Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1804154 times)

Offline SeeShells

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Shell

I'll be the first to admit there is something going on and it deserves further testing.  I have never advocated, and never will, that testing should be abandoned.  However, I have always been clear that I feel the likelihood that that something is propellantless thrust to be very low.  Finding the exact quirk that gives the appearance of propellantless thrust is a worthwhile scientific endeavor in it's own right though.

Quote
I believe there is enough empirical data in such widely varying test beds and that this is just enough out of the noise of chance that there is something going on and it deserves further testing.

This right here is probably where you and I, and everyone else who has a different take on the emdrive from 100% likelihood to 0% likelihood, differ.  When the emdrive first popped back into the news last august, I always heard the word replication being thrown around.  Nasa has replicated a propellantless drive!  It was replicated by the Chinese!  UK inventor has drive replicated by Nasa and Chinese Labs!  These were the kinds of headlines I saw.  However, when you actually read through the individual papers, something practically explodes out at you.  None of the experiments are actually replications of any of the others:

The chinese got higher thrust from lower Q than Shawyer - goes against Shaywer's theory

Nasa didn't get thrust from a frustum without a dielectric - goes against Chinese and Shawyer's experimental results, goes against Shawyers theory.

Shawyer has gotten different thrust directions from different set-ups (dielectric vs. none) - goes against theory, just outright strange

So far, every experiment has used a drastically different apparatus, with different variable inputs and gotten massively different results.  Thrust direction has not even remained constant.  So when you look at the experiments in that light, the empirical data becomes rather sketchy.  To date, as far as I know, no lab has truly replicated any other, and that's a problem.

Edit:  A problem that may be be solved by all the DIY yourself projects that are coming online this month.  I may have to retire this criticism in a few weeks if strong data comes out of some of the replication attempts.
Degrasse Tyson sumed my work philosophy in Cosmos Unafraid of The Dark.
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No idea is true just because someone says so, including me.
Think for yourself.
Question yourself.
Don't believe anything just because you want to.
Believing something doesn't make it so.
Test ideas by the evidence gained from observation and experiment.
If a favorite idea fails a well-designed test, it's wrong! Get over it.
Follow the evidence, wherever it leads.
If you have no evidence, reserve judgment.
And perhaps the most important rule of all Remember, you could be wrong.
Even the best scientists have been wrong about some things.
Newton, Einstein, and every other great scientist in history, they all made mistakes.
Of course they did-- they were human."

Offline deltaMass

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http://physics.stackexchange.com/questions/190018/does-radiation-force-depend-on-group-velocity-or-on-phase-velocity

The answer is phase velocity

Therefore any explanations for thrust (like Shawyer's for example) which are based on a difference between group velocities, are just plain wrong.
« Last Edit: 07/05/2015 04:00 AM by deltaMass »

Offline TheTraveller

http://physics.stackexchange.com/questions/190018/does-radiation-force-depend-on-group-velocity-or-on-phase-velocity

The answer is phase velocity

Therefore any explanations for thrust (like Shawyer's for example) which are based on a difference between group velocities, are just plain wrong.

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

Inside a waveguide, the wave travels at group velocity and not at phase velocity which would be faster than c.

Shawyer is correct to model end plate forces based on end plate group velocity, which is related to guide wavelength as per the attached.

Any text on waveguides will tell you the energy in the waveguide propogates down the waveguide at group velocity speed.
« Last Edit: 07/05/2015 04:34 AM by TheTraveller »
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Offline WarpTech

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This guys think another way

http://arxiv.org/abs/0708.3519

:)

...
This is where I'm at... The attached image is the derivation of the Photon Rocket equation, for an open-ended circular waveguide. So anyone who says a photon rocket can only exert a maximum force of F = 2P/c, is only correct in free space but not when confined to a waveguide. The thrust-to-power ratio is much, much larger near the cut-off.

I tried his approach first, it only leads to a relativistic particle treatment of photons, but nothing more than the equivalent to a photon rocket. In my equation the added thrust comes from the M(z)*dz/z term. Which is a force due to the gradient in a potential caused by the cone geometry.
Todd

Offline WarpTech

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http://physics.stackexchange.com/questions/190018/does-radiation-force-depend-on-group-velocity-or-on-phase-velocity

The answer is phase velocity

Therefore any explanations for thrust (like Shawyer's for example) which are based on a difference between group velocities, are just plain wrong.

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

Inside a waveguide, the wave travels at group velocity and not at phase velocity which would be faster than c.

Shawyer is correct to model end plate forces based on end plate group velocity, which is related to guide wavelength as per the attached.

Any text on waveguides will tell you the energy in the waveguide propogates down the waveguide at group velocity speed.

What you said is correct, if you are looking at energy. However, mass is different. If you want to convert from energy to mass;

(dE/vgroup) = (dM*c2/vgroup) = (dM*vphase)

So momentum depends on phase velocity. It makes a huge difference!

Todd

Offline TheTraveller

http://physics.stackexchange.com/questions/190018/does-radiation-force-depend-on-group-velocity-or-on-phase-velocity

The answer is phase velocity

Therefore any explanations for thrust (like Shawyer's for example) which are based on a difference between group velocities, are just plain wrong.

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

Inside a waveguide, the wave travels at group velocity and not at phase velocity which would be faster than c.

Shawyer is correct to model end plate forces based on end plate group velocity, which is related to guide wavelength as per the attached.

Any text on waveguides will tell you the energy in the waveguide propagates down the waveguide at group velocity speed.

What you said is correct, if you are looking at energy. However, mass is different. If you want to convert from energy to mass;

(dE/vgroup) = (dM*c2/vgroup) = (dM*vphase)

So momentum depends on phase velocity. It makes a huge difference!

Todd

Phase velocity is way over 1c inside a waveguide. You still want to run with phase velocity?

Cullen equation 15 uses the ratio Lambda0 (free) / Lambdag (guide wavelength) as per attached. Simple to derive group velocity from guide wavelength being Vg = c * (Lambda0 / Lambdag)

I have never seen any reference that phase velocity is involved, in a waveguide, in determining the bounce Force imparted to an end plate. If you have a few references, please provide the links.

If you have a look at the equation Shawyer uses, as attached, it sure seems to be the same one Cullen is using to calculate Force generated on a end plate bounce.

You sure you want to say Cullen is wrong in how he calculated the Force generated on the end plate when his microwave EM wave bounced off it?

If Cullen is right then Shawyer is right as Shawyer uses Cullen's equation 15, which is based on the guide wavelength.
« Last Edit: 07/05/2015 06:13 AM by TheTraveller »
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Offline WarpTech

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DERIVATION OF THRUST FROM A TAPERED WAVEGUIDE PHOTON ROCKET

I updated the equations to make the derivation clearer.  In these equations, z is the axis of the cone, theta is the half-angle, E is energy, M and m are mass terms, and the rest is just wave vectors in a waveguide.

You can see that if the cone were not tapered there would be no dependence on z, the last term in the force equation would not exist. If it were not starting in a waveguide, the phase velocity would be c. Then we have a "flashlight" photon rocket. This is a different animal. This Force only applies when the big end is OPEN! Closed, all bets are off, but this explains where the tremendous thrust to power ratios are coming from.

FYI: This is the foundation of the paper I'm writing. Now you have the "tech" right in front of you while I try to put this in "writing". Have at it! Can't wait to see what sort of designs you come up with. 8)
Todd
« Last Edit: 07/05/2015 06:32 AM by WarpTech »

Offline demofsky

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.....
I'm not sure that everybody has appreciated the fact that the Poyinting vector field shown in this message: http://forum.nasaspaceflight.com/index.php?topic=37642.msg1399795#msg1399795 shows a very non-harmonic, asymmetric nonlinear time response cycle and its implications: 
.....

I completely agree with this.  While the pointing vector behaviour was a delightful discovery, the nonlinear behaviours are, for me, the real upside for the EM drive vs the standard photon drive.  These behaviours offer the possibility that Shawyer's and Yang's claims can be confirmed.
« Last Edit: 07/05/2015 07:37 AM by demofsky »

Offline demofsky

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This guys think another way

http://arxiv.org/abs/0708.3519

:)

This is a very interesting paper.  From the first paragraph of p 10:
Quote
The effective rest mass of guided photons inside a hollow waveguide, as the rest energy of photons inside the waveguide (i.e., the energy as the group velocity vg =0), arises by forming standing-waves along the transverse cross-section of the waveguide. In other words, it arises by freezing out the degree of freedom of transverse motion, or, by localizing and confining the electromagnetic energy along the 2D space perpendicular to the waveguide.

Hm.
« Last Edit: 07/05/2015 07:36 AM by demofsky »

Online guckyfan

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I got to admit that I did not wade through the last 1000 posts. Mostly because much of it is way over my head.

So forgive me that question. Is there a timeframe to expect results from the new test setup of NASA Eagleworks?

Offline ThinkerX

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Quote
So forgive me that question. Is there a timeframe to expect results from the new test setup of NASA Eagleworks?

This July or August...maybe.  At least that was when they were hoping to conduct the next round of tests, as of word here a few months ago. 

Also, this July, Tajmar (sp?) is supposed to give a presentation on his (?) recent EM Drive research.

Plus, we have two or three DIY posters here, employing the best info available, who should be conducting tests and releasing results end of July, more or less. 




Offline TheTraveller

Following discussions with Roger Shawyer, I now understand why using a scale to measure EMDrive Force generation is a waste of time.

1) Basically when you sit the EMDrive on your scale based measurement system, it will be non moving.

2) Once you fill the frustum with microwaves it will be in IDLE mode waiting for some external Force to move/vibrate it slightly big end to small end.

3) Once that happens the EMDrive enters MOTOR mode and starts to build up an external Force. That Force will push against the measurement system and achieve a slight amount of room to slightly accelerate.

4) However soon after what ever compressive movement that was there is now gone, the EMDrive stops moving and flips back into IDLE mode and shutting off Force generation.

The only way to allow the EMDrive to properly enter MOTOR mode and stay there needs the EMDrive to be free to move / accelerate.

My test rig is now being redesigned into a rotary, totally enclosed, low air resistance and battery powered system that will allow continual acceleration for many minutes. A high resolution optical encoder will measure angular rotation to approx 1 part in 10,000 per revolution. On board will be a 8 channel data recorder which will accurately measure battery energy usage.

The system will be able to resolve the apparent CofE paradox:

1) Device continually accelerates obeying A = F/M

2) KE increases at 1/2MV^2.

The measurement of power supply energy consumed by the 20W RF amp as against KE will be done and compared.

The tests will be streamed live. Data will be uploaded after the rotary test rigs stops spinning as there is not a laptop in the spinning test rig.

My gut says I will see a constant energy usage by the 20W RF amp, constant acceleration and KE going up faster than the energy used by the 20W RF amp.

I'm thinking about how to measure if the accumulated KE is real or just numbers on a piece of paper. Would need some form on a Pony Brake or something similar.

Any suggestions most welcome

Crude drawing of rotary test rig attached.
« Last Edit: 07/05/2015 10:33 AM by TheTraveller »
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Online guckyfan

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Thanks to ThinkerX.

Offline arc

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Degrasse Tyson sumed my work philosophy in Cosmos Unafraid of The Dark.
"Question authority.
No idea is true just because someone says so, including me.
Think for yourself.
Question yourself.
Don't believe anything just because you want to.
Believing something doesn't make it so.
Test ideas by the evidence gained from observation and experiment.
If a favorite idea fails a well-designed test, it's wrong! Get over it.
Follow the evidence, wherever it leads.
If you have no evidence, reserve judgment.
And perhaps the most important rule of all Remember, you could be wrong.
Even the best scientists have been wrong about some things.
Newton, Einstein, and every other great scientist in history, they all made mistakes.
Of course they did-- they were human."

Another one to add to the list.
He who makes No Mistakes... does No Work.

Offline Prunesquallor

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Following discussions with Roger Shawyer, I now understand why using a scale to measure EMDrive Force generation is a waste of time.

1) Basically when you sit the EMDrive on your scale based measurement system, it will be non moving.

2) Once you fill the frustum with microwaves it will be in IDLE mode waiting for some external Force to move/vibrate it slightly big end to small end.

3) Once that happens the EMDrive enters MOTOR mode and starts to build up an external Force. That Force will push against the measurement system and achieve a slight amount of room to slightly accelerate.

4) However soon after what ever compressive movement that was there is now gone, the EMDrive stops moving and flips back into IDLE mode and shutting off Force generation.

The only way to allow the EMDrive to properly enter MOTOR mode and stay there needs the EMDrive to be free to move / accelerate.

My test rig is now being redesigned into a rotary, totally enclosed, low air resistance and battery powered system that will allow continual acceleration for many minutes. A high resolution optical encoder will measure angular rotation to approx 1 part in 10,000 per revolution. On board will be a 8 channel data recorder which will accurately measure battery energy usage.

The system will be able to resolve the apparent CofE paradox:

1) Device continually accelerates obeying A = F/M

2) KE increases at 1/2MV^2.

The measurement of power supply energy consumed by the 20W RF amp as against KE will be done and compared.

The tests will be streamed live. Data will be uploaded after the rotary test rigs stops spinning as there is not a laptop in the spinning test rig.

My gut says I will see a constant energy usage by the 20W RF amp, constant acceleration and KE going up faster than the energy used by the 20W RF amp.

I'm thinking about how to measure if the accumulated KE is real or just numbers on a piece of paper. Would need some form on a Pony Brake or something similar.

Any suggestions most welcome

Crude drawing of rotary test rig attached.

So you predict that the rig will experience angular acceleration, that is, rpms will increase until either 1) you shut off the power, or 2) air resistance and bearing friction equal the thruster torque?
Retired, yet... not

Offline zaphod_vi

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Or you could attach a mechanical device to the drive to induce a known oscillation/vibration. That way you can then vary the frequency/strength of the vibration and see its effect on thrust (if any).

Offline SeeShells

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I'll be the first to admit there is something going on and it deserves further testing.  I have never advocated, and never will, that testing should be abandoned.  However, I have always been clear that I feel the likelihood that that something is propellantless thrust to be very low.  Finding the exact quirk that gives the appearance of propellantless thrust is a worthwhile scientific endeavor in it's own right though.

Quote
I believe there is enough empirical data in such widely varying test beds and that this is just enough out of the noise of chance that there is something going on and it deserves further testing.

This right here is probably where you and I, and everyone else who has a different take on the emdrive from 100% likelihood to 0% likelihood, differ.  When the emdrive first popped back into the news last august, I always heard the word replication being thrown around.  Nasa has replicated a propellantless drive!  It was replicated by the Chinese!  UK inventor has drive replicated by Nasa and Chinese Labs!  These were the kinds of headlines I saw.  However, when you actually read through the individual papers, something practically explodes out at you.  None of the experiments are actually replications of any of the others:

The chinese got higher thrust from lower Q than Shawyer - goes against Shaywer's theory

Nasa didn't get thrust from a frustum without a dielectric - goes against Chinese and Shawyer's experimental results, goes against Shawyers theory.

Shawyer has gotten different thrust directions from different set-ups (dielectric vs. none) - goes against theory, just outright strange

So far, every experiment has used a drastically different apparatus, with different variable inputs and gotten massively different results.  Thrust direction has not even remained constant.  So when you look at the experiments in that light, the empirical data becomes rather sketchy.  To date, as far as I know, no lab has truly replicated any other, and that's a problem.

Edit:  A problem that may be be solved by all the DIY yourself projects that are coming online this month.  I may have to retire this criticism in a few weeks if strong data comes out of some of the replication attempts.

You and I are not far off on our assessment of the dozen or so published tests. It is a mixed bag from home brew to high tech labs. Yes, I agree the labs were different, the testing was different, directions of thrust were different, sketchy data, all of that. Here is where we diverge. If you are looking at something not under your control as a problem you're looking at it in the wrong way.

Within that mess of data are gems. Clues as to not what is wrong and a problem, but what went right. They all had thrust, they all showed an anomaly called thrust and the sketchy empirical data is in itself the clue (one didn't but I think I know why). When I looked and read and watched videos I asked myself what is the most common thread. Thrust in a enclosed box. It's not a problem it's a diamond in the rough clue, it's what went right! The thrust, it's going to be different, of course, the test beds were different. The time for duplicated tests will come and we'll fine tune the effect and analyze the poo out of it and enhance the effect, but not now.

I hope I can make a diamond in the rough clue and you know if it flops and nothing happens, that's not a problem.

Shell
   

Offline JackFlash

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Quoting Wallofwolfstreet:

"However, when you actually read through the individual papers, something practically explodes out at you.  None of the experiments are actually replications of any of the others:

The chinese got higher thrust from lower Q than Shawyer - goes against Shaywer's theory

Nasa didn't get thrust from a frustum without a dielectric - goes against Chinese and Shawyer's experimental results, goes against Shawyers theory.

Shawyer has gotten different thrust directions from different set-ups (dielectric vs. none) - goes against theory, just outright strange

So far, every experiment has used a drastically different apparatus, with different variable inputs and gotten massively different results.  Thrust direction has not even remained constant.  So when you look at the experiments in that light, the empirical data becomes rather sketchy.  To date, as far as I know, no lab has truly replicated any other, and that's a problem.

Edit:  A problem that may be be solved by all the DIY yourself projects that are coming online this month.  I may have to retire this criticism in a few weeks if strong data comes out of some of the replication attempts."



When I was moderating at reddit, this is precisely the reason that I applied such emphasis on science, and felt it so important to point out the alleged 'modality' of Shawyer's devices, and how they potentially impact both experimental regime and quality of data.

At no time did I tell anyone they had to do anything; at no time did I promote Shawyer's work over any one else's. The only thing I ever promoted was science: following the data. Frankly, until someone gets back to the core of experimental proof conceptually, there *is no meaningful data* you're all just fiddling around with dangerous transmitters; not doing science.

That really sucks because until someone get back on the science train, this will never resolve into anything good or bad or even ugly.

I don't promote Shawyer. I am not a 'believer' or a 'denier'. I follow data; but I'm finding, due to this core issue, that there is very little happening beyond some mildly interesting and colorful electromagnetic simulation.

It doesn't take a PhD to recognize this issue. Any 9th grade earth sciences student with a C average could point this out.
 

Minor edits for clarity
« Last Edit: 07/05/2015 01:17 PM by JackFlash »

Online Rodal

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did a search and did not find this... hope it was not posted yet
Quote
AIAA Propulsion and Energy Forum and Exposition
Hilton Orlando, Orlando, Florida...
TUESDAY, JULY 28, 2015
NFF-04. Future Flight Propulsion Systems
...5:00 PM - 5:30 PM
Direct Thrust Measurements of an EMDrive and Evaluation of Possible Side-Effects
Martin Tajmar
I wonder if someone from this thread could attend the conference and if there is a following Q/A, even mention some of the experiments discussed here, ask questions, etc.

I am looking forward to this presentation.  Unfortunately, I won't be attending.  I have tried to find out, from several different second-hand sources what has been the nature of Martin Tajmar's experiments.  It is my personal understanding that his EM Drive experiments have shown  very low force/InputPower readings for an EM Drive in a partial vacuum: less than a few dozen or so times the force/InputPower of a perfectly collimated photon rocket, thus much lower thrust force/InputPower than Yang (who reported 300,000  times a photon rocket) and Shawyer (25,000 to 70,000 times) have reported.  I understand that the quality factor of resonance (Q) in the experiments is extremely low, much lower than any researcher has reported up to now. 

Regarding possible questions to ask if anybody attends, one suggestion (if this is what is reported) is to ask why is his experimental  Q so low (less than 100): how could the experiments have been conducted under resonance if the Q was so low?. Another question: what was responsible for such a low Q in the experiments, and whether Tajmar thinks that the discrepancy with other researchers has to do with the different Q reported from different researchers.

Another suggested question to Prof. Tajmar: given the very low force/InputPower readings for an EM Drive in a partial vacuum measured by Prof. Tajmar (less than a few dozen or so times the force/InputPower of a perfectly collimated photon rocket),  does Prof. Tajmar see his (and Georg Fiedler's) experiments at The Technische Universität Dresden as a scientific nullification of the claims made by Yang  and Shawyer, since Yang and Shawyer claim over 1,000 to 10,000 times greater force/InputPower than what Tajmar measured) ?

Does Prof. Tajmar think that the reason why Shawyer and Yang claimed much higher thrust is because Shawyer and Yang reported tests at ambient pressure (unlike Prof. Tajmar who has performed his tests in a vacuum), and Shawyer and Yang just reported thermal convection artifacts?

If, not a nullification due to Shawyer and Yang not performing tests in vacuum, what does Prof. Tajmar think that the huge difference (1,000 to 10,000 times) is due to ?
« Last Edit: 07/05/2015 02:52 PM by Rodal »

Offline ElizabethGreene

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Sorry, please explain to the Newtonian guy in me : how a play of throwing and bouncing and catching balls within a free floating box could give any persistent deltaV to the box ? deltaX I see, but not deltaV at the end of the story (when the game stops).

Quite simply, you can't by any known method.  You get nothing.  I've tried it experimentally, and simple radiation pressure is bound by conservation of momentum.  It doesn't work by simple bounces, period.

The emDrive does not appear to work this way.  You can't think of the light inside the cavity as individual photons, but instead consider the standing waves inside it.  The really exciting bits from the last meep run the subsequent S vector calculations.  As I see it, a portion of the standing waves "don't fit" the dimensions of the cavity and are being cut down to evanescent waves.  The same thing happens in an evanescent filter where you run a signal through a too-small piece of waveguide. These evanescent waves inside the cavity are concentrating at a point forward of their origin and combining to create a new S vector.  This is the unbalanced force that makes it go.

Prediction:
1. We'll figure out a way to make this effect occur without a resonator.
2. We'll prove Mach right, that there is a connection between inertia and gravity.
2a. Conservation of momentum will get a loophole.
2b. COM-violating actions that use this loophole will modify their inertia, creating a localized distortion in gravity.
2c. General relativity and the GUT will both need a new equation to describe it.

That will keep the Nobel prize committee busy for a decade

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