Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1880580 times)

Offline DrBagelBites

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How to waste precious time on the build - spent 4hrs trying to get the cheap 100mw exciter to fire up...junk from china without an online manual. Its not the ten bucks, its the time wasted. Moral of story, get a well documented board or module. Forget troubleshooting, surface mount components, electronics hardware is throw away stuff now, which I just did >:(

Sorry to hear that, rfmwguy.

I'm awaiting to see if I will soon be in the same boat with the stuff I ordered as well.

I don't know when I'll learn that you can't afford to go cheap. ;)
Funny thing is the cheapest module caused the problem. No big deal, 2.4ghz stuff is in every store and easy to obtain which is a big plus. Let u know what I substitute in there...probably a teardown of a wifi cam. Most all are 100mw.

Could also look into remote control things as well. They run on 2.4 GHz most of the time as well. Pretty cheap stuff definitely.

Offline VAXHeadroom

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And what the heck, just stack them all up at once. :)

Emory Stagmer
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Offline Devilstower

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Those pointing up Shawyer's outlay as compared to those attempting to replicate his experiments might want to note this: Shawyer did it first.

In many areas of research, there is definitely a first-mover disadvantage.  It's the first person on the path that chases down blind alleys, deals with cobbled together instrumentation, and makes do with custom-machined components. All of these things tend to be much simpler for those who come after.  The availability of high-quality measurement devices in consumer-grade equipment has also greatly affected costs over the last few years. I've seen people expend many millions hardwiring experimental gear, that just a few years later could be bettered with an iPad and off the shelf components.

All this is just to say—everyone is now trying to reproduce what appears to be Shawyer's best design. I doubt we have the full catalog of his failures.

Offline WarpTech

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How to waste precious time on the build - spent 4hrs trying to get the cheap 100mw exciter to fire up...junk from china without an online manual. Its not the ten bucks, its the time wasted. Moral of story, get a well documented board or module. Forget troubleshooting, surface mount components, electronics hardware is throw away stuff now, which I just did >:(

Sorry to hear that, rfmwguy.

I'm awaiting to see if I will soon be in the same boat with the stuff I ordered as well.

I don't know when I'll learn that you can't afford to go cheap. ;)
Funny thing is the cheapest module caused the problem. No big deal, 2.4ghz stuff is in every store and easy to obtain which is a big plus. Let u know what I substitute in there...probably a teardown of a wifi cam. Most all are 100mw.

I know how you feel, but I just found out that the surface resistance of copper at 2.4GHz is supposedly,

RS = 0.013 Ohms.

From this, you can get the power losses as the integral over the internal surface area,

P_loss = ∮S(RS*|H|2)*dS, Basically Ohm's law.

That's a pretty high resistance, so a 100mW source will hardly overcome the copper losses. Based on the heating reported, the losses are in the "watts" range at high Q. I'm sure you will need a stronger source.
Todd

Offline deltaMass

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I think you mean resistivity in Ohm-metres, don't you? You ought to mean that, anyway!

Offline DrBagelBites

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I know how you feel, but I just found out that the surface resistance of copper at 2.4GHz is supposedly,

RS = 0.013 Ohms.

From this, you can get the power losses as the integral over the internal surface area,

P_loss = ∮S(RS*|H|2)*dS, Basically Ohm's law.

That's a pretty high resistance, so a 100mW source will hardly overcome the copper losses. Based on the heating reported, the losses are in the "watts" range at high Q. I'm sure you will need a stronger source.
Todd

I think he is planning on using an amplifier to up power to 8W, I believe.

Online SeeShells

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Those pointing up Shawyer's outlay as compared to those attempting to replicate his experiments might want to note this: Shawyer did it first.

In many areas of research, there is definitely a first-mover disadvantage.  It's the first person on the path that chases down blind alleys, deals with cobbled together instrumentation, and makes do with custom-machined components. All of these things tend to be much simpler for those who come after.  The availability of high-quality measurement devices in consumer-grade equipment has also greatly affected costs over the last few years. I've seen people expend many millions hardwiring experimental gear, that just a few years later could be bettered with an iPad and off the shelf components.

All this is just to say—everyone is now trying to reproduce what appears to be Shawyer's best design. I doubt we have the full catalog of his failures.
I understand he saw an anomaly when he was doing work for the military on the communications with some of the missiles and it came down to the radar in the missiles communications equipment. By accident he found it from another effect.  I heard this in an interview some time back.

Shell

Offline Vix

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There are some great inventions that have been found "by accident". And we must not forget that often these scientists were ridiculed then, because their fellows just could't grasp it. I see history repeating...

Online SeeShells

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And what the heck, just stack them all up at once. :)


Wow, that's almost too much at once! I needed to stare at it for the longest time to see patterns of relationships. Nice work. Thanks!
Shell

Offline deuteragenie

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Quote
...
We need NUMBERS to quantify this, there is no other way around it.  Without numbers one cannot compare.

At least now we have everything scaled to the same Max Min numbers, unfortunately we don't know the numbers.

Can you tell aero how to output NUMBERS in Meep?

1. Define a region where flux is to be measured

(define wvg-pwr (add-flux f 0 1
    (make flux-region (direction Z) (center 0 0)
       (size (* 1.2 (+ (* 2 sw) s)) (* 1.2 sw) 0))))

2. Display the fluxes (the output will be as CSV), in the run-until section:

(display-fluxes wvg-pwr)


I have successfully tested this example: http://ab-initio.mit.edu/wiki/index.php/Meep_Tutorial, and am running the same Meep version as aero, under the same operating system.

Agree with aero: if someone could produce a .deb package with the latest sources and dependencies included, that would be great!

« Last Edit: 06/29/2015 07:42 AM by deuteragenie »

Offline OttO

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I think the traveller will like this article when he feels better:

Direct determination of the resonance properties of metallic conical nanoantennas

http://www.researchgate.net/profile/Carlo_Liberale/publication/260040081_Direct_determination
_of_the_resonance_properties_of_metallic_conical_nanoantennas/links/5476ccbd0cf2778985b08312.pdf


"A cone can be envisioned as a continuous sequence of coaxial cylinders with decreasing radii. Under the local
mode concept, valid for slowly varying structures [21], within local domains the plasmonic cylinder modes are
good approximations to the solutions of the Maxwell’s equations."
« Last Edit: 06/29/2015 11:40 AM by Chris Bergin »

Offline Chrochne

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I just read Mr. Traveller claim on reddit that the vibration increase the thrust of the EmDrive. May I ask you folks if there was already a debate about it here? I would be glad to read about it bit more.

Did anybody here tried to increase the vibration in order to increase thrust? I would be glad to check that as well :).

Quote:

Vibration is everywhere.

Vibratory movement causing small end to big end movement will be opposed by the EMDrive.

Vobratory movement causing Big end to small end movement will be supported by the EMDrive.

Please understand what Roger Shawyer has said:

"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.

UK flight thruster measurements employ this principle to calibrate the background noise on the force balance prior to carrying out force measurements."

So eliminate all external forces and you have NO THRUST.

Just maybe EagleWorks did too good a job in the elimination of vibration. GOOD for their Warp Field work but BAD for their EMDrive tests.


Link is here. The claim is in lower half of the thread.
https://www.reddit.com/r/EmDrive/comments/3ah1ta/using_thetravellers_excel_emdrive_calculator/

Thank you :)

Offline VAXHeadroom

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And what the heck, just stack them all up at once. :)


Wow, that's almost too much at once! I needed to stare at it for the longest time to see patterns of relationships. Nice work. Thanks!
Shell

If you can see/think another useful way to try to visualize these I'll see what I can do!  I don't understand really what I'm looking at, just processing the pictures :)  Are these different cross sections (I think they are)? I could build a semi-transparent 3d animated cross section (I think I can anyway!)...
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Offline Rodal

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I just read Mr. Traveller claim on reddit that the vibration increase the thrust of the EmDrive. May I ask you folks if there was already a debate about it here? I would be glad to read about it bit more.

Did anybody here tried to increase the vibration in order to increase thrust? I would be glad to check that as well :).

Quote:

Vibration is everywhere.

Vibratory movement causing small end to big end movement will be opposed by the EMDrive.

Vobratory movement causing Big end to small end movement will be supported by the EMDrive.

Please understand what Roger Shawyer has said:

"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.

UK flight thruster measurements employ this principle to calibrate the background noise on the force balance prior to carrying out force measurements."

So eliminate all external forces and you have NO THRUST.

Just maybe EagleWorks did too good a job in the elimination of vibration. GOOD for their Warp Field work but BAD for their EMDrive tests.


Link is here. The claim is in lower half of the thread.
https://www.reddit.com/r/EmDrive/comments/3ah1ta/using_thetravellers_excel_emdrive_calculator/

Thank you :)
A claim is made based solely on what supposedly Shawyer said.

The magnitude and frequency of the vibration that facilitates the measurement of the EM Drive is never addressed.

Is the EM Drive an equal opportunity friend of all magnitudes and frequencies of vibration?   This is implied, but it leads to absurd nonsense: is nanometer amplitude vibration enough ? How about picometer amplitude vibration?  At what level the boundary between vibration in continuum mechanics and quantum mechanics uncertainty is breached ?

How about frequency?  Is 100 Hz sufficient? How about 0.0000000001 Hz? How about 10^100 Hz?

What is noteworthy is that Shawyer is quoted as " in the UK when the background force changes were eliminated, in an effort to improve force measurement resolution, no EmDrive force was measured" which, if anything, shows that even Shawyer measures no force from the EM Drive when "background forces" are reduced to an unspecified level (for sure Shawyer does not have the ability to have measured picoNewton forces).

The statement is self-contradictory with TT's statement that "Vibration is everywhere."  Yes, vibration, at all kinds of magnitudes is present everywhere, so how was Shawyer then able to measure no force from the EM Drive when "background forces" where reduced to an unspecified level?  Vibrations did not dissappear.

This is the kind of unspecified, unscientific nonsense that makes scientists and engineers to cringe in disbelief.

If anything, the statement

" in the UK when the background force changes were eliminated, in an effort to improve force measurement resolution, no EmDrive force was measured"

means that either the EM Drive is an experimental artifact or if it involves something that can be used for Space Propulsion, Roger Shawyer does not understand what physics are behind it, he doesn't understand how to engineer its development and most clearly he is not able to explain it in scientific and engineering language.

Statements like this serve to explain the controversy surrounding the EM Drive, and why it has made so little progress (despite the extravagant claims) in the 27 years (almost 3 decades) since Shawyer's 1988 patent application.  A scientific approach is needed instead.  Hopefully we will hear more news from NASA soon or get independent experimental data from well-constructed tests from the people in this thread.

« Last Edit: 06/29/2015 12:12 PM by Rodal »

Offline Rodal

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And what the heck, just stack them all up at once. :)


Wow, that's almost too much at once! I needed to stare at it for the longest time to see patterns of relationships. Nice work. Thanks!
Shell

If you can see/think another useful way to try to visualize these I'll see what I can do!  I don't understand really what I'm looking at, just processing the pictures :)  Are these different cross sections (I think they are)? I could build a semi-transparent 3d animated cross section (I think I can anyway!)...

They are cross-sections of a truncated cone.   

The x axis is oriented along the length of the truncated cone.  The y and z axes are perpendicular to each other and both y and z are perpendicular to the x axis.

Fields Em -n  and Hm -n

E= means electric
H= means magnetic

m= means the component of the vector along the m axis

n= means that the field is shown on the plane that has the n axis perpendicular to the plane

Ez - x

Means:

Electric field
vector component along z axis
shown on the plane cross-section that has x perpendicular to the plane (the cross-section plane that is defined by the y and z axes)

///////////////////

If you could construct 3D plots out of this information, that would be great.
The numerical data from which the plots were made should be available from aero, as all plots are constructed from numerical data.
« Last Edit: 06/29/2015 11:31 AM by Rodal »

Offline Rodal

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I think the traveller will like this article when he feels better:

Direct determination of the resonance properties of metallic conical nanoantennas

http://www.researchgate.net/profile/Carlo_Liberale/publication/260040081_Direct_determination
_of_the_resonance_properties_of_metallic_conical_nanoantennas/links/5476ccbd0cf2778985b08312.pdf

"A cone can be envisioned as a continuous sequence of coaxial cylinders with decreasing radii. Under the local
mode concept, valid for slowly varying structures [21], within local domains the plasmonic cylinder modes are
good approximations to the solutions of the Maxwell’s equations."


The claim was made by TT that modeling the truncated cone as a number of coaxial cylinders of decreasing radii leads to natural frequencies and mode shapes that are different and superior to those obtained from Finite Element and exact solutions. 

This reference rather than confirming that nonsensical claim, it denies it.  On the contrary, the authors of this paper make it clear that they offer this procedure only as an approximation, that, under certain conditions, it may be good enough, and be simpler than the (accepted by the authors) accurate exact solution or the solution obtained by superior numerical methods (like the Finite Element Method).   

So: if TT obtains with his numerical procedure something that is close to the exact solution, good for him.  If he obtains a different frequency or mode shape from the exact solution, then his approximation is clearly the source of the discrepancy, as it is clearly stated by the authors of this paper.


__________
(*) This approximate method of analyzing a cone as a number of coaxial cylinders of different radii has been known for a very, very long time.  It originated much before the invention of the Finite Element method.  It has appeared in patents and publications much earlier.  It looks like the authors of this paper re-discovered this method and that the journals referees are unaware of such prior literature. The paper was published in Optics Letters, a journal whose emphasis is rapid communication of short letters, and whose review centers on whether the articles are presented in a clear manner:  see the standards of review here https://www.osapublishing.org/journal/ol/pdfs/OL-ReviewCriteria.pdf
« Last Edit: 06/29/2015 12:26 PM by Rodal »

Offline OttO

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It seem to me that there is more to a frustum that we can thought:
(OK these are way up my head and now I remember why I stopped math  :P)


Vacuum energy in conical space with additional boundary conditions
http://arxiv.org/abs/1003.0886
It is only for a cylinder but who knows


Fermionic current densities induced by magnetic flux in a conical space with a circular boundary
http://arxiv.org/abs/1008.1743


Offline Chrochne

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I just read Mr. Traveller claim on reddit that the vibration increase the thrust of the EmDrive. May I ask you folks if there was already a debate about it here? I would be glad to read about it bit more.

Did anybody here tried to increase the vibration in order to increase thrust? I would be glad to check that as well :).

Quote:

Vibration is everywhere.

Vibratory movement causing small end to big end movement will be opposed by the EMDrive.

Vobratory movement causing Big end to small end movement will be supported by the EMDrive.

Please understand what Roger Shawyer has said:

"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.

UK flight thruster measurements employ this principle to calibrate the background noise on the force balance prior to carrying out force measurements."

So eliminate all external forces and you have NO THRUST.

Just maybe EagleWorks did too good a job in the elimination of vibration. GOOD for their Warp Field work but BAD for their EMDrive tests.


Link is here. The claim is in lower half of the thread.
https://www.reddit.com/r/EmDrive/comments/3ah1ta/using_thetravellers_excel_emdrive_calculator/

Thank you :)
A claim is made based solely on what supposedly Shawyer said.

The magnitude and frequency of the vibration that facilitates the measurement of the EM Drive is never addressed.

Is the EM Drive an equal opportunity friend of all magnitudes and frequencies of vibration?   This is implied, but it leads to absurd nonsense: is nanometer amplitude vibration enough ? How about picometer amplitude vibration?  At what level the boundary between vibration in continuum mechanics and quantum mechanics uncertainty is breached ?

How about frequency?  Is 100 Hz sufficient? How about 0.0000000001 Hz? How about 10^100 Hz?

What is noteworthy is that Shawyer is quoted as " in the UK when the background force changes were eliminated, in an effort to improve force measurement resolution, no EmDrive force was measured" which, if anything, shows that even Shawyer measures no force from the EM Drive when "background forces" are reduced to an unspecified level (for sure Shawyer does not have the ability to have measured picoNewton forces).

The statement is self-contradictory with TT's statement that "Vibration is everywhere."  Yes, vibration, at all kinds of magnitudes is present everywhere, so how was Shawyer then able to measure no force from the EM Drive when "background forces" where reduced to an unspecified level?  Vibrations did not dissappear.

This is the kind of unspecified, unscientific nonsense that makes scientists and engineers to cringe in disbelief.

If anything, the statement

" in the UK when the background force changes were eliminated, in an effort to improve force measurement resolution, no EmDrive force was measured"

means that either the EM Drive is an experimental artifact or if it involves something that can be used for Space Propulsion, Roger Shawyer does not understand what physics are behind it, he doesn't understand how to engineer its development and most clearly he is not able to explain it in scientific and engineering language.

Statements like this serve to explain the controversy surrounding the EM Drive, and why it has made so little progress (despite the extravagant claims) in the 27 years (almost 3 decades) since Shawyer's 1988 patent application.  A scientific approach is needed instead.  Hopefully we will hear more news from NASA soon or get independent experimental data from well-constructed tests from the people in this thread.

Thank you for your answer Dr. Rodal. It is much more clear now. I guess my enthusiasm comes from my wish that it works :). If by some miracle this works, It might help to reduce some of the conflicts over the resources in the world, thus make the world more peaceful (from realistic point of view - sorry MA in International Relations :-P just cant help to see where this can help). But I understand of course that to wish does not exactly help. Yes, best chance is now NASA and less "super" claims.

Offline Rodal

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... I estimate (but I maybe wrong) that TM114's frequency is 0.8% higher than TE013, TE114 is 3.9% higher frequency,  TM212 is 6.5% lower and TE213 is 9.2% lower. frequency.
Using those estimates, Meep should have picked up TM114 (except I was exciting TE modes)  and maybe TE114. Probably not TM212 or TE213. I guess we'll see in the fields, if someone can get some numbers somehow....

1) For 10.2 inches you should place the antenna to excite an electric excitation, because the resonance is transverse electric mode shape TE013 at 2.45GHz with L=10.2 inches.  When you state that TM114 would be excited instead of TE013, does that mean that you placed the antenna to excite a magnetic instead of electric mode ?  :)  .


2) Some time ago you were able to calculate with Meep the net force on the EM Drive. It would be most interesting if you could calculate the net force on the EM Drive at every finite difference time step for the cases of rfmwguy being studied, so that we can plot the force vs. time, and see what its time behavior looks like.

There are indications in your plots that the force may not be a sine curve with time, and therefore that the force may sum up to a net amount over an integer number of periods, but we need numerical confirmation (or denial) of this.
« Last Edit: 06/29/2015 12:55 PM by Rodal »

Offline rfmwguy

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...

Sorry to hear that, rfmwguy.

I'm awaiting to see if I will soon be in the same boat with the stuff I ordered as well.

I don't know when I'll learn that you can't afford to go cheap. ;)
Funny thing is the cheapest module caused the problem. No big deal, 2.4ghz stuff is in every store and easy to obtain which is a big plus. Let u know what I substitute in there...probably a teardown of a wifi cam. Most all are 100mw.

I know how you feel, but I just found out that the surface resistance of copper at 2.4GHz is supposedly,

RS = 0.013 Ohms.

From this, you can get the power losses as the integral over the internal surface area,

P_loss = ∮S(RS*|H|2)*dS, Basically Ohm's law.

That's a pretty high resistance, so a 100mW source will hardly overcome the copper losses. Based on the heating reported, the losses are in the "watts" range at high Q. I'm sure you will need a stronger source.
Todd
Thanks, it will be 8W final, but issue is still the same. One difference is I chose copper mesh, limited surface area, limited losses. Also, chose mesh to allow air in/out to avoid ballooning and permit smoke testing. Wanted to see if it generated air currents, probably afraid of it being a simple ion blaster.

However, after my annoyance this weekend with the junk exciter, I realized the frustum exoskeleton would easily adapt to mounting a magnetron on it. With the 12" cube, I could add an exterior wall, making it a faraday cage. This could overcome any safety issues I had. We'll see...

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