Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1585798 times)

Online Rodal

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This is a thread - Thread 3 in the series - focused on objective analysis of whether the EM Drive (a truncated conical cavity resonating at microwave frequencies) reported "thrust force" is an experimental artifact or whether it is a real propulsion effect  that can be used for space applications, and if so, in discussing those possible space propulsion applications.

Objective skeptical inquiry is strongly welcome, however disagreements must be expressed politely, concentrating on the technical, engineering and scientific aspects, and never focusing on persons involved.   As such, the use of experimental data, mathematics, physics, engineering, drawings, spreadsheets and computer simulations are strongly encouraged, while overly broad subjective wordy statements are discouraged. Peer-reviewed information from reputable journals is strongly encouraged.

Commercial advertisement is discouraged.

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--

Links to previous threads:

Thread 1:
http://forum.nasaspaceflight.com/index.php?topic=29276.0

Thread 2:
http://forum.nasaspaceflight.com/index.php?topic=36313.0

Entry level thread:
http://forum.nasaspaceflight.com/index.php?topic=37438.0

--

Baseline NSF Article:
http://www.nasaspaceflight.com/2015/04/evaluating-nasas-futuristic-em-drive/



This is the link to the EM Drive wiki that all users are encouraged to contribute to, edit for accuracy, and build as a knowledge resource for the EM Drive:

http://emdrive.wiki




Chris note: Please note all posts need to be useful and worthwhile or they will be removed via moderation. This subject has large interest, with over 1.5 million thread reads and 600,000 article reads. Most people are reading and not posting, so when you post it is in front of a very large audience.

Also, and it should go without saying, amateur experiments are discouraged unless you have gained educated and/or professional advice for safety reasons.

« Last Edit: 06/15/2015 01:30 PM by Rodal »

Offline zen-in

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...

I refer to Feynman:


"If it [theory] disagrees with experiment it is wrong."

Yet the trust of this forum seems to be to reject Shawyer and Chinese theory, which matches their experimental results, and seek some new theory outside physics when all that is needed is to listen to Shawyer and the Chinese and apply existing theory in a non conventional way.

...
Concerning Feynman, I was educated in the same institution where he studied, under the same scientific principles and approach.  I performed experiments since I was a freshman (I was lucky that they had started the Undergrad Research Opportunity Program and immediately engaged in hybrid chemical rocket propulsion experiments) at that institution until I got my Ph.D.  Nobody at that institution performs experiments following a single researcher's publications as if they were a holy book.

Feynman's famous Lectures, and his professional life, teaches an approach to physical problems that is the diametrical opposite of following a single researcher as a Guru or a Prophet, whose publications have to be revered, obeyed and followed as a religious book. 

Concerning this thread its focus is on an objective, skeptical attitude trying to ascertain whether the experimental reports are an artifact or a real propulsion effect and if so whether they can be used for space applications, and also discussing those possible space propulsion applications.

If Feynman was a teenager today his curiosity would likely drive him to build an em-drive.    But there is little scientific method in the em-drive experiments.    The good results that have been published in media that is not peer reviewed were all cherry picked from countless experiments.   There has been no accounting of the percentage of experimental results that produced a thrust signature.   Our friend in Romania,  Berca Iulian, is one of the only exceptions to this.   His first experiment, a pendulum, produced no measurable thrust.   His second, a cantilevered contraption for indicating upward thrust did produce a consistent measurement.   However when he flipped it over the thrust almost disappeared and after the magnetron was powered off the fustrum weight decreased.  "The tests  shows that after power off the frustum weight is continue to decrease. up to 0.30 grams at least. How we can explain this ?" (from his blog)   This observation appears to be universal with the em-drive:  After a lot of careful fiddling and adjustments a thrust is measured.   Flip the thing over or do some other significant rearrangement and the thrust practically disappears.    While these experiments do not follow the scientific method and can be individually rejected, the cumulative results provide more reliable evidence of what is happening; ie: nothing.

Note to interested experimenters:  Magnetrons are dangerous.   The radiation can make you blind and the voltages are lethal.

http://www.masinaelectrica.com/emdrive-independent-test/
http://en.wikipedia.org/wiki/Electromagnetic_radiation_and_health
« Last Edit: 05/23/2015 08:47 PM by zen-in »

Offline TheTraveller

I'm not a physicists, mathematician nor microwave engineer. But I am an engineer, that has some ham radio experience and can see, learn from and follow what Roger Shawyer is sharing. My pathway to replication is as follows:

1) Create an Excel spreadsheet that models the 4 physical to thrust parameters as per Shawyer's equations and explanations and confirm thrust predictions against existing experimental data. Ok a BIG ask but doable.

2) Arrange frustum big and small end plate diameters to achieve highest Df, with smallest slant angle at the desired external applied Rf wavelength.

3) Get TM mode E field frustum end plate to end plate 1/2 wave resonance (TM01 equivalent) at the numerically integrated guide wavelength along the cavity length as per the constantly varying frustum diameters.

4) Repeat 2 & 3 until the optimal configuration is achieved.

5) Cut metal & build a narrow band programmable Rf generator wavelength and output subsystem.

6)  Apply Rf, via coax feed, at the optimal wavelength and excite the frustum in TM mode so the E field is centred in and propagates from end plate to end plate of the frustum.

7) Adjust the Rf wavelength and TM mode excitation antenna position inside the frustum to get the best excitation & matched frustum / Rf amp impedances

8) Make thrust measurements using either a Teeter Totter balance beam or direct measurements sitting on a scale in Up, Down and Sideways orientation, inside a sealed box that is also a Faraday Cage as per the attachment.

6) Publish the results.
« Last Edit: 05/23/2015 05:49 PM by TheTraveller »
"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

This really needs to lead off a new thread:



Should point out Nick Breeze did the 3 earlier Shawyer interviews:

1)

2)

3)
« Last Edit: 05/23/2015 06:14 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline kdhilliard

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Brand new. Interview with the inventor of EmDrive. Good info in there.



Quote from: From 2:40
No, EmDrive does not break Newton's Laws.  In fact, it works because of Newton's Third Law.  EmDrive produces thrust in one direction, and if it's allowed to, it will accelerate in the opposite direction.  Momentum is conserved by this process.  And that's what Newton's Third Law is looking for.  In fact, EmDrive is based purely on classic physics -- the physics of Maxwell, Newton, and Einstein.  There is really no need to bring in exotic physics to explain EmDrive.  We don't need quantum vacuum plasma effects, and it is most certainly not a warp drive.
Quote from: From 3:48
No, it is not reactionless.  It is propellantless, or propellant-free perhaps, but in real life there is no such thing as a reactionless drive.  Newton doesn't allow for it and I don't attempt to build one.
I hear what he says, but I sure don't understand how he claims conservation of momentum, particularly since he does not attempt to invoke any exotic interaction with the vacuum plasma.

Quote from: From 4:25, mirroring some concerns which have been expressed here
And there are also a growing number of university departments and private individuals who are trying to replicate our first experiments.  This is of concern because an EmDrive is a potentially lethal device, particularly if you are close to measuring reasonable amounts of thrust it means you have a very high Q cavity, you are putting in significant amount of input power, and this makes it quite dangerous.  So the way to handle the device is the way that I learnt in my early career as a defense contractor.  You must devise rigorous, strict, and knowledgeable safety procedures before you start experimenting with EmDrive.  It has the potential to kill you, and you must obviously bear this in mind.  It's great fun, and it's very tempting to rush in and test it, but you must consider the safety aspects before you do this. 

He seems like a friendly guy.  I'll love to have the chance to sit down with him for a couple of minutes and pose a few simple questions.

~Kirk

Offline StrongGR

I post again my paper where a proof is given that thrust could arise from space-time as shown from general relativity. I am preparing the version to post on arxiv and working through a numerical analysis of the final equation.

Offline deltaMass

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@TheTraveller: Come on. Just six little numbers is all I ask, to verify your claim that Shawyer's equations predict correctly the thrust value.
Actually seven because #4 should be
4. operating frequency and power

and two more if you really want to include curvature (although only one is necessary in order to deduce the second one)
« Last Edit: 05/23/2015 06:16 PM by deltaMass »

Offline TheTraveller

@TheTraveller: Come on. Just six little numbers is all I ask, to verify your claim that Shawyer's equations predict correctly the thrust value.
Actually seven because #4 should be
4. operating frequency and power

and two more if you really want to include curvature (although only one is necessary in order to deduce the second one)

It is Shawyer that claims his thrust equations correctly predict the thrust value.

My goal is to be able to eventually do the same thing.

When I have a spreadsheet that predicts the measured Flight Thruster thrust versus power input, from the guestimated dimensions, I'll post it for all to use.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline deltaMass

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I post again my paper where a proof is given that thrust could arise from space-time as shown from general relativity. I am preparing the version to post on arxiv and working through a numerical analysis of the final equation.
I think eqn 60, the final expression for the thrust, would benefit from pulling out the common factors of the two terms. This makes it more readable and more understandable also.

Offline deltaMass

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@TheTraveller: Come on. Just six little numbers is all I ask, to verify your claim that Shawyer's equations predict correctly the thrust value.
Actually seven because #4 should be
4. operating frequency and power

and two more if you really want to include curvature (although only one is necessary in order to deduce the second one)

It is Shawyer that claims his thrust equations correctly predict the thrust value.

My goal is to be able to eventually do the same thing.

When I have a spreadsheet that predicts the measured Flight Thruster thrust versus power input, from the guestimated dimensions, I'll post it for all to use.
Apologies - I had understood you to be stating a fact rather than quoting reported speech.

Offline txdrive

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Well, I'm in the following group:

1: Shawyer's paper is completely confused. Right at the start he attributes the force to a greater radiation pressure upon the wide end, yet it pushes itself small end forward; this is based upon a completely confused discussion of reaction forces and thrust. This notion that there would be no force on the side walls "according to Maxwell's equations" is simply flat-out wrong. Maxwell's equations, as applied, yield zero thrust; the force on the side walls precisely balances out the pressure difference between the ends. (They're also Lorentz invariant so there's no special relativity corrections to be made)

2: All explanations where the measured force is impacted upon the cavity walls by incident electromagnetic radiation are likewise wrong, whenever they involve speculations about the quantum vacuum or not. The measured force corresponds to the incident electromagnetic radiation deviating from conventional predictions by >50% (Shawyer, Chinese results), or >2.5% (EW results), which is in gross contradiction to experiments that measure electromagnetic radiation directly (many are precise to parts per billion or better).

3: Regarding EW's experiments, their readings contradict each other (when flipped 180 degrees). Other experiments are substantially worse still, with high voltage wires, stiff waveguides being heated, etc. pushing the cavity mechanically.

What results do you expect to get if there's no thrust but you got a bunch of high voltage wires, substantial heat, electrical current in the wires, and vibration? You can't seriously expect to get a literal zero.
« Last Edit: 05/23/2015 06:34 PM by txdrive »

Offline TheTraveller

Thanks to the help of Chris, here is an EM Drive opinion poll:
http://forum.nasaspaceflight.com/index.php?topic=37644.0
« Last Edit: 05/23/2015 06:41 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
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Offline Star One

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Well, I'm in the following group:

1: Shawyer's paper is completely confused. Right at the start he attributes the force to a greater radiation pressure upon the wide end, yet it pushes itself small end forward; this is based upon a completely confused discussion of reaction forces and thrust. This notion that there would be no force on the side walls "according to Maxwell's equations" is simply flat-out wrong. Maxwell's equations, as applied, yield zero thrust; the force on the side walls precisely balances out the pressure difference between the ends. (They're also Lorentz invariant so there's no special relativity corrections to be made)

2: All explanations where the measured force is impacted upon the cavity walls by incident electromagnetic radiation are likewise wrong, whenever they involve speculations about the quantum vacuum or not. The measured force corresponds to the incident electromagnetic radiation deviating from conventional predictions by >50% (Shawyer, Chinese results), or >2.5% (EW results), which is in gross contradiction to experiments that measure electromagnetic radiation directly (many are precise to parts per billion or better).

3: Regarding EW's experiments, their readings contradict each other (when flipped 180 degrees). Other experiments are substantially worse still, with high voltage wires, stiff waveguides being heated, etc. pushing the cavity mechanically.

What results do you expect to get if there's no thrust but you got a bunch of high voltage wires, substantial heat, electrical current in the wires, and vibration? You can't seriously expect to get a literal zero.

And you think the professional experimenters, not talking about the DIY versions here, haven't already considered this. You put forward an argument as if this was the first time anyone had thought of these issues. A greater part of the last thread was examining such issues amongst other things.
« Last Edit: 05/23/2015 06:44 PM by Star One »

Online Rodal

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The scientific method is the exact opposite of staking a priori beliefs as expressed in polls.

Scientists and engineers keep open minds while sifting and analyzing data according to the scientific method, and they reach a conclusion only after exhaustive independent replication of experiments.

Quote from: John von Neumann
If one has really technically penetrated a subject, things that previously seemed in complete contrast, might be purely mathematical transformations of each other

« Last Edit: 05/23/2015 06:54 PM by Rodal »

Offline StrongGR

I post again my paper where a proof is given that thrust could arise from space-time as shown from general relativity. I am preparing the version to post on arxiv and working through a numerical analysis of the final equation.
I think eqn 60, the final expression for the thrust, would benefit from pulling out the common factors of the two terms. This makes it more readable and more understandable also.

Thanks for pointing this out. I did it in the new version that I hope to post here in a few days.

Offline dustinthewind

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Maybe we have a larger than normal non-zero Poynting vector in the sense that the current in the bottom plate is working against the incoming radiation making the bottom plate hot.  The small end appears to reflect better and that might be key.  I will attach a few diagrams and try and relate it to the cavity and show how the light impacting the bottom plate may no be being attenuated by the currents in the bottom plate.  That is the current in the bottom plate might be out of phase with the impacting light by 180 degrees and is instead doing work against the electric field of light. Possibly due to radiation injection near the bottom plate?  This flips the bottom plates mutual repulsion with respect to the top plate or the side walls. 

Could the bottom plates current be doing work against the radiation in the cavity inducing information delay phase based propulsion? (radiation injector is near the bottom plate I noticed.)

If so the forces might be similar to what is presented here: http://arxiv.org/abs/1502.06288

Sorry for the messy middle diagram.  There is allot going on there.  It shows mutual repulsion between two charges but if the bottom charge moves with the top charge then mutual repulsion is violated resulting in a unidirectional force for both charges.

Mutual repulsion could also be violated in the repulsion of an aluminum ring from an AC solenoid if the current in the aluminum ring was driven against the light of the solenoid.  The forces are large and have near field effects.    The repulsion of the aluminum ring can be physically observed. 
« Last Edit: 05/23/2015 07:44 PM by dustinthewind »

Offline txdrive

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Well, I'm in the following group:

1: Shawyer's paper is completely confused. Right at the start he attributes the force to a greater radiation pressure upon the wide end, yet it pushes itself small end forward; this is based upon a completely confused discussion of reaction forces and thrust. This notion that there would be no force on the side walls "according to Maxwell's equations" is simply flat-out wrong. Maxwell's equations, as applied, yield zero thrust; the force on the side walls precisely balances out the pressure difference between the ends. (They're also Lorentz invariant so there's no special relativity corrections to be made)

2: All explanations where the measured force is impacted upon the cavity walls by incident electromagnetic radiation are likewise wrong, whenever they involve speculations about the quantum vacuum or not. The measured force corresponds to the incident electromagnetic radiation deviating from conventional predictions by >50% (Shawyer, Chinese results), or >2.5% (EW results), which is in gross contradiction to experiments that measure electromagnetic radiation directly (many are precise to parts per billion or better).

3: Regarding EW's experiments, their readings contradict each other (when flipped 180 degrees). Other experiments are substantially worse still, with high voltage wires, stiff waveguides being heated, etc. pushing the cavity mechanically.

What results do you expect to get if there's no thrust but you got a bunch of high voltage wires, substantial heat, electrical current in the wires, and vibration? You can't seriously expect to get a literal zero.

And you think the professional experimenters, not talking about the DIY versions here, haven't already considered this. You put forward an argument as if this was the first time anyone had thought of these issues. A greater part of the last thread was examining such issues amongst other things.
I don't think many competent physicists have any interest in Shawyer's theories. What he's writing is so wrong it is painful to read. Experimental physics requires, at least, good knowledge of mechanics, and the glaring bit about the pressure puts anyone with such knowledge off.
« Last Edit: 05/23/2015 07:06 PM by txdrive »

Offline txdrive

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The scientific method is the exact opposite of staking a priori beliefs as expressed in polls.

Scientists and engineers keep open minds while sifting and analyzing data according to the scientific method, and they reach a conclusion only after exhaustive independent replication of experiments.

Quote from: John von Neumann
If one has really technically penetrated a subject, things that previously seemed in complete contrast, might be purely mathematical transformations of each other


Keep in mind that for most claims there's a huge body of pre-existing well replicated experiments. A claim that EM radiation in a cavity differs from conventional calculations by 2.5% would be an example of such a claim.

Offline jmossman

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(...)
My pathway to replication is as follows:

1) Create an Excel spreadsheet that models the 4 physical to thrust parameters as per Shawyer's equations and explanations and confirm thrust predictions against existing experimental data. Ok a BIG ask but doable.

(....)

8 ) Make thrust measurements using either a Teeter Totter balance beam or direct measurements sitting on a scale in Up, Down and Sideways orientation, inside a sealed box that is also a Faraday Cage as per the attachment.

6 9) Publish the results.

More experimental data would be a huge benefit to the effort.  BTW, excellent sleuthing with trying to distill Shawyer's thoughts into an equation of any kind;  time will tell if Shawyer's equation(s) and explanations are valid approximations for the phenomena or not.  Lot's of potentially mundane sources for "thrust", so a repeatable experiment will allow the scientific community to dissect into pieces to confirm/deny the true source(s).

IMO, the lack of repeatable data is the biggest problem.  Solve that issue, and the rest will fall into place. 

Go experiments, go!   ;)

-James

Offline TheTraveller

Quote from: txdrive
I don't think many competent physicists have any interest in Shawyer's theories. What he's writing is so wrong it is painful to read. Experimental physics requires, at least, good knowledge of mechanics, and the glaring bit about the pressure puts anyone with such knowledge off.

Yet both Shawyer and the Chinese claim their theories closely calculate the value of their measured thrust? Surely that must open the possibility of their unconventional application of classic theory being correct and that no new physics is involved nor needed?

« Last Edit: 05/23/2015 07:31 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

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