Author Topic: EM Drive Developments - related to space flight applications - Thread 7  (Read 1663323 times)

Offline Monomorphic

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Perhaps someone can imagine an effective approximation.

I'm pretty sure I can do this in FEKO if I import the misaligned meshes from another program, and then crank up the near field point requests.

How much shall I make the end plates misaligned?  I'm going to try 5 degrees off on the small end plate first.
« Last Edit: 03/10/2016 04:33 pm by Monomorphic »

Offline SeeShells

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I designed a frustum that should be able to be made within at least .001 in on an auto lathe. Attached is the drawing for the TE113 mode.
Unfortunately this method get much more pricey for a larger frustum because its turned from a solid piece of Al, but a 9 inch diameter 9 inch tall slug of 6061 should run ~$500 to $600.
 
A few updates I haven't made to these drawings since latest sims:
Aperture size: .875 in by 1.005 in
top radius 1.4 in
bottom radius 4.4 in
waveguide input should be at center, not 1/4 length

Also, I haven't really figured out how to secure the waveguide without welding it in case it needs to be replaced. Anyone have a simple solution?
Fantastic dwgs! THIS is what I've been looking for and most familiar visual with from back in the day. Guess I've gotta get a student version somehow  ;)

Waveguide launch into the side is quite challenging. Shell might have the answer. Consider this: direct injection of magnetron monopole requires 1 hole and an adapter ring that can be pressure fitted. A 4 point frame would be needed to mount magnetron assembly.

Think it might be easier than a waveguide weld.

If you want to take it apart then a 3/8" or 1/4" mounting plate onto the sidewall of the frustum can be done. Secure it with waveguide weld and mount and slide the waveguide over it and secure it with small screws. Detail work but it can be done and made RF tight.

I liked 1/4 inch Aluminum because it can be hand formed over a mandrel and I used a large hammer and a steel pipe to get it curved.

Shell

Added: Use your fingers.
https://www.sciencedaily.com/releases/2013/09/130916110853.htm
« Last Edit: 03/10/2016 05:09 pm by SeeShells »

Offline X_RaY

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@TT
Tolerances of 13µm for a 2.45GHz frustum made of copper???
This would be hard to build and for sure really expensive ;)
Another problem is the thermal expansion coefficient over a few Kelvin is bigger than this!

Example:
L=0,25m (Frustum sidewall length)
a=16.5e-6*Ke-1 (thermal lenght expansion coefficient of copper)
dK=50 degree (temperatur difference)

--->dL=206.25µm

https://forum.nasaspaceflight.com/index.php?topic=39214.msg1470152#msg1470152
https://de.wikipedia.org/wiki/Ausdehnungskoeffizient / https://en.wikipedia.org/wiki/Thermal_expansion

« Last Edit: 03/10/2016 07:05 pm by X_RaY »

Offline Monomorphic

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Pardon the large image, but I think it shows relevant information regarding frustum tolerances. The interesting thing here is Random Distortion (0.1) actually has a higher near field power. However, I do not think that is because the distortion makes it more efficient, but that I am not quite center-on TE311, but a little off - and the dimensions of the slightly distorted frustum are closer to center-on TE311.

Offline rq3

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I've learned a lot about metal working the past couple of weeks, regarding flatness. If it looks flat...it really isn't.

The 1/8 copper disk (small diameter) looked great from the supplier until I put it on a lapping plate with a backing disk. Progressing from 60 to 2000 grit sandpaper, I was amazed at the material I had to remove to make it close to "flat".

At 2000 grit last night, serious striations are gone but there is still a micron level "unflatness" even after about 4 hours of hand sanding. What this taught me is there is almost no way DIYers can ever achieve perfection in sidewalls. I agree its desirable to maintain shape and symmetry, but I think its best not to worry about it too much. A fully machined and polished frustum is well beyond our budgets. I received a quote for leveling and polishing the small endplate and it was $675  :o

A few threads ago I suggested that electroforming might be the best frustum fabrication technique, and I still think so. Complex wavequide structures are often fabbed this way, and beauty of it is that the final interior finish depends only on the finish of the exterior surface of the form.

The ideal form would be conductive machinable wax, and the plating process is easily a DIY process (jewelers do it quite often in lieu of lost wax casting).

The final frustum would be a reflection (pun intended) of the form, with surface finishes of 2 micron regularly achievable. The wax form would be easily turned on a lathe, and the surface polished by flame or solvent, much like applying a "french polish" to a wooden item in the lathe.

Offline rfmwguy

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Pardon the large image, but I think it shows relevant information regarding frustum tolerances. The interesting thing here is Random Distortion (0.1) actually has a higher near field power. However, I do not think that is because the distortion makes it more efficient, but that I am not quite center-on TE311, but a little off - and the dimensions of the slightly distorted frustum are closer to center-on TE311.
Very nice, can you estimate the real value of 0.1 distortion in mm?

Offline madsci

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  Monomorphic,

  If I'm not mistaken you were working on an optical EmDrive:

   https://www.reddit.com/r/EmDrive/comments/3p1atx/optical_em_drive/

  What happened to that project ?

Offline rfmwguy

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I've learned a lot about metal working the past couple of weeks, regarding flatness. If it looks flat...it really isn't.

The 1/8 copper disk (small diameter) looked great from the supplier until I put it on a lapping plate with a backing disk. Progressing from 60 to 2000 grit sandpaper, I was amazed at the material I had to remove to make it close to "flat".

At 2000 grit last night, serious striations are gone but there is still a micron level "unflatness" even after about 4 hours of hand sanding. What this taught me is there is almost no way DIYers can ever achieve perfection in sidewalls. I agree its desirable to maintain shape and symmetry, but I think its best not to worry about it too much. A fully machined and polished frustum is well beyond our budgets. I received a quote for leveling and polishing the small endplate and it was $675  :o

A few threads ago I suggested that electroforming might be the best frustum fabrication technique, and I still think so. Complex wavequide structures are often fabbed this way, and beauty of it is that the final interior finish depends only on the finish of the exterior surface of the form.

The ideal form would be conductive machinable wax, and the plating process is easily a DIY process (jewelers do it quite often in lieu of lost wax casting).

The final frustum would be a reflection (pun intended) of the form, with surface finishes of 2 micron regularly achievable. The wax form would be easily turned on a lathe, and the surface polished by flame or solvent, much like applying a "french polish" to a wooden item in the lathe.
This is still interesting to me. Do you have any idea what amount of time it would take to deposit 2 mm of copper on a typical frustum dimension?

Offline Rodal

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  Monomorphic,

  If I'm not mistaken you were working on an optical EmDrive:

   https://www.reddit.com/r/EmDrive/comments/3p1atx/optical_em_drive/

  What happened to that project ?
The wavelength is much smaller in the optical range and the force predicted by all EM Drive theories should be much, much smaller in the optical range with a small micro-dimensioned  EM Drive.

See:

https://forum.nasaspaceflight.com/index.php?topic=39214.msg1474347#msg1474347


Conversely if instead of using an EM Drive with very small micro dimensions, the plan was to use an EM Drive with dimensions similar to the ones built up to now, the mode shape would be extremely high at optical frequencies, and such very high modes are small amplitude. A FEKO simulation would show this.
« Last Edit: 03/10/2016 08:58 pm by Rodal »

Offline RFPlumber

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Here’s a story about having tried to publish a paper. The paper describing my null result experiment is now available on Vixra (http://viXra.org/abs/1603.0153). I made a good faith effort to publish it on arXiv.org first, I was even moderately optimistic in the beginning when I knew mostly nothing about the nature of this “wonderful” organization and was still assuming that all it takes to publish there was a single endorsement… Turns out both ArchiveFreedom.org and Vixra.org exist for a good reason. And no, it is not the endorsement step at arXiv which is a concern. It is what happens once the paper has been endorsed and submitted…

…In my case it was reasonably easy to get endorsements; I searched their popular physics category for papers which would be at least marginally related to EmDrive, such as space travel, warp drive, etc. and contacted those authors who had the endorsement privilege. Initially no one replied, but after a week or so I received a notification that I had been endorsed and could now submit my paper. And then a few days later I received another endorsement notification, and then one more. My interpretation of this is that I have been endorsed by at least 3 people. Eventually about 2 weeks later I received a reply from one of my endorsers who happened to be a Professor of Physics at a certain university in California, acknowledging that he has read my paper and found it “interesting and well written". Looking back this has been the high point of this entire publishing effort.  :)
 
Encouraged by all those endorsements I submitted to arXiv. The paper was accepted but then promptly put on hold just 3 hour before going live…  A week later I received a notice from their (anonymous) moderation team asking that before I attempt any future submissions (note the scope here – it is not just for this paper, but for all future submissions of mine) to provide them with a list of my conventional publications and to further clarify my institutional affiliation. And this is where it just struck me, as presumably they consider this information somehow relevant to their decision on whether a particular  paper gets published or not. Well… to me this is just wrong, but it’s their effort, and so I honestly told them that I didn’t have any conventional publications except for 10 or so US patents, and those were all in Computer Science anyway. Ten days later I finally received another e-mail informing me that my submission was removed for lack of having a conventional publication record. Btw, that last e-mail didn’t even have a “sorry to inform you” anywhere in it.

This was definitely an eye-opening experience, and I have got my own strong opinion about this place. Also I do feel for those professional scientists who might depend on it for their careers.

The paper has then been published on Vixra along with a donation to help them keep going. I will update the link on EmDrive Wiki to point to this published version.

The “Acknowledgments” paragraph  in the paper reads:
“The author would like to thank the participants of the “EMDrive Developments” forum at www.nasaspaceflight.com for their constructive and timely feedback while conducting this experiment.”

This concludes the saga.

Offline Rodal

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Here’s a story about having tried to publish a paper. The paper describing my null result experiment is now available on Vixra (http://viXra.org/abs/1603.0153). I made a good faith effort to publish it on arXiv.org first, I was even moderately optimistic in the beginning when I knew mostly nothing about the nature of this “wonderful” organization and was still assuming that all it takes to publish there was a single endorsement… Turns out both ArchiveFreedom.org and Vixra.org exist for a good reason. And no, it is not the endorsement step at arXiv which is a concern. It is what happens once the paper has been endorsed and submitted…

…In my case it was reasonably easy to get endorsements; I searched their popular physics category for papers which would be at least marginally related to EmDrive, such as space travel, warp drive, etc. and contacted those authors who had the endorsement privilege. Initially no one replied, but after a week or so I received a notification that I had been endorsed and could now submit my paper. And then a few days later I received another endorsement notification, and then one more. My interpretation of this is that I have been endorsed by at least 3 people. Eventually about 2 weeks later I received a reply from one of my endorsers who happened to be a Professor of Physics at a certain university in California, acknowledging that he has read my paper and found it “interesting and well written". Looking back this has been the high point of this entire publishing effort.  :)
 
Encouraged by all those endorsements I submitted to arXiv. The paper was accepted but then promptly put on hold just 3 hour before going live…  A week later I received a notice from their (anonymous) moderation team asking that before I attempt any future submissions (note the scope here – it is not just for this paper, but for all future submissions of mine) to provide them with a list of my conventional publications and to further clarify my institutional affiliation. And this is where it just struck me, as presumably they consider this information somehow relevant to their decision on whether a particular  paper gets published or not. Well… to me this is just wrong, but it’s their effort, and so I honestly told them that I didn’t have any conventional publications except for 10 or so US patents, and those were all in Computer Science anyway. Ten days later I finally received another e-mail informing me that my submission was removed for lack of having a conventional publication record. Btw, that last e-mail didn’t even have a “sorry to inform you” anywhere in it.

This was definitely an eye-opening experience, and I have got my own strong opinion about this place. Also I do feel for those professional scientists who might depend on it for their careers.

The paper has then been published on Vixra along with a donation to help them keep going. I will update the link on EmDrive Wiki to point to this published version.

The “Acknowledgments” paragraph  in the paper reads:
“The author would like to thank the participants of the “EMDrive Developments” forum at www.nasaspaceflight.com for their constructive and timely feedback while conducting this experiment.”

This concludes the saga.

Congratulations again on your excellent test program !

You exhibited the true hallmark of scientific experimentation: a complete lack of bias and reporting the actual results without prejudice.
« Last Edit: 03/10/2016 09:05 pm by Rodal »

Offline RFPlumber

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Here’s a story about having tried to publish a paper.
...

Congratulations again on your excellent test program !

You exhibited the true hallmark of scientific experimentation: a complete lack of bias and reporting the actual results without prejudice.

Thank you. I honestly wish for there would have been some anomalous force there... At this point I don't think there's any though.

Offline Rodal

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Pardon the large image, but I think it shows relevant information regarding frustum tolerances. The interesting thing here is Random Distortion (0.1) actually has a higher near field power. However, I do not think that is because the distortion makes it more efficient, but that I am not quite center-on TE311, but a little off - and the dimensions of the slightly distorted frustum are closer to center-on TE311.

Can you please also show:

1) a comparison of theoretical Q (quality of resonance) for the cases shown above

2) comparison: A) random distortion only on the end plates vs.B)  random distortion only on the side conical walls

Offline rq3

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I've learned a lot about metal working the past couple of weeks, regarding flatness. If it looks flat...it really isn't.

The 1/8 copper disk (small diameter) looked great from the supplier until I put it on a lapping plate with a backing disk. Progressing from 60 to 2000 grit sandpaper, I was amazed at the material I had to remove to make it close to "flat".

At 2000 grit last night, serious striations are gone but there is still a micron level "unflatness" even after about 4 hours of hand sanding. What this taught me is there is almost no way DIYers can ever achieve perfection in sidewalls. I agree its desirable to maintain shape and symmetry, but I think its best not to worry about it too much. A fully machined and polished frustum is well beyond our budgets. I received a quote for leveling and polishing the small endplate and it was $675  :o

A few threads ago I suggested that electroforming might be the best frustum fabrication technique, and I still think so. Complex wavequide structures are often fabbed this way, and beauty of it is that the final interior finish depends only on the finish of the exterior surface of the form.

The ideal form would be conductive machinable wax, and the plating process is easily a DIY process (jewelers do it quite often in lieu of lost wax casting).

The final frustum would be a reflection (pun intended) of the form, with surface finishes of 2 micron regularly achievable. The wax form would be easily turned on a lathe, and the surface polished by flame or solvent, much like applying a "french polish" to a wooden item in the lathe.
This is still interesting to me. Do you have any idea what amount of time it would take to deposit 2 mm of copper on a typical frustum dimension?

My own experience with electroforming is that, in general, the lower the current the smoother the finish and of course the slower the deposit. A guesstimate for the "average" frustum would be on the order of 24-48 hours for 2 mm thick walls with 2 micron surface finish. Under tightly controlled conditions, quite a bit faster (perhaps 4-6 hours).

Offline Monomorphic

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  What happened to that project ?

Why build one when you can have two at twice the price? I'm still working on the optical/laser emdrive. Plan on using the same interferometer test rig for both 2.45Ghz and 450nm versions. I'm slowly building/purchasing all the myriad parts for the optical version. The optical version is much more tedious and costly. It all adds up fast and I can only sneak so much $$$ past the spouse each month!

Offline Monomorphic

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Very nice, can you estimate the real value of 0.1 distortion in mm?

It looks like between 1 and 2 mm. Closer to 2.
« Last Edit: 03/10/2016 09:57 pm by Monomorphic »

Offline rfmwguy

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(snip)
The “Acknowledgments” paragraph  in the paper reads:
“The author would like to thank the participants of the “EMDrive Developments” forum at www.nasaspaceflight.com for their constructive and timely feedback while conducting this experiment.”

This concludes the saga.
Thanks so much for sharing. Similar story of my own in the conventional book publishing biz. My "adhd" has had me writing family genealogies, fiction and non-fiction books over the past 20 years; that in addition to trade mag publications in electronics...

I sent my first book years ago to several publishers who asked similar things of me...provenance and name recognition is paramount to these "big" publishers. You get around this by ordering advance copies of your own book from them and then peddle it yourself. The system is designed to keep newbies out without "paying" their dues up front so to speak.

Then print on demand happened and so much for the old-school roadblock. They books did reasonably well and I even received offers from publishers afterwards once my amazon numbers started rising. By then, I was off doing something else (making a documentary about one of the books) and had no interest in pursuing book advances or cranking out volumes of literature (helped of course by the ever-present army of ghost writers contracted by the publishers).

Bottom line is, I would have done the same thing you did on your paper...break down the firewall and find other outlets. We have that option nowadays that many an aspiring author didn't have a couple of decades ago. So be it.

Thanks for the story and for our mention in your paper. While you may not have experienced success on your test, you learned a lot and have the satisfaction that the gauntlet can be overcome. Great success story and congrats on your paper. Perhaps we'll hear more from you down the road if you decide to dust off the test gear.

Offline FattyLumpkin

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Seems a shame to put so much time, effort and $$ into these prototypes without providing some protection for the (Q)-quality of the inner surfaces. Any one for evacuating the frustum of air and replacing it with nitrogen? + one could +/- calculate volume changes associated with predicted thermal expansion and pressurize the frustum at X value < ambient in order to mitigate the "balloon effect". Of course thermal expansion of the construction materials: copper, aluminum, silver et al would still be in the running, but oxidation of the surfaces would ostensibly be eliminated.   F L

Offline FattyLumpkin

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The above attached horn is electroformed and gold plated $895.   About  4"L x 2.39" D.  K band

Offline OttO

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Hi, I do not know if it is useful but to have a good surface quality I think that copper plated glass would be useful for a DIYer. For example a google search for copper plated martini glass is interesting. Frustum for less than 10$ :-)
The copper would be at the exterior of the glass but that would be interesting to weld it to the mirror plates at each end...

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