Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1795401 times)

Offline deltaMass

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This is useful for those still arguing over group vs phase velocity.

http://www-math.mit.edu/~stevenj/papers/PovinelliIb04.pdf

Slow-light enhancement of radiation pressure
in an omnidirectional-reflector waveguide.
What does this paper confirm for you?

Offline OttO

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It doesn't matter if there is a more momentum at one vs the other. This theory of operation will not result in the frustum moving because....

The small end and the large end are physically connected, so the total momentum is ZERO.

Yep, but if like me you fear that it is only a fan then near field radiative momentum could be an explanation.
In a way it would be a new kind of ... lifter  ;)

Offline Mulletron

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This is useful for those still arguing over group vs phase velocity.

http://www-math.mit.edu/~stevenj/papers/PovinelliIb04.pdf

Slow-light enhancement of radiation pressure
in an omnidirectional-reflector waveguide.
What does this paper confirm for you?

Two things:

1) Every time someone mentions "phase velocity" within a waveguide, a cute bunny gets it.
2) Using TE01X modes as the model, the radiation pressure per unit area is greatest at the small end where Vg is slowest (not the other way around).

@ElizabethGreene mentioned #2 a few days ago here, but for different reasons:

http://forum.nasaspaceflight.com/index.php?topic=37642.msg1407704#msg1407704
« Last Edit: 08/07/2015 12:00 PM by Mulletron »
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Online Rodal

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Any way, whether using 30 degrees or 30.0412 degrees this geometry is going to resonate at TE012 at a lower natural frequency than the 2.45 GHz TheTraveller calculated.

So what do your exact solutions give for each value of the possible angles we found (30 and 30.0412) for TE012 and TE013? Are they really different with such a slight difference?

I think TheTraveller may have accounted for that lower natural frequency, as he also noted on his drawing: "Min operational frequency 2.3 GHz".
Given his announced commercial (licensing) relationship with Shawyer and  unwillingness to consider anything that deviates from what is prescribed by Shawyer, it has become apparent that it is a waste of my time to spend any further time discussing anything related to TheTraveller. 

I have also arrived at the conclusion that I cannot trust any experimental claims that TheTraveller may present.

I look forward to the experiments of rfmwguy and SeeShells and hopefully to any further news from NASA Eagleworks and Tajmar.
« Last Edit: 08/07/2015 12:18 PM by Rodal »

Offline TheTraveller

2) Using TE01X modes as the model, the radiation pressure per unit area is greatest at the small end where Vg is slowest (not the other way around).

At the small end, the guide wavelength is the longest, the group velocity is the slowest and the radiation pressure is the smallest. Power per end plate area is the same at each end plate.

As example see the attached, which is from my latest frustum design.
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Offline TheTraveller

I have also arrived at the conclusion that I cannot trust any experimental claims that TheTraveller may present.

Seems the way you handle being shown you are incorrect is to stick your head in the sand?

Good luck with that.
« Last Edit: 08/07/2015 12:24 PM by TheTraveller »
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Offline Mulletron

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2) Using TE01X modes as the model, the radiation pressure per unit area is greatest at the small end where Vg is slowest (not the other way around).

At the small end, the guide wavelength is the longest, the group velocity is the slowest and the radiation pressure is the smallest. Power per end plate area is the same at each end plate.

As example see the attached, which is from my latest frustum design.

Shawyer has been wrong before. At least others think so. Is it possible he has it backwards?
Challenge your preconceptions, or they will challenge you. - Velik

Offline TheTraveller

2) Using TE01X modes as the model, the radiation pressure per unit area is greatest at the small end where Vg is slowest (not the other way around).

At the small end, the guide wavelength is the longest, the group velocity is the slowest and the radiation pressure is the smallest. Power per end plate area is the same at each end plate.

As example see the attached, which is from my latest frustum design.

Shawyer has been wrong before. At least others think so. Is it possible he has it backwards?

Backward?

That data is based on microwave industry equations and Cullen 15 for the radiation pressure on the end plate bounce Force / momentum transfer per bounce.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
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Offline rfmwguy

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Any way, whether using 30 degrees or 30.0412 degrees this geometry is going to resonate at TE012 at a lower natural frequency than the 2.45 GHz TheTraveller calculated.

So what do your exact solutions give for each value of the possible angles we found (30 and 30.0412) for TE012 and TE013? Are they really different with such a slight difference?

I think TheTraveller may have accounted for that lower natural frequency, as he also noted on his drawing: "Min operational frequency 2.3 GHz".
Given his announced commercial (licensing) relationship with Shawyer and  unwillingness to consider anything that deviates from what is prescribed by Shawyer, it has become apparent that it is a waste of my time to spend any further time discussing anything related to TheTraveller. 

I have also arrived at the conclusion that I cannot trust any experimental claims that TheTraveller may present.

I look forward to the experiments of rfmwguy and SeeShells and hopefully to any further news from NASA Eagleworks and Tajmar.
Doc,

Guess Mr T is either Shawyer himself or has developed an unshakeable belief system based on nothing other than what he has learned from afar. Repetition of SPR data is not helpful, imo, most of us have seen the same charts and pics ad nauseum. I would go so far as to suggest mod intervention to limit excessive bandwidth taken by these attachments.

Here's the bottom line: Its interesting enough to experiment with and there is no entity out there that has convinced me enough to believe in it just by their words or videos. If one believes someone without exception, that person should not theorize, experiment or even post here...whats the point other than trying to elicit group think.

<end micro-rant>

NSF-1700 update - cam test and live chat tonight if all goes well. Frustum has Db of a spherical mesh only. Will have it on cam for a close, higher quality video. That way, you can see all the build imperfections ;)

Online Flyby

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Given his announced commercial (licensing) relationship with Shawyer and  unwillingness to consider anything that deviates from what is prescribed by Shawyer, it has become apparent that it is a waste of my time to spend any further time discussing anything related to TheTraveller. 

I have also arrived at the conclusion that I cannot trust any experimental claims that TheTraveller may present.

I look forward to the experiments of rfmwguy and SeeShells and hopefully to any further news from NASA Eagleworks and Tajmar.

I'm not here to defend TT, but I find that a regretful attitude.... :(
 
Whatever experiment TT does, due to his great similarity with what Shawyer did in the past, it will help to assess if Shawyer's experiments hold any value or not.
At least, in contrast with Shawyer, TT promised total transparency on his approach. That will make it much easier to follow the experiment and draw conclusions from it.

So, in that respect TT's experiment remains valuable, regardless of the huge clash of opinion you both have...

I'm looking forward to ALL the experiments, not just a few of them...
Even from the baby EMdrive, we could draw some conclusions that can be useful for future experiments.

I don't see the point to start bickering over experiments that have not taken place yet...?
Good experiments, bad experiments, failures.. you need it all to make progress when you're into uncharted territory...
« Last Edit: 08/07/2015 03:38 PM by Flyby »

Offline WarpTech

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...
I played with the numbers yesterday for F=2P/Vg -> F=2*P*Sqrt(1-(c/(2*(a+x)*f))^2) and found ...
...
Disclaiming again, I probably broke the math.

The equation would be F = (Vg/c^2)*P = P/Vp. IF you use standard waveguide physics that is. In the case of the EM Drive, this may be, F = (Vg*K/c^2)*P, where K is a function TBD by experiment.
Todd

If F=P/Vp is correct for traditional physics, then Mr. Shawyer's theory falls apart.  Specifically, as the size of the waveguide decreases Vp increases.  An increase in Vp decreases F.  That would make the force on the little end --smaller-- than the force on the big end.

Is that right?

Pretty much... It is that the momentum of an EM wave depends on the phase velocity and Planck's constant. It is the phase velocity, Vp = w/k that give us the momentum per photon, p=h*k. So if Vp is increasing, p is decreasing, and if Vp is decreasing, p is increasing. Either way, the force on the frustum is in the same direction in order to conserve momentum. The momentum is "forward rectified" by the gradient. It is only the reflection at the big end that is opposing this force. Anything that reduces the force on the big end, will result in forward thrust.

In order for the big end to 100% cancel these forces, the force on the big end would have to be larger than the force at the small end. Definitely not smaller. If it is smaller by hook or by crook, or by leakage or heat, then the frustum will feel a thrust forward.

The real question is still, how does it get thrust greater than a photon rocket? I see 3 possibilities:

1. A group velocity that is faster than light in free space.
2. A phase velocity that is slower than light in free space.
3. A means to change the speed of light such that Vg*Vp = (c/K)2, in which case the group velocity could be faster than light in a frustum, but slower than light in free space and result in an amplified ratio;

Vg/c2 -> K*Vg/c2, where K > 1

This way, nothing ever exceeds c in free space, but it reduces both the phase velocity and the group velocity to be much less than c. It is consistent with the PV Model of gravity. I just don't know how to derive it yet. I have 2 key pieces to the puzzle. Squeezed light behaves this way, and what Zeng and Fan show for an impedance curve looks almost exactly like a Reissner Nordstrom "charged" metric refractive index. Somehow, this all seems to make sense to me, but not well enough to write down the correct equations.
Todd
 

Why do you and others keep referring to phase velocity inside a waveguide as it is above c. Inside a waveguide energy moves at group velocity, which is determined from the guide wavelength, which is determined from the cutoff wavelength. The momentum in the wave varies as the guide wavelength varies, longer at the small end and shorter at the big end.

http://www.microwaves101.com/encyclopedias/waveguide-mathematics#velocity

Cullen 15, attached, is based on this and proved that it is correct, so please stop talking above phase velocity inside a waveguide as it is above c and nothing travels above c.

Lambda/lambda_g*c = 1/Vp  Mr. T. It is "You" who prefer to use the term Guide Wavelength. I prefer to use the term Phase Velocity. The resulting equation is identical. It is a matter of preference, not mathematics.

F = 2*P/Vp = 2*P*lambda/lambda_g*c

Call it what you like, but phase velocity is what it "is".
Todd
« Last Edit: 08/07/2015 01:43 PM by WarpTech »

Offline Mulletron

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It doesn't matter anyway what the radiation pressure is at either end. Even if there are unbalanced forces at each end, internal to the frustum, it isn't going to move.

This is central to why everyone (mostly celebrity scientists and the media) is saying this thing violates COM.

I recommend we get rid of any theory that features unbalanced forces at the large/small end and focus on what we recently learned from @Aero and @Rodal that there is a net (and increasing) Poynting vector*.

* http://forum.nasaspaceflight.com/index.php?topic=37642.msg1401370#msg1401370
« Last Edit: 08/07/2015 02:19 PM by Mulletron »
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Online Rodal

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It doesn't matter anyway what the radiation pressure is at either end. Even if there are unbalanced forces at each end, internal to the frustum, it isn't going to move.

This is central to why everyone (mostly celebrity scientists and the media) is saying this thing violates COM.

I recommend we get rid of any theory that features unbalanced forces at the large/small end and focus on what we recently learned from @Aero and @Rodal that there is a net (and increasing) Poynting vector.
We have a great opportunity to understand what is going on in the near future because we have two very trustworthy people working on independent objective tests (rfmwguy and SeeShells).   It is a very unusual opportunity because (just as we did for a while with Paul March at NASA) both rfmwguy and SeeShells are active in this thread.   Their approach to testing is unbiased and objective.  Unlike what happened with NASA we are under no threat of the communication being interrupted, and unlike what happened with Iulian they are active in the thread and we are under no threat of rfmwguy or SeeShells suddenly stopping their experiments.

PS: coincidentally, I had also been looking to friction as well.  To be explicit: related to the boundary conditions between air and the frustum and between the electromagnetic field and the frustum.


Offline TheTraveller

Lambda/lambda_g*c = 1/Vp  Mr. T. It is "You" who prefer to use the term Guide Wavelength. I prefer to use the term Phase Velocity. The resulting equation is identical. It is a matter of preference, not mathematics.

F = 2*P/Vp = 2*P*lambda/lambda_g*c

Call it what you like, but phase velocity is what it "is".
Todd

Energy in a waveguide moves at group velocity, which is slower than c. By microwave industry convention, phase velocity in a waveguide is the above c and imaginary.

http://www.microwaves101.com/encyclopedias/waveguide-mathematics#velocity

The 2 are related by group velocity x phase velocity = c2

So the term for energy transport inside a waveguide is group velocity and not phase velocity. Guide wavelength is the other side of the same coin. So inside a waveguide the guide wavelength is what it is and the group velocity is the velocity the guide wavelength and energy moves at.
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Offline Mulletron

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It doesn't matter anyway what the radiation pressure is at either end. Even if there are unbalanced forces at each end, internal to the frustum, it isn't going to move.

This is central to why everyone (mostly celebrity scientists and the media) is saying this thing violates COM.

I recommend we get rid of any theory that features unbalanced forces at the large/small end and focus on what we recently learned from @Aero and @Rodal that there is a net (and increasing) Poynting vector.
We have a great opportunity to understand what is going on in the near future because we have two very trustworthy people working on independent objective tests (rfmwguy and SeeShells).   It is a very unusual opportunity because (just as we did for a while with Paul March at NASA) both rfmwguy and SeeShells are active in this thread.   Their approach to testing is unbiased and objective.  Unlike what happened with NASA we are under no threat of the communication being interrupted, and unlike what happened with Iulian they are active in the thread and we are under no threat of rfmwguy or SeeShells suddenly stopping their experiments.

PS: coincidentally, I had also been looking to friction as well.  To be explicit: related to the boundary conditions between air and the frustum and between the electromagnetic field and the frustum.

Yeah true. I have a frustum too and about a thousand dollars invested so far on everything, but there for a while I got so burned out on this that I had to take a break. That combined with all the "anti West" comments from Shawyer in the media, I simply ran out of _'s.

I'm slowly getting back in the game again. I really need to find a cheap USB signal generator.

@TT. I really need you to question everything here. I don't want to see you loose cred by being viewed as a fanboy and not a scientist. Find the truth on your own, don't let the truth be revealed to you.

I mean, if EMdrive does in fact work, then Shawyer is a hero and deserves credit for it. But there is likely a reason this thing has been stagnant for so long, he could have gotten things wrong too.
« Last Edit: 08/07/2015 02:34 PM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Offline TheTraveller

It doesn't matter anyway what the radiation pressure is at either end. Even if there are unbalanced forces at each end, internal to the frustum, it isn't going to move.

This is central to why everyone (mostly celebrity scientists and the media) is saying this thing violates COM.

I recommend we get rid of any theory that features unbalanced forces at the large/small end and focus on what we recently learned from @Aero and @Rodal that there is a net (and increasing) Poynting vector*.

* http://forum.nasaspaceflight.com/index.php?topic=37642.msg1401370#msg1401370

The momentum loss to the internal EM wave is balanced by the momentum gained by the external frustum, so CofM is maintained. Why is that hard to understand? It is a balanced momentum transfer.

Inside the frustum there are 4 momentum reactions:

1) Small end plate bounce of the longer EM wavelength with smaller momentum and smaller opposite but equal Force on the Frustum toward the big end.

2) Large end plate bounce of the shorter EM wavelength with larger momentum and larger opposite but equal Force on the frustum toward the small end.

3) Momentum EM wave gain as the EM wave propagates small end to big end with an opposite but equal momentum Force on the frustum toward the small end. (rocket like effect)

4) Momentum Em wave loss as the EM wave propagates big end to small end with a Force on the frustum toward the small end. (downwind sail like effect)

Shawyer has shown cases 1 and 2 balance out and do not generate any external Force as attached.

What cases 1 and 2 do is to set up the conditions for cases 3 and 4 to exist and transfer EM wave momentum to the frustum.

The lost internal EM wave momentum is balanced by the external frustum's gained momentum, so CofM is conserved as both Shawyer and Prof Yang claimed.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
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Offline TheTraveller

It doesn't matter anyway what the radiation pressure is at either end. Even if there are unbalanced forces at each end, internal to the frustum, it isn't going to move.

This is central to why everyone (mostly celebrity scientists and the media) is saying this thing violates COM.

I recommend we get rid of any theory that features unbalanced forces at the large/small end and focus on what we recently learned from @Aero and @Rodal that there is a net (and increasing) Poynting vector.
We have a great opportunity to understand what is going on in the near future because we have two very trustworthy people working on independent objective tests (rfmwguy and SeeShells).   It is a very unusual opportunity because (just as we did for a while with Paul March at NASA) both rfmwguy and SeeShells are active in this thread.   Their approach to testing is unbiased and objective.  Unlike what happened with NASA we are under no threat of the communication being interrupted, and unlike what happened with Iulian they are active in the thread and we are under no threat of rfmwguy or SeeShells suddenly stopping their experiments.

PS: coincidentally, I had also been looking to friction as well.  To be explicit: related to the boundary conditions between air and the frustum and between the electromagnetic field and the frustum.

Yeah true. I have a frustum too and about a thousand dollars invested so far on everything, but there for a while I got so burned out on this that I had to take a break. That combined with all the "anti West" comments from Shawyer in the media, I simply ran out of _'s.

I'm slowly getting back in the game again. I really need to find a cheap USB signal generator.

@TT. I really need you to question everything here. I don't want to see you loose cred by being viewed as a fanboy and not a scientist. Find the truth on your own, don't let the truth be revealed to you.

I mean, if EMdrive does in fact work, then Shawyer is a hero and deserves credit for it. But there is likely a reason this thing has been stagnant for so long, he could have gotten things wrong too.

I'm no fan boy. Was an EMDrive agnostic then did my research. I followed the data and put together my own spreadsheet to predict various elements of EMDrive data and see how it matched the experimental data. What I saw convinced me I was seeing the results of a real device with real operational characteristics.

This is no different to what happened to Ponds and Fleishman. Even today with 100s of replications and peer reviewed papers, Cold Fusion is still called junk science by established science, despite this 2009 tally of research papers:

http://lenr-canr.org/acrobat/RothwellJtallyofcol.pdf

We how have 6 EMDrive peer reviewed papers, positive published results from Shawyer, Prof Yang, Eagleworks & Prof Tajmar yet still it is denied the EMDrive can work as claimed. Why? Just maybe some have dug a very deep hole for themselves.

All that is really happening is Shawyer has discovered a way to convert some internal EM wave momentum into external frustum momentum, yet for most believing that is possible is a "bridge too far", even though the momentum lost to the EM wave is exactly the momentum gained by the frustum.
« Last Edit: 08/07/2015 03:04 PM by TheTraveller »
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Offline SeeShells

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Theories. They abound and we're at what? Close to a dozen right now? the way I see it each and every one has its good points and bad and if you're here to discover the truth you can't strap yourself to just one. You might be eating your hat.

I have my favorite but that cannot and will not detract or bias me in finding the why. The only real data that is true is mother natures and she trumps and belittles us all, she wrote the book we can barely read.

I've been quite surprised by the simulations in meep and even though meep has it's limits it's enough to allow me to setup several testing criteria to test for different data. One is if this was a normal waveguide or resonant chamber you would expect a stable mode generation and a clean traveling wave locked into Q or traveling down the wave guide. This hasn't been the case. Because of the frustum's variable geometry I see in just a short run for a few cycles in meep mode changes and decays up and down the frustum.

Can anyone explain to me when I see a mode shift in the meep time slices the time it seems to happen... it's within the meep data sample rate. The modes shift from top to bottom or side to side and if actions within the cavity still obey basic laws how can I see a full mode shift top to bottom in less than 1 ns (from sample rate to sample rate which is 1/10th of a cycle?) Light and most actions travels about ~11 inches in 1 ns. I'm so trying to gork opps grok this. I guess I need someone to give me a primmer.

Shell

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Theories. They abound and we're at what? Close to a dozen right now? the way I see it each and every one has its good points and bad and if you're here to discover the truth you can't strap yourself to just one. You might be eating your hat.

I have my favorite but that cannot and will not detract or bias me in finding the why. The only real data that is true is mother natures and she trumps and belittles us all, she wrote the book we can barely read.

I've been quite surprised by the simulations in meep and even though meep has it's limits it's enough to allow me to setup several testing criteria to test for different data. One is if this was a normal waveguide or resonant chamber you would expect a stable mode generation and a clean traveling wave locked into Q or traveling down the wave guide. This hasn't been the case. Because of the frustum's variable geometry I see in just a short run for a few cycles in meep mode changes and decays up and down the frustum.

Can anyone explain to me when I see a mode shift in the meep time slices the time it seems to happen... it's within the meep data sample rate. The modes shift from top to bottom or side to side and if actions within the cavity still obey basic laws how can I see a full mode shift top to bottom in less than 1 ns (from sample rate to sample rate which is 1/10th of a cycle?) Light and most actions travels about ~11 inches in 1 ns. I'm so trying to gork opps grok this. I guess I need someone to give me a primmer.

Shell

Same thing happens in dynamic structural response, for example in earthquake analysis or the dynamic response of a rocket during lift-off  https://en.wikipedia.org/wiki/Structural_dynamics#Modal_participation_factor.

Think of the response of a structure to an earhtquake, or the dynamic response of a rocket during the initial lift-off.



The whole concept of "modal response" analysis is a simplification to real response that involves a variety of modes.  For linear response one can describe a so called mode participation factor.

The difference between Meep and a closed-form solution is that Meep is NOT conducting a modal response.  Actually there are no explicit things as "evanescent waves", "travelling waves" or "standing waves", "group velocity" or "phase velocity" in Meep's solution method.  All there is in Meep are fields vs time.  The meaning of the the response has to be analyzed and is not obvious.   Meep is solving Maxwell's equations using the finite difference method.    To put the solution in terms familiar like "modes" for example requires achieving something approaching steady state that has not been achieved in the very short-time response being analyzed (less than 0.01 microseconds as I recall). 

The Meep solution so far should be interpreted as a transient response, not as a steady-state response.
« Last Edit: 08/07/2015 03:51 PM by Rodal »

Online Flyby

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We how have 6 EMDrive peer reviewed papers, positive published results from Shawyer, Prof Yang, Eagleworks & Prof Tajmar yet still it is denied the EMDrive can work as claimed. Why? Just maybe some have dug a very deep hole for themselves.

All that is really happening is Shawyer has discovered a way to convert some internal EM wave momentum into external frustum momentum, yet for most believing that is possible is a "bridge too far", even though the momentum lost to the EM wave is exactly the momentum gained by the frustum.
Let's tune down the overly optimistic tone a bit to see the things as they are...

Shawyer has produced the most "perceptible " evidence of a working EMdrive so far. By this I mean that he really build a functional demonstrator. However, there is - litterly- more then the eye can see and perception can be deceptive. The lack of controlled environment and the rather limited data available leaves a lot of questions unanswered, to a point it is not hard to question the validity of the test, for hardcore scientists. Us, laymen, may be easily impressed, but these guys are not....

Yang has the unfortunate situation to be Chinese, and as a consequence is suffering from Western view biased position as being "unreliable"... Personally, I see no reason to doubt Dr Yang competence or her equipment. Although she provides more test data then we got from Shawyer, it is highly probable her research caught the interest of the military, which limits her ability to speak. It needs a jump of faith to believe her data as we know almost nothing about the environmental setup of the experiment. We don't even have the right dimensions. And that's really basic info, needed to evaluate whether her test hold truth. No wonder people doubt the results...

EagleWorks tests had a problem to rise far enough above the measurement noise to be conclusive.
Their tests showed promise but did not provide rock solid material. They have decided to increase power on a new test setup, one that was scheduled for begin july.... We're 1 month further down the road, with zero information.

Prof Tajmar could neither confirm , nor deny whether an EMdrive works and promised to continue  the work.

If you add all this together, I would concluded that there are interesting indications that an EMdrive might work, but the margin of error and doubt is still way too big to be conclusively positive.

After all these years, it is still a "maybe"...

Perception is a powerful persuader, so Shawyer's video of the rotating table, makes me really want to believe, but as several clever people inhere already demonstrated, the rotating force may also be attributed to other influences. And as long that is not cleared up, our rationality must prevail our perception...

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