Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1797465 times)

Offline deltaMass

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If it works, then conservation of momentum does not hold, so Noether is wrong, so physics will have to be reformulated. Also, either thrust goes like F = k P, which implies that unlimited free energy is available from a perpetual motion machine of the first kind, or it goes like F = P/v, which implies that a preferred inertial reference frame exists, which violates a core principle of relativity and Einstein is wrong.

Feeling lucky?

Offline ThereIWas3

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There is technology that makes air currents visible.  I do not know the details, but I know that the Germans were doing this in wind tunnels during WW2 in their rocket program - I assume there have been improvements since.  (source, Walter Dornberger's book "V2")

I wonder if testing an EMdrive with such technology would reveal air moving around the cavity as a result of heating or electrostatic imbalances  or something that would explain the observed "thrust".  This would provide more information about what is actually happening than just "it doesn't work in vacuum".
"If you want to build a ship, don’t drum up people to collect wood and don’t assign them tasks and work, but rather teach them to long for the endless immensity of the sea" - Antoine de Saint-Exupéry

Offline SeeShells

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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
Well done. I've been following this same path but you just said it better and quite clear with the evanescent wave actions combining to another S vector. 

Shell

Offline 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 ?

For background reference research purposes, I attach Tajmar et.al.'s previous paper on the peer-reviewed (presently edited by the Program Director, Plasma Physics, US National Science Foundation) IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 43, NO. 1, JANUARY 2015 detailing the thrust balance with a resolution of 0.1 μN at Airbus Defence and Space developed with the Technische Universität Dresden for electric propulsion experiments.
« Last Edit: 07/05/2015 03:29 PM by Rodal »

Offline RonM

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If it works, then conservation of momentum does not hold, so Noether is wrong, so physics will have to be reformulated. Also, either thrust goes like F = k P, which implies that unlimited free energy is available from a perpetual motion machine of the first kind, or it goes like F = P/v, which implies that a preferred inertial reference frame exists, which violates a core principle of relativity and Einstein is wrong.

Feeling lucky?

True if CoM is violated, but why can't there be something else going on that preserves CoM? If changes in KE maintain a v2 relationship, then there is no problem.

When we get better experimental data we can see if there is anything to EM drives. Obviously, current theory isn't going to explain it (perhaps not easily) and it can't throw Noether or Enstein out the window.

Propellantless propulsion is possible with magnetic fields. Maybe something similar is going on with EM drives. Then again, it could all be experimental error. We need more data.

Offline Rodal

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« Last Edit: 07/05/2015 03:36 PM by Rodal »

Online Ricvil

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http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=1040027


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


Where the first equation comes from, and what is "Xmn" ???
« Last Edit: 07/05/2015 03:41 PM by Ricvil »

Offline wallofwolfstreet

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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.

Maybe I misunderstand you, but I'm going to keep saying it for good measure:  The Poynting vector, S, is NOT a force.  Just because you see a net, time-averaged Poynting vector doesn't mean you can conclude anything about any unbalanced forces.  An constant unbalanced force  could only be generated if you saw that Poynting vector continuously and endlessly growing. 

This is the link to my previous comment on this issue.   

Offline zen-in

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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.


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.

That agrees with some of my earlier observations on the NASA Eagleworks experiments.   We both agree that none of the Eagleworks experiments showed any force being generated.   You say it was impossible for a force to have been produced because they did not use the freely rotating apparatus Mr. Shawyer used and I say no force was produced because the response when RF was switched on did not match the response from the calibration force.   I think the Chinese university experiment falls into this same category.   No one has replicated Mr. Shawyer's experiment.

Offline deltaMass

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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.

Maybe I misunderstand you, but I'm going to keep saying it for good measure:  The Poynting vector, S, is NOT a force.  Just because you see a net, time-averaged Poynting vector doesn't mean you can conclude anything about any unbalanced forces.  An constant unbalanced force  could only be generated if you saw that Poynting vector continuously and endlessly growing. 

This is the link to my previous comment on this issue.   
Correct, as a cursory glance at the units of the Poynting vector will show. It has units of power per unit area, whereby the area refers to the plane orthogonal to the direction of the power flux
« Last Edit: 07/05/2015 04:04 PM by deltaMass »

Offline deltaMass

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New Baby EM Drive "results"

https://hackaday.io/project/5596-em-drive/log/20473-preliminary-tests-swimming-platform
You may well use quotation marks, because the SNR is so poor that no definitive conclusions can be drawn, save possibly that the data is consistent with the null hypothesis.

Offline Rodal

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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.

Maybe I misunderstand you, but I'm going to keep saying it for good measure:  The Poynting vector, S, is NOT a force.  Just because you see a net, time-averaged Poynting vector doesn't mean you can conclude anything about any unbalanced forces.  An constant unbalanced force  could only be generated if you saw that Poynting vector continuously and endlessly growing. 

This is the link to my previous comment on this issue.   
Correct, as a cursory glance at the units of the Poynting vector will show. It has units of power per unit area, whereby the area refers to the plane orthogonal to the direction of the power flux

..
Maybe I misunderstand you, but I'm going to keep saying it for good measure:  The Poynting vector, S, is NOT a force.  Just because you see a net, time-averaged Poynting vector doesn't mean you can conclude anything about any unbalanced forces.  An constant unbalanced force  could only be generated if you saw that Poynting vector continuously and endlessly growing. 
...

Incorrect, another over-statement, http://forum.nasaspaceflight.com/index.php?topic=37642.msg1399888#msg1399888 as it is elementary knowledge that  the time-averaged (over an integer number of periods) of the Poynting vector divided by the speed of light in free space is the radiation pressure exerted by an electromagnetic wave on the surface of a target, if the wave is completely absorbed by the target .

Stress = <Poynting vector averaged over integer number of periods> / c 

this formula has been verified experimentally multiple times since 1900 when the wave is absorbed by the target

Poynting vector = Power Surface Density = Power/area = Force*Velocity/area

Stress= Force/Area = (Power/area)/CharacteristicVelocity =(Powery/area)/SpeedOfLight

As photons travel at the speed of light

Quote from: Anson Mount
I'm an enemy of exposition. I feel there's no need to overstate.
 

« Last Edit: 07/05/2015 04:45 PM by Rodal »

Offline deltaMass

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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.

Maybe I misunderstand you, but I'm going to keep saying it for good measure:  The Poynting vector, S, is NOT a force.  Just because you see a net, time-averaged Poynting vector doesn't mean you can conclude anything about any unbalanced forces.  An constant unbalanced force  could only be generated if you saw that Poynting vector continuously and endlessly growing. 

This is the link to my previous comment on this issue.   
Correct, as a cursory glance at the units of the Poynting vector will show. It has units of power per unit area, whereby the area refers to the plane orthogonal to the direction of the power flux

Incorrect, another over-statement, http://forum.nasaspaceflight.com/index.php?topic=37642.msg1399888#msg1399888 as it is elementary knowledge that  the time-averaged (over an integer number of periods) of the Poynting vector divided by the speed of light in free space is the radiation pressure exerted by an electromagnetic wave on the surface of a target, if the wave is completely absorbed by the target .

Stress = <Poynting vector averaged over integer number of periods> / c

this formula has been verified experimentally multiple times since 1900 when the wave is absorbed by the target

Poynting vector = Power Surface Density = Power/area = Force*Velocity/area

Stress= Force/Area = (Power/area)/CharacteristicVelocity =(Powery/area)/SpeedOfLight

As photons travel at the speed of light
Incorrect if you are disputing the units of the Poynting vector as I described them. Are you?

Offline wallofwolfstreet

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New Baby EM Drive "results"

https://hackaday.io/project/5596-em-drive/log/20473-preliminary-tests-swimming-platform

Brutal honesty time, and I hope any of the Hackaday guys reading this take it as constructive criticism.

Holy hell, that data is a hot mess. 

First things first, label graphs.  An unlabelled graph is like a map without any street names; kinda defeats the purpose.

Secondly, it should be a crime against humanity to take data that noisy and presents it's average without any indication of deviation, either using an error bar across the whole average line (so you end up with an average rectangle so to speak) or making a note on the side.  I was being serious when I said crime against humanity.  Just by looking at the data, I can almost guarantee you that if you applied a t-test to your calculated means, you would get that there is no statistical significance.   

Third, what, if anything, can explain the massive differences that occur between two separate instances of ON vs OFF for a single direction of rotation?  It looks like when rotating CCW, the difference between one ON vs OFF cycle was maybe 1/5 of the other ON vs. OFF cycle.

Also, there is clearly one source of systematic error in that the setup; it is affected dramatically be electrical power loads being turned on and off.  For example the sudden jump of about 20 units may be due to a neighbour toggling a power load?  If a neighbor's household appliance affected the setup that much, than the power supply to the emdrive or even your data logging laptop would have done the same.  Since the difference between ON and OFF seems to be in the 0.5-3 range, we know that measured signal values are clearly well below this systematic error.
« Last Edit: 07/05/2015 04:18 PM by wallofwolfstreet »

Offline Rodal

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....Incorrect if you are disputing the units of the Poynting vector as I described them. Are you?
For non-elementary problems in Physics  the fundamental quantity to derive forces is the stress.   The equations of equilibrium for non-uniform stress are formulated in terms of stress and not forces. 

Offline Prunesquallor

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New Baby EM Drive "results"

https://hackaday.io/project/5596-em-drive/log/20473-preliminary-tests-swimming-platform

I'm having trouble interpreting that data. Does "cavity off" mean he is powering the electronics, but not feeding power to the thruster?
Retired, yet... not

Offline deltaMass

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....Incorrect if you are disputing the units of the Poynting vector as I described them. Are you?
For non-elementary problems in Physics  the fundamental quantity to derive forces is the stress.   The equations of equilibrium for non-uniform stress are formulated in terms of stress and not forces.
I don't care. I described the units of the Poynting vector and you replied with "incorrect". You either need to say why I'm incorrect or retract your statement.

Offline ElizabethGreene

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Maybe I misunderstand you, but I'm going to keep saying it for good measure:  The Poynting vector, S, is NOT a force
Apologies if I've used the wrong word here then. Please offer a better name for it then.  I am specifically referring to the force that follows the vector of the cross product of perpendicular evanescent E and B fields.  It's the force used to move particles with Total Internal Reflection Microscopy, and my $0.37 says its the force moving the emdrive.

Offline WarpTech

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http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=1040027


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


Where the first equation comes from, and what is "Xmn" ???

It comes from the circular resonator equation. Where, Xmn  denotes the n-th zero of the m-th cylindrical Bessel function, used for TM modes. For TE modes, X'mn  denotes the n-th  zero of the derivative of the m-th cylindrical Bessel function. Rather than a longitudinal p-mode, I've shown it as kz as a traveling wave.
Todd

Offline SeeShells

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Again...!

http://www.nature.com/ncomms/2014/140306/ncomms4300/full/ncomms4300.html
Momentum and spin represent fundamental dynamic properties of quantum particles and fields. In particular, propagating optical waves (photons) carry momentum and longitudinal spin determined by the wave vector and circular polarization, respectively. Here we show that exactly the opposite can be the case for evanescent optical waves. A single evanescent wave possesses a spin component, which is independent of the polarization and is orthogonal to the wave vector. Furthermore, such a wave carries a momentum component, which is determined by the circular polarization and is also orthogonal to the wave vector. We show that these extraordinary properties reveal a fundamental Belinfante’s spin momentum, known in field theory and unobservable in propagating fields. We demonstrate that the transverse momentum and spin push and twist a probe Mie particle in an evanescent field. This allows the observation of ‘impossible’ properties of light and of a fundamental field-theory quantity, which was previously considered as ‘virtual’.
End Quote

Here we go, beat me up as I'm shooting from the hip, We have been looking in the standard model to explain force and thrust of the EMDrive, it's not there, Elizabeth is right on the money, we need to invoke the links into the quantum world for it is there where we will find the fundamental first order forces and the dynamic properties of quantum particles and associated fields the explain the thrust.

This combines the poynting vectors which are time averaged in the area of the antenna in Dr. Rodals and Aero's data from a deep meep analysis. The time averaged pointing vectors are summed in a asymetrical level to be pointing towards the larger end of the fulcrum. This in itself is contributing to the strength of the evanescent field that is forming 1/3 wavelength from the antenna. (quote) A single evanescent wave possesses a spin component, which is independent of the polarization and is orthogonal to the wave vector. Furthermore, such a wave carries a momentum component, which is determined by the circular polarization and is also orthogonal to the wave vector. (end quote)

When I asked Todd about the evanescent waves he said it correctly, he said to the effect "The evanescent waves are all over the cavity". (hate the search function)

If were looking for a first order function of momentum spin and and force coupling into the quantum mechanics of the drive I believe it's right here.

Shell

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