Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1797021 times)

Offline Notsosureofit

  • Full Member
  • ****
  • Posts: 656
  • Liked: 704
  • Likes Given: 1361
Perpetual motion is a "circular" argument. (pun intended)

Offline Paul Novy

  • Member
  • Posts: 12
  • Poland
  • Liked: 11
  • Likes Given: 3
This reminds me of my physics professor at the university. He thought that the thermodynamics does not exist and we will omit that part of the course  :P

Offline Star One

  • Senior Member
  • *****
  • Posts: 7975
  • UK
  • Liked: 1276
  • Likes Given: 168

June 2, 2015 new buzzkill paper: http://arxiv.org/pdf/1506.00494.pdf FYI only

"IV. CONCLUSIONS

The fact that the EM drive, or any other reactionless drive that has a thrust-to-power
ratio greater than a photon-emitting device, would enable a perpetual motion machine of the
first kind suggests that such a device cannot exist. This objection is not as easily explained
away as the conservation of momentum objection to a reactionless drive, because this result
suggests than a source of free and infinite energy is already at our technological disposal.
Any conditions placed on the operation of the hypothetical “space drive” in order to make
is consistent with the First Law would also render it useless as a propulsion device; if it can
work as a propulsion device, it can also function as a perpetual motion machine of the first
kind. Further investment into investigating this concept should be tempered by the history
of attempts to realize perpetual motion machines."

One does wonder if much of the buzzkill is a thinly disguised funding suggestion ;)

It looks like a repetition of all the arguments already published by @frobnicat's in his discussions in these NSF EM Drive threads, but fails to give any credit to @frobnicat.

Unless frobnicat is Higgins which is unlikely ;). Good catch Doc.

Be interesting to see what the former has to say about this matter.

Online Rodal

  • Senior Member
  • *****
  • Posts: 5833
  • USA
  • Liked: 5900
  • Likes Given: 5248
...

Instead of the stored energy (5000J) being released out the back, it is attenuated and absorbed at the front. The result is the same, the frustum absorbs 5000J of energy as work done on it's mass, preferably all on one side.

Todd


"Physical Audio Signal Processing'', by Julius O. Smith III, W3K Publishing, 2010, ISBN 978-0-9745607-2-4.
Copyright © 2015-05-22 by Julius O. Smith III (*)

Stanford University

https://ccrma.stanford.edu/~jos/pasp/Wave_Impedance_Cone.html

Bibliography:  https://ccrma.stanford.edu/~jos/pasp/Bibliography.html#LevineAndSchwingerBothParts48

===>(Acoustic)<===

Wave Impedance in a Cone

The real part of the wave impedance corresponds to transportation of wave energy, the imaginary part is a so-called ``reactance'' and does not correspond to power transfer. Instead, it corresponds to a ``standing wave'' which is created by equal and opposite power flow, or an ``evanescent wave'' (§C.8.2), which is a non-propagating, exponentially decaying, limiting form of a traveling wave in which the ``propagation constant'' is purely imaginary due to being at a frequency above or below a ``cut off'' frequency for the waveguide[297,122].

Driving an ideal mass at the end of a waveguide results in total reflection of all incident wave energy along with a quarter-cycle phase shift. Another interpretation is that the traveling wave becomes a standing wave at the tip of the cone. This is one way to see how the resonances of a cone can be the same as those of a cylinder the same length which is open on both ends. (One might first expect the cone to behave like a cylinder which is open on one end and closed on the other.) Because the impedance approaches a purely imaginary zero at the tip, it looks like a mass. The ``piston of air'' at the open end similarly looks like a mass




===>(Acoustic)<===

Momentum Conservation in Nonuniform Tubes

Physical Audio Signal Processing'', by Julius O. Smith III, W3K Publishing, 2010, ISBN 978-0-9745607-2-4.
Copyright © 2015-05-22 by Julius O. Smith III

Newton's second law ``force equals mass times acceleration'' implies that the pressure gradient in a gas is proportional to the acceleration of a differential volume element in the gas.

Quote from: Notsosureofit
The proposition that dispersion caused by an accelerating frame of reference implied an accelerating frame of reference caused by a dispersive cavity resonator. (to 1st order using massless, perfectly conducting cavity)

https://ccrma.stanford.edu/~jos/pasp/Momentum_Conservation_Nonuniform_Tubes.html



(*) This book describes signal-processing models and methods that are used in constructing virtual musical instruments and audio effects. Specific topics considered include delay effects such as phasing, flanging, the Leslie effect, and artificial reverberation; virtual acoustic musical instruments such as guitars, pianos, bowed strings, woodwinds, and brasses; and various component technologies such as digital waveguide modeling, wave digital modeling, commuted synthesis, resonator factoring, feedback delay networks, digital interpolation, Doppler simulation, nonlinear elements, finite difference schemes, passive signal processing, and associated software
« Last Edit: 06/03/2015 03:04 PM by Rodal »

Offline aero

  • Senior Member
  • *****
  • Posts: 2736
  • 92129
  • Liked: 704
  • Likes Given: 235
the near field propagates faster than light?  I'm not sure I can bring myself to swallow that just yet.


Superluminal Group Velocity of Electromagnetic Near-field
http://arxiv.org/abs/physics/0311061

 :)

There are dozens of papers reporting experiments measuring superluminal propigation of evanescent EM waves. Use Google to find your favorites.

It happens that the solution of the wave equations (Maxwell) are very similar, if not identical to the equations discribing the tunneling phenomona. I wonder if tunneling and superluminal propagation may be in fact the same phenomona? Does anyone know of any experimental measurements of momentum resulting from electron tunneling?
« Last Edit: 06/03/2015 02:45 PM by aero »
Retired, working interesting problems

Online Rodal

  • Senior Member
  • *****
  • Posts: 5833
  • USA
  • Liked: 5900
  • Likes Given: 5248
the near field propagates faster than light?  I'm not sure I can bring myself to swallow that just yet.


Superluminal Group Velocity of Electromagnetic Near-field
http://arxiv.org/abs/physics/0311061

 :)

There are dozens of papers reporting experiments measuring superluminal propigation of evanescent EM waves. Use Google to find your favorites.

It happens that the solution of the wave equations (Maxwell) are very similar, if not identical to the equations discribing the tunneling phenomona. I wonder if tunneling and superluminal propagation may be in fact the same phenomona? Does anyone know of any experimental measurements of momentum resulting from electron tunneling?
I agree.

SUBJECTIVE OPINION: I much prefer the wording " tunneling phenomena" to "superluminal propagation" as it does not necessarily involve the need to invoke the existence of tachyons. 

QUESTION 1: The group velocity is superluminal.  Is the phase velocity subluminal ?

The number of photons in a photon gas is not a thermodynamic constant but it is proportional to the cube of the temperature of the photon gas. In the Photonic Laser Thruster, collimated photons are reused by mirrors, multiplying the force by the number of bounces. QUESTION 2:   Under Q resonance can the number of photons able to achieve "tunneling phenomena", be greater than the number of photons emitted by a traditional photon rocket?

« Last Edit: 06/03/2015 03:50 PM by Rodal »

Offline MyronQG

  • Member
  • Posts: 14
  • Liked: 9
  • Likes Given: 5

June 2, 2015 new buzzkill paper: http://arxiv.org/pdf/1506.00494.pdf FYI only

"IV. CONCLUSIONS

The fact that the EM drive, or any other reactionless drive that has a thrust-to-power
ratio greater than a photon-emitting device, would enable a perpetual motion machine of the
first kind suggests that such a device cannot exist. This objection is not as easily explained
away as the conservation of momentum objection to a reactionless drive, because this result
suggests than a source of free and infinite energy is already at our technological disposal.
Any conditions placed on the operation of the hypothetical “space drive” in order to make
is consistent with the First Law would also render it useless as a propulsion device; if it can
work as a propulsion device, it can also function as a perpetual motion machine of the first
kind. Further investment into investigating this concept should be tempered by the history
of attempts to realize perpetual motion machines."

One does wonder if much of the buzzkill is a thinly disguised funding suggestion ;)

It looks like a repetition of all the arguments already published by @frobnicat's in his discussions in these NSF EM Drive threads, but fails to give any credit to @frobnicat.

Unless frobnicat is Higgins which is unlikely ;). Good catch Doc.

Be interesting to see what the former has to say about this matter.
If it can help, here you find and old and "classical" demonstration of the impossibility of accelerating a closed system by converting the system internal energy into kinetic energy. Let's assimilate the spacecraft (including thruster, PPU, a.s.o.) to a particle having a rest mass m0 and 4-velocity V=(c/alpha, v/alpha) in an arbitrary Lorentzian frame. The 4-momentum of the particle, by definition is P=(mc, mv) with m=mo/alpha; if the particle is isolated (no interaction nor mass/energy exchange with the surrounding medium), then the relativistic conservation of momentum implies dP=(dm c, dm v)=0, i.e., dm=0 and d(m v)=0, so dv=0. Total energy is conserved and 3-momentum is also conserved, the former implying that according to the latter the system cannot accelerate.

Offline PaulF

  • Member
  • Posts: 52
  • Netherlands
  • Liked: 19
  • Likes Given: 9
Quote
Nothing is moving "backwards". Momentum is flowing INTO the boundary, NOT OUT of the boundary. It works both ways. Divergence is not zero when the source is turned on. The Poynting vector is not zero. The momentum put inside is then attenuated asymmetrically, and the resulting forces and amplitudes depend on the relative phase of the waves, not simply their time-averaged pressure. The conservation law says is that there must be divergence through the boundary, it can be in either direction, in or out. It isn't ONLY expelling something out that satisfies this condition.

Todd
I can think of something that is moving backwards. Our whole universe, including you, me, the test stand, and whatever is beneath or above it dimensionally :)
« Last Edit: 06/03/2015 03:13 PM by PaulF »

Offline WarpTech

  • Full Member
  • ****
  • Posts: 1223
  • Do it!
  • Vista, CA
  • Liked: 1290
  • Likes Given: 1737

I had similar ideas nearly 20 years ago! The conclusion I came to back then was that there is always the "hidden momentum" creating an equal and opposite force. If you use a 1/4-wave coupling of the electric field and the charge, you will have an opposite force between the magnetic field and the current, and in the end you have a photon rocket resulting from the leakage inductance and capacitance.
...


In regards to the underlined statement.  I know what you mean because static charge builds up and the force is counter to the magnetic.  Concerning a cylindrical cavity in TE01 mode, does the charge build up so as to provide that counter force?  It doesn't appear to me that there is a static charge build up in that mode. 
...


Yeah, we're on the same page alright. I can't answer this right now, I'm working on the same puzzle but with the TM01 mode, because with an axial conductor down the middle, it's easier to calculate. For any mode, you need to solve the equation;

force density = dD/dt X B + D X dB/dt

Surface charge is one way to look at it, another is the magnetic moment. In free space, the "difference" between these 2 cross products is typically a photon rocket. Inside a cavity however, it becomes an "attenuation rocket". I'm not sure of the outcome yet, so I'm working on it....

 

Offline WarpTech

  • Full Member
  • ****
  • Posts: 1223
  • Do it!
  • Vista, CA
  • Liked: 1290
  • Likes Given: 1737
...
If it can help, here you find and old and "classical" demonstration of the impossibility of accelerating a closed system by converting the system internal energy into kinetic energy. Let's assimilate the spacecraft (including thruster, PPU, a.s.o.) to a particle having a rest mass m0 and 4-velocity V=(c/alpha, v/alpha) in an arbitrary Lorentzian frame. The 4-momentum of the particle, by definition is P=(mc, mv) with m=mo/alpha; if the particle is isolated (no interaction nor mass/energy exchange with the surrounding medium), then the relativistic conservation of momentum implies dP=(dm c, dm v)=0, i.e., dm=0 and d(m v)=0, so dv=0. Total energy is conserved and 3-momentum is also conserved, the former implying that according to the latter the system cannot accelerate.

If you have a "Lorentzian frame", this is correct. However, in the frustum this is not true because you have a variable refractive index. It is no longer "Lorentzian" because there is an attenuation (acceleration) over a narrow bandwidth of the EM spectrum.

Todd



Offline X_RaY

  • Full Member
  • ****
  • Posts: 774
  • Germany
  • Liked: 993
  • Likes Given: 2141
Macroscopic and direct light propulsion of bulk graphene material

http://arxiv.org/abs/1505.04254

May be interesting...

Offline MyronQG

  • Member
  • Posts: 14
  • Liked: 9
  • Likes Given: 5
...
If it can help, here you find and old and "classical" demonstration of the impossibility of accelerating a closed system by converting the system internal energy into kinetic energy. Let's assimilate the spacecraft (including thruster, PPU, a.s.o.) to a particle having a rest mass m0 and 4-velocity V=(c/alpha, v/alpha) in an arbitrary Lorentzian frame. The 4-momentum of the particle, by definition is P=(mc, mv) with m=mo/alpha; if the particle is isolated (no interaction nor mass/energy exchange with the surrounding medium), then the relativistic conservation of momentum implies dP=(dm c, dm v)=0, i.e., dm=0 and d(m v)=0, so dv=0. Total energy is conserved and 3-momentum is also conserved, the former implying that according to the latter the system cannot accelerate.

If you have a "Lorentzian frame", this is correct. However, in the frustum this is not true because you have a variable refractive index. It is no longer "Lorentzian" because there is an attenuation (acceleration) over a narrow bandwidth of the EM spectrum.

Todd

Just take a marker and draw a spot on the spacecraft hull. The theory works equally well for the motion of that spot, irrespective of what's happening inside, provided nothing is coming out of the enclosing control volume. I hate to say that this is basic theory of propulsion (Koëlle, Handbook of Astronautical Engineering, 1962).

Offline WarpTech

  • Full Member
  • ****
  • Posts: 1223
  • Do it!
  • Vista, CA
  • Liked: 1290
  • Likes Given: 1737
...
If it can help, here you find and old and "classical" demonstration of the impossibility of accelerating a closed system by converting the system internal energy into kinetic energy. Let's assimilate the spacecraft (including thruster, PPU, a.s.o.) to a particle having a rest mass m0 and 4-velocity V=(c/alpha, v/alpha) in an arbitrary Lorentzian frame. The 4-momentum of the particle, by definition is P=(mc, mv) with m=mo/alpha; if the particle is isolated (no interaction nor mass/energy exchange with the surrounding medium), then the relativistic conservation of momentum implies dP=(dm c, dm v)=0, i.e., dm=0 and d(m v)=0, so dv=0. Total energy is conserved and 3-momentum is also conserved, the former implying that according to the latter the system cannot accelerate.

If you have a "Lorentzian frame", this is correct. However, in the frustum this is not true because you have a variable refractive index. It is no longer "Lorentzian" because there is an attenuation (acceleration) over a narrow bandwidth of the EM spectrum.

Todd

Just take a marker and draw a spot on the spacecraft hull. The theory works equally well for the motion of that spot, irrespective of what's happening inside, provided nothing is coming out of the enclosing control volume. I hate to say that this is basic theory of propulsion (Koëlle, Handbook of Astronautical Engineering, 1962).

A mass in a gravitational field "falls" yet nothing is coming out of the enclosing control volume either. It falls precisely because the stress energy Tensor in that volume is skewed to one side. This is what is happening inside the frustum, but only over a narrow bandwidth of the EM spectrum.

Offline aero

  • Senior Member
  • *****
  • Posts: 2736
  • 92129
  • Liked: 704
  • Likes Given: 235
the near field propagates faster than light?  I'm not sure I can bring myself to swallow that just yet.


Superluminal Group Velocity of Electromagnetic Near-field
http://arxiv.org/abs/physics/0311061

 :)

There are dozens of papers reporting experiments measuring superluminal propigation of evanescent EM waves. Use Google to find your favorites.

It happens that the solution of the wave equations (Maxwell) are very similar, if not identical to the equations discribing the tunneling phenomona. I wonder if tunneling and superluminal propagation may be in fact the same phenomona? Does anyone know of any experimental measurements of momentum resulting from electron tunneling?
I agree.

SUBJECTIVE OPINION: I much prefer the wording " tunneling phenomena" to "superluminal propagation" as it does not necessarily involve the need to invoke the existence of tachyons. 

QUESTION 1: The group velocity is superluminal.  Is the phase velocity subluminal ?

The number of photons in a photon gas is not a thermodynamic constant but it is proportional to the cube of the temperature of the photon gas. In the Photonic Laser Thruster, collimated photons are reused by mirrors, multiplying the force by the number of bounces. QUESTION 2:   Under Q resonance can the number of photons able to achieve "tunneling phenomena", be greater than the number of photons emitted by a traditional photon rocket?

Trying to find answer to your question, I find that we are not alone in preferring "tunneling phonomena" terminology.
I have posted this reference several times already, but http://wwwsis.lnf.infn.it/pub/INFN-FM-00-04.pdf
Quote
With regard to the same experiments, Guenter Nimitz claimed very recently [10] that those results with evanescent waves, or "tunnelling photons", do really imply Superluminal signal and impulse transmission.
pdf, can't copy/paste so quote is re-typed. Any errors in the quotation are mine.

Page 3, section 2

You will note that on page 15 of this paper, the evanescent wave equation is the same as the tunneling equation.
As for phase velocity and photon count, afraid I've struck out, so far.
Retired, working interesting problems

Offline frobnicat

  • Full Member
  • ****
  • Posts: 518
  • Liked: 500
  • Likes Given: 151
June 2, 2015 new buzzkill paper: http://arxiv.org/pdf/1506.00494.pdf FYI only

"IV. CONCLUSIONS

The fact that the EM drive, or any other reactionless drive that has a thrust-to-power
ratio greater than a photon-emitting device, would enable a perpetual motion machine of the
first kind suggests that such a device cannot exist. This objection is not as easily explained
away as the conservation of momentum objection to a reactionless drive, because this result
suggests than a source of free and infinite energy is already at our technological disposal.
Any conditions placed on the operation of the hypothetical “space drive” in order to make
is consistent with the First Law would also render it useless as a propulsion device; if it can
work as a propulsion device, it can also function as a perpetual motion machine of the first
kind. Further investment into investigating this concept should be tempered by the history
of attempts to realize perpetual motion machines."

One does wonder if much of the buzzkill is a thinly disguised funding suggestion ;)

It looks like an egregious repetition of the arguments previously published by @frobnicat's in discussions in these NSF EM Drive threads, but failing to give any credit to @frobnicat.

It is due @frobnicat's coherent and well formulated arguments that we decided to compare all EM Drive experimental force reports to the one of a perfectly collimated photon rocket, ever since we started to compile experimental records.


EDIT: The author of the above-mentioned article:   http://arxiv.org/pdf/1506.00494.pdf  is no @frobnicat



No I'm not the author of this paper, as dr Rodal who knows my "secret" identity can confirm. BTW it is secret not because of connection of my job with aerospace but complete lack thereof.

Anyway, I don't claim originality on this line of reasoning since it appears rather straightforward to me, and I think to a lot of people who haven't cared to write on that : silent dismissal of fringe science. Actually, I saw it made independently at other places, at least on talk polywell, by "believers" of propellantless ME scheme that dare go to the bold but consistent conclusions, and also by various sceptics on forums around. Neither more than me the author of this paper could really claim originality as I'm sure the objection is as old as the first claims of thrust/power>1/c... he is just putting it black on white, which has the merit of serving as a later reference. Though may be, as a reference, it would have benefited from a longer bibliography... and yes I would have appreciated a small citation (provided the author was aware of my communication efforts here).

My only original contribution on this line of refutation might be to illustrate how to put the break even velocity Vbe at 1/(thrust/power) rather than 2/(thrust/power) for Newtonian mechanics, i.e. low speeds, for instance with thrust/power=1N/kW yielding a Vbe of 1km/s instead of 2km/s, the CoE apparent breaking appears at more modest velocities when considering constant thrust/constant velocity rather than acquired velocity relative to starting frame. Even that I remember having seen elsewhere. This should appear in the paper, but maybe the author don't care about polishing the argument thus far, as from "this is breaking CoE" standpoint, Vbe=2/(thrust/power) is good enough.

Anyway, apart from Mach effect (Woodward) and QV plasma (White) contenders, both approaches being somehow compatible with tapping in a practically limitless energy source, and making possible a device such as the one depicted above (which is more or less publicly acknowledged by some followers), I saw none convincing argument that it could be possible to render compatible
1/ a working propellantless drive with averaged thrust/power>>1/c (useful for deep space flight)
2/ that don't act as a limitless energy source (for all practical purpose)
That is, for those wanting 1/ and 2/ : what would make the above depicted device fail (or equivalently, what would be the flaw in the cited paper) ? Obviously, just claiming that it does 1/ and still respects 2/ is not convincing by itself when those aspect are treated inconsistently.

It is to be expected as propellantless propulsion phenomenological claims gain in attention that more and more sceptics find the motivation to publish refutations that otherwise would have been kept in the realm of polite pass over. Unfortunately there is still not enough incentive right now for big labs to hunt for experimental null results. What is the point to confirm the inexistence of something that the overwhelming majority of establishment is knee jerkedly considering bogus ? When (if) apparent positives pile up, then this incentive will rise and maybe we will start to see more null results published. I'm convinced there are already a lot of null results out there, just not published/advertised.

ps. Thanks rfmwguy & dr Rodal, et al.  :D

Online Rodal

  • Senior Member
  • *****
  • Posts: 5833
  • USA
  • Liked: 5900
  • Likes Given: 5248
Please notice that the first worldwide replication test by a "Do it yourself", by Iulian Berca (in Romania), had a measured thrust force that when calculated as an average of runs in tests 3 and 3.1, subtracting out the likely "gas effect", as per @deltaMass calculated net thrust of 0.29gf effective thrust, which is 2.84mN, according to the EM Drive wiki page:  http://emdrive.wiki/Experimental_Results

Also notice that Iulian Berca used the same geometrical dimensions as NASA's truncated cone

Also notice that a truncated cone with the same geometrical dimensions as NASA's truncated cone and without a dielectric, will experience resonance at the magnetron frequency ~ 2.45 GHz in mode shape TM212. Exactly the same mode shape that NASA Eagleworks has used for all the tests in Brady's a, Brady's b tests in ambient air and March's test in vacuum.

Now, notice that the thrust per InputPower measured by Iulian Berca, with a completely different experimental setup than NASA's, and with a completely different power (800 watts instead of 17 watts used at NASA) is

Researcher      Mode shape      Power (watts)    Force / PowerInput (mN/kW)  for
Iulian Berca     TM212             800                   3.55
NASA Brady a  TM212               17                   5.396
NASA Brady b  TM212               17                   3.00

Tha's really good agreement for Force/PowerInput, considering all the variables involved.


Notice that the Force/Power Input measured by NASA and by Iulian Berca are 6 to 27-80 times less than those reported by Shawyer for the Experimental and Demo respectively.

Notice that both NASA and Iulian Berca measured 1000 times greater thrust/PowerInput than a perfectly collimated photon rocket

The early test reported by Paul March in vacuum, giving 55 microNewtons at 50 watts gives Force / PowerInput (mN/kW) of only 1.1.  If this was the result of Paul not quite tuning his system during that early test, indications are (using a multiplier factor of 3 to 5 times based on the above data) that he should be able to get 150 to 250  microNewtons with 50 watts when optimizing his test (if vacuum is not responsible for the smaller results)
« Last Edit: 06/03/2015 07:53 PM by Rodal »

Offline Star One

  • Senior Member
  • *****
  • Posts: 7975
  • UK
  • Liked: 1276
  • Likes Given: 168

June 2, 2015 new buzzkill paper: http://arxiv.org/pdf/1506.00494.pdf FYI only

"IV. CONCLUSIONS

The fact that the EM drive, or any other reactionless drive that has a thrust-to-power
ratio greater than a photon-emitting device, would enable a perpetual motion machine of the
first kind suggests that such a device cannot exist. This objection is not as easily explained
away as the conservation of momentum objection to a reactionless drive, because this result
suggests than a source of free and infinite energy is already at our technological disposal.
Any conditions placed on the operation of the hypothetical “space drive” in order to make
is consistent with the First Law would also render it useless as a propulsion device; if it can
work as a propulsion device, it can also function as a perpetual motion machine of the first
kind. Further investment into investigating this concept should be tempered by the history
of attempts to realize perpetual motion machines."

One does wonder if much of the buzzkill is a thinly disguised funding suggestion ;)

It looks like an egregious repetition of the arguments previously published by @frobnicat's in discussions in these NSF EM Drive threads, but failing to give any credit to @frobnicat.

It is due @frobnicat's coherent and well formulated arguments that we decided to compare all EM Drive experimental force reports to the one of a perfectly collimated photon rocket, ever since we started to compile experimental records.


EDIT: The author of the above-mentioned article:   http://arxiv.org/pdf/1506.00494.pdf  is no @frobnicat



No I'm not the author of this paper, as dr Rodal who knows my "secret" identity can confirm. BTW it is secret not because of connection of my job with aerospace but complete lack thereof.

Anyway, I don't claim originality on this line of reasoning since it appears rather straightforward to me, and I think to a lot of people who haven't cared to write on that : silent dismissal of fringe science. Actually, I saw it made independently at other places, at least on talk polywell, by "believers" of propellantless ME scheme that dare go to the bold but consistent conclusions, and also by various sceptics on forums around. Neither more than me the author of this paper could really claim originality as I'm sure the objection is as old as the first claims of thrust/power>1/c... he is just putting it black on white, which has the merit of serving as a later reference. Though may be, as a reference, it would have benefited from a longer bibliography... and yes I would have appreciated a small citation (provided the author was aware of my communication efforts here).

My only original contribution on this line of refutation might be to illustrate how to put the break even velocity Vbe at 1/(thrust/power) rather than 2/(thrust/power) for Newtonian mechanics, i.e. low speeds, for instance with thrust/power=1N/kW yielding a Vbe of 1km/s instead of 2km/s, the CoE apparent breaking appears at more modest velocities when considering constant thrust/constant velocity rather than acquired velocity relative to starting frame. Even that I remember having seen elsewhere. This should appear in the paper, but maybe the author don't care about polishing the argument thus far, as from "this is breaking CoE" standpoint, Vbe=2/(thrust/power) is good enough.

Anyway, apart from Mach effect (Woodward) and QV plasma (White) contenders, both approaches being somehow compatible with tapping in a practically limitless energy source, and making possible a device such as the one depicted above (which is more or less publicly acknowledged by some followers), I saw none convincing argument that it could be possible to render compatible
1/ a working propellantless drive with averaged thrust/power>>1/c (useful for deep space flight)
2/ that don't act as a limitless energy source (for all practical purpose)
That is, for those wanting 1/ and 2/ : what would make the above depicted device fail (or equivalently, what would be the flaw in the cited paper) ? Obviously, just claiming that it does 1/ and still respects 2/ is not convincing by itself when those aspect are treated inconsistently.

It is to be expected as propellantless propulsion phenomenological claims gain in attention that more and more sceptics find the motivation to publish refutations that otherwise would have been kept in the realm of polite pass over. Unfortunately there is still not enough incentive right now for big labs to hunt for experimental null results. What is the point to confirm the inexistence of something that the overwhelming majority of establishment is knee jerkedly considering bogus ? When (if) apparent positives pile up, then this incentive will rise and maybe we will start to see more null results published. I'm convinced there are already a lot of null results out there, just not published/advertised.

ps. Thanks rfmwguy & dr Rodal, et al.  :D

So that's the end of that then?

Offline zellerium

  • Full Member
  • *
  • Posts: 171
  • Pittsburgh, PA
  • Liked: 279
  • Likes Given: 400
...
Regarding space-time. Believe me when I tell you, what we are doing here with attenuation and superposition of EM waves "is" modifying space-time at this narrow bandwidth of the EM spectrum. It is NOT in any way going to generate a gravitational field where clocks, rulers, or lasers will be affected. What is going on at the microwave frequencies close to the cut-off is conceptually, and physically the same as-if space-time were curved at these frequencies. If you try to curve space-time at "all" the frequencies of the ZPF spectrum, such that it affects protons, etc.., the amount of energy required is enormous, as GR will tell you. Having a frequency dependent metric is something I predicted at least 15 years ago, when I first started modeling the PV as a quantum field theory. I had no idea how to do it back then. Now we do! :)

Todd

I like where you are going with this.

But what do you make of Eaglework's results, when they measured "space-time contractions" using a 632.8 nm laser? Isn't this far from bandwidth of the RF signal used?   
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1362403#msg1362403
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1355764#msg1355764

Also Dr. Rodal:
Doesn't a TM mode require the RF feed from the end plates? Or does a magnetron antenna work differently?


Offline deltaMass

  • Full Member
  • ****
  • Posts: 955
  • A Brit in California
  • Liked: 671
  • Likes Given: 275
Apart from the F = P/v (trash Einstein) and F = constant (trash Noether) dynamic models, I did propose a third model which is probably best named "frustrated momentum". In this case, the static F persists until a certain momentum value has been established, equal to an initial impulse given to the system. This momentum having been fully established, F returns to zero Newton.

Shawyer's video seems to fit the "frustrated momentum" bill. McCullough's theory also predicts it IIRC.

Offline rfmwguy

  • EmDrive Builder (retired)
  • Senior Member
  • *****
  • Posts: 2165
  • Liked: 2681
  • Likes Given: 1124
Well goup, I'm taking the plunge...right now. At the risk of being ridiculed by my wife, and maybe a couple on these threads ;), I have attached a Preliminary rev of my proposed emdrive experiment. I welcome any constructive comments, corrections and suggestions. I am putting it out in rough/prelim form to elicit feedback before I get underway in earnest this summer.

In addition, it might motivate others out there to get busy themselves!

p.s. Special thanks to Zellerium for "inspiration" on the experiment outline...

Note: My approach is not to replicate. I've decided on a lower power model for reasons stated in the paper. Nothing written yet has precluded the use of these lower power levels. Perhaps my humble efforts might help with that aspect.

Dave

Tags: