Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1805140 times)

Offline wallofwolfstreet

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@TheTraveller

In regards to the abstract of Shawyer's paper, which you posted to reddit and Rodal has posted to this forum, I have a specific question:

When Shawyer says:
Quote
The engines are based on YBCO superconducting cavities, and performance is predicted on the basis of the test data obtained in earlier experimental programmes.

Are those new experimental programme results (ie. data we haven't seen before), or eariler in the sense that they have already been released?

I sincerely hope the former.  Otherwise this paper is just more blue sky dreaming, and would really constitute more of a sales pitch than an actual scientific paper.

Offline rfmwguy

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EMDIYers Word O' the Day: Apophenia

"is the experience of perceiving patterns or connections in random or meaningless data." - https://en.wikipedia.org/wiki/Apophenia

Moral of the day? Get your test results up out of the noise to show clear trends.  8)

Offline TheTraveller

@TheTraveller

In regards to the abstract of Shawyer's paper, which you posted to reddit and Rodal has posted to this forum, I have a specific question:

When Shawyer says:
Quote
The engines are based on YBCO superconducting cavities, and performance is predicted on the basis of the test data obtained in earlier experimental programmes.

Are those new experimental programme results (ie. data we haven't seen before), or eariler in the sense that they have already been released?

I sincerely hope the former.  Otherwise this paper is just more blue sky dreaming, and would really constitute more of a sales pitch than an actual scientific paper.

More info when full paper is published.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline matthewpapa

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So is that a no?

Or a no comment :)


Offline TheTraveller

So is that a no?

Or a no comment :)

You need to wait for the peer reviewed paper to be released.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline francesco nicoli

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honestly I don't get it @Traveller. He is not asking you the results. He is not asking info about setups, contents, models. He is simply asking whether is new experiments or not. For the sake of this discussion and nothing else. You would certainly not violate any copyright norm if you tell us whether there are new experiments or not- actually, this is a normal information that should be stated in the abstract.

Offline wallofwolfstreet

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So is that a no?

Or a no comment :)

You need to wait for the peer reviewed paper to be released.

But you have read the paper, correct? 

I understand we have to wait for the paper to be released to see the data.  I just want to know if the data in the paper has or has not been released before.  It's just a yes or no question. No need to link any data, because I know you have to respect Roger's wishes and any deals you two have. 

Offline TheTraveller

So is that a no?

Or a no comment :)

You need to wait for the peer reviewed paper to be released.

But you have read the paper, correct? 

I understand we have to wait for the paper to be released to see the data.  I just want to know if the data in the paper has or has not been released before.  It's just a yes or no question. No need to link any data, because I know you have to respect Roger's wishes and any deals you two have.

The paper SPR submitted for peer review has not been publicly released. It is not available on the SPR web site. It has new information to that available on the SPR website.
« Last Edit: 06/25/2015 02:59 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline SeeShells

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...Several hundred quotes ago you, Thetraveler and a host of others joined in to do some not so simple calculations for a truncated cone. they all kind of worked and you all agreed to disagree, and now we have meep telling us something else...
Concerning the predicted natural frequency and mode shape, based on my experience with Finite Difference methods at MIT (where Meep was written) the difference may be due to the discretization model and not due to a physical difference or due to a difference with Meep from other codes.  It is known that Finite Elements have much better convergence properties than Finite Difference methods (for the same number of grid points), since FE are based on variational principles and use polynomial interpolation in between.  It simply appears that the FD mesh discretization is far from being sufficient to provide convergence.  @aero writes that it is due to his computer memory and time limitations. 

This issue is well known to people familiar with FD methods, for example in fluid mechanics, where finite difference methods were prevalent.  Whenever undertaking a numerical solution, the user should:


1) conduct comparisons between the meshed solution and a known closed-form solution (in this case a comparison with a cylinder's natural frequencies)

2) conduct a convergence study of finer and finer meshes to ascertain the rate of convergence, and whether there is any monotonic convergence to a solution.


Part of the problem is due to the enforcement of boundary conditions based on Cartesian coordinates for a problem that has circular axi-symmetry (this is evident from the fractal artifact on the FD solution showing the fact that the FD mesh is not fine enough).  The problem of FD methods with boundary conditions is well-known and it is one of the reasons that FE and other methods were developed.  Yet, FD's advantage is due to the simplicity in coding FE codes, and the fact that one does not have to deal with a more fully populated huge matrix that has to be inverted (as in the FE method).
Thank you for detailing it out I very much appreciate it.

On models... it's true Jose and if we were better at our models we would have had a operational fusion reactor long ago. ;) But, they are good enough to give us CERN aren't they? We're not dealing with a particle accelerator cavity are we (or maybe we are)? It's just a copper capped off cone shaped enclosure, just a slight deviation from a symmetrical resonating cavity and it should as easy as ringing a bell, it's not. HA!... like striking a large bell and hearing Johann Strauss's "The Blue Danube" over the ringing and that would be a good analogy.

 

Offline JasonAW3

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     It may be possible that we may be missing some fundemental principle or function that cannot be fully observed in a gravity well.   While parabolic arc flights and microgravity experiments on the ISS may provide more information, I suspect that if there is some fundemental, quantum level phenomena occuring that is enabling the results that we are currently observing with the EM drive tests, then we likely won't really uncover the full extent of this until we test this system in an area of spece wher gravity is largely canceled out, like EML-4 or EML-5.

     Yes, getting a test syystem to that location would be hidiously expensive, but if there are results that seem to be very promising, I don't really think we'll fully understand what is going on until gravity can be effectively eliminated as a factor.
My God!  It's full of universes!

Offline Rodal

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...
Thank you for detailing it out I very much appreciate it.

On models... it's true Jose and if we were better at our models we would have had a operational fusion reactor long ago. ;) But, they are good enough to give us CERN aren't they? We're not dealing with a particle accelerator cavity are we (or maybe we are)? It's just a copper capped off cone shaped enclosure, just a slight deviation from a symmetrical resonating cavity and it should as easy as ringing a bell, it's not. HA!... like striking a large bell and hearing Johann Strauss's "The Blue Danube" over the ringing and that would be a good analogy.

We should not conflate the claims about "thrust" from the EM Drive to whether we can accurately model the natural frequency and mode shapes.  Is this being conflated because of deltaMass question?

We know for a fact that the natural frequency and mode shapes of these truncated cones can be accurately predicted with Finite Element, Finite Difference and exact solutions.  There is no doubt whatsoever about it.  Any difference in predictions is due to issues with people's models.

There is no room here for misinterpretation:  the natural frequencies and mode shapes that have been accurately predicted for complicated-geometry resonators at CERN, and other cases, including asymmetric cavities, based on Finite Element Analysis are correct.

There is absolutely nothing in the EM Drive experimental reports pointing towards any inadequacy of Maxwell's equations to predict natural frequencies and mode shapes.  On the contrary, NASA experiments confirm the accuracy of the FEA solutions

There are plenty of articles that have been written about resonance of truncated cones (please take a look at the references in my paper of extended pointy cone geometries).  They all agree concerning resonance.  Nobody I know of claims that Maxwell's equations are incorrect to predict resonance of a truncated cone cavity excited with at microwave frequencies.

If there is thrust from these cavities is a different question that should not be conflated with cavity resonance based on a solution to Maxwell's equations.  I would be surprised if deltaMass was trying to infer that the natural frequency and mode shape calculations performed at CERN for complicated geometry cavities are wrong.

I think that deltaMass was addressing the thrust claims, and not the natural frequency or mode shape calculations.  I think that deltaMass was questioning whether numerical analysis of Maxwell's equations can throw any light on the claimed "thrust". 

_______

As per your example, if somebody would claim that they can use  a plastic Coke bottle for propulsion (which can be done: acoustic propulsion) that doesn't change the accuracy of predicting the acoustic frequency of a Coke bottle.  On the contrary, the accuracy of predicting acoustic frequency of Coke bottles is intact:


« Last Edit: 06/25/2015 03:25 PM by Rodal »

Offline SeeShells

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EMDIYers Word O' the Day: Apophenia

"is the experience of perceiving patterns or connections in random or meaningless data." - https://en.wikipedia.org/wiki/Apophenia

Moral of the day? Get your test results up out of the noise to show clear trends.  8)
Yep and if  my 800 watts won't do it I might react like the Myth Busters and get a high power surplus klystron from ebay and run it till it slags.
 

Offline wallofwolfstreet

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So is that a no?

Or a no comment :)

You need to wait for the peer reviewed paper to be released.

But you have read the paper, correct? 

I understand we have to wait for the paper to be released to see the data.  I just want to know if the data in the paper has or has not been released before.  It's just a yes or no question. No need to link any data, because I know you have to respect Roger's wishes and any deals you two have.

The paper SPR submitted for peer review has not been publicly released. It is not available on the SPR web site. It has new information to that available on the SPR website.

Sorry to pester you, but that was a non-answer on the level of any talented marketing agent.

I have no doubt it contains new information, as anything I don't already know is new information to me.  I didn't know what the acronym SSTO meant until just now, for example.
 
I am asking:  Are the projections in that paper based on new, not released, experimental data?  Yes or no. 

Offline rfmwguy

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EMDIYers Word O' the Day: Apophenia

"is the experience of perceiving patterns or connections in random or meaningless data." - https://en.wikipedia.org/wiki/Apophenia

Moral of the day? Get your test results up out of the noise to show clear trends.  8)
Yep and if  my 800 watts won't do it I might react like the Myth Busters and get a high power surplus klystron from ebay and run it till it slags.

Shell, you might be surprised about the resolution of the fulcrum test methodology. For example, I am tweaking mine for much higher resolution, increasing laser path length, oil dampening, stiffening, etc. Reason I did this is that the Q of my cavity may be much less than spreadsheet land...IOW, I'm planning for 1/10 the resolution I started out with @ 8W. So at 800W, you might launch that puppy  ;)

Offline TheTraveller

...
Thank you for detailing it out I very much appreciate it.

On models... it's true Jose and if we were better at our models we would have had a operational fusion reactor long ago. ;) But, they are good enough to give us CERN aren't they? We're not dealing with a particle accelerator cavity are we (or maybe we are)? It's just a copper capped off cone shaped enclosure, just a slight deviation from a symmetrical resonating cavity and it should as easy as ringing a bell, it's not. HA!... like striking a large bell and hearing Johann Strauss's "The Blue Danube" over the ringing and that would be a good analogy.

We should not conflate the claims about "thrust" from the EM Drive to whether we can accurately model the natural frequency and mode shapes.  Is this being conflated because of deltaMass question?

We know for a fact that the natural frequency and mode shapes of these truncated cones can be accurately predicted with Finite Element, Finite Difference and exact solutions.  There is no doubt whatsoever about it.  Any difference in predictions is due to issues with people's models.

There is no room here for misinterpretation:  the natural frequencies and mode shapes that have been accurately predicted for complicated-geometry resonators at CERN, and other cases, including asymmetric cavities, based on Finite Element Analysis are correct.

There is absolutely nothing in the EM Drive experimental reports pointing towards any inadequacy of Maxwell's equations to predict natural frequencies and mode shapes.  On the contrary, NASA experiments confirm the accuracy of the FEA solutions

There are plenty of articles that have been written about resonance of truncated cones (please take a look at the references in my paper of extended pointy cone geometries).  They all agree concerning resonance.  Nobody I know of claims that Maxwell's equations are incorrect to predict resonance of a truncated cone cavity excited with at microwave frequencies.

If there is thrust from these cavities is a different question that should not be conflated with cavity resonance based on a solution to Maxwell's equations.  I would be surprised if deltaMass was trying to infer that the natural frequency and mode shape calculations performed at CERN for complicated geometry cavities are wrong.

I think that deltaMass was addressing the thrust claims, and not the natural frequency or mode shape calculations.  I think that deltaMass was questioning whether numerical analysis of Maxwell's equations can throw any light on the claimed "thrust". 

_______

As per your example, if somebody would claim that they can use  a plastic Coke bottle for propulsion (which can be done: acoustic propulsion) that doesn't change the accuracy of predicting the acoustic frequency of a Coke bottle.  On the contrary, the accuracy of predicting acoustic frequency of Coke bottles is intact:



Still waiting for your TE013 mode resonant frequency for my Flight Thruster dimensions?
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline Rodal

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...Still waiting for your TE013 mode resonant frequency for my Flight Thruster dimensions?
please provide (there are multiple dimensions, and I need you to clearly specify them again):

BIG DIAMETER =   meters
SMALL DIAMETER =   meters
AXIAL Length =   meters

where axial length is measured in the longitudinal direction perpendicular to the bases.

When provided I'll give you an answer within a couple of days.

If interested in the accuracy of your spreadsheet, you can compare with the 21 frequencies predicted by COMSOL FEA, as I have done here http://forum.nasaspaceflight.com/index.php?topic=37642.msg1393872#msg1393872

and to my calculations on my report on cut-off frequencies of truncated cones.

___________

EDIT: Thanks to kdhilliard for catching the mistake I made with a redundant "DIAMETER" word where it did not belong :)
« Last Edit: 06/25/2015 07:17 PM by Rodal »

Offline hhexo

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When you pull it forward, it's lighter. When you push it backwards, it's heavier. An external sin(wt) oscillation will have a NET DC offset. LOL! That's hilarious!

The engineer in me still doesn't see this cruising among the stars...

If I understand correctly, this is equivalent to saying that the inertial mass of the device appears different in different directions. We can visualize it with a surface which normally is a sphere of radius m0, but which is distorted when the resonant microwaves are on, to a surface that is still radially symmetrical around the z axis but asymmetrical with respect to the xy plane. The modulus of the points on the surface determines the effective inertial mass mv (with v being the vector to the point - for each interaction you have to take the vector that's aligned with the force).

Am I correct in saying that this theory then intentionally breaks the equivalence principle? That gravitation (like any other force) would use the standard mass m0 but inertia would use an mv on the distorted surface?
I'm not inherently opposed to it, I'm just checking, is this what the theory implies?

If this theory was correct, then:
- When the device is on a scale and powered on, it would weigh more or less depending on how it's oriented, because gravitational mass would be different from inertial mass. This would explain the static results on scales, which would not be the result of thrust, but only of a perceived mass difference.
- When the device is free to move and powered on, it would resist accelerations differently in different directions. Given a vibration pattern, there would be a net movement in one direction.
- The device would not be a thruster on its own, but only an inertial dampener/booster.

The energy required for this inertial dampening would come from the power supply; I would wager that for CoE the energy that you spend for the inertia change is at least equal (but likely higher) to what you would have spent propelling the reaction mass that you didn't need to propel. So it basically saves reaction mass but doesn't save energy, it just allows you to use electric energy directly without reaction mass.

Even if we roll with it though, the engineer in me says that it still does not make space propulsion much easier. As far as I can see the device can only change the inertial mass of the device itself, not of the ship around it. Even supposing we power it with an insane amount of energy and reduce the EmDrive inertial mass to zero in one direction... it doesn't reduce the total inertial mass of the spaceship by much.

Unless it can reduce its inertial mass to negative values, but that's even more exotic and definitely in the realm of spacetime warp.

Offline Star One

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So is that a no?

Or a no comment :)

You need to wait for the peer reviewed paper to be released.

But you have read the paper, correct? 

I understand we have to wait for the paper to be released to see the data.  I just want to know if the data in the paper has or has not been released before.  It's just a yes or no question. No need to link any data, because I know you have to respect Roger's wishes and any deals you two have.

The paper SPR submitted for peer review has not been publicly released. It is not available on the SPR web site. It has new information to that available on the SPR website.

Sorry to pester you, but that was a non-answer on the level of any talented marketing agent.

I have no doubt it contains new information, as anything I don't already know is new information to me.  I didn't know what the acronym SSTO meant until just now, for example.
 
I am asking:  Are the projections in that paper based on new, not released, experimental data?  Yes or no.

Not to fight his battles for him, but he is not obligated to answer that question on something like this and you should know better than to be even asking.

Offline TheTraveller

When you pull it forward, it's lighter. When you push it backwards, it's heavier. An external sin(wt) oscillation will have a NET DC offset. LOL! That's hilarious!

The engineer in me still doesn't see this cruising among the stars...

If I understand correctly, this is equivalent to saying that the inertial mass of the device appears different in different directions. We can visualize it with a surface which normally is a sphere of radius m0, but which is distorted when the resonant microwaves are on, to a surface that is still radially symmetrical around the z axis but asymmetrical with respect to the xy plane. The modulus of the points on the surface determines the effective inertial mass mv (with v being the vector to the point - for each interaction you have to take the vector that's aligned with the force).

Am I correct in saying that this theory then intentionally breaks the equivalence principle? That gravitation (like any other force) would use the standard mass m0 but inertia would use an mv on the distorted surface?
I'm not inherently opposed to it, I'm just checking, is this what the theory implies?

If this theory was correct, then:
- When the device is on a scale and powered on, it would weigh more or less depending on how it's oriented, because gravitational mass would be different from inertial mass. This would explain the static results on scales, which would not be the result of thrust, but only of a perceived mass difference.
- When the device is free to move and powered on, it would resist accelerations differently in different directions. Given a vibration pattern, there would be a net movement in one direction.
- The device would not be a thruster on its own, but only an inertial dampener/booster.

The energy required for this inertial dampening would come from the power supply; I would wager that for CoE the energy that you spend for the inertia change is at least equal (but likely higher) to what you would have spent propelling the reaction mass that you didn't need to propel. So it basically saves reaction mass but doesn't save energy, it just allows you to use electric energy directly without reaction mass.

Even if we roll with it though, the engineer in me says that it still does not make space propulsion much easier. As far as I can see the device can only change the inertial mass of the device itself, not of the ship around it. Even supposing we power it with an insane amount of energy and reduce the EmDrive inertial mass to zero in one direction... it doesn't reduce the total inertial mass of the spaceship by much.

Unless it can reduce its inertial mass to negative values, but that's even more exotic and definitely in the realm of spacetime warp.

A PM motor has 3 modes.

No power applied and no movement.

Apply power & it rotates.

Non shorted & non powered input and motor shaft rotates freely.

Short the input and shaft rotation is resisted.

The EMDrive is a different breed of dog but has the same leg action.

Non powered EMDrive can move either direction.

Powered it resists movement in one direction but not the other due to differential internal Doppler shifts of the resonant standing wave inside the cavity.
« Last Edit: 06/25/2015 04:06 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline Rodal

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..
Not to fight his battles for him, but he is not obligated to answer that question on something like this and you should know better than to be even asking.
I strongly disagree.   TheTraveller started this by posting in this thread that Shawyer was going to publish an article in a peer-reviewed journal, and made a number of statements based on his privileged status of having the unique opportunity of having read the article ahead of publication.  Nobody asked or forced TheTraveller to post about Shawyer's future article.  Now TheTravellerEMD publishes the abstract of the paper.
WallofWolfStreet is entirely correct to ask TheTraveller about this abstract vis-a-vis TheTraveller's previous posts on this thread concerning the article he claims to have read ahead of publication.

As stated on page 1 of this thread, this thread is not a site for public advertising or promotions.

If TheTraveller does not want to discuss this or respond to WallofWolfStreet question, what was the purpose of TheTraveller's posting the fact that he had read Shawyer's upcoming article ?
« Last Edit: 06/25/2015 04:14 PM by Rodal »

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