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General Discussion => New Physics for Space Technology => Topic started by: Rodal on 05/23/2015 05:01 PM

Title: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/23/2015 05:01 PM
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.

In order to minimize bandwidth and  maximize information content, when quoting, instead of a whole quotation please try to quote only the relevant phrases, and use an ellipsis (...) to indicate the clipped material.

Only use the embed [img ]http://code when the image is small. Anything wider than the width of the thread makes the page unreadable as it stretches it (we're working on auto reduction, but different browsers work different ways, etc.)

This link

http://math.typeit.org/

enables typing of mathematical symbols, including differentiation and integration, Greek letters, etc.


--

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.

(https://peninkandpaper.files.wordpress.com/2013/09/be-careful-safety-first-sign-s-4115.gif)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zen-in on 05/23/2015 05:38 PM
...

I refer to Feynman:
https://www.youtube.com/watch?v=kctmPaCkV0g

"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
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/23/2015 05:41 PM
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.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/23/2015 05:52 PM
This really needs to lead off a new thread:

https://www.youtube.com/watch?v=4hTdSg47h3k

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

1) https://www.youtube.com/watch?v=GGTjy6atKMs

2) https://www.youtube.com/watch?v=xmfPNuhy0mc

3) https://www.youtube.com/watch?v=l2dwC5Am42Q
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kdhilliard on 05/23/2015 05:53 PM
Brand new. Interview with the inventor of EmDrive. Good info in there.

17:57 YouTube video: Full interview: Roger Shawyer, Creator of EmDrive (https://www.youtube.com/watch?v=4hTdSg47h3k)

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
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/23/2015 05:56 PM
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.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/23/2015 06:11 PM
@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)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/23/2015 06:21 PM
@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.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/23/2015 06:22 PM
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.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/23/2015 06:23 PM
@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.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: txdrive on 05/23/2015 06:26 PM
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.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/23/2015 06:39 PM
Thanks to the help of Chris, here is an EM Drive opinion poll:
http://forum.nasaspaceflight.com/index.php?topic=37644.0
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/23/2015 06:43 PM
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.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/23/2015 06:53 PM
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

(https://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/JohnvonNeumann-LosAlamos.gif/220px-JohnvonNeumann-LosAlamos.gif)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/23/2015 06:58 PM
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.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: dustinthewind on 05/23/2015 06:58 PM
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. 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: txdrive on 05/23/2015 07:04 PM
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.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: txdrive on 05/23/2015 07:11 PM
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

(https://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/JohnvonNeumann-LosAlamos.gif/220px-JohnvonNeumann-LosAlamos.gif)
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.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: jmossman on 05/23/2015 07:18 PM
(...)
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
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/23/2015 07:25 PM
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?

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/23/2015 07:38 PM

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.

I'm less interested in the theories than the practical results at this stage in time. Attempts at explanations should not hinder the experimental investigation. Just because no one has put a widely accepted theory together yet should dissuade scientific investigation.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kdhilliard on 05/23/2015 07:47 PM
Brand new. Interview with the inventor of EmDrive. Good info in there.

17:57 YouTube video: Full interview: Roger Shawyer, Creator of EmDrive (https://www.youtube.com/watch?v=4hTdSg47h3k)

That was done by the same guy who posted a 50 minute recording of an impromptu presentation by Shawyer last year.

13:58 YouTube video: EmDrive Presentation by Roger Shawyer Part 1 of 3 (https://www.youtube.com/watch?v=GGTjy6atKMs)
14:49 YouTube video: EmDrive Presentation by Roger Shawyer Part 2 of 3 (https://www.youtube.com/watch?v=xmfPNuhy0mc)
23:03 YouTube video: EmDrive Presentation by Roger Shawyer Part 3 of 3 (https://www.youtube.com/watch?v=l2dwC5Am42Q)

These offer a good introduction to Shawyer's ideas, but without any mathematical formulas.  They don't have any live video, but instead show slides.  It was recorded in a cafe and there is a lot of background noise, but it is sill easy to make out all that Shawyer says.

I listened to these last night hoping to glean some hints that would explain Shawyer's reasoning for why he expects the drive to accelerate small end first.

Quote from: Part 1, 0:33
What the EmDrive thruster does is to produce a force, which we call the thrust, in one direction.  This is a force that you can measure.  If you put your hand against the end plate that's producing the thrust you'll feel it pushing against you.  And, as with all machines that follow Newton's principles, it will therefore accelerate in the opposite direction.  So this is not a reactionless thruster, because those things just don't exist outside of science fiction, but it is a propellantless thruster.

That leaves me bewildered as to his thought process.  I hear what he says about feeling the force of the large end plate against your hand, but how does that make the drive accelerate in the other direction when it should just balance forces to hold the drive in place until you pull your hand out of the way and let it accelerate large end first?

By analogy, consider a ping pong ball being held underwater in a pool.  The force exerted by the water pressure onto the ball's surface increases with depth, so the upward forces on the lower portions of the ball are greater than the downward forces on its upper portions, resulting in a net upward force.  Your stationary  hand on top of the ping pong ball feels this force, and acts to keep the ball from accelerating upward, but it doesn't cause the ball to accelerate downward, and I'm sure that Shawyer wouldn't claim that it would.

I guess this bothers me so much because Shawyer sounds like a smart guy, and this appears to be such a simple and obvious contradiction of logic that there must be more to his argument.  (Unless he's just pulling our legs.)


Traveller, you seem to be the one here most familiar with Shawyer's works.  Do you follow his line of reasoning?

~Kirk
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/23/2015 08:03 PM
This is what happens when a smart person is faced with data that is irreconcilable with known physics. They know that they are expected to explain it, and they also know that they cannot. In this case Shawyer simply babbles nonsense (and I'm putting that as kindly as I can without resorting to insult). It's cognitive dissonance in the flesh.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/23/2015 08:11 PM

This is what happens when a smart person is faced with data that is irreconcilable with known physics. They know that they are expected to explain it, and they also know that they cannot. In this case Shawyer simply babbles nonsense (and I'm putting that as kindly as I can without resorting to insult). It's cognitive dissonance in the flesh.

If there's anything this I wouldn't bet on it being outside known physics, rather known physics but in a different way if that makes sense.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/23/2015 08:13 PM
Not really :). If it were known physics, you could tell us all about it!
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/23/2015 08:40 PM
I just opened my box of Mechanics books.  I found Maxwell's book

Matter and motion
by James Clark Maxwell

Notes and appendices by Sir Joseph Larmor
Cambridge University, 1920

page 40

The Third Law of Motion

Law III. Reaction is always equal and opposite to action, that is to say, the action of two bodies upon each other are always equal and in opposite directions.

When the bodies between which the action takes place are not acted on by any other force, the changes in their respective momenta produced by the action are equal and opposite directions.

The changes in the velocities of the two bodies are also in opposite directions, but not equal, except in the case of equal masses.  In other cases the changes of velocity are in the inverse ratio of the masses.

(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=776944;image)

Following D'Alembert's convention of fictional inertial forces.  See  http://forum.nasaspaceflight.com/index.php?topic=37642.msg1378839#msg1378839  for the more usual convention

So, Shawyer has two forces that he says follow Newton's 3rd law, and Shawyer says that he follows Maxwell

then, from the image above, you must have

Summation of forces = 0

Reaction force vector is in opposite direction to Thrust force vector.  Hence they have opposite sign.

Reaction - Thrust =0 (essentially Shawyer shows a D'Alembert's Free-Body-Diagram  https://en.wikipedia.org/wiki/D%27Alembert%27s_principle where the forces sum up to zero)

Reaction = Thrust

assign a portion of the mass of the truncated cone to the Reaction force and the other portion to the Thrust force

massReaction + massThrust =total mass

then

massReaction*accelerationReaction = massThrust*accelerationThrust

imagine that the truncated cone is split apart as a gun and a bullet, essentially when you turn on the power to the EM Drive there is an explosive force inside the sends the Small End and the Big End in opposite directions,

In that case the Reaction is the force on the bullet (the Small End) and the Thrust (force on the Big End) is the recoil force on the gun, then acceleration of the bullet is

accelerationBullet = (massGun/massBullet)*recoilAccelerationGun

(the recoil acceleration is in opposite direction to the bullet acceleration)

no problem with understanding that.  However, the EM Drive remains as one EM Drive (it does not separate into two wagequides), therefore we must have :

accelerationThrust = - accelerationReaction = accelerationEMDrive

(both the acceleration of the Big End and the Small End are in the same direction)

massReaction*accelerationEMDrive= massThrust*(-accelerationEMDrive)

therefore:

massReaction = -  massThrust

in other words, for what Shawyer claims that happens to happen, one must have the mass associated with the Thrust force to be negative mass

According to his theory, separating the EM Drive into two distinct waveguides (instead of one closed cavity), one waveguide is associated with the Big End and the other waveguide is associated with the Small End.  Then for the small end to accelerate with the Reaction Force, that means that the portion of the total mass associated with the Thrust force, the mass of the Big End waveguide, must have negative mass.

and the total mass of the EM Drive must be zero:

massReaction + massThrust = total mass

                                           = 0



Again:

1) Mass of waveguide associated with the Small End is positive, normal mass

2) Mass of waveguide associated with the Big End is negative, exotic mass

3) Total mass of EM Drive cavity is zero.



Conclusion: unless the total mass of the EM Drives being experimented by Shawyer is zero, and a portion of their mass (associated with the Big End) is negative, exotic mass, his theory cannot explain what is being claimed


Quote from: Wolfgang Pauli
not even wrong
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/23/2015 08:51 PM
Interesting. Maybe he should have a chat with Professor Woodward  8)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: CW on 05/23/2015 09:03 PM

(...)

Reaction - Thrust =0 (essentially Shawyer shows a Free-Body-Diagram where the forces sum up to zero)

(...)

Dear Dr. Rodal,

If, as you write, the following is supposed to be true:

   Reaction - Thrust = 0        | with Thrust, according to Newton, being equal to (-Reaction), then it follows

   Reaction - (-Reaction) = 0        or
   Reaction + Reaction = 0

That cannot be right. Once the arrow or vector convention is set, all vectors must be treated equally. Vectors are simply added. Vector subtraction a-b is also just vector addition a+(-1)*b .

The equation should be    Reaction + Thrust = 0 , under the premise that anyone even gives a darn about conventions anymore.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/23/2015 09:09 PM
(...)
therefore:

massReaction = -  massThrust

in other words, for what Shawyer claims that happens to happen, one must have the mass associated with the Thrust force to be negative mass

According to his theory, separating the EM Drive into two distinct waveguides (instead of one closed cavity), one waveguide is associated with the Big End and the other waveguide is associated with the Small End.  Then for the small end to accelerate with the Reaction Force, that means that the portion of the total mass associated with the Thrust force, the mass of the Big End waveguide, must have negative mass.

and the total mass of the EM Drive must be zero:

massReaction + massThrust = total mass

                                           = 0



Again:

1) Mass of waveguide associated with the Small End is positive, normal mass

2) Mass of waveguide associated with the Big End is negative, exotic mass

3) Total mass of EM Drive cavity is zero.



Conclusion: unless the total mass of the EM Drives being experimented by Shawyer is zero, and a portion of their mass (associated with the Big End) is negative, exotic mass, his theory cannot explain what is being claimed


Quote from: Wolfgang Pauli
not even wrong

The "effective mass" term is proportional to 1/cut-off-wavelengths at each end. If we define the baseline at the small end, the "relative" effective mass at the big end is negative.

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: txdrive on 05/23/2015 09:09 PM
The other way to put it - we can actually set up a situation where radiation pressure upon the big end is greater than that upon the little end. In space, put a flashlight inside the cavity, pointed upon the big end (which is not perfectly reflective). The radiation pressure upon the big end will be greater than that upon the small end, and the cavity will accelerate big end forward.

(The flashlight, if unsupported, will move in the opposite direction, like a photon rocket, but it could in principle be held in place, e.g. using magnetic levitation)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: dustinthewind on 05/23/2015 09:15 PM

1) Mass of waveguide associated with the Small End is positive, normal mass

2) Mass of waveguide associated with the Big End is negative, exotic mass
...


Quote from: Wolfgang Pauli
not even wrong

I think that is effectively the concept behind phased based propulsion.  The current working with the electric field of light, say at the top of the cavity, provides normal repulsion due to the changing magnetic field (or the currents resistance to encountering a changing magnetic field makes a counter current).  Counter currents repel.  If at the bottom the current may be working against the electric field of light and we don't get repulsion as the small end.  Rather the bottom experiences attraction which is opposite of the normal repulsion due to changing magnetic fields (the light appears to have negative mass and attracts the bottom plate).  I am not saying this is what is happening but I suspect it is a possibility. 

I think if it was happening the bottom plate might lose its Q and heat up more so than the top part.  Is the ratio of heat on the bottom plate in ratio to the top as it should be? 

The drive still has positive mass and resists being accelerated but the effective mass of the radiation and near field should be imbalanced in effective mass from front to back. 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: txdrive on 05/23/2015 09:20 PM
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?
It's like you come across some "make money online" ad, and they're claiming that their earnings match their calculations, which have glaring arithmetical errors. Anyone can claim anything.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/23/2015 09:37 PM
...
The equation should be    Reaction + Thrust = 0 , under the premise that anyone even gives a darn about conventions anymore.
I'm trying to interpret Shawyer's diagram using D'Alembert's principle.  I cannot make sense of his "convention" for his force construction to work.  Maybe something is lost in translation or my imagination is not good enough to understand what he is showing.

His force convention does not follow any of the books I have in Mechanics (the fact that he has these two equal an opposite forces which should result in a body in equilibrium, hence having no acceleration).
It leads to a contradiction whatever way I adopt for a consistent convention.


Let's say that we instead interpret Shawyer as you suggest.

Then work out the bullet/gun split: one comes up with the accelerations having different signs which I agree is a more conventional view.  If one consistently follows the same convention all the way through, (since the bullet and the gun both have real positive masses), then one ends up with the same result I have above that the mass of the Big End is the negative of the mass of the Small End and that the Total Mass of the EM Drive must be zero, for  Shawyer's construction to hold in an EM Drive that does not split apart and accelerates as unit in one direction.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/23/2015 09:38 PM
The other way to put it - we can actually set up a situation where radiation pressure upon the big end is greater than that upon the little end. In space, put a flashlight inside the cavity, pointed upon the big end (which is not perfectly reflective). The radiation pressure upon the big end will be greater than that upon the small end, and the cavity will accelerate big end forward.

(The flashlight, if unsupported, will move in the opposite direction, like a photon rocket, but it could in principle be held in place, e.g. using magnetic levitation)

Is what I'm hearing is that Shawyer is saying: In space I can literally push against the windshield with a flashlight, but not with my hand, and get thrust?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: CW on 05/23/2015 09:48 PM
...
The equation should be    Reaction + Thrust = 0 , under the premise that anyone even gives a darn about conventions anymore.
I'm using D'Alembert's principle looking at Shawyer's diagram.  His force convention does not follow any of the books I have in Mechanics (the fact that he has these two equal an opposite forces which should result in a body in equilibrium, hence having no acceleration).


Let's say that we instead interpret Shawyer as you suggest.

Then work out the bullet/gun split: one comes up with the accelerations having different signs which I agree is a more conventional view.  If one consistently follows the same convention all the way through, for the bullet and the gun to both have real positive masses, then one ends up with the same result I have above that the mass of the Big End is the negative of the mass of the Small End and that the Total Mass of the EM Drive must be zero, according to Shawyer.

I fear that the available documents from Mr. Shawyer are unusable for any reasonable discussion. Judging by the available reports of a number of groups telling that something seems to or is going on, I feel that Mr. Shawyer might have found something by sheer coincidence. It reminds me of the logical implication that tells us that starting from a wrong premise, any conclusion is possible - even the right one.
;)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/23/2015 09:54 PM

...
The equation should be    Reaction + Thrust = 0 , under the premise that anyone even gives a darn about conventions anymore.
I'm using D'Alembert's principle looking at Shawyer's diagram.  His force convention does not follow any of the books I have in Mechanics (the fact that he has these two equal an opposite forces which should result in a body in equilibrium, hence having no acceleration).


Let's say that we instead interpret Shawyer as you suggest.

Then work out the bullet/gun split: one comes up with the accelerations having different signs which I agree is a more conventional view.  If one consistently follows the same convention all the way through, for the bullet and the gun to both have real positive masses, then one ends up with the same result I have above that the mass of the Big End is the negative of the mass of the Small End and that the Total Mass of the EM Drive must be zero, according to Shawyer.

I fear that the available documents from Mr. Shawyer are unusable for any reasonable discussion. Judging by the available reports of a number of groups telling that something seems to or is going on, I feel that Mr. Shawyer might have found something by sheer coincidence. It reminds me of the logical implication that tells us that starting from a wrong premise, any conclusion is possible - even the right one.
;)

I agree. Even with my limited understanding I've been left scratching my head.:)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/23/2015 09:59 PM
Following Newton's 2nd Law convention this time

Matter and motion
by James Clark Maxwell

Notes and appendices by Sir Joseph Larmor
Cambridge University, 1920

page 40

The Third Law of Motion

Law III. Reaction is always equal and opposite to action, that is to say, the action of two bodies upon each other are always equal and in opposite directions.

When the bodies between which the action takes place are not acted on by any other force, the changes in their respective momenta produced by the action are equal and opposite directions.

The changes in the velocities of the two bodies are also in opposite directions, but not equal, except in the case of equal masses.  In other cases the changes of velocity are in the inverse ratio of the masses.

(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=776944;image)

So, Shawyer has two forces that he says follow Newton's 3rd law, and Shawyer says that he follows Maxwell

Reaction = - Thrust

assign a portion of the mass of the truncated cone to the Reaction force and the other portion to the Thrust force

massReaction + massThrust =total mass

then

massReaction*accelerationReaction = - massThrust*accelerationThrust

imagine that the truncated cone is split apart as a gun and a bullet, essentially when you turn on the power to the EM Drive there is an explosive force inside the sends the Small End and the Big End in opposite directions,

In that case the Reaction is the force on the bullet (the Small End) and the Thrust (force on the Big End) is the recoil force on the gun, then acceleration of the bullet is

accelerationBullet = (massGun/massBullet)*(-  recoilAccelerationGun)

(the recoil acceleration is in opposite direction to the bullet acceleration)

no problem with understanding that.  However, the EM Drive remains as one EM Drive (it does not separate into two wagequides), therefore we must have :

accelerationThrust = accelerationReaction = accelerationEMDrive

(both the acceleration of the Big End and the Small End are in the same direction)

massReaction*accelerationEMDrive= - massThrust*accelerationEMDrive

therefore:

massReaction = -  massThrust

in other words, for what Shawyer claims that happens to happen, one must have the mass associated with the Thrust force to be negative mass

According to his theory, separating the EM Drive into two distinct waveguides (instead of one closed cavity), one waveguide is associated with the Big End and the other waveguide is associated with the Small End.  Then for the small end to accelerate with the Reaction Force, that means that the portion of the total mass associated with the Thrust force, the mass of the Big End waveguide, must have negative mass.

and the total mass of the EM Drive must be zero:

massReaction + massThrust = total mass

                                           = 0



Again:

1) Mass of waveguide associated with the Small End is positive, normal mass

2) Mass of waveguide associated with the Big End is negative, exotic mass

3) Total mass of EM Drive cavity is zero.



Conclusion: unless the total mass of the EM Drives being experimented by Shawyer is zero, and a portion of their mass (associated with the Big End) is negative, exotic mass, his theory cannot explain what is being claimed


Quote from: Wolfgang Pauli
not even wrong
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/23/2015 09:59 PM
Finally completed a simple UI.

One thing to add is the ability to enter the small plate diameter - and switch between small plate diameter or design factor and have the other parameter computed and displayed.

Also a toggle for a small end cylinder. :)

Now to start messing with modes.

I prefer this better than a spreadsheet.  I wrote an Excel like spreadsheet years ago and even with the knowledge I have about them find them constricting.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: CW on 05/23/2015 10:32 PM

(...)

So, Shawyer has two forces that he says follow Newton's 3rd law, and Shawyer says that he follows Maxwell

Reaction = - Thrust

assign a portion of the mass of the truncated cone to the Reaction force and the other portion to the Thrust force

massReaction + massThrust =total mass

then

massReaction*accelerationReaction = massThrust*accelerationThrust

(...)

Dear Dr. Rodal,

I believe your're introducing a sign error in your considerations. It looks to me as if you only take the absolute values or norm of 'accelerationReaction' and 'accelerationThrust' and equate them. If Newton's 3rd law is correctly applied, then it is IMHO written

massReaction*accelerationReaction + massThrust*accelerationThrust = 0,   or
massReaction*accelerationReaction = -massThrust*accelerationThrust

Or is there a reason to ignore the vector directions that eludes me? Otherwise I can easily see, why negative mass seemingly arises. If the EM-drive accelerates, it can't have anything to do with Newton's 3rd law. At least not in our measly 3+1 space, IMHO.
;)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/23/2015 11:03 PM

(...)

So, Shawyer has two forces that he says follow Newton's 3rd law, and Shawyer says that he follows Maxwell

Reaction = - Thrust

assign a portion of the mass of the truncated cone to the Reaction force and the other portion to the Thrust force

massReaction + massThrust =total mass

then

massReaction*accelerationReaction = massThrust*accelerationThrust

(...)

Dear Dr. Rodal,

I believe your're introducing a sign error in your considerations. It looks to me as if you only take the absolute values or norm of 'accelerationReaction' and 'accelerationThrust' and equate them. If Newton's 3rd law is correctly applied, then it is IMHO written

massReaction*accelerationReaction + massThrust*accelerationThrust = 0,   or
massReaction*accelerationReaction = -massThrust*accelerationThrust

Or is there a reason to ignore the vector directions that eludes me? Otherwise I can easily see, why negative mass seemingly arises. If the EM-drive accelerates, it can't have anything to do with Newton's 3rd law. At least not in our measly 3+1 space, IMHO.
;)

Yes there was a (-) sign missing in one of the equations in second message:  http://forum.nasaspaceflight.com/index.php?topic=37642.msg1378839#msg1378839

(which I had rapidly copied, and I thought that I had put the minus signs everywhere, but I forgot to put one in that equation)

Thanks. Please let me know whether you find other missing signs.

But in the end, it is not an error in convention, it is an error in Shawyer having two forces for an accelerating body in different directions.  For the body to accelerate, the force has to be in the same direction as the acceleration. 

 A rigid body (that does not break apart or elongates like rubber) cannot have inertial forces in opposite directions. There is where the problem lies

I worked it out both ways, and using consistent conventions (no matter what convention) Shawyer's construction implies zero total mass.

If you can make Shawyer's construction to work, with any convention, I would be delighted to see it, as then we could end the theoretical part of the thread saying , AHA ! we got it, there is no violation of CoM, and the EM Drive can be analyzed with classical physics.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: txdrive on 05/23/2015 11:16 PM
...
The equation should be    Reaction + Thrust = 0 , under the premise that anyone even gives a darn about conventions anymore.
I'm using D'Alembert's principle looking at Shawyer's diagram.  His force convention does not follow any of the books I have in Mechanics (the fact that he has these two equal an opposite forces which should result in a body in equilibrium, hence having no acceleration).


Let's say that we instead interpret Shawyer as you suggest.

Then work out the bullet/gun split: one comes up with the accelerations having different signs which I agree is a more conventional view.  If one consistently follows the same convention all the way through, for the bullet and the gun to both have real positive masses, then one ends up with the same result I have above that the mass of the Big End is the negative of the mass of the Small End and that the Total Mass of the EM Drive must be zero, according to Shawyer.

I fear that the available documents from Mr. Shawyer are unusable for any reasonable discussion. Judging by the available reports of a number of groups telling that something seems to or is going on, I feel that Mr. Shawyer might have found something by sheer coincidence. It reminds me of the logical implication that tells us that starting from a wrong premise, any conclusion is possible - even the right one.
;)
Well, what he stumbled across is neither new nor profound. It is the fact that accurate measurement of forces of roughly the magnitude of the radiation pressure upon a surface, in the presence of said radiation heating the surface being irradiated, is tricky.

edit: I think people here really under-estimate conventional physics, and the ease with which one can stumble upon some perfectly normal forces (that either do not work for accelerating a spaceship, or are already used to that end).
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: LasJayhawk on 05/23/2015 11:34 PM
It seems like we are trying to apply Newtonian physics to something that may be a quantum level effect.

But the thought had occurred to me that when Iulian got less thrust in the down direction, something else might come into play besides hot air. If the force is between his D.U.T and the floor, the difference might be caused by the inverse square law. By eyeball, the big end to floor distance increased by about 125-150%
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Blaine on 05/23/2015 11:52 PM
It seems like we are trying to apply Newtonian physics to something that may be a quantum level effect.

But the thought had occurred to me that when Iulian got less thrust in the down direction, something else might come into play besides hot air. If the force is between his D.U.T and the floor, the difference might be caused by the inverse square law. By eyeball, the big end to floor distance increased by about 125-150%

Yes, but by intensity of what? What exactly are we dealing with? The inverse square law would only make sense if we had some sort of system going.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 12:19 AM
Impedance?

locus of 50+j0
I would have to dedicate some time to write some more code to calculate the Impedance and I lost that motivation when I calculated the average Poynting vector due to the dielectric Tan Delta loss, some time ago.

Perhaps you can elaborate on the reasons why to calculate the Impedance.  ;)

Meanwhile I'm looking at the thermodynamics of this thing.

Waiting to see further data from Iulian, Shawyer's superconducting EM  Drive, Cannae's latest, Prof. Yang, and Paul March's.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Dortex on 05/24/2015 12:50 AM
But the thought had occurred to me that when Iulian got less thrust in the down direction, something else might come into play besides hot air.

Frankly, it's probably mostly hot air in this case. The bigger end is facing up this time, and unless I'm mistaken, the holes are closer the the small end/middle. It can't vent out quite as well as it could last time. I noticed the rsults became unusable after it was turned on a few times.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zaphod_vi on 05/24/2015 12:51 AM
This is a supposed quote from Roger Shawyer that I have copy/pasted.

Quote
What the EmDrive thruster does is to produce a force, which we call the thrust, in one direction. This is a force that you can measure. If you put your hand against the end plate that's producing the thrust you'll feel it pushing against you. And, as with all machines that follow Newton's principles, it will therefore accelerate in the opposite direction. So this is not a reactionless thruster, because those things just don't exist outside of science fiction, but it is a propellantless thruster.

It's a little confusing, but i hope i am not stating the obvious in saying that the interesting part is where he says that if you put your hand against the end plate that's producing the thrust you'll feel it pushing against you. That is, your hand is pushed away from the plate. In which case its behaving similar to a common or garden rocket. i.e. mass is thrown out the back end of the frustrum, which you feel bouncing off your hand. Momentum is conserved, and the frustrum goes in the opposite direction.

As LasJayhawk suggested, it might be an idea if Iulian varied the distance between the thrust plate and the floor if more tests are done.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 12:58 AM
Interesting. Maybe he should have a chat with Professor Woodward  8)
We know Prof. Woodward's opinion from the previous threads, reportedly (as conveyed by others):

1) He thinks that the only reliable tests are the ones performed by NASA with the dielectric, and the reason for the measured thrust was due to Woodward/Mach Effect from the HDPE dielectric.  Ditto for Cannae's drive with the PTFE dielectric.

2) He thinks that an EM Drive without a dielectric insert should not be able to produce thrust, because Prof. Woodward thinks that the law of conservation of momentum negates any such thrust in an empty cavity.

3) He does not think that the Quantum Vacuum plasma hypothesis from Dr. White is viable because the QV is immutable and not degradable, and because one cannot push against the QV.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 12:58 AM
Is there anyone here who can speak to the care and feeding of tapered fibre lasers?
Thank you.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 01:03 AM
This is a supposed quote from Roger Shawyer that I have copy/pasted.

Quote
What the EmDrive thruster does is to produce a force, which we call the thrust, in one direction. This is a force that you can measure. If you put your hand against the end plate that's producing the thrust you'll feel it pushing against you. And, as with all machines that follow Newton's principles, it will therefore accelerate in the opposite direction. So this is not a reactionless thruster, because those things just don't exist outside of science fiction, but it is a propellantless thruster.

It's a little confusing, but i hope i am not stating the obvious in saying that the interesting part is where he says that if you put your hand against the end plate that's producing the thrust you'll feel it pushing against you. That is, your hand is pushed away from the plate. In which case its behaving similar to a common or garden rocket. i.e. mass is thrown out the back end of the frustrum, which you feel bouncing off your hand. Momentum is conserved, and the frustrum goes in the opposite direction.

As LasJayhawk suggested, it might be an idea if Iulian varied the distance between the thrust plate and the floor if more tests are done.
OK, let's think about this. As I understand it, he says that he can feel the force pushing when the BigEnd is not moving.  Let's assume that he very gently places his hand on the BigEnd (because if he pushes it, what he will feel is the inertia of the EM Drive resisting motion).

If the end plate is rigid, then he is feeling some particles. Is he invoking quantum tunneling of photons through the copper? Can he really feel the pressure of photons? I doubt it. Can he feel evanescent waves? I doubt it.

If the end plate is very compliant (a thin copper copper membrane) then he is feeling either vibrations or static bending of the membrane.  This could be produced by classical forces like internal pressure from heated moist air (PV=nRT), or it could be produced by thermal buckling (see my paper), or it could be produced by thermal expansion of a pre-buckled membrane.  Many classical explanations for what he may feel...
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 01:25 AM
(I step out of the playroom for one minute and ....)

Quotes:


The topology is different.  The wave packet in the EM case has the shape and phase distribution set by the cavity.  If the cavity walls disappeared the trajectory of the wave packet would curve in 4-space (accelerate).  It can't do that because the cavity is still there and has much more mass-equivalent than the wavepacket, so all you see is the reaction force.
« Last Edit: 05/23/2015 02:42 PM by Notsosureofit »

OK, I would have to work out the math to convince myself that the "walls dissapeared".  If they dissapeared we are in agreement. But to get there I need a proof, as you said  :)
 05/23/2015 02:43 PM by Rodal

You are still too quick for me !
4-D "curve" is acceleration.  The "holographic" representation is 3-D in the EM cavity.  The fixed plane is time.

It should be reducible to a x,y version w/ z,t in the propagation direction (?) but again the walls must disappear for it to propagate.  ??  does the Poynting vector satisfy that condition if the walls are removed ?  Probably not when I try to visualize it. ? although the standing waves are then propagating waves.  Still sounds like you need to integrate all point spherical waves over the cavity volume using their instantaneous amplitude and phase when the walls disappear.

(Sorry about thinking out loud)
« Last Edit: 05/23/2015 03:14 PM by Notsosureofit »

The only way I can see having a non-zero period-time-averaged Poynting vector in a cavity is either through a nonlinearity (example: Marco Frasca's second order nonlinearity due to GR, or van Tiggelen's 4th order nonlinearity due to magneto-chiral effect), or through an energy gradient (radiative heat transfer, etc.).

The example you gave with the "backbone curve" (as it is known in the literature, where one has a nonlinear spring) is a nonlinearity.
« Last Edit: 05/23/2015 03:33 PM by Rodal »

Of course, if the Poynting vector stays zero then momentum is conserved.  Is that the case in a self-accelerating wavefunction ?  I havn't seen it explicitly mentioned but they do claim CoM.
05/23/2015 03:19 PM » by Notsosureofit

To be specific, let's point out that we are talking about the time-average (over an integer number of periods) of the Poynting vector being zero, as the Poynting vector itself is a non-zero harmonic function of time even as a solution of Maxwell's equations (the Poynting vector in that case having twice the frequency of the electromagnetic field frequency).
« Last Edit: 05/23/2015 03:26 PM by Rodal »

Yes, only the "disappearance" of the wall for mathematical reasons would be instantaneous.
« Last Edit: 05/23/2015 03:31 PM by Notsosureofit »

Quote from: Notsosureofit on 05/23/2015 03:57 PM


FYI

Here we go:

http://physics.technion.ac.il/~msegev/publications/Maxwell_accelerating_beams.pdf

"For both TE and TM polarizations, the beams exhibit shape-preserving bending which can
have subwavelength features, and the Poynting vector of the main lobe displays a turn of more than 90"

"of the main lobe"

In our case the cavity keeps the shape from changing, so we see the force necessary to maintain the Poynting vector.


Added:  in the conclusions...

". To complete
the picture, future work should study the possibility of 3D
accelerating beams, including those with trajectories that
do not lie in a single plane. In practical terms, this work
brings accelerating beam optics into the subwavelength
regime, through the less-than-wavelength features of our
solutions, facilitating higher resolution for particle
manipulation."


« Last Edit: 05/23/2015 04:32 PM by Notsosureofit »

Unquotes:

...


At least on a cylindrical (ie symetrical) cavity, dropping the wall still integrates to a zero Poynting vector over the far-field sphere.  No interesting ramifications yet.

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/24/2015 01:38 AM
Totally off topic, but on a lighter note, if they can get the beams to turn ~90 degrees, does that mean that your laser rifle can shoot around corners?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zaphod_vi on 05/24/2015 01:40 AM
So, in a static test, with the unit powered up, he feels the end plate pushing against his hand (the thrust coming out of it and hitting his hand). Does this mean he doesn't feel the end plate pushing against his hand in a moving test, or that he hasn't tried it, or that his hand isn't sensitive enough in this circumstance, or that it is a bit dangerous to try.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 01:45 AM
Totally off topic, but on a lighter note, if they can get the beams to turn ~90 degrees, does that mean that your laser rifle can shoot around corners?

Maybe.  They claim to be able to scan the beam of a laser welder (I should look that up)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 01:47 AM
(I step out of the playroom for one minute and ....)

....

At least on a cylindrical (ie symetrical) cavity, dropping the wall still integrates to a zero Poynting vector over the far-field sphere.  No interesting ramifications yet.

OK, they get some very interesting, non-intuitive solutions to Maxwell's equations: nondiffracting spatially accelerating solutions, with a Poynting vector that displays a turn of more than 90 degrees. 

Let's say that this would involve an acceleration of the EM Drive when the Poynting vector >0

But then when the Poynting vector < 0 shouldn't the acceleration be in the opposite direction?

And aren't we back to the same situation we are with standing waves in a cavity? : even with standing waves we have a non-zero Poynting vector, the problem is that it keeps switching direction back and forth at a frequency twice as high as the electromagnetic field frequency.

It seems to me like we need a nonlinearity (at least 2nd order) in order for the Poynting vector average to be different from zero.

Or we need a thermodynamic loss that will produce an energy flux preferentially in one direction
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kdhilliard on 05/24/2015 01:55 AM
This is a supposed quote from Roger Shawyer that I have copy/pasted.

Quote
What the EmDrive thruster does is to produce a force, which we call the thrust, in one direction. This is a force that you can measure. If you put your hand against the end plate that's producing the thrust you'll feel it pushing against you. And, as with all machines that follow Newton's principles, it will therefore accelerate in the opposite direction. So this is not a reactionless thruster, because those things just don't exist outside of science fiction, but it is a propellantless thruster.

It's a little confusing, ...

The quote is from 0:33 of EmDrive Presentation by Roger Shawyer Part 1 of 3 (https://www.youtube.com/watch?v=GGTjy6atKMs), and it's not a little confusing; it's a lot confusing.

I'm pretty sure he is not saying that he has actually felt the thrust with his hand from any of his exiting drives, but instead that were you to build a model with higher thrust you could feel it.  In other words, he is arguing that it is real, not imaginary.

Beyond that, confusion lies.  His published theory only deals with radiation pressure imbalance between the inner surfaces of the two end plates, and the resulting net force on the cavity toward the large end plate.  But instead of allowing it to accelerate big end first, he invokes the powers of the phrase "Conservation of Momentum" to declare that this force, which he has already described as a net force on the cavity, is now somehow a thrust which invokes a reaction force on the cavity causing it to accelerate in the opposite direction.

I'm very reluctant to believe that he would mangle the simple mechanics problem this way without a deeper theory, but I've not found any other explanation.

~Kirk
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 02:01 AM


OK, they get some very interesting, non-intuitive solutions to Maxwell's equations: nondiffracting spatially accelerating solutions, with a Poynting vector that displays a turn of more than 90 degrees. 

Let's say that this would involve an acceleration of the EM Drive when the Poynting vector >0

But then when the Poynting vector < 0 shouldn't the acceleration be in the opposite direction?

And aren't we back to the same situation we are with standing waves in a cavity? : even with standing waves we have a non-zero Poynting vector, the problem is that it keeps switching direction back and forth at a frequency twice as high as the electromagnetic field frequency.

It seems to me like we need a nonlinearity (at least 2nd order) in order for the Poynting vector average to be different from zero.

Or we need a thermodynamic loss that will produce an energy flux preferentially in one direction

Dropping the wall (ie letting it propagate) turns out to be the same as replacing w/ a dielectric resonator.  That, of course, radiates.  It "looks-like" the frustum resonator might radiate in a preferred and mode-dependent direction w/ or w/o the Poynting vector integrating to zero over the complete sphere (after all, antennas do it)

The thermodynamic argument also seems to have asymmetrical promise, what with the up-conversion to ambient and the hot end of the cavity (wish we had that for no dielectric)

I was just thinking that the dielectric resonator could not beat the photon rocket, but that is not true, at that instant the PQ is that of the metallic resonator.  The PQ of the dielectric resonator is much lower due to radiation, but that radiation is frustrated in the metallic resonator.  Remember we are talking static force in this example, no work required.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 02:09 AM
...
Dropping the wall (ie letting it propagate) turns out to be the same as replacing w/ a dielectric resonator.  That, of course, radiates.  It "looks-like" the frustum resonator might radiate in a preferred and mode-dependent direction w/ or w/o the Poynting vector integrating to zero over the complete sphere (after all, antennas do it)
...
would the preferred direction of radiation occur from the Small End directed towards the Big End ?

and if so, why would this be more effective than an open waveguide?

is it because of the Q factor ?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 02:12 AM
See Edit above

Got to work out the preferred direction

OK, yes the preferred direction is from the Small End directed towards the Big End at least from impedance considerations.  Still don't know if the integrated vector is zero as a dielectric cavity radiates in all directions  (some modes have no radiation exactly on the axis, etc) but it looks to be non-zero so far.

Still doesn't show the momentum balance, we are looking at a differential radiation as it goes to zero.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/24/2015 02:49 AM
Ok - I posted this image back on page 42 of thread one. That's about 400 pages back.
http://forum.nasaspaceflight.com/index.php?topic=29276.msg1259471#msg1259471 (http://forum.nasaspaceflight.com/index.php?topic=29276.msg1259471#msg1259471)
But now we know that "something" carrying energy and momentum can change direction without an externally applied force. That something being the light beams discussed in the paper referenced above. Doesn't that mean that by replacing the electrons in my attached drawing with photons, and the driving field with resonate
RF, that we have a mechanism to cause unbalanced forces on the ends of the cavity?

If someone can figure out how these RF beams could maintain resonance then we're home free.

When the beam bounces off the wall, or glances off the base, if the force (Poynting vector) reverses direction then wouldn't the RF beam retrace it's path in reverse? That allows resonance and we are all very familiar with the relationship of thrust to Q, but wouldn't this mechanism give a maximum upper limit of 1Q as apposed to 2Q as the force equation multiplier factor? Unless it turns through a full 90 degrees +, but to much of that would have the radiation going in circles and never hitting anything.

Added: As for the needed nonlinearity, it is the curving path of the radiation.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zaphod_vi on 05/24/2015 02:50 AM
Ah, kdhilliard, i think i might have stolen the quote you typed out. However, this is speculation.

Quote
I'm pretty sure he is not saying that he has actually felt the thrust with his hand from any of his exiting drives, but instead that were you to build a model with higher thrust you could feel it

From the video you could take it either way. Either he has, or you would, feel a force. What is odd though is how do you get from a reaction-less drive that operates by bouncing microwaves around in a cavity, to something that behaves more like a traditional rocket. How do you make that leap. Perhaps Shawyer found the rocket like behaviour when he built his prototype, has mashed the two together because he is not quite sure what is going on, and has been hand-waving ever since.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 02:53 AM
Tossing Poynting vectors around begs the question of how sustained thrust at a level approximately Q times that of an equally-powered photon rocket could possibly obtain.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/24/2015 02:58 AM
Ah, kdhilliard, i think i might have stolen the quote you typed out. However, this is speculation.

Quote
I'm pretty sure he is not saying that he has actually felt the thrust with his hand from any of his exiting drives, but instead that were you to build a model with higher thrust you could feel it

From the video you could take it either way. Either he has, or you would, feel a force. What is odd though is how do you get from a reaction-less drive that operates by bouncing microwaves around in a cavity, to something that behaves more like a traditional rocket. How do you make that leap. Perhaps Shawyer found the rocket like behaviour when he built his prototype, has mashed the two together because he is not quite sure what is going on, and has been hand-waving ever since.

Point of terminology - As Shawyer points out, this is not a reactionless drive, rather a propellant less drive.

Paraphrasing Newton's third law, Action = Reaction. Let's don't break that law along with all the others. If reaction = zero, then Action = zero and zero doesn't show on most force measuring devices that I know of.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 03:06 AM

Added: As for the needed nonlinearity, it is the curving path of the radiation.

I think that's probably the result of a non-linearity.  But we have the differential heating of the end walls ?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/24/2015 03:23 AM

Added: As for the needed nonlinearity, it is the curving path of the radiation.

I think that's probably the result of a non-linearity.  But we have the differential heating of the end walls ?

Yes, I was thinking about that, and the heating pattern is clearly the same as the claimed mode, per Dr. Rodal's calculation and images. But recall that the thrust is very low in the analyzed case, meaning that the RF was turning only a small amount. So is the heating pattern exactly the same, or are the hot spots moved toward the edge by a small amount?

The force on the big end would be something like
BigEndForce = SmallEndForce * (1 - cos(incident angle))
and if we assume a uniform rate of "turn" from the end of the dielectric to the big end, then the distance between the point of impact for a linear RF beam and a curving RF beam would be some integral of curve geometry that I don't have off the top of my head. This distance might or might not show on close examination of the thermal images and prediction theory. It's not likely to be obvious because ... well, just because.

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 03:29 AM

Added: As for the needed nonlinearity, it is the curving path of the radiation.

I think that's probably the result of a non-linearity.  But we have the differential heating of the end walls ?

Yes, I was thinking about that, and the heating pattern is clearly the same as the claimed mode, per Dr. Rodal's calculation and images. But recall that the thrust is very low in the analyzed case, meaning that the RF was turning only a small amount. So is the heating pattern exactly the same, or are the hot spots moved toward the edge by a small amount?

The force on the big end would be something like
BigEndForce = SmallEndForce * (1 - cos(incident angle))
and if we assume a uniform rate of "turn" from the end of the dielectric to the big end, then the distance between the point of impact for a linear RF beam and a curving RF beam would be some integral of curve geometry that I don't have off the top of my head. This distance might or might not show on close examination of the thermal images and prediction theory. It's not likely to be obvious because ... well, just because.

...because the beam image breaks down at wavelengths of the order of the cavity dimensions.  Makes the calculations a bear.  You have to think in terms of distortion of the wave functions instead (makes my head ache)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 03:36 AM
Tossing Poynting vectors around begs the question of how sustained thrust at a level approximately Q times that of an equally-powered photon rocket could possibly obtain.

You only have to prove it instantaneously.  Then it will hold in the frame of reference of the cavity due to GR.  Inertial frames won't do it, they aren't accelerating.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/24/2015 03:47 AM
Now that you bring it up, I'm getting a head ache! And yes, the beam is supposed to be near cut-off, but at the small end, it's OK at the big end, isn't it? The cavity does resonate.

Continuing my simple minded geometric exercise for a curving beam - The dielectric messes up the simplicity of the calculations, but assuming that the RF radiation internal to the cavity imparts a plane wave force on the inside face of the dielectric, F = P*Q/c; Power, Quality factor over speed of light, then the thrust measured would be  - cos(incident angle))*P*Q/c so what was thrust in terms of P*Q/c ? I don't recall the details of the experiment for which the heating patterns were imaged.

And that doesn't seem right. I need to nail down just what angle I'm referring to and that means "stop posting on the fly and use a pencil and paper" until I can define my geometry, at least.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 04:08 AM
http://arxiv.org/abs/0912.1031v1
Feigel says you can get thrust from the vacuum.

http://science.slashdot.org/story/09/12/11/149220/How-To-Build-a-Quantum-Propulsion-Machine
http://www.technologyreview.com/view/416614/a-blueprint-for-a-quantum-propulsion-machine/
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 04:23 AM
Tossing Poynting vectors around begs the question of how sustained thrust at a level approximately Q times that of an equally-powered photon rocket could possibly obtain.

It can't be sustained. It would violate CoE, which is where Shawyer seems to make an error IMO. There has to be a duty cycle involved, where for some length of time Q is charging and a shorter length of time (Much shorter) it is discharged. F = dp/dt  It could never "sustain" thrust (output power) at a level greater than the input power. It can be pulsed to get a particular delta-v however.



Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 04:54 AM
Tossing Poynting vectors around begs the question of how sustained thrust at a level approximately Q times that of an equally-powered photon rocket could possibly obtain.

You only have to prove it instantaneously.  Then it will hold in the frame of reference of the cavity due to GR.  Inertial frames won't do it, they aren't accelerating.

I doubt that. There is an accelerating reference frame of the photons relative to the frustum. There is no accelerating reference frame outside the frustum to propel it, and there is nothing "known" coupling the photons to the quantum vacuum. 

You can have a system whose NET momentum is 0, but the instantaneous momentum is not 0. For example, photons bouncing between two mirrors, the photons have an instantaneous momentum, but the NET of the system is 0.

Now, say there are a large number of photons bouncing between 2 mirrors. Considering only their momentum, if we introduce an asymmetry in attenuation and remove the input power at time t=0. Then, at some a later time t >> 0, the instantaneous momentum of the photons will be 0, but the NET momentum will depend on how many photons were absorbed in either direction. If the attenuation factor is skewed 80% in one direction over the other, then 80% of the photon's momentum will be absorbed in "that" direction. The instantaneous force will depend on how quickly they can be absorbed, dp/dt. It can never exceed the impulse of a photon rocket of output P*Q.

That's my theory, without the math. I need to show how the momentum is coupled from the field to the frustum asymmetrically, but I'm still learning about microwaves, design factors, components, etc... :)

Todd



Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 04:59 AM
Two errors there. First, momentum is conserved at all times in all sensible reference frames for a system comprising a photon bouncing between two mirrors. There is no "borrowing from The Cosmic Badger" going on. Secondly, please don't try and use "the reference frame of a photon", accelerated or otherwise. It's a semantic null statement to put things in that frame of reference. It's also another of Shawyer's conceptual errors.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 05:26 AM
To Iulian and other EM Drive replicators.

To test the linearity of your balance system use 2 coins of equal mass.

Put one coin on top of the centre of the frustum. Null the scale. Remove the coin and note weight reduction. Repeat 5 times and calc average.

Next put one coin on top of the centre of the frustum. Null the scale. Add one coin on top of the 1st and note weight increase. Repeat 5 times and calc average.

You now know how your balance system reports equal weight gain and loss. You can then use the measured factors to adjust the weight changes produced by your EM Drive in either orientation.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 05:37 AM
The other way to put it - we can actually set up a situation where radiation pressure upon the big end is greater than that upon the little end. In space, put a flashlight inside the cavity, pointed upon the big end (which is not perfectly reflective). The radiation pressure upon the big end will be greater than that upon the small end, and the cavity will accelerate big end forward.

(The flashlight, if unsupported, will move in the opposite direction, like a photon rocket, but it could in principle be held in place, e.g. using magnetic levitation)

The flashlight is inside the cavity & will move to the small end, balancing the forces.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 05:40 AM
http://arxiv.org/abs/0912.1031v1
Feigel says you can get thrust from the vacuum.

http://science.slashdot.org/story/09/12/11/149220/How-To-Build-a-Quantum-Propulsion-Machine
http://www.technologyreview.com/view/416614/a-blueprint-for-a-quantum-propulsion-machine/

This is not a theory, it's not even a well thought out hypothesis. First, he has to show what the ground state of these nanoparticles will be, as that is a state where they are in equilibrium with the QV. Then, he has to show there is a state of higher energy that can be pumped by the QV, and re-emitted to do real "work" for propulsion.  Right now, it's conjecture without a lot of explanation.

In a ferroelectric magnet there are domains where electrons have their spins aligned in a particular direction to create a stable magnetic field. The spin of the electron is in its quantum ground state, and spin is intrinsically an interaction between the electron and the QV. If the random spin-flips of electrons can be detected in either direction, then that is extracting energy from the QV.

Likewise, the electromagnetic ZPF is simply the 0 Temperature limit of Planck's blackbody temperature spectrum. If the temperature environment of the magnet is increased, the probability of spin-flips to a higher energy state becomes more likely. The symmetry is broken and can be detected as -dB/dt = curl(E). This can be used to extract electrical energy from the thermal input.

Todd


Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 05:51 AM
Finally completed a simple UI.

One thing to add is the ability to enter the small plate diameter - and switch between small plate diameter or design factor and have the other parameter computed and displayed.

Also a toggle for a small end cylinder. :)

Now to start messing with modes.

I prefer this better than a spreadsheet.  I wrote an Excel like spreadsheet years ago and even with the knowledge I have about them find them constricting.

The cutoff and guide wavelengths are different for TE and TM modes and what m,n values you use. This affects Df.

I adopted my spreadsheet to handle both TE01 and TM01 modes so a 1 cell binary change flips between them.

Length is then determined by numerically intergating 1,000 diameter changes between the end plates and working out the averaged guide wavelength to give 1/2 wave resonance. Then the driving Rf can be a harmonic of the averaged guide wavelength. Length is then adjusted so the external Rf harmonic is the same as the selected Rf wavelength.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 05:59 AM
Two errors there. First, momentum is conserved at all times in all sensible reference frames for a system comprising a photon bouncing between two mirrors. There is no "borrowing from The Cosmic Badger" going on. Secondly, please don't try and use "the reference frame of a photon", accelerated or otherwise. It's a semantic null statement to put things in that frame of reference. It's also another of Shawyer's conceptual errors.

Just to be clear about errors.

Do you believe that Shawyer and the Chinese have made errors in measured thrust in their test devices and there is really no thrust?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zen-in on 05/24/2015 06:01 AM
...

In a ferroelectric magnet there are domains where electrons have their spins aligned in a particular direction to create a stable magnetic field. The spin of the electron is in its quantum ground state, and spin is intrinsically an interaction between the electron and the QV. If the random spin-flips of electrons can be detected in either direction, then that is extracting energy from the QV.

Likewise, the electromagnetic ZPF is simply the 0 Temperature limit of Planck's blackbody temperature spectrum. If the temperature environment of the magnet is increased, the probability of spin-flips to a higher energy state becomes more likely. The symmetry is broken and can be detected as -dB/dt = curl(E). This can be used to extract electrical energy from the thermal input.

Todd

That's a very good equivalence.   Momentum can't be removed from an isolated magnetic field that is at it's lowest energy level and momentum can't be removed from the QV.  It's the same analogy stated a while ago of the bank that floats your account by $100 and won't allow you to draw on that $100.  If any of that was true the universe would be very different and we would probably not be here.

http://math.ucr.edu/home/baez/vacuum.html
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 06:07 AM
Two errors there. First, momentum is conserved at all times in all sensible reference frames for a system comprising a photon bouncing between two mirrors. There is no "borrowing from The Cosmic Badger" going on. Secondly, please don't try and use "the reference frame of a photon", accelerated or otherwise. It's a semantic null statement to put things in that frame of reference. It's also another of Shawyer's conceptual errors.

Okay, my example of mirrors is a bad one. Attenuation is a Lorentz force acting in the frustum that is asymmetrical. It has a unity power factor, and does more work in one direction than it does in the other direction.  Such that given N photons of momentum p0, the work they do as a percentage of thrust left, thrust right or generate heat, is not divided equally.

I did not imply an absolute reference frame, I said "relative". Relative to the frustum, the photons have wavelength A and the small end and wavelength B and the big end. This is by definition an accelerated reference frame between the field and the frustum. The only way to know it's accelerating is by the relative value of the wavelengths.




Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 06:10 AM
Two errors there. First, momentum is conserved at all times in all sensible reference frames for a system comprising a photon bouncing between two mirrors. There is no "borrowing from The Cosmic Badger" going on. Secondly, please don't try and use "the reference frame of a photon", accelerated or otherwise. It's a semantic null statement to put things in that frame of reference. It's also another of Shawyer's conceptual errors.

Just to be clear about errors.

Do you believe that Shawyer and the Chinese have made errors in measured thrust in their test devices and there is really no thrust?
I can understand your curiosity about what all the other pollsters believe, when you yourself are the sole occupant of one of the offered categories.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: RotoSequence on 05/24/2015 08:28 AM
I can understand your curiosity about what all the other pollsters believe, when you yourself are the sole occupant of one of the offered categories.

I think we should avoid getting personal and stick to the science. It seems that we've been drifting off track as of late. There are only a handful of completely honest and truthful statements we can make about EM drive at this time, and most of them involve explaining how and why the existing body of work is not friendly to thrust giving results. Not to discredit hard work and theory development, either by the great scientists who laid the foundations of modern physics, or the participants of the EM drive debate on either side of the fence, but failure to explain the thrust-positive results with analysis is not the same thing as nullifying the experiment's signal. Mathematical models and theories must play a secondary role to the apparatuses.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/24/2015 10:05 AM
What really bothers me in the new Shawyer video are the projections for the future.
Sadly, they kinda eat away his credibility..

Unless he can really show off by standing on a floating platform, powered by his supercooled EMdrive, I'm not prepared to "believe" him because he said so...
I have serious doubts on the needed scalability of the effect (IF it is real) due to the increased thermal effects it will cause.
Assuming there is indeed a measurable force (we're still not 100% sure, although there are intriguing results that point in that direction) it is far from certain that it will ever produce to projected "tons of thrust".

I think one of the first things to test AFTER it has been proven the device works (we're still not past that stage), is to test out whether or not an increased Q has a positive effect on the output forces. It will make all the difference whether we'll have "floating cars" or just micro-thrusters for satellites/solar probes.

With only a few hundred grams of thrust, our lifestyle will not change, but space exploration might...

I was hoping for an explanation on how the thrust force is generated, yet the vagueness of his answer left me perplexed. There is no real argumentation on how CoM is established, except for the confirmation it does.. But, sorry to say, words are easy and cheap...

Also very confusing on having it compare to a rocket engine, saying it isn't a rocket engine, yet use action-reaction to explain the thrust, which is in essence how a rocket engine works... there is an uncomfortable mixing of systems/concepts there. It just isn't a satisfactory explanation for me.

How hard can it be to really show off some of his older outdated test rigs in action? just to convince a larger audience, now his "invention" got the spotlights? Why would you limit yourself to gestures and words only? It's a flawed marketing strategy, certainly when you had such a hard time to convince the scientific community for almost a decade...

Sigh.. kinda disappointing... :'(

ps.
It is strange he almost never looks straight to the interviewer or the camera...feels more like a internal monologue then a communication to persuade others...Needs some media training, for sure.. :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/24/2015 11:10 AM
This may sound harsh but he often seems his own worst enemy when it comes to promoting it.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 11:40 AM
He's a diffident Englishman, an engineer. That's how we speak. We are not trying to sell you toothpaste with lashings of false sincerity and dazzling false smiles. It's a cultural thing.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: CW on 05/24/2015 11:41 AM

(...)

ps.
It is strange he almost never looks straight to the interviewer or the camera...feels more like a internal monologue then a communication to persuade others...Needs some media training, for sure.. :)

When I watched the interview, his constant averting his eyes from the interviewer or camera evoked an impression towards me, as a neutral spectator, that he was literally trying to completely escape the subject at hand. I didn't like that at all. Also, quickly diverting the focus towards applications just increased the feeling of something fishy going on. It left me with a feeling of a marketing man saying 'Yes, our rainbows have a bigger pot of gold at their end. It's a 2nd generation gold pot to boot!' .

I think it is very easy to convince the public that Mr. Shawyer's devices in fact do what he claims: Make a demonstration! We don't need your second generation thrusters that are said to work wonders (IIRC 30kN/kW). A couple Newton per kW, that clearly and visibly accelerate a compact test article for some time and in a useful manner, is all that any critic of your devices needs to shut up, Mr. Shawyer. Is it so hard to do? Really?? And please don't start possibly claiming that as per contract with XYZ you cannot reveal such a demonstration. Such a claim, if made, would maybe impress a hamster, but not human adult scientist-level minds. It is not us, who have to convince ourselves, that your device works as claimed. It is your task to convince us by unambiguous demonstration, that it works as claimed.. .
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/24/2015 11:43 AM
He's a diffident Englishman, an engineer. That's how we speak. We are not trying to sell you toothpaste with lashings of false sincerity and dazzling false smiles. It's a cultural thing.

Here it is not a matter on how you sell a product. We are in need of a serious verification of the effect to ascertain it is real. NASA took the step in the right direction but further independent repetitions are strongly needed.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 12:08 PM
Well, you are absolutely right. I was responding to the critique of the body language of course.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kdhilliard on 05/24/2015 12:30 PM
I'm pretty sure he is not saying that he has actually felt the thrust with his hand from any of his exiting drives, but instead that were you to build a model with higher thrust you could feel it

From the video you could take it either way. Either he has, or you would, feel a force. What is odd though is how do you get from a reaction-less drive that operates by bouncing microwaves around in a cavity, to something that behaves more like a traditional rocket. How do you make that leap. Perhaps Shawyer found the rocket like behaviour when he built his prototype, has mashed the two together because he is not quite sure what is going on, and has been hand-waving ever since.

Point of terminology - As Shawyer points out, this is not a reactionless drive, rather a propellant less drive.

Paraphrasing Newton's third law, Action = Reaction. Let's don't break that law along with all the others. If reaction = zero, then Action = zero and zero doesn't show on most force measuring devices that I know of.

Zaphod: Yes, his words could be taken either way, but taking everything as a whole I'm confident he did not meant that he (or anyone else) has actually felt this trust from an existing EmDrive.  Otherwise he wouldn't need the elaborate test rigs to demonstrate that he had created something novel.

Aero: Yes, Shawyer do claim that it isn't reactionless and that it obeys Newton's laws, but simply claiming so is not enough when the theory he describes doesn't obey these laws.  He's trying to have it both ways.

Law 3 (action vs. reaction) concerns the interaction of two bodies.  In the case of the EmDrive the bodies are the cavity and the photons which are reflecting back and forth inside it.  Every time a photon is reflected off an end plate, it exerts a force against the end plate and the end plate exerts an equal and opposite force against it.  Shawyer claims that there is a net imbalance of forces in the cavity (contrary to most everyone else's application of Maxwell's laws), but that's fine.  He already has had his action and reaction.  Invoking the third law a second time to declare a new reaction force when there are no new additional bodies interacting the the cavity just doesn't make any sense.

He is welcome to claim that he has invented a repulsor drive which can repel your hand when held in close proximity to an end plate or hover some distance over the ground via some perhaps unexplained interaction with the Earth, but that is not what he has done.  He claims to offer a complete fundamental theory behind the operation of the EmDrive, but this theory is not self-consistent.  What he describes does not obey Newton's laws, no matter how much he says to the contrary.

This isn't much different from how Shawyer states that the device obeys Conservation of Energy because the specific thrust declines with acceleration along the thrust vector such that (T/P) < 1/v, meaning that the power consumed is always larger than the work done T v < P.  But this is not enough because CoE is invariant across all inertial reference frames and Shawyer's construction is not.  If a system obeys CoM, then if it obeys CoE in any one frame it obeys CoE in all frames, but Shawyer's system violates CoM so CoE will be violated in all but one frame.  Shawyer conveniently constructs it so that CoE holds in the reference frame from which the cavity starts accelerating from v=0.

~Kirk
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 12:33 PM
He's a diffident Englishman, an engineer. That's how we speak. We are not trying to sell you toothpaste with lashings of false sincerity and dazzling false smiles. It's a cultural thing.
perhaps not a good idea to generalize in the manner of speaking, particularly when it comes to the reluctance to make eye contact, etc., that maybe individual traits...I wonder what it would be like to listen to famous British engineers like James Watt, George and Robert Stephenson, Charles Babbage, Oliver Heaviside, Sir Frank Whittle, and Sir Christopher Cockerell to name a few... Too bad that we don't have videos of Heaviside as I think he would have been a very interesting one to hear.   Maybe there is some film of Frank Whittle around.
(http://upload.wikimedia.org/wikipedia/commons/thumb/9/95/Oheaviside.jpg/220px-Oheaviside.jpg) (http://upload.wikimedia.org/wikipedia/commons/thumb/d/df/Frank_Whittle_CH_011867.jpg/250px-Frank_Whittle_CH_011867.jpg)

Here is one Brit with great penetrating eyes narrating looking at you right in your eyes  and cadence in his voice (@ 1:50) what it was like to work with Whittle

https://www.youtube.com/watch?v=R69ELBnPdTw
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/24/2015 01:08 PM
He's a diffident Englishman, an engineer. That's how we speak. We are not trying to sell you toothpaste with lashings of false sincerity and dazzling false smiles. It's a cultural thing.

I'm not expecting toothpaste or white teethed, tanned faced,  ear to ear smiles... TBH, that would be even less productive then what it is now.

If you've seen some of the interviews with Edward Witten, on string theory, you can clearly see he's not skilled in media training either. That In contrast fe, with Michio Kaku, who's very skilled in using media.
Yet, I'm by far more captivated by E.Witten's interview(s) because it feels so much more authentic and has so much more substantial content.

but, to put things in the correct perspective, it is not my intention to play on his personality. Everybody has his sets of skills and weak points. I do not have anything personal against R.Shawyer. On the contrary. It's just I see it as a missed opportunity : If you know you're not very well in explaining with words, you simply need to show it. Sadly, he did neither...

There would be absolutely no shame into simply saying that he doesn't really know how it works. But evoking theories that can be easily shredded by theoretical physicists does not help his case and that's something, even as an engineer, he should realize.

I doubt it is a pure cultural thing, more of an individual attitude, as i know plenty of engineers that are reasonable and passionate debaters...
however, I used to have a prof in philosophy that had the same characteristics : talking for more then an hour, with his eyes closed and not looking at his audience...     
It's....bizarre...gives you an odd feeling...

I just can not hide my disappointment on the interview.. sorry for that...
With all the raging pro/contra debates i was expecting more for him... my fault probably..
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/24/2015 01:39 PM
Concerning the 3rd presentation video.
https://www.youtube.com/watch?v=l2dwC5Am42Q (https://www.youtube.com/watch?v=l2dwC5Am42Q)

At 19:23 timeframe, a road map for the EMdrive development is shown.

Does any one have a more readable version of it?
With this low resolution, it's just impossible to make anything out of it...
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/24/2015 01:54 PM
It would be better if he had just said sorry I don't really know how it works.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 02:02 PM
Besides the previously discussed facts that Shawyer's theory implies:

1) The Design Factor is calculated as if the EM Drive instead of being a single truncated conical cavity, it is composed of two disjointed separate waveguides, one waveguide having the cut-off frequency of the Big End and the other waveguide having the cut-off frequency of the Small End.

2) Mass of waveguide associated with the Small End is positive, normal mass

3) Mass of waveguide associated with the Big End is negative, exotic mass

4) Total mass of EM Drive cavity is zero.



We have another exotic thing going on when we calculate the Work.  Let's remember from our first course in Physics that the Work of a force is the product of the force vector and the displacement:

Work = Force * displacement

ForceDirection (+) & DisplacementDirection (+)   then Work (+)
ForceDirection (-) & DisplacementDirection (-)   then Work (+)

ForceDirection (+) & DisplacementDirection (-)   then Work (-)
ForceDirection (-) & DisplacementDirection (+)   then Work (-)



the usual case: POSITIVE WORK

When a force acts on a moving body and the direction of the force and the direction of the displacement coincide, then the transfer of energy from the body which exerts the force to the body which is moved is positive. 

A positive value of the Work corresponds to the transmission of energy from the acting body to the body which is moved.  This is the usual case in the overwhelming number of physical cases: the stretching a spring under a tensile force, the compressing of a spring under a compressive force , the displacement of a weight sliding with friction on a surface under the action of a force, etc.



the unusual case: NEGATIVE WORK

When the directions of the force and of the displacement are opposite then conversely, the energy is transmitted from the body which is moved, to the body exerting the force.  In this case, the Work of the force is negative.

Please observe that what Shawyer's theory proposes is that the Thrust Force (directed towards the Big End) is in the opposite direction to the movement of the EM Drive (which is described as taking place towards the Small End).  Hence Shawyer's theory is describing negative Work being done by the EM Drive when it moves towards the Small End.

(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=776944;image)

5) Shawyer's theory (since Shawyer's "Thrust force" exerted by the  microwave photons is in the opposite direction to the movement of the cavity) implies that energy is being transmitted from the copper cavity (the body being moved) to the photons in the cavity (which are exerting the Thrust Force). 

This is the direct opposite of what most people have been discussing in this thread (envisioning the photon's energy as being transmitted to the copper cavity).  Shawyer's theory implies the complete opposite: that energy from the copper cavity is transmitted to the photons  inside the cavity.


Shawyer theory:

motion of Metal Cavity  <====> opposite direction to Thrust force exerted by microwave photons

hence: Negative Work being done

Energy from Metal Cavity (being moved) ==> is transmitted to ==> microwave photons inside cavity (exerting force)



Note: Shawyer's analogy to a rocket is non-viable because a rocket has variable mass , it is the propellant exiting the rocket (like a bullet exiting a gun results in the gun's recoil force), the variable mass of the rocket, that is responsible for a rocket's acceleration.  The EM Drive is a closed cavity and is described by Shawyer as propellant-less with nothing exiting the EM Drive.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/24/2015 02:20 PM
I'm going out on a limb here and I'm going to try to keep it simple as we have many readers that get lost in heavy equations (me too) and collage phd physics. I've been reading so many papers these last few weeks and watching youtube videos trying to get up to speed and polish up an education that is 40 something years old and it's daunting.

Our universe's laws of CoE and CoM, quarks, gluons and gravity... etc, etc. all are ordered, they are clean and fit like a beautiful picture of how our universe works. We're even unraveling what happens around a black hole and even leading to wonderful ideas of what happens in one. The reason all the theories work is because they lay their foundations in solid harmonic (working together) coupled, fundamental forces. I feel comfort that the world is ordered and locked together and things work the way they are supposed to. That's the engineer in me.

I'll tell you where I'm coming from and where I'm going with this thought. I read this weeks ago shortly after I joined this group and it will not go away. I keep coming back to this perception I have of how this self assembled universe works and the one thing that is outside of it all.
Wikipedia~ Our universe started from a dense soup of quark gluon mix and self assembled the only way it could according to those basic forces. The electromagnetic, strong, and weak interactions associate with elementary particles, whose behaviors are modeled in quantum mechanics (QM). For predictive success with QM's probabilistic outcomes, particle physics conventionally models QM events across a field set to special relativity, altogether relativistic quantum field theory (QFT).[4] Force particles, called gauge bosons—force carriers or messenger particles of underlying fields—interact with matter particles, called fermions. Everyday matter is atoms, composed of three fermion types: up-quarks and down-quarks constituting, as well as electrons orbiting, the atom's nucleus. Atoms interact, form molecules, and manifest further properties through electromagnetic interactions among their electrons absorbing and emitting photons, the electromagnetic field's force carrier, which if unimpeded traverse potentially infinite distance. Electromagnetism's QFT is quantum electrodynamics (QED).~
That's beautiful (Shell)

The one "force" that ignored all this mix of neatly assembled pieces and parts and the fundamental forces had to play its game was and is space time.

Spacetime is the one force that can pretty much violate it all and if you remember it's the one thing they measured with the laser through the cavity that seemed to change. By invoking a field of electromagnetic harmonics (TM212 or one like it) that creates a bubble, a null, a void, a hollowed out area within the EM cavity do we start to see a manipulation of space time and space time can violate CoE and CoM like it did in the beginning with the great expansion.

It fits and as strange as it sounds when all else is eliminated and believe me great thinkers and beautiful minds have beat this can and kicked it up down and around and I've read most. Wonderfully the one explanation that is left and it's likely to be the one... spacetime.

Thanks all and question it, pull it out and kick it around like a EM can.
Shell
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 02:23 PM
Tossing Poynting vectors around begs the question of how sustained thrust at a level approximately Q times that of an equally-powered photon rocket could possibly obtain.

You only have to prove it instantaneously.  Then it will hold in the frame of reference of the cavity due to GR.  Inertial frames won't do it, they aren't accelerating.

I think I can state this differently;

All you need for a mathematical "proof" of a thought experiment in this case is to show that a finite force remains in the limit as the work done by the cavity motion goes to zero in some inertial frame. (ie the cavity is accelerating)

"showing it" is the interesting part....
 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zaphod_vi on 05/24/2015 03:12 PM
Quote
Note: Shawyer's analogy to a rocket is non-viable because a rocket has variable mass , it is the propellant exiting the rocket (like a bullet exiting a gun results in the gun's recoil force), the variable mass of the rocket, that is responsible for a rocket's acceleration.  The EM Drive is a closed cavity and is described by Shawyer as propellant-less with nothing exiting the EM Drive.

Alternatively, a rocket throws momentum out of its back end. Perhaps this is what Shawyer means when he talks about thrust. If the net force from the microwaves on the cavity is towards the small end, then the cavity must accelerate towards the small end. However being in violation of CoM there must be momentum ejected in the opposite direction, ergo Shawyers thrust. This would then act as a pushing force in the opposite direction. Quite what the ejected momentum consists of is perhaps another matter.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 03:16 PM
[...]

The cutoff and guide wavelengths are different for TE and TM modes and what m,n values you use. This affects Df.

I adopted my spreadsheet to handle both TE01 and TM01 modes so a 1 cell binary change flips between them.

Length is then determined by numerically intergating 1,000 diameter changes between the end plates and working out the averaged guide wavelength to give 1/2 wave resonance. Then the driving Rf can be a harmonic of the averaged guide wavelength. Length is then adjusted so the external Rf harmonic is the same as the selected Rf wavelength.

Is there any particular combination of length, radii and frequency, that would make the energy difference between the TM01 and TM11, or other mode very large? If there is a way to maximize this gap in energy, it will maximize the energy stored in TM01, I think...
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/24/2015 03:22 PM

Spacetime is the one force that can pretty much violate it all and if you remember it's the one thing they measured with the laser through the cavity that seemed to change. By invoking a field of electromagnetic harmonics (TM212 or one like it) that creates a bubble, a null, a void, a hollowed out area within the EM cavity do we start to see a manipulation of space time and space time can violate CoE and CoM like it did in the beginning with the great expansion.


Until proven otherwise I'll point to Lisa Randall's gravity brane and the hypothetical finite length 4th spacial dimension.  Inflate that dimension using RF energy and the strength of gravity is diminished.  The Universe itself inflated  3 spatial dimensions in the inflationary period, so there is a mechanism.

Upcoming experiments at CERN this summer are looking to confirm/disprove predictions from her theory. As I understand these are the first predictions to come from string theory that are testable.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 03:27 PM

Spacetime is the one force that can pretty much violate it all and if you remember it's the one thing they measured with the laser through the cavity that seemed to change. By invoking a field of electromagnetic harmonics (TM212 or one like it) that creates a bubble, a null, a void, a hollowed out area within the EM cavity do we start to see a manipulation of space time and space time can violate CoE and CoM like it did in the beginning with the great expansion.


Until proven otherwise I'll point to Lisa Randall's gravity brane and the hypothetical 4th spacial dimension.  Inflate that dimension using RF energy and the strength of gravity is diminished.  The Universe itself inflated  3 spatial dimensions in the inflationary period, so there is a mechanism.

Upcoming experiments at CERN this summer are looking to confirm/disprove predictions from her theory. As I understand these are the first predictions to come from string theory that are testable.

Yes, that could give a gradient and the cavity could "fall" toward the small end.

All you need is for the cosmological constant to be a function of the radiation field strength (like in the early universe ?)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 03:29 PM
https://www.youtube.com/watch?v=ypMKjxUe0BE

Streamed live on Apr 25, 2013
Special guest theorists Lisa Randall from Harvard University and Raman Sundrum from University of Maryland, who join CERN physicists to look at how the LHC experiments are investigating extra dimensions.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 03:57 PM
[...]

The cutoff and guide wavelengths are different for TE and TM modes and what m,n values you use. This affects Df.

I adopted my spreadsheet to handle both TE01 and TM01 modes so a 1 cell binary change flips between them.

Length is then determined by numerically intergating 1,000 diameter changes between the end plates and working out the averaged guide wavelength to give 1/2 wave resonance. Then the driving Rf can be a harmonic of the averaged guide wavelength. Length is then adjusted so the external Rf harmonic is the same as the selected Rf wavelength.

Is there any particular combination of length, radii and frequency, that would make the energy difference between the TM01 and TM11, or other mode very large? If there is a way to maximize this gap in energy, it will maximize the energy stored in TM01, I think...

Shawyer says you only need to excite the frustum in TM mode and have end plate to end plate resonance at the effective 1/2 guide wavelength and the external Rf to be a harmonic of that effective guide wavelength.

End result is all 4 physical dimensions of the frustum, big & small diameter, end plate spacing and external Rf all affect each other. To get good thrust at a set frequency needs the 3 physical dimensions to be manulipulated in an interactive process that properly models how they interact.

I also feel doing a frequency sweep to look for resonance mush be done slowly as it takes time for a high Q frustum to react to the external Rf and fully fill the cavity. Sweep too fast and you may miss the high Q sweet spots.

The sweep must excite the cavity in TM mode. Putting a stub antenna through the frustum side wall will not, as far as I understand the process, excite TM mode. It will just excite TE mode. It seems you need to put the probe in the middle of one end to excite TM mode. But I'm not yet a microwave engineer, so there may be other ways to excite TM mode.

Any comments on how to excite TM mode, in a frustum, with a coax feed would be most welcome.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 04:13 PM
Two errors there. First, momentum is conserved at all times in all sensible reference frames for a system comprising a photon bouncing between two mirrors. There is no "borrowing from The Cosmic Badger" going on. Secondly, please don't try and use "the reference frame of a photon", accelerated or otherwise. It's a semantic null statement to put things in that frame of reference. It's also another of Shawyer's conceptual errors.

Just to be clear about errors.

Do you believe that Shawyer and the Chinese have made errors in measured thrust in their test devices and there is really no thrust?
I can understand your curiosity about what all the other pollsters believe, when you yourself are the sole occupant of one of the offered categories.

So why avoid answering my question? Btw I'm not the sole occupant.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kdhilliard on 05/24/2015 04:18 PM
Some people are comfortable with minor violations of Conservation of Momentum or Conservation of Energy as long as it doesn't occur in such as way as to allow for Perpetual Motion Devices or Free Energy Machines.  I feel that it is worth a few words to address Shawyer's attempt at Conservation of Energy.

Shawyer's FAQ (http://emdrive.com/faq.html) #18:
Quote
The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.

The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.

Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.

Without this decrease in specific thrust the situation is obvious.  Were you to install a 30 kN/kW EmDrive on an airplane and use it to accelerate the plane to its cruising speed of 100 m/s, it would then be doing 3 MW of mechanical work for every 1 kW of power it consumes.  Shawyer addresses this by limiting the specific thrust to the reciprocal of the velocity, T/P < 1/v.  This means that the work is restricted to be less than the power consumed, T v < P.

Nowhere in his Theory Paper (http://www.emdrive.com/theorypaper9-4.pdf) does he explicitly state T/P < 1/v, but that is what you get by taking equation (16), combining it with his definition of thrust, and taking the limit on Q.  He also gives an example on pg. 8-9 where an EmDrive which has accelerated to 3 km/s is limited to a specific thrust of 333 mN/kW.  (Note that 333 mN/kW = 0.333 (kg m / s^2) / (10^3 kg m^2 / s^3) = 1 / (3 km/s) = 1/v.)

However this is not an emergent property of his theory, but is instead explicitly added on pg. 7-8 where he declares that the output power from the device which is transferred into the device's kinetic energy is equal to the change of the kinetic energy of the device (as measured in the reference frame from which the drive first started accelerating from v=0), and thus P_k = M v a = v T.  With total power equal to the sum P_k and the electrical losses P_e, we automatically have P < v T.

But just declaring that energy is conserved because it was constructed that way (in one reference frame) is not sufficient.  Conservation of energy is supposed to be invariant across inertial reference frames.  If momentum is conserved, then if energy is conserved in any one inertial reference frame it is conserved in all inertial reference frames.  But momentum is not conserved here, so even though CoE is declared to hold in one reference frame it will be violated in others.

Consider a 3 kN/kW EmDrive constructed and energized for the first time all while flying in an airplane traveling at its steady cruise velocity of 100 m/s (194 kts).  As far as the drive is concerned, it is at much at rest as its counterpart which was constructed and and first energized in a ground-based laboratory, but when energized the airborne drive will be doing 3 MW or work for every 1 kW of power it consumes, and this is work which could be harvested via air turbines extended from the plane.


Question:  Do other theories for these sorts of drives include this reduction in specific thrust as a function of velocity obtained via acceleration of the drive along the thrust vector?  Dr. Rodal, for the  feature article (http://www.nasaspaceflight.com/2015/04/evaluating-nasas-futuristic-em-drive/) you reported on Dr. Whites simulation, "The computer code also shows that the efficiency, as measured by the thrust to input power ratio, decreases at input powers exceeding 50 kiloWatts."  I assume that his theory would be properly invariant and not suffer reduction of specific thrust as a function of velocity.

~Kirk
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 04:24 PM

[...]


I also feel doing a frequency sweep to look for resonance mush be done slowly as it takes time for a high Q frustum to react to the external Rf and fully fill the cavity. Sweep too fast and you may miss the high Q sweet spots.

The sweep must excite the cavity in TM mode. Putting a stub antenna through the frustum side wall will not, as far as I understand the process, excite TM mode. It will just excite TE mode. It seems you need to put the probe in the middle of one end to excite TM mode. But I'm not yet a microwave engineer, so there may be other ways to excite TM mode.

Any comments on how to excite TM mode, in a frustum, with a coax feed would be most welcome.

You are correct, to excite TM01 modes you should insert your stub-antenna in the middle of one end, preferably the small end. Then do a slow sweep like you said, to fine tune the resonant frequency. IMO, it probably doesn't matter if the stub antenna extended all the way through the axis of the frustum and attached to the big end, because that end should be a Null in the p-mode, TM01p anyway.

I'm currently working on analyzing this design, without the connection. So far, what I know is the capacitance is maximized at the small end, and the inductance is maximized at the big end. The magnetic Lorentz force, qv x B is not symmetrical between the walls and the antenna, because B is zero on the axis of the antenna, due to the symmetry of the frustum. However, calculating qE between them is more difficult, since relative phase is critical to the direction of the NET force.  It appears to work like a current transformer with a DC offset, due to an unbalanced resistive load on each half-cycle. Eventually it equalizes, but it can be pulsed to gain thrust as it decays.

Todd
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 04:31 PM
...Dr. Rodal, for the  feature article (http://www.nasaspaceflight.com/2015/04/evaluating-nasas-futuristic-em-drive/) you reported on Dr. Whites simulation, "The computer code also shows that the efficiency, as measured by the thrust to input power ratio, decreases at input powers exceeding 50 kiloWatts."  I assume that his theory would be properly invariant and not suffer reduction of specific thrust as a function of velocity.

~Kirk
I would not assume that, as any such assumption, as you so eloquently showed above for Shawyer's formulation is done at the peril of the person doing the assuming.

Dr. White's comments are paraphrased from his papers in a number of AIAA publications, WarpTech and DeltaMass and Frobnicat (for the longest time), among others, have discussed this. A valiant attempt was made by the person working on the EM Drive wiki, to condense the discussion on energy conservation and its attendant paradox:  http://emdrive.echothis.com/Generic_EM_Drive_Information

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 04:39 PM
...You are correct, to excite TM01 modes you should insert your stub-antenna in the middle of one end, preferably the small end. Then do a slow sweep like you said, to fine tune the resonant frequency. IMO, it probably doesn't matter if the stub antenna extended all the way through the axis of the frustum and attached to the big end, because that end should be a Null in the p-mode, TM01p anyway. ...
Todd, given the excitation frequencies and geometrical dimensions of the EM Drives being considered I presume you are discussing exciting some high mode TM01p with a higher p greater than 0.

Such a (high p) mode will be very difficult to single out and excite by itself because they lie next to several other modes having m>0 that have a variation of the electromagnetic field in the azimuthal variation.

Recall the experience of NASA Eagleworks that had issues of exciting TE012 (which initially gave a high thrust/InputPower) and had to stay with TM212, now for practically a year.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/24/2015 04:49 PM
https://www.youtube.com/watch?v=ypMKjxUe0BE

Streamed live on Apr 25, 2013
Special guest theorists Lisa Randall from Harvard University and Raman Sundrum from University of Maryland, who join CERN physicists to look at how the LHC experiments are investigating extra dimensions.

Great video.  It touches on so many topics that get discussed here on this forum.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 04:55 PM
Quote
Note: Shawyer's analogy to a rocket is non-viable because a rocket has variable mass , it is the propellant exiting the rocket (like a bullet exiting a gun results in the gun's recoil force), the variable mass of the rocket, that is responsible for a rocket's acceleration.  The EM Drive is a closed cavity and is described by Shawyer as propellant-less with nothing exiting the EM Drive.

Alternatively, a rocket throws momentum out of its back end. Perhaps this is what Shawyer means when he talks about thrust. If the net force from the microwaves on the cavity is towards the small end, then the cavity must accelerate towards the small end. However being in violation of CoM there must be momentum ejected in the opposite direction, ergo Shawyers thrust. This would then act as a pushing force in the opposite direction. Quite what the ejected momentum consists of is perhaps another matter.

Since the year 1900 by Lebedev (see:  http://web.ihep.su/dbserv/compas/src/lebedev01/eng.pdf ), experiments have been conducted, confirming that Maxwell was correct that the radiation pressure of photons against a surface push the surface in the same direction as the force, such that positive work is performed. 

This (Maxwell's theory and the experiments that have verified it)  is in sharp contrast with Shawyer's theory claiming that the Thrust pressure of photons towards the Big Diameter results in motion of the EM Drive in the opposite direction, towards the Small Diameter.  (This results, as I have shown, in the curious behavior that the Work being done is negative, according to Shawyer's theory)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 05:06 PM
Quote from: WarpTech
You are correct, to excite TM01 modes you should insert your stub-antenna in the middle of one end, preferably the small end. Then do a slow sweep like you said, to fine tune the resonant frequency. IMO, it probably doesn't matter if the stub antenna extended all the way through the axis of the frustum and attached to the big end, because that end should be a Null in the p-mode, TM01p anyway.

As per the attachment as well. Can't excite TM mode in a resonate cylinderical cavity via side wall mounted antenna.

Question: Did EWs test a non dielectric frustum, excited in TM mode via an antenna inserted in the middle of either end?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/24/2015 05:08 PM
https://www.youtube.com/watch?v=ypMKjxUe0BE

Streamed live on Apr 25, 2013
Special guest theorists Lisa Randall from Harvard University and Raman Sundrum from University of Maryland, who join CERN physicists to look at how the LHC experiments are investigating extra dimensions.
I thoroughly enjoyed this, Thanks Dr. Rodal!!! 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Mulletron on 05/24/2015 05:20 PM
You know, we have a fan club now; where the million views came from. People who are counting on us to do the right thing, every time; without question. We're at the forefront. No different than those before us who dared to go against the grain. If we are selfless, and put good science on the table...maybe things will progress.

https://www.reddit.com/r/EmDrive/

History will judge us someday.

This is step one. Our first real chance to get it right. If we fail......
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 05:49 PM
Interesting.

Chinese theory claims thrust directs to the small / minor end plate and the H field force is many times greater than the E field force on the end plates.

Thus they excite their frustum in TE011 mode.

Would appreciate the theory guys doing as much due diligence on the attached Chinese paper as has been done on Shawyers papers.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: apoc2021 on 05/24/2015 06:04 PM
The one "force" that ignored all this mix of neatly assembled pieces and parts and the fundamental forces had to play its game was and is space time.
...
By invoking a field of electromagnetic harmonics (TM212 or one like it) that creates a bubble, a null, a void, a hollowed out area within the EM cavity do we start to see a manipulation of space time and space time can violate CoE and CoM like it did in the beginning with the great expansion.
...
Wonderfully the one explanation that is left and it's likely to be the one... spacetime.

Shell, thank you for this comment - this is an elegant view, and it reminds me of Einstein79's comments in thread 2. The sense I have gotten is that we aren't thinking big enough, as everything is always in motion including space itself even when we are at an apparent standstill. This IMHO causes our conventional concepts such as thrust and acceleration to fall short of requirements needed to explain what we are observing.

In the end I think we'll have come to realize that creating EM fields in a particular way alters spacetime in a particular way. For example the low power tests at EW compress spacetime ever so slightly and for us the observable effect most closely resembles thrust. Perhaps once refined the distances become arbitrary.

I think this is what EW was getting at - EM drive thrust, "warp drive"... Simply variations on a theme.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/24/2015 06:09 PM
After going back and forth on the presence of rubber o-rings I've decided that they are needed for pressurization of the cavity and keeping two dissimilar metals apart for terrestrial applications might be important as well.  I looked at adding a choke ditch with an o-ring and decided that wasn't necessary with the wavelengths we are working with - though the guys building the 25GHz version might need this.

So in my construction I'm shortening the cone length by 2x the thickness of the o-ring. With screws applying 1000 lbs/inch the rubber will compress so I'm looking for equations on the amount of compression that will occur and compensate accordingly.

I'm not a waveguide engineer - and as TheTraveler likes to say 'yet' - so this is based on what I have read so far - if anyone can point me to other references to refine the design I would be delighted.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 06:10 PM
Interesting.

Chinese theory claims thrust directs to the small / minor end plate and the H field force is many times greater than the E field force on the end plates.

Thus they excite their frustum in TE011 mode.

Would appreciate the theory guys doing as much due diligence on the attached Chinese paper as has been done on Shawyers papers.
1) Please note that the screenshot you quoted deals entirely (100%) with their numerical predictions and it has no comparison whatsoever (in that screenshot) to experimental measurements.  Please let us know if you see a comparison of their theoretical predictions to their actual experimental measurements (I haven't read those papers in a long time and I don't recall)

2) Please note that the Finite Element software package they are using (which now belongs to ANSYS) is entirely based on the solution to the linear Maxwell differential equations and it is based entirely on the same numerical formulation used by COMSOL FEA and also the same equations that I solved exactly with my exact solution that you were previously criticizing.  Prof. Yang's predictions for the TEmnp and TMmnp modes are entirely based on standing waves.  They are not at all based on waveguides as you previously thought.  Prof. Yang's prediction of thrust is entirely uncoupled from her TEmnp and TMmnp mode predictions.

3) Notice that Prof. Yang, unlike Shawyer, refers to cavity modes (TEmnp and TMmnp) instead of open waveguide modes TMmn.

4) As Prof. Yang details in her paper, her "thrust" prediction is made a posteriori based on the numerical solution of Maxwell's equations as standing waves.  She performs an a posteriori calculation of the FEM classical solution, ignoring the pressure on the side walls.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Mulletron on 05/24/2015 06:20 PM
Interesting.

Chinese theory claims thrust directs to the small / minor end plate and the H field force is many times greater than the E field force on the end plates.

Thus they excite their frustum in TE011 mode.

Would appreciate the theory guys doing as much due diligence on the attached Chinese paper as has been done on Shawyers papers.

Would appreciate a look at this lecture chap 7.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 06:21 PM
...Great video.  It touches on so many topics that get discussed here on this forum.

...I thoroughly enjoyed this, Thanks Dr. Rodal!!!
As PhaseShift said it is interesting how this video deals with a number of topics we have been discussing.  For example, the question is asked (by somebody at CERN) to Sundrum as to whether there is a relation of the extra dimension(s) to the Quantum Vacuum virtual particles.  The answer is that this is unknown.  They are using Heisenberg's uncertainty principle as a given.  Sundrum emphasizes the fact that we can borrow much larger amounts of energy than we own (no need of collateral) but that you have to pay it back in an extremely small amount of time.  They are using this ability to borrow larger energy from the QV in their experiments to explore energy being lost in the extra dimension(s). Thus, the issue with Dr. White's proposal is the need to payback, in a very small amount of time, any energy you may borrow (the QV being immutable and non-degradable over longer periods of time).  Essentially, Dr. White's proposal is that one can default on the mortgage  :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 06:21 PM
Quote from: Rodal
----

Her conclusion and final paper attached.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 06:34 PM
Quote from: Rodal
----

Her conclusion and final paper attached.

Very interesting.  Thus we see here that Prof. Yang, far from imitating Shawyer, states a completely different conclusion: that the "measured net EM thrust" is directed towards the small end (towards the "minor end plate"), (the complete opposite of what Shawyer states).  She also states that this thrust direction (towards the small end) agrees with her theoretical prediction of thrust direction.

AND her theory predicts the thrust level per power input.  All without needing new  physics.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 06:42 PM
Quote from: Rodal
----

Her conclusion and final paper attached.

Very interesting.  Thus we see here that Prof. Yang, far from imitating Shawyer, states a completely different conclusion: that the "measured net EM thrust" is directed towards the small end (towards the "minor end plate"), (the complete opposite of what Shawyer states).  She also states that this thrust direction (towards the small end) agrees with her theoretical prediction of thrust direction.
When you say "toward the small end plate", do you mean from the outside or the inside? That's the ambiguity with using that sort of nomenclature.

Once again, I recommend using "small end forward" etc. as the least ambiguous designator of the direction of the resultant thrust vector - the one which produces acceleration.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/24/2015 06:44 PM
...Great video.  It touches on so many topics that get discussed here on this forum.

...I thoroughly enjoyed this, Thanks Dr. Rodal!!!
As PhaseShift said it is interesting how this video deals with a number of topics we have been discussing.  For example, the question is asked (by somebody at CERN) to Sundrum as to whether there is a relation of the extra dimension(s) to the Quantum Vacuum virtual particles.  The answer is that this is unknown.  They are using Heisenberg's uncertainty principle as a given.  Sundrum emphasizes the fact that we can borrow much larger amounts of energy than we own (no need of collateral) but that you have to pay it back in an extremely small amount of time.  They are using this ability to borrow larger energy from the QV in their experiments to explore energy being lost in the extra dimension(s). Thus, the issue with Dr. White's proposal is the need to payback, in a very small amount of time, any energy you may borrow (the QV being immutable and non-degradable over longer periods of time).  Essentially, Dr. White's proposal is that one can default on the mortgage  :)

As I understand it the amount of time that a virtual particle can exist is inversely proportional to the energy borrowed. Thus low debt particles have more time to travel than large debt particles.  So around whole quanta particles there is a fuzzy cloud of 'particles'/'waves' - low debt particles are farther away then high debt particles.  This can be and has been measured - we do interact with the virtual quantum vacuum.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 06:50 PM
...
When you say "toward the small end plate", do you mean from the outside or the inside? That's the ambiguity with using that sort of nomenclature.

Once again, I recommend using "small end forward" etc. as the least ambiguous designator of the direction of the resultant thrust vector - the one which produces acceleration.
what matters is what she means:  her words: "net EM ... directs towards the minor end plate". The microwave EM is inside not outside, hence no ambiguity
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/24/2015 06:51 PM
http://www.gizmag.com/scientists-create-real-protons-from-virtual-ones/20689/

Huh, that's interesting.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Blaine on 05/24/2015 07:04 PM
This is a conversation on reedit about using two different metals for a DIY experiment for EM Drive.  I butted in but the headline and description read as fallows:

The EmDrive has been ridiculed by other scientists because Sawyer does not take into account of the sidewalls into his calculations. They say that the microwaves also push down on the sidewalls so no net positive force in any direction is created.

However, I think I have an idea that may improve the net force of the EmDrive. Microwaves bounce around inside the EmDrive before that energy is converted to heat. What if the sidewalls were made of a metal that converted the energy to heat more rapidly than the flat-ends? For example, the sidewalls could be made off copper and the flatends could be made of tin. Tin heats up more slowly than copper so the microwaves would bounce off the tin generating a force. When the microwaves hit the copper sidewalls some of that force is converted to heat quicker than the tin, and therefore there will less force on the sidewalls as compared to the tin.

So, if the EmDrive is multicompound with tin ends and copper sides then a bigger force will be generated



You have a few misconceptions about what is going on. The argument about 'pushing' on the walls involves momentum exchange which should be conserved so there is no way net force should be apparent from the outside. This is what the controversy is about.

The EM waves don't really 'bounce around'. If the chamber is resonating the waves are standing waves and would appear to not move if you could see them.

The heat comes from the resistive loss (low Q) of the chamber. This somewhat different from the momentum exchange and has to do with energy loss rather than momentum. The difference is on the quantum level, but they are two different things. In fact reducing the heat by making the chamber super conducting is expected to increase the thrust, which is the opposite of your idea. This is because we're talking about two different things (friction or heat vs. momentum).

Force from thermal expansion is very minimal and is internal to the junction between the two metals, there should really be no apparent external force or movement due to thermal heating or differencing in heating coefficients.
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[–]BlaineMiller 1 point 4 minutes ago*

Ah, but look at it from a chemistry point of view. Couldn't the different materials on the side wall also produce microwave radiation? Because if what if we were talking about thermal agitation of two different metals?

Thermal agitation is one source of microwaves at the heart of atoms and molecules. Any action that these atoms have at higher temperatures above absolute zero can cause them to absorb and emit radiation, including microwaves. Maybe the thermal motion of the atoms in the copper is somehow absorbing enough radiation to make it possible to ignore that there would be zero net force. In other words, the sides of this asymmetrical cavity would not feel any force. All the extra radiation would be inside the copper atoms because of thermal motion of atoms because of thermal agitation and microwave absorption properties of the end metal.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 07:07 PM
http://www.gizmag.com/scientists-create-real-protons-from-virtual-ones/20689/

Huh, that's interesting.
People are playing around with "electron mirrors" these days with a view to reflecting gammas. The inertia of such a contraption is exceedingly low and, being charged, is highly amenable to being vibrated. I wonder if there's a way to do a direct dynamic Casimir experiment with this technique.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/24/2015 07:15 PM
...Great video.  It touches on so many topics that get discussed here on this forum.

...I thoroughly enjoyed this, Thanks Dr. Rodal!!!
As PhaseShift said it is interesting how this video deals with a number of topics we have been discussing.  For example, the question is asked (by somebody at CERN) to Sundrum as to whether there is a relation of the extra dimension(s) to the Quantum Vacuum virtual particles.  The answer is that this is unknown.  They are using Heisenberg's uncertainty principle as a given.  Sundrum emphasizes the fact that we can borrow much larger amounts of energy than we own (no need of collateral) but that you have to pay it back in an extremely small amount of time.  They are using this ability to borrow larger energy from the QV in their experiments to explore energy being lost in the extra dimension(s). Thus, the issue with Dr. White's proposal is the need to payback, in a very small amount of time, any energy you may borrow (the QV being immutable and non-degradable over longer periods of time).  Essentially, Dr. White's proposal is that one can default on the mortgage  :)
Ahhh the Quantum Vacuum, the QV. If there wasn't so much evidence that it exists as appearing and disappearing particles and forces from somewhere out of the planck levels of space and possible links into another dimension of space time, I'd think QV is a Genie in the bottle.
Reading about the QV http://en.wikipedia.org/wiki/Vacuum_state
What is that time period I need to "give it back"? a femtosecond, 1 week, a couple years, the forecast age of the universe? I'm not sure if it is a set time as we see it. And what if I warped, just a little and just enough spacetime with an EM field, would that have an effect of the borrowed time and during that time I had it couldn't I just strip of a little something extra before I gave it back?
My head is feeling a little mushy and I think I need some hot tub time with something cold.
To all, thanks for putting up with me and my crackpot ideas of our world.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 07:18 PM
Quote from: Rodal
----

Her conclusion and final paper attached.

Very interesting.  Thus we see here that Prof. Yang, far from imitating Shawyer, states a completely different conclusion: that the "measured net EM thrust" is directed towards the small end (towards the "minor end plate"), (the complete opposite of what Shawyer states).  She also states that this thrust direction (towards the small end) agrees with her theoretical prediction of thrust direction.

AND her theory predicts the thrust level per power input.  All without needing new  physics.

"A hollow microwave resonant cavity is evolved from the RLC loop.[15] In the cavity, the power damped by the wall skin effect, Pr, stored in electric and magnetic fields, Pe, Ph, correspond to the power consumed by the resistance and stored in the capacitance and the inductance of the RLC loop, respectively. Therefore the parameters of the cavity also have |Pe|=|Ph|= Qcavity*Pr= Qcavity*Pinput, where Qcavity and Pinput are the cavity quality factor and the power consumed by the microwave resonant cavity, respectively..."

I'd say, she nailed it! And she's better at the math than I am.

Todd
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 07:26 PM
If Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:

1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks
2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.

No new physics?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 07:31 PM
...Would appreciate a look at this lecture chap 7.

Quote from: Germain Rousseaux
The ‘‘Galilean’’ equations used by van Tiggelen et al.
[1] in bianisotropic media as well as Feigel [2] in dielectric
media to prove the existence of the so-called ‘‘Feigel effect’’
are a mixing of these two separate Galilean transformation
laws. Hence, I suggest that the effects predicted by
van Tiggelen et al. and Feigel are not observable within the
realm of Galilean Physics as they are based on wrong hypotheses.
...’ Now, to be honest, the
authors try in their reply to formulate a Lorentz-covariant
theory in order to show that ‘‘zero-point momentum is
allowed in a fully Lorentz-invariant model.’’ I would leave
this point to others for discussion but stand still on the
impossibility to describe the Feigel–van Tiggelen effect in
a Galilean way.

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.100.248901
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 07:36 PM
http://www.gizmag.com/scientists-create-real-protons-from-virtual-ones/20689/

Huh, that's interesting.
People are playing around with "electron mirrors" these days with a view to reflecting gammas. The inertia of such a contraption is exceedingly low and, being charged, is highly amenable to being vibrated. I wonder if there's a way to do a direct dynamic Casimir experiment with this technique.
Another approach is to use a nanotube fixed at one end only. The free end will achieve pretty high velocities. But the news is not good, even from state-of-the-art, which is 10 nm length and 100 GHz frequency for goodness sake. That's still only 6 Km/s at the tip.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 07:39 PM
...
"A hollow microwave resonant cavity is evolved from the RLC loop.[15] In the cavity, the power damped by the wall skin effect, Pr, stored in electric and magnetic fields, Pe, Ph, correspond to the power consumed by the resistance and stored in the capacitance and the inductance of the RLC loop, respectively. Therefore the parameters of the cavity also have |Pe|=|Ph|= Qcavity*Pr= Qcavity*Pinput, where Qcavity and Pinput are the cavity quality factor and the power consumed by the microwave resonant cavity, respectively..."

I'd say, she nailed it! And she's better at the math than I am.

Todd

Yeap, it's kind of funny that we are looking at Prof. Yang's this late in the game.  After all she achieved much higher reported thrust than Shawyer. I think the reason is that Yang does not give the dimensions of her EM Drive.  We naturally concentrated on NASA first.  Also Shawyer because he gave some dimensions (the big diameter of the Exp and the Demo).

It is evident that Prof. Yang's theory is not Shawyer's theory.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 07:48 PM
...
"A hollow microwave resonant cavity is evolved from the RLC loop.[15] In the cavity, the power damped by the wall skin effect, Pr, stored in electric and magnetic fields, Pe, Ph, correspond to the power consumed by the resistance and stored in the capacitance and the inductance of the RLC loop, respectively. Therefore the parameters of the cavity also have |Pe|=|Ph|= Qcavity*Pr= Qcavity*Pinput, where Qcavity and Pinput are the cavity quality factor and the power consumed by the microwave resonant cavity, respectively..."

I'd say, she nailed it! And she's better at the math than I am.

Todd

Yeap, it's kind of funny that we are looking at Prof. Yang's this late in the game.  After all she achieved much higher reported thrust than Shawyer. I think the reason is that Yang does not give the dimensions of her EM Drive.  We naturally concentrated on NASA first.  Also Shawyer because he gave some dimensions (the big diameter of the Exp and the Demo).

It is evident that Prof. Yang's theory is not Shawyer's theory.

That is not new news.  Shawyer has stated the Chinese developed another approach to his many times. End result of both approaches is the same level of measured versus predicted thrust.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 07:53 PM
...That is not new news.  Shawyer has stated the Chinese developed another approach to his many times. End result of both approaches is the same level of measured versus predicted thrust.
Well,let's forget all the differences between Yang's approach from Shawyer's, using waveguide modes like TM01 (she is using FEA instead based on standing waves), cut off length and other Shawyer stuff, and the fact that she predicts the force in the complete opposite direction as to Shawyer.  But let's forget about that.  How do you know that "both approaches is the same level of measured versus predicted thrust." ?

Do you have dimensions for Prof Yang's EM Drive so that we can assess such a prediction?

Also I don't understand the point you make about predictions.  Prof Yang uses standard FEM analysis based on Maxwell's equations, identical to COMSOL formulation to predict the modes.  Completely different from Shawyer
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: dustinthewind on 05/24/2015 07:57 PM
... Wonderfully the one explanation that is left and it's likely to be the one... spacetime.

Thanks all and question it, pull it out and kick it around like a EM can.
Shell

That is the only way at the moment I see how we can violate conservation of momentum with out using propellant is by using information delay over space and time.  Normally the universe appears to conserve these forces (and charge) given enough time.  Once we start modulating information faster than the universe can keep up with it (over space and time) then we might be able to tip the balance so to speak. 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Mulletron on 05/24/2015 08:03 PM
...Would appreciate a look at this lecture chap 7.

Quote from: Germain Rousseaux
The ‘‘Galilean’’ equations used by van Tiggelen et al.
[1] in bianisotropic media as well as Feigel [2] in dielectric
media to prove the existence of the so-called ‘‘Feigel effect’’
are a mixing of these two separate Galilean transformation
laws. Hence, I suggest that the effects predicted by
van Tiggelen et al. and Feigel are not observable within the
realm of Galilean Physics as they are based on wrong hypotheses.
...’ Now, to be honest, the
authors try in their reply to formulate a Lorentz-covariant
theory in order to show that ‘‘zero-point momentum is
allowed in a fully Lorentz-invariant model.’’ I would leave
this point to others for discussion but stand still on the
impossibility to describe the Feigel–van Tiggelen effect in
a Galilean way.

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.100.248901

We all know that Feigel was falsified. What you are quoting is greater than 7 years old and was responded to by another letter * which you conveniently left out. Your amateur attempts at misdirection, rather than academic rebuttal won't go unnoticed. Try harder Doctor. I kindly ask you to excuse yourself from discussion, as you are of no help.

* http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.100.248902

Finally from here:
Quote
Second, the final result
obtained by Feigel for the Casimir momentum density, ∼ ~ R χnr
EMk3dk, seems to lack
a reference frame since this equation is not Lorentz or even Galilean invariant [23].

http://arxiv.org/abs/1404.5990v2

 (free open reference) this is published


Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 08:06 PM
...That is not new news.  Shawyer has stated the Chinese developed another approach to his many times. End result of both approaches is the same level of measured versus predicted thrust.
Well, I will refrain from reengaging on the fact that a short time ago you were stating that Prof Yang was using the same theory as Shawyer, that she was using TM01, cut off length, and the fact that she predicts the force in the complete opposite direction as to Shawyer.  But let's forget about that.  How do you know that "both approaches is the same level of measured versus predicted thrust." ?

Do you have dimensions for Prof Yang's EM Drive so that we can assess such a prediction?

Please don't  put words in my mouth. I never said the Yang & Shawyers theories were the same. I said both theories claimed to be able to predicted the observed thrust. I also stated both theory approaches were different.

How do I know for sure the predicted thrust is the measured thrust? I don't. But then I'm just an engineer that builds stuff on assumption the models I'm using produce close  to reality results. My excel spreadsheet can't yet do that but every day it gets closer to that goal.

You see I'm not really that interested in the theory other than what it teaches me about how the 4 variables interact.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 08:06 PM
This discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.

Let's cut the Gordian Knot!
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 08:11 PM
...
We all know that Feigel was falsified. What you are quoting is greater than 7 years old and was responded to by another letter * which you conveniently left out. Your amateur attempts at misdirection, rather than academic rebuttal won't go unnoticed. Try harder Doctor. I kindly ask you to excuse yourself from discussion, as you are of no help.
...
Wow.  What a kind response to somebody answering your "...Would appreciate a look at this lecture chap 7."
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/24/2015 08:13 PM
This discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.

Let's cut the Gordian Knot!

The test program I  plan to run will remove ALL doubt that the EMDrive generates real propellantless thrust without needing a space test.

One of my goals is to be able to hold the EMDrive & while switching it on and off, to be able to FEEL the thrust.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 08:20 PM
http://www.eagleyard.com/uploads/tx_tdoproductstorage/EYP-TPA-0808-02000-4006-CMT04-0000.pdf

is a nice little asymmetric cavity device just itching to get into space.
But 50 mW in gets you 2 Watts out?
Heh. Forget cavities  8)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 08:21 PM
This discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.

Let's cut the Gordian Knot!

I fully agree.  I think that the space test should be in a controlled course, to also eliminate doubt from anomalies.
Removing doubt is readily achieved by running two identical devices side by side, and only switching on one of them.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: dustinthewind on 05/24/2015 08:22 PM
Quote
Note: Shawyer's analogy to a rocket is non-viable because a rocket has variable mass , it is the propellant exiting the rocket (like a bullet exiting a gun results in the gun's recoil force), the variable mass of the rocket, that is responsible for a rocket's acceleration.  The EM Drive is a closed cavity and is described by Shawyer as propellant-less with nothing exiting the EM Drive.

Alternatively, a rocket throws momentum out of its back end. Perhaps this is what Shawyer means when he talks about thrust. If the net force from the microwaves on the cavity is towards the small end, then the cavity must accelerate towards the small end. However being in violation of CoM there must be momentum ejected in the opposite direction, ergo Shawyers thrust. This would then act as a pushing force in the opposite direction. Quite what the ejected momentum consists of is perhaps another matter.

Since the year 1900 by Lebedev (see:  http://web.ihep.su/dbserv/compas/src/lebedev01/eng.pdf ), experiments have been conducted, confirming that Maxwell was correct that the radiation pressure of photons against a surface push the surface in the same direction as the force , such that positive work is performed. 

This (Maxwell's theory and the experiments that have verified it)  is in sharp contrast with Shawyer's theory claiming that the Thrust pressure of photons towards the Big Diameter results in motion of the EM Drive in the opposite direction, towards the Small Diameter .  (This results, as I have shown, in the curious behavior that the Work being done is negative, according to Shawyer's theory)

What about running the current in the aluminum ring in the picture in reverse of the direction the electric field of light would drive the current.  That would take work to do but wouldn't that in effect be reversing the direction of push to pull? 

optical tweezers also strike me as changing the pressure of light from positive to negative.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 08:25 PM
...
When you say "toward the small end plate", do you mean from the outside or the inside? That's the ambiguity with using that sort of nomenclature.

Once again, I recommend using "small end forward" etc. as the least ambiguous designator of the direction of the resultant thrust vector - the one which produces acceleration.
what matters is what she means:  her words: "net EM ... directs towards the minor end plate". The microwave EM is inside not outside, hence no ambiguity

What she means by "Thrust" is very clear. It is the sum off all the electric and magnetic forces acting the surfaces of the frustum. What Shawyer refers to as thrust is ambiguous, since he says the side walls have no contribution to the forces.

Her use of complex fields incorporates the attenuation factors. With her equations, 12 thru 14, and the graphs in Zeng and Fan, predictions can be extrapolated based on theta. I said I had a lot of reading to do. I wish I had read this one a week ago.

On another note: You might be able to excite a TM01 mode from the side of the frustum using a loop rather than stub. Where the plane of the loop is parallel to the axis of the frustum.

Thanks!
Todd
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: wallofwolfstreet on 05/24/2015 08:31 PM
This discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.

Let's cut the Gordian Knot!

The test program I  plan to run will remove ALL doubt that the EMDrive generates real propellantless thrust without needing a space test.

One of my goals is to be able to hold the EMDrive & while switching it on and off, to be able to FEEL the thrust.

You may have posted it somewhere before Traveller, but I haven't had the chance to read the entirety of threads 1 and 2.  Do you have a general idea of what kind of timeline you are going to be working off of with your test program?  Do you expect to have a build ready in the next two months, with another month or two for testing, or do you expect it take longer?

Just trying to get a sense of experimental development on this device given we can't expect EW results until at least late July.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/24/2015 08:38 PM
This discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.

Before spending the effort and money to send something into space, we should first try to build something here on earth that works beyond reasonable doubt. This means a thrust greater then what the sum of all possible secondary effects might cause. Personally, I think if a device could generate 50 to 100 gf in a prolonged manner, without noticing any jet/exhausts, I'd consider the EMdrive thrust as very, very likely...
Only then additional research, up there (pointing up), in the hard vacuum would make sense...

Until we first get good solid results here on earth, there is really no reason to send it up... You don't want to spend millions to find out you made an error, or that it simply doesn't work...you most definitely want a real space test, for sure, but not yet at this stage...

Let's wait a bit, till TheTravler get's his stuff ready and the guys at Eagleworks get green light to bring us the (good ?) news.  Let's hope P.March has not been permanently muted... :'(
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 08:49 PM
If Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:

1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks
2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.

No new physics?

I choose 1, and Einstein would not shriek. For example. In a gravitational field, if I have 2 identical clocks, held stationary at different altitudes in the field, they do not run at the same speed. How do they know? Because there is a difference in potential energy, i.e. the integrated accelerations along each clocks worldliness are not the same. The resulting "velocity", or in this case, gravitational potential is not the same. When a force F is exerted, and the integral over time results in a velocity v, the refractive index at that potential is not the same as it was in the frame it started from at rest. Regardless if it is an inertial frame when the engine is turned off. You can have 2 inertial frames, no acceleration, that do not have the same relative refractive index. It is referred to as a conformal transformation I believe.

Todd





Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 08:52 PM
...
What she means by "Thrust" is very clear. It is the sum off all the electric and magnetic forces acting the surfaces of the frustum. What Shawyer refers to as thrust is ambiguous, since he says the side walls have no contribution to the forces.

Her use of complex fields incorporates the attenuation factors. With her equations, 12 thru 14, and the graphs in Zeng and Fan, predictions can be extrapolated based on theta. I said I had a lot of reading to do. I wish I had read this one a week ago.

On another note: You might be able to excite a TM01 mode from the side of the frustum using a loop rather than stub. Where the plane of the loop is parallel to the axis of the frustum.

Thanks!
Todd

Notice that Prof. Yang writes Section 3.2 page 9 of the translated paper http://www.emdrive.com/NWPU2010translation.pdf :

Quote from: Yang
Mode TM011 thrusters has the worst performance 

this is diametrically opposite to Shawyer's reported aim at TM01

(Recall that TM010 is an impossible mode for truncated cones because p=0 stands for constant electromagnetic field in the longitudinal direction which is impossible for a truncated cone.  Hence it is not immediately clear to me what degenerate mode of TM011 she is referring to as there are two degenerate TM011 modes in a truncated cone near each other)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: flux_capacitor on 05/24/2015 08:57 PM
...That is not new news.  Shawyer has stated the Chinese developed another approach to his many times. End result of both approaches is the same level of measured versus predicted thrust.
Well,let's forget that a short time ago you were stating that Prof Yang was using the same theory as Shawyer, that she was using waveguide modes like TM01, cut off length and other Shawyer stuff, and the fact that she predicts the force in the complete opposite direction as to Shawyer.  But let's forget about that.  How do you know that "both approaches is the same level of measured versus predicted thrust." ?

Do you have dimensions for Prof Yang's EM Drive so that we can assess such a prediction?

Did you already ask her directly? [email protected]

I found her email in her published papers and on her profile page (http://hangtian.nwpu.edu.cn/info/1549/7982.htm) on the Northwestern Polytechnical University web site.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 09:01 PM
If Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:

1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks
2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.

No new physics?

I choose 1, and Einstein would not shriek. For example. In a gravitational field, if I have 2 identical clocks, held stationary at different altitudes in the field, they do not run at the same speed. How do they know? Because there is a difference in potential energy, i.e. the integrated accelerations along each clocks worldliness are not the same. The resulting "velocity", or in this case, gravitational potential is not the same. When a force F is exerted, and the integral over time results in a velocity v, the refractive index at that potential is not the same as it was in the frame it started from at rest. Regardless if it is an inertial frame when the engine is turned off. You can have 2 inertial frames, no acceleration, that do not have the same relative refractive index. It is referred to as a conformal transformation I believe.

Todd
If you'd be good enough to confine the discussion to a field-free (at least to zeroth and first order) region of space, you will find that you are paying a price to ascribe an absolute value to velocity. As I wrote before, consider this thought experiment:
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1370943#msg1370943

EDIT and here are my two "position posts" rolled into one
http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369875#msg1369875
 

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 09:03 PM
...That is not new news.  Shawyer has stated the Chinese developed another approach to his many times. End result of both approaches is the same level of measured versus predicted thrust.
Well,let's forget that a short time ago you were stating that Prof Yang was using the same theory as Shawyer, that she was using waveguide modes like TM01, cut off length and other Shawyer stuff, and the fact that she predicts the force in the complete opposite direction as to Shawyer.  But let's forget about that.  How do you know that "both approaches is the same level of measured versus predicted thrust." ?

Do you have dimensions for Prof Yang's EM Drive so that we can assess such a prediction?

Did you already ask her directly? [email protected]

I found her email in her published papers and on her profile page (http://hangtian.nwpu.edu.cn/info/1549/7982.htm) on the Northwestern Polytechnical University web site.

No.  I (at least) never contacted her.  Thanks.

First I have to take a very close look at her paper because I just now realized (hat tip to Todd) that she does take into account the pressure in all faces (upon further reading now I realize that it was only early in the paper when she is going over Shawyer's theory that she refers to neglecting the pressure on the side walls.  She does not neglect those pressures), to understand how she approaches the conservation of momentum issues.

It seems to me at first glance that she addresses it by the heat dissipation which gives direction to the Poynting vector.

EDIT: At this point I don't understand how this can result a closed cavity having a performance thousands of time better than a perfect photon rocket.   ???
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 09:10 PM
If Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:

1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks
2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.

No new physics?

I choose 1, and Einstein would not shriek. For example. In a gravitational field, if I have 2 identical clocks, held stationary at different altitudes in the field, they do not run at the same speed. How do they know? Because there is a difference in potential energy, i.e. the integrated accelerations along each clocks worldliness are not the same. The resulting "velocity", or in this case, gravitational potential is not the same. When a force F is exerted, and the integral over time results in a velocity v, the refractive index at that potential is not the same as it was in the frame it started from at rest. Regardless if it is an inertial frame when the engine is turned off. You can have 2 inertial frames, no acceleration, that do not have the same relative refractive index. It is referred to as a conformal transformation I believe.

Todd

It also appears that Prof. Yang solves the CoM puzzle by taking into account dissipation losses, which involves the 2nd law of thermodynamics and hence entropy.

Entropy gives a preferred direction (causality).   
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 09:14 PM
Yang doesn't take the free dynamics bull by the horns.

Also, if she's using heat dissipation as an explanation, how does this system manage  not to be a photon rocket?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/24/2015 09:16 PM
New blog post on this topic from Physics from the Edge.

http://physicsfromtheedge.blogspot.co.uk/2015/05/emdrive-whence-motion.html?m=1
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 09:45 PM
...
On another note: You might be able to excite a TM01 mode from the side of the frustum using a loop rather than stub. Where the plane of the loop is parallel to the axis of the frustum.


Notice that Prof. Yang writes Section 3.2 page 9 of the translated paper http://www.emdrive.com/NWPU2010translation.pdf :

Quote from: Yang
Mode TM011 thrusters has the worst performance 

this is diametrically opposite to Shawyer's reported aim at TM01

(Recall that TM010 is an impossible mode for truncated cones because p=0 stands for constant electromagnetic field in the longitudinal direction which is impossible for a truncated cone.  Hence it is not immediately clear to me what degenerate mode of TM011 she is referring to as there are two degenerate TM011 modes in a truncated cone near each other)

She said; "(2) The calculation of the different modes and different cavity structure, the mode TM012 which has smallest cavity Large-End has the largest thrust, so has the highest quality factor and thrust. Mode TM011 thrusters has the worst performance."

So a narrower cone angle, and a TM012 mode. What's wrong with that? The TM011 mode is not bad, but requires a larger cone, so of course it will be weaker. I actually think this is theoretically correct.

Note, TM010 mode I think would be the case of a DC current carrying wire running down the axis of the frustum. And TE011 would be a solenoid. (Like the primary winding of a transformer perhaps?) 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 09:48 PM
Yang doesn't take the free dynamics bull by the horns.

Also, if she's using heat dissipation as an explanation, how does this system manage  not to be a photon rocket?

Yes, thousands of times better than a perfect photon rocket.  The easy answer is "Q", but Q is the opposite of dissipation.  I think we have to take a look at this in detail.  Already some very interesting things:

1) Yang has the thrust force (from the EM field) directed towards the Small End. This is completely opposite to Shawyer's unorthodox "thrust force".

2) Yang experimentally measured the highest temperature (by far) at the Small End.  (Opposite to NASA, but NASA had a dielectric HDPE at the small end isolating the small end).

3) Effective Q used by Yang in her experiments (calculated the same way as in the West) is significantly lower than Shawyer's Q.

4) Yang writes that Shawyer's preferred mode shape (TM011, notice that TM010 is impossible for a truncated cone) transverse magnetic with m=0, n=1,"has the worst performance" for production of thrust (the complete opposite has been reported for Shawyer in this thread).
(EDIT: but see Todd's note just above this one concerning geometry used in that assessment)

No idea how she can get Force/InputPower thousands of times better than perfect photon rocket.


QUESTION: Has anyone gone over Yang's calculation of the Input Power to make sure she calculates it the same way as in the West ? (I never did)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 10:02 PM
If Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:

1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks
2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.

No new physics?

I choose 1, and Einstein would not shriek. For example. In a gravitational field, if I have 2 identical clocks, held stationary at different altitudes in the field, they do not run at the same speed. How do they know? Because there is a difference in potential energy, i.e. the integrated accelerations along each clocks worldliness are not the same. The resulting "velocity", or in this case, gravitational potential is not the same. When a force F is exerted, and the integral over time results in a velocity v, the refractive index at that potential is not the same as it was in the frame it started from at rest. Regardless if it is an inertial frame when the engine is turned off. You can have 2 inertial frames, no acceleration, that do not have the same relative refractive index. It is referred to as a conformal transformation I believe.

Todd

It also appears that Prof. Yang solves the CoM puzzle by taking into account dissipation losses, which involves the 2nd law of thermodynamics and hence entropy.

Entropy gives a preferred direction (causality).

Exactly right! I was going to mention where she said;

"|Pe|=|Ph|= Qcavity*Pr= Qcavity*Pinput"

Note that if Pr = 0, . i.e, no dissipation losses, then the integrated forces will be zero, because all energy AND EM momentum will be stored in the capacitance and inductance, like a battery. If you could switch ON, Pr at time t=0, then that battery would discharge asymmetrically, into thrust.

It appears however that she is making the same mistake Shawyer makes, in neglecting the duty cycle. The loaded Q must decrease quickly, or else there will be no thrust.
 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Raj2014 on 05/24/2015 10:05 PM
They have tested it in a vacuum. What will they do next with the EM drive? Will they possibly build a spacecraft with the EM drive to be tested in orbit?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: flux_capacitor on 05/24/2015 10:05 PM
1) Yang has the thrust force (from the EM field) directed towards the Small End. This is completely opposite to Shawyer's unorthodox "thrust force".

I'm starting to wonder if Shawyer doesn't use the term "thrust" as something similar to the "thrust the exhaust gas of a rocket would produce if the cavity was, er, a rocket" (i.e. opposite to the direction of movement), and the term "reaction" as the meaning of "direction of the movement of the cavity" relatively to the "virtual" thrust. I'm not sure, since EmDrive does not expel anything. We don't understand what Shawyer tries to explain with his scheme "thrust vs reaction" (CoM evidently, but it is evident only to him).

Everyone else (Eagleworks, NWPU, Cannae LLC, you, me) uses the word "thrust" as the force in the direction of movement, i.e. small end forward.

So if Shawyer use the word "reaction" instead of our thrust, how could we understand each other? And I insist, I'm not even sure what term he chose for the direction of movement. That's so trivially weird :(
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 10:09 PM
If Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:

1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks
2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.

No new physics?

No. 2 is not quite correct since all of the "free energy" schemes have circular terms in the Hamiltonian and only the acceleration to spacial seperation looks that way.  Noether snoozes.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/24/2015 10:09 PM
A few pages back, pg. 4, I commented on the possibility that curving RF beams (see http://physics.technion.ac.il/~msegev/publications/Maxwell_accelerating_beams.pdf (http://physics.technion.ac.il/~msegev/publications/Maxwell_accelerating_beams.pdf))
could be responsible for the thrust. I have calculated how much turn the beams would need in order to provide the measured thrust. These are for older experiments, Eagleworks 50 W experiments reported this year are missing, as are all the Canne thrusters including the superconducting thruster.
                                                  Big end incident angle
    Test Data used                          degrees
Shawyer Experimental                   31.4508375
Shawyer Demonstrator                  16.6880148
Yaun a -                                        -0.139288
Yaun b -                                         3.1903738
 Brady - a                                     62.8096712
 Brady - b                                     77.2015432
 Brady - c                                       58.7399415 This is the 2.6 Watt test.
 Shawyer Flight                             -0.0278019

Here, the incident angle of the RF on the small end is assumed to be 90 degrees giving small end force
Fs = 2*P*Q/c * sin(90)  in accordance with Maxwell's equations for a plane wave. The RF radiation within the cavity is assumed to turn as allowed by the mathematics in the referenced paper:
http://physics.technion.ac.il/~msegev/publications/Maxwell_accelerating_beams.pdf (http://physics.technion.ac.il/~msegev/publications/Maxwell_accelerating_beams.pdf)

The fly in the ointment is the thermal camera images taken at Eagleworks and confirmed mathematically by Dr. Rodal. The images and theory would seem to allow only small turn angles while the test data, applying my theory gives quite large turn angles. Not impossibly large but large enough that the offset of the heating of the big end would likely have been noticed.

So another hopeful theory damaged by real data. Can't I just pick and choose the data I want to use  :'(         


Edit add: I don't know the uncertainty of the measurement data, force, Q and P but it is quite likely large enough to justify reducing the turn angles to less than 90 degrees for the Yaun a -, and Shawyer Flight cases.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 10:21 PM
Yang doesn't take the free dynamics bull by the horns.

Also, if she's using heat dissipation as an explanation, how does this system manage  not to be a photon rocket?

(...)
No idea how she can get Force/InputPower thousands of times better than perfect photon rocket.

(...)

Make Q a cyclic, time dependent, PWM duty cycle controlled function, not a constant!

It charges until it has enough thrust to overcome the resistance of the mass, but once it moves, that energy is dissipated. P drops back to Pin and Q has to build up again. I don't see any other way...



Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 10:21 PM
http://www.eagleyard.com/uploads/tx_tdoproductstorage/EYP-TPA-0808-02000-4006-CMT04-0000.pdf

is a nice little asymmetric cavity device just itching to get into space.
But 50 mW in gets you 2 Watts out?
Heh. Forget cavities  8)

"with proper injection from a seed laser"
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kdhilliard on 05/24/2015 10:33 PM
They have tested it in a vacuum. What will they do next with the EM drive? Will they possibly build a spacecraft with the EM drive to be tested in orbit?

Back in February, Paul March, an engineer at NASA's Eagleworks Lab, reported (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1326608#msg1326608) on their vacuum results -- 50 micro-Newtons forward at 50W, 16 micro-Netwons reverse with a failing RF amp.  These are very small forces, and while they believe that these results are not due to thermal effects (such as imbalance due to thermal expansion), they need to increase the thrust to at least 100 micro-Newtons before trying to replicate the experiment at NASA Glenn Research Center since the lowest force that GRC's thrust stand can measure is about 50 micro-Newtons.  They are also setting up a 1.2kW non-vacuum test (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1366772#msg1366772) from which they hope to have results by July.

Summary: The lab considers the results to be promising, but they are not definitive, and there is a lot more work to do on Earth before testing in orbit.

~Kirk
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 10:43 PM
1) Yang has the thrust force (from the EM field) directed towards the Small End. This is completely opposite to Shawyer's unorthodox "thrust force".

I'm starting to wonder if Shawyer doesn't use the term "thrust" as something similar to the "thrust the exhaust gas of a rocket would produce if the cavity was, er, a rocket" (i.e. opposite to the direction of movement), and the term "reaction" as the meaning of "direction of the movement of the cavity" relatively to the "virtual" thrust. I'm not sure, since EmDrive does not expel anything. We don't understand what Shawyer tries to explain with his scheme "thrust vs reaction" (CoM evidently, but it is evident only to him).

Everyone else (Eagleworks, NWPU, Cannae LLC, you, me) uses the word "thrust" as the force in the direction of movement, i.e. small end forward.

So if Shawyer use the word "reaction" instead of our thrust, how could we understand each other? And I insist, I'm not even sure what term he chose for the direction of movement. That's so trivially weird :(

My understanding so far of what he says is this;

First, refers to "thrust" as the EM field moving backwards, and "reaction" as the frustum moving forwards, toward the small end. His idea of thrust is that when the photons are reflected from the small end, the frustum goes forward, the photons go backwards, and momentum is exchanged on the bounce. When they reach the back wall, the effect is the opposite and now "thrust" is forward and "reaction" is backwards, toward the big end. These two reactions do not add to zero. This is why it is not only confusing to read it, but to understand it. Thrust and reaction are both bi-directional, but their sum is not zero.



Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 10:54 PM
Yang doesn't take the free dynamics bull by the horns.

Also, if she's using heat dissipation as an explanation, how does this system manage  not to be a photon rocket?

(...)
No idea how she can get Force/InputPower thousands of times better than perfect photon rocket.

(...)

Make Q a cyclic, time dependent, PWM duty cycle controlled function, not a constant!

It charges until it has enough thrust to overcome the resistance of the mass, but once it moves, that energy is dissipated. P drops back to Pin and Q has to build up again. I don't see any other way...
Quite frankly, if the thrust measured is to be taken at face value, then it appears to be on order Q*(photon rocket thrust at the same power).  Obviously not sustainable, as you point out. Indeed, to simply be a non-magic photon rocket, the duty cycle has to be 1:1/Q
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 10:56 PM
If Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:

1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks
2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.

No new physics?

No. 2 is not quite correct since all of the "free energy" schemes have circular terms in the Hamiltonian and only the acceleration to spacial seperation looks that way.  Noether snoozes.
Well, in that case I must ask you to go through my equations and to spot the error.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/24/2015 11:01 PM
...Great video.  It touches on so many topics that get discussed here on this forum.

...I thoroughly enjoyed this, Thanks Dr. Rodal!!!
As PhaseShift said it is interesting how this video deals with a number of topics we have been discussing.  For example, the question is asked (by somebody at CERN) to Sundrum as to whether there is a relation of the extra dimension(s) to the Quantum Vacuum virtual particles.  The answer is that this is unknown.  They are using Heisenberg's uncertainty principle as a given.  Sundrum emphasizes the fact that we can borrow much larger amounts of energy than we own (no need of collateral) but that you have to pay it back in an extremely small amount of time.  They are using this ability to borrow larger energy from the QV in their experiments to explore energy being lost in the extra dimension(s). Thus, the issue with Dr. White's proposal is the need to payback, in a very small amount of time, any energy you may borrow (the QV being immutable and non-degradable over longer periods of time).  Essentially, Dr. White's proposal is that one can default on the mortgage  :)
Ahhh the Quantum Vacuum, the QV. If there wasn't so much evidence that it exists as appearing and disappearing particles and forces from somewhere out of the planck levels of space and possible links into another dimension of space time, I'd think QV is a Genie in the bottle.
Reading about the QV http://en.wikipedia.org/wiki/Vacuum_state
What is that time period I need to "give it back"? a femtosecond, 1 week, a couple years, the forecast age of the universe? I'm not sure if it is a set time as we see it. And what if I warped, just a little and just enough spacetime with an EM field, would that have an effect of the borrowed time and during that time I had it couldn't I just strip of a little something extra before I gave it back?
My head is feeling a little mushy and I think I need some hot tub time with something cold.
To all, thanks for putting up with me and my crackpot ideas of our world.
I asked this question here because when I told my grandson who is in first year engineering asked me almost this very same question.  I said virtual particles really don't exist except in calculations and mostly are not or can not be observed in the real world. He sent me this from Wikipedia and said not true. Could anyone help me here to put this into a easier form to understand? Thanks
http://en.wikipedia.org/wiki/Virtual_particle
Manifestations[edit]
There are many observable physical phenomena that arise in interactions involving virtual particles. For bosonic particles that exhibit rest mass when they are free and actual, virtual interactions are characterized by the relatively short range of the force interaction produced by particle exchange.[citation needed] Examples of such short-range interactions are the strong and weak forces, and their associated field bosons. For the gravitational and electromagnetic forces, the zero rest-mass of the associated boson particle permits long-range forces to be mediated by virtual particles. However, in the case of photons, power and information transfer by virtual particles is a relatively short-range phenomenon (existing only within a few wavelengths of the field-disturbance, which carries information or transferred power), as for example seen in the characteristically short range of inductive and capacitative effects in the near field zone of coils and antennas.[citation needed]
Some field interactions which may be seen in terms of virtual particles are:
The Coulomb force (static electric force) between electric charges. It is caused by the exchange of virtual photons. In symmetric 3-dimensional space this exchange results in the inverse square law for electric force. Since the photon has no mass, the coulomb potential has an infinite range.
The magnetic field between magnetic dipoles. It is caused by the exchange of virtual photons. In symmetric 3-dimensional space this exchange results in the inverse cube law for magnetic force. Since the photon has no mass, the magnetic potential has an infinite range.
Electromagnetic induction. This phenomenon transfers energy to and from a magnetic coil via a changing (electro)magnetic field.
The strong nuclear force between quarks is the result of interaction of virtual gluons. The residual of this force outside of quark triplets (neutron and proton) holds neutrons and protons together in nuclei, and is due to virtual mesons such as the pi meson and rho meson.
The weak nuclear force - it is the result of exchange by virtual W and Z bosons.
The spontaneous emission of a photon during the decay of an excited atom or excited nucleus; such a decay is prohibited by ordinary quantum mechanics and requires the quantization of the electromagnetic field for its explanation.
The Casimir effect, where the ground state of the quantized electromagnetic field causes attraction between a pair of electrically neutral metal plates.
The van der Waals force, which is partly due to the Casimir effect between two atoms.
Vacuum polarization, which involves pair production or the decay of the vacuum, which is the spontaneous production of particle-antiparticle pairs (such as electron-positron).
Lamb shift of positions of atomic levels.
Hawking radiation, where the gravitational field is so strong that it causes the spontaneous production of photon pairs (with black body energy distribution) and even of particle pairs.
Much of the so-called near-field of radio antennas, where the magnetic and electric effects of the changing current in the antenna wire and the charge effects of the wire's capacitive charge may be (and usually are) important contributors to the total EM field close to the source, but both of which effects are dipole effects that decay with increasing distance from the antenna much more quickly than do the influence of "conventional" electromagnetic waves that are "far" from the source. ["Far" in terms of ratio of antenna length or diameter, to wavelength]. These far-field waves, for which E is (in the limit of long distance) equal to cB, are composed of actual photons. It should be noted that actual and virtual photons are mixed near an antenna, with the virtual photons responsible only for the "extra" magnetic-inductive and transient electric-dipole effects, which cause any imbalance between E and cB. As distance from the antenna grows, the near-field effects (as dipole fields) die out more quickly, and only the "radiative" effects that are due to actual photons remain as important effects. Although virtual effects extend to infinity, they drop off in field strength as 1/r2 rather than the field of EM waves composed of actual photons, which drop 1/r (the powers, respectively, decrease as 1/r4 and 1/r2). See near and far field for a more detailed discussion. See near field communication for practical communications applications of near fields.
Most of these have analogous effects in solid-state physics; indeed, one can often gain a better intuitive understanding by examining these cases. In semiconductors, the roles of electrons, positrons and photons in field theory are replaced by electrons in the conduction band, holes in the valence band, and phonons or vibrations of the crystal lattice. A virtual particle is in a virtual state where the probability amplitude is not conserved. Examples of macroscopic virtual phonons, photons, and electrons in the case of the tunneling process were presented by Günter Nimtz [9] and Alfons A. Stahlhofen.[10]
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 11:02 PM
...

NOTE: A structural Finite Element solution with a rigid body mode (free to translate in space) is singular, hence the matrix cannot be inverted.  What boundary conditions did she choose? How did she get rid of rigid body modes to get a Stress Tensor solution?    I also have to look at how she dealt with that (CoM)
Of course, the way she deals with this complexity is that she ignores it.  Prof. Yang did not calculate the stresses on a deformable EM Drive.  Yang considered the EM Drive to be an infinitely rigid solid, she did not perform an FEA of the deformation due to thermal strains caused by the dissipation.  This avoids having to deal with a singular matrix and taking out the rigid body modes.

Yang computed the Maxwell Stress tensor components from the electromagnetic field based on a solution of Maxwell's differential equations (taking into account dissipation) for an infinitely rigid EM Drive.   This explains why later she had to perform elaborate experiments by embedding thermocouples in the real, deformable, EM Drive (the first researcher to do so).

Yang's EM Drive must distort under the effect of the high input energy she uses, and this thermal deformation must make the EM Drive detune itself from the high Q resonance: hence her later effort to understand the thermal effects. Of coursse, we don't have her EM Drive dimensions, so we don't know how deformable it is. (The drawings and the fact that she was able to embed thermocouples in the walls make me feel that her EM Drive is much thicker than NASA's).

Also notice that NASA could not get any thrust without a dielectric insert using the same mode shape preferred by Yang: TE012 and that NASA could only perform one test with the dielectric (where they got the highest thrust/InputEnergy of any reported experiment) but they could not reproduce it consistently and they had to switch to TM212.  It looks to me that TE012 must result in thermal deformation of the cavity, particularly with the thinnness of copper used by NASA Eagleworks.  This results in NASA's thin EM Drive detuning itself.  Since NASA was not using a magnetron, NASA has more problems with this TE012 mode since it may result in greater thermal deformation of NASA's EM Drive than the deformation under the highr mode TM212.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/24/2015 11:07 PM

My understanding so far of what he says is this;

First, refers to "thrust" as the EM field moving backwards, and "reaction" as the frustum moving forwards, toward the small end. His idea of thrust is that when the photons are reflected from the small end, the frustum goes forward, the photons go backwards, and momentum is exchanged on the bounce. When they reach the back wall, the effect is the opposite and now "thrust" is forward and "reaction" is backwards, toward the big end. These two reactions do not add to zero. This is why it is not only confusing to read it, but to understand it. Thrust and reaction are both bi-directional, but their sum is not zero.

aahhh... that would make sense...
basically he's describing the radiation pressure on both front and back plate...
http://en.wikipedia.org/wiki/Radiation_pressure#/media/File:Sail-Force1.gif

damn..you really have a gift of writing things out in a clear and layman-understandable way...

but from a radiation pressure point of view, part of the big plate and the totality of the front plate nullify each other, so if there is a difference to be observed, shouldn't it be in the difference between the angled sides and the small left over of (big plate - small plate)?

The fact that the sidewalls are angled give me the impression that electromagnetic waves will bounce more often on the sidewalls of the frustum when going towards the small end, then when going towards the big end.
This is because reflection angles on the sidewalls are steeper when going to the small end, and more shallow going the other direction.

Now... a silly idea/question...

but is the size of a force/momentum truly linear with the angle of incidence?
cause, if a force would be a bit less then linear for a shallow angle, that could account for the residual force towards the small end?
Are there any studies about momentum/force transfer for electromagnetic waves when reflected?

Probably talking nonsense here, but you never know, even a blind man can hit a target.. :-[
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/24/2015 11:11 PM
If Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:

1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks
2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.

No new physics?

No. 2 is not quite correct since all of the "free energy" schemes have circular terms in the Hamiltonian and only the acceleration to spacial seperation looks that way.  Noether snoozes.
Well, in that case I must ask you to go through my equations and to spot the error.

? ? ? http://emdrive.echothis.com/Theory ?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/24/2015 11:15 PM
If Yang "nailed it" with "no new physics", which of Noether or Einstein did she decide to trash? Because you have to choose, and either way, it's new physics. To recap: for the free motion:

1. If P = F v, then magically v is known, which implies a preferred rest frame, and Einstein shrieks
2. If P = F = constant, then free energy is available in profusion, and Noether shrieks.

No new physics?

No. 2 is not quite correct since all of the "free energy" schemes have circular terms in the Hamiltonian and only the acceleration to spacial seperation looks that way.  Noether snoozes.
Well, in that case I must ask you to go through my equations and to spot the error.

? ? ? http://emdrive.echothis.com/Theory ?
Nope.
Well, in that case I must ask you to go through my equations and to spot the error. :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 11:17 PM
...Great video.  It touches on so many topics that get discussed here on this forum.

...I thoroughly enjoyed this, Thanks Dr. Rodal!!!
As PhaseShift said it is interesting how this video deals with a number of topics we have been discussing.  For example, the question is asked (by somebody at CERN) to Sundrum as to whether there is a relation of the extra dimension(s) to the Quantum Vacuum virtual particles.  The answer is that this is unknown.  They are using Heisenberg's uncertainty principle as a given.  Sundrum emphasizes the fact that we can borrow much larger amounts of energy than we own (no need of collateral) but that you have to pay it back in an extremely small amount of time.  They are using this ability to borrow larger energy from the QV in their experiments to explore energy being lost in the extra dimension(s). Thus, the issue with Dr. White's proposal is the need to payback, in a very small amount of time, any energy you may borrow (the QV being immutable and non-degradable over longer periods of time).  Essentially, Dr. White's proposal is that one can default on the mortgage  :)
Ahhh the Quantum Vacuum, the QV. If there wasn't so much evidence that it exists as appearing and disappearing particles and forces from somewhere out of the planck levels of space and possible links into another dimension of space time, I'd think QV is a Genie in the bottle.
Reading about the QV http://en.wikipedia.org/wiki/Vacuum_state
What is that time period I need to "give it back"? a femtosecond, 1 week, a couple years, the forecast age of the universe? I'm not sure if it is a set time as we see it. And what if I warped, just a little and just enough spacetime with an EM field, would that have an effect of the borrowed time and during that time I had it couldn't I just strip of a little something extra before I gave it back?
My head is feeling a little mushy and I think I need some hot tub time with something cold.
To all, thanks for putting up with me and my crackpot ideas of our world.
I asked this question here because when I told my grandson who is in first year engineering asked me almost this very same question.  I said virtual particles really don't exist except in calculations and mostly are not or can not be observed in the real world. He sent me this from Wikipedia and said not true. Could anyone help me here to put this into a easier form to understand? Thanks
http://en.wikipedia.org/wiki/Virtual_particle
(...)

QFT is even weirder than that! It must be thought of in terms of "information" rather than propagation. When an electron moves from point A to point B, it doesn't move through space-time. It is "annihilated" at point A and "created" at point B. Why? Because this is what we observed, what was at A is now at B, but we did not "observe" the particle between those 2 points, at the quantum scale. There are an infinite number of paths it could have taken, but we do not have that information. QM is based on what is observable, i.e. Heisenberg!

I think the best example is the DC electric field of a capacitor. It is conveyed by virtual photons. They can only be observed by the force they exert on charged matter, but in that regard, the "effects" of virtual particles are observable, if not the particles themselves.



Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/24/2015 11:37 PM
...
aahhh... that would make sense...
basically he's describing the radiation pressure on both front and back plate...
http://en.wikipedia.org/wiki/Radiation_pressure#/media/File:Sail-Force1.gif

damn..you really have a gift of writing things out in a clear and layman-understandable way...

but from a radiation pressure point of view, part of the big plate and the totality of the front plate nullify each other, so if there is a difference to be observed, shouldn't it be in the difference between the angled sides and the small left over of (big plate - small plate)?

The fact that the sidewalls are angled give me the impression that electromagnetic waves will bounce more often on the sidewalls of the frustum when going towards the small end, then when going towards the big end.
This is because reflection angles on the sidewalls are steeper when going to the small end, and more shallow going the other direction.

Now... a silly idea/question...

but is the size of a force/momentum truly linear with the angle of incidence?
cause, if a force would be a bit less then linear for a shallow angle, that could account for the residual force towards the small end?
Are there any studies about momentum/force transfer for electromagnetic waves when reflected?

Probably talking nonsense here, but you never know, even a blind man can hit a target.. :-[

Thank you.

Shower uses the notion that the wave velocity is also different at the small end (slower) than at the big end. But then he uses special relativity to subtract the 2 velocities, and gets a NET force. His derivation is not correct on so many levels, but it is correct to say that the forces do not sum to zero.

You have the right idea. The taper toward the small end will offer greater attenuation than the taper toward the large end. The energy for Q is stored energy. As it is dissipated, that dissipation occurs asymmetrically.  The paper by Zeng & Fan show graphs of the attenuation factor at various taper angles and frequencies. Though they are referring to a waveguide, not a frustum cavity.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-17-1-34



Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/24/2015 11:45 PM
Yang doesn't take the free dynamics bull by the horns.

Also, if she's using heat dissipation as an explanation, how does this system manage  not to be a photon rocket?

(...)

No idea how she can get Force/InputPower thousands of times better than perfect photon rocket.

(...)

Make Q a cyclic, time dependent, PWM duty cycle controlled function, not a constant!

It charges until it has enough thrust to overcome the resistance of the mass, but once it moves, that energy is dissipated. P drops back to Pin and Q has to build up again. I don't see any other way...

But looking at Yang's paper, she does not perform an ON-OFF duty cycle analysis of her EM Drive.  Her calculations are ON, steady state, harmonic, for indefinite amount of time.

So the question remains unanswered as to how her Finite Element calculations can result in a performance of her EM Drive thousands of times more efficient than a perfectly collimated  photon rocket.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/25/2015 12:06 AM
...
I asked this question here because when I told my grandson who is in first year engineering asked me almost this very same question.  I said virtual particles really don't exist except in calculations and mostly are not or can not be observed in the real world. He sent me this from Wikipedia and said not true. Could anyone help me here to put this into a easier form to understand? Thanks
...
Well, I prefer the answer given in the previous video by Randall's co-author Raman Sundrum ( http://forum.nasaspaceflight.com/index.php?topic=37642.msg1379064#msg1379064 ), but here is a Prof. that agrees with the answer you gave to your grandson, for another point of view (in case you didn't see it):

http://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/25/2015 01:14 AM
...
I asked this question here because when I told my grandson who is in first year engineering asked me almost this very same question.  I said virtual particles really don't exist except in calculations and mostly are not or can not be observed in the real world. He sent me this from Wikipedia and said not true. Could anyone help me here to put this into a easier form to understand? Thanks
...
Well, I prefer the answer given in the previous video by Randall's co-author Raman Sundrum ( http://forum.nasaspaceflight.com/index.php?topic=37642.msg1379064#msg1379064 ), but here is a Prof. that agrees with the answer you gave to your grandson, for another point of view (in case you didn't see it):

http://profmattstrassler.com/articles-and-posts/particle-physics-basics/virtual-particles-what-are-they/
Thanks for the great links, I sent them to him and told him to read and study. I think he was trying to set old grandma up. ;)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/25/2015 01:26 AM
...
She said; "(2) The calculation of the different modes and different cavity structure, the mode TM012 which has smallest cavity Large-End has the largest thrust, so has the highest quality factor and thrust. Mode TM011 thrusters has the worst performance."

So a narrower cone angle, and a TM012 mode. What's wrong with that? The TM011 mode is not bad, but requires a larger cone, so of course it will be weaker. I actually think this is theoretically correct.
...

The translation of Chinese to English seems to be low quality: the translation text states TM012 mode (as you wrote) but the original Chinese text reads TE012 instead (which is correct, as TM012 is at significantly higher frequency !!)
The original Table 1 in Chinese shows larger geometrical dimensions for mode TE012 than the geometrical dimensions used for TM011.

So, no the geometrical dimensions for mode TE012 and TM011 are such that the dimensions for TE012 were larger than for TM011.

Please take a gander and let me know what you think:


Looking at her chart, Figure 3, the TM012 mode should be a good one too, but I'll take your word for it.

The horizontal axis of Figure 3 is (D/L)^2, so a larger number indicates larger diameter, shorter length. It defines the aspect ratio of the two, not the physical dimensions. No? What am I missing?



Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/25/2015 01:46 AM
..Looking at her chart, Figure 3, the TM012 mode should be a good one too, but I'll take your word for it.

The horizontal axis of Figure 3 is (D/L)^2, so a larger number indicates larger diameter, shorter length. It defines the aspect ratio of the two, not the physical dimensions. No? What am I missing?
I re-wrote my post:


The translation of Chinese to English seems to have issues: the translation text states TM012 mode (as you wrote) but the original Chinese text reads TE012 instead (which is correct).


They kept the small diameter constant and they considered different big diameters and heights.  The big diameter is a variable.

The original Table 1 in Chinese shows larger truncated cone heights for mode TE012 than the heights used for TM011.


I think that the translation should be:

Quote
(2) For the calculation of the different modes and different microwave cavity structures, for the mode TE012 the cavity which has the minimum diameter at the large end has the largest thrust and the highest quality factor. Mode TM011 thrusters has the worst performance. (3) As the Large-End diameter of the cavity increases, the height of cavity is reduced, cavity volume and wall surface area also reduced, leading to low quality factor and producing less thrust

Later on, in the last section, the translation states:

Quote
Calculation show that under the four modes, TE011, TE012, TE111 and TM011, the quality factor of TE012 is highest and with highest thrust, followed by TE011. With the Small End of the cavity unchanged, the quality factor and thrust decrease with the increase in the Large End

So, again best modes recommended by Prof. Yang are Transverse Electric TE012 followed by TE011, instead of the Transverse Magnetic modes recommended by Shawyer and the Transverse Magnetic mode (TM212) presently used by NASA.

Please take a gander and let me know what you think (notice that the table gives the "height" in mm of the truncated cone:

two heights were considered for TE012: 240 mm and 175 mm

two heights were considered for TM011: 150 mm and 122 mm

clearly TE012 and TE011 had the best numbers of all the modes considered (TE011, TE012, TE111 and TM011)

Notice that the heights of Prof. Yang's cavities are smaller than NASA's and Shawyer's



Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/25/2015 02:15 AM
...
Looking at her chart, Figure 3, the TM012 mode should be a good one too, but I'll take your word for it.

The horizontal axis of Figure 3 is (D/L)^2, so a larger number indicates larger diameter, shorter length. It defines the aspect ratio of the two, not the physical dimensions. No? What am I missing?
But the vertical axis in Figure 3 does not appear to be thrust force, so how do you know that TM012 should be a good one?

And, when the time comes for her to calculate the thrust force (Table 2) she does not consider TM012

Okay, so my take on the vertical axis was that it represented Q somehow, but I admit it is unclear to me what that vertical axis represents. If it does represent Q, it shows that the TE012 mode cavity requires a longer length and smaller big diameter than the TM01 mode, for the same Q value. I'm assuming that is the case for the TM012 mode as well, showing it requires longer length and smaller big diameter than TM011 or TE111.

What's your take on it?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/25/2015 02:26 AM
...
Looking at her chart, Figure 3, the TM012 mode should be a good one too, but I'll take your word for it.

The horizontal axis of Figure 3 is (D/L)^2, so a larger number indicates larger diameter, shorter length. It defines the aspect ratio of the two, not the physical dimensions. No? What am I missing?
But the vertical axis in Figure 3 does not appear to be thrust force, so how do you know that TM012 should be a good one?

And, when the time comes for her to calculate the thrust force (Table 2) she does not consider TM012

Okay, so my take on the vertical axis was that it represented Q somehow, but I admit it is unclear to me what that vertical axis represents. If it does represent Q, it shows that the TE012 mode cavity requires a longer length and smaller big diameter than the TM01 mode, for the same Q value. I'm assuming that is the case for the TM012 mode as well, showing it requires longer length and smaller big diameter than TM011 or TE111.

What's your take on it?
Table 3, page 28 of the original Chinese paper shows:



Vertical Axis: ( (Frequency[Hz] * Diameter[cm] )/(Hz*cm) )2 * 10- 20



Horizontal Axis:  (Diameter / Height)2



I didn't have the time yet to chase what Diameter is she referring to.

To me it is a table for mode shapes in terms of natural frequency and geometry.

Let me know what you think
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zellerium on 05/25/2015 03:39 AM
I'm glad to see the discussion move away from Shawyer and back to examining the experiment by Yang; her apparatus seems to work the best, which probably contributes to her reluctance to share information. A friend of mine who recently moved from China has told me NWPU is heavily tied with the Chinese military, and has one of the best aerospace programs in the country. I sent a translated email to Dr. Yang on Monday with a few questions, but no response yet.

A couple interesting things I have noticed about her experiments:
The depiction of the input port of the frustum has changed a few times, from the center to closer to the top and bottom.
Does anyone know what year this first picture is from? [Edit: found the paper it came from here http://wulixb.iphy.ac.cn/EN/abstract/abstract60316.shtml but it isn't translated] I would guess it is a later design. The two rods look like some kind of tuning mechanism. It also looks like they have an adjustable aperture. Seems a lot like Todd's Conjecture to me, a symmetric resonant cavity to build up energy, and distribute it to the frustum to attenuate the wave. 

I've been looking into the different methods of power delivery and now I am leaning towards trying the setup by Yang first. (We'll have plenty of time to try other methods if it doesn't work out) I'm thinking we should put the magnetron antenna directly inside an aluminum tube (through the side to activate the TE modes)  which feeds to the frustum at 15% of the height from the large end. We could have an adjustable plate on the inside of the tube as well as the frustum to change lengths. I'm still trying to figure out if we can put a magnetron in our vacuum chamber, I expect overheating to be an issue. Also I believe the casing is made of steel which our professor won't allow in the chamber because of outgassing. Backup plan is to use an intermediate cavity to convert magnetron output to coax and feed that into the chamber.   

By the way, Cal Poly Connect has given us the full amount of funding we requested, enough to rent a signal generator, 50 W amp, and a spectrum analyzer. We also have extra money to try some different dimensions and we're working on getting the RF module of COMSOL. We're not going to rent the equipment until after we have already tried using the magnetron because the resolution of our thrust measurement system is estimated ~1 mN at best. A clean signal at 50 W probably won't give us anything we can see.
 
We're putting together a summary of our experimental design that I'll post in the next couple of days.

Happy to see everyone still thinking  :)

Kurt
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/25/2015 05:08 AM
Two words: Ning Li

Be afraid. Be very afraid :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/25/2015 05:16 AM
(...)
Table 3, page 28 of the original Chinese paper shows:



Vertical Axis: ( (Frequency[Hz] * Diameter[cm] )/(Hz*cm) )2 * 10- 20



Horizontal Axis:  (Diameter / Height)2



I didn't have the time yet to chase what Diameter is she referring to.

To me it is a table for mode shapes in terms of natural frequency and geometry.

Let me know what you think

She's saying to;

1. Choose the mode you want to operate in.
2. Choose the small diameter based on the cut-off of that mode.
3. Choose the large diameter and height based on Figure 3, (D/L)^2 as the aspect ratio.

On the horizontal axis, 0 is the cut-off diameter. On the vertical axis, D is the average diameter and f is the frequency of the mode. So it represents the average wave velocity of that mode, in the waveguide, squared, but I don't understand the 10^-20 yet unless it's just unit fixing.

I also think I found a (minor?) error in the 2013 paper. In my estimation, equations 4 and 6 are correct. Where I disagree is that her premise is that there are charged particles in the volume, and then on equations 7 and 8, she removes the particle momentum density and the energy density of the field, for no apparent reason and then IMO, she abruptly ends the section.

What I think it "should" be is the following;

Equation 4 is straightforwardly interpreted as the input power of the field, is absorbed by the particles of the frustum. The Div(S) through the frustum is zero, (by definition) leaving only the time derivative of the energy density of the field and the energy density of the particles. The particles may be interpreted as the charged particles of the frustum, negative electrons and positive lattice ions, accessible through the skin effect. There are current and charge densities just as she described, stored in the metal as inductive and capacitive energy density, so Wp is not zero. The reactive power Pe, and Ph, and losses Pr, are not zero. So Power in x time = energy  stored + energy lost.

Equation 6 is also interpreted similarly. The divergence of the tensor on the RHS is zero, by definition there is nothing coming out of the frustum. This leaves only the LHS which says that the force on the particles is opposite the force on the field, action = reaction. The particle momentum density, Gp term must be split into positive and negative contributions, and relative masses. Then the momentum lost by the field, is gained by some distribution of these charged particles, the NET result is propulsion.

Her force analysis is missing a duty cycle, but other than that I think it's still correct. Because, even though the divergence of the tensor is zero, it is zero because there is an opposing pressure from the walls of the frustum caused by the skin effect, that prevents the field from escaping. The action = reaction forces on the LHS of equation 6 that I spoke of above, are equal to the pressures she's integrating on the surface. Integrating the pressures is easier than integrating the scattering of every photon with lattice ions and electrons.

Todd
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: ThinkerX on 05/25/2015 05:38 AM
Ning Li

http://en.wikipedia.org/wiki/Ning_Li_(physicist)

Looks a bit 'out there,' but maybe something can be salvaged from the papers?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/25/2015 05:47 AM
It's a bit late for salvage.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 07:14 AM
This discussion is clearly interminable, in the literal sense of that word. Whatever experimental results accrue, in past, present or future, there will always be doubt. This is why I am so strongly in favour of a space-based test. I've already laid out my reasons. Without that, I'd lay odds that one could return to this forum in years to come and people would still be arguing the toss.

Let's cut the Gordian Knot!

The test program I  plan to run will remove ALL doubt that the EMDrive generates real propellantless thrust without needing a space test.

One of my goals is to be able to hold the EMDrive & while switching it on and off, to be able to FEEL the thrust.

You may have posted it somewhere before Traveller, but I haven't had the chance to read the entirety of threads 1 and 2.  Do you have a general idea of what kind of timeline you are going to be working off of with your test program?  Do you expect to have a build ready in the next two months, with another month or two for testing, or do you expect it take longer?

Just trying to get a sense of experimental development on this device given we can't expect EW results until at least late July.

Have purchased most of the electronics and started work writing the USB based control & data logging software.

Balance beam & Faraday Cage designs are finished.

Working on the test protocols, which will be published here to get feedback on how to improve to reduce / eliminate doubt.

Working on the interactive design spreadsheet so I can feed back test data to improve the model.

Expect to build the frustum in 3-4 weeks & start test right away as in working out the best way to excite it in TM mode, getting resonance & impedance matching at low power of 1 watt. So fair amount of work to do before using the balance beam. BTW plan to copy Mullerton with the clips to attach the end plates so I can easily get inside access.

Everything will be videoed, logged & made available on YouTube.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 11:37 AM
2 question to the group:

Plan is to laser cut all the pieces from 0.5mm thick copper sheet. Have found a company that can do a proper roll of the frustum so the side joint is a butt joint. Same company can form the spherical end plates.

1) UL certified Copper epoxy will be used to join the 2 end flanges to the frustum and then cover the butt joint.
http://www.supergluecorp.com/super-glue/epoxies/copper-bond

Does anyone have an opinion on this joining method?


2) 5mm in from each frustum end and around the middle there will be 8 laser cut, equally, spaced 2mm diameter holes through the frustum side wall (24 in total) to allow hot air to escape the frustum, so as to very significantly reduce / eliminate buoyancy.

Is this an effective way to deal with buoyancy issues?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Paul Novy on 05/25/2015 11:52 AM

Plan is to laser cut all the pieces from 0.5mm thick copper sheet. Have found a company that can do a proper roll of the frustum so the side joint is a butt joint. Same company can form the spherical end plates.

1) UL certified Copper epoxy will be used to join the 2 end flanges to the frustum and then cover the butt joint.
http://www.supergluecorp.com/super-glue/epoxies/copper-bond

Does anyone have an opinion on this joining method?


I would go for an old fashioned soldering.  Why introduce another unknown variables caused by the glue?

BTW. I wanted to say Hi to the whole community. I've been around for a while reading, now I'll try to throw my 5 cents from the point of view of a mechatronic engineer... well if I have something useful to say.

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 12:04 PM

Plan is to laser cut all the pieces from 0.5mm thick copper sheet. Have found a company that can do a proper roll of the frustum so the side joint is a butt joint. Same company can form the spherical end plates.

1) UL certified Copper epoxy will be used to join the 2 end flanges to the frustum and then cover the butt joint.
http://www.supergluecorp.com/super-glue/epoxies/copper-bond

Does anyone have an opinion on this joining method?


I would go for an old fashioned soldering.  Why introduce another unknown variables caused by the glue?

BTW. I wanted to say Hi to the whole community. I've been around for a while reading, now I'll try to throw my 5 cents from the point of view of a mechatronic engineer... well if I have something useful to say.

Thanks for the comment.

I have concerns about the frustum warping when using soldering. Have built stuff before using thin copper plate, know it moves and the final soldered positions may not be the unsoldered position.

As I see it, making sure the 2 end plates are highly parallel and joined to the frustum at the same angle ensures the highest Q I can get. Using a cold assembly method should ensure the money I'm paying for laser cutting, to ensure everything is at the right angles to each other, will pay dividends.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/25/2015 12:39 PM
You'll need to verify how the epoxy glue reacts to temperature, because your frustum will get hot...
Migth also need to roughen the exterior to give the epoxy a better adherence.

0.5mm thickness will most likely warp when soldering, so I'd go for the glue+strip on the outside.

Then the challenge will be to get the 2 edges align according the curve of the cone, as they will tend to angle. The strip you place on top of it, will need to be slightly curved also...
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/25/2015 12:48 PM
@TheTraveller
Re. the join - you may find that you don't get all the way down to the original resistivity with that approach, and the EM will see a resistive discontinuity, which will distort mode shapes in some way. But I can't say if this is a major or minor effect. Indium might be better, but I'm unsure how you'd apply it. It's usually used in a pressure fit. My gut tells me that what you propose is good enough.

Re. the RF feed - you'll want to do all drilling (air vents too) before soldering the final end cap on, else you might leave copper scurf rattling around in there. This will tend to lower the Q. The placement of the RF feed hole is rather chicken-and-egg because you won't know the impedance to be matched until you use it. That's unless you or someone else can calculate it. This problem is exacerbated if you don't have variable frequency ability. Perhaps instead you're going for the variable end plate approach. In any case, you're going to need something to do the impedance matching. Paul March started out using a "trombone" style matcher for this, and now has something considerably more sophisticated.

Re. venting heated air - this will cause the weight to change as dm = d(rho)*V*g Newton, where d(rho) is the change in air density between the two temperatures and V is the cavity volume. If you are weighing the cavity then this will obviously be a significant factor. Fortunately it can be cancelled away by flipping  the cavity upside down, since then
F + dm = apparent (measured) upthrust = weight loss
F - dm = apparent  (measured) downthrust = weight gain
where F is the true thrust.
Solve for F, dm as usual:
F   = (up + down) / 2
dm = (up - down) / 2
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 01:45 PM
You'll need to verify how the epoxy glue reacts to temperature, because your frustum will get hot...
Migth also need to roughen the exterior to give the epoxy a better adherence.

0.5mm thickness will most likely warp when soldering, so I'd go for the glue+strip on the outside.

Then the challenge will be to get the 2 edges align according the curve of the cone, as they will tend to angle. The strip you place on top of it, will need to be slightly curved also...

Plan to use a machine shop that can do a roll to ensure the final rolled frustum is aligned at each corner as well as along the butt seam.

Will then place the laser cut flange on a glass table (so I can observe what is happening from the under side).

Next will insert the appropriate end of the frustum inside the flange that has a laser cut ID to match the frustum OD.

Then place a thin glass plate on the top of the frustum other end to ensure slight but equal pressure on all sides of the frustum.

Next, once I can see there is contact along the full circumference of the frustum end with the glass table, will then epoxy, from outside, the entire seam, following the recommended procedure to get a strong and long lasting seam as per the UL certification for the epoxy.

Once cured, will flip it over and repeat for the other ends flange.

Lastly will epoxy the side wall butt seam.

The air holes will be laser cut, so no need to worry about swaft inside the frustum.

The curved end plates will be sandwiched between the epoxied on flange and a flat covering plate, with the three layers held together by Mulletron's clips. This will enable internal access, the ability to alter the antenna arrangement and position, the ability to quickly change end plates and by using thin spacer rings, to alter the frustum's physical length.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 01:59 PM
@TheTraveller
Re. the join - you may find that you don't get all the way down to the original resistivity with that approach, and the EM will see a resistive discontinuity, which will distort mode shapes in some way. But I can't say if this is a major or minor effect. Indium might be better, but I'm unsure how you'd apply it. It's usually used in a pressure fit. My gut tells me that what you propose is good enough.

Re. the RF feed - you'll want to do all drilling (air vents too) before soldering the final end cap on, else you might leave copper scurf rattling around in there. This will tend to lower the Q. The placement of the RF feed hole is rather chicken-and-egg because you won't know the impedance to be matched until you use it. That's unless you or someone else can calculate it. This problem is exacerbated if you don't have variable frequency ability. Perhaps instead you're going for the variable end plate approach. In any case, you're going to need something to do the impedance matching. Paul March started out using a "trombone" style matcher for this, and now has something considerably more sophisticated.

Re. venting heated air - this will cause the weight to change as dm = d(rho)*V*g Newton, where d(rho) is the change in air density between the two temperatures and V is the cavity volume. If you are weighing the cavity then this will obviously be a significant factor. Fortunately it can be cancelled away by flipping  the cavity upside down, since then
F + dm = apparent (measured) upthrust = weight loss
F - dm = apparent  (measured) downthrust = weight gain
where F is the true thrust.
Solve for F, dm as usual:
F   = (up + down) / 2
dm = (up - down) / 2

Will be using a variable Rf generator that can alter freq in 1kHz steps, even at 3.85GHz.

No swarf as the holes are laser cut when the frustum is cut.

I have some thin copper mesh strips and silver epoxy that I intend to use along the side wall seam. Then after several layers, will overlayer with the Copper Epoxy, which also bonds other metals. It would appear Shawyer did something similar in his 1st Experimental unit as per the attached image.

As my 1st step is to excite the frustum in TM mode, the plan is to use a stud antenna in the centre of the small end. Once I get resonance at close to what my spreadsheet model predicts, will then apply 1W at that frequency and start playing with antenna position and impedance matching before ramping up the power to my max 100W.

I do believe what we see in the 2nd image to the left of the Red RF feed may not be an impedance matching system but instead an arm that extends inside the Flight Thruster such that Shawyer can fine tune the antenna position. It appears to have a small arm / crank on the left end and the ability to slide in and out.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/25/2015 02:01 PM
(...)Vertical Axis: ( (Frequency[Hz] * Diameter[cm] )/(Hz*cm) )2 * 10- 20...
... I don't understand the 10^-20 yet unless it's just unit fixing...
Fig. 3, p.7 of translated paper http://www.emdrive.com/NWPU2010translation.pdf

The factor of 10-20 is necessary to avoid writing a huge number on the plotted vertical axis, mainly because the frequency units used by the authors are in Hz instead of GHz.

For example, take a value of "18" in the vertical axis, this really means 18*1020, which when multiplied by 10-20, gives 18.

If she would have used GHz (1 GHz = 109 Hz) instead of Hz as the unit for frequency, the factor would have to be instead (109)2 * 10-20 = 10-2
Also, if in addition to using GHz instead of Hz units,  she would have used decimeters (1 decimeter = 10 centimeters) as the unit of length, there would be no need for multiplying factor at all.
So, you can read the units in the Figure 3 as being given in GHz for frequency and decimeter for length, and that avoids the factor of  10-20
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/25/2015 02:20 PM
...I also think I found a (minor?) error in the 2013 paper. In my estimation, equations 4 and 6 are correct. Where I disagree is that her premise is that there are charged particles in the volume, and then on equations 7 and 8, she removes the particle momentum density and the energy density of the field, for no apparent reason and then IMO, she abruptly ends the section....
Can you please elaborate why youthink this is, maybe, just a (minor) error by Prof. Yang and her co-authors?

(And by the way, I am looking at the 2010 paper, not the 2013 paper, in my comments below)

They write (2010 paper, translation page 4,  original page 28)

http://www.emdrive.com/NWPU2010translation.pdf
Quote
If the microwave electromagnetic field consists of charge particles, due to the
electromagnetic force, the charge particles can travel within the electromagnetic
field, so the charge particles can acquire energy and momentum from the
electromagnetic field. This indicates that electromagnetic field have energy and
momentum.

The microwave electromagnetic field inside the cavity is composed of photons (at microwave frequencies), which as we all know, have no charge whatsoever.  So the microwave electromagnetic field does not consist of charge particles (unless one considers the virtual particles of the QV or one considers ionized air).  This is the difference between Greg Egan's equations http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html, who finds no net thrust force, since he doesn't consider this term at all.

If there are any charges and currents, they are only present in the copper metal (translation says "brass"), and not inside the empty microwave cavity.  This seems to me a major issue, and not a minor point.



The original 2010 paper in Chinese (http://www.emdrive.com/NWPU2010paper.pdf) says (my translation)

Quote
The microwave electromagnetic field of charged particles , if present , due to the electromagnetic force 

The "if present" seems to have been translated to "if it consists of".  Either way, "If present" or "if it consists of" is a big if.   We have to understand whether this condition is met, and if so, what are these charged particles.

Are the authors considering charged particles to be present in the empty cavity?

In essence are the authors effectively considering virtual charged particles like the QV of Dr. White ?

Or are the authors considering having ionized air inside the cavity ?
  (one example:  http://www.jpier.org/PIERM/pierm26/20.12101201.pdf  )

(http://www.awakening-healing.com/Healthy_Products/Images/decompose2.jpg)

(http://www.globalspec.com/ImageRepository/LearnMore/201212/ionizer01f4a926e561a74a08bc672e5218f6cbc7.png)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/25/2015 02:29 PM

Plan is to laser cut all the pieces from 0.5mm thick copper sheet. Have found a company that can do a proper roll of the frustum so the side joint is a butt joint. Same company can form the spherical end plates.

1) UL certified Copper epoxy will be used to join the 2 end flanges to the frustum and then cover the butt joint.
http://www.supergluecorp.com/super-glue/epoxies/copper-bond

Does anyone have an opinion on this joining method?


I would go for an old fashioned soldering.  Why introduce another unknown variables caused by the glue?

BTW. I wanted to say Hi to the whole community. I've been around for a while reading, now I'll try to throw my 5 cents from the point of view of a mechatronic engineer... well if I have something useful to say.

Thanks for the comment.

I have concerns about the frustum warping when using soldering. Have built stuff before using thin copper plate, know it moves and the final soldered positions may not be the unsoldered position.

As I see it, making sure the 2 end plates are highly parallel and joined to the frustum at the same angle ensures the highest Q I can get. Using a cold assembly method should ensure the money I'm paying for laser cutting, to ensure everything is at the right angles to each other, will pay dividends.

That epoxy is not electrically conductive, is it? It's for pipes, not circuits so the electrical connection for currents to flow from end plates to side walls may be compromised. Try this;

http://www.mgchemicals.com/products/adhesives/electrically-conductive/silver-conductive-epoxy-8331/



Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 02:40 PM

Plan is to laser cut all the pieces from 0.5mm thick copper sheet. Have found a company that can do a proper roll of the frustum so the side joint is a butt joint. Same company can form the spherical end plates.

1) UL certified Copper epoxy will be used to join the 2 end flanges to the frustum and then cover the butt joint.
http://www.supergluecorp.com/super-glue/epoxies/copper-bond

Does anyone have an opinion on this joining method?


I would go for an old fashioned soldering.  Why introduce another unknown variables caused by the glue?

BTW. I wanted to say Hi to the whole community. I've been around for a while reading, now I'll try to throw my 5 cents from the point of view of a mechatronic engineer... well if I have something useful to say.

Thanks for the comment.

I have concerns about the frustum warping when using soldering. Have built stuff before using thin copper plate, know it moves and the final soldered positions may not be the unsoldered position.

As I see it, making sure the 2 end plates are highly parallel and joined to the frustum at the same angle ensures the highest Q I can get. Using a cold assembly method should ensure the money I'm paying for laser cutting, to ensure everything is at the right angles to each other, will pay dividends.

That epoxy is not electrically conductive, is it? It's for pipes, not circuits so the electrical connection for currents to flow from end plates to side walls may be compromised. Try this;

http://www.mgchemicals.com/products/adhesives/electrically-conductive/silver-conductive-epoxy-8331/

As mentioned I have silver epoxy and will be using it as the 1st 2 layers, then using the Copper/Metal epoxy for an overcoat. My experience with silver epoxy is that it doesn't have a lot of strength and can't be replied on to generate a physically strong joint.

Note Shawyer used epoxy to attach the side Rf fitting in the 1st Experimental unit as well it seems on the side wall joint and part of the flange joint.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zaphod_vi on 05/25/2015 02:56 PM
I'll have to return to this quote again.

Quote
What the EmDrive thruster does is to produce a force, which we call the thrust, in one direction. This is a force that you can measure. If you put your hand against the end plate that's producing the thrust you'll feel it pushing against you. And, as with all machines that follow Newton's principles, it will therefore accelerate in the opposite direction. So this is not a reactionless thruster, because those things just don't exist outside of science fiction, but it is a propellantless thruster.

This behaviour with a force being felt from the "thrusting" end plate is also, assuming it is large enough, consistent with pressing on a bend in space time.

If space time is being bent, and the bend is symmetrical, the non-thrusting (smaller) end plate should have an opposite attracting (pulling) force rather than a repulsive (pushing) force.

Could these forces be detected by Iulian in his test setup. So, rather than hang the drive on the scales, place the drive on the floor, then hang a weight on the scale that lies as close to the end plate as possible. Then repeat for the other plate.

On a separate note, is it correct to say that the drive, as described by Shawyer has a duty cycle. That is it behaves like a pulse jet with bursts of thrust (v1 doodlebug). If so, is there experimental data to confirm this, or is the duty cycle so fast that it gets averaged out in measurement.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/25/2015 03:16 PM
...I also think I found a (minor?) error in the 2013 paper. In my estimation, equations 4 and 6 are correct. Where I disagree is that her premise is that there are charged particles in the volume, and then on equations 7 and 8, she removes the particle momentum density and the energy density of the field, for no apparent reason and then IMO, she abruptly ends the section....
Can you please elaborate why you think this is just a minor error by Prof. Yang and her co-authors?

(And by the way, I am looking at the 2010 paper, not the 2013 paper, in my comments below)

They write (2010 paper, translation page 4,  original page 28)

http://www.emdrive.com/NWPU2010translation.pdf
Quote
If the microwave electromagnetic field consists of charge particles, due to the
electromagnetic force, the charge particles can travel within the electromagnetic
field, so the charge particles can acquire energy and momentum from the
electromagnetic field. This indicates that electromagnetic field have energy and
momentum.

The microwave electromagnetic field inside the cavity is composed of photons (at microwave frequencies), which as we all know, have no charge whatsoever.  So the microwave electromagnetic field does not consist of charge particles.  This is the difference between Greg Egan's equations http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html, who finds no net thrust force, since he doesn't consider this term at all.

If there are any charges and currents, they are only present in the copper metal (translation says "brass"), and not inside the empty microwave cavity.  This seems to me a major issue, and not a minor point.



EDIT: The original in Chinese says (my translation)

Quote
The microwave electromagnetic field of charged particles , if present , due to the electromagnetic force 

The "if present" seems to have been changed in the translation to "if it consists of".  Either way, "If present" or "if it consists of" is a big if.   We have to understand whether this condition is met, and if so, what are these charged particles.

Are the authors considering charged particles to be present in the empty cavity?

In essence are the authors effectively considering virtual charged particles like the QV of Dr. White ?

Or are the authors considering having ionized air inside the cavity ?


All good points. I believe she is trying to facilitate using Maxwell's equations by imagining there are particles inside the volume. Maxwell's equations are difficult, this is a crutch. Where she is making her mistake is that there actually are charged particles inside the volume, (besides air) they are not imaginary, they are confined to within the skin effect depth of the metal. The skin effect is inside the volume of integration for the Divergences, and it contains both positive and negative charges. Typically, we ignore the force acting on the lattice ions, since their mass is so much greater than the electrons, but they are there and they do scatter, vibrate and transfer momentum from the field to the frustum.

Unfortunately, she does not elaborate on the actual expressions of E and H, that would depend on the geometry, attenuation, phase, etc... she leaves that to the results table of her FEA. But the force equation she ends up with is still the correct equation. Its correctness, as always, depends on the accuracy of what you plug-in for E and H at the boundary, and the duty cycle of the power consumption. Therefore, if you know what to plug in, it's only a "minor" issue in her example and explanation, not in the actual FEA which is supposedly a realistic simulation of a brass cavity.


Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/25/2015 03:25 PM
...As mentioned I have silver epoxy and will be using it as the 1st 2 layers, then using the Copper/Metal epoxy for an overcoat. My experience with silver epoxy is that it doesn't have a lot of strength and can't be replied on to generate a physically strong joint...
The silver epoxy has a film thickness dependent conduction behavior (due to the percolation behavior of the conductive particles and the viscosity of the epoxy).  The resistivity levels are reduced as the adhesive film thickness increases. Conversely, when the thickness is reduced significantly, a significant increase in resistivity is observed coupled with a significant increase in the slope of the resistivity-thickness curve.  On the other hand, as the thickness increases, the strength decreases, mainly because the residual stresses are larger with larger layer thickness (the epoxy is stress free near the cure temperature, which is much higher than room temperature).  So, getting it right is an art  :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 03:26 PM
I'll have to return to this quote again.

Quote
What the EmDrive thruster does is to produce a force, which we call the thrust, in one direction. This is a force that you can measure. If you put your hand against the end plate that's producing the thrust you'll feel it pushing against you. And, as with all machines that follow Newton's principles, it will therefore accelerate in the opposite direction. So this is not a reactionless thruster, because those things just don't exist outside of science fiction, but it is a propellantless thruster.

This behaviour with a force being felt from the "thrusting" end plate is also, assuming it is large enough, consistent with pressing on a bend in space time.

If space time is being bent, and the bend is symmetrical, the non-thrusting (smaller) end plate should have an opposite attracting (pulling) force rather than a repulsive (pushing) force.

Could these forces be detected by Iulian in his test setup. So, rather than hang the drive on the scales, place the drive on the floor, then hang a weight on the scale that lies as close to the end plate as possible. Then repeat for the other plate.

On a separate note, is it correct to say that the drive, as described by Shawyer has a duty cycle. That is it behaves like a pulse jet with bursts of thrust (v1 doodlebug). If so, is there experimental data to confirm this, or is the duty cycle so fast that it gets averaged out in measurement.

Shawyer did show in the superconducting engine that each of the 8 cavities would only be excited, in series, for a fraction of one TC. So a duty cycle of 1:8 with excitation only lasting for less than 1 TC. As it takes 5 TC to fully change, with such a high Q, the time to charge may be way too long.

Shawyer made comment on charge time and duty cycle. Page 5 of attached.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/25/2015 03:32 PM

If space time is being bent, and the bend is symmetrical, the non-thrusting (smaller) end plate should have an opposite attracting (pulling) force rather than a repulsive (pushing) force.

Could these forces be detected by Iulian in his test setup. So, rather than hang the drive on the scales, place the drive on the floor, then hang a weight on the scale that lies as close to the end plate as possible. Then repeat for the other plate.


That's an interesting experiment in that it is independent of the cavity errors.  If we look at something like Eq. 14 in Marco's paper, we might expect to see nothing for a perfectly conducting cavity.  Copper isn't perfect, so there may be an effect due to dielectric (or magnetic) leakage.  In any event, an independent weight measurement would be much less noisy, I would think.  (so more sensitive, as required)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 03:33 PM
...As mentioned I have silver epoxy and will be using it as the 1st 2 layers, then using the Copper/Metal epoxy for an overcoat. My experience with silver epoxy is that it doesn't have a lot of strength and can't be replied on to generate a physically strong joint...
The silver epoxy has a film thickness dependent conduction behavior (due to the percolation behavior of the conductive particles and the viscosity of the epoxy).  The resistivity levels are reduced as the adhesive film thickness increases. Conversely, when the thickness is reduced significantly, a significant increase in resistivity is observed coupled with a significant increase in the slope of the resistivity-thickness curve.  On the other hand, as the thickness increases, the strength decreases.  So, getting it right is an art  :)

I have experience working with silver epoxy. As stated will be using several thin layers. allowed to totally cure between layers and then using the copper/metal epoxy overcoat. Will also be using a thin / fine copper mesh, applied as the 1st layer, next to the copper outer skin, to back it up.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/25/2015 03:37 PM
I do believe what we see in the 2nd image to the left of the Red RF feed may not be an impedance matching system but instead an arm that extends inside the Flight Thruster such that Shawyer can fine tune the antenna position. It appears to have a small arm / crank on the left end and the ability to slide in and out.

Eagle Eyes!

Yes, I agree, that's exactly what it appears to be. Would the crank move the launcher/antenna up and down - or side to side?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 03:47 PM
I do believe what we see in the 2nd image to the left of the Red RF feed may not be an impedance matching system but instead an arm that extends inside the Flight Thruster such that Shawyer can fine tune the antenna position. It appears to have a small arm / crank on the left end and the ability to slide in and out.

Eagle Eyes!

Yes, I agree, that's exactly what it appears to be. Would the crank move the launcher/antenna up and down - or side to side?

If there is a TM mode excitation antenna inside, someone said he used a T antenna, it would need to be aligned exactly to the cavity central axis, ie in exact alignment with a line between the end plate centres.

Depending on how he physically built this, would allow the desired movement he needed to get physical alignment of the internal excitation antenna to the frustum effective central axis.

As I will have only 100W to work with, will need every bit of tuning, tweaking and small incremental gains to get enough thrust to have a VERY healthy signal to noise ratio.

It may also need to be located at the frustum diameter where the guide wavelength is at the effective cavity guide wavelength, so to get 1/4 wave resonance from the centre of the antenna to each end plate or 1/2 wave resonance overall.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/25/2015 04:01 PM
Regarding antenna placement. In Meep, exciting the electric modes, I have good success achieving resonance when I place the antenna one-half wavelength from the end of the cavity (cylindrical cavity). What does the theory say about antenna placement to achieve resonance?

Note that this works well even when I change the drive frequency as long as the frequency is near the resonant frequency of a mode of the cavity. Meep excites with a noisy (Gaussian) source and zeros in on the resonance frequency without to much fiddling this way.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/25/2015 04:03 PM

If space time is being bent, and the bend is symmetrical, the non-thrusting (smaller) end plate should have an opposite attracting (pulling) force rather than a repulsive (pushing) force.

Could these forces be detected by Iulian in his test setup. So, rather than hang the drive on the scales, place the drive on the floor, then hang a weight on the scale that lies as close to the end plate as possible. Then repeat for the other plate.


That's an interesting experiment in that it is independent of the cavity errors.  If we look at something like Eq. 14 in Marco's paper, we might expect to see nothing for a perfectly conducting cavity.  Copper isn't perfect, so there may be an effect due to dielectric (or magnetic) leakage.  In any event, an independent weight measurement would be much less noisy, I would think.  (so more sensitive, as required)

How could you visualize the Em waveforms of a thrust mode outside the cavity if somehow and still keeping the cavity shape and TM or TE resonate mode? (yes I know the copper is reflecting or absorbing the EM waves) Does this make sense in how I said it? Like a virtual wave? I'd try it without asking, but just don't have the software.
 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 04:06 PM
Regarding antenna placement. In Meep, exciting the electric modes, I have good success achieving resonance when I place the antenna one-half wavelength from the end of the cavity (cylindrical cavity). What does the theory say about antenna placement to achieve resonance?

Note that this works well even when I change the drive frequency as long as the frequency is near the resonant frequency of a mode of the cavity. Meep excites with a noisy (Gaussian) source and zeros in on the resonance frequency without to much fiddling this way.

I feel as the cavity needs to have resonance with the effective cavity guide wavelength, the use of a T antenna may be good, with the centre of the antenna placed at the frustum diameter which generates the same guide wavelength as the numerically integrated overall guide wavelength.

Then as the changing frustum diameter shortens or lengthens the guide wavelengths as they near the end plates, the antenna will sense cavity resonance, even thought the guide wavelength at each end will not be the guide wavelength present at the central point of the T antenna.

Trust this makes sense.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/25/2015 04:13 PM

If space time is being bent, and the bend is symmetrical, the non-thrusting (smaller) end plate should have an opposite attracting (pulling) force rather than a repulsive (pushing) force.

Could these forces be detected by Iulian in his test setup. So, rather than hang the drive on the scales, place the drive on the floor, then hang a weight on the scale that lies as close to the end plate as possible. Then repeat for the other plate.


That's an interesting experiment in that it is independent of the cavity errors.  If we look at something like Eq. 14 in Marco's paper, we might expect to see nothing for a perfectly conducting cavity.  Copper isn't perfect, so there may be an effect due to dielectric (or magnetic) leakage.  In any event, an independent weight measurement would be much less noisy, I would think.  (so more sensitive, as required)

Don't waste your time please. This is 10^22+ orders of magnitude too small to measure a gravitational effect on normal matter. Again, the gravitational field acts on matter across a very wide bandwidth of frequencies. The majority of mass is inside the nucleus, so the majority of the interaction with gravity is happening in that bandwidth. The effect we have here is only mimicking those effects over a very narrow bandwidth "inside" the waveguide. Outside, all you'll measure is heat.

Todd
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/25/2015 04:20 PM
Has anyone ever tried to detect radiation at any frequency outside of the cavity? Theoretically I think there should be none but has that been verified?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 04:31 PM
Has anyone ever tried to detect radiation at any frequency outside of the cavity? Theoretically I think there should be none but has that been verified?

You mean ionising radiation?

There is plenty of EMC as Shawyer commented on during the Demonstrator rotary test:
http://emdrive.com/dynamictests.html

Quote
The field strengths within the thruster equate to a power level of 17MW. Signal leakage causes EMC effects within the fixed video camera. This leads to the apparent vertical movements.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/25/2015 04:32 PM

If space time is being bent, and the bend is symmetrical, the non-thrusting (smaller) end plate should have an opposite attracting (pulling) force rather than a repulsive (pushing) force.

Could these forces be detected by Iulian in his test setup. So, rather than hang the drive on the scales, place the drive on the floor, then hang a weight on the scale that lies as close to the end plate as possible. Then repeat for the other plate.


That's an interesting experiment in that it is independent of the cavity errors.  If we look at something like Eq. 14 in Marco's paper, we might expect to see nothing for a perfectly conducting cavity.  Copper isn't perfect, so there may be an effect due to dielectric (or magnetic) leakage.  In any event, an independent weight measurement would be much less noisy, I would think.  (so more sensitive, as required)

How could you visualize the Em waveforms of a thrust mode outside the cavity if somehow and still keeping the cavity shape and TM or TE resonate mode? (yes I know the copper is reflecting or absorbing the EM waves) Does this make sense in how I said it? Like a virtual wave? I'd try it without asking, but just don't have the software.
 

You can look at the radiation patterns for a dielectric cavity of the same dimensions.  The losses in a copper cavity are principally from the resistance in the walls, but there are also some radiative losses (albeit very small, but not calculated at this point) from any cavity w/ a finite Q.  In the limit the Q gets very low and you have effectively a photon rocket.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/25/2015 04:48 PM
...All good points. I believe she is trying to facilitate using Maxwell's equations by imagining there are particles inside the volume. Maxwell's equations are difficult, this is a crutch. Where she is making her mistake is that there actually are charged particles inside the volume, (besides air) they are not imaginary, they are confined to within the skin effect depth of the metal. The skin effect is inside the volume of integration for the Divergences, and it contains both positive and negative charges. Typically, we ignore the force acting on the lattice ions, since their mass is so much greater than the electrons, but they are there and they do scatter, vibrate and transfer momentum from the field to the frustum.

Unfortunately, she does not elaborate on the actual expressions of E and H, that would depend on the geometry, attenuation, phase, etc... she leaves that to the results table of her FEA. But the force equation she ends up with is still the correct equation. Its correctness, as always, depends on the accuracy of what you plug-in for E and H at the boundary, and the duty cycle of the power consumption. Therefore, if you know what to plug in, it's only a "minor" issue in her example and explanation, not in the actual FEA which is supposedly a realistic simulation of a brass cavity.

Let's agree that real charged particles (with the EM Drive in a vacuum) are confined within the skin depth of the material. 

At 2.45 GHz frequency, the skin depth is readily calculated to be only 1.3*10-6 m. 

Compare this dimension with the height of the cavity which she gives as 2*10-1 m.

Therefore the height of the cavity is 160,000 times larger than the skin depth.

This ratio (160,000 times) shows why she considers the case of having a fluid of charged particles inside the cavity.

If it takes a finite element mesh of  69,549 nodes to model the cavity, to also model the skin would take 160,000 times finer mesh (smaller finite elements) to model similar electromagnetic field variation.  The finite element matrix goes like the square, so to invert the finite element matrix becomes an overwhelming job, even for a supercomputer (that she does not indicate as having used).

Moreover, she would need to specify the constitutive model she would use to model the skin effect (which she does not specify).

No, the indications are that to simultaneously model the skin effect with a Finite Element model is not practically feasible and that's why she doesn't describe it.

On the contrary, she states that she effectively did not model the skin effect with a finite element discretization, see page 9, section 3.2 "Thrust calculation" where she states:

Quote
with air as filling medium and electric wall boundary condition,

So what she did was, instead of modeling the skin effect with a finite element discretization, she simply modeled it as a boundary condition.

Since we know that one cannot get a net force (averaged over an integer number of time periods) without charged particles in the cavity medium, or without a constitutive model describing absorption in the skin, either we have to take her at her word that she modeled the medium in the cavity as having charged particles, or that she used a separate equation to model the skin effect (not a finite element discretization of the skin effect).

Therefore, she must have some undisclosed free parameters, either modeling virtual charged particles in the medium in the cavity (air) or in her formula for the skin effect.

Then her model is not that different from Dr. White's, as she has "not nailed the problem" until one is satisfied that her free parameters can be substantiated by independent physical data. 

Quote from: John Von Neumann
With four parameters I can fit an elephant, and with five I can make him wiggle his trunk.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zen-in on 05/25/2015 05:04 PM

Plan is to laser cut all the pieces from 0.5mm thick copper sheet. Have found a company that can do a proper roll of the frustum so the side joint is a butt joint. Same company can form the spherical end plates.

1) UL certified Copper epoxy will be used to join the 2 end flanges to the frustum and then cover the butt joint.
http://www.supergluecorp.com/super-glue/epoxies/copper-bond

Does anyone have an opinion on this joining method?


I would go for an old fashioned soldering.  Why introduce another unknown variables caused by the glue?

BTW. I wanted to say Hi to the whole community. I've been around for a while reading, now I'll try to throw my 5 cents from the point of view of a mechatronic engineer... well if I have something useful to say.

Thanks for the comment.

I have concerns about the frustum warping when using soldering. Have built stuff before using thin copper plate, know it moves and the final soldered positions may not be the unsoldered position.

As I see it, making sure the 2 end plates are highly parallel and joined to the frustum at the same angle ensures the highest Q I can get. Using a cold assembly method should ensure the money I'm paying for laser cutting, to ensure everything is at the right angles to each other, will pay dividends.

It's very easy to cut thin copper with metal shears.   Inside curves are a little tricky but a straight edge linoleum knife works well.   Epoxy may work for joining the pieces if the joints are tab joints.   Otherwise handling and heating will make it come apart.   Conductive epoxy is an insulator at microwave frequencies, due to the skin effect.  Silver fill Copper or Brass is one option.   This product has a thin layer of Sterling Silver bonded to Copper or Brass sheet.  The Silver layer is thicker than plating.   I don't know who makes it now and you would really want fine Silver (999) anyway because Sterling Silver has a lower conductivity than Copper.   Silver plating, to achieve better RF skin layer conductivity than Copper is not easy to do.   If you really wanted to optimize this em-drive cavity you could use 24 K Gold plated fine Silver sheet.   Gold is actually a better conductor at microwave frequencies when skin effects, etc are considered; although fine Silver is the best room temperature conductor at DC and MF.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 05:17 PM

Plan is to laser cut all the pieces from 0.5mm thick copper sheet. Have found a company that can do a proper roll of the frustum so the side joint is a butt joint. Same company can form the spherical end plates.

1) UL certified Copper epoxy will be used to join the 2 end flanges to the frustum and then cover the butt joint.
http://www.supergluecorp.com/super-glue/epoxies/copper-bond

Does anyone have an opinion on this joining method?


I would go for an old fashioned soldering.  Why introduce another unknown variables caused by the glue?

BTW. I wanted to say Hi to the whole community. I've been around for a while reading, now I'll try to throw my 5 cents from the point of view of a mechatronic engineer... well if I have something useful to say.

Thanks for the comment.

I have concerns about the frustum warping when using soldering. Have built stuff before using thin copper plate, know it moves and the final soldered positions may not be the unsoldered position.

As I see it, making sure the 2 end plates are highly parallel and joined to the frustum at the same angle ensures the highest Q I can get. Using a cold assembly method should ensure the money I'm paying for laser cutting, to ensure everything is at the right angles to each other, will pay dividends.

It's very easy to cut thin copper with metal shears.   Inside curves are a little tricky but a straight edge linoleum knife works well.   Epoxy may work for joining the pieces if the joints are tab joints.   Otherwise handling and heating will make it come apart.   Conductive epoxy is an insulator at RF frequencies, due to the skin effect.  Silver fill Copper or Brass is one option.   This product has a thin layer of Sterling Silver bonded to Copper or Brass sheet.  The Silver layer is thicker than plating.   I don't know who makes it now and you would really want fine Silver (999) anyway because Sterling Silver has a lower conductivity than Copper.   Silver plating, to achieve better RF skin layer conductivity than Copper is not easy to do.   If you really wanted to optimize this em-drive cavity you could use 24 K Gold plated Fine Silver sheet.   Gold is actually a better conductor at RF frequencies when skin effects, etc are considered; although Fine Silver is the best room temperature conductor at DC and low RF frequencies.

Thanks for the information.

My use of silver epoxy will be restricted to external frustum surfaces. If any gets inside, it will be removed.  The Copper Epoxy overcoat is UL rated to not come apart in plumbing and fire sprinkler applications:

http://www.supergluecorp.com/super-glue/epoxies/copper-bond

Quote
Safe and easy to use Copper-Bond® is UL listed for joining copper tube used in fire sprinkler systems and NSF approved for hot and cold water systems.

As my max power input is 100W, I feel the joint temperatures should be well with-in the UL rating.

There will also be alum supporters as per the 1st Experimental device, so will get additional surface area to radiate heat. All this will be inside a sealed Faraday Cage as Shawyer used.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 05:22 PM
The Copper Bond Epoxy may be of use to other replicators. Data here:
http://www.supergluecorp.com/super-glue/epoxies/copper-bond

Data sheet attached.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/25/2015 05:32 PM
...All good points. I believe she is trying to facilitate using Maxwell's equations by imagining there are particles inside the volume. Maxwell's equations are difficult, this is a crutch. Where she is making her mistake is that there actually are charged particles inside the volume, (besides air) they are not imaginary, they are confined to within the skin effect depth of the metal. ...

Let's agree that real charged particles (with the EM Drive in a vacuum) are confined within the skin depth of the material. 

(...)
No, the indications are that to simultaneously model the skin effect with a Finite Element model is not practically feasible and that's why she doesn't describe it.

On the contrary, she states that she effectively did not model the skin effect with a finite element discretization, see page 9, section 3.2 "Thrust calculation" where she states:

Quote
with air as filling medium and electric wall boundary condition,

So what she did was, instead of modeling the skin effect with a finite element discretization, she simply modeled it as a boundary condition.

Since we know that one cannot get a net force (averaged over an integer number of time periods) without charged particles in the cavity medium, or without a constitutive model describing absorption in the skin, either we have to take her at her word that she modeled the medium in the cavity as having charged particles, or that she used a separate equation to model the skin effect (not a finite element discretization of the skin effect).

Therefore, she must have some undisclosed free parameters, either modeling virtual charged particles in the medium in the cavity (air) or in her formula for the skin effect.
(...)

Correct, she has undisclosed free parameters! That is what I meant when I said she did not elaborate on her expressions for E and H. Technically, she does not need to model the skin effect in her FEA. She simply needs to express her E and H amplitudes with an exponential attenuation factor.

If I go by Zeng and Fan, then;

E(r, theta, phi) = A(theta, phi)*exp[jk*r]

jk*r => -a*r - jb*r,

Where, "a" is the attenuation factor. Her amplitude would then include a factor of exp[-2a] in the pressure term. The attenuation factor is a free parameter that depends on the geometry and material, which she does not disclose. However, her "equation", is correct IFF you plug in the correct expressions for E and H at the boundary.

I wrote a paper back in 2007 about propellant-less propulsion, for an "Acceleration to Voltage Transducer". In it, I show how accelerating Mass with the Lorentz force is equivalent to an Inductive load, which must be offset by a capacitive load (charge) to do physical work, by correcting the power factor to unity. I showed that in a closed system where the divergence is zero and where momentum is stored, you can still transfer momentum from the field to the particles in a cleaver way, to produce thrust. There are many similarities to what we are discussing now. My work has a flaw however. I found it is impossible to store any significant amount of charge and have it not polarize everything around it, negating most of the effect. I end up with F1 - F2 ~ 0, except for losses and leakage flux, and the amount of charge required becomes enormous. (links) Though I have never built one and tested it.

https://www.dropbox.com/s/pddq48tlxtj5f7s/AccelerationTransducer.pdf?dl=0
https://www.dropbox.com/s/lmie4j7oo7lkqyo/Propellant-less%20Propulsionx3.pdf?dl=0



Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/25/2015 05:46 PM
...Correct, she has undisclosed free parameters! That is what I meant when I said she did not elaborate on her expressions for E and H. Technically, she does not need to model the skin effect in her FEA. She simply needs to express her E and H amplitudes with an exponential attenuation factor...
Well it is always a pleasure to discuss things with you.  Besides your universally recognized gift for explaining things in simpler terms that people can relate to, discussions with you lead to deeper levels of common understanding.

And now with that preamble, until Prof. Yang discloses her constitutive model for the skin effect, and we can independently ascertain whether her free parameter(s) are based on known material properties, is her model really to be preferred to models like Dr. McCulloch's or Notsosureofit's that also model the thrust, but with a minimum of free parameters ?  (Neither McCulloch's or Notsosureofit's models need such extra free parameters: they don't need the attenuation factor).
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: demofsky on 05/25/2015 05:50 PM
...I also think I found a (minor?) error in the 2013 paper. In my estimation, equations 4 and 6 are correct. Where I disagree is that her premise is that there are charged particles in the volume, and then on equations 7 and 8, she removes the particle momentum density and the energy density of the field, for no apparent reason and then IMO, she abruptly ends the section....
Can you please elaborate why youthink this is, maybe, just a (minor) error by Prof. Yang and her co-authors?

(And by the way, I am looking at the 2010 paper, not the 2013 paper, in my comments below)

They write (2010 paper, translation page 4,  original page 28)

http://www.emdrive.com/NWPU2010translation.pdf
Quote
If the microwave electromagnetic field consists of charge particles, due to the
electromagnetic force, the charge particles can travel within the electromagnetic
field, so the charge particles can acquire energy and momentum from the
electromagnetic field. This indicates that electromagnetic field have energy and
momentum.

The microwave electromagnetic field inside the cavity is composed of photons (at microwave frequencies), which as we all know, have no charge whatsoever.  So the microwave electromagnetic field does not consist of charge particles (unless one considers the virtual particles of the QV or one considers ionized air).  This is the difference between Greg Egan's equations http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html, who finds no net thrust force, since he doesn't consider this term at all.

If there are any charges and currents, they are only present in the copper metal (translation says "brass"), and not inside the empty microwave cavity.  This seems to me a major issue, and not a minor point.



The original 2010 paper in Chinese (http://www.emdrive.com/NWPU2010paper.pdf) says (my translation)

Quote
The microwave electromagnetic field of charged particles , if present , due to the electromagnetic force 

The "if present" seems to have been translated to "if it consists of".  Either way, "If present" or "if it consists of" is a big if.   We have to understand whether this condition is met, and if so, what are these charged particles.

Are the authors considering charged particles to be present in the empty cavity?

In essence are the authors effectively considering virtual charged particles like the QV of Dr. White ?

Or are the authors considering having ionized air inside the cavity ?
  (one example:  http://www.jpier.org/PIERM/pierm26/20.12101201.pdf  )

Hm.  As has been noted many times both Sawyer and Yangs experiments are ran at atmospheric pressure and are furthermore (as far as anyone can tell) well sealed.

So, in an excess of caution desiring to make sure we explicitly cover all the bases here, I have to ask the following question:

Are these ion wind devices?  (Masquerading as exotic physics machines...)

Intuitively, if there is an ionic wind in these devices then I certainly can believe there will be measurable effects from the wind hammering (relatively speaking) the frustum wall.

One defence for this hypotheses is the difference in measured effects between the Yang and Sawyer devices and the Eagleworks vacuum tests.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: ThinkerX on 05/25/2015 06:12 PM
Quote
One defense for this hypotheses is the difference in measured effects between the Yang and Sawyer devices and the Eagleworks vacuum tests.

To me, this is a really crucial bit of info.  If these devices loose this much performance in a vacuum, then are they really all that superior to a photon rocket?  Or could they be some bizarre version of Bae's bouncing laser scheme, which increases photonic thrust on the order of 5000 times? (except with one spacecraft instead of two?)




Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 06:16 PM
The Frank Davies mode analysis (attached) did a really good covering most of the frustum TEmnp and TMmnp modes.

TE013 is missing and may be of interest as the E field intensity at the small end may be very large.

Can anybody supply the E and H field analysis as NASA did but for the missing TE013 mode? It will be worth your time as I have significant new information regarding the Flight Thruster. It operated in TE013 mode.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Fugudaddy on 05/25/2015 06:23 PM
Shawyer opinion: He found something. If he knew what, this group would have figured out his math by now. He thinks he has, Boeing seems to think he has. I think there's 'something else' happening. *shrug*

Science question, straightforward.
Thermodynamic/aerodynamic effects- shouldn't they be neutralized if the thing is tested in a 'right to left' then 'left to right' configuration?

Science question- more complex.

I don't math; but I get the language of symbology.  This is about gravity and those effects that EW seemed to measure.

So let's call 'p' a point of gravity in our hypothetical fustrum that is strong enough to create a 'gravitational lensing' effect. So waves can't pass over/through p, but have to pass around it.

Waves bouncing around in general (coming into the space) will pass through and carry on the other side, balancing out the effects of p.

Waves coming straight back up the narrowing (or expanding, whichever) are perturbed enough by p so that by the time the wave 'comes together' on the other side of p, the size of the wave has changed from where it was, so its energy (or something) has to change to match its new size, right?

If that is the case, would reducing 'p' enough so that the waves are disturbed, but not necessarily 'broken' by p be enough to introduce this energy change and if so, would that be enough to help explain where that extra 'push' is coming from?

There's no pushing off of QV or anything, since waves that pass around galaxies do so without any magic hoohoo. But the difference there is that's in space, so there's no 'changing' the wave dimensions since the 'sides' of the space those waves are moving through is, in effect, infinite.

It's a vague handwaving understanding, from the thought of the waves in the fustrum somehow managing to create a mini black hole for a moment, what would happen then?

Thanks. :)

(just as an aside- would *love* to see more DiY results. Some measurable result is far more important than proving the most effective result possible, imho).
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/25/2015 06:25 PM
The Frank Davies mode analysis (attached) did a really good covering most of the frustum TEmnp and TMmnp modes.

TE013 is missing and may be of interest as the E field intensity at the small end may be very large.

Can anybody supply the E and H field analysis as NASA did but for the missing TE013 mode? It will be worth your time.
There are an infinite (yes infinite) number of natural frequencies in the real world, that are missing from the calculations because they have a natural frequency beyond the range covered in the eigenvalue analysis (which goes to 2.5 GHz).

In order to accurately model the higher natural frequencies, a finer discretization mesh is needed.  To obtain all the infinite number of natural frequencies one would need an infinite number of finite elements.  The matrix that needs to be inverted to get the eigenvalues grows with the square of the finite element mesh, so it quickly becomes overwhelming.

cylTE013 as well as cylTE01p with p equal or greater than 3 have a frequency higher than 2.5 GHz for the NASA Eagleworks geometry.

There are a number of other mode shapes next to cylTE013.  Is there any particular reason why you are interested in cylTE013 ?


I write cylTEmnp because these are mode shapes close to the equivalent mode shape in a cylinder, but there are other mode shapes in the truncated cone that have no close analog in the cylinder.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 06:30 PM
Is there any particular reason why you are interested in TE013 ?

More breadcrumbs have appeared :)

Was told by Roger Shawyer to use TE013 mode to design my Flight Thruster replication. He said otherwise I was on the right track. Appears he is monitoring this forum.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: mwvp on 05/25/2015 07:04 PM

1) UL certified Copper epoxy will be used to join the 2 end flanges to the frustum and then cover the butt joint.
http://www.supergluecorp.com/super-glue/epoxies/copper-bond

Does anyone have an opinion on this joining method?


I would solder or plate, as was recommended. The glue, from the MSDS, is 90-100% epoxy. Surely is non-conductive, not to mention that because of the skin effect even conductive glue particles could be resistive and a place for Q attenuation and arcing.

I wonder if Nasa was limited to 30W because of arcing in the vacuum chamber? That what killed their RF amp? A low mode high-Q cavity may high problems around sharp points and edges.

Didn't one of the photos closeups of the inside of Shawyers frustrum show a link-coupling near the inside of the cavity wall? It was a dozen or so pages back in the 2nd thread.

I'm half-ready to build one of these. I'll have a look at Meep and simulating it, then buzzing out some flimsy hastily-built cavities to figure out the feedpoint.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zen-in on 05/25/2015 07:06 PM

...

Quote
Safe and easy to use Copper-Bond® is UL listed for joining copper tube used in fire sprinkler systems and NSF approved for hot and cold water systems.

As my max power input is 100W, I feel the joint temperatures should be well with-in the UL rating.

There will also be alum supporters as per the 1st Experimental device, so will get additional surface area to radiate heat. All this will be inside a sealed Faraday Cage as Shawyer used.

The UL rating is immaterial to your application.  Plumbing fittings are inherently much stronger than all other types because one tube is inside the other.   Since you will be using the epoxy like putty the advertised strength will not be there.   One option to consider is to assemble the parts and hold it together with light gauge iron wire before soldering it.   Wrapping the wire around everything will hold it in place when it is soldered.   The Copper doesn't expand very much when lead solder is used.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 07:18 PM

1) UL certified Copper epoxy will be used to join the 2 end flanges to the frustum and then cover the butt joint.
http://www.supergluecorp.com/super-glue/epoxies/copper-bond

Does anyone have an opinion on this joining method?


I would solder or plate, as was recommended. The glue, from the MSDS, is 90-100% epoxy. Surely is non-conductive, not to mention that because of the skin effect even conductive glue particles could be resistive and a place for Q attenuation and arcing.

I wonder if Nasa was limited to 30W because of arcing in the vacuum chamber? That what killed their RF amp? A low mode high-Q cavity may high problems around sharp points and edges.

Didn't one of the photos closeups of the inside of Shawyers frustrum show a link-coupling near the inside of the cavity wall? It was a dozen or so pages back in the 2nd thread.

I'm half-ready to build one of these. I'll have a look at Meep and simulating it, then buzzing out some flimsy hastily-built cavities to figure out the feedpoint.

Thanks for the comments.

Will be putting a thin & fine copper mesh over the joints. Then 2 thin layers of silver epoxy to electrically bond the copper mesh to the copper frustum. Next use the copper epoxy as an overlayer to give added structural strength. No epoxy will be inside the cavity.

I'm paying for laser cut accuracy so the ends are parallel to each other by very small fraction of a degree. I fell this is needed to get the highest Q to make up for my low 100W power.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 07:21 PM

...

Quote
Safe and easy to use Copper-Bond® is UL listed for joining copper tube used in fire sprinkler systems and NSF approved for hot and cold water systems.

As my max power input is 100W, I feel the joint temperatures should be well with-in the UL rating.

There will also be alum supporters as per the 1st Experimental device, so will get additional surface area to radiate heat. All this will be inside a sealed Faraday Cage as Shawyer used.

The UL rating is immaterial to your application.  Plumbing fittings are inherently much stronger than all other types because one tube is inside the other.   Since you will be using the epoxy like putty the advertised strength will not be there.   One option to consider is to assemble the parts and hold it together with light gauge iron wire before soldering it.   Wrapping the wire around everything will hold it in place when it is soldered.   The Copper doesn't expand very much when lead solder is used.

Thanks.  Good points. Will think on your and others suggestions.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/25/2015 07:29 PM
@WarpTech raises a very good point.  Any system which provides propellant-less acceleration should also work as an accelerometer.   Photon resonators are already used as accelerometers. (and by extension, gravity wave detectors)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/25/2015 07:39 PM
Is there any particular reason why you are interested in TE013 ?

More breadcrumbs have appeared :)

Was told by Roger Shawyer to use TE013 mode to design my Flight Thruster replication. He said otherwise I was on the right track. Appears he is monitoring this forum.

                            Truncated cone    Truncated cone    Truncated cone      Approximation using
Mode Shape          Rodal Exact          NASA COMSOL    Difference             Cylindrical Cavity  (GHz)
                            solution (GHz)      solution (GHz)     NASA vs. exact     Diameter=Mean (*)
                           
TE011                  1.78972              1.77048             1.08%                   1.79324

TE012                  2.20244              2.1794               1.05%                   2.12264

TE013                  2.65493              ?                         ?                           2.57980

Note:  Rodal Truncated Cone exact solution has spherical ends, COMSOL FEA and Cylindrical Soltution have flat ends.

(*) Cylindrical Solution http://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity
using Diameter = (1/2)(bigDiameter  + smallDiameter )



Geometrical dimensions: 

bigDiameter = 11.00 inches used by Rodal, 11.01 inches used by Jerry Vera for his COMSOL FEA solution
smallDiameter = 6.25 inches;
axialLength = 9 inches;

spherical coordinate r1 = 0.300789 meters

spherical coordinate r2 = 0.529389 meters
 
cone half angle = 14.7827 degrees

speed of light in medium = 299792458 meter/second (Vacuum)

(http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/CavityShape.gif)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/25/2015 08:21 PM
@WarpTech raises a very good point.  Any system which provides propellant-less acceleration should also work as an accelerometer.   Photon resonators are already used as accelerometers. (and by extension, gravity wave detectors)

Exactly, that's where Dr. McCulloch's work comes in, though I'm not well versed in his model yet. Accelerating a cavity full of energy, oscillating in modes will cause a doppler shift to propagate through. Here, that doppler shift is being caused by energy lost to the cavity.

Momentum is being input to the cavity via the microwaves, dp_in/dt, and is stored in the oscillating modes, Q*dp_in/dt. The rate of dissipation of that momentum, -dp/dt = F, will determine the forces on each surface. If that rate is not simply a constant of the metal, but a variable of the geometry, there will be asymmetrical forces, velocities and doppler shifts. Agreed?

Todd


Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: X_RaY on 05/25/2015 08:30 PM
Is there any particular reason why you are interested in TE013 ?

More breadcrumbs have appeared :)

Was told by Roger Shawyer to use TE013 mode to design my Flight Thruster replication. He said otherwise I was on the right track. Appears he is monitoring this forum.


Mode Shape          Rodal Exact solution (GHz)       NASA COMSOL FEA solution (GHz)  Difference

TE011                  1.78972                                 1.77048                                       1.08%

TE012                  2.20244                                  2.1794                                        1.05%

TE013                  2.65493                                  ?                                                  ?

Note:  Rodal solution has spherical ends, COMSOL FEA has flat ends.

Geometrical dimensions: 

bigDiameter = 11.00 inches used by Rodal, 11.01 inches used by Jerry Vera for his COMSOL FEA solution
smallDiameter = 6.25 inches;
axialLength = 9 inches;

spherical coordinate r1 = 0.300789 meters

spherical coordinate r2 = 0.529389 meters
 
cone half angle = 14.7827 degrees

speed of light in medium = 299792458 meter/second (Vacuum)

(http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/CavityShape.gif)

Hello i am new in this forum. Based on my own simple model(flat end plates) the frequency has to be approximately 2.52GHz.
I hope this is helpfull :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: R.W. Keyes on 05/25/2015 08:35 PM
There's much on this subject I don't understand. I feel like if I had another twenty years to study this, I might be able to have a better grasp.

But there are some things I might be able to address, because of some of the practical experience I've had in RF. If worried about the shift away from resonance due to thermal expansion in a high-Q frustum, would a useful remedy be to choose a longer wavelength, and larger frustum, so that the deformation is a small portion of a wavelength? Now, I understand that there may be other reasons to want to operate at a shorter wavelength (more power).

I have noted that Shawyer uses a silicon carbide structural base, and then plates this with a superconductor. Silicon carbide is very stiff in regards to temperature changes (note: now it can also be 3D-printed). At what wavelengths is it sufficiently stiff at a superconducting temperature?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/25/2015 09:01 PM
..If worried about the shift away from resonance due to thermal expansion in a high-Q frustum, would a useful remedy be to choose a longer wavelength, and larger frustum, so that the deformation is a small portion of a wavelength? Now, I understand that there may be other reasons to want to operate at a shorter wavelength (more power)...

For a simple uniaxial case, for a plate (plane stress state):

Thermal Strain = coefficientOfThermalExpansion *(delta T)
                       = (delta L) / L  (if free to change in length)

For a given change in temperature (delta T), the longer L, the greater the change in length due to thermal expansion if unrestrained.  Thermal strain is independent of length.



Thermal Stress = (Thermal Strain) *ModulusOfElasticity /(1-PoissonRatio2
                       = ( ModulusOfElasticity /(1-PoissonRatio2)  ) *coefficientOfThermalExpansion *(delta T)

(if plate is restrained, and prevented from thermal expansion)

For a given change in temperature (delta T), the thermal strain and stress are the same, governed by material properties (coefficient of thermal expansion, modulus of elasticity and Poisson's ratio). 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/25/2015 10:35 PM
There's much on this subject I don't understand. I feel like if I had another twenty years to study this, I might be able to have a better grasp.

But there are some things I might be able to address, because of some of the practical experience I've had in RF. If worried about the shift away from resonance due to thermal expansion in a high-Q frustum, would a useful remedy be to choose a longer wavelength, and larger frustum, so that the deformation is a small portion of a wavelength? Now, I understand that there may be other reasons to want to operate at a shorter wavelength (more power).

I have noted that Shawyer uses a silicon carbide structural base, and then plates this with a superconductor. Silicon carbide is very stiff in regards to temperature changes (note: now it can also be 3D-printed). At what wavelengths is it sufficiently stiff at a superconducting temperature?

Shawyers solution for the high Q Flight Thruster, which I'm following,  is to use a variable frequency Rf generator that samples the cavity E field and varies the frequency to stay in resonance. Then thermal changes to generated thrust should be minimised.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/25/2015 11:49 PM
I think this paper may be of some interest for those not so familiar with tensor equations.

https://www.dropbox.com/s/wxzz2nf3dlqvibc/Puthoff_EnergyDensity_0904.1617.pdf?dl=0

"Abstract: It is well understood that various alternatives are available within EM theory for the definitions of energy density, momentum transfer, EM stress-energy tensor, and so forth. Although the various options are all compatible with the basic equations of electrodynamics (e.g., Maxwell’s equations, Lorentz force law, gauge invariance), nonetheless certain alternative formulations lend themselves to being seen as preferable to others with regard to the transparency of their application to physical problems of interest. Here we argue for the transparency of an option based on use of the EM potentials alone."

I like Puthoff's method of explaining things, he is very clear and doesn't overwhelm me with too much information.

So, remember yesterday when I said the Divergence of S and of n*T were zero? Turns out, that's only true if the energy is already stored in the cavity and the microwave source is turned "off". As long as the source of microwaves is turned on, there is a non-zero divergence corresponding to the input power flux. So I take it back, the divergence is not zero with the microwave motor running.

Todd
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 12:32 AM
How the Maser was invented also is useful to get us to think about the nature of the EM Drive in more conventional ways.  There are three keys to the Maser's operation:

1) Find a gas which energetically emits at the same frequency at which we want to operate the cavity.  In the first Maser, they used the Ammonia molecule because after WWII microwave technology had been developed for Radar, and it was noted that the ammonia molecule happens to strongly emit at 23.79 GHz ( https://en.wikipedia.org/wiki/Ammonia#Structure ).

2) Segregate the population of molecules in the gas so that the stimulated emission overrides absorption.  (In the first maser this was done by physically segregating the lower energy levels of the ammonia gas).

3) Intensify the action by using a resonant  cavity of high Q.


Scientists after WWII took advantage of the already known fact that ammonia gas molecules react to a non-uniform electric field in ways that depend on the energy levels of the ammonia gas molecules.  This offered a way to segregate the high-energy molecules from the low energy molecules.  In the first Maser ammonia gas was made to flow through a cylinder where an electric field draws the low-energy molecules away to the inner surfaces of the cylinder while the high-energy molecules of ammonia flow through, into a cavity.  With a large excess of high-energy molecules the cavity is set for Maser action.  A 24 GHz photon entering this energy-laden gas soon encounters  a high energy molecule and knocks out another 24 GHz photon , which results in amplification.  However, without further aid this process is not intense enough to build up usable strength.
It was crucial to success that the inventor of the Maser understood there would have to be a way to intensify the action.  The inventor realized that this amplification could be obtained by harnessing the phenomenon of resonance of a cavity: high Q.  The cavity was designed to resonate with standing waves at the same frequency of 24 GHz at which the ammonia gas energetically emits.  In the reverberant space of the cavity the photons are kept rocketing back and forth through the energy-loaded gas so as to build a vigorous sustained oscillation.  The 24 GHz vibration entering the cavity is amplified 100 times in power. 

Hm.  As has been noted many times both Sawyer and Yangs experiments are ran at atmospheric pressure and are furthermore (as far as anyone can tell) well sealed...One defence for this hypotheses is the difference in measured effects between the Yang and Sawyer devices and the Eagleworks vacuum tests.

To me, this is a really crucial bit of info.  If these devices loose this much performance in a vacuum, then are they really all that superior to a photon rocket?  ...

It is indeed noteworthy that although Shawyer has been working on the EM Drive for decades, that no experiment in a vacuum has been reported by Mr. Shawyer.

Prof. Yang has been working on EM Drive experiments since prior to 2010, yet we are in 2015 and we have not yet heard of her performing experiments in a vacuum.

It took NASA Eagleworks less than a year to perform an EM Drive experiment in a vacuum and the results showed significantly less thrust/InputPower than the one measured in air.

So it definitely has to be considered whether the gas molecules inside the EM Drive may not indeed be undergoing segregation between high-energy and low-energy, and whether the gas molecules may be playing a role (beyond the obvious one of air convection, gas exiting the EM Drive under higher pressure than ambient, buoyancy due to higher temperature, etc.)

In this regard it is interesting that Prof. Yang asks the reader to consider the case of a gas of charged particles inside the EM Drive as a means to understand how it is able to accelerate without breaking the law of Conservation of Momentum.

As Todd has been writing, for the EM Drive there appears to be the need of a balance between high Q resonance and absorption.  If there is a gas (air) inside the cavity that has charged particles (some ionization produced within the Microwave cavity), and whose molecules can be segregated by the electric field, then so much the better for this process of amplification (almost like in the Maser).

http://b.gatech.edu/1cX7sXj

http://www.mike-willis.com/Tutorial/gases.htm


http://www.jpier.org/PIERB/pierb15/09.09041706.pdf

http://www1.lsbu.ac.uk/water/microwave_water.html

(http://www.propagation.gatech.edu/ECE6390/project/Fall2012/Team09/Team9GeoSatTech_website_FINAL/SatCom%20website/images/GaseousAttenuation.png)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: ThinkerX on 05/26/2015 01:01 AM
Quote
In this regard it is interesting that Prof. Yang want the reader to consider the case of a gas of charged particles inside the EM Drive as a means to understand how it is able to accelerate without breaking the law of Conservation of Momentum.

As Todd has been writing, for the EM Drive there appears to be the need of a balance between high Q resonance and absorption.  If there is a gas (air) inside the cavity that has charged particles (some ionization produced within the Microwave cavity), and whose molecules can be segregated by the electric field, then so much the better for this process of amplification (just like in the Maser).

So...if I am following this correctly, then even for a spacecraft version, you'd still want the frustum to be pressurized...though possibly with something other than nitrogen/oxygen.  That seems doable, unless the device's continuous operation degrades the atmosphere over time.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/26/2015 01:40 AM
When it all starts becoming too much to comprehend, and a headache begins to develop, the best remedy is to dip one's quantum oar into the quantum vacuum and pull on it a little.  :P
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheUberOverLord on 05/26/2015 01:50 AM
Would like to thank everyone for such diversified input on this since I have been silently following this topic since "thread one". Personally, I have a deep respect for each persons current thoughts on this.

While I do realize that this is "Way out there!".

Is it possible that whatever reactions/movements AKA "Thrust" could be being caused by the inverse of what's being done to slow down atoms using frequencies of light Atomic telescope brings atoms to standstill (http://arstechnica.com/science/2015/05/atomic-telescope-brings-atoms-to-standstill/) by using microwave frequencies to excite virtual particles, dark matter or even dark energy?

I ask because this also seems to at least potentially show a classical to quantum transition taking place in some form.

Unless it turns out that all prior experiments have had the same non discovered faults/flaws inside and outside a vacuum.

Don
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: rfmwguy on 05/26/2015 02:09 AM
Would like to thank everyone for such diversified input on this since I have been silently following this topic since "thread one". Personally, I have a deep respect for each persons current thoughts on this.

While I do realize that this is "Way out there!".

Is it possible that whatever reactions/movements AKA "Thrust" could be being caused by the inverse of what's being done to slow down atoms using frequencies of light Atomic telescope brings atoms to standstill (http://arstechnica.com/science/2015/05/atomic-telescope-brings-atoms-to-standstill/) by using microwave frequencies to excite virtual particles, dark matter or even dark energy?

I ask because this also seems to at least potentially show a classical to quantum transition taking place in some form.

Unless it turns out that all prior experiments have had the same non discovered faults/flaws inside and outside a vacuum.

Don
Good question don...thread 1 reader myself; got courage to post late in thread 2. All data by shawyer and others leaves open questions. Myself, I believe we are seeing a legit discovery, not yet fully explained. Not sure if its thrust, attraction or  a surfing a space-time wave. We live in warped space time, a gravity well...do these experiments overide our warped space or do they create a new one? This is what fascinates me and why I follow this topic and braintrusts here. Stay tuned!  PS wasn't reading thread for 2 days and now feel 1.4 lightyears behind  ;)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/26/2015 02:16 AM
Would like to thank everyone for such diversified input on this since I have been silently following this topic since "thread one". Personally, I have a deep respect for each persons current thoughts on this.

While I do realize that this is "Way out there!".

Is it possible that whatever reactions/movements AKA "Thrust" could be being caused by the inverse of what's being done to slow down atoms using frequencies of light Atomic telescope brings atoms to standstill (http://arstechnica.com/science/2015/05/atomic-telescope-brings-atoms-to-standstill/) by using microwave frequencies to excite virtual particles, dark matter or even dark energy?

I ask because this also seems to at least potentially show a classical to quantum transition taking place in some form.

Unless it turns out that all prior experiments have had the same non discovered faults/flaws inside and outside a vacuum.

Don
Welcome to the thread ... And what would we put the probibility of all test systems and/or cavities having the same flaws/faults?

Regarding the ionization of gasses within the cavity, what is the high frequency at where it becomes difficult to construct a resonant cavity using known materials and construction techniques? Three-D printing comes to mind as a construction technique but at some size pressurizing small cavities must become difficult.

I wonder if the guys making the 25 GHz beauty will make it gas filled?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/26/2015 03:34 AM
@WarpTech raises a very good point.  Any system which provides propellant-less acceleration should also work as an accelerometer.   Photon resonators are already used as accelerometers. (and by extension, gravity wave detectors)

Exactly, that's where Dr. McCulloch's work comes in, though I'm not well versed in his model yet. Accelerating a cavity full of energy, oscillating in modes will cause a doppler shift to propagate through. Here, that doppler shift is being caused by energy lost to the cavity.

Momentum is being input to the cavity via the microwaves, dp_in/dt, and is stored in the oscillating modes, Q*dp_in/dt. The rate of dissipation of that momentum, -dp/dt = F, will determine the forces on each surface. If that rate is not simply a constant of the metal, but a variable of the geometry, there will be asymmetrical forces, velocities and doppler shifts. Agreed?

Todd

One thing I had almost forgotten about that Accelerometer because it's been so long since I've worked on it. IF it were possible to create a device that, when simply placed in an accelerated reference frame, it would output a voltage from which constant power could be extracted. It implies (deltaMass?) that if it were sitting on the floor in my garage, I could extract infinite energy from the gravitational field, which is an accelerated reference frame relative to the Accelerometer sitting on the floor.

What happens instead is, the accelerometer becomes polarized and the charge density on the "charged objects" is no l longer evenly distributed. It cannot output more than the amount of power required to polarize it. I can input energy to depolarize it, and then extract it as it polarizes again, but I can't get free energy from it.

Therefore, any propellant-less propulsion device, must have some means of becoming depolarized. In the case of the frustum, stored energy is lost to heat as well as thrust, and this eventually depolarizes it so it can be re-charged and thrust again. Once again, it can only work in a pulsed mode, when power is ramping up and down quickly.

Todd
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/26/2015 04:05 AM
Since I have no model for how this thing is supposed to work, I can't speculate as to its inner workings.
What I can do (and have done here) is treat it as a single system and describe its gestalt dynamics.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zellerium on 05/26/2015 04:08 AM
I did some more investigation into this paper by Yang Juan published  2014-01-09:
http://wulixb.iphy.ac.cn/EN/abstract/abstract60316.shtml

I couldn't find a translated version so I put it through google translate. Unfortunately that didn't work very well, but I was able to fix it up and figure out what they did (see attachment).

My takeaway:
This paper did not include any thrust measurement or high power sources. They simply injected a mW signal into their apparatus to figure out how to tune it to maximize Q. They tested many different aperture dimensions and used two tuning screws to minimize reflectance. The tuning screws seem like an easy way to augment the input signal, perhaps someone could help me understand how that works. It appears they use the aperture to minimize return loss and improve the Q by narrowing the bandwidth. [They still maintain that a higher Q factor in the frustum is more desirable. ]

They also investigated the effect of temperature by using an external heat source. They determined that heating up the small plate has the greatest impact on quality factor; an increase of 17.4 C shifts the resonant frequency by 1 MHz. The effect of heating the other plate and sidewalls does not have as great of an impact, but still changes things. They heated these plates from the outside so as to not disturb the signal, so I imagine heating from the inside would produce a much greater shift.

I'm still unsure where the 'matched' system comes into play (first picture). Maybe this was their initial design and was reformed to be the tuning mechanism with the screws and aperture. I didn't see any comment as to which one was better.

I realize that a lot of info was lost in translation, so I'm going to ask my friend help translate some of it.

I think Yang is getting much better thrust values because she isn't sending the energy through coaxial cables and antennas as done by Shawyer. Maybe this allows the whole system to resonate together whereas the antennas and cables have some associated impedance and attenuation that increase losses.

So now I'm thinking we should try to create a very thick cavity, we could forge one using aluminum pretty easily and clean it up with a CNC. [backyard casting: url:youtube.com/watch?v=sGr_XoFTKmc]

Take a look at my sloppy translated version and see what you can make of it.

Kurt
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Supergravity on 05/26/2015 04:11 AM
Can someone possibly get me up to speed on the theoretical work done on this so far, if any? It seems from what I'm reading, most of the apparent groundbreaking work seems to be on the experimental side. Have these scientists come up with a better explanation than "quantum-vacuum-plasma-phonon-hocus-pocus" that actually conserves momentum as well being consistent with the weak and strong energy conditions in GR?

As far as I know, the only thing slightly controversial even to this day in classical electrodynamics is angular momentum conservation. It is conserved, of course, but there are certain contrived circumstances that could apparently break conservation of L in CED. But, for linear momentum, there are no thought experiments one can think up that violates it conservation.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zen-in on 05/26/2015 05:05 AM
I did some more investigation into this paper by Yang Juan published  2014-01-09:
http://wulixb.iphy.ac.cn/EN/abstract/abstract60316.shtml
...

 It appears they use the aperture to minimize return loss and improve the Q by narrowing the bandwidth. [They still maintain that a higher Q factor in the frustum is more desirable. ]

Good work on improving the translation.  You are partly right.  The aperture is used to isolate the load from the feed.    The forward wave gets through the aperture but the reflected wave, because it is out of phase can't.   To get a high Q the return loss has to be at a maximum.  A return loss of 1 dB is the same as reflection coefficient of .89 and a VSWR of  17.4.  At the other end a return loss of 40 dB is the same as a reflection coefficient of .01 and a VSWR of 1.02.   A high return loss means less RF is being reflected from the cavity so the Q is higher.

...
I think Yang is getting much better thrust values because she isn't sending the energy through coaxial cables and antennas as done by Shawyer. Maybe this allows the whole system to resonate together whereas the antennas and cables have some associated impedance and attenuation that increase losses.

While I don't believe any em-drive produces thrust I do entertain a <1% possibility because Shawyer and Yang did something different.    Stardrive mentioned their PA got damaged and I noted they used a large in-line attenuator at one point.  That indicates a high SWR.  So instead of confining the RF to the cavity it was getting reflected back.   Coax can absorb a lot of RF power.   Waveguide on the other hand is much less lossy and can be configured to minimize reflected power.

...

So now I'm thinking we should try to create a very thick cavity, we could forge one using aluminum pretty easily and clean it up with a CNC. [backyard casting: url:youtube.com/watch?v=sGr_XoFTKmc]

You should stick with Copper sheet.   Cast Aluminum, even if it is pure Al will not have as good conductivity due to microcracks, slag inclusions, bubbles, etc.   Aluminum is not forged because it cracks when heated and hit with hammers.   A fine Silver cavity would have a higher Q  than Copper, and would be much easier to form. Since there is not as much markup on Silver the cost would be about 5X the cost of Copper.  A fusion weld can be done to close the cone with no discontinuity at the seam.    For Copper you can get the cone crimped at the ends and use Be-Cu finger stock to bridge the flat ends (instead of solder) and adjustable slug with the cone.  That would make it easy to disassemble.   Later, when all is said and done it will make a good museum display.
...

Kurt
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/26/2015 06:02 AM
I've misplaced the Wiki/FAQ thread on EmDrive
Could I have that link please?
And shouldn't it be easy to find? (I couldn't, though I tried).
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: R.W. Keyes on 05/26/2015 07:17 AM
I believe more experiments, much of them performed competently and honestly, have happened without results being publicly reported. We know that Dr. Yang has retreated from publicity because of potential military applications of her work. It can be assumed that Roger Shawyer has a specific interest in keeping certain information confidential, so that he can make good economic benefit from his work. It is also known the Boeing has an EMdrive interest, and as they do, then it is likely that Lockheed-Martin has some project at their "skunkworks" as well. With Chinese and American defense organizations involved, I imagine that Russia, and perhaps India, and European interests, also have programs related to the EMdrive and similar developments. Because of the significant military uses of the EMDrive, in addition to the commercial advantages, who can blame these organizations for being tight-lipped? It is also conceivable that these organizations, being in great competition with each other, may attempt to sabotage each other's work by the means of false data releases. Such subterfuge has happened in the past, in other areas of science and engineering,  and I see no reason why it EMdrive research should be exempt from such actions.

In light of this, the lack of reported results from tests done in vacuum should not make one presume that such tests haven't been done. I've considered the idea that USAF's latest X-37B mission may have some EMdrive experiment on board.

But please realize that most of this is semi-informed speculation, and I don't claim to know specifics. I merely think it's likely that much is occurring sub-rosa.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zellerium on 05/26/2015 07:18 AM

You should stick with Copper sheet.   Cast Aluminum, even if it is pure Al will not have as good conductivity due to microcracks, slag inclusions, bubbles, etc.   Aluminum is not forged because it cracks when heated and hit with hammers.   A fine Silver cavity would have a higher Q  than Copper, and would be much easier to form. Since there is not as much markup on Silver the cost would be about 5X the cost of Copper.  A fusion weld can be done to close the cone with no discontinuity at the seam.    For Copper you can get the cone crimped at the ends and use Be-Cu finger stock to bridge the flat ends (instead of solder) and adjustable slug with the cone.  That would make it easy to disassemble.   Later, when all is said and done it will make a good museum display.

Thanks for the advice.

I think you misunderstood, we would cast the aluminum in a dye and then use a computer controlled mill to shave of the excess. I'd imagine a 1 inch thick frustum that is well polished on the inside would have a better Q factor than a 20 mil copper sheet after several tests because it will be able to absorb much more heat without deforming. NWPU doesn't publish their dimensions, but the pictures seem to indicate a very thick cavity. The flight thruster also seems quite thick.
I think we are probably going to end up trying both.

Why don't you believe the EM Drive is producing a thrust?
Seems to me most of the spurious effects have been eliminated, or at least minimized. The results are certainly inconsistent, but so are the experiments. Whatever the cause of this anomalous thrust, it has definitely stumped a lot of great minds for quite a while...

Kurt
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Karlman on 05/26/2015 07:31 AM
Wiki/FAQ Thread

http://emdrive.echothis.com/Main_Page (http://emdrive.echothis.com/Main_Page)

Created by ???

Can this get added to the first post maybe?
---
Edit Removed attribution to R.W. Keyes (my apologies.. was the only name I could find associated with the wiki).
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: R.W. Keyes on 05/26/2015 07:44 AM
Wiki/FAQ Thread

http://emdrive.echothis.com/Main_Page (http://emdrive.echothis.com/Main_Page)

Created by R.W._Keyes (http://emdrive.echothis.com/User:R.W._Keyes)

Can this get added to the first post maybe?

While I am in favor of this Wiki, it is unfair to attribute it to me as I did not create it.

That being said, I encourage all of the more advanced members of this forum to contribute, discuss, and correct issues on the wiki so that it can serve as an introduction to the topics at hand, and also show where the theoretical disagreement exist, with references to back them up.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/26/2015 07:54 AM

You should stick with Copper sheet.   Cast Aluminum, even if it is pure Al will not have as good conductivity due to microcracks, slag inclusions, bubbles, etc.   Aluminum is not forged because it cracks when heated and hit with hammers.   A fine Silver cavity would have a higher Q  than Copper, and would be much easier to form. Since there is not as much markup on Silver the cost would be about 5X the cost of Copper.  A fusion weld can be done to close the cone with no discontinuity at the seam.    For Copper you can get the cone crimped at the ends and use Be-Cu finger stock to bridge the flat ends (instead of solder) and adjustable slug with the cone.  That would make it easy to disassemble.   Later, when all is said and done it will make a good museum display.

Thanks for the advice.

I think you misunderstood, we would cast the aluminum in a dye and then use a computer controlled mill to shave of the excess. I'd imagine a 1 inch thick frustum that is well polished on the inside would have a better Q factor than a 20 mil copper sheet after several tests because it will be able to absorb much more heat without deforming. NWPU doesn't publish their dimensions, but the pictures seem to indicate a very thick cavity. The flight thruster also seems quite thick.
I think we are probably going to end up trying both.

Why don't you believe the EM Drive is producing a thrust?
Seems to me most of the spurious effects have been eliminated, or at least minimized. The results are certainly inconsistent, but so are the experiments. Whatever the cause of this anomalous thrust, it has definitely stumped a lot of great minds for quite a while...

Kurt

It's not an easy subject for people who haven't already made up their minds on one side of the debate or the other to know where to pitch their scepticism..
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/26/2015 09:50 AM
Thought experiment: Can people please supply thoughts/feedback on the following

If a suitable length of fiber optic cable was acquired and wound around a hollow cylinder that was just bigger than the diameter of a cavity, such that the fiber cylinder fitted over top of the cavity.

The fiber is hooked up to a laser light source.

Either a second laser light source (or a half silvered mirror is used to split the original beam into two paths) such that both paths end their journey at a single visual screen.

Could we achieve interferometry with a setup like this and therefore a means to test for the potential presence of G waves emitting from an active cavity?.

Realising that both the second beam and the visual display unit would need to be some distance away from the cavity such that any effect on the primary beam is potentially noticeable (eg emerging G waves will be at atmospheric C)

 OR
Could a coiled length of fiber optic attached to one end of the cavity achieve the same sort of result?

There is a type of fiber made of some sort of plastic? material that is used in server rooms for short haul data....  might be useful?

This is what White and his team did with a rectangular box. The effect is there as they observed satellite frequencies of the input laser beam. I have shown this in my paper too. When you apply the idea to the computation of the thrust, for the current geometries and input powers, the gravitational effect appears to be too minuscule to account for the measured one.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: supryin on 05/26/2015 11:29 AM
I believe more experiments, much of them performed competently and honestly, have happened without results being publicly reported. We know that Dr. Yang has retreated from publicity because of potential military applications of her work. It can be assumed that Roger Shawyer has a specific interest in keeping certain information confidential, so that he can make good economic benefit from his work. It is also known the Boeing has an EMdrive interest, and as they do, then it is likely that Lockheed-Martin has some project at their "skunkworks" as well. With Chinese and American defense organizations involved, I imagine that Russia, and perhaps India, and European interests, also have programs related to the EMdrive and similar developments. Because of the significant military uses of the EMDrive, in addition to the commercial advantages, who can blame these organizations for being tight-lipped? It is also conceivable that these organizations, being in great competition with each other, may attempt to sabotage each other's work by the means of false data releases. Such subterfuge has happened in the past, in other areas of science and engineering,  and I see no reason why it EMdrive research should be exempt from such actions.

In light of this, the lack of reported results from tests done in vacuum should not make one presume that such tests haven't been done. I've considered the idea that USAF's latest X-37B mission may have some EMdrive experiment on board.

But please realize that most of this is semi-informed speculation, and I don't claim to know specifics. I merely think it's likely that much is occurring sub-rosa.

I would like to thank everybody for the contribution to this thread! I have been following it for quite a while now.

Do you remember the video of the EmDrive test published by some russian guy on YouTube?
It was published in this thread as well - unfortunately I was unable to find the particular post.
Anyway, meanwhile this video got deleted from the YouTube.
And also from all other social networks which repost usually such videos.
Might support the above theory.

 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 11:47 AM
...Do you remember the video of the EmDrive test published by some russian guy on YouTube?
It was published in this thread as well - unfortunately I was unable to find the particular post.
Anyway, meanwhile this video got deleted from the YouTube.
And also from all other social networks which repost usually such videos.
Might support the above theory.
I remember a video from Russia in a vertical set-up.  The video I remember involved a waveguide having one end closed and the other end open.  The author wrote in Russian that he thought that Shawyer was wrong to use a close cavity because nothing comes out of a completely close cavity and therefore the author of the video thought it made much more sense to have an open waveguide.  The device he tested looked like the shape of a bottle having a big opening, made of metal.  It behaved as one would expect: with the close end of the waveguide being pushed forward, and the open end of the waveguide trailing behind.  I don't recall something unusual in the video, as it is known that open microwave waveguides will have propulsion as photons leave the waveguide: it is essentially a photon rocket with photons at microwave frequencies.  It satisfies conservation of momentum.  It is an inefficient method of space propulsion.

The Russian author also had written words to the effect that he didn't have much resources to conduct a better test.

If this is the same video you are referring to, I suggest that the video may have been deleted from YouTube as the author may have been made aware that an open waveguide is supposed to behave this way, and therefore it was not noteworthy and not directly related to Shawyer's EM Drive invention which is a completely closed cavity.

I looked for the video that I recalled on YouTube, searching for "EM Drive Russia" and nothing shows up.

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 01:47 PM

You should stick with Copper sheet.   Cast Aluminum, even if it is pure Al will not have as good conductivity due to microcracks, slag inclusions, bubbles, etc.   Aluminum is not forged because it cracks when heated and hit with hammers.   A fine Silver cavity would have a higher Q  than Copper, and would be much easier to form. Since there is not as much markup on Silver the cost would be about 5X the cost of Copper.  A fusion weld can be done to close the cone with no discontinuity at the seam.    For Copper you can get the cone crimped at the ends and use Be-Cu finger stock to bridge the flat ends (instead of solder) and adjustable slug with the cone.  That would make it easy to disassemble.   Later, when all is said and done it will make a good museum display.

Thanks for the advice.

I think you misunderstood, we would cast the aluminum in a dye and then use a computer controlled mill to shave of the excess. I'd imagine a 1 inch thick frustum that is well polished on the inside would have a better Q factor than a 20 mil copper sheet after several tests because it will be able to absorb much more heat without deforming. NWPU doesn't publish their dimensions, but the pictures seem to indicate a very thick cavity. The flight thruster also seems quite thick.
I think we are probably going to end up trying both.

Why don't you believe the EM Drive is producing a thrust?
Seems to me most of the spurious effects have been eliminated, or at least minimized. The results are certainly inconsistent, but so are the experiments. Whatever the cause of this anomalous thrust, it has definitely stumped a lot of great minds for quite a while...

Kurt
When assessing the pros and cons of a thicker or thinner EM Drive, please consider that a thick (where thick means larger (thickness/characteristicLength) ratio) metal EM Drive accomplishes (at least) these purposes to minimize thermal effects:

1) It drastically minimizes thermal bending, and distortion

2) it practically eliminates the possibility of thermal buckling
https://www.researchgate.net/publication/268804028_NASA%27S_MICROWAVE_PROPELLANT-LESS_THRUSTER_ANOMALOUS_RESULTS_CONSIDERATION_OF_A_THERMO-MECHANICAL_EFFECT

3) It provides a heat sink for heat to be absorbed.  It greatly increases the Fourier time: the time parameter associated with heat diffusion and hence it serves to minimize thermal effects.

4) It alleviates the possibility of thermal convection currents being set up by heated external surfaces of the EM Drive (as the exterior surface of a thick metal EM Drive will reach a lower temperature at a given time from initial turn on of the power)

Thin sheets contribute to thermal distortion and thermal bending and greatly enhance the possibility that the EM Drive goes out of resonance as the thermal effect distorts the cavity.

The thickness enters the thermal deformation and the Fourier time as higher powers of the dimensionless ratio (thickness/length) so thickness has a great effect.

A thin sheet EM Drive, on the other hand is an invitation to endless thermal effects: distortion, thermal expansion, thermal bending, thermal buckling, hot spots, enhancement of thermal convection currents, etc. etc.

EDIT: My understanding of the reason why NASA used thin sheet for the EM Drive is that they were very constrained by the allowed weight they could have on their horizontal torsional pendulum.   

One alternative: think smaller dimensions, which allows for thicker thickness/CharacteristicLength ratio
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: frobnicat on 05/26/2015 02:13 PM
...
I remember a video from Russia in a vertical set-up.  The video I remember involved a waveguide having one end closed and the other end open. 
...
I don't recall something unusual in the video, as it is known that open microwave waveguides will have propulsion as photons leave the waveguide: it is essentially a photon rocket with photons at microwave frequencies.  It satisfies conservation of momentum.  It is an inefficient method of space propulsion.

1kW photon thrust makes for only about 3µN, unless it is efficiently recycled (like photonic laser thruster by BAE) which I doubt is the case, the setup looked open enough to leak microwaves copiously around. If this is the video in question, I recall the scale registering a gram force or so, from those values I doubt this was due to just EM beamed force...

Quote
The Russian author also had written words to the effect that he didn't have much resources to conduct a better test.

It's always easy to criticize from afar, but looks to me a heat induced convection flow would very likely be the cause of pushing a plate above such a heated chimney (http://en.wikipedia.org/wiki/Stack_effect). Demo would have been much more convincing by showing that placing a thin cardboard (or otherwise microwave transparent thin membrane) between the pipe and the weighed plate above (to block the convective air flow) would not alter the readings, if not dropping them to 0.

Quote
If this is the same video you are referring to, I suggest that the video may have been deleted from YouTube as the author may have been made aware that an open waveguide is supposed to behave this way, and therefore it was not noteworthy and not directly related to Shawyer's EM Drive invention which is a completely closed cavity.

Though not directly related to EM drives closed cavities, it would be very noteworthy for a DIYer to really "beam" a gram force at a distance of a few decimetres (?) with only 1kW. Bae is not much beyond that with PLT at optical wavelength (but with better long range prospect obviously).
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 02:20 PM
...1kW photon thrust makes for only about 3µN, unless it is efficiently recycled (like photonic laser thruster by BAE) which I doubt is the case, the setup looked open enough to leak microwaves copiously around. If this is the video in question, I recall the scale registering a gram force or so, from those values I doubt this was due to just EM beamed force...
I didn't recall the measured force and I couldn't find the video again to be able to check it.  If he measured 1 gram, that's thousands of times better performance than a photon rocket, and as you said, it would be very noteworthy (if the measurement was not  an artifact). 

So perhaps he pulled the video out of YouTube once he realized that what he was measuring was an artifact.

I hope he didn't get hurt during the experiment.

Thanks for pointing this out.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/26/2015 02:55 PM
Maybe I missed some information due to my delay on following these threads. What are the characteristics of the cavities used by NASA? I mean the physical dimensions, the input power (I know this is around tenth of W) and the relative dielectric constant of the material used as a dielectric (HDPE). Could the latter be similar to conjugate polymers or some ceramic material with this value ranging to some 10^5?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 02:58 PM
Maybe I missed some information due to my delay on following these threads. What are the characteristics of the cavities used by NASA? I mean the physical dimensions, the input power (I know this is around tenth of W) and the relative dielectric constant of the material used as a dielectric (HDPE). Could the latter be similar to conjugate polymers or some ceramic material with this value ranging to some 10^5?

Please find the physical dimensions of NASA's truncated cone (they have only one) here:  http://forum.nasaspaceflight.com/index.php?topic=37642.msg1379668#msg1379668




experimental results here:

Table 2, page 18,  (original document)
http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf



EM Drive experimental results compilation:

http://emdrive.echothis.com/Experimental_Results



Dielectric used in NASA's truncated cone experimental results was HDPE only:

http://forum.nasaspaceflight.com/index.php?topic=36313.msg1378069#msg1378069



Document showing dielectric used for NASA's truncated cone:  http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=634621

(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=636341;image)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Mulletron on 05/26/2015 03:18 PM
http://dlib.eastview.com/browse/doc/12472752

Russians......

Well this is in the public domain so it means that if these thrusters truly work, the race among nations has been going on for a while. There is no way the Western world didn't notice this  :)

I remember reading other stuff about reports of Russian satellites making anomalous maneuvers. Moving satellites around costs precious propellant and is generally avoided if it isn't absolutely necessary....unless.

http://www.iflscience.com/space/mysterious-satellite-sparks-concerns-russia-has-developed-space-weapon
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/26/2015 03:19 PM
Maybe I missed some information due to my delay on following these threads. What are the characteristics of the cavities used by NASA? I mean the physical dimensions, the input power (I know this is around tenth of W) and the relative dielectric constant of the material used as a dielectric (HDPE). Could the latter be similar to conjugate polymers or some ceramic material with this value ranging to some 10^5?

Please find the physical dimensions of NASA's truncated cone (they have only one) here: 

...

Thanks a lot!
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: saucyjack on 05/26/2015 03:25 PM
While I am in favor of this Wiki, it is unfair to attribute it to me as I did not create it.

That being said, I encourage all of the more advanced members of this forum to contribute, discuss, and correct issues on the wiki so that it can serve as an introduction to the topics at hand, and also show where the theoretical disagreement exist, with references to back them up.

@RW - not sure why you were attributed as the author on that page, I'll try to fix that.

@Chris B - Good idea to add the wiki link to the first post of this thread.  Is that possible?  Thanks to @streppa, you can now also access it at the somewhat more memorable URL: http://emdrive.wiki

As always we appreciate any and all help on the wiki.  Particularly in light of today's discussion about the missing video from the Russian experimenter, please add any relevant external links to the wiki that you come across; you can upload any files as well.  If you have other suggestions for how to make the wiki better please PM me.

-Rolf
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/26/2015 03:39 PM
Thought experiment: Can people please supply thoughts/feedback on the following


This is what White and his team did with a rectangular box. The effect is there as they observed satellite frequencies of the input laser beam. I have shown this in my paper too. When you apply the idea to the computation of the thrust, for the current geometries and input powers, the gravitational effect appears to be too minuscule to account for the measured one.
I know Dr. white did it for a rectangular box, did you do it for the EM Frustum cavity and take into account the geometry of the cavity? And does the gravitational effect scale  through the Frustum as the geometry of the cavity changes?
Thanks... back to reading. Shell
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 03:43 PM
[email protected] B - Good idea to add the wiki link to the first post of this thread.  Is that possible?  ...
Link to EM Drive wiki is now added to the initial post on this thread. :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/26/2015 03:47 PM
Thought experiment: Can people please supply thoughts/feedback on the following


This is what White and his team did with a rectangular box. The effect is there as they observed satellite frequencies of the input laser beam. I have shown this in my paper too. When you apply the idea to the computation of the thrust, for the current geometries and input powers, the gravitational effect appears to be too minuscule to account for the measured one.
I know Dr. white did it for a rectangular box, did you do it for the EM Frustum cavity and take into account the geometry of the cavity? And does the gravitational effect scale  through the Frustum as the geometry of the cavity changes?
Thanks... back to reading. Shell

The problem here is that, for gravity, all scales as G/c^4, something like 10^-43. Geometry, dielectric and all that help to mitigate by several orders of magnitude such a small number but I cannot see how to recover a thrust of the order of tenths of micronewton.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 03:49 PM
Thought experiment: Can people please supply thoughts/feedback on the following


This is what White and his team did with a rectangular box. The effect is there as they observed satellite frequencies of the input laser beam. I have shown this in my paper too. When you apply the idea to the computation of the thrust, for the current geometries and input powers, the gravitational effect appears to be too minuscule to account for the measured one.
I know Dr. white did it for a rectangular box, did you do it for the EM Frustum cavity and take into account the geometry of the cavity? And does the gravitational effect scale  through the Frustum as the geometry of the cavity changes?
Thanks... back to reading. Shell

The problem here is that, for gravity, all scales as G/c^4, something like 10^-43. Geometry, dielectric and all that help to mitigate by several orders of magnitude such a small number but I cannot see how to recover a thrust of the order of tenths of micronewton.
For whatever it's worth, I tried also on my own using Mathematica , based on your paper, and I arrived at your same above conclusions
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: VAXHeadroom on 05/26/2015 03:57 PM
How the Maser was invented also is useful to get us to think about the nature of the EM Drive in more conventional ways.  There are three keys to the Maser's operation:
...
It was crucial to success that the inventor of the Maser understood there would have to be a way to intensify the action.  The inventor realized that this amplification could be obtained by harnessing the phenomenon of resonance of a cavity: high Q.  The cavity was designed to resonate with standing waves at the same frequency of 24 GHz at which the ammonia gas energetically emits.  In the reverberant space of the cavity the photons are kept rocketing back and forth through the energy-loaded gas so as to build a vigorous sustained oscillation.  The 24 GHz vibration entering the cavity is amplified 100 times in power. 

Hm.  As has been noted many times both Sawyer and Yangs experiments are ran at atmospheric pressure and are furthermore (as far as anyone can tell) well sealed...One defence for this hypotheses is the difference in measured effects between the Yang and Sawyer devices and the Eagleworks vacuum tests.

To me, this is a really crucial bit of info.  If these devices loose this much performance in a vacuum, then are they really all that superior to a photon rocket?  ...

It is indeed noteworthy that although Shawyer has been working on the EM Drive for decades, that no experiment in a vacuum has been reported by Mr. Shawyer.

Prof. Yang has been working on EM Drive experiments since prior to 2010, yet we are in 2015 and we have not yet heard of her performing experiments in a vacuum.

It took NASA Eagleworks less than a year to perform an EM Drive experiment in a vacuum and the results showed significantly less thrust/InputPower than the one measured in air.

So it definitely has to be considered whether the gas molecules inside the EM Drive may not indeed be undergoing segregation between high-energy and low-energy, and whether the gas molecules may be playing a role (beyond the obvious one of air convection, gas exiting the EM Drive under higher pressure than ambient, buoyancy due to higher temperature, etc.)
...
http://b.gatech.edu/1cX7sXj
http://www.mike-willis.com/Tutorial/gases.htm
http://www.jpier.org/PIERB/pierb15/09.09041706.pdf
http://www1.lsbu.ac.uk/water/microwave_water.html

(http://www.propagation.gatech.edu/ECE6390/project/Fall2012/Team09/Team9GeoSatTech_website_FINAL/SatCom%20website/images/GaseousAttenuation.png)

I really think this is a critical insight.  The microwave frequencies being used are specifically tailored to heat water (as everybody is basically using a home microwave oven emitter) - this may indeed be a water molecule amplified maser.  The humidity at time of testing in the various locations should be measured and considered as a data point in the measured thrust.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/26/2015 03:57 PM

For whatever it's worth, I tried also on my own using Mathematica , based on your paper, and I arrived at your same above conclusions

Indeed, general relativity yields a too small contribution and so, one can conclude that whatever approach one uses to recover the third principle just fails. If there will be a confirmation of this effect it will be really interesting to find a theoretical account for it. Personally, I am unconvinced.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: supryin on 05/26/2015 04:04 PM
...1kW photon thrust makes for only about 3µN, unless it is efficiently recycled (like photonic laser thruster by BAE) which I doubt is the case, the setup looked open enough to leak microwaves copiously around. If this is the video in question, I recall the scale registering a gram force or so, from those values I doubt this was due to just EM beamed force...
I didn't recall the measured force and I couldn't find the video again to be able to check it.  If he measured 1 gram, that's thousands of times better performance than a photon rocket, and as you said, it would be very noteworthy (if the measurement was not  an artifact). 

So perhaps he pulled the video out of YouTube once he realized that what he was measuring was an artifact.

I hope he didn't get hurt during the experiment.

Thanks for pointing this out.

Yes, this is the video I am talking about.
I am pretty sure the measured thrust in the video was about 1 gramm.
Probably you are right, the author saw an artefact and pulled the video. Thanks!
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/26/2015 04:09 PM
I really think this is a critical insight.  The microwave frequencies being used are specifically tailored to heat water (as everybody is basically using a home microwave oven emitter) - this may indeed be a water molecule amplified maser.  The humidity at time of testing in the various locations should be measured and considered as a data point in the measured thrust.

The Flight Thruster EM Drive Shawyer built for Boeing was a sealed unit and operates at 3.85GHz.
http://www.emdrive.com/flightprogramme.html

Have been told Boeing, in 2014, still had that unit.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 04:16 PM
I really think this is a critical insight.  The microwave frequencies being used are specifically tailored to heat water (as everybody is basically using a home microwave oven emitter) - this may indeed be a water molecule amplified maser.  The humidity at time of testing in the various locations should be measured and considered as a data point in the measured thrust.

The Flight Thruster EM Drive Shawyer built for Boeing was a sealed unit and operates at 3.85GHz.
http://www.emdrive.com/flightprogramme.html

The effect we are discussing will certainly take place in a sealed unit, if the gas inside the sealed cavity has the properties required for the effect to take place.  All that is required is for the gas inside the cavity to have these properties.  As per Prof. Yang's analysis in her 2010 paper.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/26/2015 04:17 PM
I wonder if "sealed" and "gas tight" are truly synonymous here. After all, there is an RF connector (at least)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/26/2015 04:26 PM
I wonder if "sealed" and "gas tight" are truly synonymous here. After all, there is an RF connector (at least)

I'll ask Shawyer.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/26/2015 04:32 PM

For whatever it's worth, I tried also on my own using Mathematica , based on your paper, and I arrived at your same above conclusions

Indeed, general relativity yields a too small contribution and so, one can conclude that whatever approach one uses to recover the third principle just fails. If there will be a confirmation of this effect it will be really interesting to find a theoretical account for it. Personally, I am unconvinced.
Honestly, I got the old pencil and eraser out and hacked my way through it and saw the same miniscule effect. I guess I needed verification. Thanks guys
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/26/2015 04:34 PM
Isn't there some conference set for mid-September where we might hear more one way or the other on this topic? Unfortunately for the life of me I've forgotten what it's called but, I'm sure Mr Shawyer did a presentation at it in 2013 if that helps identify it.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: VAXHeadroom on 05/26/2015 04:35 PM
I wonder if "sealed" and "gas tight" are truly synonymous here. After all, there is an RF connector (at least)

I'll ask Shawyer.

It wouldn't matter unless the test was done in a vacuum.  In ambient, the partial vapor pressure of the water wouldn't change (well...not much...heating MIGHT drive the moisture out somewhat).  This is a potential explanation of why there is a difference between tests at ambient pressure and those in a vacuum (if the device is NOT a pressure vessel).  Is it possible to get to White as well to ask about their test unit?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/26/2015 04:38 PM

For whatever it's worth, I tried also on my own using Mathematica , based on your paper, and I arrived at your same above conclusions

Indeed, general relativity yields a too small contribution and so, one can conclude that whatever approach one uses to recover the third principle just fails. If there will be a confirmation of this effect it will be really interesting to find a theoretical account for it. Personally, I am unconvinced.
Honestly, I got the old pencil and eraser out and hacked my way through it and saw the same miniscule effect. I guess I needed verification. Thanks guys

I hope tomorrow to post the latest version. With this, I will post also the corresponding Maple worksheet to tinkering about, if one likes. The effect is there but really too small. My guess is that more mundane explanations could be at work.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: birchoff on 05/26/2015 05:04 PM

For whatever it's worth, I tried also on my own using Mathematica , based on your paper, and I arrived at your same above conclusions

Indeed, general relativity yields a too small contribution and so, one can conclude that whatever approach one uses to recover the third principle just fails. If there will be a confirmation of this effect it will be really interesting to find a theoretical account for it. Personally, I am unconvinced.
Honestly, I got the old pencil and eraser out and hacked my way through it and saw the same miniscule effect. I guess I needed verification. Thanks guys

I hope tomorrow to post the latest version. With this, I will post also the corresponding Maple worksheet to tinkering about, if one likes. The effect is there but really too small. My guess is that more mundane explanations could be at work.

Are you saying that given the reasoning and calculations depicted in your paper. After doing some numerical analysis on the equations for the frustum configuration you are left with a really small effect orders of magnitude below that which has been reported so far by Shawyer, Yang, Cannae, EW, and jullian (The ukranian replicator, I am sure I probably butchered his name.)?

Just want to make sure I am understanding what your saying.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 05:08 PM
@WarpTech raises a very good point.  Any system which provides propellant-less acceleration should also work as an accelerometer.   Photon resonators are already used as accelerometers. (and by extension, gravity wave detectors)

Exactly, that's where Dr. McCulloch's work comes in, though I'm not well versed in his model yet. Accelerating a cavity full of energy, oscillating in modes will cause a doppler shift to propagate through. Here, that doppler shift is being caused by energy lost to the cavity.

Momentum is being input to the cavity via the microwaves, dp_in/dt, and is stored in the oscillating modes, Q*dp_in/dt. The rate of dissipation of that momentum, -dp/dt = F, will determine the forces on each surface. If that rate is not simply a constant of the metal, but a variable of the geometry, there will be asymmetrical forces, velocities and doppler shifts. Agreed?

Todd

One thing I had almost forgotten about that Accelerometer because it's been so long since I've worked on it. IF it were possible to create a device that, when simply placed in an accelerated reference frame, it would output a voltage from which constant power could be extracted. It implies (deltaMass?) that if it were sitting on the floor in my garage, I could extract infinite energy from the gravitational field, which is an accelerated reference frame relative to the Accelerometer sitting on the floor.

What happens instead is, the accelerometer becomes polarized and the charge density on the "charged objects" is no l longer evenly distributed. It cannot output more than the amount of power required to polarize it. I can input energy to depolarize it, and then extract it as it polarizes again, but I can't get free energy from it.

Therefore, any propellant-less propulsion device, must have some means of becoming depolarized. In the case of the frustum, stored energy is lost to heat as well as thrust, and this eventually depolarizes it so it can be re-charged and thrust again. Once again, it can only work in a pulsed mode, when power is ramping up and down quickly.

Todd
What do people think of the idea of driving the EM Drive with a TEmnp mode (transverse electric mode) such that the axial field is magnetic along the longitudinal direction.

Then the idea would be to make the EM Drive more of a "one-way" street (1-way directional waves rather than a 2-way street with standing waves) by placing tiny ferrite beads (magnets) along so as to minimize reflections (as done in the solid state ruby maser).

The number and size of the ferrite beads would control the fine tradeoff between Q resonance (needed for reverberation) and directionality (needed for thrust).

Perhaps this would allow the use of a cylindrical waveguide (instead of a truncated cone), one could control the amount of reflections by the size and number of ferrite beads along the axis.  (The size of the ferrite bead could be functionally graded such that the size of ferrite would monotonically increase in one direction, for example).

Also the use of a solid state material (such as the ruby used in the ruby maser) that can emit in a very wide range of microwave frequencies may allow much higher power to thrust force conversion.

Please notice as per the history of the Ruby Maser chart, that many Ruby Masers operated at similar microwave frequencies (2.4 GHz) as used for magnetrons for home cooking microwave ovens:
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/26/2015 05:11 PM

Are you saying that given the reasoning and calculations depicted in your paper. After doing some numerical analysis on the equations for the frustum configuration you are left with a really small effect orders of magnitude below that which has been reported so far by Shawyer, Yang, Cannae, EW, and jullian (The ukranian replicator, I am sure I probably butchered his name.)?

Just want to make sure I am understanding what your saying.

Yes, general relativity accounts for really a small part of the effect if this would be confirmed.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/26/2015 06:04 PM
I really think this is a critical insight.  The microwave frequencies being used are specifically tailored to heat water (as everybody is basically using a home microwave oven emitter) - this may indeed be a water molecule amplified maser.  The humidity at time of testing in the various locations should be measured and considered as a data point in the measured thrust.

The Flight Thruster EM Drive Shawyer built for Boeing was a sealed unit and operates at 3.85GHz.
http://www.emdrive.com/flightprogramme.html

The effect we are discussing will certainly take place in a sealed unit, if the gas inside the sealed cavity has the properties required for the effect to take place.  All that is required is for the gas inside the cavity to have these properties.  As per Prof. Yang's analysis in her 2010 paper.

So how would that work? Would the gas be ionized in a preferred direction such that a gas molecule accelerated in the positive direction (to pick a coordinate direction) would be less massive (by an electron or a few electrons) than the gas returning. The ionized gas reaches the base plate and on contact is deionized by accepting electrons from the metal then the less strongly ionized (neutralized) gas is accelerated (drifts) back to the other end finding the region within the cavity where ionization occurs with electrons given up to the cavity walls or other end. The cycle repeats.

The ionized gas molecule would be slightly less massive than the neutral molecule but due to much greater charge, would move at a much higher speed, hence impart more momentum to the end plate than would the slightly more massive (heavier) but much slower neutral molecule.  The electrons added to the base plate don't actually circulate back with momentum because it is the charge that travels at near light speed, the electrons in the cavity metal oscilate with low or zero average momentum.

Paul March reported that at one time Eagleworks did use a dielectric gasket separating the big end (maybe both ends) from the frustum body but they replaced the gasket with a metal/metal contact seal. I wonder why. Perhaps without electrical continuity it didn't work.

Edit Add: I just described a recirculating ion gun didn't I? How hot is this antenna anyway?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/26/2015 06:06 PM
Isn't there some conference set for mid-September where we might hear more one way or the other on this topic? Unfortunately for the life of me I've forgotten what it's called but, I'm sure Mr Shawyer did a presentation at it in 2013 if that helps identify it.

Shawyer did say he would be presenting a peer reviewed paper in 2015,  detailing the superconducting work he has done with other companies.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: tchernik on 05/26/2015 06:16 PM
Japan has used a Maser to beam a scale model rocket up a few feet:

Microwave powered rocket ascends without fuel

http://www.technologyreview.com/view/420700/microwave-powered-rocket-ascends-without-fuel/

That looks like a beamed energy thermal rocket.

They would most definitely work, are very scalable, but alas, not propellentless.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/26/2015 06:23 PM
Slowly making progress on this model.  This is all generated mathematically (well most of it), some is fudged a little until I have the appropriate math worked out.  This model is actually Shawyer's higher fidelity thruster with a tuning cylinder.  It also has no o-rings which I still am going back and forth on - I'm about to put them back in I think. This model does have spherical end plates.

I've just started working on the tuning mechanism. While its true that the RF can be tuned I want to do it initially by sizing the cavity and be able to see the affects of pulling the small plate in and out a small amount. 

I was going to attach the Sketchup model's file for people, but alas it's not an allowed type.

Edit: This is not Shawyer's higher fidely thruster - selected the wrong drop down from the menu - they look very similar
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/26/2015 06:36 PM
Quote from: phaseshift
I was going to attach the Sketchup model's file for people, but alas it's not an allowed type.

Make it a zip file, then attach.

Suggest you show the excitation mode (TM or TE) and m,n type as Df will change due to altering cut off wavelength.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/26/2015 06:41 PM
Quote from: phaseshift
I was going to attach the Sketchup model's file for people, but alas it's not an allowed type.

Make it a zip file, then attach.

Suggest you show the excitation mode (TM or TE) and m,n type as Df will change due to altering cut off wavelength.

Yes, that's getting adding 'shortly' - I have to labor through the math - not exactly like riding a bike, but it's slowly coming back to me :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/26/2015 06:43 PM

Make it a zip file, then attach.


Attached :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: tchernik on 05/26/2015 06:45 PM
Hello again esteemed NSF forum posters.

I have been thinking about the direction the discussion is taking, and I have to admit I am less thrilled about the theoretical explanations than about the experimental reports. Except in one point: finding potential ways to raise the thrust.

I would like to know if there is some kind of laundry list of experiments someone with an Emdrive could do to help clarify the nature of this phenomenon and validate more its existence, and eventually help others get better results. And if not, maybe add it to the Wiki.

For example, some people say the Q factor is relevant for getting more thrust, but others disagree. Maybe experiment no. 1 should be raise the Q factor somehow and see the impact on thrust at the same power input? maybe eventually do it with superconducting cavities, supposed to raise Q factor by a lot?

Some say higher power is the key. So experiment no 2 should be measuring thrust a different input power regimes?

Others say air or a dielectric inside the cavity may be relevant to having thrust or not (or much more or less). So experiment no 3. should be running it with and without a dielectric inside with a same power input, and experiment no 4. running it with and without air (e.g. with pure Nitrogen) in the cavity, maybe even with a vacuum cavity?

And so on. It seems there are many theories hinting at potential factors and explanations, and it would be great if people with so many potential explanations gave hints to the experimentalists what to do, in order to do some triage of potential causes or factors impacting thrust (and help determine if there is any anomalous thrust or not).
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/26/2015 06:50 PM
Hello again esteemed NFS forum posters.

I have been thinking about the direction the discussion is taking, and I have to admit I am less thrilled about the theoretical explanations than about the experimental reports. Except in one point: finding potential ways to raise the thrust.

I would like to know if there is some kind of laundry list of experiments someone with an Emdrive could do to help clarify the nature of this phenomenon and validate more its existence, and eventually help others get better results. And if not, maybe add it to the Wiki.

For example, some people say the Q factor is relevant for getting more thrust, but others disagree. Maybe experiment no. 1 should be raise the Q factor somehow and see the impact on thrust at the same power input? maybe eventually do it with superconducting cavities, supposed to raise Q factor by a lot?

Some say higher power is the key. So experiment no 2 should be measuring thrust a different input power regimes?

Others say air or a dielectric inside the cavity may be relevant to having thrust or not (or much more or less). So experiment no 3. should be running it with and without a dielectric inside with a same power input, and experiment no 4. running it with and without air (e.g. with pure Nitrogen) in the cavity, maybe even with a vacuum cavity?

And so on. It seems there are many theories hinting at potential factors and explanations, and it would be great if people with so many potential explanations gave hints to the experimentalists what to do, in order to do some triage of potential causes or factors impacting thrust (and help determine if there is any anomalous thrust or not).

I also think that environmental factors should be measured at the time of the experiments, temperature, humidity, barometric pressure, phase of the moon (lol), etc. would like a laundry list of those.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/26/2015 07:19 PM
Isn't there some conference set for mid-September where we might hear more one way or the other on this topic? Unfortunately for the life of me I've forgotten what it's called but, I'm sure Mr Shawyer did a presentation at it in 2013 if that helps identify it.

Shawyer did say he would be presenting a peer reviewed paper in 2015,  detailing the superconducting work he has done with other companies.

Well that's good to hear. If it's at that conference I hope there will be presentations from other interested parties.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/26/2015 07:33 PM
Based on the different theories listed in the Wiki, which one is thought to have the best predictive ability, based on the data laid out in the same Wiki?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: demofsky on 05/26/2015 07:39 PM
I really think this is a critical insight.  The microwave frequencies being used are specifically tailored to heat water (as everybody is basically using a home microwave oven emitter) - this may indeed be a water molecule amplified maser.  The humidity at time of testing in the various locations should be measured and considered as a data point in the measured thrust.

The Flight Thruster EM Drive Shawyer built for Boeing was a sealed unit and operates at 3.85GHz.
http://www.emdrive.com/flightprogramme.html

The effect we are discussing will certainly take place in a sealed unit, if the gas inside the sealed cavity has the properties required for the effect to take place.  All that is required is for the gas inside the cavity to have these properties.  As per Prof. Yang's analysis in her 2010 paper.

So how would that work? Would the gas be ionized in a preferred direction such that a gas molecule accelerated in the positive direction (to pick a coordinate direction) would be less massive (by an electron or a few electrons) than the gas returning. The ionized gas reaches the base plate and on contact is deionized by accepting electrons from the metal then the less strongly ionized (neutralized) gas is accelerated (drifts) back to the other end finding the region within the cavity where ionization occurs with electrons given up to the cavity walls or other end. The cycle repeats.

The ionized gas molecule would be slightly less massive than the neutral molecule but due to much greater charge, would move at a much higher speed, hence impart more momentum to the end plate than would the slightly more massive (heavier) but much slower neutral molecule.  The electrons added to the base plate don't actually circulate back with momentum because it is the charge that travels at near light speed, the electrons in the cavity metal oscilate with low or zero average momentum.

Paul March reported that at one time Eagleworks did use a dielectric gasket separating the big end (maybe both ends) from the frustum body but they replaced the gasket with a metal/metal contact seal. I wonder why. Perhaps without electrical continuity it didn't work.

Edit Add: I just described a recirculating ion gun didn't I? How hot is this antenna anyway?

I personally prefer to look at this as a recirculating ionic wind tunnel.    :P

Either way, zapping nice heavy ions back and forth really helps with the orders of magnitude of the effect, whatever it might be.  What might be happening is that the ions are standing in for us as nice heavy virtual protons to help out with the practical application of the various theoretical frameworks emerging here and elsewhere.  Hm. 

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/26/2015 07:52 PM
Gas model.
Pressure inside is everywhere the same. So the total force on the small end is less than that on the big end.
https://www.youtube.com/watch?v=YS9FmQPnas8

The trick is to notice what happens on the sidewalls!

So heavy ions or light atoms or light - it's all the same.
Standard physics says "no net thrust"
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/26/2015 08:15 PM
Gas model.
Pressure inside is everywhere the same. So the total force on the small end is less than that on the big end.
https://www.youtube.com/watch?v=YS9FmQPnas8

The trick is to notice what happens on the sidewalls!

So heavy ions or light atoms or light - it's all the same.
Standard physics says "no net thrust"

No no no - That's only true for static pressure case where P = Ps = constant. In the dynamic case, Pt = Ps + Pd

In the recirculating ion gun cavity model there is dynamic pressure and ram pressure to consider. The largest momentum component (and velocity) would be moving toward the small end, hence along the central axis with lesser momentum component along the frustum walls. Similar mass with some extra electrons but spread across a much larger area so lower velocity.

Look at the dynamic pressure components. Higher velocity stream along the central axis so total pressure, static plus dynamic presses the small end while the same thing happens at the large end. The difference being that dynamic pressure is 1/2 rho V2 in both cases. But much smaller velocity gives much smaller dynamic pressure

From Prof. Yang's translated paper -
Quote
regardless whether charge particles are presented within the volume, the surface electromagnetic force can change the momentum within the volume V.

As I understand it, the change in momentum results from the change in velocity of the particles (for the case with particles present) so there is more involved here than just static, dynamic or total pressure.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/26/2015 08:22 PM
I think my point is being missed for the case of a completely static gas.
I've seen people arguing for a net nonzero force even in this case.
The reason for pointing this out is to make you think.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 08:23 PM
...I have to admit I am less thrilled about the theoretical explanations than about the experimental reports...
We had discussed (towards the end of thread 2) whether to split the tread, but the overwhelming response was that "United we stand and divided we fall," that it is to the benefit of everybody to keep theoretical, experimental and strongly skeptical discussions under the same thread so that we can arrive at a common understanding of the truth behind this, which is dictated by that inflexible ruler, Mother Nature   :)


(http://www.stroudvalleyschool.co.uk/perch/resources/earth-space-space-.jpg)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: frobnicat on 05/26/2015 08:23 PM
I wonder if "sealed" and "gas tight" are truly synonymous here. After all, there is an RF connector (at least)

I'll ask Shawyer.

It wouldn't matter unless the test was done in a vacuum.  In ambient, the partial vapor pressure of the water wouldn't change (well...not much...heating MIGHT drive the moisture out somewhat).  This is a potential explanation of why there is a difference between tests at ambient pressure and those in a vacuum (if the device is NOT a pressure vessel).  Is it possible to get to White as well to ask about their test unit?

We know from at least one post of Paul March (in thread 2, but I don't have the link at hand, sorry) that the frustum at Eagleworks is not gas tight, as it was said to be venting to vacuum (when operated in vacuum). I don't recall more details about specifics, total area of gaps between inside and outside for instance. The venting seems not designed (no venting ports) but rather the consequence of no specific measure to make the frustum airtight. Also there was discussion of the gap between cone and end plates, motivated by simulations of near field with MEEP. Maybe Aero you recall the possible range for such gap ?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 08:36 PM
I think my point is being missed for the case of a completely static gas.
I've seen people arguing for a net nonzero force even in this case.
The reason for pointing this out is to make you think.
Point well taken.

It would be very useful to get strong skeptical reviews of Prof.Yang's paper ((translated) page 4 ( http://www.emdrive.com/NWPU2010translation.pdf  ) concerning her equations stating that having a gas/fluid with charged particles inside the EM Drive results in transfer of its momentum to the EM Drive metallic body. 

Just like the great job you did addressing energy conservation.

It seems to me that she also needs to take into account directional attenuation  in order to get a non-zero Poynting vector.

If you have a chance to look at her equations, I'll for one, would appreciate knowing what you think about them   :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/26/2015 08:50 PM
Quote
Maybe Aero you recall the possible range for such gap ?
Paul suggested to me that the gap could not be larger than 0.002 inches, and likely much smaller due to the frequency and tightness of the bolts holding the frustum to the end plates.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: jmossman on 05/26/2015 08:59 PM
I really think this is a critical insight.  The microwave frequencies being used are specifically tailored to heat water (as everybody is basically using a home microwave oven emitter) - this may indeed be a water molecule amplified maser.  The humidity at time of testing in the various locations should be measured and considered as a data point in the measured thrust.

The Flight Thruster EM Drive Shawyer built for Boeing was a sealed unit and operates at 3.85GHz.
http://www.emdrive.com/flightprogramme.html

The effect we are discussing will certainly take place in a sealed unit, if the gas inside the sealed cavity has the properties required for the effect to take place.  All that is required is for the gas inside the cavity to have these properties.  As per Prof. Yang's analysis in her 2010 paper.

So how would that work? Would the gas be ionized in a preferred direction such that a gas molecule accelerated in the positive direction (to pick a coordinate direction) would be less massive (by an electron or a few electrons) than the gas returning. The ionized gas reaches the base plate and on contact is deionized by accepting electrons from the metal then the less strongly ionized (neutralized) gas is accelerated (drifts) back to the other end finding the region within the cavity where ionization occurs with electrons given up to the cavity walls or other end. The cycle repeats.
(...)
Edit Add: I just described a recirculating ion gun didn't I? How hot is this antenna anyway?
(...)
Either way, zapping nice heavy ions back and forth really helps with the orders of magnitude of the effect, whatever it might be.  What might be happening is that the ions are standing in for us as nice heavy virtual protons to help out with the practical application of the various theoretical frameworks emerging here and elsewhere.  Hm.

http://forum.nasaspaceflight.com/index.php?topic=36313.msg1364682#msg1364682
Please remember that our copper frustum has a baked on silicone PCB anti-oxidation ~0.001" thick coating on its interior surfaces to keep the copper surfaces from oxidizing and thus lowering its Q-factor over time.

Wouldn't the silicone coating on the inside of EW's frustum prevent an ionization/de-ionization cycle (since neither the freed electrons and nor ions can make physical contact with the copper)?

-James
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kml on 05/26/2015 09:03 PM
Edit:  since re-reading Shawyer's paper I realized that my thrust formula is just a restatement of his but in terms of group velocity instead of guide wavelength, and with the assumption that the group velocity at the fast end = c.    And his "design factor" restated as the group velocity index n


I've been following this topic since the beginning of thread 2.   There is some great work and exchange of ideas going on here.   Everything I have read so far seems to indicate that thrust is proportional to power and Q, and inversely proportional to the group velocity at the "slow" end.

This could be explained if "slower" photons transfer a higher proportion of their energy as momentum than those in a vacuum.   I.e. If P=E/c, replace c with group velocity vg: P=E/vg.

Then, instead of the normal reflected light pressure formula (F=force, W=power):

F=2W/c

replace c with group velocity vg

F=2W/vg

Thus the net force in a resonant (Q) cavity with a slow (Fs) end and fast (Ff) end is:

F = Q(Fs - Ff)

F = Q(2W/vg - 2W/c)

Another form of this formula substituting n = c/vg = sqrt(relative permittivity * relative permeability) = index of refraction in optics:

F = Q((2Wn - 2W) / c)

may be useful for working with non-tapered dielectric-only resonators.

Working backwards with some of the published results seems to give plausible values for slow end group velocity (and therefor n):

Vg = 2W / (F/Q + 2W/C)

n = c/vg

For example one of Shawyer's experiments:
F = .016
W = 850
Q = 5900
--> n = 1.47

One of Yang's experiments (TE011 mode):
F = .214
W = 1000
Q = 32000
--> n = 2.00


Tapered waveguides, high relative permittivity, high relative permeability or any combination can reduce group velocity which explains the wide variety of geometries and configurations that have produced results.   Operating a waveguide near it's cutoff frequency presents a very steep curve of reducing group velocity and increasing transmission loss.  This explains part of the difficulty of designing and tuning the truncated cone designs.   Also, experiments done with dielectric materials so far seem to be using extremely weak dielectrics (ex: PTFE K = 2.1, n = 1.45) possibly at less than half wavelength thickness, limiting effectiveness.

Based on this it seems that maximizing group velocity differential and Q would produce the best results. I'm designing an experiment to test this theory with a simple non-tapered rectangular waveguide and various dielectrics at one end.   Sapphire (n=3 @1ghz), and Strontium Titanate (n=17 @1ghz) look like good candidates that are readily available.

Another good test of this would be a free space optical resonator with very thin dielectric attached to one mirror. 
The problem with (proposed) optical emdrive's is the limited performance of available optical dielectrics. Ultra-thin sapphire (12.5 micron, n = 1.7 @650nm) is commercially available.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Supergravity on 05/26/2015 09:10 PM
I have been thinking about the direction the discussion is taking, and I have to admit I am less thrilled about the theoretical explanations than about the experimental reports. Except in one point: finding potential ways to raise the thrust.

I wouldn't expect any coherent theoretical explanation anytime soon, or ever. This device is not based on any valid theoretical model that is consistent with mainstream science and observation. All the proposed models still allow for violations in conservation of moment or conservation of energy, or even both. Shawyer's speculation is the only slightly reasonably grounded (but still incredibly fringe) one, and the most you can get from that "model" is a drive that is about as efficient as pointing a flashlight out the back of a vehicle.

I think it speaks for itself how much attention the scientific and engineering community are paying to this work. There certainly won't be any increase thrust, as any such thrust was due to thermal or electronic noise in the first place. The experimental method is botched, and the data is incomprehensible (the error bars are far too large to make any justifiable conclusions). Also, none of it has even been peer-reviewed and the researchers don't seem to be interested in repeatability or having other researchers take a much deeper look at their work. The fact that my previous post was "widely reported" and deleted just shows how incredibly sensitive they and their supporters are to any criticism.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Davinator on 05/26/2015 09:29 PM
Your previous post was one of the worst posts on this thread, shouting "Because I don't like it you're all wrong" which is not objective, interesting or helpful to the evaluations on this thread, which has insightful posts from all sides of the argument. Because you likely felt it was a weak comment to make you ended it by attacking this site you're using to make such comments.

So you're only letting yourself down and your next post will deterime if you are welcome to continue to be part of that discussion.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: tchernik on 05/26/2015 09:31 PM
I have been thinking about the direction the discussion is taking, and I have to admit I am less thrilled about the theoretical explanations than about the experimental reports. Except in one point: finding potential ways to raise the thrust.

I wouldn't expect any coherent theoretical explanation anytime soon, or ever. This device is not based on any valid theoretical model that is consistent with mainstream science and observation. All the proposed models still allow for violations in conservation of moment or conservation of energy, or even both. Shawyer's speculation is the only slightly reasonably grounded (but still incredibly fringe) one, and the most you can get from that "model" is a drive that is about as efficient as pointing a flashlight out the back of a vehicle.

I think it speaks for themselves how much the scientific and engineering community are paying to this work. There certainly won't be any increase thrust, as any such thrust was due to thermal or electronic noise in the first place. The experimental method is botched, and the data is incomprehensible (the error bars are far too large to make any justifiable conclusions). Also, none of it has even been peer-reviewed and the researchers don't seem to be interested in repeatability or having other researchers take a much deeper look at their work. The fact that my previous post was "widely reported" and deleted just shows how incredibly sensitive they and their supporters are to any criticism.

OK. My feeling as a neophyte is that the experiments done so far do show there is some thrust and the people reporting it aren't frauds or liars, but that it isn't clear if such thrust is really an anomalous (unexplainable) one, of if it is completely mundane in its causes, like due to buoyancy or other thermal/ionic wind effects. That is, the the thrust effect is there, but the causes of it aren't clear.

Unfortunately the effect seems both small enough to be still in doubt, and large enough to be measurable. Something needs to be done to attempt to raise the effect's strength, and see if it can still occur above a threshold of reasonable doubt.

You seem to have made your mind about it, though.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Mulletron on 05/26/2015 09:33 PM


Hello i am new in this forum. Based on my own simple model(flat end plates) the frequency has to be approximately 2.52GHz.
I hope this is helpfull :)

Hi, can you share your model?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Supergravity on 05/26/2015 09:55 PM
"Because I don't like it you're all wrong" which is not objective, interesting or helpful to the evaluations on this thread, which has insightful posts from all sides of the argument.

I admit that my post was much more snarkier and offensive in hindsight, so I apologize for that. But, do you deny that the mainstream scientific and engineering community would absolutely agree and endorse the main content of my post? Would you deny that mainstream theoretical physics is largely unimpressed and even greatly annoyed by the proposed theoretical explanations for the anomalous thrust observed in these experiments?

If you see my earlier posts, you would see I've had great technical discussions with others on here about  proposed models and how it fits with current science. I would love to discuss the esoteric details of an acceptable and viable model that is put forth, but, to my knowledge, no such actual model has been proposed to date.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/26/2015 09:59 PM
I have been thinking about the direction the discussion is taking, and I have to admit I am less thrilled about the theoretical explanations than about the experimental reports. Except in one point: finding potential ways to raise the thrust.

I wouldn't expect any coherent theoretical explanation anytime soon, or ever. This device is not based on any valid theoretical model that is consistent with mainstream science and observation. All the proposed models still allow for violations in conservation of moment or conservation of energy, or even both. Shawyer's speculation is the only slightly reasonably grounded (but still incredibly fringe) one, and the most you can get from that "model" is a drive that is about as efficient as pointing a flashlight out the back of a vehicle.

I think it speaks for itself how much attention the scientific and engineering community are paying to this work. There certainly won't be any increase thrust, as any such thrust was due to thermal or electronic noise in the first place. The experimental method is botched, and the data is incomprehensible (the error bars are far too large to make any justifiable conclusions). Also, none of it has even been peer-reviewed and the researchers don't seem to be interested in repeatability or having other researchers take a much deeper look at their work. The fact that my previous post was "widely reported" and deleted just shows how incredibly sensitive they and their supporters are to any criticism.

In Shawyers Flight Thruster test the reported max thrust achieved was around 170mN.

Here and as attached.
http://emdrive.com/flightprogramme.html

That is approx 17 gf. Is a bit over the weight of 2 x US dollar coins. If I put them in your outstretched palm, could you feel the weight? Sure it is not a kg but the level is significant and not what some mosquito produces when it lands on your arm.

Comment away but maybe first do a bit of homework on the reported experimental results from Shawyer and the Chinese.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: mwvp on 05/26/2015 10:00 PM
Contemplating the least glamorous hypothesis for the, as yet sparsely confirmed effect, I considered asymmetric thermal dissipation of forward/backward (or thrust/reaction) momentum, as sorted by frequency components by the frustrum.

Then, in a flash of insight, I though of the Peltier cooler I saw at my favorite shop, the Goodwill Store. Only $8. Alas, why didn't I buy it yesterday?

And I remembered, years long past on a blog far, far away, a very similar campaign raged over thrust from a Peltier device, valid thrust measurement, thermal effects, et.

But I digress. My notion de jour:

Shawyer began his recently posted youtube interview by stating, as I recall, of his career in missile guidance in the 70's. Thoughts of fiber-optic gyros, Sagnac effect, et. come to mind.

Consider such a ring gyro with counter-propagating beams smushed from a circle into a linear waveguide, forward and reverse waves creating a single standing wave. Would not such a system, on long-axis (Z) acceleration, have forward and reverse components split into sum and difference frequencies?

A frustrum waveguide is electrically long at one end, short on the other, capacitive and inductive respectively. Or one might well think of using two, or more, coupled cavities, leading end tuned to a higher frequency than the trailing. And now, consider the low-frequency cavity as more lossy or dissipative than the high.

Asymmetrical frequency attenuation results in the dispersive line. The large end of the frustrum is more inductive and has higher I^2*L losses than the pointy-end capacitive loss. The momentum is radiated away as heat. See the Eagleworks TM212 frustrum tail glow?

It is not a closed system violating CoM, it is an open-system, separating forward and reverse propagating electromagnetic momentum by frequency, with the dispersive cavity then selectively dissipating and radiating the sorted momentum as heat.

As, I know, this has been espoused by some here prior. I'm just kind of slow on the uptake.

So why would a Peltier cooler generate thrust? An electric current drags high-frequency (hot) phonons from one end and leaving low-frequency (cold) phonons on the other. Kind of the same thing, in another media and operating regime. Or something like that.

I googled "Peltier Thrust" and found this:
http://www.theavalonfoundation.org/docs/peltier.html

Hal Puthoff mentioned. Usual suspect?

So, pending more evidence, at this time I'm persuaded this is a thermodynamic rather than a qv warping/compressing phenomena. I change my mind often about this stuff over the last couple weeks. If true, it precludes some exciting and energetic plasma applications.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/26/2015 10:02 PM
A physicist pal has asked me a question I cannot answer about this stuff and so I will repeat it here:
"I want to know how they actually determine what the Q actually IS for the resonant mode of the particular cavity they are actually using. "
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Davinator on 05/26/2015 10:05 PM
"Because I don't like it you're all wrong" which is not objective, interesting or helpful to the evaluations on this thread, which has insightful posts from all sides of the argument.

I admit that my post was much more snarkier and offensive in hindsight, so I apologize for that. But, do you deny that the mainstream scientific and engineering community would absolutely agree and endorse the main content of my post? Would you deny that mainstream theoretical physics is largely unimpressed and even greatly annoyed by the proposed theoretical explanations for the anomalous thrust observed in these experiments?

If you see my earlier posts, you would see I've had great technical discussions with others on here about  proposed models and how it fits with current science. I would love to discuss the esoteric details of an acceptable and viable model that is put forth, but, to my knowledge, no such actual model has been proposed to date.

My answer is I don't know. Like most people here, we mainly discuss things from Shuttle to SLS. These advanced topic threads are very specailist and I have no dog in this race.

All I'm saying, per my post, is these threads still fall under the same moderation where you can have any opinion, but you have to present it within site rules. That other post had some unacceptable comments in it and that results in a deleted post.  I'm a moderator so I had to post.

And to show it's nothing to do with whatever opinion people have, the above post is completely fine!
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/26/2015 10:15 PM
"Because I don't like it you're all wrong" which is not objective, interesting or helpful to the evaluations on this thread, which has insightful posts from all sides of the argument.

I admit that my post was much more snarkier and offensive in hindsight, so I apologize for that. But, do you deny that the mainstream scientific and engineering community would absolutely agree and endorse the main content of my post? Would you deny that mainstream theoretical physics is largely unimpressed and even greatly annoyed by the proposed theoretical explanations for the anomalous thrust observed in these experiments?

If you see my earlier posts, you would see I've had great technical discussions with others on here about  proposed models and how it fits with current science. I would love to discuss the esoteric details of an acceptable and viable model that is put forth, but, to my knowledge, no such actual model has been proposed to date.

My answer is I don't know. Like most people here, we mainly discuss things from Shuttle to SLS. These advanced topic threads are very specailist and I have no dog in this race.

All I'm saying, per my post, is these threads still fall under the same moderation where you can have any opinion, but you have to present it within site rules. That other post had some unacceptable comments in it and that results in a deleted post.  I'm a moderator so I had to post.

And to show it's nothing to do with whatever opinion people have, the above post is completely fine!

The OP is also overlooking the fact that if there was anything in this that it would be so revolutionary that much of the testing would be done probably behind a cloud due to commercial considerations. For example Boeing might be doing nothing or everything with that drive they have.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 10:23 PM
A physicist pal has asked me a question I cannot answer about this stuff and so I will repeat it here:
"I want to know how they actually determine what the Q actually IS for the resonant mode of the particular cavity they are actually using. "
This is a very important question, that I raised before concerning the non-orthodox way that Yang et.al. report her Q's which is very different from what is done in the West.

As to how NASA Brady et.al report their Q's my understanding is that it is entirely based on S11 and S21 as for example detailed in the following reference:

A. Podcameni, L. F. M. Conrado, and M. M. Russo, “Unloaded quality factor measurement for MIC dielectric resonator application,” Electronics Letters, vol. 17, pp. 656-658, 1981.
DOI:  10.1049/el:19810459 , Print ISSN 0013-5194, Online ISSN 1350-911X
http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4245936&filter%3DAND%28p_IS_Number%3A4245914%29

which reports a procedure for scalar reaction-type measurements, using only the amplitudes of S11 and S21 for determining the loaded and unloaded Q.

Caveats:  I don't recall people bringing up this reference in these threads in the past.  This is my own understanding. Everybody is urged to comment so that we can assess how did Shawyer, Brady et.al, Fetta and Yang et.al. report their Q's.  Otherwise discussion of Q resonance is like the tower of Babel.



Alternatively, I have seen discussion in this thread of calculating the loaded Q of the system as inversely
proportional to the difference between the 3-dB frequencies f1 and f2 around fo

loadedQ=fo /(f2-f1). 

Then the unloaded Q can be calculated as the loaded Q divided by (1-S21(fo))

unloadedQ =  loadedQ / (1-S21(fo))
                = fo /((f2-f1) *(1-S21(fo)) )

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: ragingrei on 05/26/2015 10:31 PM
But, do you deny that the mainstream scientific and engineering community would absolutely agree and endorse the main content of my post? Would you deny that mainstream theoretical physics is largely unimpressed and even greatly annoyed by the proposed theoretical explanations for the anomalous thrust observed in these experiments?

I liken the situation to the Mpemba effect (https://en.wikipedia.org/wiki/Mpemba_effect), where hot water sometimes freezes faster than cold water. Very few scientists are going to pursue it even though the experiment is easily replicable and relatively inexpensive, because it seems completely absurd. Yet, whether or not there's a radical explanation or a very mundane one, there are people interested in refining their experiments and attempting to explain it.

The difference between that and the EM Drive is that, as far as I know, those who choose not to pursue the Mpemba effect don't become furious at those who do.

There should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: wallofwolfstreet on 05/26/2015 10:37 PM
I have seen a few posts recently speculating about whether or not Boeing is developing this technology secretly to preserve commercial interests/IP.  While I am unable to say for certain either way, the follow link contains quotes given by Shawyer that lead me to believe they are not:

http://www.ibtimes.co.uk/nasa-validates-emdrive-roger-shawyer-says-aerospace-industry-needs-watch-out-1499141

Quote:
"When pressed about who Shawyer might be working with on EmDrive technology, he said cryptically: "You need to think about which countries who don't have a vested interest in the aerospace long-haul aircraft industries – they will not be the Boeings and the Airbuses, but some of the developing nations.""


Note that this interview was given after the Boeing technology transfer deal.  Since he specifically mentioned Boeing by name as a company he is NOT working with, I think we may have to conclude that the Boeing technology transfer deal must not have led to any developments.

(We could guess that Boeing is developing the technology under such close secrecy that SHawyer himself doesn't know about it, or that Shawyer is trying to throw off the trail, but that is getting a bit conspiratorial.)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kdhilliard on 05/26/2015 10:55 PM
In Shawyers Flight Thruster test the reported max thrust achieved was around 170mN.
...
That is approx 17 gf. Is a bit over the weight of 2 x US dollar coins. If I put them in your outstretched palm, could you feel the weight? Sure it is not a kg but the level is significant and not what some mosquito produces when it lands on your arm.

Traveller, do you know how Shawyer actually measured thrust, because according to his EmDriveForceMeasurement.pdf (http://www.emdrive.com/EmDriveForceMeasurement.pdf) and due to his strange interpretation of action and reaction, he believes that direct measurement of the thrust from a non-accelerating EmDrive is impossible, and the test rigs discussed here, including Iulian's balance, should not measure any thrust at all.
Quote from: Pg. 2
The most important point to be made, is that to measure force, the cavity must experience acceleration. In a fully restrained cavity, thrust and reaction force cancel out. ...

Clearly, in a static situation, where T and R both exist as forces, they will cancel out. Thus any attempt to measure them by simply placing the thruster vertically on a set of scales will fail. If however the thrust is sufficient such that a = -g, then the thruster could be made to hover above the scales. ...

In free space, the thruster will simply accelerate at a m/s/s, and R will not be measurable. To measure R it is necessary to restrain the thruster against a fixed reference point.

However at rest, no force can be measured as R will cancel out T as in Fig 1. ...
and most importantly
Quote from: Pg. 3
A number of methods have been used in the UK, the US and China to measure the forces produced by an EmDrive thruster. In each successful case, the EmDrive force data has been superimposed on an increasing or decreasing background force, generated by the test equipment itself.

Indeed, in the UK when the background force changes were eliminated, in an effort to improve force measurement resolution, no EmDrive force was measured. This was clearly a result of attempting to measure the forces on a fully static thruster, where T and R cancel each other.

Does that mean that Shaywer's device includes actuators which accelerate the drive, and the measured thrust is extracted from the signal by subtracting the expected contribution of those actuators?

~Kirk
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/26/2015 10:59 PM
I have seen a few posts recently speculating about whether or not Boeing is developing this technology secretly to preserve commercial interests/IP.  While I am unable to say for certain either way, the follow link contains quotes given by Shawyer that lead me to believe they are not:

http://www.ibtimes.co.uk/nasa-validates-emdrive-roger-shawyer-says-aerospace-industry-needs-watch-out-1499141

Quote:
"When pressed about who Shawyer might be working with on EmDrive technology, he said cryptically: "You need to think about which countries who don't have a vested interest in the aerospace long-haul aircraft industries – they will not be the Boeings and the Airbuses, but some of the developing nations.""


Note that this interview was given after the Boeing technology transfer deal.  Since he specifically mentioned Boeing by name as a company he is NOT working with, I think we may have to conclude that the Boeing technology transfer deal must not have led to any developments.

(We could guess that Boeing is developing the technology under such close secrecy that SHawyer himself doesn't know about it, or that Shawyer is trying to throw off the trail, but that is getting a bit conspiratorial.)

Any kind of technology whatever it was that was being actively developed in the black world would at no time be confirmed by even its inventor as they would be subject to strict NDAs. So we can take nothing from that article. I'm not saying it is in this case merely that if it was that would be the kind of answer you might well get.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/26/2015 11:09 PM
I have seen a few posts recently speculating about whether or not Boeing is developing this technology secretly to preserve commercial interests/IP.  While I am unable to say for certain either way, the follow link contains quotes given by Shawyer that lead me to believe they are not:

http://www.ibtimes.co.uk/nasa-validates-emdrive-roger-shawyer-says-aerospace-industry-needs-watch-out-1499141

Quote:
"When pressed about who Shawyer might be working with on EmDrive technology, he said cryptically: "You need to think about which countries who don't have a vested interest in the aerospace long-haul aircraft industries – they will not be the Boeings and the Airbuses, but some of the developing nations.""


This says what Shawyer said in the first of the interview videos posted a few days ago - companies like Boeing and Airbus have a vested interest in aerospace and this would be highly highly disruptive. It could easily topple the companies if it bore fruit. If anything, you would expect companies like these to do what they can, if they feel it necessary, to be disruptive of the technology themselves.

On the other hand, with the money of the U.S. Military behind it, these companies would probably be able to weather such a disruptive technology.  Given that there would be military applications, and that Boeing appears to not be pursuing it (though they are a defense contractor), the conclusion is that they feel nothing is there.

So the question is, "Why hasn't Boeing simply stated that it doesn't work?" - seems simple enough, what's the downside of such a statement?

Has anyone looked through DARPA RFPs for anything related to EMdrives?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Mulletron on 05/26/2015 11:18 PM
Interesting result. Still searching for symmetry violations.

Observation of a Chiral State in a Microwave Cavity
C. Dembowski, B. Dietz, H.-D. Gräf, H. L. Harney, A. Heine, W. D. Heiss, and A. Richter
Phys. Rev. Lett. 90, 034101 – Published 23 January 2003

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.90.034101
http://arxiv.org/pdf/nlin/0212023v2.pdf

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: wallofwolfstreet on 05/26/2015 11:30 PM
I have seen a few posts recently speculating about whether or not Boeing is developing this technology secretly to preserve commercial interests/IP.  While I am unable to say for certain either way, the follow link contains quotes given by Shawyer that lead me to believe they are not:

http://www.ibtimes.co.uk/nasa-validates-emdrive-roger-shawyer-says-aerospace-industry-needs-watch-out-1499141

Quote:
"When pressed about who Shawyer might be working with on EmDrive technology, he said cryptically: "You need to think about which countries who don't have a vested interest in the aerospace long-haul aircraft industries – they will not be the Boeings and the Airbuses, but some of the developing nations.""


Note that this interview was given after the Boeing technology transfer deal.  Since he specifically mentioned Boeing by name as a company he is NOT working with, I think we may have to conclude that the Boeing technology transfer deal must not have led to any developments.

(We could guess that Boeing is developing the technology under such close secrecy that SHawyer himself doesn't know about it, or that Shawyer is trying to throw off the trail, but that is getting a bit conspiratorial.)

Any kind of technology whatever it was that was being actively developed in the black world would at no time be confirmed by even its inventor as they would be subject to strict NDAs. So we can take nothing from that article. I'm not saying it is in this case merely that if it was that would be the kind of answer you might well get.

While you are right of course about the NDA, that really doesn't apply in this case I feel.  The interviewer didn't ask him "Is Boeing developing the technology?"; he was the one who brought up Boeing, not her (as far as I can tell).  If this was an NDA issue, there would be absolutely no reason to bring them up unless explicitly asked about them. 

Also, an NDA merely states that you can't confirm one way or another (ie. he should have said "no comment").  As far as I know, there is no such thing as an agreement that requires you to actively deny/be misleading about something.  Would such an agreement even be legal?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: nilabrk on 05/26/2015 11:37 PM
BTW The entire bread crumb thing makes me cringe.

So many times I've seen the case of a deluded researcher giving hints that, in retrospect, say: 'I don't know the answer, but I'm going to drop my hunches as if I know, and then take the credit when you find something interesting.' That's really been the trend in any kind of bogus technology guru situation. 

No offense to The Traveler -- just a heads up that the breadcrumb thing is a trope of rag-trade paperbacks and soap operas to get you to stick around after the ad-break/chapter. But good luck if you are able to get a head start before his peer reviewed paper comes out (that's a thing right? Aside from EW's forthcoming publication?). I think, with Shawyer at least, a good dollop of blind faith is required to remain satisfied.  :-\
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/26/2015 11:39 PM
In Shawyers Flight Thruster test the reported max thrust achieved was around 170mN.
...
That is approx 17 gf. Is a bit over the weight of 2 x US dollar coins. If I put them in your outstretched palm, could you feel the weight? Sure it is not a kg but the level is significant and not what some mosquito produces when it lands on your arm.

Traveller, do you know how Shawyer actually measured thrust, because according to his EmDriveForceMeasurement.pdf (http://www.emdrive.com/EmDriveForceMeasurement.pdf) and due to his strange interpretation of action and reaction, he believes that direct measurement of the thrust from a non-accelerating EmDrive is impossible, and the test rigs discussed here, including Iulian's balance, should not measure any thrust at all.
Quote from: Pg. 2
The most important point to be made, is that to measure force, the cavity must experience acceleration. In a fully restrained cavity, thrust and reaction force cancel out. ...

Clearly, in a static situation, where T and R both exist as forces, they will cancel out. Thus any attempt to measure them by simply placing the thruster vertically on a set of scales will fail. If however the thrust is sufficient such that a = -g, then the thruster could be made to hover above the scales. ...

In free space, the thruster will simply accelerate at a m/s/s, and R will not be measurable. To measure R it is necessary to restrain the thruster against a fixed reference point.

However at rest, no force can be measured as R will cancel out T as in Fig 1. ...
and most importantly
Quote from: Pg. 3
A number of methods have been used in the UK, the US and China to measure the forces produced by an EmDrive thruster. In each successful case, the EmDrive force data has been superimposed on an increasing or decreasing background force, generated by the test equipment itself.

Indeed, in the UK when the background force changes were eliminated, in an effort to improve force measurement resolution, no EmDrive force was measured. This was clearly a result of attempting to measure the forces on a fully static thruster, where T and R cancel each other.

Does that mean that Shaywer's device includes actuators which accelerate the drive, and the measured thrust is extracted from the signal by subtracting the expected contribution of those actuators?

~Kirk

Not at my laptop. I have images of each case below.

He has placed them directly on scales, hung them from springs above scales, used balance beams with scales, plus he used a rotary air bearing system to show true acceleration.

Seems his preferred method is to work either against gravity (small end pushing up) or with gravity (small end pushing down).
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kdhilliard on 05/26/2015 11:54 PM
In Shawyers Flight Thruster test the reported max thrust achieved was around 170mN.
...
That is approx 17 gf. Is a bit over the weight of 2 x US dollar coins. If I put them in your outstretched palm, could you feel the weight? Sure it is not a kg but the level is significant and not what some mosquito produces when it lands on your arm.

Traveller, do you know how Shawyer actually measured thrust, because according to his EmDriveForceMeasurement.pdf (http://www.emdrive.com/EmDriveForceMeasurement.pdf) and due to his strange interpretation of action and reaction, he believes that direct measurement of the thrust from a non-accelerating EmDrive is impossible, and the test rigs discussed here, including Iulian's balance, should not measure any thrust at all.
Quote from: Pg. 2
The most important point to be made, is that to measure force, the cavity must experience acceleration. In a fully restrained cavity, thrust and reaction force cancel out. ...

Clearly, in a static situation, where T and R both exist as forces, they will cancel out. Thus any attempt to measure them by simply placing the thruster vertically on a set of scales will fail. If however the thrust is sufficient such that a = -g, then the thruster could be made to hover above the scales. ...

In free space, the thruster will simply accelerate at a m/s/s, and R will not be measurable. To measure R it is necessary to restrain the thruster against a fixed reference point.

However at rest, no force can be measured as R will cancel out T as in Fig 1. ...
and most importantly
Quote from: Pg. 3
A number of methods have been used in the UK, the US and China to measure the forces produced by an EmDrive thruster. In each successful case, the EmDrive force data has been superimposed on an increasing or decreasing background force, generated by the test equipment itself.

Indeed, in the UK when the background force changes were eliminated, in an effort to improve force measurement resolution, no EmDrive force was measured. This was clearly a result of attempting to measure the forces on a fully static thruster, where T and R cancel each other.

Does that mean that Shaywer's device includes actuators which accelerate the drive, and the measured thrust is extracted from the signal by subtracting the expected contribution of those actuators?

Not at my laptop. I have images of each case below.

He has placed them directly on scales, hung them from springs above scales, used balance beams with scales, plus he used a rotary air bearing system to show true acceleration.

Seems his preferred method is to work either against gravity (small end pushing up) or with gravity (small end pushing down).

Interesting.  Do you then agree that his EmDriveForceMeasurement.pdf suggests that with such methods no EmDrive force would be measured?

~Kirk

P.S. On a personal note, I hope you know that no one here is calling on you to defend Shawyer's position.  You just seem to be the one most familiar with his work.  I find his treatment of action-reaction to be very confusing, and I'd appreciate any breadcrumbs I get from you which would help explain just what he is thinking.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/26/2015 11:58 PM
...

I think it speaks for itself how much attention the scientific and engineering community are paying to this work. There certainly won't be any increase thrust, as any such thrust was due to thermal or electronic noise in the first place. The experimental method is botched, and the data is incomprehensible (the error bars are far too large to make any justifiable conclusions). Also, none of it has even been peer-reviewed and the researchers don't seem to be interested in repeatability or having other researchers take a much deeper look at their work. The fact that my previous post was "widely reported" and deleted just shows how incredibly sensitive they and their supporters are to any criticism.
Factual correction:  Prof. Yang's papers (on her theoretical analysis and experimental measurements of the EM Drive) have been published in the peer-reviewed journal Acta Physica Sinica -Chinese Edition- (ACTA PHYS SIN-CH ED)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 12:04 AM
BTW The entire bread crumb thing makes me cringe.

So many times I've seen the case of a deluded researcher giving hints that, in retrospect, say: 'I don't know the answer, but I'm going to drop my hunches as if I know, and then take the credit when you find something interesting.' That's really been the trend in any kind of bogus technology guru situation. 

No offense to The Traveler -- just a heads up that the breadcrumb thing is a trope of rag-trade paperbacks and soap operas to get you to stick around after the ad-break/chapter. But good luck if you are able to get a head start before his peer reviewed paper comes out (that's a thing right? Aside from EW's forthcoming publication?). I think, with Shawyer at least, a good dollop of blind faith is required to remain satisfied.  :-\

With respect. Your opinion. Not mine.

Shawyer is under no obligation to help replication like me. He has clients that have entered into commercial arrangements with SPR & he needs to respect those contracts and the licensed IP.

I have information I can't disclose, yet, and not from Shawyer directly, that has removed any last little bit of doubt I had the thrust is very real. However like any new tech, still in development, there are issues that can cloud performance. As I was told my one replication, keeping a high Q frustum working at optimal Rf frequency is NOT easy. Smallest drift off and thrust stops. Constantly changing temp of various frustum areas also changes cavity frequency enough to detune. Cavity Q of 50,000 to 60,000 sounds great to get good thrust but it turns into a monster intent on NOT producing thrust.

Based on what I have learned, blasting away with a wide band magnetron into a low Q cavity may be a good option as it really reduces lost/NO thrust from being constantly off resonance with a high Q cavity.

I'm told the peer reviewed paper Shawyer will present in 2015,  with his commercial partners, will be an eye opened. No more doubts. All over. Time to start building or buying as the case may be EM Drives.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/27/2015 12:09 AM

...

Therefore, any propellant-less propulsion device, must have some means of becoming depolarized. In the case of the frustum, stored energy is lost to heat as well as thrust, and this eventually depolarizes it so it can be re-charged and thrust again. Once again, it can only work in a pulsed mode, when power is ramping up and down quickly.

Todd
What do people think of the idea of driving the EM Drive with a TEmnp mode (transverse electric mode) such that the axial field is magnetic along the longitudinal direction.

This would be a solenoid, aka transformer primary or coupled inductor oriented axially with the frustum. It is a straightforward design I have been considering...

Quote
Then the idea would be to make the EM Drive more of a "one-way" street (1-way directional waves rather than a 2-way street with standing waves) by placing tiny ferrite beads (magnets) along so as to minimize reflections (as done in the solid state ruby maser).

The number and size of the ferrite beads would control the fine tradeoff between Q resonance (needed for reverberation) and directionality (needed for thrust).

How? Any magnetic material along the axis will transfer momentum forward to the frustum, but only at the expense of recoiling momentum toward the rear. If they are physical attached to one another, the result should be nil.

Quote

Perhaps this would allow the use of a cylindrical waveguide (instead of a truncated cone), one could control the amount of reflections by the size and number of ferrite beads along the axis.  (The size of the ferrite bead could be functionally graded such that the size of ferrite would monotonically increase in one direction, for example).

Also the use of a solid state material (such as the ruby used in the ruby maser) that can emit in a very wide range of microwave frequencies may allow much higher power to thrust force conversion.

Please notice as per the history of the Ruby Maser chart, that many Ruby Masers operated at similar microwave frequencies (2.4 GHz) as used for magnetrons for home cooking microwave ovens:

It's still beyond my comprehension at the moment. I'll give it some thought and do some research.

Todd
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 12:18 AM

...

Therefore, any propellant-less propulsion device, must have some means of becoming depolarized. In the case of the frustum, stored energy is lost to heat as well as thrust, and this eventually depolarizes it so it can be re-charged and thrust again. Once again, it can only work in a pulsed mode, when power is ramping up and down quickly.

Todd
What do people think of the idea of driving the EM Drive with a TEmnp mode (transverse electric mode) such that the axial field is magnetic along the longitudinal direction.

This would be a solenoid, aka transformer primary or coupled inductor oriented axially with the frustum. It is a straightforward design I have been considering...

Quote
Then the idea would be to make the EM Drive more of a "one-way" street (1-way directional waves rather than a 2-way street with standing waves) by placing tiny ferrite beads (magnets) along so as to minimize reflections (as done in the solid state ruby maser).

The number and size of the ferrite beads would control the fine tradeoff between Q resonance (needed for reverberation) and directionality (needed for thrust).

How? Any magnetic material along the axis will transfer momentum forward to the frustum, but only at the expense of recoiling momentum toward the rear. If they are physical attached to one another, the result should be nil.

Quote

Perhaps this would allow the use of a cylindrical waveguide (instead of a truncated cone), one could control the amount of reflections by the size and number of ferrite beads along the axis.  (The size of the ferrite bead could be functionally graded such that the size of ferrite would monotonically increase in one direction, for example).

Also the use of a solid state material (such as the ruby used in the ruby maser) that can emit in a very wide range of microwave frequencies may allow much higher power to thrust force conversion.

Please notice as per the history of the Ruby Maser chart, that many Ruby Masers operated at similar microwave frequencies (2.4 GHz) as used for magnetrons for home cooking microwave ovens:

It's still beyond my comprehension at the moment. I'll give it some thought and do some research.

Todd

Dissipation in masers is produced by

1) the resistance of the copper structure,  (all EM Drives use this)
2) dielectric material loss  (NASA uses this)
3) ferrite magnetic permeability(apparently nobody has tried this, although Aquino suggested it)

You agree that attenuation (hence dissipation) gradient is responsible for the thrust in an EM Drive.

The EM Drive at NASA uses dielectric inserts (HDPE) which are most effective in TM transverse magnetic modes because they have an electric field in the axial direction (NASA is using mode TM212)

If you look at the numerical value of the relative magnetic permeability of ferrites you will see that probably we can accomplish much more by using ferrite inserts in TE modes (that have an axial magnetic field) than what we can accomplish with dielectric inserts in TM modes (that have an electric field in the axial direction) using their relative electric permittivity (look at their numerical value ~2).

We discussed much earlier in the thread having a single ferrite at one end (one of the end plates) in TE modes, just like NASA uses a single dielectric HDPE polymer insert in mode TM modes.  (See the paper by Aquino "How the Thrust of Shawyer’s Thruster can be Strongly Increased" ( https://hal.archives-ouvertes.fr/hal-01074608/document) and my comment here: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1328595#msg1328595 )

We could have a functionally graded distribution of small dielectric inserts or small  ferrite inserts with ruby in between them, as in a maser.  The inserts should not occupy the whole cross section but just a small portion of it (in masers the ferrite beads are very small, placed at the combs).

The size of the dielectric (for TM modes) or the ferrite (TE modes) would monotonically increase from one end to the other (when using several inserts).

But, if you cannot meet me (perhaps yet) at the concept of a gradient of small ferrites distributed in the axial direction, can you please consider at least one ferrite insert at one end (as proposed by Aquino) ?

How about one ruby ?

http://deepblue.lib.umich.edu/bitstream/handle/2027.42/70658/JAPIAU-30-7-1061-1.pdf?sequence=2
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 12:22 AM
Quote from: kdhilliard

Interesting.  Do you then agree that his EmDriveForceMeasurement.pdf suggests that with such methods no EmDrive force would be measured?

~Kirk

P.S. On a personal note, I hope you know that no one here is calling on you to defend Shawyer's position.  You just seem to be the one most familiar with his work.  I find his treatment of action-reaction to be very confusing, and I'd appreciate any breadcrumbs I get from you which would help explain just what he is thinking.

To be free to move or not is a relative term. How much movement is free to move? Bolt it to a satellite and it will not move relative to the satellite. Sit it on a scale and it can press down, move a micron and generate a force.

Sometime Roger Shawyer is not the best of technical writers and you need to do a bit of head scratching to understand his point of view.

I have no issues with the measurement paper and using scales to measure the force as the EM Drive does move on a scale, even if you can't see it.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/27/2015 12:38 AM
(...)
It is not a closed system violating CoM, it is an open-system, separating forward and reverse propagating electromagnetic momentum by frequency, with the dispersive cavity then selectively dissipating and radiating the sorted momentum as heat.

As, I know, this has been espoused by some here prior. I'm just kind of slow on the uptake.

So why would a Peltier cooler generate thrust? An electric current drags high-frequency (hot) phonons from one end and leaving low-frequency (cold) phonons on the other. Kind of the same thing, in another media and operating regime. Or something like that.

I googled "Peltier Thrust" and found this:
http://www.theavalonfoundation.org/docs/peltier.html

Hal Puthoff mentioned. Usual suspect?

So, pending more evidence, at this time I'm persuaded this is a thermodynamic rather than a qv warping/compressing phenomena. I change my mind often about this stuff over the last couple weeks. If true, it precludes some exciting and energetic plasma applications.

Well put! The Peltier Thruster (PT) is a prime example of what I was talking about in another post. That any power to acceleration transducer can also be used to the opposite effect, but once it becomes polarized it's useless. In the case of the PT, once it reaches its ultimate thermal differential, there is no more thrust.

I was thinking along the same lines actually. Maxwell's demon, putting more energetic particles forward and slower ones backwards. That's what the Peltier effect does, but you must input power to do it. Thrust exponentially decays as temperature difference stabilizes. It makes sense to me anyway.

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/27/2015 12:51 AM
Just an FYI putting the power gain stage into the cavity itself as an oscillator..  Greatly simplifies the circuitry and operation.  Been there, successfully done that.  But, it's not the best method if you are trying to take precision measurements against a external frequency standard.  (found that out right away)

This is all I can find that is similar to what we would make as kids  (my uncle had a lathe in his basement)

http://www.google.st/patents/US2797324

I would hope for something solid state w/ more power than a diode to be available by now.

OK, done w/ the rant...
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 01:21 AM
Quote from: kdhilliard

Interesting.  Do you then agree that his EmDriveForceMeasurement.pdf suggests that with such methods no EmDrive force would be measured?

~Kirk

P.S. On a personal note, I hope you know that no one here is calling on you to defend Shawyer's position.  You just seem to be the one most familiar with his work.  I find his treatment of action-reaction to be very confusing, and I'd appreciate any breadcrumbs I get from you which would help explain just what he is thinking.

To be free to move or not is a relative term. How much movement is free to move? Bolt it to a satellite and it will not move relative to the satellite. Sit it on a scale and it can press down, move a micron and generate a force.

Sometime Roger Shawyer is not the best of technical writers and you need to do a bit of head scratching to understand his point of view.

I have no issues with the measurement paper and using scales to measure the force as the EM Drive does move on a scale, even if you can't see it.

<<To be free to move or not is a relative term. How much movement is free to move? >>

Fortunately we have the field of Mechanics that has answered this question.

displacement = (Force/ModulusOfElasticity)*( Length/CrossSectionalArea)

so, given an arbitrary Force, and any arbitrary geometrical dimensions, in order to have zero displacement you need to have a material with Infinite modulus of elasticity.

The answer is that there is no such Infinitely stiff material in our Universe.   ;)

So whoever asks for zero deformation, has to more rigorously define precisely what they mean by that.

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/27/2015 01:24 AM
That's why we always used a calibrated feedback force.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kdhilliard on 05/27/2015 01:34 AM
Quote from: kdhilliard

Do you then agree that his EmDriveForceMeasurement.pdf suggests that with such methods no EmDrive force would be measured?
To be free to move or not is a relative term. How much movement is free to move? Bolt it to a satellite and it will not move relative to the satellite. Sit it on a scale and it can press down, move a micron and generate a force.

Sometime Roger Shawyer is not the best of technical writers and you need to do a bit of head scratching to understand his point of view.

I have no issues with the measurement paper and using scales to measure the force as the EM Drive does move on a scale, even if you can't see it.
Fortunately we have the field of Mechanics that has answered this question.  ...

I absolutely agree that there cannot be any force measurement without some displacement, however small that displacement might be given the sensitivity of modern load cells, and I tried to interpret Shawyer's measurement paper that way, but his
Quote from: Pg. 3
A number of methods have been used in the UK, the US and China to measure the forces produced by an EmDrive thruster. In each successful case, the EmDrive force data has been superimposed on an increasing or decreasing background force, generated by the test equipment itself.

Indeed, in the UK when the background force changes were eliminated, in an effort to improve force measurement resolution, no EmDrive force was measured. This was clearly a result of attempting to measure the forces on a fully static thruster, where T and R cancel each other.
sure sounds like there must be more to his test rigs than meets the eye.

~Kirk
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: ThinkerX on 05/27/2015 01:58 AM
Ok...the more pictures I see of Shawyer's 'Flight Thruster' the more it seems to me this is something he adapted, rather than built, at least for the shell.  To me, it looks like a reducer coupling, of the sort used to connect different diameters of pipe.  If memory serves, those are usually forged all in one piece.

So, for the DIY types, maybe check out the selection at a really big plumbing supply outfit?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 02:05 AM
(http://imgp0.en.makepolo.net/m/485/276/aca81ff1cf98f1189f0e52179407dfd4.jpg)

(http://3.imimg.com/data3/RB/KE/MY-2552216/concentric-reducer-500x500.jpg)

http://www.pipetubeflanges.com/fittings.html
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/27/2015 02:12 AM
(http://imgp0.en.makepolo.net/m/485/276/aca81ff1cf98f1189f0e52179407dfd4.jpg)
String them together in your idea and add a ferrite bead. Looks good Dr. Rodal.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/27/2015 02:16 AM

The answer is that there is no such Infinitely stiff material in our Universe.   ;)


True! But space-time (vacuum) comes close!  ;D
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: ThinkerX on 05/27/2015 02:34 AM
Doctor Rodal -  Those seem promising: polished interior, no seams, and designed to withstand a lot of pressure without deforming, hence less hassle from thermal issues.  A couple of those, just eyeballing it, look close to the angles most frequently brought up here. 

Been ages since I worked with these things, but I'm almost willing to bet those same shops would have something that could be finagled into the end plates as well. 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/27/2015 03:29 AM
I have an interesting question / thought experiment in need of some input.

Suppose we have a perfectly conducting cylinder and we inject microwaves into the side, at the center of the cylinder. Their momentum propagates equally in both directions and the reflections result in standing waves. At one end of the cylinder, there is a thin layer of water sealed behind glass which is transparent to microwaves. At the other end, there is a perfect reflector. Should there be NET thrust now? Energy is being used to heat the water on one side, while the other side is receiving all of the momentum that is reflected from it.

The answer is, momentum is NOT conserved in dissipative systems. There should be thrust in proportion to the amount of heat that can be absorbed by the water. It's heat capacity is not infinite so eventually the system becomes polarized, until the water is allowed to cool.

@Rodal mentioned making the cavity a one-way street. Another idea would be to make the frustum out of different metals. Having zinc at one end and copper at the other end will form a galvanic cell, but it also forms a crude diode! This makes it more difficult for current to flow in one direction vs the other direction in the frustum, accomplishing that goal. Different metals can also make it more or less dissipative at each end.

Todd
 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zen-in on 05/27/2015 03:45 AM
A recent NASA solicitation titled "Utilizing Public - Private partnerships to Advance Tipping Point Technologies"  has a section that request proposals for Small satellite propulsion systems, with funding of up to $2M. 
"Relatively mature or especially novel technology"
 
"NASA is seeking propulsion systems that are ready or nearly ready for demonstration in space, meaning that the offeror could deliver flightready hardware within 6 to 18 months of award. NASA intends to then integrate those systems into CubeSat-scale satellites."

http://nspires.nasaprs.com/external/solicitations/summary.do?method=init&solId={ED1BDB01-28C8-6859-E277-ED206F8B6D68}&path=open
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/27/2015 03:53 AM
Does anyone have a copy?

High Q Resonant Cavities for Microwave Testing (pages 408–434)
I. G. Wilson, C. W. Schramm and J. P. Kinzer
Article first published online: 29 JUL 2013 | DOI: 10.1002/j.1538-7305.1946.tb03616.x

http://onlinelibrary.wiley.com/doi/10.1002/bltj.1946.25.issue-3/issuetoc



Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/27/2015 04:05 AM
This is how EagleWorks measures Q:

To measure the resonant cavity’s loaded Q-Factor we simply use our Agilent FieldFox Vector Network Analyzer (VNA)’s S11 return loss function to determine the bandwidth of the resonant cavity’s -3.0 db points from the 0.0 dB reference, divide this bandwidth figure by the resonant frequency and then invert that number to get the loaded Q-Factor
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zen-in on 05/27/2015 04:38 AM
This is how EagleWorks measures Q:

To measure the resonant cavity’s loaded Q-Factor we simply use our Agilent FieldFox Vector Network Analyzer (VNA)’s S11 return loss function to determine the bandwidth of the resonant cavity’s -3.0 db points from the 0.0 dB reference, divide this bandwidth figure by the resonant frequency and then invert that number to get the loaded Q-Factor

Interesting.   That is not how Q is usually measured.  There is a formula for calculating the bandwith of a filter:

F(bw) = F0/Q       where F0 = the frequency the filter is tuned for and F(bw) = the bandwidth of the filter

This is not how Q is measured although it does result in a close approximation.  Example:  I purchased a 4-pole filter from K&L in 1996 to help mitigate an interference problem we had with a TDRSS uplink.   It had a passband of 5 MHz @ 2085 MHz.  Using this I can calculate the Q = 417.   K&L measured the Q = 400.  EW method is not very far off; nowhere near as far off as Yang's measurement that was discussed earlier.

Q is defined as:

Q =  2*Pi*(Energy Stored) /(Energy Dissipated per Cycle)

The usual way it is measured is to divide the bandwidth (as defined above) into the full height of the spectral peak.   There is a diagram and this method is discussed on the Wikipedia page for Bandwith - Q factor.
 http://en.wikipedia.org/wiki/Q_factor
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/27/2015 05:00 AM
Someone alerted me to these
http://www.ets-lindgren.com/pdf/3163.pdf
Got tinfoil?

...no, not the hat!
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Supergravity on 05/27/2015 05:19 AM
In Shawyers Flight Thruster test the reported max thrust achieved was around 170mN.

Here and as attached.
http://emdrive.com/flightprogramme.html

That is approx 17 gf. Is a bit over the weight of 2 x US dollar coins. If I put them in your outstretched palm, could you feel the weight? Sure it is not a kg but the level is significant and not what some mosquito produces when it lands on your arm.

Comment away but maybe first do a bit of homework on the reported experimental results from Shawyer and the Chinese.

I don't see any paper or report on an in-depth overview of his experiment, his method, his apparatus, his analysis, and his conclusions based on that. Also, data without any error bars is meaningless. Many of his conclusions are non-sequitur and he makes no attempt at justifying them, such as:

"Comparison of the rates of increase of thrust for the different spring constants, using pulsed input power, gave a clear proof that the thrust was produced by momentum transfer and was not due to any “undefined” spurious effect."

Where exactly is the data that gives such "clear proof" so we can judge for ourselves if his conclusion has any merit, and not simply because Shawyer says so? There are many other background effects that could explain away his anomalous results, but he is not exactly very forthcoming.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Supergravity on 05/27/2015 05:37 AM
There should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Secondly, if someone is trying to capitalize on pseudo-science, I feel scientists have a moral responsibility to inform people who otherwise wouldn't understand the underlying science behind a proposed device. Informing is all we can do, and in the end, if they want to throw their money at some fantasy, then that's their choice.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: mwvp on 05/27/2015 06:19 AM
I have an interesting question / thought experiment in need of some input.

Suppose we have a perfectly conducting cylinder and we inject microwaves into the side, at the center of the cylinder. Their momentum propagates equally in both directions and the reflections result in standing waves. At one end of the cylinder, there is a thin layer of water sealed behind glass which is transparent to microwaves. At the other end, there is a perfect reflector. Should there be NET thrust now? Energy is being used to heat the water on one side, while the other side is receiving all of the momentum that is reflected from it.

The answer is, momentum is NOT conserved in dissipative systems. There should be thrust in proportion to the amount of heat that can be absorbed by the water. It's heat capacity is not infinite so eventually the system becomes polarized, until the water is allowed to cool.

@Rodal mentioned making the cavity a one-way street. Another idea would be to make the frustum out of different metals. Having zinc at one end and copper at the other end will form a galvanic cell, but it also forms a crude diode! This makes it more difficult for current to flow in one direction vs the other direction in the frustum, accomplishing that goal. Different metals can also make it more or less dissipative at each end.

Todd

I see a few problems. Water has a high dielectric constant, typically around 80 for lower frequencies anyways, rendering it very relfective, not transparent. But lets say instead lossy-ferrite impregnated carbon fiber like they could use on a stealth aircraft. Yes, assymetrical thrust results and you've got a photon rocket. Shawyer's EM Drive proports to give you the cavity Q, many thousands of times more bang per photon.

There may be a significant problem with an EM Drive implementation, dissapating significant amounts of low-grade, non-incandescent heat in space.

But if heat dissipation isn't allowed, then I would say the systems capacity to dissipate heat has become saturated rather than polarized and inoperable.

As far as dissimilar metals and diodes, I don't think it would help. Then again, after just looking up Peltier effect on Wikipedia and having my brain glaze-over, who knows.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/27/2015 06:21 AM
My new paper appeared today on arxiv with the number 1505.06917 in gr-qc section. I attach here a version for this forum and the maple worksheet to work with (I used Maple 18). As you will notice, the effect due to gravity is really small making it ineffective to explain the thrust measurements by NASA, if confirmed. On the other side, it appears rather clear that it is possible, with an interferometer, to observe the space-time geometry inside a cavity, for a given energy density of the electromagnetic field, to deviate from perfect flatness. It would be enough to consider relevant these theoretical computations just for such a result. In this way, it is possible to do measurements to test Einstein's general relativity with a table-top device. This should be considered a possible breakthrough and NASA is the first to have realized this.

My view on all this matter remains somewhat skeptical but I am ready to change my mind if ever some sound repetitions of NASA's experiment will be realized and will go through a peer-reviewed journal. Presently, the error bar and the order of magnitude of the effect compete but the paper by NASA is the best accomplished report on these measurements seen so far.  It remains indisputable that the idea to put on a pendulum such a cavity to see if something moves it is a really smart one and never attempted before. This is science rather than an usual "ipse dixit" that a lot of scientists prefer today.

P.S: just change the extension of the Maple worksheet from .txt to .mw.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: mwvp on 05/27/2015 06:33 AM

Based on what I have learned, blasting away with a wide band magnetron into a low Q cavity may be a good option as it really reduces lost/NO thrust from being constantly off resonance with a high Q cavity.


After I read the measurement document, I also thought it wasn't even a well-played and plausable scam. But in my present understanding acceleration or mere vibration is necessary for forces to develop.

Acceleration causes the Q-multiplied energy spectra to spread for separation and sideband filtering. No acceleration, no separation and forces balance so no thrust.

Consequently, if it works and works like I understand, it will have the amazing property of negative-inertial resistance. In one direction, you push (accelerate) it, it pushes back harder. Flip the cone over, push on it and it feels lighter. Since nobody's hand is perfectly still, the cone would feel like its vibrating. The more nervous you are, the more nervous it is  ;D

A magnetron can be modeled as a negative-resistance device. A single port oscillator or with a circulator a dual-port amplifier. It will mode-lock in its tuning range. I'll have to think about how to model and simulate the system. Would be nice to have an account at a place with Comsol. Its going to take me a while to learn Meep.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/27/2015 07:08 AM
There should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Secondly, if someone is trying to capitalize on pseudo-science, I feel scientists have a moral responsibility to inform people who otherwise wouldn't understand the underlying science behind a proposed device. Informing is all we can do, and in the end, if they want to throw their money at some fantasy, then that's their choice.
Did you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: DIYFAN on 05/27/2015 07:17 AM
There should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Secondly, if someone is trying to capitalize on pseudo-science, I feel scientists have a moral responsibility to inform people who otherwise wouldn't understand the underlying science behind a proposed device. Informing is all we can do, and in the end, if they want to throw their money at some fantasy, then that's their choice.

As a tax-paying citizen of the U.S., I have a different perspective.  I have a problem with our government not allocating at least a small amount of funding to high-risk high-reward scientific endeavors, including such long-shots as the EM Drive.  In my experience--and I've been around awhile--those who nicely fit certain areas of research and experimentation into the convenient "pseudo-scientific" basket are either protecting turf or are innately close-minded.  This is particularly true when experimental evidence indicates there might be something interesting happening.  There are those who will refuse to gaze into the telescope because it simply does not fit their known models.  This is just as true today as it was anciently--and the stakes are probably just as high or higher. 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/27/2015 07:40 AM
Got up from falling asleep during a bad movie tonight and in my dream I'd built an EM Drive. What I found interesting is I put it in my chilled water hot tub. I laughed at the idea when I woke up but thinking about it might have some merits. It would be a good heat sink and a good way to measure thrust by water displacement or weight. Although you really need to find something other than a hot tub.
Shell
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: CW on 05/27/2015 07:43 AM
There should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Secondly, if someone is trying to capitalize on pseudo-science, I feel scientists have a moral responsibility to inform people who otherwise wouldn't understand the underlying science behind a proposed device. Informing is all we can do, and in the end, if they want to throw their money at some fantasy, then that's their choice.

As a tax-paying citizen of the U.S., I have a different perspective.  I have a problem with our government not allocating at least a small amount of funding to high-risk high-reward scientific endeavors, including such long-shots as the EM Drive.  In my experience--and I've been around awhile--those who nicely fit certain areas of research and experimentation into the convenient "pseudo-scientific" basket are either protecting turf or are innately close-minded.  This is particularly true when experimental evidence indicates there might be something interesting happening.  There are those who will refuse to gaze into the telescope because it simply does not fit their known models.  This is just as true today as it was anciently--and the stakes are probably just as high or higher.

Fact is, humans are no different from any other kind of animal. They instinctively protect their turf. While being mandatory to do so in free nature, I think this intrinsic behavior tends to generally hinder 'progress' in our complex societies. That in itself does not say whether the hindered 'progress' would improve conditions for the average populace or worsen them. 'Progress' can also mean you're standing on the edge of a cliff and make one more step forward.. . Or you could make 'progress' by further reducing civil rights and freedoms. It's complicated :) .

Relating to the argument about tax payer's money.. let's just appreciate the fact that the U.S. is willing to spend around 600 billion USD each year just for military - all tax payer's money. Could a tiny, tiny fraction of that insane amount of money be better spent on things like infrastructure, education and health? I think so. But I'm no american tax payer.. so what do I know :p . Maybe using a couple 10k USD for EM-drive research is too much for the poor tax payer, who already has to pony up ~600 billion USD each year for military. Oh well. Priorities.
:o
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Tetrakis on 05/27/2015 07:48 AM
No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Did you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.

Clearly many people are persuaded by the argument from authority on this subject because few have the technical skills required to evaluate the speculative theories proposed for the emdrive data. This is why convincing other posters one way or the other on whether the experimental effect exists is so difficult; the question is less about the data and more about what sources of information we trust.

While I am highly skeptical of the thrust data, which seems to suffer from experimental ambiguity and a very low signal-to-noise ratio, personal experience has taught me that the most interesting discoveries in science are rarely found where we expect to see them. Revolutions in science mostly come from serindipity; even if this work shows that efficient propellantless propulsion is a theoretical illusion, it is looking for measurable effects far from where most experimental eyes are focused. Perhaps if those working on the emdrive look intently enough, they will see something nobody expected.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/27/2015 08:08 AM
No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Did you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.

Clearly many people are persuaded by the argument from authority on this subject because few have the technical skills required to evaluate the speculative theories proposed for the emdrive data. This is why convincing other posters one way or the other on whether the experimental effect exists is so difficult; the question is less about the data and more about what sources of information we trust.

While I am highly skeptical of the thrust data, which seems to suffer from experimental ambiguity and a very low signal-to-noise ratio, personal experience has taught me that the most interesting discoveries in science are rarely found where we expect to see them. Revolutions in science mostly come from serindipity; even if this work shows that efficient propellantless propulsion is a theoretical illusion, it is looking for measurable effects far from where most experimental eyes are focused. Perhaps if those working on the emdrive look intently enough, they will see something nobody expected.
Discovery is a learning process and we all are learning here. I don't know what I'm seeing in the EM Cavity but I believe there has been enough empirical data generated from widely different test beds that it deserves a time of controlled testing with a highly accredited lab.
The scientists and engineers at NASA, a couple universities and a few individuals are doing just that  through rigorous testing and documentation.
I think there is something there we don't understand and I have no doubt we will find out the why and for me personally I hope it's good news.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/27/2015 08:10 AM

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Did you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.

Clearly many people are persuaded by the argument from authority on this subject because few have the technical skills required to evaluate the speculative theories proposed for the emdrive data. This is why convincing other posters one way or the other on whether the experimental effect exists is so difficult; the question is less about the data and more about what sources of information we trust.

While I am highly skeptical of the thrust data, which seems to suffer from experimental ambiguity and a very low signal-to-noise ratio, personal experience has taught me that the most interesting discoveries in science are rarely found where we expect to see them. Revolutions in science mostly come from serindipity; even if this work shows that efficient propellantless propulsion is a theoretical illusion, it is looking for measurable effects far from where most experimental eyes are focused. Perhaps if those working on the emdrive look intently enough, they will see something nobody expected.

My view is it may well turn out to be nothing but if we did miss something revolutionary because of institutional inertia then it would be unforgivable.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: CW on 05/27/2015 08:25 AM

No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science.

Did you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.

Clearly many people are persuaded by the argument from authority on this subject because few have the technical skills required to evaluate the speculative theories proposed for the emdrive data. This is why convincing other posters one way or the other on whether the experimental effect exists is so difficult; the question is less about the data and more about what sources of information we trust.

While I am highly skeptical of the thrust data, which seems to suffer from experimental ambiguity and a very low signal-to-noise ratio, personal experience has taught me that the most interesting discoveries in science are rarely found where we expect to see them. Revolutions in science mostly come from serindipity; even if this work shows that efficient propellantless propulsion is a theoretical illusion, it is looking for measurable effects far from where most experimental eyes are focused. Perhaps if those working on the emdrive look intently enough, they will see something nobody expected.

My view is it may well turn out to be nothing but if we did miss something revolutionary because of institutional inertia then it would be unforgivable.

Actually, the next bigger asteroid impact out of the blue might kill most complex lifeforms on this planet, including humans. I read that a big extinction sized impact is statistically overdue for a couple millions of years now. If we as a species don't even try to come up with something that allows easy leaving of this world's gravity well, we're dead meat. There's no way to tell for sure right now if things like propellantless space drives and warp fields are engineerable in this universe. But not even trying, knowing the factual danger of life being eradicated by a big chunk of rock from the solar system, also knowing such an event is more or less overdue, would be a sin that would be punished by death. We better get our obese asses up and do something to solve this problem.

My 2 cents
:)


P.S.: At least Elon Musk with his SpaceX company has realized the importance of having a backup of humanity and life in other places than Earth. We can only hope, that at least his company's efforts of creating a 10x..100x reusable rocket system comes to full fruition with all the enormous cost reductions. Even without EM-drives and warp field tech, there would then be a least a chance for backing up our civilization.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: A_M_Swallow on 05/27/2015 08:29 AM

There was no on-board propellant consumption:  http://www.k.u-tokyo.ac.jp/news/20100105press-e.html but Thrust was generated through the explosive expansion of the atmospheric air by microwave energy deposition at the focus of the microwave beam ( the air is heated up to 10,000 degrees Celsius very rapidly. Steady thrust can be generated by repetitively pulsed microwave irradiations.).

So, it wouldn't generate that amount of thrust force without atmospheric air  ;).


The EM Drive could end up with an aircraft mode and a space mode.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/27/2015 08:49 AM

Fact is, humans are no different from any other kind of animal. They instinctively protect their turf. While being mandatory to do so in free nature, I think this intrinsic behavior tends to generally hinder 'progress' in our complex societies. That in itself does not say whether the hindered 'progress' would improve conditions for the average populace or worsen them. 'Progress' can also mean you're standing on the edge of a cliff and make one more step forward.. . Or you could make 'progress' by further reducing civil rights and freedoms. It's complicated :) .

Relating to the argument about tax payer's money.. let's just appreciate the fact that the U.S. is willing to spend around 600 billion USD each year just for military - all tax payer's money. Could a tiny, tiny fraction of that insane amount of money be better spent on things like infrastructure, education and health? I think so. But I'm no american tax payer.. so what do I know :p . Maybe using a couple 10k USD for EM-drive research is too much for the poor tax payer, who already has to pony up ~600 billion USD each year for military. Oh well. Priorities.
:o

I was about to bring up exactly the same thing, but you were faster in putting it down.. :)

I think the majority of the people involved inhere ARE aware that this might turn out to be "bogus science" and remain skeptical, but at the same time there is the perception, based upon a few (questionable, i agree on that) tests/experiments, that there is indeed something going on. That perception alone should be enough to investigate it more in depth, both on the theoretical level as with experiments.

If it turns out to be nothing, well we can all move on to the next interesting thing.. that is what research is all about, no?
I do not see the point of waving a warning finger about how not to precede with this because it is all pseudo science. Considering the intellectual capacity demonstrated by individuals inhere, i do not doubt one moment that everybody remains skeptical. Yet the prospect of participating or sitting on the front row of what might be a new area in space exploration remains very exciting...

It is good to have opposing ideas and clashing visions, on condition you keep listening to each other and do not entrench in ideology wars. The thesis/anti thesis/synthesis principle usually yields good results and must say is one of the greatest achievements of this topic.
 This open source internet collaboration is really one of the finest examples of scientific and engineering collaboration, because with some small exceptions the collaboration stays polite and constructive.

Dismissing curiosity or suppressing the intention to investigate something odd, based upon notion that it should not be possible, well - let me use some strong words here - I find that a form of scientific fundamentalism.


Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/27/2015 11:50 AM
EM Drive under siege. Nothing less than Sean Carroll with this post (http://www.preposterousuniverse.com/blog/2015/05/26/warp-drives-and-scientific-reasoning/). In the comment area there is Steven Docker "explaining" why thrust is measured but this does not seem to apply to measures in vacuum by NASA. Don't give up.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: rfmwguy on 05/27/2015 12:14 PM

Dismissing curiosity or suppressing the intention to investigate something odd, based upon notion that it should not be possible, well - let me use some strong words here - I find that a form of scientific fundamentalism.

Congratulations to one of the best posts I've read in a while...well, almost as good as my tag line  ;)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 12:23 PM
EM Drive under siege. Nothing less than Sean Carroll with this post (http://www.preposterousuniverse.com/blog/2015/05/26/warp-drives-and-scientific-reasoning/). In the comment area there is Steven Docker "explaining" why thrust is measured but this does not seem to apply to measures in vacuum by NASA. Don't give up.


Quote from: Sean Carroll
And what do we have for our propellantless space drive? Hmm — not quite that. No refereed publications — indeed, no publications at all.

Factual correction:  Prof. Yang's papers (on her theoretical analysis and experimental measurements of the EM Drive) have been published in the peer-reviewed journal Acta Physica Sinica -Chinese Edition- (ACTA PHYS SIN-CH ED)

Quote from: Sean Carroll
So what we have is a situation where there’s a claim being made that is as extraordinary as it gets — conservation of momentum is being violated.

Incorrect. None of the EM Drive researchers in the US, UK and China have proposed that conservation of momentum is being violated.  They all  claim it does not (by different means).  So the proper response by Carroll should be that their explanations are non-viable.   As to whether space propulsion without on-board propellants is possible, the scientific answer is: definitely yes.  Besides the scientifically obvious answers of Solar Sails and electrodynamic tethers (based on external fields) we have photon rockets for example, as perfectly valid means of space propulsion that require no on-board propellant and yet do not violate the law of conservation of momentum.  Even just releasing thermal radiation (as in the Pioneer anomaly) is s perfectly valid means of space propulsion that requires no on-board propellant and yet do not violate the law of conservation of momentum.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/27/2015 12:27 PM
EM Drive under siege. Nothing less than Sean Carroll with this post (http://www.preposterousuniverse.com/blog/2015/05/26/warp-drives-and-scientific-reasoning/). In the comment area there is Steven Docker "explaining" why thrust is measured but this does not seem to apply to measures in vacuum by NASA. Don't give up.

As William Camden wrote in 1605.... "all the proofe of a pudding, is in the eating"   ;D

There can be several theoretical models formulated, if it doesn't fly as said it would, it is all for nothing...
As it is a serious struggle to come up with a coherent mathematical model, only a clear, irrefutable test will have the final word on this...
Hopefully in a few months time there will be enough data to either confirm or deny an EMdrive produces a thrust.

Looking forward to :
- Eagleworks test in July
- TheTraveller's test setup
- Shawyer's 2015 report on his supercooled EMdrive v2.0. I hope that this time, his report is a bit more then a marketing leaflet with (rather hollow) future projections...
- Iullian further testing
-  and a few other testers that hopefully catch up.

Let us say that by the end of the year we'll all know for sure if we've been wasting our time, in a pleasant way, or that indeed this NASA-forum turned out to be a main contributor for a new space exploration area...
Whatever the outcome.... exciting, no? 8)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/27/2015 12:29 PM
EM Drive under siege. Nothing less than Sean Carroll with this post (http://www.preposterousuniverse.com/blog/2015/05/26/warp-drives-and-scientific-reasoning/). In the comment area there is Steven Docker "explaining" why thrust is measured but this does not seem to apply to measures in vacuum by NASA. Don't give up.
Instead of behaving like a scientist and using his time to do research he writes a factually wrong piece:

Quote from: Sean Carroll
And what do we have for our propellantless space drive? Hmm — not quite that. No refereed publications — indeed, no publications at all.

Factual correction:  Prof. Yang's papers (on her theoretical analysis and experimental measurements of the EM Drive) have been published in the peer-reviewed journal Acta Physica Sinica -Chinese Edition- (ACTA PHYS SIN-CH ED)

Quote from: Sean Carroll
So what we have is a situation where there’s a claim being made that is as extraordinary as it gets — conservation of momentum is being violated.

Incorrect. None of the EM Drive researchers in the US, UK and China have proposed that conservation of momentum is being violated.  They all  claim it does not (by different means).  So the proper response by Carroll should be that their explanations are non-viable.   As to whether space propulsion without on-board propellants is possible, the scientific answer is: definitely yes.  Besides the scientifically obvious answers of Solar Sails and electrodynamic tethers (based on external fields) we have photon rockets for example, as perfectly valid means of space propulsion that require no on-board propellant and yet do not violate the law of conservation of momentum.  Even just releasing thermal radiation (as in the Pioneer anomaly) is s perfectly valid means of space propulsion that requires no on-board propellant and yet do not violate the law of conservation of momentum.

I tried to post a comment there with a link to NASA's paper but he just dismissed it. Very sad. Remember that he is the guy claiming that multiverse should be believed and we should modify the scientific method to accept this "reality". On the other side, he is a star and a professor at Caltech.

It is interesting to see that behaviors seen almost four centuries ago are repeating yet. Clerics are others now.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Giovanni DS on 05/27/2015 12:32 PM
I am still skeptical but should the EMDrive be validated in the future, it will be fun to see how quick people will jump on the bandwagon.

Anyway, what is happening here is interesting to watch regardless the outcome.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: rfmwguy on 05/27/2015 12:44 PM
(http://imgp0.en.makepolo.net/m/485/276/aca81ff1cf98f1189f0e52179407dfd4.jpg)

(http://3.imimg.com/data3/RB/KE/MY-2552216/concentric-reducer-500x500.jpg)

http://www.pipetubeflanges.com/fittings.html

Could not find the exact size, but the flanged reducer config looks very similar to 50 ohm rigid transmission line reducers.

EIA line sizes usually extend to 8 3/16 diameter for 50 & 75 ohms. I've heard of larger line sizes, but not common. Its a high power broadcast commodity: http://www.eriinc.com/Catalog/Transmission-Line/Rigid-Coaxial-Line/MACX850.aspx

Interestingly enough, the 8 3/16 line has an 11 inch flange adapter, close to Shawyers cavity diameter I believe:

Specifications:

Impedance: 50 ± 0.5 Ohm
Maximum Frequency: 580 MHz
Maximum Television Channel (US): 32
Velocity: 99.8 %
Peak Power: 2644 kW
Net Weight: 11.2 lbm/ft | 16.67 kg/m
Outer Conductor, Outer Diameter: 8.15 inch | 20.70 cm
Outer Conductor, Inner Diameter: 8 inch | 20.32 cm
Inner Conductor, Outer diameter: 3.468 inch | 8.81 cm
Inner Conductor, Inner Diameter: 3.38 inch | 8.59 cm
Flange, Outer Diameter:11 inch | 27.94 cm
EIA Standard: Yes
Bolt Circle, Diameter: 10.312 inch | 26.19 cm
Number of Bolts: 18
Bolt Size: 3/8 inch

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 12:45 PM
...

I tried to post a comment there with a link to NASA's paper but he just dismissed it. Very sad. Remember that he is the guy claiming that multiverse should be believed and we should modify the scientific method to accept this "reality". On the other side, he is a star and a professor at Caltech.

It is interesting to see that behaviors seen almost four centuries ago are repeating yet. Clerics are others now.
Let's see whether my answer stays or not:

Quote from: Rodal
J. Rodal says:
May 27, 2015 at 5:41 am
Not a well-researched piece:

Quote from: Sean Carroll
“And what do we have for our propellantless space drive? Hmm — not quite that. No refereed publications — indeed, no publications at all.”

Factually incorrect: Prof. Yang’s papers (on her theoretical analysis and experimental measurements of the EM Drive) have been published in the peer-reviewed journal Acta Physica Sinica -Chinese Edition- (ACTA PHYS SIN-CH ED)

Quote from: Sean Carroll
“So what we have is a situation where there’s a claim being made that is as extraordinary as it gets — conservation of momentum is being violated.”

Incorrect. None of the EM Drive researchers in the US, UK and China have proposed that conservation of momentum is being violated. They all claim it does not (with different explanations). So the proper critique should be, instead, that their (different from each other) theoretical explanations are non-viable, and showing why they are non-viable. For example, if somebody claims as an explanation that they are using the Quantum Vacuum as something to push on, the critique should be that the Quantum Vacuum is frame-less, immutable and non-degradable, instead of writing that the authors are proposing that conservation of momentum is violated.

As to whether space propulsion without on-board propellants is possible, the obvious scientific answer is: yes. Besides the scientifically obvious answers of Solar Sails and electrodynamic tethers (based on external fields) we have photon rockets for example, as perfectly valid means of space propulsion that require no on-board propellant and yet do not violate the law of conservation of momentum. Even just releasing thermal radiation (as in the Pioneer anomaly) is s valid (albeit extremely low thrust) means of space propulsion that requires no on-board propellant and yet does not violate the law of conservation of momentum.

So, again, there is a (self-admitted) failure to examine what is being criticized, it is criticized on the wrong premise (that the authors claim that they don’t care about conservation of momentum, instead of criticizing their different conjectures to satisfy conservation of momentum), it advances a wrong, broadly-stated premise (that there cannot be propellant-less propulsion, which is false: Solar Sails, ElectroDynamic Tethers, Photon Rockets, Thermal Radiation, etc.) and it claims that none of this research has been published in peer-reviewed journals, thus ignoring the Chinese authors publications (which instead should be criticized based on their theoretical and experimental results).

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: marshallC on 05/27/2015 01:25 PM

Based on what I have learned, blasting away with a wide band magnetron into a low Q cavity may be a good option as it really reduces lost/NO thrust from being constantly off resonance with a high Q cavity.


After I read the measurement document, I also thought it wasn't even a well-played and plausable scam. But in my present understanding acceleration or mere vibration is necessary for forces to develop.

Acceleration causes the Q-multiplied energy spectra to spread for separation and sideband filtering. No acceleration, no separation and forces balance so no thrust.

Consequently, if it works and works like I understand, it will have the amazing property of negative-inertial resistance. In one direction, you push (accelerate) it, it pushes back harder. Flip the cone over, push on it and it feels lighter. Since nobody's hand is perfectly still, the cone would feel like its vibrating. The more nervous you are, the more nervous it is  ;D

A magnetron can be modeled as a negative-resistance device. A single port oscillator or with a circulator a dual-port amplifier. It will mode-lock in its tuning range. I'll have to think about how to model and simulate the system. Would be nice to have an account at a place with Comsol. Its going to take me a while to learn Meep.

My memory could be incorrect, but I believe this behavior was suggested earlier in thread 2. It might be worth looking back into that thread to see if some of the things said there could help you.

If this is the case, perhaps we should give emdrives a tap? Maybe we can ask Iulian to hit his with a stick from a safe distance while it is on? (Or, maybe slightly more scientifically, place and then remove a weight on the drive and test whether the thrust measured changes.)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: rfmwguy on 05/27/2015 01:30 PM
FYI...

"MAY 6, 2015
Cannae has embarked on next generation prototype testing and development.  We have our new numerical lab up and running and we will be moving into a new HQ facility and research lab in June 2015.  Stay tuned for big news!" - http://cannae.com/updates




Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/27/2015 01:33 PM
Criticism and Ego, it's all ego driven and a very good way to split the ranks into my team your vs team. We have fine tuned that trait for millions of years years. It's how and who we are. If you want I'll link publications.

He gains credibility in saying it's bunk and if it indeed turns out bunk he running around saying I told you so, if it works he say's that's interesting and a good thing... he is loosing nothing and gaining mass. Shouldn't that be a violation of something?

People in authority and respected positions do this all the time and we see it with politicians denying climate change. I'm no scientist or engineer but, I can gain your respect in dissing something you know little about. Tesla ran into the same problems with Edison who lead a campaign to the point of frying elephants with AC saying it was a bad idea.

My thought on this?  Mother Nature made the rules not man (or woman) and Mother Nature can break out rules if she so desires. It may not be so but we cannot be so egotistical to believe we know it all.

So don't get your panties in a wad, it's who we are,  just let grit your teeth and use it to drive and focus your dreams.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: CW on 05/27/2015 01:45 PM
FYI...

"MAY 6, 2015
Cannae has embarked on next generation prototype testing and development.  We have our new numerical lab up and running and we will be moving into a new HQ facility and research lab in June 2015.  Stay tuned for big news!" - http://cannae.com/updates

Let's just hope that the news resonant cavity does not thermally detune by hot air being produced inside the cavity, so that there won't by any measurable news due to news cutoff frequency kicking in.
;D
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/27/2015 01:48 PM
.... Shawyer's EM Drive proports to give you the cavity Q, many thousands of times more bang per photon.


What the experimental data shows is that it doesn't. It gives you less than Q x momentum/photon, per bang. It stores them up and lets them go all at once. It cannot operate continuously at Q*Power in. That would violate CoE.

Todd
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/27/2015 02:00 PM
Not to many years ago I remember sitting in a meeting with the best and finest from Intel (Emerging Technologies group) presenting a new fundamental way to separate the die on Si or GaS wafers. They brought out an Elephant and tried to fry him on the table, not really but it felt that way. The group leader (and a respected scientist) of the group said he couldn't understand how it worked, so it simply couldn't. They didn't buy the technology but it yanked my chain so bad that I sent them a 100mm inch wafer with  500 micron (about 30,000 chips) separated square dies as a present.

So if someone can't understand how something works it doesn't mean it can't, it means they don't understand and that fact makes them afraid, afraid of what they don't know.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 02:07 PM
I've been talking with Roger Shawyer and Paul March to try to obtain for EW, the SPR FLight Thruster for them to test. Dr White did contact Boeing about this but Boeing are not interested in loaning EW their test device.

As part of this conversation, I learned EW had a copy of the report Roger Shawyer sent to the UK gov about his results with the 1st Experimental device. He has agreed that I can share the conclusions with the forum. As attached.

Additionally Roger Shawyer has offered EW access to all his findings. I have asked Paul March to follow this up. Bolding is mine.

As an engineer I HATE reinventing the wheel.

Quote
Hi Traveller,

Thank you (and Paul) for the updates.

I guess the report you are referring to is the one we issued to the UK government in September 2002. This was very early work and is now outdated. However I have attached a scan of the conclusions which you may wish to share on your thread. Note that the experimental thruster was designed with a dielectric section to increase the guide wavelength at the small end. This also had the effect of decreasing the Q which led to the low thrusts we measured. All subsequent designs by ourselves and the other research groups we support have used non dielectric designs to ensue high Q values.

All our work since then has been documented in a similar style and issued to government and commercial customers including Boeing. If NASA has access to these documents then I find it extraordinary that they should continue with their QV theories. If they do not have this access then, if they send me a formal request, I will try to arrange it for them.

Best regards

Roger

I suggest this offer by Roger Shawyer, to allow EW access to his research findings, is very generous and a genuine effort to eliminate doubt, hand over solid test data and procedures that should accelerate EW's efforts to see 200mN and larger thrust levels.

I would also point out that replicators working with dielectrics should respect Roger's advice and leave them in the past and go for high Q cavities.

When Roger talks about "Cooling Air" that is hot air leaving the cavity, which cools the cavity.

Please note this report is 13 years old.

PIctures of the test device and the balance beam test setup are attached.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: CW on 05/27/2015 02:10 PM
Not to many years ago I remember sitting in a meeting with the best and finest from Intel (Emerging Technologies group) presenting a new fundamental way to separate the die on Si or GaS wafers. They brought out an Elephant and tried to fry him on the table, not really but it felt that way. The group leader (and a respected scientist) of the group said he couldn't understand how it worked, so it simply couldn't. They didn't buy the technology but it yanked my chain so bad that I sent them a 100mm inch wafer with  500 micron (about 30,000 chips) separated square dies as a present.

So if someone can't understand how something works it doesn't mean it can't, it means they don't understand and that fact makes them afraid, afraid of what they don't know.

Fun fact:
More often than not, when someone tells you "You can't do this" or "This can't be done", they just tell you that they themselves can't do it. This becomes especially comedic when you already have physical proof it can be done. I guess we don't have airplanes, multi-GHz computers and can't analyze the human genome within a couple hours now. What a pity. An amazing world it would be!
:D
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 02:17 PM
I've been talking with Roger Shawyer and Paul March to try to obtain for EW, the SPR FLight Thruster for them to test. Dr White did contact Boeing about this but Boeing are not interested in loaning EW their test device.

As part of this conversation, I learned EW had a copy of the report Roger Shawyer sent to the UK gov about his results with the 1st Experimental device. He has agreed that I can share the conclusions with the forum. As attached...
Sorry, but I only see the final conclusions of the report.  The "meat" of the report is missing.  It goes against my academic training, professional and business experience to accept the conclusions of a report without being able to examine what is the evidence that the conclusions are based on.

I certainly would not invest  in a company, for example, by just being able to look at the conclusions of a report.  I understand that you may reply by stating that Mr. Shawyer does not have to release the "meat" of the report, nobody has asked him to do so. What I am stating is that without being able to see the evidence that the conclusions are based on, no business or technical person would automatically accept the conclusions.   :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 02:17 PM
As part of this conversation, I learned EW had a copy of the report Roger Shawyer sent to the UK gov about his results with the 1st Experimental device. He has agreed that I can share the conclusions with the forum. As attached.

Thanks Traveller.  Is there any chance that more than just the conclusions section of that report will be released anytime soon?

~Kirk

I'm working behind the scenes to get Roger and EW working together. As that seems to be starting to happen, at least between Roger and Paul, I expect more info to drop and if I can, will post it.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: VAXHeadroom on 05/27/2015 02:18 PM
Not to many years ago I remember sitting in a meeting with the best and finest from Intel (Emerging Technologies group) presenting a new fundamental way to separate the die on Si or GaS wafers. They brought out an Elephant and tried to fry him on the table, not really but it felt that way. The group leader (and a respected scientist) of the group said he couldn't understand how it worked, so it simply couldn't. They didn't buy the technology but it yanked my chain so bad that I sent them a 100mm inch wafer with  500 micron (about 30,000 chips) separated square dies as a present.

So if someone can't understand how something works it doesn't mean it can't, it means they don't understand and that fact makes them afraid, afraid of what they don't know.

Fun fact:
More often than not, when someone tells you "You can't do this" or "This can't be done", they just tell you that they themselves can't do it. This becomes especially comedic when you already have physical proof it can be done. I guess we don't have airplanes, multi-GHz computers and can't analyze the human genome within a couple hours now. What a pity. An amazing world it would be!
:D

I work for a defense contractor and last year got to show a device for which I have been awarded a patent to a vice president of my company.  He told me I would never be successful because I wasn't working for a specific competitor (who makes similar devices).
We flew the device and successfully tested it on NASA's Zero-G airplane flights last summer :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 02:22 PM
Sorry, but I only see the final conclusions of the report.  The "meat" of the report is missing.  It goes against my academic training, professional and business experience to accept the conclusions of a report without being able to examine what is the evidence that the conclusions are based on.

I certainly would not invest  in a company, for example, by just being able to look at the conclusions of a report.  I understand that you may reply by stating that Mr. Shawyer does not have to release the "meat" of the report, nobody has asked him to do so. What I am stating is that without being able to see the evidence that the conclusions are based on, no business or technical person would automatically accept the conclusions.   :)

I agree but then no one is asking anybody to invest in SPR.

What Roger did share is more than we had before. As he has openly agreed to share data with EWs, lets hope they take him up on the offer and end up with non dielectric EW test devices producing 200+mN of thrust as then it is all over. Well not all over for the theory guys. But for us engineer replicators, garage DIY EM Drives will start being built all over the planet.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: birchoff on 05/27/2015 02:32 PM
Sorry, but I only see the final conclusions of the report.  The "meat" of the report is missing.  It goes against my academic training, professional and business experience to accept the conclusions of a report without being able to examine what is the evidence that the conclusions are based on.

I certainly would not invest  in a company, for example, by just being able to look at the conclusions of a report.  I understand that you may reply by stating that Mr. Shawyer does not have to release the "meat" of the report, nobody has asked him to do so. What I am stating is that without being able to see the evidence that the conclusions are based on, no business or technical person would automatically accept the conclusions.   :)

I agree but then no one is asking anybody to invest in SPR.

What Roger did share is more than we had before. As he has openly agreed to share data with EWs, lets hope they take him up on the offer and end up with non dielectric EW test devices producing 200+mN of thrust as then it is all over. Well not all over for the theory guys. But for us engineer replicators, garage DIY EM Drives will start being built all over the planet.

While I agree that no one is asking anyone to invest in SPR. I believe the intent of Rodal's comment was there was an expectation of their being more information in what you attached than what was found. That said the question I have for the theoreticians on the thread is; Does the conclusions provide any additional "useful" information?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 02:37 PM
Sorry, but I only see the final conclusions of the report.  The "meat" of the report is missing.  It goes against my academic training, professional and business experience to accept the conclusions of a report without being able to examine what is the evidence that the conclusions are based on.

I certainly would not invest  in a company, for example, by just being able to look at the conclusions of a report.  I understand that you may reply by stating that Mr. Shawyer does not have to release the "meat" of the report, nobody has asked him to do so. What I am stating is that without being able to see the evidence that the conclusions are based on, no business or technical person would automatically accept the conclusions.   :)

I agree but then no one is asking anybody to invest in SPR.

What Roger did share is more than we had before. As he has openly agreed to share data with EWs, lets hope they take him up on the offer and end up with non dielectric EW test devices producing 200+mN of thrust as then it is all over. Well not all over for the theory guys. But for us engineer replicators, garage DIY EM Drives will start being built all over the planet.

While I agree that no one is asking anyone to invest in SPR. I believe the intent of Rodal's comment was there was an expectation of their being more information in what you attached than what was found. That said the question I have for the theoreticians on the thread is; Does the conclusions provide any additional "useful" information?

I'm told EW has the full report. I did ask for it to be released. Was told SPR marked it Confidential, so EWs can't release it without SPR's approval. I then asked Roger for the report and he provided the conclusions I have shared. If more info comes to light, that I can share, it will be shared.

Was told that reading the full report, the thrust signatures are very strong and clear and that EW only disagreed with the theory presented.

Roger also told me of the 5 magnetrons used, he burnt out 3 and burns holes in waveguides. So there is danger here.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/27/2015 02:46 PM
Sorry, but I only see the final conclusions of the report.  The "meat" of the report is missing.  It goes against my academic training, professional and business experience to accept the conclusions of a report without being able to examine what is the evidence that the conclusions are based on.

I certainly would not invest  in a company, for example, by just being able to look at the conclusions of a report.  I understand that you may reply by stating that Mr. Shawyer does not have to release the "meat" of the report, nobody has asked him to do so. What I am stating is that without being able to see the evidence that the conclusions are based on, no business or technical person would automatically accept the conclusions.   :)

I agree but then no one is asking anybody to invest in SPR.

What Roger did share is more than we had before. As he has openly agreed to share data with EWs, lets hope they take him up on the offer and end up with non dielectric EW test devices producing 200+mN of thrust as then it is all over. Well not all over for the theory guys. But for us engineer replicators, garage DIY EM Drives will start being built all over the planet.

While I agree that no one is asking anyone to invest in SPR. I believe the intent of Rodal's comment was there was an expectation of their being more information in what you attached than what was found. That said the question I have for the theoreticians on the thread is; Does the conclusions provide any additional "useful" information?

No, nothing at all. The theory by Shawyer was debunked long ago and was one of the reasons why scientific community distrusted him. What is the date of this report? Has there been an update since the initial criticisms?

Seen in this way appears as nothing else than a generic list not even credible.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 02:53 PM
Sorry, but I only see the final conclusions of the report.  The "meat" of the report is missing.  It goes against my academic training, professional and business experience to accept the conclusions of a report without being able to examine what is the evidence that the conclusions are based on.

I certainly would not invest  in a company, for example, by just being able to look at the conclusions of a report.  I understand that you may reply by stating that Mr. Shawyer does not have to release the "meat" of the report, nobody has asked him to do so. What I am stating is that without being able to see the evidence that the conclusions are based on, no business or technical person would automatically accept the conclusions.   :)

I agree but then no one is asking anybody to invest in SPR.

What Roger did share is more than we had before. As he has openly agreed to share data with EWs, lets hope they take him up on the offer and end up with non dielectric EW test devices producing 200+mN of thrust as then it is all over. Well not all over for the theory guys. But for us engineer replicators, garage DIY EM Drives will start being built all over the planet.

While I agree that no one is asking anyone to invest in SPR. I believe the intent of Rodal's comment was there was an expectation of their being more information in what you attached than what was found. That said the question I have for the theoreticians on the thread is; Does the conclusions provide any additional "useful" information?

No, nothing at all. The theory by Shawyer was debunked long ago and was one of the reasons why scientific community distrusted him. What is the date of this report? Has there been an update since the initial criticisms?

Seen in this way appears as nothing else than a generic list not even credible.

Should be more information shortly:
http://www.ibtimes.co.uk/nasa-validates-emdrive-roger-shawyer-says-aerospace-industry-needs-watch-out-1499141

Quote
Shawyer says he has written a new paper about developers with second-generation EmDrive that is in the process of being peer reviewed but should make an appearance sometime in 2015.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: rfmwguy on 05/27/2015 03:05 PM
(...)

 But for us engineer replicators, garage DIY EM Drives will start being built all over the planet.

DIY EMers should view this short youtube vid: https://www.youtube.com/watch?v=I2k2g00onL0

Basically, a 2,000 volt transformer then goes into a doubler making the necessary 4,000 volts for a run of the mill magnetron. This is lethal voltage along with the necessary amperage to assure it. Biggest word here is DO NOT use a DVM or analog meter to measure this voltage. Stay away from it. Be very afraid...there's a reason.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/27/2015 03:06 PM
Please be careful with that last link as it got flagged by my Kaspersky anti virus...
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zen-in on 05/27/2015 03:07 PM
Sorry, but I only see the final conclusions of the report.  The "meat" of the report is missing.  It goes against my academic training, professional and business experience to accept the conclusions of a report without being able to examine what is the evidence that the conclusions are based on.

I certainly would not invest  in a company, for example, by just being able to look at the conclusions of a report.  I understand that you may reply by stating that Mr. Shawyer does not have to release the "meat" of the report, nobody has asked him to do so. What I am stating is that without being able to see the evidence that the conclusions are based on, no business or technical person would automatically accept the conclusions.   :)

I agree but then no one is asking anybody to invest in SPR.

What Roger did share is more than we had before. As he has openly agreed to share data with EWs, lets hope they take him up on the offer and end up with non dielectric EW test devices producing 200+mN of thrust as then it is all over. Well not all over for the theory guys. But for us engineer replicators, garage DIY EM Drives will start being built all over the planet.

While I agree that no one is asking anyone to invest in SPR. I believe the intent of Rodal's comment was there was an expectation of their being more information in what you attached than what was found. That said the question I have for the theoreticians on the thread is; Does the conclusions provide any additional "useful" information?

No, nothing at all. The theory by Shawyer was debunked long ago and was one of the reasons why scientific community distrusted him. What is the date of this report? Has there been an update since the initial criticisms?

Seen in this way appears as nothing else than a generic list not even credible.

Should be more information shortly:
http://www.ibtimes.co.uk/nasa-validates-emdrive-roger-shawyer-says-aerospace-industry-needs-watch-out-1499141

Quote
Shawyer says he has written a new paper about developers with second-generation EmDrive that is in the process of being peer reviewed but should make an appearance sometime in 2015.

Your persistant reposting of Shawyer's claims and photo-ops without any data to back up his claims constitutes forum spam.   Every page is filled with the same photos posted again and again and claims that Shawyer "is just on the verge of releasing some important information that will validate his previous claims" or statements to that effect.   Where is the data to support his conclusions?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/27/2015 03:17 PM

Sorry, but I only see the final conclusions of the report.  The "meat" of the report is missing.  It goes against my academic training, professional and business experience to accept the conclusions of a report without being able to examine what is the evidence that the conclusions are based on.

I certainly would not invest  in a company, for example, by just being able to look at the conclusions of a report.  I understand that you may reply by stating that Mr. Shawyer does not have to release the "meat" of the report, nobody has asked him to do so. What I am stating is that without being able to see the evidence that the conclusions are based on, no business or technical person would automatically accept the conclusions.   :)

I agree but then no one is asking anybody to invest in SPR.

What Roger did share is more than we had before. As he has openly agreed to share data with EWs, lets hope they take him up on the offer and end up with non dielectric EW test devices producing 200+mN of thrust as then it is all over. Well not all over for the theory guys. But for us engineer replicators, garage DIY EM Drives will start being built all over the planet.

While I agree that no one is asking anyone to invest in SPR. I believe the intent of Rodal's comment was there was an expectation of their being more information in what you attached than what was found. That said the question I have for the theoreticians on the thread is; Does the conclusions provide any additional "useful" information?

No, nothing at all. The theory by Shawyer was debunked long ago and was one of the reasons why scientific community distrusted him. What is the date of this report? Has there been an update since the initial criticisms?

Seen in this way appears as nothing else than a generic list not even credible.

Should be more information shortly:
http://www.ibtimes.co.uk/nasa-validates-emdrive-roger-shawyer-says-aerospace-industry-needs-watch-out-1499141

Quote
Shawyer says he has written a new paper about developers with second-generation EmDrive that is in the process of being peer reviewed but should make an appearance sometime in 2015.

Your persistant reposting of Shawyer's claims and photo-ops without any data to back up his claims constitutes forum spam.   Every page is filled with the same photos posted again and again and claims that Shawyer "is just on the verge of releasing some important information that will validate his previous claims" or statements to that effect.   Where is the data to support his conclusions?

He's already explained that in the posts above that.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: wallofwolfstreet on 05/27/2015 03:50 PM
I am very surprised by those poll results.  Based on those results, where individuals who feel their is propellantless thrust are slightly more numerous than those who claim no thrust, implies that the general consensus places the odds of their being a genuine, previously unknown//non-classical force at about 50% (ignoring all the people who don't have an opinion).

I find that to be an extremely high estimate given everything we have seen so far.  Yes, their have been replications, but this isn't a result that can easily be validated.  Lots of hard to control for confounding factors, and  it's a huge claim being made. 

I would have put the odds at somewhere in the 2-3% range.  Maybe 5% if I was feeling optimistic.  Interesting to learn that the forum overall is leaning to a much greater likelihood.  Just my two cents.


Edit:  Here is the link to the poll:  http://forum.nasaspaceflight.com/index.php?topic=37644.0
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kml on 05/27/2015 04:09 PM
For the Eagleworks team: do you report the net RF power entering the resonator (forward - reflected at feedpoint)?  Or total PA output?

For example in this picture ~50w is listed:

(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=814655;image)

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kdhilliard on 05/27/2015 04:10 PM
Should be more information shortly:
http://www.ibtimes.co.uk/nasa-validates-emdrive-roger-shawyer-says-aerospace-industry-needs-watch-out-1499141

Quote
Shawyer says he has written a new paper about developers with second-generation EmDrive that is in the process of being peer reviewed but should make an appearance sometime in 2015.
That should be interesting to see.  I predict that if it is truly peer reviewed (and not simply an unreviewed conference paper), then it will contain no theory but will instead only describe his test regime and results because there is no way that a competent reviewer would give a pass to Shawyer's action-reaction verbal gymnastics by which he argues that a net force which favors the interior surface of the large end plate somehow causes the drive to accelerate small end first.

I also predict (though with much less confidence) that if he does fully describe his test rig, it will be considerably more convoluted than the simple balances proposed here.  His measurement paper (http://www.emdrive.com/EmDriveForceMeasurement.pdf)'s "any attempt to measure them [thrust and reaction force] by simply placing the thruster vertically on a set of scales will fail." and "In each successful case [where forces have been measured], the EmDrive force data has been superimposed on an increasing or decreasing background force, generated by the test equipment itself." strongly suggests that his rigs contain additional sources of force, and that the EmDrive thrust signature must be extracted from a baseline signal via methods which are open to misinterpretation.

~Kirk
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 04:17 PM
...

The answer is, momentum is NOT conserved in dissipative systems. There should be thrust in proportion to the amount of heat that can be absorbed by the water. It's heat capacity is not infinite so eventually the system becomes polarized, until the water is allowed to cool.

@Rodal mentioned making the cavity a one-way street. Another idea would be to make the frustum out of different metals. Having zinc at one end and copper at the other end will form a galvanic cell, but it also forms a crude diode! This makes it more difficult for current to flow in one direction vs the other direction in the frustum, accomplishing that goal. Different metals can also make it more or less dissipative at each end.

Todd

Todd, have you had a chance to read Aquino's (*) paper (  https://hal.archives-ouvertes.fr/hal-01074608/document ) that I mentioned in my prior post ( http://forum.nasaspaceflight.com/index.php?topic=37642.msg1380265#msg1380265 )?

Remember that Shawyer analyzes the EM Drive cavity as two completely disjointed, discontinuous waveguides: One waveguide having the diameter of the Big end and the other waveguide having the diameter of the Small end.

Aquino goes one step further: he considers the Power dissipated at the Small end to be different than the Power dissipated at the Big end (and indeed we know that the power is dissipated unequally at the ends of the real continuous EM Drive).  What do you think of this approach and its consequences as analyzed by Aquino ?

Force = (PowerDissBigEnd*RefrIndexBigEnd - PowerDissSmallEnd*RefrIndexSmallEnd)/c

That's why we always used a calibrated feedback force.

Notsosureofit, what do you think of Aquino considering the different Power dissipated at both ends, vs. your formula?  Is your formula considering equal power dissipation at both ends?


(*) I have been made aware that Prof. Aquino has other out of the mainstream physics papers (concerning gravitational vs inertial mass), but the the purpose here is to address these equations solely based on their mathematical physics foundation and validity.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Taven on 05/27/2015 04:22 PM
For all the flack TheTraveller gets, even so much as being called a troll and spammer (funny considering what the rest of the internet would call a troll or spammer), he's the real MVP here. It doesn't matter who is right, or who is wrong, or if there is thrust, or if there is nothing. That will be resolved in time regardless of this thread. TheTraveller on the other hand is actually working to an end - talking directly with Shawyer and EW, working to get more information for everyone, and working to get EW and Shawyer - and everyone here - to work together. That's huge. That kind of action will resolve the questions around the device. (True or not!) That's measurable progress. The bickering and accusations in this thread, not so much.

And adding to this, I think everyone should show a little more kindness towards Shawyer. (Not to mention the other posters here) For one, he's a human being just like you and me. And secondly, regardless of outcome he's discovered something puzzling enough to stump the world and that alone deserves scientific respect.

On openness, do not fail to take the human element into your equations. Shawyer is very likely hesitant to cooperate openly because of the response he's gotten in the past to his work. People aren't just disagreeing with him, they're attacking him and dismissing him as a person. Try going decades being called a crackpot and getting personally torn to shreds in all forms of media anytime you spoke (even his eye contact in the interview was scrutinized and he was blamed for the questions he was asked!) and tell me if you'd be a social butterfly when people start finally looking at your work curiously. Put yourself in his shoes.

You aren't working with just numbers and data. You don't have to agree with his theory, just show him respect and remember there is a fellow human behind the work, just as there is a fellow human being behind the screen. We look to past scientists with such high regard, but utterly forget the personal hardships they went through to achieve what they did and we continue to inflict these hardships on current and future scientists again and again.

Show respect for your fellow scientists regardless of what they think. If everyone thought the same we wouldn't have science. We're all human beings in this together.

And for the love of Einstein please stop bickering over whether the device works or not, or whether the device should be investigated or not, or whether resources should be allocated to it or not. The thread here is to investigate, evaluate theories, and build the device regardless if it works or not. And as of right now, the ball is in the engineer's court.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Notsosureofit on 05/27/2015 04:42 PM

Notsosureofit, what do you think of Aquino considering the different Power dissipated at both ends, vs. your formula?  Is your formula considering equal power dissipation at both ends?

The formula that I've posted so far does not consider dissipation.  I should be able to get the same expression using the index-of-refraction formalism, but havn't done that.  I'm way behind on my slow reading.

*****************************************************************************
PS:  I'm looking for 1 more of these plates to complete the vacuum chamber for my "hoped for " experiment at X band.  Any leads followed (cheap that is) otherwise I'll have to make one, etc etc.  Remote switch for the Cavendish is in.  No perfect cavity yet.

https://www.dropbox.com/s/5rrpzvdwkwq9r11/IMAG0409.jpg?dl=0
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/27/2015 05:02 PM

Notsosureofit, what do you think of Aquino considering the different Power dissipated at both ends, vs. your formula?  Is your formula considering equal power dissipation at both ends?

The formula that I've posted so far does not consider dissipation.  I should be able to get the same expression using the index-of-refraction formalism, but havn't done that.  I'm way behind on my slow reading.

*****************************************************************************
PS:  I'm looking for 1 more of these plates to complete the vacuum chamber for my "hoped for " experiment at X band.  Any leads followed (cheap that is) otherwise I'll have to make one, etc etc.  Remote switch for the Cavendish is in.  No perfect cavity yet.

https://www.dropbox.com/s/5rrpzvdwkwq9r11/IMAG0409.jpg?dl=0
Would Stainless work? I have a chuck left over from my company that's about the same size. Let me dig it out from storage and take a few pics... if you can use stainless. You're quite welcome to it although it might need some lathe work.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: cometo on 05/27/2015 05:37 PM
Hi to everybody.

Are somebody thinking in putting a cloud chamber under the base of fustrum in order to check if charged particles are emitted?

If Emdrive were some kind of "vacuum particle extractor" this attachment should show that.

Regards.

https://www.youtube.com/watch?v=e3fi6uyyrEs
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/27/2015 05:45 PM

Notsosureofit, what do you think of Aquino considering the different Power dissipated at both ends, vs. your formula?  Is your formula considering equal power dissipation at both ends?

The formula that I've posted so far does not consider dissipation.  I should be able to get the same expression using the index-of-refraction formalism, but havn't done that.  I'm way behind on my slow reading.

*****************************************************************************
PS:  I'm looking for 1 more of these plates to complete the vacuum chamber for my "hoped for " experiment at X band.  Any leads followed (cheap that is) otherwise I'll have to make one, etc etc.  Remote switch for the Cavendish is in.  No perfect cavity yet.

https://www.dropbox.com/s/5rrpzvdwkwq9r11/IMAG0409.jpg?dl=0
Would Stainless work? I have a chuck left over from my company that's about the same size. Let me dig it out from storage and take a few pics... if you can use stainless. You're quite welcome to it although it might need some lathe work.
It's almost 14 inches across and the center area containing the concentric circles is 12 1/2.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 05:48 PM
Hi to everybody.

Are somebody thinking in putting a cloud chamber under the base of fustrum in order to check if charged particles are emitted?

If Emdrive were some kind of "vacuum particle extractor" this attachment should show that.
...
Great idea to look at convection currents when doing experiments in air.   Either natural convection currents produced by power dissipation at the EM Drive external surfaces or forced convection from heated moist air pressurized in its interior and leaving through gaps.   Something that researchers doing experiments in air can use to validate or nullify experimental explanations.  (Not so much for Quantum Vacuum as those are virtual particle pairs that have an ephemeral life governed by Heisenberg's uncertainty principle)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/27/2015 05:48 PM
I guess in a virtual world almost anything can be done. Found this interesting.
https://www.osapublishing.org/optica/fulltext.cfm?uri=optica-2-5-454&id=315920
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/27/2015 05:49 PM
.... Shawyer's EM Drive proports to give you the cavity Q, many thousands of times more bang per photon.


What the experimental data shows is that it doesn't. It gives you less than Q x momentum/photon, per bang. It stores them up and lets them go all at once. It cannot operate continuously at Q*Power in. That would violate CoE.

Todd
Sorry, but this is flat wrong.

For example, EW is running with approximately Q*P thrust for a continuous 20 seconds. And they are one of the examples of least thrust. Is 20 seconds long enough to disprove your conjecture? - I believe so. Numbers would be good though.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 05:53 PM
For all the flack TheTraveller gets, even so much as being called a troll and spammer (funny considering what the rest of the internet would call a troll or spammer), he's the real MVP here. It doesn't matter who is right, or who is wrong, or if there is thrust, or if there is nothing. That will be resolved in time regardless of this thread. TheTraveller on the other hand is actually working to an end - talking directly with Shawyer and EW, working to get more information for everyone, and working to get EW and Shawyer - and everyone here - to work together. That's huge. That kind of action will resolve the questions around the device. (True or not!) That's measurable progress. The bickering and accusations in this thread, not so much.

And adding to this, I think everyone should show a little more kindness towards Shawyer. (Not to mention the other posters here) For one, he's a human being just like you and me. And secondly, regardless of outcome he's discovered something puzzling enough to stump the world and that alone deserves scientific respect.

On openness, do not fail to take the human element into your equations. Shawyer is very likely hesitant to cooperate openly because of the response he's gotten in the past to his work. People aren't just disagreeing with him, they're attacking him and dismissing him as a person. Try going decades being called a crackpot and getting personally torn to shreds in all forms of media anytime you spoke (even his eye contact in the interview was scrutinized and he was blamed for the questions he was asked!) and tell me if you'd be a social butterfly when people start finally looking at your work curiously. Put yourself in his shoes.

You aren't working with just numbers and data. You don't have to agree with his theory, just show him respect and remember there is a fellow human behind the work, just as there is a fellow human being behind the screen. We look to past scientists with such high regard, but utterly forget the personal hardships they went through to achieve what they did and we continue to inflict these hardships on current and future scientists again and again.

Show respect for your fellow scientists regardless of what they think. If everyone thought the same we wouldn't have science. We're all human beings in this together.

And for the love of Einstein please stop bickering over whether the device works or not, or whether the device should be investigated or not, or whether resources should be allocated to it or not. The thread here is to investigate, evaluate theories, and build the device regardless if it works or not. And as of right now, the ball is in the engineer's court.

Thanks for the comments.

When I came on here I clearly said I would "Follow The Data, Theory Be Damned". I will continue to dig up the data and follow it where it leads me as I build my spreadsheet model of how the various alterable elements of an EM Drive relate to each other.

My goal is to replicate the narrow band high Q Flight Thruster. Was recently advise that may be a hard road to travel as the device has a very narrow bandwidth and resultant high Q for max thrust and is highly affected by thermal changes and Rf frequency drift.

Apparently EW, after trying that narrow band high Q pathway have now decided to go down the low Q, wide band magnetron pathway as is also followed by the Chinese.

As an engineer all this tells me we are dealing with a real device that has design and operational tradeoffs, exactly what I would expect of a real device.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 05:59 PM
.... Shawyer's EM Drive proports to give you the cavity Q, many thousands of times more bang per photon.


What the experimental data shows is that it doesn't. It gives you less than Q x momentum/photon, per bang. It stores them up and lets them go all at once. It cannot operate continuously at Q*Power in. That would violate CoE.

Todd
Sorry, but this is flat wrong.

For example, EW is running with approximately Q*P thrust for a continuous 20 seconds. And they are one of the examples of least thrust. Is 20 seconds long enough to disprove your conjecture? - I believe so. Numbers would be good though.

Give me another 6 weeks and I will have plenty of hard numbers for you and everybody else. Test runs will be streamed on YouTube and open to comments and discussion in real time. All data will be displayed in real time, logged and available for anyone to review.

My goal is to draw a line in the sand, stop the doubts and get on with developing a supportive theory from the experimental data.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 06:02 PM
.... Shawyer's EM Drive proports to give you the cavity Q, many thousands of times more bang per photon.


What the experimental data shows is that it doesn't. It gives you less than Q x momentum/photon, per bang. It stores them up and lets them go all at once. It cannot operate continuously at Q*Power in. That would violate CoE.

Todd
Sorry, but this is flat wrong.

For example, EW is running with approximately Q*P thrust for a continuous 20 seconds. And they are one of the examples of least thrust. Is 20 seconds long enough to disprove your conjecture? - I believe so. Numbers would be good though.
This is a better way to frame your question:

What are the conjectured time intervals necessary to

a) store the N*photon energy

and

b) let the N*photon momentum go. ?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 06:03 PM
Hi to everybody.

Are somebody thinking in putting a cloud chamber under the base of fustrum in order to check if charged particles are emitted?

If Emdrive were some kind of "vacuum particle extractor" this attachment should show that.
...
Great idea to look at convection currents when doing experiments in air.   Either natural convection currents produced by power dissipation at the EM Drive external surfaces or forced convection from heated moist air pressurized in its interior and leaving through gaps.   Something that researchers doing experiments in air can use to validate or nullify experimental explanations.  (Not so much for Quantum Vacuum as those are virtual particle pairs that have an ephemeral life governed by Heisenberg's uncertainty principle)

Shawyer covered that. See the sealed Faraday Cage around the 1st Experimental device. I really don't know why this is still being brought up. It was designed out of his 1st test protocol.

According to Shawyer, the thrust is not being caused by heated air nor radiated thermal energy nor ionic jets nor thermal expansion nor CG movement.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 06:08 PM
Hi to everybody.

Are somebody thinking in putting a cloud chamber under the base of fustrum in order to check if charged particles are emitted?

If Emdrive were some kind of "vacuum particle extractor" this attachment should show that.
...
Great idea to look at convection currents when doing experiments in air.   Either natural convection currents produced by power dissipation at the EM Drive external surfaces or forced convection from heated moist air pressurized in its interior and leaving through gaps.   Something that researchers doing experiments in air can use to validate or nullify experimental explanations.  (Not so much for Quantum Vacuum as those are virtual particle pairs that have an ephemeral life governed by Heisenberg's uncertainty principle)

Shawyer covered that. See the sealed Faraday Cage around the 1st Experimental device. I really don't know why this is still being brought up. It was designed out of his 1st test protocol.
I don't see anything there that can effectively eliminate natural and forced convection currents.
Aerodynamics shows that natural convection currents can exist in very confined spaces (thus the narrow gaps necessary for insulating glass panes in double-pane windows, for example).   It takes a very small, narrow gap of air to eliminate convection and favor conduction in air, as natural convection of a gas is always a preferred method of heat transfer than conduction (unless the air gap is very small).

The thrust is not being caused by heated air
I don't recall seeing any analysis proving that statement.  What I recall is @frobnicat posting a good analysis showing that air exhaust was a plausible explanation for the measured thrust.  Thus this possibility still remains open until proven otherwise. 

I am not saying that it has been proven that convection is an explanation for the thrust, or even addressing its Bayesian probability.  Just saying that the post from @cometo indicating how to show air convection currents is indeed a positive, helpful post, for experiments done in air, under ambient conditions.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 06:24 PM
I don't recall seeing any analysis proving that statement.  What I recall is @frobnicat posting a good analysis showing that air exhaust was a plausible explanation for the measured thrust.  Thus this possibility still remains open until proven otherwise. 

I am not saying it is an explanation, but the post indicating how to show air convection currents is indeed a positive post.

We have very little real data and that we do have has been data mined to death. So there is a lot of guesstimation. Shawyer has claimed hot air was controlled for and was not the cause of the thrust measured in his 1st experimental device. He claims 7 UK aerospace companies, microwave engineers and academics vetted the full reports data.

Would be nice to have that report. I'm working to make that happen.

In the Chinese devices, the test device movement is horizontal, so external rising hot air and internal buoyancy effects of heated air should have little effect on horizontal thrust. However CG movement, from thermal expansion could affect measured thrust as the device balances on a lower knife edge.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: rfmwguy on 05/27/2015 06:26 PM
@Rodal

Doc, thinking out loud here...might be tough to follow each new DIYEMer's latest updates buried in this thread. Is there a way to create new threads titled EM Drive Developments - Julian, Traveller, etc? Have a hunch we will be getting data at a pretty fast rate soon. This way, it consolidates specific replicator's efforts and gives them some kudos at the same time.

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/27/2015 06:28 PM
@Rodal: The net stored momentum of all cavity photons is zero, almost. There is a contribution from the source.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/27/2015 06:28 PM
@Rodal

Doc, thinking out loud here...might be tough to follow each new DIYEMer's latest updates buried in this thread. Is there a way to create new threads titled EM Drive Developments - Julian, Traveller, etc? Have a hunch we will be getting data at a pretty fast rate soon. This way, it consolidates specific replicator's efforts and gives them some kudos at the same time.

You can go to the members page and see all their postings and attachments.

As example for Mulletron:
http://forum.nasaspaceflight.com/index.php?action=profile;area=showposts;u=45378
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 06:33 PM
@Rodal

Doc, thinking out loud here...might be tough to follow each new DIYEMer's latest updates buried in this thread. Is there a way to create new threads titled EM Drive Developments - Julian, Traveller, etc? Have a hunch we will be getting data at a pretty fast rate soon. This way, it consolidates specific replicator's efforts and gives them some kudos at the same time.
As to the benefits of splitting the EM Drive thread, the last time we asked, at the end of the 2nd thread, the common wisdom was that the majority did not want to split the thread.  The argument was made that the benefit of having everybody in the same thread and thus creating synergy was far greater than the drawback of exponential growth of the thread and arguments between posters.

Arguments between posters, as long as they remain polite, and they concentrate on technical matters, are not to be seen as bickering, but on the contrary as a means to arrive at a common truth.  We can all learn from each other.

Division into small groups of people holding the same view, leads to group-think (http://en.wikipedia.org/wiki/Groupthink)


Quote
Group members try to minimize conflict and reach a consensus decision without critical evaluation of alternative viewpoints, by actively suppressing dissenting viewpoints, and by isolating themselves from outside influences.

Loyalty to the group requires individuals to avoid raising controversial issues or alternative solutions, and there is loss of individual creativity, uniqueness and independent thinking. The dysfunctional group dynamics of the "ingroup" produces an "illusion of invulnerability" (an inflated certainty that the right decision has been made). Thus the "ingroup" significantly overrates its own abilities in decision-making, and significantly underrates the abilities of its opponents (the "outgroup"). Furthermore groupthink can produce dehumanizing actions against the "outgroup".

Group-think has terrible consequences for innovation and R&D.  There is all kind of data showing that the most innovative research groups are composed of individuals with very different backgrounds.  It is their differences that fosters innovation.

Think of when we were children trying to figure out the world: how we explored everything and we were not afraid to ask questions.  Most scientists and engineers are the most creative and innovative when they are young.  Same with groups: having different people, and new people joining the forum with different viewpoints is actually a plus, although it may produce some self-questioning of held-beliefs and produce arguments.  Better than being fossilized into a common way of thinking assuming that everything has already been taken into account.


Please check with NSF site administrators, as I am not familiar with the latest rules on creating new threads.  The only thread I introduced at NSF was this 3rd thread as Chris warned that he had to close the 2nd thread because it was too long. :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: phaseshift on 05/27/2015 06:33 PM
I am very surprised by those poll results.  Based on those results, where individuals who feel their is propellantless thrust are slightly more numerous than those who claim no thrust, implies that the general consensus places the odds of their being a genuine, previously unknown//non-classical force at about 50% (ignoring all the people who don't have an opinion).

I find that to be an extremely high estimate given everything we have seen so far.  Yes, their have been replications, but this isn't a result that can easily be validated.  Lots of hard to control for confounding factors, and  it's a huge claim being made. 

I would have put the odds at somewhere in the 2-3% range.  Maybe 5% if I was feeling optimistic.  Interesting to learn that the forum overall is leaning to a much greater likelihood.  Just my two cents.


Edit:  Here is the link to the poll:  http://forum.nasaspaceflight.com/index.php?topic=37644.0

Not surprising considering the thread's demographic :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: bprager on 05/27/2015 07:12 PM
@Rodal

Doc, thinking out loud here...might be tough to follow each new DIYEMer's latest updates buried in this thread. Is there a way to create new threads titled EM Drive Developments - Julian, Traveller, etc? Have a hunch we will be getting data at a pretty fast rate soon. This way, it consolidates specific replicator's efforts and gives them some kudos at the same time.
Maybe a good idea to put the data on the wiki: http://emdrive.echothis.com/Experimental_Results, no?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/27/2015 07:14 PM
I finally  figured out how to make my microwave fly! Give a good solid kick!
But it doesn't fly very far, I think because the cord comes unplugged right away.

If you replicate my experience, be very careful, you could get hurt - I recommend combat boots.
Clearly you didn't put the right gravity warp virtual vacuum plasma magnetochiral floobie dust in it.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/27/2015 07:35 PM
@Rodal: The net stored momentum of all cavity photons is zero, almost. There is a contribution from the source.
was using WarpTech's statement << It stores them up and lets them go all at once. It cannot operate continuously at Q*Power in. That would violate CoE.>> to frame the question in terms of the time intervals that he conjectures for these processes to require, in order to address your prior point (does the data show that or not ?)

If the "net stored momentum of all cavity photons is zero, almost" that answers your question: as the time interval for storage is then practically zero, and not visible in the data charts.

You are not going to find "small fractions of a second" time bursts in 20 sec data that does not have that level of time discretization detail.

...For example, EW is running with approximately Q*P thrust for a continuous 20 seconds. And they are one of the examples of least thrust. Is 20 seconds long enough to disprove your conjecture? - I believe so. Numbers would be good though.
For the purposes of Todd's argument, we should be talking about stored energy and not stored momentum, since he explicitly mentions CoE. I recall calculating the stored energy a ways back to be substantially less than 1 Joule (if this forum had a half-decent search function, I'd quote the exact figure :(). I think it was Q*P/omega, so for EW that's roughly 6,000*85/(2*Pi*1.9e9) = 5e-5 J. Looks about right. How long does the input power take to accumulate that energy? t = 5e-5/85 = 0.5 usec.

I am pointing out that 20 seconds is substantially longer than 0.5 microseconds.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: tchernik on 05/27/2015 07:45 PM
I finally  figured out how to make my microwave fly! Give a good solid kick!
But it doesn't fly very far, I think because the cord comes unplugged right away.

If you replicate my experience, be very careful, you could get hurt - I recommend combat boots.

The best part is that your Microwave propulsion technology proposal is clearly propellentless, but not reactionless.

And we can be reasonably certain it respects both conservation of momentum and energy.  ;D
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/27/2015 07:48 PM
...For the purposes of Todd's argument, we should be talking about stored energy and not stored momentum, since he explicitly mentions CoE. I recall calculating the stored energy a ways back to be substantially less than 1 Joule (if this forum had a half-decent search function, I'd quote the exact figure :(). I think it was Q*P/omega, so for EW that's roughly 6,000*85/(2*Pi*1.9e9) = 5e-5 J. Looks about right. How long does the input power take to accumulate that energy? t = 5e-5/85 = 0.5 usec.

I am pointing out that 20 seconds is substantially longer than 0.5 microseconds.
Fair enough.  We agree on the possible time interval and that "stored energy" is the correct term to use.  WarpTech will answer for himself, but my interpretation (perhaps wrong ?) of what he was proposing is a series of very short time bursts (~ microseconds) that will not be visible in a 20 second long time chart. 

Therefore we cannot use the time charts to assess whether his model is correct or not.

Microsecond bursts would be  invisible in the time chart, since it does not have that kind of resolution, and I expect that NASA's Eagleworks torsion pendulum dynamics x(t) (being measured) would not show that kind of response to F(t):

m d2x/dt2 + c *dx/dt + K x = F(t)

where x is a rotational degree of freedom around the torsional axis, m is the moment of inertia, c is the damping and K is the torsional stiffness

microsecond bursts would get damped out, and the response governed by the pendulum dynamics. Which is what we see: a response (for NASA Eagleworks) that is governed by the pendulum dynamics, with some small amplitude noise on it (see my Autocorrelations and Power Spectral Density analysis of Eagleworks data earlier in the thread).
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/27/2015 07:49 PM
.... Shawyer's EM Drive proports to give you the cavity Q, many thousands of times more bang per photon.


What the experimental data shows is that it doesn't. It gives you less than Q x momentum/photon, per bang. It stores them up and lets them go all at once. It cannot operate continuously at Q*Power in. That would violate CoE.

Todd
Sorry, but this is flat wrong.

For example, EW is running with approximately Q*P thrust for a continuous 20 seconds. And they are one of the examples of least thrust. Is 20 seconds long enough to disprove your conjecture? - I believe so. Numbers would be good though.

Maybe my words are so elaborate this time, but all I am saying is a photon rocket has a thrust of,

F = dp/dt = P/c, P is power, p is momentum.

So far, all experiments show a thrust,

F < Q*P/c < Q*dp/dt

So it is not as efficient as a photon rocket of power Q*P. Sorry, I'm at lunch. Don't have time right now to work out a detailed duty cycle expression, but you get the picture.






Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: maciejzi on 05/27/2015 09:16 PM
Would it be possible to use magnetic forces (e.g. electromagnets) to capture the microwaves in the cavity for a longer period of time?

Maybe instead of extremely high Q cavities it would be easier to use electromagnets around the frustum to keep the microwaves inside and/or direct the microwaves in the required direction and/or slow them down as required?

I mean instead of superconducting frustum, which requires heavy cooling, it may be easier to achieve the required thrust by putting the frustum in electromagnetic trap or even to replace the copper walls with electromagnets and injecting the microwaves in such magnetic box?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: KittyMoo on 05/27/2015 10:09 PM
Would it be possible to use magnetic forces (e.g. electromagnets) to capture the microwaves in the cavity for a longer period of time?

Maybe instead of extremely high Q cavities it would be easier to use electromagnets around the frustum to keep the microwaves inside and/or direct the microwaves in the required direction and/or slow them down as required?

I mean instead of superconducting frustum, which requires heavy cooling, it may be easier to achieve the required thrust by putting the frustum in electromagnetic trap or even to replace the copper walls with electromagnets and injecting the microwaves in such magnetic box?
No
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: X_RaY on 05/27/2015 10:25 PM


Hello i am new in this forum. Based on my own simple model(flat end plates) the frequency has to be approximately 2.52GHz.
I hope this is helpfull :)

Hi, can you share your model?

Yes, its an simple libreoffice file. I use this to calculate resonance fequencys of shaped cone cavitys. Some days ago i implemented the trust/frequency things up to 30GHz based on a file of the forum "Shawyer Design Factor Frequency Scanner Version 2014 May 12 B.xls"
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/28/2015 01:58 AM
I think my point is being missed for the case of a completely static gas.
I've seen people arguing for a net nonzero force even in this case.
The reason for pointing this out is to make you think.
Point well taken.

It would be very useful to get strong skeptical reviews of Prof.Yang's paper ((translated) page 4 ( http://www.emdrive.com/NWPU2010translation.pdf  ) concerning her equations stating that having a gas/fluid with charged particles inside the EM Drive results in transfer of its momentum to the EM Drive metallic body. 

Just like the great job you did addressing energy conservation.

It seems to me that she also needs to take into account directional attenuation  in order to get a non-zero Poynting vector.

If you have a chance to look at her equations, I'll for one, would appreciate knowing what you think about them   :)
I tried. The formatting of the equations is execrable, but despite that and after reading all of it, and then realising that she was using Maxwell to produce evidence of an asymmetrical force, I knew the entire paper was wrong. The reason it's wrong is because group velocity is being conflated with phase velocity.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: PaulF on 05/28/2015 02:15 AM
(...)

 But for us engineer replicators, garage DIY EM Drives will start being built all over the planet.

DIY EMers should view this short youtube vid: [youtube]I2k2g00onL0[/youtube]

Basically, a 2,000 volt transformer then goes into a doubler making the necessary 4,000 volts for a run of the mill magnetron. This is lethal voltage along with the necessary amperage to assure it. Biggest word here is DO NOT use a DVM or analog meter to measure this voltage. Stay away from it. Be very afraid...there's a reason.
Very good point. Add that to the other warnings about magnetrons. The lethal current is considered to be from around 30mA. At 4 kV, your body and especially your skin WILL BE FRIED with a current of over 1.8 Amps! Now the coils to supply a 1 kW magnetron can't sustain that much current but the voltage will probably drop a good deal due to high load in order to sustain the maximum possible current. It's a killer, no doubt. It doesn't matter anymore if it's AC or DC - you're literally thunderstruck or better said, Lightningstruck ;)



May I suggest a subtopic aimed at laying out all dangers associated with the use of bare magnetron emitters or other dangerous high voltage/current/RF emitters? It should be advocated more seriously on this forum than has been till now. But that's just my opinion.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 02:17 AM
I think my point is being missed for the case of a completely static gas.
I've seen people arguing for a net nonzero force even in this case.
The reason for pointing this out is to make you think.
Point well taken.

It would be very useful to get strong skeptical reviews of Prof.Yang's paper ((translated) page 4 ( http://www.emdrive.com/NWPU2010translation.pdf  ) concerning her equations stating that having a gas/fluid with charged particles inside the EM Drive results in transfer of its momentum to the EM Drive metallic body. 

Just like the great job you did addressing energy conservation.

It seems to me that she also needs to take into account directional attenuation  in order to get a non-zero Poynting vector.

If you have a chance to look at her equations, I'll for one, would appreciate knowing what you think about them   :)
I tried. The formatting of the equations is execrable, but despite that and after reading all of it, and then realising that she was using Maxwell to produce evidence of an asymmetrical force, I knew the entire paper was wrong. The reason it's wrong is because group velocity is being conflated with phase velocity.
Thanks for taking the time to go through her paper.

When I first read it, a long time ago, I stopped reading it once I saw that she was using group velocity that way and that she was neglecting the forces on the side walls.

However, WarpTech brought to our attention that she does that only in the section of the paper titled  "Original idea of the microwave thruster without propellant" where she essentially repeats Shaywer's formulation.   However later on, she does take into account the stresses on the side walls. 

I just used the search function on my Adobe Professional and I could not find her using "group velocity" or "vg"  or "group" anywhere else but the section  "Original idea of the microwave thruster without propellant" or in her conclusions section where she quickly summarizes that the problem could have been approached another way, using group velocity.

Rather, she uses the Finite Element numerical solution of Maxwell's equations and calculates the Maxwell Stress Tensor components.

In her conclusions she states:

Quote
There are two ways to explain this new thrusters, (1) from the Plank’s hypothesis and Einstein’s quantum theory of light, also the theory of microwave to explain the thrust from the thrusters, that is to quantise the injected microwave to the sealed cavity into photons, its travelling speed is the group speed, photons and the thrust cavity wall elastic collision produce the net thrust, (2) From the classic theory of electrodynamics to explain how the thrust is produce by the thrusters, according to the kinetic energy and conservation of momentum of the electromagnetic system within its volume, Maxwell equation and electromagnetic flux density vector can found out the source of the thrust is coming from the integration of the electromagnetic tensor along the surface of the volume

Please note that she uses option #2 and not #1. For option #2 group velocity is not involved.

Could you please point out where else does she use the group velocity? (other than the section "Original idea of the microwave thruster without propellant" and the quick summary in the conclusions dealing with an alternative approach)

Thanks

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/28/2015 02:21 AM

Todd, have you had a chance to read Aquino's (*) paper (  https://hal.archives-ouvertes.fr/hal-01074608/document ) that I mentioned in my prior post ( http://forum.nasaspaceflight.com/index.php?topic=37642.msg1380265#msg1380265 )?

Remember that Shawyer analyzes the EM Drive cavity as two completely disjointed, discontinuous waveguides: One waveguide having the diameter of the Big end and the other waveguide having the diameter of the Small end.

Aquino goes one step further: he considers the Power dissipated at the Small end to be different than the Power dissipated at the Big end (and indeed we know that the power is dissipated unequally at the ends of the real continuous EM Drive).  What do you think of this approach and its consequences as analyzed by Aquino ?

Force = (PowerDissBigEnd*RefrIndexBigEnd - PowerDissSmallEnd*RefrIndexSmallEnd)/c

(...)

(*) I have been made aware that Prof. Aquino has other out of the mainstream physics papers (concerning gravitational vs inertial mass), but the the purpose here is to address these equations solely based on their mathematical physics foundation and validity.

I've always referred to him as De Aquino, so at first I didn't recognize the name. Anyway, he does what he always does. He takes a fairly good idea, makes grandiose claims and then butchers the theory. Without going into detail on how he meanders off into the QV without a clue, I will say he has the right idea about materials. Here's the gist of it;

Forget the Frustum for a moment. Suppose we have a solenoidal coil, say 1 meter long, a few inches in diameter. Say, PVC pipe wrapped in copper wire. It is now an Air Core inductor.

At one end, we plug the opening with a perfectly conducting disk. At the other end, we plug it with a perfect Ferromagnetic disk. As the current through the inductor is charging, imagine the Vector Potential field, "A(x,t), where x is along the length of the solenoid. EM momentum is Q*A, so A(x,t) will be proportional to momentum of the field. As the inductor charges, the "A" field, along with the coil will be pushed backwards, toward the magnetic end and repelled from the conductor end. Likewise, magnetic disk and the conducting disk will be pushed forward, in the same direction, toward the conductive end forward.

The conductive end is a "short circuit" on the coil, a perfect reflector. The magnetic end is an absorber, it stores energy without dissipation. In a system as I've described, even at 60Hz, the forces are not trivial. Failure of those forces to perfectly cancel each other out, may lead to a significant "thrust" without propellant.

Todd
 

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/28/2015 02:25 AM
Calculating Shawyer Demonstrator Df.

Shawyer's thrust equation T = (2 * Df * Po * Q) / c gives us the ability to calc Df, knowing Q, T & Po as Df = (c * T) / (2 * Po * Q)

Demonstrator EM Drive, published data:

Q: 45,000
Po: 334W
T: 0.096N

Therefore Df = 0.95714. This suggests Shawyer's reported Df of 0.844 is correct as effective Q at measured power may not be 45,000 due to thermal detuning or the magnetron frequency not being at cavity resonance.

When calculating the small end diameter, we must know the TEm,n or TMm,n excitation mode as the cutoff wavelength can vary quite a lot, which effects guide wavelengths Lambda g1 and Lambda g2 and thus Df. As we don't the mode, we must assume the Df of 0.844 is the correct value. A bit of playing with modes and trying different small end values may reveal the mode and true small end size.

Have fun.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/28/2015 02:38 AM
Quote from: WarpTech
The conductive end is a "short circuit" on the coil, a perfect reflector. The magnetic end is an absorber, it stores energy without dissipation. In a system as I've described, even at 60Hz, the forces are not trivial. Failure of those forces to perfectly cancel each other out, may lead to a significant "thrust" without propellant.
Why don't you build it and find out?

When you discover it doesn't work, you'll be a better theorist for the experience, because you will first have to discover and understand your error, and then you will never again repeat it.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 02:39 AM
Calculating Shawyer Demonstrator Df.

Shawyer's thrust equation T = (2 * Df * Po * Q) / c gives us the ability to calc Df, knowing Q, T & Po as Df = (c * T) / (2 * Po * Q)

Demonstrator EM Drive, published data:

Q: 45,000
Po: 334W
T: 0.096N

Therefore Df = 0.95714. This suggests Shawyer's reported Df of 0.844 is correct as effective Q at measured power may not be 45,000 due to thermal detuning or the magnetron frequency not being at cavity resonance.

...

The big problem with inverting any multivariable equation like Shawyer's equation where T is an unknown :

to get Df = (c * T) / (2 * Po * Q)

in terms of experimental values, is that such an inversion presumes that Df is a free parameter that can be forced to give any value of experimental value of thrust (*)

One could do that with any equation, we could put a free parameter in McCulloch's equations for example and match a given set of experimental values as well.

So, the right way to do this is not that way, but instead to have an expression for Df in terms of the geometry, and compute Df from the geometry, and then compare the predicted value of thrust force to experiments.

The problem is that using Df = 0.95714 gives a diameter for the small base that is way smaller than what the Demo picture shows, as previously discussed in this thread by @phaseshift, when using the lowest possible mode shape as the cut-off frequency. 

If the Design Factor is not expressed in terms of a defined cut-off frequency (like the lowest possible cut-off frequency) as we did in the previous pages, then the Design Factor is not a well-posed equation until it is defined what mode shape one is supposed to use for the cut-off frequency in the Design Factor.

As you said, then one can "have fun"

________

(*) I could write  an equation like this

PriceOfIBM[@9:30am] = temperature[@9:30am] * Df

now, give me the temperature at a future day and the [email protected]:30 that future day, and I can calculate Df ( $/share per deg C), so as to give the price of IBM exactly. 

Does that give me a value of Df that then I can use to predict the price of IBM stock the following day ? Of course not. The problem is that you are presuming that Shawyer's equation with an independently calculated Df prior to an experiment can predict the value of thrust you are going to get in all future experiments, for any value of P, Q and any geometry.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/28/2015 02:44 AM
Two comments: a) nothing here is worth more than 2 or 3 digits of precision, and b) Df does serve at least the purpose of bounding the thrust from above at the limiting value given by Df = 1.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/28/2015 02:51 AM
Calculating Shawyer Demonstrator Df.

Shawyer's thrust equation T = (2 * Df * Po * Q) / c gives us the ability to calc Df, knowing Q, T & Po as Df = (c * T) / (2 * Po * Q)

Demonstrator EM Drive, published data:

Q: 45,000
Po: 334W
T: 0.096N

Therefore Df = 0.95714. This suggests Shawyer's reported Df of 0.844 is correct as effective Q at measured power may not be 45,000 due to thermal detuning or the magnetron frequency not being at cavity resonance.

...

The big problem with inverting any multivariable equation like Shawyer's equation where T is an unknown :

to get Df = (c * T) / (2 * Po * Q)

in terms of experimental values, is that such an inversion presumes that Shawyer's equation can accurately predict experimental values to that level of accuracy.

In other words, Df is a free parameter that can be forced to give any value of experimental value of thrust.

One could do that with any equation, we could put a free parameter in McCulloch's equations for example and match a given set of experimental values as well.

So, the right way to do this is not that way, but instead to have an expression for Df in terms of the geometry, and compute Df from the geometry, and then compare the predicted value of thrust force to experiments.

The problem is that using Df = 0.95714 gives a diameter for the small base that is way smaller than what the Demo picture shows, as previously discussed in this thread by phase-shift

Df is affected by the guide wavelength,  which is affected by the cut-off wavelength, which is affected by both the diameter and the excitation mode.

If we don't know the excitation mode, we can't use the Df to reverse calc the small end diameter from the big.

Shawyer used 0.844 as the Demonstrator Df in many papers. I suggest it is correct.

Using the same Df calc method I get similar high Dfs for the Flight Thruster so I expect it's Df to also be high. There we know the excitation mode is TE013 & so can cross check with a forward Df calc as we know,  sort of, the internal dimensions.

I'll have more data on the Flight Thruster in a few days. Hopefully enough to place a laser cut order for the frustum.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/28/2015 03:00 AM
If the Design Factor is not expressed in terms of a defined cut-off frequency (like the lowest possible cut-off frequency) as we did in the previous pages, then the Design Factor is not a well-posed equation until it is defined what mode shape one is supposed to use for the cut-off frequency in the Design Factor.

As you said, then one can "have fun"

You can't calc guide wavelength, the basic of the Df equation, without knowing cut off wavelength, which depends on diameter and excitation mode. Excitation mode is at the heart of the Df equation, via its affect on cut off wavelength.

Without knowing excitation mode, doing reverse end plate sizes from the other end plate and Df is fruitless, unless you are on a fishing trip.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/28/2015 03:18 AM
From which we conclude, because 0 <= Df <= 1, that
0 <= F <= 2 Q P/c , where F is the thrust.

So with Df = 1 and even if Q =1, F is twice that which would be delivered by a photon rocket at power P. Sound right to you?

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Blaine on 05/28/2015 03:21 AM
i just looked at a critique based on the bayes outlook of emdrive and i can only say...bayes theorem is the dumbest thing i have ever heard of in my life.  i understand the math just fine.  its just so hand wavy abd full of hot air that i cant take the critism seriously at all.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/28/2015 03:30 AM
Quote from: WarpTech
The conductive end is a "short circuit" on the coil, a perfect reflector. The magnetic end is an absorber, it stores energy without dissipation. In a system as I've described, even at 60Hz, the forces are not trivial. Failure of those forces to perfectly cancel each other out, may lead to a significant "thrust" without propellant.
Why don't you build it and find out?

When you discover it doesn't work, you'll be a better theorist for the experience, because you will first have to discover and understand your error, and then you will never again repeat it.

First off, Yang's final equation for force is correct. She integrates the E and B pressures over all surfaces. She does not use group velocity, or phase velocity, but I did see the error you are referring to. It is irrelevant to the end result. Please show us the error? Maxwell's equations can predict the thrust perfectly well, if dissipation, attenuation, reflection, absorption and scattering are ALL taken into consideration accurately. Nobody has done that yet, but Yang's equation is the best approach if you have the software to crunch the integrals. Just plug in values of E and B that have amplitudes, phases, frequencies and time dependence on these factors, at all coordinates on the surface. Piece of cake! ;)

Given a system of 2 diametrically opposing forces, and all the variables we have at our disposal. Can we create a system that when it is charging or discharging, is mechanically off-balance and propagates forward? I already know this can be done, has been done and is being done because dissipative systems are not conservative. What remains to be determined is, how "should" we calculate it as engineers and how do we optimize it? Yang said;

Quote

The thrust curves demonstrate that on the surfaces of the ma- jor and the minor end plates, the magnetic thrust is two orders of magnitude higher than the electric thrust; on the surface of the side wall, the magnetic thrust is three times of the electric thrust;



This says the imbalance on just the end plates is 100X more significant than those on the sidewalls. So my thought experiment is optimizing that end of it, so to speak.  ;D

Maybe I will build one and test it, but I have 50 some odd solar projects to manage at the moment and no spare change. My spare time is mostly spent here, trying to keep up. LOL!
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/28/2015 03:44 AM
OK on the time issues! But my point is that no application of Maxwell, dissipative or not, should result in thrust greater than a photon rocket. Maxwell's stress tensor is well understood and if a calculation using it produces a thrust value greater than a photon rocket, then a mistake has been made. It is possible to say that with absolute certainty without actually identifying the error.

Furthermore, your mark-space ratio idea on Q*P with a duty cycle of 1:Q won't save you. You will also measure a time-averaged thrust value that is on order P/c, so everything comes out right. It does not explain how a time-averaged thrust of Q*P could be measured.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: zen-in on 05/28/2015 06:11 AM
I...
Point well taken.

It would be very useful to get strong skeptical reviews of Prof.Yang's paper ((translated) page 4 ( http://www.emdrive.com/NWPU2010translation.pdf  ) concerning her equations stating that having a gas/fluid with charged particles inside the EM Drive results in transfer of its momentum to the EM Drive metallic body. 
...

I was under the impression that Yang had built an EM drive and had done a series of experiments that showed it could produce a mN thrust.   There is no mention of any experiments or measurements in the above translated paper.   I'll have to tip my hat to whoever translated it.   A well done job.

So this is the problem I have with believing the EM-drive is not a hoax; or stated more politely a case of mistaken measurements.    In thread 2 I stated the EW thrust signatures were not consistent with the known step response of their torque pendulum.   The calibration pulse, generated by a capacitive device, always produced an underdamped response (thrust graph).   This is the response that anything that pushes on the cavity should produce.   If a moth flew at the cavity, this same step response would be seen.   This is an immutable physical observation of mechanical systems.  They all have a natural frequency and a damping coefficient.   Any perturbation will exhibit the same step response.    However the EW thrust signatures when the RF power was turned on were completely different.   From this observation it can be concluded the RF power is not producing thrust.   

Others have offered alternative explanations for the apparent movement when RF power is applied.   Since we are talking about only 4-5 microns of apparent movement there can be many alternative, conventional explanations.

All the essays describing these experiments (EW, Shawyer, and now Yang) make a lot of claims but show very little data.    Shawyer has been doing this since 2003 and yet his raw data has never been released.   EW has released a few graphs but one can assume that given the amount of time they have been experimenting there is a lot more data.   So have they cherry-picked the data and just shown us the graphs that appear to show thrust?   If so that would indicate a very low percentage of possibly "good" tests.

In Monday's new York Times (pages A1, A11  "Maligned study..") there is a piece on a paper that the journal Science is considering retracting.   One of the authors has his hopes set on a "dream job" as a professor at Princeton.  However his faculty  advisor has asked Science to retract the paper because the author "... had misrepresented his study methods and lacked the evidence to back up his findings."  (quoted from NYT article)  The author was asked several times to make his raw data available in case his work needed to be checked, but never did.

It is one thing to say you have a propellantless microwave thruster and that in a few years cars will be flying but if there is no data to support these claims any sane individual would have to say it has all been a hoax.

So to all you DIY'ers out there: Don't electrocute yourself or give yourself cataracts, etc., chasing a dream that will never materialize.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/28/2015 06:38 AM
I found this on another site it maybe of relevance to this topic. It's a new scientific paper.

Theory of everything? How spacetime is built by quantum entanglement

http://www.sciencedaily.com/releases/2015/05/150527112953.htm

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: ThinkerX on 05/28/2015 06:57 AM
Quote
It is one thing to say you have a propellantless microwave thruster and that in a few years cars will be flying but if there is no data to support these claims any sane individual would have to say it has all been a hoax.

So to all you DIY'ers out there: Don't electrocute yourself or give yourself cataracts, etc., chasing a dream that will never materialize.

Expressing skepticism is one thing.  Discouraging independent investigation is something else.

And I stand squarely on the fence with this device - the theories and experiments all have problems, yet there is just enough in the way of ambiguous or positive results to warrant further investigation. 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Stormbringer on 05/28/2015 07:18 AM
so, no scat, there i was... I learned you can do stuff that violates the laws of physics so long as you label the process as happening in imaginary time even if it has real physical consequences.

http://phys.org/news/2015-05-physicists-quantum-tunneling-mystery.html

Synopsis: Massive things that quantum tunnel can violate the physical speed limit of light so long as there isn't anybody watching and there cannot be anyone watching because it happens in imaginary time.

I don't know about you; but i kind of had a different idea of what "imaginary" means but evidently imaginary does NOT mean unreal.

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/28/2015 07:38 AM
This says the imbalance on just the end plates is 100X more significant than those on the sidewalls. So my thought experiment is optimizing that end of it, so to speak.  ;D


On condition of course that it is really the case, wouldn't it make sense then to use "metglas" on the (small?) endplate, because it has a dramatically increased magnetic permeability, compared to copper?(x1000000)
Wouldn't that greatly amplify that magnetic imbalance then?

http://en.wikipedia.org/wiki/Permeability_%28electromagnetism%29

It was talked about some 150 pages ago or so, but it fell between the cracks...

IF we assume that the EMdrive gets validated as a thrust generating device, I think we should try to setup some experimental parameters that will test each of the proposed theories on their validity.
Maybe we should setup a listing of the proposed theories/conjectures we got so far and how we could experimentally test them individually? if they fail, you can scrap the theory and move to the next one...
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/28/2015 07:39 AM

so, no scat, there i was... I learned you can do stuff that violates the laws of physics so long as you label the process as happening in imaginary time even if it has real physical consequences.

http://phys.org/news/2015-05-physicists-quantum-tunneling-mystery.html

Synopsis: Massive things that quantum tunnel can violate the physical speed limit of light so long as there isn't anybody watching and there cannot be anyone watching because it happens in imaginary time.

I don't know about you; but i kind of had a different idea of what "imaginary" means but evidently imaginary does NOT mean unreal.

Isn't that the same thing as I just posted above but with a different spin, if you pardon the pun?

I saw someone suggesting & no idea if it's correct that this allows theoretical for greater than speed of light & teleportation?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Stormbringer on 05/28/2015 07:46 AM

so, no scat, there i was... I learned you can do stuff that violates the laws of physics so long as you label the process as happening in imaginary time even if it has real physical consequences.

http://phys.org/news/2015-05-physicists-quantum-tunneling-mystery.html

Synopsis: Massive things that quantum tunnel can violate the physical speed limit of light so long as there isn't anybody watching and there cannot be anyone watching because it happens in imaginary time.

I don't know about you; but i kind of had a different idea of what "imaginary" means but evidently imaginary does NOT mean unreal.

Isn't that the same thing as I just posted above but with a different spin, if you pardon the pun?

I saw someone suggesting & no idea if it's correct that this allows theoretical for greater than speed of light & teleportation?

It may just be the articles treatment of the underlying paper but but i do not take it as being the same thing as your post. But really a half a year  to  a year ago there were a couple of articles on entanglement and wormholes and gravity all being related in the manner you suggest. In my case the thing was quantum tunneling of a massive object being instantaneous and thus implying FTL travel albeit in "imaginary" time. :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Paul Novy on 05/28/2015 07:49 AM
I'm just gonna leave this here...

"Macroscopic and Direct Light Propulsion of Bulk Graphene Material"
http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf (http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf)


Quote
The force generated from such a process/mechanism is much
larger than the force generated directly from the conventional light pressure, which is
much smaller than the force required to propel the samples.

Quote
The mechanism behind this novel phenomenon is believed to be an
efficient light-induced ejected electron emission process, following an Auger-like path
due to both the unique band structure of graphene and its macroscopic morphology of
this unique material.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Star One on 05/28/2015 08:40 AM


so, no scat, there i was... I learned you can do stuff that violates the laws of physics so long as you label the process as happening in imaginary time even if it has real physical consequences.

http://phys.org/news/2015-05-physicists-quantum-tunneling-mystery.html

Synopsis: Massive things that quantum tunnel can violate the physical speed limit of light so long as there isn't anybody watching and there cannot be anyone watching because it happens in imaginary time.

I don't know about you; but i kind of had a different idea of what "imaginary" means but evidently imaginary does NOT mean unreal.

Isn't that the same thing as I just posted above but with a different spin, if you pardon the pun?

I saw someone suggesting & no idea if it's correct that this allows theoretical for greater than speed of light & teleportation?

It may just be the articles treatment of the underlying paper but but i do not take it as being the same thing as your post. But really a half a year  to  a year ago there were a couple of articles on entanglement and wormholes and gravity all being related in the manner you suggest. In my case the thing was quantum tunneling of a massive object being instantaneous and thus implying FTL travel albeit in "imaginary" time. :)

No wonder Einstein hated all this stuff, the concepts often seem so off the wall & hard to get your head around, even one of the greatest scientific minds seemed to be driven to distraction by them let alone poor old laypeople.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 09:23 AM
i just looked at a critique based on the bayes outlook of emdrive and i can only say...bayes theorem is the dumbest thing i have ever heard of in my life.  i understand the math just fine.  its just so hand wavy abd full of hot air that i cant take the critism seriously at all.
Let's consider that the person doing the critique admits up front that he has not investigated the EM Drive experimental data.  He mentions Bayes theorem in a superficial hand-wavy way in one of hundreds of blog pieces he wrote (he did not calculate the Bayes probability). Don't think that Bayes theorem is a dumb thing.  Bayes theorem can and has been used successfully for countless applications.  Its renaissance and re-adoption after WWII is due to its success in solving practical problems. 

Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 09:49 AM
From which we conclude, because 0 <= Df <= 1, that
0 <= F <= 2 Q P/c , where F is the thrust.

So with Df = 1 and even if Q =1, F is twice that which would be delivered by a photon rocket at power P. Sound right to you?
This is a case of having to mind your Q's so to speak.  :)

There is no critical signifcance for the value of Q=1 that you chose, to question  that there is something inherently wrong.  Q=1 is an arbitrary, underdamped value of Q.

A casual reader may think that a photon rocket has Q=1, and therefore you have proven something significant.

That's not the case.

A photon rocket is an open chamber. Not a resonating cavity. 

Still if you want to force a comparison with a photon rocket, somehow, then you are off by a factor of 2.

(Instead of the value of Q=1 arbitrarily chosen in your example), the value of Q= ½ has important signficance: it is a critically damped quality factor. Like an overdamped system, the output does not oscillate, and does not overshoot its steady-state output (i.e., it approaches a steady-state asymptote). Like an underdamped response, the output of such a system responds quickly to a unit step input. Critical damping results in the fastest response (approach to the final value) possible without overshoot.

For Q= ½, and Df=1, Shawyer's expression gives the thrust of a photon rocket.

(http://www.jgsee.kmutt.ac.th/exell/PracMath/Instr4.gif)
(http://www.jgsee.kmutt.ac.th/exell/PracMath/Instr5.gif)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: vulture4 on 05/28/2015 10:09 AM
In the Chinese devices, the test device movement is horizontal, so external rising hot air and internal buoyancy effects of heated air should have little effect on horizontal thrust.
More than half a century ago I played with a child's toy called a Crooks radiometer, in which a small pinwheel with vanes that are black on one side and white on the other is mounted in a glass bulb under a near (but not total) vacuum. https://en.wikipedia.org/wiki/Radiometer
In sunlight the dark side of each vane becomes warmer than the light side, and imparts a higher thermal recoil to air molecules that contact it, producing a dramatically unbalanced horizontal force that spins the pinwheel. A related device called the Nichols radiometer compensates for molecular effects and measures the actual radiation pressure of incident photons on a silvered vane. https://en.wikipedia.org/wiki/Nichols_radiometer Similarly, the anomalous acceleration of the Pioneer probes as they departed from the solar system, at one time felt to indicate a "new physics" effect, was eventually concluded to be thermal recoil produced by the emission of infrared photons from the warmer parts of the spacecraft due to the asymmetric heating produced by the nuclear power source. https://en.wikipedia.org/wiki/Pioneer_anomaly  Finally, as you suggest, thermal convection can also produce forces on a heated object.

So I think it can be fairly said that horizontal or vertical forces as great or greater than those reported can easily occur due to thermal effects. Moreover, the presence of such confounding factors is the rule rather than the exception in physics. That is why theory must come first in physics. For example, the static Casimir effect was recently measured in a laboratory, but the theory underlying the effect had already been so well established that the experiment was considered simply a demonstration of what was already known, and was precisely consistent with the predictions of theory.

In the case of the frustum resonator, the principle that is proposed is that the group velocity of photons reflected from the small end of the resonator is lower than those reflected from the large end. It is conceivable to me that the group velocity of the photons in the resonator could increase as they progress along its axis towards the large end. http://www.microwaves101.com/encyclopedias/waveguide-mathematics  I think the relevant question that has not been answered is how these photons could be accelerated without exchanging momentum with some element of the surrounding medium, which would of course counterbalance the excess force imparted by their reflection from the end of the chamber. The "reactionless drive" that must be explained theoretically by the investigators is the proposed reactionless acceleration and deceleration of these photons.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/28/2015 11:16 AM
The problem is that if you talk about "accelerating" or "decelerating" photons when there is no change in refractive index in play, you will be dismissed peremptorily by physicists.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: vulture4 on 05/28/2015 11:31 AM
The problem is that if you talk about "accelerating" or "decelerating" photons when there is no change in refractive index in play, you will be dismissed peremptorily by physicists.
A waveguide is very similar to a lens in this regard, indeed one could consider the equivalent case of light resonating between two mirrors at the ends of a tube floating in space. Place a planar piece of glass in contact with one of the mirrors and the group velocity, and hence momentum, of the photons reflecting off that mirror will be reduced. Will this create an unbalanced force and subject the optical waveguide to reactionless acceleration? Probably not as there will likely be an opposite exchange of momentum between the light and the dielectric glass.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Chris Bergin on 05/28/2015 11:50 AM

Please check with NSF site administrators, as I am not familiar with the latest rules on creating new threads.  The only thread I introduced at NSF was this 3rd thread as Chris warned that he had to close the 2nd thread because it was too long. :)


Yeah, I think we have a pretty decent set up for this here and we're good as-is.

Remember, this is really on the edge (and falling off the edge) of what we cover here as a site and it was nearly aborted after thread one turned a bit wacky.

It became interesting when NASA folks and clearly very clever folk started posting updates and progress in Thread 2 - which went mini-viral and turned into that very heavily read thread. Given this site covers what people find interesting, we made the jump to run an article on it (noting other sites had already). Given we're a pretty big site per space flighty things, that was picked up by the mass media and it went properly viral.

Now there's a cost to that. 1) You lose context as mass media go for an angle and the angle was warp drive. 2) You get so many new people running into the site and waving their arms in the air saying "this is nonsense" or "OMG! Amazing" (both being the wrong end of the stick for a valuable discussion). 3) It can cause too much attention and scare some good folk away, 4) The subject becomes very busy it's a battle to keep the noise down (but we are attempting that, per the foundation of the site rules. It'll annoy some people, but it's something we've always done. It's never personal, it's housekeeping).

Thankfully the surge didn't create too many issues. We didn't get too many armwavers and we gained a few good members who are the ones who always stick around after the storm clears. So that's where we're at right now.

As such, Thread 3 should improve as a general discussion thread (it's been calming down nicely over recent days). We would like a new thread for updates, per how Thread 2 mainly was, but that'll depend on when there are new updates. I envision by the end of the year we'll be back into the Thread 2 type scenario.

We also have the Entry Level thread as a relief valve and Traveller has his poll thread for "what do you think?" posts.

So I think we're good right now.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/28/2015 12:03 PM
The 3 EMdrive threads together (not counting the side topics) have a whopping 1416992 views.... :o
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: StrongGR on 05/28/2015 12:06 PM
This was a thought occurring me a moment ago. I have just shown that inside these cavities there is a tiny gravitational effect. Per se this effect is too small account for the observed thrust, if confirmed. But, is there any change in the light propagation inside such cavities causing an asymmetry due to these small gravitational effects?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 12:19 PM
Two comments: a) nothing here is worth more than 2 or 3 digits of precision, and b) Df does serve at least the purpose of bounding the thrust from above at the limiting value given by Df = 1.

Calculating Shawyer Demonstrator Df.

Shawyer's thrust equation T = (2 * Df * Po * Q) / c gives us the ability to calc Df, knowing Q, T & Po as Df = (c * T) / (2 * Po * Q)

Demonstrator EM Drive, published data:

Q: 45,000
Po: 334W
T: 0.096N

Therefore Df = 0.95714. This suggests Shawyer's reported Df of 0.844 is correct as effective Q at measured power may not be 45,000 due to thermal detuning or the magnetron frequency not being at cavity resonance.

When calculating the small end diameter, we must know the TEm,n or TMm,n excitation mode as the cutoff wavelength can vary quite a lot, which effects guide wavelengths Lambda g1 and Lambda g2 and thus Df. As we don't the mode, we must assume the Df of 0.844 is the correct value. A bit of playing with modes and trying different small end values may reveal the mode and true small end size.

Have fun.

The value of Df = 0.95714 is so close to 1 and so much higher than the Design Factor for the Experimental (Df=0.48), that is suspect.  Let's take a closer look at the data for the Demonstrator.

Shawyer's papers show that instead of a single value of power, he run multiple cases for the Demonstrator, from 421 W to 1200 W, so what makes sense to use to figure out a Design Factor based on experiments is the full range of what he measured.  When one does that, the Design Factor ranges from a minimum of 0.284 to a maximum of 0.809.  Therefore the mean value of the Design Factor is around 0.5 which is close to what phaseshift calculates based on the photograph of the Demo.

Here is a Table of Design Factors based on experimental values (from data in  http://emdrive.echothis.com/Experimental_Results based on his papers):

using Df = (c * Force ) / (2 * Power * Q)  and c= 299705000 m/s (speed of light in air)


Description                     Power (W)     Q      Force (mN)   Df (from Exp.)   
Shawyer Experimental   850            5900      16              0.478
Shawyer Demo          421-1200   45000   102.30         0.809-0.284      
Brady a TM Mode          16.9             7320      0.0912      0.110
Brady b TM Mode         16.7             18100   0.0501        0.025
Brady c TE Mode           2.6             22000   0.05541       0.145

Notice that the Design Factor calculated from experimental values for the Experimental (0.478) is within 1% of the Design Factor (0.484)  based on the geometry of the Experimental, using for cut-off frequency the lowest possible natural frequency (much lower than what the Experimental was tested at). Therefore it would be illogical to use a different method to calculate cut-off frequency for the Design Factor in the Experimental than for the Demo.

Notice the extremely small values of the Design Factor for the NASA Eagleworks experiments.  They cannot be explained in terms of geometry or in terms of cut-off frequency.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 12:57 PM
For the Eagleworks team: do you report the net RF power entering the resonator (forward - reflected at feedpoint)?  Or total PA output?

For example in this picture ~50w is listed:

(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=814655;image)

I think that Paul March answered this question at previous NSF threads already: the RF power numbers they give are forward minus reflected equal net power flow into the test article. 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: JasonAW3 on 05/28/2015 01:05 PM
@Rodal

Apologies, but I thought that there'd already been some tests done in a vacume chamber with this device while still producing apparent thrust.  Was I mistaken on this?

If not, I would think that heated air convection would no longer be considered a potential factor in this device.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 01:25 PM
@Rodal

Apologies, but I thought that there'd already been some tests done in a vacume chamber with this device while still producing apparent thrust.  Was I mistaken on this?

If not, I would think that heated air convection would no longer be considered a potential factor in this device.
The only organization, to my knowledge, that has reported tests in vacuum is NASA Eagleworks.

Although Shawyer has been reporting tests for about 15 years and NPWU in China for several years, they have not reported tests in vacuum, to my knowledge.

Since the tests results by NASA in vacuum were lower than the test results in air, it very much looks like the hypothesis that there is a significant thermal "gas effect" component involved in the tests is very much still alive, particularly when considering the much higher power used by Shawyer and NPWU in China.

There is noting I have seen from the researchers that quantifies the size of this "gas effect" in the experiments conducted in air in the UK and China.  Moreover, none of these tests have been conducted with a mesh for the ends, which is the only way that Cullen (who Shawyer uses as his main reference) found to eliminate the gas effect when performing tests in air in his 1951 Ph.D. thesis (the first time that anyone was able to quantitatively measure radiation pressure due to microwaves).

That a significant gas effect component is present would not be surprising as it has been known since Maxwell in the 1870's that scientists trying to measure radiation pressure (at microwave and higher frequencies) have had to deal with such problems for over 100 years (these problems are collectively known as "the gas effect").
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 02:05 PM
I...
Point well taken.

It would be very useful to get strong skeptical reviews of Prof.Yang's paper ((translated) page 4 ( http://www.emdrive.com/NWPU2010translation.pdf  ) concerning her equations stating that having a gas/fluid with charged particles inside the EM Drive results in transfer of its momentum to the EM Drive metallic body. 
...

I was under the impression that Yang had built an EM drive and had done a series of experiments that showed it could produce a mN thrust.   There is no mention of any experiments or measurements in the above translated paper.   I'll have to tip my hat to whoever translated it.   A well done job.

So this is the problem I have with believing the EM-drive is not a hoax; or stated more politely a case of mistaken measurements.    In thread 2 I stated the EW thrust signatures were not consistent with the known step response of their torque pendulum.   The calibration pulse, generated by a capacitive device, always produced an underdamped response (thrust graph).   This is the response that anything that pushes on the cavity should produce.   If a moth flew at the cavity, this same step response would be seen.   This is an immutable physical observation of mechanical systems.  They all have a natural frequency and a damping coefficient.   Any perturbation will exhibit the same step response.    However the EW thrust signatures when the RF power was turned on were completely different.   From this observation it can be concluded the RF power is not producing thrust.   

Others have offered alternative explanations for the apparent movement when RF power is applied.   Since we are talking about only 4-5 microns of apparent movement there can be many alternative, conventional explanations.

All the essays describing these experiments (EW, Shawyer, and now Yang) make a lot of claims but show very little data.    Shawyer has been doing this since 2003 and yet his raw data has never been released.   EW has released a few graphs but one can assume that given the amount of time they have been experimenting there is a lot more data.   So have they cherry-picked the data and just shown us the graphs that appear to show thrust?   If so that would indicate a very low percentage of possibly "good" tests.

In Monday's new York Times (pages A1, A11  "Maligned study..") there is a piece on a paper that the journal Science is considering retracting.   One of the authors has his hopes set on a "dream job" as a professor at Princeton.  However his faculty  advisor has asked Science to retract the paper because the author "... had misrepresented his study methods and lacked the evidence to back up his findings."  (quoted from NYT article)  The author was asked several times to make his raw data available in case his work needed to be checked, but never did.

It is one thing to say you have a propellantless microwave thruster and that in a few years cars will be flying but if there is no data to support these claims any sane individual would have to say it has all been a hoax.

So to all you DIY'ers out there: Don't electrocute yourself or give yourself cataracts, etc., chasing a dream that will never materialize.
Can you please link to the message where you  "In thread 2 stated the EW thrust signatures were not consistent with the known step response of their torque pendulum. " or otherwise describe what thrust signatures are not consistent with the step response of the torque pendulum?

Are you stating that none of the Brady et al thrust signatures are consistent with the torque pendulum response?

I recall that the Autocorrelation and Power Spectral Density analysis I did of a few Brady et.al graphs were consistent with the torque pendulum (I only did a few ones, for which frobnicat gave numerical data), I also modeled the torque pendulum differential equation with Mathematica.

The main difference I remember was not one of not being underdamped, but as frobnicat pointed out, the period of the response was behaving as if the system had a different stiffness than expected.

There is an issue with the inclination of the setup, as pointed out by frobnicat. Also, there is definitely a big  issue with turning the EM Drive around by 180 degrees and getting a significant different measurement.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/28/2015 02:10 PM
Have asked Roger Shawyer to confirm the quoted Df for the Demonstrator EMDrive is 0.844:

http://emdrive.com/demonstratorengine.html
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 02:34 PM
Have asked Roger Shawyer to confirm the quoted Df for the Demonstrator EMDrive is 0.844:

http://emdrive.com/demonstratorengine.html
Can you please ask for him to check his original data documents (rather than his published papers) , and re-calculate the Design Factor based on known geometry, to make sure that there was not an unintended typo somewhere?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/28/2015 02:50 PM
Have asked Roger Shawyer to confirm the quoted Df for the Demonstrator EMDrive is 0.844:

http://emdrive.com/demonstratorengine.html
Can you please ask for him to check his original data documents (rather than his published papers) , and re-calculate the Design Factor based on known geometry, to make sure that there was not an unintended typo somewhere?

From work on my spreadsheet, that can easily adopt to various TMm,n and TEm,n modes, I believe it is possible to get an excitation mode that will deliver a high Df, small end operating just above cutoff (as Shawyer recommends), without using stupid geometry.

Did ask for the excitation mode. If he shares that, will be able to plug it into my spreadsheet and see what it says about small diameter.

The more I work with my spreadsheet, the more I get a good gut feeling about how the 3 dimensions, excitation mode and external Rf frequency interplay with each other to get an optimal mix of all 5 variables for max thrust per applied power.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/28/2015 03:08 PM
Slide 4, attached, of the attached larger presentation, dealing with why side wall thrust versus small end plate thrust is not a linear function is interesting.

Helps to explain why the small end plate should operate just above cutoff for highest Df and thrust. Different excitation modes will give different cutoff for a fixed size end plate. So selecting excitation mode is as much a part of EM Drive design to get optimal thrust as are the other 4 variables of external Rf frequency, big & small end plate diameters and end plate separation, which also indirectly involves slant angle and side wall force as a component of overall small end dynamics.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: OttO on 05/28/2015 03:11 PM
is there any change in the light propagation inside such cavities causing an asymmetry due to these small gravitational effects?

And we know there is an asymetry of internal infra red light.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 03:43 PM
...
From work on my spreadsheet, that can easily adopt to various TMm,n and TEm,n modes, I believe it is possible to get an excitation mode that will deliver a high Df, small end operating just above cutoff (as Shawyer recommends), without using stupid geometry...
This fact should be more important than what a spreadsheet may predict:

Using a DesignFactor ~ 1 results in a Shawyer-formula predicted thrust output

Force = (2 * Power * Q * Df) /c
         = (2 * Power * Q ) /c       for Df =1

for the Demonstrator at the maximum power tested of 1200 Watts and Q = 45000 and  c= 299705000 m/s (speed of light in air) gives

360 milliNewtons

that's 3.5 times the maximum thrust (102 milliNewtons) reported  for the Demonstrator, so something is amiss with the spreadsheet calculation or with the data reported by Shawyer.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: tchernik on 05/28/2015 03:51 PM
I'm just gonna leave this here...

"Macroscopic and Direct Light Propulsion of Bulk Graphene Material"
http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf (http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf)


Quote
The force generated from such a process/mechanism is much
larger than the force generated directly from the conventional light pressure, which is
much smaller than the force required to propel the samples.

Quote
The mechanism behind this novel phenomenon is believed to be an
efficient light-induced ejected electron emission process, following an Auger-like path
due to both the unique band structure of graphene and its macroscopic morphology of
this unique material.

While a very interesting discovery and potential  development all in itself, this graphene sponge sail would provide thrust in fully explainable ways.

By accelerating and ejecting electrons due to the material physical properties and thus, getting a reaction, it would still be a conventional rocket engine. The graphene sponge lightsail will eventually need to replenish its electrons in order to continue providing thrust.

The advantage of this is that electrons are aplenty in the vicinity of the Sun, thanks to the solar wind. Therefore I imagine an electrodynamic tether could be used to replenish the electrons on a sail like this, allowing it to continue working almost anywhere in the Solar System.

Not sure if the same would apply for trans-neptunian space or interstellar missions, though.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/28/2015 03:58 PM
...
From work on my spreadsheet, that can easily adopt to various TMm,n and TEm,n modes, I believe it is possible to get an excitation mode that will deliver a high Df, small end operating just above cutoff (as Shawyer recommends), without using stupid geometry...
As you said that you care much more about experimental reports of thrust forces than about what a theory may predict, then this fact should be more important than what a spreadsheet may predict:

Using a DesignFactor ~ 1 results in a Shawyer-formula predicted thrust output

Force = (2 * Power * Q * Df) /c
         = (2 * Power * Q ) /c       for Df =1

for the Demonstrator at the maximum power tested of 1200 Watts and Q = 45000 and  c= 299705000 m/s (speed of light in air) gives

360 milliNewtons

that's 3.5 times the maximum thrust (102 milliNewtons) reported  for the Demonstrator, so something is amiss with your spreadsheet calculation or with the data reported by Shawyer.

Apologies if you misunderstood me.

Theory of HOW it works is fine as that helps to predicts device operational parameters.

Theory of WHY it works, well that is not involved in building hardware.

Shawyer didn't report thrust at 1.2kWs. The only reported thrust was 96mN at 334W. Also reported was the maximum specific thrust of 214mN/kW over 134 test runs.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 04:05 PM
I changed the wording  :)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: txdrive on 05/28/2015 04:11 PM
@Rodal

Apologies, but I thought that there'd already been some tests done in a vacume chamber with this device while still producing apparent thrust.  Was I mistaken on this?

If not, I would think that heated air convection would no longer be considered a potential factor in this device.
The only organization, to my knowledge, that has reported tests in vacuum is NASA Eagleworks.

Although Shawyer has been reporting tests for about 15 years and NPWU in China for several years, they have not reported tests in vacuum, to my knowledge.

Since the tests results by NASA in vacuum were lower than the test results in air, it very much looks like the hypothesis that there is a significant thermal "gas effect" component involved in the tests is very much still alive, particularly when considering the much higher power used by Shawyer and NPWU in China.

There is noting I have seen from the researchers that quantifies the size of this "gas effect" in the experiments conducted in air in the UK and China.  Moreover, none of these tests have been conducted with a mesh for the ends, which is the only way that Cullen (who Shawyer uses as his main reference) found to eliminate the gas effect when performing tests in air in his 1951 Ph.D. thesis (the first time that anyone was able to quantitatively measure radiation pressure due to microwaves).

That a significant gas effect component is present would not be surprising as it has been known since Maxwell in the 1870's that scientists trying to measure radiation pressure (at microwave and higher frequencies) have had to deal with such problems for over 100 years (these problems are collectively known as "the gas effect").
Rather than using vacuum or a mesh, it'd be preferable if they enclosed everything in an air-tight box that was suspended to make it insensitive to changes in centre of mass.

Keep in mind also that (with Shawyer's formula) the net thrust may be stronger than a photon rocket but it is no stronger than a mirror (and with mirrors it is well known that effects due to heating are very huge comparing to pressure, unless very special conditions apply).

Regarding the EagleWorks results (let's not tarnish NASA's reputation as a whole, please, with what most certainly will turn out to be a dud), their thrust is much less than predicted by Shawyer's formula, thus constituting a falsification.

Shawyer's mistaken calculations of radiation pressure are not just theoretically wrong, they have been experimentally falsified by EagleWorks.

Eagleworks also obtained no thrust without plastic inside the cavity, or when the plastic was not firmly in contact with the cavity wall, which would decrease heat conduction into the plastic but not affect EM fields otherwise. edit: I do not have the reference right now but I believe March had posted that when a plastic screw melted, the drive performance decreased.

Now with regards to EagleWorks and their far smaller forces which don't replicate when turned around by 180 degrees: Their interpretation that it is a sum of some classical forces they don't understand with some anomalous novel physics they are discovering... well it leaves much to be desired. If they were quantifying their errors better they'd simply have something like 50uN ±100uN : a falsification of Shawyer's theory, and a multitude of classical forces that are known to arise at such power levels limiting the precision of said falsification. It took very smart people a long time to fully understand Crookes radiometer.

edit: Throw in a couple tensioned leaf springs, heated by electrical current, some plastic the edges of which may be decomposing (strong electric field at a discontinuity in dielectric constant), plastic screws literally melting. Put it onto a non-vertical pendulum that is sensitive to shifts in centre of mass. Non-null findings of some kind (due to classical physics)  are then guaranteed, and they're guaranteed to be very difficult to understand.

edit: CoM -> centre of mass, due to use of CoM to mean "conservation of momentum".
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/28/2015 04:43 PM
Flight Thruster build update:

From the best photo of the Flight Thruster I could find and allowing for 2mm thick walls, to add thermal mass and reduce the rate of thermal expansion, the following internal Flight Thruster dimensions were obtained:

Length:   138.6mm
Small diameter:   125.7mm
Big diameter:   231.4mm

Applying those to my spreadsheet generated:

Df:   0.638
Frequency:   3.85GHz
Mode:   TE013

I then asked Roger Shawyer did I get close? His reply:

Df:  0.635
Frequency:   3.9003GHz
Mode:   TE013

I'm VERY happy with that as my Rf gen can easily go to that frequency. Time now to finalise drawings and get some copper sheet laser cut.

Roger also mentioned it is best to give the internal frustum surfaces a nice bright shinny polish. No need for Silver or Gold overcoats.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: MyronQG on 05/28/2015 05:10 PM
@Rodal

Apologies, but I thought that there'd already been some tests done in a vacume chamber with this device while still producing apparent thrust.  Was I mistaken on this?

If not, I would think that heated air convection would no longer be considered a potential factor in this device.
The only organization, to my knowledge, that has reported tests in vacuum is NASA Eagleworks.

Although Shawyer has been reporting tests for about 15 years and NPWU in China for several years, they have not reported tests in vacuum, to my knowledge.

Since the tests results by NASA in vacuum were lower than the test results in air, it very much looks like the hypothesis that there is a significant thermal "gas effect" component involved in the tests is very much still alive, particularly when considering the much higher power used by Shawyer and NPWU in China.

There is noting I have seen from the researchers that quantifies the size of this "gas effect" in the experiments conducted in air in the UK and China.  Moreover, none of these tests have been conducted with a mesh for the ends, which is the only way that Cullen (who Shawyer uses as his main reference) found to eliminate the gas effect when performing tests in air in his 1951 Ph.D. thesis (the first time that anyone was able to quantitatively measure radiation pressure due to microwaves).

That a significant gas effect component is present would not be surprising as it has been known since Maxwell in the 1870's that scientists trying to measure radiation pressure (at microwave and higher frequencies) have had to deal with such problems for over 100 years (these problems are collectively known as "the gas effect").
Rather than using vacuum or a mesh, it'd be preferable if they enclosed everything in an air-tight box that was suspended to make it insensitive to changes in centre of mass.

Keep in mind also that (with Shawyer's formula) the net thrust may be stronger than a photon rocket but it is no stronger than a mirror (and with mirrors it is well known that effects due to heating are very huge comparing to pressure, unless very special conditions apply).

Regarding the EagleWorks results (let's not tarnish NASA's reputation as a whole, please, with what most certainly will turn out to be a dud), their thrust is much less than predicted by Shawyer's formula, thus constituting a falsification.

Shawyer's mistaken calculations of radiation pressure are not just theoretically wrong, they have been experimentally falsified by EagleWorks.

Eagleworks also obtained no thrust without plastic inside the cavity, or when the plastic was not firmly in contact with the cavity wall, which would decrease heat conduction into the plastic but not affect EM fields otherwise.

Now with regards to EagleWorks and their far smaller forces which don't replicate when turned around by 180 degrees: Their interpretation that it is a sum of some classical forces they don't understand with some anomalous novel physics they are discovering... well it leaves much to be desired. If they were quantifying their errors better they'd simply have something like 50uN ±100uN : a falsification of Shawyer's theory, and a multitude of classical forces that are known to arise at such power levels limiting the precision of said falsification. It took very smart people a long time to fully understand Crookes radiometer.

edit: Throw in a couple tensioned leaf springs, heated by electrical current, some plastic the edges of which may be decomposing (strong electric field at a discontinuity in dielectric constant), plastic screws literally melting. Put it onto a non-vertical pendulum that is sensitive to shifts in CoM. Non-null findings of some kind are then guaranteed, and they're guaranteed to be very difficult to understand.

I fully agrre with this viewpoint. Bottom line is: the EMdrive cannot work according to the presently accepted theoretical framework in propulsion science, unless a strong deviation from nearly flat spacetime is induced in its surroundings, which could easily be detected by sensitive enough accelerometers. If you want to half-convince people that it really works (before going to full-fledged orbit control demonstration), just put the whole device (test article + power supply + wirings + etc.) onto the thrust sensing rig, in a so to speak "closed system" configuration, and operate it under high vacuum conditions. It is also advisable to always measure thrust by optical means to minimize EMI on the measurement electronics, to run tests using "dummy" equivalent electrical loads with the same input power and to run tests with the reaL thing but with the sensing rig "tight-locked" to quantify readings coming from mundane causes.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/28/2015 05:19 PM
I'm just gonna leave this here...

"Macroscopic and Direct Light Propulsion of Bulk Graphene Material"
http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf (http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf)


Quote
The force generated from such a process/mechanism is much
larger than the force generated directly from the conventional light pressure, which is
much smaller than the force required to propel the samples.


Quote
The mechanism behind this novel phenomenon is believed to be an
efficient light-induced ejected electron emission process, following an Auger-like path
due to both the unique band structure of graphene and its macroscopic morphology of
this unique material.


Wow! Forces orders of magnitude greater than photon pressure of the illuminating laser - due to electron emmission.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: RERT on 05/28/2015 05:26 PM
Err...I don't know if this is a lightbulb moment or a senior moment, but if the cavity generates an asymmetrical pattern of eddy currents in the surface of the frustrum, wouldn't that interact with the Earth's magnetic field to produce a net force?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/28/2015 05:33 PM
Flight Thruster build update:

From the best photo of the Flight Thruster I could find and allowing for 2mm thick walls, to add thermal mass and reduce the rate of thermal expansion, the following internal Flight Thruster dimensions were obtained:

Length:   138.6mm
Small diameter:   125.7mm
Big diameter:   231.4mm

Applying those to my spreadsheet generated:

Df:   0.638
Frequency:   3.85GHz
Mode:   TE013

I then asked Roger Shawyer did I get close? His reply:

Df:  0.635
Frequency:   3.9003GHz
Mode:   TE013

I'm VERY happy with that as my Rf gen can easily go to that frequency. Time now to finalise drawings and get some copper sheet laser cut.

Roger also mentioned it is best to give the internal frustum surfaces a nice bright shinny polish. No need for Silver or Gold overcoats.

Using the following dimensions:

Length:   138.6mm
Small diameter:   125.7mm
Big diameter:   231.4mm

and using the speed of light in air:

cAir = 299705000 (meter/s)

My exact solution gives:

Mode:   TE013
Frequency:   3.94571 GHz

The results data I received from Roger was from the SPR inhouse EM Drive design & development software suite.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: MyronQG on 05/28/2015 05:35 PM
I'm just gonna leave this here...

"Macroscopic and Direct Light Propulsion of Bulk Graphene Material"
http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf (http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf)


Quote
The force generated from such a process/mechanism is much
larger than the force generated directly from the conventional light pressure, which is
much smaller than the force required to propel the samples.


Quote
The mechanism behind this novel phenomenon is believed to be an
efficient light-induced ejected electron emission process, following an Auger-like path
due to both the unique band structure of graphene and its macroscopic morphology of
this unique material.


Wow! Forces orders of magnitude greater than photon pressure of the illuminating laser - due to electron emmission.

What about the growing positive charge that develops on the thruster? It seems there will be necessary to inject protons into the electron jet to maintain neutrality of charge.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: sfrank on 05/28/2015 05:50 PM
This says the imbalance on just the end plates is 100X more significant than those on the sidewalls. So my thought experiment is optimizing that end of it, so to speak.  ;D


...

Maybe we should setup a listing of the proposed theories/conjectures we got so far and how we could experimentally test them individually? if they fail, you can scrap the theory and move to the next one...

I accept the challenge!  http://emdrive.echothis.com/List_of_Suggested_Experiments
I'm going to work backwards through the threads.  It will take me awhile to get everything listed.  If you have a particular idea you'd like listed, just pm it to me and I'll add it immediately.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/28/2015 05:53 PM
Flight Thruster build update:

From the best photo of the Flight Thruster I could find and allowing for 2mm thick walls, to add thermal mass and reduce the rate of thermal expansion, the following internal Flight Thruster dimensions were obtained:

Length:   138.6mm
Small diameter:   125.7mm
Big diameter:   231.4mm

Applying those to my spreadsheet generated:

Df:   0.638
Frequency:   3.85GHz
Mode:   TE013

I then asked Roger Shawyer did I get close? His reply:

Df:  0.635
Frequency:   3.9003GHz
Mode:   TE013

I'm VERY happy with that as my Rf gen can easily go to that frequency. Time now to finalise drawings and get some copper sheet laser cut.

Roger also mentioned it is best to give the internal frustum surfaces a nice bright shinny polish. No need for Silver or Gold overcoats.

Using the following dimensions:

Length:   138.6mm
Small diameter:   125.7mm
Big diameter:   231.4mm

and using the speed of light in air:

cAir = 299705000 (meter/s)

My exact solution gives:

Mode:   TE013
Frequency:   3.94571 GHz

The results data I received from Roger was from the SPR inhouse EM Drive design & development software suite.

WARNING

It looks like you are aiming for a degenerate natural frequency  as this Transverse Magnetic mode has the same natural frequency:

TM113

as TE013

Using coax to feed in the Rf, you need very different antenna and physical antenna placement points to excite either TM or TE mode.

So not an issue.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/28/2015 06:07 PM
I'm just gonna leave this here...

"Macroscopic and Direct Light Propulsion of Bulk Graphene Material"
http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf (http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf)


Quote
The force generated from such a process/mechanism is much
larger than the force generated directly from the conventional light pressure, which is
much smaller than the force required to propel the samples.


Quote
The mechanism behind this novel phenomenon is believed to be an
efficient light-induced ejected electron emission process, following an Auger-like path
due to both the unique band structure of graphene and its macroscopic morphology of
this unique material.


Wow! Forces orders of magnitude greater than photon pressure of the illuminating laser - due to electron emmission.

What about the growing positive charge that develops on the thruster? It seems there will be necessary to inject protons into the electron jet to maintain neutrality of charge.

Yes, that's always a problem with ion engines, and this electron engine would have a similar problem. But it could be that illuminating this device with onboard diode lasers could act to neuralize the charge buildup on an ion engine at a much lower mass penalty. This material was like 10 kg/m3 if my conversion was correct, and a cubic meter seems way more than would be needed.

I'm not familiar with the neutralizing techniques used on ion engines or the mass of the neutralizing system but almost any conventional hardware is going to necessarily be more massive. The down side is that a system using this graphene foam might be physically large which, due to structure, would negate any mass advantage of the material.

But enough of that, I don't see how this relates to the EM drive ... but it is a very interesting phenomon by itself and the paper is very readable giving detailed experimental results. I wish we could get the same detailed experimental results from the EM drive work.

Maybe from The Traveller - Mulletron - SeeShell (if she bulids one) - or one of several others to numerous to mention.  Do we have a list anywhere of all of the DIY efforts ongoing or planned?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: sfrank on 05/28/2015 06:26 PM
...

Maybe from The Traveller - Mulletron - SeeShell (if she bulids one) - or one of several others to numerous to mention.  Do we have a list anywhere of all of the DIY efforts ongoing or planned?

http://emdrive.echothis.com/Building

9 listed so far!  Once they really get going we can make individual wiki pages for tracking each person's tests. I have a feeling at some point in the next few months we'll be innundated with experimental results.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/28/2015 06:27 PM

Maybe from The Traveller - Mulletron - SeeShell (if she bulids one) - or one of several others to numerous to mention.  Do we have a list anywhere of all of the DIY efforts ongoing or planned?
I am working on building one. I have an idea that I'm still working on that's a little bit different than anything else.  I'm still working out details of the build and design. At my age I can't afford redos or mistakes so I'm slowly working through the details. Not quite ready to release it for peer consumption. Thanks for remembering me, it means someone is listening to my babbling. ;)
Shell 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: rfmwguy on 05/28/2015 06:28 PM
I'm just gonna leave this here...

"Macroscopic and Direct Light Propulsion of Bulk Graphene Material"
http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf (http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf)


Quote
The force generated from such a process/mechanism is much
larger than the force generated directly from the conventional light pressure, which is
much smaller than the force required to propel the samples.

Quote
The mechanism behind this novel phenomenon is believed to be an
efficient light-induced ejected electron emission process, following an Auger-like path
due to both the unique band structure of graphene and its macroscopic morphology of
this unique material.

Funny you mentioned graphene material...in thread #2 I posted a carbon black (graphene derivative) HDPE dielectric study...regardless, there seems to be something interesting going on...secret sauce?  ;)

"Here's an old Bulgarian Science Foundation paper where an HDPE was studied using MW (2-10 GHz) : ftp://213.176.96.142/sciencedirect48477b28-4072-20141124031119.pdf

Seems they are quite interested in absorption and reflection performance with the introduction of acetylene carbon black (CB) into HDPE. Doncha love mixing  chemistry and electronics?  :D

"It is obvious that the CB concentration influence on the microwave properties is the strongest in the frequency range 2–3 GHz. At optimum CB concentration (17.5 mass%), the coefficient of attenuation reaches 5 dB/mm,
while the coefficient of reflection is close to the starting HDPE coefficient, i.e., the absorption
activity is more than 10 times greater than the reflection activity.""
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: JasonAW3 on 05/28/2015 06:38 PM
@Rodal

Apologies, but I thought that there'd already been some tests done in a vacume chamber with this device while still producing apparent thrust.  Was I mistaken on this?

If not, I would think that heated air convection would no longer be considered a potential factor in this device.
The only organization, to my knowledge, that has reported tests in vacuum is NASA Eagleworks.

Although Shawyer has been reporting tests for about 15 years and NPWU in China for several years, they have not reported tests in vacuum, to my knowledge.

Since the tests results by NASA in vacuum were lower than the test results in air, it very much looks like the hypothesis that there is a significant thermal "gas effect" component involved in the tests is very much still alive, particularly when considering the much higher power used by Shawyer and NPWU in China.

There is noting I have seen from the researchers that quantifies the size of this "gas effect" in the experiments conducted in air in the UK and China.  Moreover, none of these tests have been conducted with a mesh for the ends, which is the only way that Cullen (who Shawyer uses as his main reference) found to eliminate the gas effect when performing tests in air in his 1951 Ph.D. thesis (the first time that anyone was able to quantitatively measure radiation pressure due to microwaves).

That a significant gas effect component is present would not be surprising as it has been known since Maxwell in the 1870's that scientists trying to measure radiation pressure (at microwave and higher frequencies) have had to deal with such problems for over 100 years (these problems are collectively known as "the gas effect").

However, there did appear to be thrust effects in the vacume, although much reduced compared to those in atmosphere?

I really wish we had a page we could go to to compare the results of each test in a comparitive fashion.  Dredging through hundreeds of Emails to try to fimnd answers that have already been given, in one form or another, is a real pain.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/28/2015 06:58 PM
I accept the challenge!  http://emdrive.echothis.com/List_of_Suggested_Experiments
I'm going to work backwards through the threads.  It will take me awhile to get everything listed.  If you have a particular idea you'd like listed, just pm it to me and I'll add it immediately.

Maybe add R.Shawyer also, as he has build a nitrogen cooled 2nd generation EMdrive, with the intention to increase Q.
His test, if successful, would prove that a higher Q does indeed result in more thrust and consequently send all theories based on attenuation of waves to the bin...

HOPEFULLY, he's prepared to share some more technical/data details... :-\
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/28/2015 07:00 PM
This says the imbalance on just the end plates is 100X more significant than those on the sidewalls. So my thought experiment is optimizing that end of it, so to speak.  ;D


On condition of course that it is really the case, wouldn't it make sense then to use "metglas" on the (small?) endplate, because it has a dramatically increased magnetic permeability, compared to copper?(x1000000)
Wouldn't that greatly amplify that magnetic imbalance then?

http://en.wikipedia.org/wiki/Permeability_%28electromagnetism%29

It was talked about some 150 pages ago or so, but it fell between the cracks...

IF we assume that the EMdrive gets validated as a thrust generating device, I think we should try to setup some experimental parameters that will test each of the proposed theories on their validity.
Maybe we should setup a listing of the proposed theories/conjectures we got so far and how we could experimentally test them individually? if they fail, you can scrap the theory and move to the next one...

I would tend to agree, Metglass at the Large end, would increase the thrust. Whether or not it would increase it as much as De Aquino thinks it will, is debatable.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: kml on 05/28/2015 07:10 PM
Using the following dimensions:

Length:   138.6mm
Small diameter:   125.7mm
Big diameter:   231.4mm

and using the speed of light in air:

cAir = 299705000 (meter/s)

My exact solution gives:

Mode:   TE013
Frequency:   3.94571 GHz

Mode:   TE012
Frequency:   3.10927 GHz

Mode:   TE011
Frequency:   2.37833 GHz

So the question is: why are you going to excite this with TE013 at 3.95GHz, when you could be exiting it a 2.38 GHz (a frequency much closer to the usual magnetron frequency) in mode TE011 which should give you a greater amplitude (*) ?

Does your spreadsheet predict that you are going to get a higher thrust force with TE013 than with TE011 ?

Both modes TE011 and TE013 have identical electromagnetic field variation in the circular cross-section, the only difference is that TE013 has a higher frequency variation in the longitudinal direction.


(*) 1) Amplitude of mode shapes decreases with frequency, in general, for all kinds of vibrations and 2) Look at Notsosureofit's thrust force formula

Would TE011 actually work? 2.37GHz is below the TE01 cutoff frequency of 2.9GHz for a cylindrical waveguide of the small end dimension (125mm).     
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/28/2015 07:37 PM
Hot Tub Time, brain is fried! No, it's not a Time Machine Hot Tub as some have suggested. ;)

For the last several weeks I've been working, reading and even watching very good educational youtube videos to catch up because so many things just were not making sense. True, a 40 year old education is a little Model-T as far as current science is concerned and when I started this I assumed most of the foundations that were laid down during school would stand the test of time. Well, I learned some things change and some things never do.

I just read a very good paper and it exemplifies what I've been seeing and why it's a good thing I'm taking the time to re-learn and accept some "new" knowledge. Not as easy when I was much younger but,  I've learned a few things since then.

Build a EM Thruster? You betcha. Be safe? ? No question. Know how and why it works? Yep! That's the key. I've never built anything in my life without knowing the how and whys, it's the way I am.

Thanks for all the wonderful minds here, I'm learning so much and hopefully I can return the favor.

Oh, here is the link to this paper that has put many things into perspective for me and I think it's a good read.
Shell
http://arxiv.org/pdf/gr-qc/0205066.pdf
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/28/2015 07:38 PM
I'm just gonna leave this here...

"Macroscopic and Direct Light Propulsion of Bulk Graphene Material"
http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf (http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf)


Quote
The force generated from such a process/mechanism is much
larger than the force generated directly from the conventional light pressure, which is
much smaller than the force required to propel the samples.

Quote
The mechanism behind this novel phenomenon is believed to be an
efficient light-induced ejected electron emission process, following an Auger-like path
due to both the unique band structure of graphene and its macroscopic morphology of
this unique material.

This article is showing that for certain types of materials, light can impart more force to the material, than it would if it were simply used to as a photon rocket to push the same material. The difference is the Auger Effect, where the incoming light causes a population inversion in the material, that then causes electrons to be ejected from the material, greatly increasing the force by many orders of magnitude. Perhaps a similar effect can be obtained asymmetrically in a cavity?

Thank you for posting it!

Todd
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/28/2015 07:42 PM
Quote
The only advantage I see with TE013 is that it has the Poynting vector concentrated at the small end, and a local high amplitude at the small end.

Speaking of the Poynting vector, some number of pages back, you (Dr. Rodal) calculated that it has a zero average over a full wavelength in the cavity. Is that a full wavelength of the drive frequency, or a full wavelength of the stress tensor?

The reason I ask is because when using a mode TX m,n,p, if p is odd then the cavity doesn't have a full wavelength of the drive frequency.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Mulletron on 05/28/2015 08:05 PM
...Would TE011 actually work? 2.37GHz is below the TE01 cutoff frequency of 2.9GHz for a cylindrical waveguide of the small end (125cm).   
TE011 is actually not cut-off according to the exact solution with spherical ends for those dimensions listed above (125.7mm).   It looks good and strong, very clear signal in the exact solution.

It would have higher attenuation at the small end, which according to Todd's theory -which has my seal of approval  :) - is a plus.

I suppose that those that think that attenuation is bad may opt against, but it would be nice to test.

The only advantage I see with TE013 is that it has the Poynting vector concentrated at the small end, and a local high amplitude at the small end.

Hey Todd (WarpTech), we need to get your theory written up and in the Wiki http://emdrive.echothis.com/Theory
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Flyby on 05/28/2015 08:10 PM
Ayeye skipper.....Raises hand for the "Todd Conjecture"...  :P
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: rfmwguy on 05/28/2015 08:19 PM
(...)
Oh, here is the link to this paper that has put many things into perspective for me and I think it's a good read.
Shell
http://arxiv.org/pdf/gr-qc/0205066.pdf
Great article, struggled abit, but demonstrates the uncertainties between classic and "modern" physics. The CoE/CoM handwavers must sense something is afoot. Pretty sure the resonance/shape frustum cavity is partlally responsible for the apparent "effect" and cranking more power may increase it; but it may reach a point of diminishing returns or thermal/practical limits due to materials knowledge or science. The dielectric material has been of special interest (obsession)  ;) to me. Can the "effect" be amplified exponentially, not by an increase in power, but by materials in the small end of the cavity. Guess I'm a fan of lower power experimentation with dielectric material as the only variable from test to test. Might have to break out my soldering iron after all... ;D
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/28/2015 08:30 PM
(...)
Oh, here is the link to this paper that has put many things into perspective for me and I think it's a good read.
Shell
http://arxiv.org/pdf/gr-qc/0205066.pdf
Great article, struggled abit, but demonstrates the uncertainties between classic and "modern" physics. The CoE/CoM handwavers must sense something is afoot. Pretty sure the resonance/shape frustum cavity is partlally responsible for the apparent "effect" and cranking more power may increase it; but it may reach a point of diminishing returns or thermal/practical limits due to materials knowledge or science. The dielectric material has been of special interest (obsession)  ;) to me. Can the "effect" be amplified exponentially, not by an increase in power, but by materials in the small end of the cavity. Guess I'm a fan of lower power experimentation with dielectric material as the only variable from test to test. Might have to break out my soldering iron after all... ;D
I know, so many want high power and to push it, but you know sometimes you can't hear the band if you bang the drums to hard?
I'll tell you this, I also see the "effect" under an influence with another material in the small end, just too many things that are clicking right about it. 
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: rfmwguy on 05/28/2015 08:39 PM
(...)
Oh, here is the link to this paper that has put many things into perspective for me and I think it's a good read.
Shell
http://arxiv.org/pdf/gr-qc/0205066.pdf
Great article, struggled abit, but demonstrates the uncertainties between classic and "modern" physics. The CoE/CoM handwavers must sense something is afoot. Pretty sure the resonance/shape frustum cavity is partlally responsible for the apparent "effect" and cranking more power may increase it; but it may reach a point of diminishing returns or thermal/practical limits due to materials knowledge or science. The dielectric material has been of special interest (obsession)  ;) to me. Can the "effect" be amplified exponentially, not by an increase in power, but by materials in the small end of the cavity. Guess I'm a fan of lower power experimentation with dielectric material as the only variable from test to test. Might have to break out my soldering iron after all... ;D
I know, so many want high power and to push it, but you know sometimes you can't hear the band if you bang the drums to hard?
I'll tell you this, I also see the "effect" under an influence with another material in the small end, just too many things that are clicking right about it.

Yes, Shell, I'd start with cavity optimization, then dielectric, then power. Dielectric variables can be "tuned" as shown in Shawyer's model and Iulian is replicating. These threads seem to be focused on cavity discussions/optimization which is needed, but phase 2 could be dielectrics...guess i'm jumping ahead too soon  8)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: tchernik on 05/28/2015 08:51 PM
(...)
Oh, here is the link to this paper that has put many things into perspective for me and I think it's a good read.
Shell
http://arxiv.org/pdf/gr-qc/0205066.pdf
Great article, struggled abit, but demonstrates the uncertainties between classic and "modern" physics. The CoE/CoM handwavers must sense something is afoot. Pretty sure the resonance/shape frustum cavity is partlally responsible for the apparent "effect" and cranking more power may increase it; but it may reach a point of diminishing returns or thermal/practical limits due to materials knowledge or science. The dielectric material has been of special interest (obsession)  ;) to me. Can the "effect" be amplified exponentially, not by an increase in power, but by materials in the small end of the cavity. Guess I'm a fan of lower power experimentation with dielectric material as the only variable from test to test. Might have to break out my soldering iron after all... ;D
I know, so many want high power and to push it, but you know sometimes you can't hear the band if you bang the drums to hard?
I'll tell you this, I also see the "effect" under an influence with another material in the small end, just too many things that are clicking right about it.

Yes, Shell, I'd start with cavity optimization, then dielectric, then power. Dielectric variables can be "tuned" as shown in Shawyer's model and Iulian is replicating. These threads seem to be focused on cavity discussions/optimization which is needed, but phase 2 could be dielectrics...guess i'm jumping ahead too soon  8)

Personally, I'm also intrigued and wondering if the presence of gas molecules in the cavity has any impact on the thrust.

It seems it does, as per NASA Eagleworks' results, but they tested a vented cavity in air and in vacuum, not with a sealed vacuum inside the cavity working with air outside, or with sealed gas in the cavit with vacuum outside.  It rests to be seen in a sealed cavity filled with air molecules or other gas still keeps the same thrust when working in a vacuum.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: SeeShells on 05/28/2015 08:55 PM
(...)
Oh, here is the link to this paper that has put many things into perspective for me and I think it's a good read.
Shell
http://arxiv.org/pdf/gr-qc/0205066.pdf
Yes, Shell, I'd start with cavity optimization, then dielectric, then power. Dielectric variables can be "tuned" as shown in Shawyer's model and Iulian is replicating. These threads seem to be focused on cavity discussions/optimization which is needed, but phase 2 could be dielectrics...guess i'm jumping ahead too soon  8)
No you're right, you never design the cart before you get the horse. In the design you need to make room for a baseline design and that includes variable input frequencies, multiple injection points, phase shifting, a cavity that's tunable, easy disassembly and assembly, different materials and test equipment and the list goes on and on.  I've had engineers working for me that wanted to build a running Cadillac when all we needed was a wheel to get rolling and we could add another one if needed. ;)
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: rthrfrd on 05/28/2015 08:57 PM
Sorry if this has been suggested already:

I would love to see a rig with all required ancillaries mounted on a rotating shaft or turntable, a rigid arm extending perpendicular to the axis of rotation, with the drive attached to the end of the arm. Accelerate the entire apparatus to a set speed and measure its rate of deceleration. The advantages for me would be:

 - Prevents any movement in the ancillaries from affecting the measurement.
 - Allows larger ancillaries (more power).
 - Control test and active test both have the apparatus in motion (no stiction).
 - Measures the cumulative effect of the device instead of just its peak - may be easier for those with less precise tools.
 - No physical connection required between sensors and apparatus.
 - No changes required to test in either direction.

Then again, perhaps such a setup isn't yet feasible with the forces involved.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Space Ghost 1962 on 05/28/2015 09:01 PM
I'm just gonna leave this here...

"Macroscopic and Direct Light Propulsion of Bulk Graphene Material"
http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf (http://arxiv.org/ftp/arxiv/papers/1505/1505.04254.pdf)


Quote
The force generated from such a process/mechanism is much
larger than the force generated directly from the conventional light pressure, which is
much smaller than the force required to propel the samples.

Quote
The mechanism behind this novel phenomenon is believed to be an
efficient light-induced ejected electron emission process, following an Auger-like path
due to both the unique band structure of graphene and its macroscopic morphology of
this unique material.

This article is showing that for certain types of materials, light can impart more force to the material, than it would if it were simply used to as a photon rocket to push the same material. The difference is the Auger Effect, where the incoming light causes a population inversion in the material, that then causes electrons to be ejected from the material, greatly increasing the force by many orders of magnitude. Perhaps a similar effect can be obtained asymmetrically in a cavity?

Thank you for posting it!

Todd
Indeed. Have been reading the threads and following the readings/theories.

Asymmetrical/antisymmetrical reflection/refraction (also anisotropic materials) have been occasionally been investigated. These often break down quickly, as they are a form of "frozen enthalpy/entropy" that get disordered/ordered. Sometimes found in semiconductors and exotic coatings. These tend to "wear out".

I *have wondered* if the decay of "thrust" might be explained by an Auger-like phenomena with such a substance that "self exhaust" over a time interval, then after a interval "reorganize" and can be "discharged again". And ... erode?

Can anyone help me to "falsify" this? As well as other "hidden propellent" mechanisms ... I wonder if coatings, "air", or dielectrics ... might be breaking down as "erosion"? Would not take much under highly accelerated group velocities to amplify thrust ...

Thank you for an enjoyable thread.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/28/2015 09:15 PM
Quote
EDIT: Oh, by the way, the Poynting vector frequency is always twice the frequency of the electromagnetic field, its period is 1/2  the period of the electromagnetic field. It reverses direction twice as often as the electromagnetic fields.
So the Poynting vector is an even number of cycles no matter the number of half-cycles of the drive frequency. Well, next we ask, is the drive frequency (period, wavelength) always an interger number of half-cycles?

Seems it must be in order to resonate but the shape of the cavity and the existance of the dielectric makes one wonder, what is the effective drive frequency as far as the Poynting vector is concerned and does it remain always an even number of cycles everywhere within the cavity?

Perhaps a more salient question would be, what is the strength of the Poynting vector force over one-half cycle as that should be the maximum Poynting force attainable, and how does it compare to F = 2PQ/c?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/28/2015 09:32 PM
Quote
EDIT: Oh, by the way, the Poynting vector frequency is always twice the frequency of the electromagnetic field, its period is 1/2  the period of the electromagnetic field. It reverses direction twice as often as the electromagnetic fields.
So the Poynting vector is an even number of cycles no matter the number of half-cycles of the drive frequency. Well, next we ask, is the drive frequency (period, wavelength) always an interger number of half-cycles?

Seems it must be in order to resonate but the shape of the cavity and the existance of the dielectric makes one wonder, what is the effective drive frequency as far as the Poynting vector is concerned and does it remain always an even number of cycles everywhere within the cavity?

Perhaps a more salient question would be, what is the strength of the Poynting vector force over one-half cycle as that should be the maximum Poynting force attainable, and how does it compare to F = 2PQ/c?

Only the Experimental EM Drive used an internal small end dielectric. As a result, it had low Q and low thrust.

The Demonstrator and Flight Thruster EM Drives are high Q and high thrust devices which did not use a dielectric.

Shawyer says using a dielecrtic:

1) increases loss,

2) reduces Q,

3) reduces thrust.

His reported results back up that claim

So why the interest in dielectrics?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: aero on 05/28/2015 09:50 PM
Quote
EDIT: Oh, by the way, the Poynting vector frequency is always twice the frequency of the electromagnetic field, its period is 1/2  the period of the electromagnetic field. It reverses direction twice as often as the electromagnetic fields.
So the Poynting vector is an even number of cycles no matter the number of half-cycles of the drive frequency. Well, next we ask, is the drive frequency (period, wavelength) always an interger number of half-cycles?

Seems it must be in order to resonate but the shape of the cavity and the existance of the dielectric makes one wonder, what is the effective drive frequency as far as the Poynting vector is concerned and does it remain always an even number of cycles everywhere within the cavity?

Perhaps a more salient question would be, what is the strength of the Poynting vector force over one-half cycle as that should be the maximum Poynting force attainable, and how does it compare to F = 2PQ/c?

Only the Experimental EM Drive used an internal small end dielectric. As a result, it had low Q and low thrust.

The Demonstrator and Flight Thruster EM Drives are high Q and high thrust devices which did not use a dielectric.

Shawyer says using a dielecrtic:

1) increases loss,

2) reduces Q,

3) reduces thrust.

His reported results back up that claim

So why the interest in dielectrics?

Why not? Would you be satisfies if I wrote, "and the existance or not of the dielectric"?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: Rodal on 05/28/2015 09:54 PM
Quote
EDIT: Oh, by the way, the Poynting vector frequency is always twice the frequency of the electromagnetic field, its period is 1/2  the period of the electromagnetic field. It reverses direction twice as often as the electromagnetic fields.
So the Poynting vector is an even number of cycles no matter the number of half-cycles of the drive frequency. Well, next we ask, is the drive frequency (period, wavelength) always an interger number of half-cycles?

Seems it must be in order to resonate but the shape of the cavity and the existance of the dielectric makes one wonder, what is the effective drive frequency as far as the Poynting vector is concerned and does it remain always an even number of cycles everywhere within the cavity?

Perhaps a more salient question would be, what is the strength of the Poynting vector force over one-half cycle as that should be the maximum Poynting force attainable, and how does it compare to F = 2PQ/c?

Only the Experimental EM Drive used an internal small end dielectric. As a result, it had low Q and low thrust.

The Demonstrator and Flight Thruster EM Drives are high Q and high thrust devices which did not use a dielectric.

Shawyer says using a dielecrtic:

1) increases loss,

2) reduces Q,

3) reduces thrust.

His reported results back up that claim

So why the interest in dielectrics?

First read this:  http://forum.nasaspaceflight.com/index.php?topic=37642.msg1381229#msg1381229 which should answer your question.  Besides that post, there are respectable people in the aerospace community, outside this thread who have the following opinion:

1) NASA's experiments have falsified the results reported by Shawyer and NWPU
2) NASA only measured thrust using a dielectric insert.  No thrust measured without it.

I think that it is important for NASA at some point to conduct further experiments without a dielectric and using a magnetron at higher power as they intended to do, to clarify this situation. I am not convinced about the test without a dielectric because:
a) it was conducted very early in NASA's testing program
b) only a test was performed
c) it involved mode TE012 which, according to Brady's report, was difficult to replicate even with a dielectric, so they had to move on to mode TM212 which was never tested yet without a dielectric.

 It is also important to carry on with the testing program as envisioned by Dr. White, involving replication of the experiments at NASA Glenn.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: deltaMass on 05/28/2015 10:02 PM
Have asked Roger Shawyer to confirm the quoted Df for the Demonstrator EMDrive is 0.844:

http://emdrive.com/demonstratorengine.html
Can you please ask for him to check his original data documents (rather than his published papers) , and re-calculate the Design Factor based on known geometry, to make sure that there was not an unintended typo somewhere?

From work on my spreadsheet, that can easily adopt to various TMm,n and TEm,n modes, I believe it is possible to get an excitation mode that will deliver a high Df, small end operating just above cutoff (as Shawyer recommends), without using stupid geometry.

Did ask for the excitation mode. If he shares that, will be able to plug it into my spreadsheet and see what it says about small diameter.

The more I work with my spreadsheet, the more I get a good gut feeling about how the 3 dimensions, excitation mode and external Rf frequency interplay with each other to get an optimal mix of all 5 variables for max thrust per applied power.
Have you shared your spreadsheet here? If you do, I can possibly help out with the optimisation
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/28/2015 10:29 PM
Flight Thruster build update:

From the best photo of the Flight Thruster I could find and allowing for 2mm thick walls, to add thermal mass and reduce the rate of thermal expansion, the following internal Flight Thruster dimensions were obtained:

Length:   138.6mm
Small diameter:   125.7mm
Big diameter:   231.4mm

Applying those to my spreadsheet generated:

Df:   0.638
Frequency:   3.85GHz
Mode:   TE013

I then asked Roger Shawyer did I get close? His reply:

Df:  0.635
Frequency:   3.9003GHz
Mode:   TE013

I'm VERY happy with that as my Rf gen can easily go to that frequency. Time now to finalise drawings and get some copper sheet laser cut.

Roger also mentioned it is best to give the internal frustum surfaces a nice bright shinny polish. No need for Silver or Gold overcoats.

Will the end-plates be removable in your design? Can you do an experiment, attaching some Ferrite blocks or Metglass to the inside surface of the "big" end?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: PaulF on 05/28/2015 10:33 PM
so, no scat, there i was... I learned you can do stuff that violates the laws of physics so long as you label the process as happening in imaginary time even if it has real physical consequences.

http://phys.org/news/2015-05-physicists-quantum-tunneling-mystery.html (http://phys.org/news/2015-05-physicists-quantum-tunneling-mystery.html)

Synopsis: Massive things that quantum tunnel can violate the physical speed limit of light so long as there isn't anybody watching and there cannot be anyone watching because it happens in imaginary time.

I don't know about you; but i kind of had a different idea of what "imaginary" means but evidently imaginary does NOT mean unreal.
To put another spin on this, what intrigued me was their interpretation of gravity. Maybe someone could elaborate if they think they grasp this information, but in my phylisophical head I get the notion that gravity may be another physical dimension coupled to our 4 spacetime dimensions. Or a brane that intersects our 4D spacetime brane (if one wants to relate it to string or brane theory) in a certain way that this could be the mechanism that made the gravitational constant what it is. Or maybe it is parallel to our brane and has a set distance accounting for the grav. constant.

I am not saying gravity is not the effect of mass warping spacetime. Just to be clear.

Or am I thinking way too out there?
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: PaulF on 05/28/2015 10:40 PM

Roger also mentioned it is best to give the internal frustum surfaces a nice bright shiny polish. No need for Silver or Gold overcoats.

Hah! I wondered that same thing last week. I mentioned this here but nobody replied on it so I don't know if it was picked up.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/28/2015 10:42 PM
...Would TE011 actually work? 2.37GHz is below the TE01 cutoff frequency of 2.9GHz for a cylindrical waveguide of the small end (125cm).   
TE011 is actually not cut-off according to the exact solution with spherical ends for those dimensions listed above (125.7mm).   It looks good and strong, very clear signal in the exact solution.

It would have higher attenuation at the small end, which according to Todd's theory -which has my seal of approval  :) - is a plus.

I suppose that those that think that attenuation is bad may opt against, but it would be nice to test.

The only advantage I see with TE013 is that it has the Poynting vector concentrated at the small end, and a local high amplitude at the small end.

Hey Todd (WarpTech), we need to get your theory written up and in the Wiki http://emdrive.echothis.com/Theory

I hear you! Not enough hours in the day, I'm afraid.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: rfmwguy on 05/28/2015 11:35 PM
I've read engineering management papers about multi-national, multi-disciplined collaborative engineering efforts via the internet, but have never seen them in practice like this until I started reading NSF EM thread #1. I'll join others and give kudos to all and special thanks to Doc Rodal and Chris Bergan for managing/making the threads available. Keep in mind EMDrive is not a classic nuts & bolts engineering issue, but a leading-edge  project...the "effect" is there and while it might be explained or disproven someday, people here can rest assured their serious efforts will not go unnoticed.

Just a little pick-me-up for those whose brains have been pushed to the "outer limits".  :o
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/29/2015 12:16 AM
Quote
EDIT: Oh, by the way, the Poynting vector frequency is always twice the frequency of the electromagnetic field, its period is 1/2  the period of the electromagnetic field. It reverses direction twice as often as the electromagnetic fields.
So the Poynting vector is an even number of cycles no matter the number of half-cycles of the drive frequency. Well, next we ask, is the drive frequency (period, wavelength) always an interger number of half-cycles?

Seems it must be in order to resonate but the shape of the cavity and the existance of the dielectric makes one wonder, what is the effective drive frequency as far as the Poynting vector is concerned and does it remain always an even number of cycles everywhere within the cavity?

Perhaps a more salient question would be, what is the strength of the Poynting vector force over one-half cycle as that should be the maximum Poynting force attainable, and how does it compare to F = 2PQ/c?

Only the Experimental EM Drive used an internal small end dielectric. As a result, it had low Q and low thrust.

The Demonstrator and Flight Thruster EM Drives are high Q and high thrust devices which did not use a dielectric.

Shawyer says using a dielecrtic:

1) increases loss,

2) reduces Q,

3) reduces thrust.

His reported results back up that claim

So why the interest in dielectrics?

Why not? Would you be satisfies if I wrote, "and the existance or not of the dielectric"?

My 1st phase is replication, not experimentation.

Have no interest in building anything other than a Flight Thruster that is as close to the unit SPR built as possible. Too many unknowns to start changing things before I have a solid data base to go forward from.

There was no dielectric in either the Demonstrator or Flight Thruster, so there will be no dielectric in my 1st build.

As my design allows for end plate changes, I may experiment with dielectrics once I have established a soild operational unit.

Would not modify the 1st unit as it will become my control or standard unit. Would built another unit for experimentation.

1st phase Replication,
2nd phase Experimentation.

A 100W 3.85GHz Rf amp will dent the budget by $4,000 if I go with MiniCircuit unit. Have started searching ham resources for a lower cost unit.

Suggestions on other 100W 3.5-4.0GHz amps most welcome.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: WarpTech on 05/29/2015 12:27 AM
This was a thought occurring me a moment ago. I have just shown that inside these cavities there is a tiny gravitational effect. Per se this effect is too small account for the observed thrust, if confirmed. But, is there any change in the light propagation inside such cavities causing an asymmetry due to these small gravitational effects?
Yes.
Change gravity-> change a fundamental of space-> change time.

Personally Im still stuck in the "energy density" conundrum. If we think of space as a support mechanism acting in such a manner as to be a "carrier" of energy, and we alter an aspect of space then the energy being carried must also be impacted in some form. In stronger gravity fields spectral lines change as atoms are more compressed and molecules move more rapidly, Refraction would change. Extreme examples would be black holes.

QUESTION: What would you expect to happen to a light beam originating in normal space (the lab) traversing through a modified area of space (inside the cavity) and exiting the modified area back into normal space. Freuency shift? polarization shift?... or nothing because its back in normal space and we cant measure/detect a change

Shining a laser through a small hole in the base and top of a cavity "might" display transverse spectral changes?.  Or have 2 holes in the base and a small internal mirror attached to the cavity top...

It "might" be interesting to have a straight line of small holes directly down each side of a cavity allowing a laser to traverse directly through the cavity. Shifting the laser sequentially from bottom to top may reveal a difference in cavity internal events (or not)?.

EM waves propagating through free space reach a waveguide, what comes out the other side will depend on the dimensions and orientation of the waveguide, its conductivity, length, etc... If the dimensions of the waveguide are much smaller than the wavelength of the wave in free space, it won't pass through it. If it does pass through it, its speed will vary depending on wavelength, and the wave's phase and polarization can be altered by passing through the waveguide as well. There are twisted waveguides for just this purpose.

In GR, the stress energy tensor is what yields gravity. In EM, that tensor represents energy/momentum stored or energy/momentum flowing. The refractive index of the vacuum is also a representation of how much energy "can" be stored. Inductance & Capacitance represent those variables, they store EM energy, and in free space are represented by mu0 and eps0;

c = 1/sqrt(mu0*eps0)

The refractive index in a gravitational field, K depends on the relative values of mu and eps,

c/K = 1/sqrt(mu_rel*eps_rel)

Illustrating that the speed depends on the inductive and capacitive properties of the vacuum, that give it the ability to store the EM wave's energy. In the frustum cavity, as in a waveguide, more energy can be stored than in free space, so the velocity is slower. However, the effect is wavelength dependent, where gravity is not.

As I've said, the frustum mimics gravity over a narrow bandwidth, very well. This effect is many orders of magnitude larger than the effect predicted in Marco's paper. I think it will overwhelm any experimental evidence of the latter.

Todd


Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/29/2015 01:02 AM
...A 100W 3.85GHz Rf amp will dent the budget by $4,000 if I go with MiniCircuit unit. Have started searching ham resources for a lower cost unit.

Suggestions on other 100W 3.5-4.0GHz amps most welcome.
Suggestion: start by exciting TE011 at 2.4 GHz which should be cheaper and more effective than TE013.  Look at @Notsosureofit's equation http://emdrive.echothis.com/@notsosureofit_Hypothesis (more sophisticated approach than Shawyer's)

Mode:   TE011
Frequency:   2.37833 GHz

Replicate 1st
Experiment 2nd.

Yea I know dull and boring but in my experience, when doing something very new and new to me, replication wins out at the end of the day.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/29/2015 01:06 AM
Flight Thruster build update:

From the best photo of the Flight Thruster I could find and allowing for 2mm thick walls, to add thermal mass and reduce the rate of thermal expansion, the following internal Flight Thruster dimensions were obtained:

Length:   138.6mm
Small diameter:   125.7mm
Big diameter:   231.4mm

Applying those to my spreadsheet generated:

Df:   0.638
Frequency:   3.85GHz
Mode:   TE013

I then asked Roger Shawyer did I get close? His reply:

Df:  0.635
Frequency:   3.9003GHz
Mode:   TE013

I'm VERY happy with that as my Rf gen can easily go to that frequency. Time now to finalise drawings and get some copper sheet laser cut.

Roger also mentioned it is best to give the internal frustum surfaces a nice bright shinny polish. No need for Silver or Gold overcoats.

Will the end-plates be removable in your design? Can you do an experiment, attaching some Ferrite blocks or Metglass to the inside surface of the "big" end?

Yes both end plates are removable. Will however not modify the 1st test unit (after it is operational) as that will become my control or standard baseline unit.
Title: Re: EM Drive Developments - related to space flight applications - Thread 3
Post by: TheTraveller on 05/29/2015 01:20 AM
...A 100W 3.85GHz Rf amp will dent the budget by $4,000 if I go with MiniCircuit