shows up on our doorsteps...

Here you go...
http://www.forbes.com/sites/jeffmcmahon/2014/01/04/doe-mentions-technology-behind-the-home-nuclear-reactor-in-funding-opportunity/
http://climate.nasa.gov/news/864/

Isn't NASA’s Langley Research Center working on LENR reactors already?

It is also possible to use something like this:
http://arxiv.org/abs/1305.3913v3

Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/15/2014 01:15 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255293#msg1255293">Quote from: IslandPlaya on 09/14/2014 11:57 PM</a>
As someone said before and in agreement on the experimentalist side of things...
Why doesn't someone get a bloody big 100Kw setup of the devices discussed and measure thrust?
We wouldn't need vacuum chambers or any nonsense.
Why not?

Why not?  Because...

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255147#msg1255147">Quote from: JohnFornaro on 09/14/2014 01:57 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1254949#msg1254949">Quote from: RotoSequence on 09/13/2014 07:23 PM</a>
...why not build a 33 kilowatt device, place it on an old fashioned weighing scale, and wow the world with a whole pound of thrust?

Seriously, this time:

The cost and difficulty of scaling to that degree is prohibitive.

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 02:19 PM
This is the text for Paul March Woodward-Effect device tested in 2005:  (see slide 40 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf )


The test unit was run at 2.13 MHz, yielding an AC electric field of ~20kV/m, and an AC magnetic field of ~27 Gauss.

• Based on the input parameters, the QVPT thrust prediction was 0.63 mN [630 uN]
• The observed thrust was +/- 0.89 mN [890 uN]

The test unit was run at 3.8 MHz yielding an AC electric field of ~20kV/m, and an AC magnetic field of ~48 Gauss.

• Based on the input parameters, the QVPT thrust prediction was 2.79 mN  [2790 uN]
• The observed thrust was +4.91 to -1.96 mN  [+4910 uN to -1960 uN] as measured via a 4900 mN (500gf) load cell

As can be seen to the right, the thrust signal is very clear when the unit is excited.

~3 mN Thrust  [3000 uN]
Specific Force ~0.3N/kW

________________________________

Notice:

1) The Thrust force was NOT measured with NASA's inverted pendulum, but instead with a 4900 mN (500gf) load cell.   If you see Dr. Woodward's paper, you will see that Dr. Woodward abandoned initial (hanging) pendulum testing in favor of load cell testing, because he noticed that pendulum testing introduces inertial artifacts from the pendulum itself.  My opinion : this makes sense to me. 

2) There is excellent agreement (from an engineering viewpoint) between Dr. Woodward's prediction for thrust and the experimental measurements.

3) << the thrust signal is very clear when the unit is excited>>

4) Based on the tested numbers, I don't understand the emphasis on the (Cannae and Frustum Tapered-Cavity) Microwave devices as their performance is very lousy in comparison.
Title: Re: EM Drive Developments
Post by: JohnFornaro on 09/15/2014 02:27 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255297#msg1255297">Quote from: Rodal on 09/15/2014 12:06 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255296#msg1255296">Quote from: IslandPlaya on 09/15/2014 12:04 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255295#msg1255295">Quote from: Rodal on 09/15/2014 12:00 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255293#msg1255293">Quote from: IslandPlaya on 09/14/2014 11:57 PM</a>
As someone said before and in agreement on the experimentalist side of things...
Why doesn't someone get a bloody big 100Kw setup of the devices discussed and measure thrust?
We wouldn't need vacuum chambers or any nonsense.
Why not?

Do we need to go to 100kW ? Does the Shawyer/SPR Ltd.'s device have a thrust orders of magnitude (400 to 4250 times higher) higher than Cannae device -as quoted by Dr. White- yes or no?

Ok, start at 1KW then 10KW then 100KW...
The point is its much easier (I think) to construct higher power devices than to detect low thrust levels.
If a 1KW device was to slide down an air-track then the world would change...

OK I completely agree with you and JohnFornaro on that.  Now,

Does the Shawyer/SPR Ltd.'s device have a thrust orders of magnitude (400 to 4250 times higher) higher than Cannae device -as quoted by Dr. White- yes or not?  Did Dr. White's lab test the Shawyer/SPR Ltd.'s device, yes or not?

Can someone in this forum answer that, please  :)?

The copper Truncated Frustrum thingy looks like Shawyer's device.  Glad that you agree with me, BTW.

It would be nice to read more of Rodal's analysis of the testing mechanism.

The theory of how this device works is changing.  Here's some forum history:

<a href="http://forum.nasaspaceflight.com/index.php?topic=13020.msg392562#msg392562">Quote from: Star-Drive on 04/18/2009 06:35 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=13020.msg392499#msg392499">Quote from: Nathan on 04/18/2009 02:36 PM</a>
Quote
Quote

EM-Drive is not fake science. They have a WORKING prototype and are moving towards a flight test in 2009. www.emdrive.com. This uses actual physics and obeys all the convervation laws.

I am NOT impressed by this site.  It states that just like a laser ring gyro is a closed system and can measure rotation rate, this drive is a closed system that can produce force.  Newton and all have NO problem with a closed system measuring rotation rate.  No need to introduce Special Theory effects to explain this.  Explaining away the closed system problem by using the laser ring gyro as an analogy tells me these people are incorrect.

However I do hope I am wrong and they produce a really nice rocket engine someday.  I for one will not be investing my money in this technology.

Danny Deger

P.S.  Maybe there is some change of momentum of the photons that balances the change of momentum of the rocket.  This would make the device not violate the law of the conservation of momentum.

I took me a while to understand how it works. There is a basic property of a waveguide that describes how the group velocity of a wave changes as the size of the waveguide changes. For the em-drive it is this that creates the force imbalance on the end walls of the cavity. In terms of momentum, if there are two equal masses and the total momentum p=p1-p2 then p is non zero when the velocities of the particle colliding at each end of the waveguide differ. The slope of the walls of the cavity ensure the collisions with the walls along the length result in a nonlinear force ie: the differing group velocities along the length of the sloping cavity ensure the particles don't just bounce around inside the cavity canceling each others forces totally out. One uses the law of relativistic velocity addition to see that there is forward motion when the thruster is viewed by an outside observer (thus an open system).

To illustrate:

If one fires two opposing canons within a closed box the impact of the canonballs against the walls will cancel out to result in zero motion. If either the velocity or the mass of one of the balls changes en-route to the wall then the impacts will not cancel out and there will be motion. The trick then is to deal with the lost mass or velocity. It has to have gone somewhere.

From the point of view of momentum; The em-drive looks at the change in velocity whereas the woodward drive looks at the change in mass. The both deal with the imbalance in different ways. EM-drive uses the properties of waveguides and relativity whereas woodward's drive uses machian mass fluctuations and a rectifier.

When one accounts for the energy absorbed into the system to create the motion then one retains conversation of energy. Same for momentum.

So I think I understand. Took me a while but I think I'm there. And it is basic physics! It USES newton laws. It just needed a different perspective.


Nathan:

A major problem with Shawyer’s waveguide explanation is that his theoretical proof does not provide an explanation for the magnitude of the reaction forces reported.  Photon rockets of any stripe with only several hundred watts of input power can't generate thrusts measured in milli-Newtons.  Instead they can only produce pico to nano-Newtons of thrust from their local power supplies, unless they are also inadvertently tapping into a higher dimensional energy manifold as do Woodward's devices with the cosmologically derived gravinertial field. 

However, Shawyer first has to replicate his posted video experiment in a hard vacuum (<1x10-6 Torr) and get the same results, thus precluding possible ion wind or cooling fan generated thrusts before we worry too much about his proposed theoretical approach.  If he does get the same reported thrust in a vacuum though, then my bet is still on Sonny White's QVF explanation being more accurate than Shawyer’s.

BTW, as noted by GI-Thruster, I need to find the time and resources to replicate my Mach-2MHz experiment and/or exercise my new MLT-2009 test article in a hard vacuum, before we can take its results to be anything more than strongly suggestive that M-E based MLTs work as advertised.  Alas, that next step for me has proven problematic so far...

What does the device push upon?  Personally, I'm disregarding the "free energy" aspect of the device, and am more concerned with the conservation of momentum.

<a href="http://forum.nasaspaceflight.com/index.php?topic=13020.msg393020#msg393020">Quote from: blazotron on 04/20/2009 08:46 AM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=13020.msg392311#msg392311">Quote from: mlorrey on 04/17/2009 09:24 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=13020.msg392301#msg392301">Quote from: gospacex on 04/17/2009 08:57 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=13020.msg391142#msg391142">Quote from: Star-Drive on 04/14/2009 07:14 PM</a>
So what do you consider “substance” in regards to proving these observed M-E effects are REAL?  Supporting experimental data from two or more different sources used to be considered substantiating support, but apparently that is no longer the case in 2009.  So what will it take to prove the point to you and the rest of the skeptics in the world that the M-E or its QVF cousin is real and usable?

I am not a sceptic, I would be *happy* if someone will prove that 3rd law of Newton can be worked around.

It can be the case that the idea, being rather radical, does require verification by more than one team. Extraordinary claims do require extraordinary evidence, in this case, reproduction of the effect by multiple teams.

Do not assume that "they" (meaning scientific community) have ill intentions. No amount of complaining that "they" don't take it seriously would help. Ony more independent verifications will.

Firstly, please stop asserting that M-E gets 'around' Newtons third law any more than a game of tug-of-war does. The M-E reacts against the rest of the universe, period. While I understand thats a bit big of a concept for some folks, honestly though, it shouldn't be for anybody who has moved beyond the idea that anything outside our solar system is just little light bulbs on a big sphere.

By what mechanism is it reacting against the rest of the universe?  Why do other devices not react with the rest of the universe like this?  Why is this one special?  How can it instantaneously signal the rest of the universe to react?  Saying it is so doesn't make it so.

I'm not explaining anything.  I'm trying to understand the concept here.  My earlier post about how the non-exhaustive list (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255287#msg1255287) simply does not serve to explain the theory still holds true.

Every year since around 2009, the theoretical rabbit hole of explanation about how this device works gets deeper and deeper, and thrust levels do not appear to be rising.

If there's a skunk works somewhere working on this, and it is Top Secret (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255303#msg1255303) then so be it.

Just for more reading, as well as an illustration of the Truncated Frustrum thingy.  The Chinese have expressed interest in this technology, and seem willing to invest:

http://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=1898

http://blog.wired.com/defense/2008/09/chinese-buildin.html

An earlier explanation of the EmDrive suggested that "group velocity" was an operating principle. From my post on that Propellantless Propulsion thread on April 21, 2009, 03:19:58 PM:

IAC- 08 – C4.4.7.  which I’ll call “The Theory Paper”.

Group velocity is the speed with which the modulation of the wave propagates through space.  It is not the speed which any particles propagate. It is here that the paper falls apart for me, and is precisely the point in the cannonball analogy above where the analogy falls apart.  All of the cannonballs’ momentii (if that’s the word) will cancel out, unless the mass of a cannonball changes.  Then the analogy can propel itself forward.  But there’s no explanation of what it is that changes about the cannonballs to provide momentum.

Group velocity is dw/dk, where w is the wave’s angular frequency and k is the wave number.  I don’t see how this affects momentum.

In blazotron’s analysis of the theory paper, he states: “Then [Shawyer] states, completely without support, that the force imparted by a wave with group velocity vg is 2nhfA*(vg/c).  Nowhere in the text is it explained why we should be using the group velocity of the wave to calculate force.”  I think blazeotron is somewhat incorrect in stating where in the text is this explained.  The author alludes to:

CULLEN A.L. ‘Absolute Power Measurements at Microwave Frequencies’ IEE proceedings Vol 99 Part IV 1952

Thanks to MikeGi:

More on Shawyer:

http://www.assassinationscience.com/johncostella/shawyerfraud.pdf

Note how Shawyer's "Theory" original paper:
http://www.newscientist.com/data/images/ns/av/shawyertheory.pdf

Differs from the "Theory" paper now on his website:

http://www.emdrive.com/theorypaper9-4.pdf

Thanks to my digging:

http://www.rexresearch.com/shawyer/shawyer.htm

http://www.rocketeers.co.uk/?q=node/330

EmDrive at work:

http://www.youtube.com/watch?v=57q3_aRiUXs

See also here:

http://forum.nasaspaceflight.com/index.php?topic=14423.0

Thanks to 93143:

http://www.emdrive.com/yang-juan-paper-2012.pdf

http://forum.nasaspaceflight.com/index.php?topic=13020.msg978642#msg978642

Finally:

<a href="http://forum.nasaspaceflight.com/index.php?topic=13020.msg979132#msg979132">Quote from: JohnFornaro on 11/14/2012 05:11 PM</a>
<a href="http://forum.nasaspaceflight.com/index.php?topic=13020.msg979109#msg979109">Quote from: aero on 11/14/2012 04:26 PM</a>
John - You're grasping at straws. The topic is Propellantless Field Propulsion and application. The test stand has no bearing on the topic beyond giving assurances that the thrust measurements were accurately made. Any good test stand will do, even a pendulum.

Aero: ...

The common wisdom is that EM drive does not work.  In the case of Woodward's work, and probably Shawyer's as well, the test stand is almost as important as the tested device itself, since the expected forces are thought to be very low in the experiments demonstrated.

Woodward and Paul March have gone to great lengths to account for spurious outside signals, and even now, can barely ascertain the output of his device from noise.

A pendulum will most assuredly not work.  ...  The measurement of the forces is key, until such time as they float one of these devices out on the conference room table. ...

The test stand is very important.  If I might repeat myself:  It would be nice to read more of Rodal's analysis of the testing mechanism.

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 02:47 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255539#msg1255539">Quote from: JohnFornaro on 09/15/2014 02:27 PM</a>
The test stand is very important.  If I might repeat myself:  It would be nice to read more of Rodal's analysis of the testing mechanism.

@JohnFornaro

I completely agree with your statement <<The test stand is very important. >>. There are pendulum dynamic forces to take into account, as well as nonlinear coupling between swinging and torsional modes of oscillation.  I started to discuss this in detail but the thread got deviated into controversial-theoretical explanations.  Paul March was forthcoming with data.  My last post dealing with the test stand, I made some calculations (stiffness and natural frequency of swinging mode) based on my interpretation and I asked for confirmation.  There have been so many posts dealing with controversial-theoretical explanations that that particular post got buried  :).  Perhaps I should re-post it. 

My plan is the following: once Paul March has a chance to look at it, and to verify my understanding, then I can proceed to show my transformation of axes (rigid-body axes for the drive supported on the inverted pendulum compared to the fixed suport axes located at the bottom support of the inverted pendulum arm), and then my computation of a Lagrangian, and then the resulting equations of motion (showing coupling of torsion with swinging modes, and parasitic motions) from differentiating the Lagrangian....

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 03:24 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255539#msg1255539">Quote from: JohnFornaro on 09/15/2014 02:27 PM</a>

Quote

...Newton and all have NO problem with a closed system measuring rotation rate.  ...
Danny Deger


Excellent point by Danny.  I agree.  Feynman has a trick question regarding conservation of momentum (on the rotational effect of an electromagnetic force) on his Lectures on Physics classic.

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 03:30 PM
To put this in fewer words:

If the drive's support platform (sitting on the inverted pendulum) does not stay horizontal when the inverted pendulum arm swings off-center, then this might be a problem, as it leads to coupling of swinging and torsional modes, and therefore to parasitic modes.  That's why Prof. Martinez-Sanchez at MIT designed (with students for their S.M. theses) his inverted pendulum's stand to stay horizontal at all times, even for swinging off-center motion of the inverted pendulum arm.
Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 05:50 PM
Referring to the following Paul March's article http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=31119.0;attach=496011

It is clear that

A) the "2004 Test Article" and the "2005 Test Campaign" referred to in slide 40 of Dr. White's presentation http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf ) are exactly the same as Paul March's tested devices in 2004 and 2005 in (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=31119.0;attach=496011)

B) the "2004 Test Article" and the "2005 Test Campaign" referred to in slide 40 of Dr. White's presentation http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf ) were NOT tested in Dr. White's NASA inverted torsion pendulum.  Instead they were tested by Paul March using a load cell.

Since it also appears that the Shawyer/SPR Ltd. data labeled as "Microwave Thruster Device" in slide 40 of Dr. White's presentation http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140000851.pdf ) were NOT tested in Dr. White's NASA inverted torsion pendulum, but instead they were tested elsewhere, we must separate the performance of devices tested elsewhere from those tested with Dr. White's NASA inverted torsion pendulum as follows:

Experimental data not obtained using Dr. White's NASA inverted torsion pendulum

______________________________

Shawyer/SPR Ltd.'s microwave device:

THRUST =  16000 to 170000 uN
SPECIFIC FORCE = 0.02 to 0.4 N/kW

______________________________

Paul March Woodward-Effect device tested in 2004:   

THRUST = 4000 uN
SPECIFIC FORCE=  0.4 N/kW

______________________________

Paul March Woodward-Effect device tested in 2005: 

THRUST = 3000 uN
SPECIFIC FORCE=  0.3 N/kW

______________________________
******************************
Experimental data obtained using Dr. White's NASA inverted torsion pendulum


Boeing/DARPA device:

THRUST =   20 to 110 uN 
SPECIFIC FORCE = 1 to 20 N/kW

______________________________

Cannae Testing:

THRUST =   40 uN
SPECIFIC FORCE:  0.0014 N/kW
______________________________

Tapered (Frustum) Cavity Testing: 

THRUST = 50 to 90 uN
SPECIFIC FORCE=  0.003 N/kW to 0.0054 N/kW

______________________________

It is evident from the above:

A) The thrust force measurements performed elsewhere are 33 to 8500 times greater than the thrust measurements using Dr. White's inverted torsion pendulum experiments.

B) It is interesting that different devices (Boeing/DARPA compared to the microwave devices) although they have specific forces differing by a large factor of 1000 times, have approximately the same thrust force measurements in Dr. White's inverted torsion pendulum.

If we have to ignore the very high thrust forces of the Shawyer/SPR Ltd because those numbers are untrustworthy (not from NASA), and if we have to ignore the very high specific force of the Boeing/DARPA device because its thrust force was not a rectangular pulse, but instead an impulse and hence not suitable for steady-state operation, the clear winner both in thrust force and specific force are the  Woodward-Effect devices, they have orders of magnitude greater thrust force and specific force than the lousy-performing Cannae and Frustum (Tapered Cavity) devices recently tested.

However:

Paul March's Woodward-Effect devices were tested in a completely different set-up (using a load cell instead of an inverted torsion pendulum).
Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 05:59 PM
a riddle wrapped in a mystery inside an enigma

Since Paul March's Woodward-Effect tests show thrust forces and specific forces two orders of magnitude larger than those measured for the Cannae and the Frustum (Tapered Cavity) microwave devices,

Why haven't  Paul March's Woodward-Effect devices been tested in NASA/Dr. White's Eagleworks inverted torque pendulum and reported?

Wouldn't they have served as an independent control purpose of the measurements?  It would have been helpful to have the same device (Paul March's) tested in two different testing set-ups (in inverted torsion pendulum to compare with the previous load cell measurements )
Title: Re: EM Drive Developments
Post by: aero on 09/15/2014 06:07 PM

Quote
Paul March's Woodward-Effect devices were tested in a completely different set-up (using a load cell instead of an inverted torsion pendulum).

Maybe Paul March would test the Tapered (Frustum) Cavity using his set-up. That should also work to provide valid comparison between the two devices.

Title: Re: EM Drive Developments
Post by: Rodal on 09/15/2014 06:49 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255626#msg1255626">Quote from: aero on 09/15/2014 06:07 PM</a>
Quote
Paul March's Woodward-Effect devices were tested in a completely different set-up (using a load cell instead of an inverted torsion pendulum).

Maybe Paul March would test the Tapered (Frustum) Cavity using his set-up. That should also work to provide valid comparison between the two devices.

There is also a need to verify the reliability of the much publicized measurements already conducted with NASA's Eagleworks inverted torsion pendulum.  A NASA measurement carries a prestige (in the media) much higher than a measurement conducted at other places.  Three different devices (Boeing/DARPA, Cannae and Frustum), that have specific forces differing by a factor of 1000 give approximately the same experimental measurement range of thrust force.  A control is needed.  Paul March's previously load-cell-tested Woodward-Effect devices would serve as such a control for the thrust measurements.   If Paul March's measurements would be independently verified at NASA that would also carry significant prestige for Dr. Woodward's long-running efforts.

Title: Re: EM Drive Developments
Post by: JPLeRouzic on 09/15/2014 06:56 PM

<a href="http://forum.nasaspaceflight.com/index.php?topic=29276.msg1255621#msg1255621">Quote from: Rodal on 09/15/2014 05:59 PM</a>

Why haven't  Paul March's Woodward-Effect devices been tested in NASA/Dr. White's Eagleworks inverted torque pendulum and reported?

@Rodal: My feeling is that you try to find too much meaning in this whole thing. After all, there is no scientific or engineering breakthrough described in the Dr White paper, just a report on some exotic experimentations with anomalous results. I see it as some "food for thought" paper. Indeed as Pa