Perhaps someone can imagine an effective approximation.
Quote from: zellerium on 03/10/2016 03:50 pmI 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 intop radius 1.4 inbottom radius 4.4 inwaveguide input should be at center, not 1/4 lengthAlso, 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.
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 intop radius 1.4 inbottom radius 4.4 inwaveguide input should be at center, not 1/4 lengthAlso, 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?
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
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.
Quote from: rfmwguy on 03/10/2016 02:35 pmI'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 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.
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 ?
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.
Quote from: RFPlumber on 03/10/2016 08:55 pmHere’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.
Here’s a story about having tried to publish a paper....
Quote from: rq3 on 03/10/2016 07:07 pmQuote from: rfmwguy on 03/10/2016 02:35 pmI'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 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?
What happened to that project ?
Very nice, can you estimate the real value of 0.1 distortion in mm?
(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.
