Quote from: Rodal on 08/04/2015 02:49 pmA gas is a compressible fluid and as such describable by fluid dynamics, just a different constitutive law. Different fluids have different constitutive laws.True.What this video shows is light waves consisting of photons traveling as waves down a long conical fiber optic cable (right to left) that causes them to frequency shift as they loose resonance and then decay into traveling evanescent waves outside of the fiber optic walls. These evanescent waves carry momentum and spin components that are orthogonal to the direction of wave propagation. Those components of momentum and spin outside of the walls of the fiber optic cable effect the fluid inducing movement along the length of the optic cable.I have a conical frustum analogous to the tapered fiber optic that induces the same actions in the frustum. The collapsing modes and waves decay into evanescents just like the fiber optic. My question would be what happens to that spin and momentum of that high Q wave as it collapses into the end or sidewalls of the cavity? Mediums are different but it's still photons and waves.
A gas is a compressible fluid and as such describable by fluid dynamics, just a different constitutive law. Different fluids have different constitutive laws.
Quote from: TheTraveller on 08/04/2015 04:40 pmQuote from: Rodal on 08/04/2015 04:30 pm I won't waste my time in calculating the exact number based on your definition of length since from your answer it is evident that you don't care, and I have better things to do.If I didn't care I would not have taken the time to explain what length means to frustum resonance.My resonance, at TE013, for the Mark 2 frustum design as below is 2.45GHz and not 3.9GHz. I deleted the post with the calculations since they were based on an incorrect length. I wish I could take the time back that I wasted in those calculations and posting them. Good luck with your design at whatever frequency you decide to make it (at one point 3.9Ghz then it was 2.45GHz, then it was 1.9Ghz because of BlueTooth and now is back to 2.45 GHz ?, it doesn't matter to me )
Quote from: Rodal on 08/04/2015 04:30 pm I won't waste my time in calculating the exact number based on your definition of length since from your answer it is evident that you don't care, and I have better things to do.If I didn't care I would not have taken the time to explain what length means to frustum resonance.My resonance, at TE013, for the Mark 2 frustum design as below is 2.45GHz and not 3.9GHz.
I won't waste my time in calculating the exact number based on your definition of length since from your answer it is evident that you don't care, and I have better things to do.
Note to experimentalists:For safety, run an EM detector around the outside of your emdrive while its powered up. Either through shoddy construction(likely) or some as yet unknown (to me) phenomenon, my resonator is leaking radiation from the small end. Based on the fall-off as a function of distance I believe it is evanescent. I have spectrum analyzer on order; when it arrives I'll have a better idea of what it is.<lurk />
Quote from: SeeShells on 08/04/2015 03:17 pmQuote from: Rodal on 08/04/2015 02:49 pmA gas is a compressible fluid and as such describable by fluid dynamics, just a different constitutive law. Different fluids have different constitutive laws.True.What this video shows is light waves consisting of photons traveling as waves down a long conical fiber optic cable (right to left) that causes them to frequency shift as they loose resonance and then decay into traveling evanescent waves outside of the fiber optic walls. These evanescent waves carry momentum and spin components that are orthogonal to the direction of wave propagation. Those components of momentum and spin outside of the walls of the fiber optic cable effect the fluid inducing movement along the length of the optic cable.I have a conical frustum analogous to the tapered fiber optic that induces the same actions in the frustum. The collapsing modes and waves decay into evanescents just like the fiber optic. My question would be what happens to that spin and momentum of that high Q wave as it collapses into the end or sidewalls of the cavity? Mediums are different but it's still photons and waves. Oh - So if you bundle a bunch of them together and run them in air at the right frequency, then the evanescent waves will push the air molecules along - toward which end? And if you run them in vacuum they will push the photons along?
Quote from: ElizabethGreene on 08/04/2015 05:10 pmNote to experimentalists:For safety, run an EM detector around the outside of your emdrive while its powered up. Either through shoddy construction(likely) or some as yet unknown (to me) phenomenon, my resonator is leaking radiation from the small end. Based on the fall-off as a function of distance I believe it is evanescent. I have spectrum analyzer on order; when it arrives I'll have a better idea of what it is.<lurk />Good advise.Please share your dimensions, frequency and excitation mode as then I'll run a set of number for you.How do you know you have resonance?Are you using a magnetron or narrow band Rf amp?What wattage?Thanks for your reply and good luck.
All I ask is for you to be safe. If you would like I'll fed-ex my little USB SA overnight as long as you return it when you get yours.Shell
Inexpensive Microwave Leakage Detectors - Are They Worth It? (A Performance Evaluation Report)Journal of Microwave Power and Electromagnetic Energy, 46 (3), 2012, pp. 128-138.
Quote from: ElizabethGreene on 08/04/2015 05:10 pmNote to experimentalists:For safety, run an EM detector around the outside of your emdrive while its powered up. Either through shoddy construction(likely) or some as yet unknown (to me) phenomenon, my resonator is leaking radiation from the small end. Based on the fall-off as a function of distance I believe it is evanescent. I have spectrum analyzer on order; when it arrives I'll have a better idea of what it is.<lurk />Elizabeth, this is very important news, as many of us have suspected that the EM Drive is NOT a closed system and that "thrust" may be explainable by what is leaking.Looking forward to what you measure
Thanks, I think I've narrowed down the theory candidates over the past week. Plotting what would be the phase velocity in what I posted above, it appears there is a significant boost in thrust-to-power ratio if we allow the small end to be much smaller than the big end, like 1/10th the size. Basically, thrust depends almost entirely on the side wall force, not the small end. We want to maximize force on the walls, like @Rodal's plot below. It also seems, operating at around 100MHz, is not an unmanageable model either.Todd
Quote from: rfmwguy on 08/04/2015 03:12 pmThermal tests done including 5 minute run at 30% power, which is what I'll use for fulcrum test. What I learned: Matching into frustum is good, magnetron ran at temperatures well below 200°C. Still had minor arcing, corrected it with full teardown and replacement of Db with mesh only, no copper clad. IOW, frustum is now all mesh except for Ds where magnetron is mounted. There was no arcing on Ds throughout any thermal testing. Plasma focused on Db, interestingly enough diagonally across from radome, not directly across axially.Here's the video, time to do yard work, oh joy:Looks good.One thing that bothered me was the rapid changes in temperature measured by the IR thermometer when the magnetron was running. Could there be interference causing issues with the thermometer? As you said, "It's not an accurate way to measure the temperature."Get a good old fashioned mechanical grill thermometer and mount it directly to the heat sink. Here's a link to one I found to show what I'm talking about.http://www.centralrestaurant.com/Grill-Thermometer---2-in-Dial-Stainless-Steel-c177p12987.html?st-t=google_shopping&vt-k=&vt-pti=98375234695&gclid=CLfKp_Xgj8cCFUMjgQodAZoAKAYou may want to look around for what you need. That's just the first one I found doing a search.Take a look at the dial, it's NSF certified!
Thermal tests done including 5 minute run at 30% power, which is what I'll use for fulcrum test. What I learned: Matching into frustum is good, magnetron ran at temperatures well below 200°C. Still had minor arcing, corrected it with full teardown and replacement of Db with mesh only, no copper clad. IOW, frustum is now all mesh except for Ds where magnetron is mounted. There was no arcing on Ds throughout any thermal testing. Plasma focused on Db, interestingly enough diagonally across from radome, not directly across axially.Here's the video, time to do yard work, oh joy:
Quote from: ElizabethGreene on 08/04/2015 05:10 pmNote to experimentalists:For safety, run an EM detector around the outside of your emdrive while its powered up. Either through shoddy construction(likely) or some as yet unknown (to me) phenomenon, my resonator is leaking radiation from the small end. Based on the fall-off as a function of distance I believe it is evanescent. I have spectrum analyzer on order; when it arrives I'll have a better idea of what it is.<lurk />You can use copper adhesive tape to easy fix any leakage http://www.iccfl.com/index.php?cPath=135_184&osCsid=ur8g03ipgtkkdh6src34otdh84
... SPR in-house software and produced the Df and resonant frequency at TE013 being:Frustum big diameter m: 0.2314m (my data)Frustum small diameter: 0.1257m (my data)Frustum centre length: 0.1386m (my data)Mode: TE013 (my data)Resonance: 3.9003 GHz (SPR data based on the above)Df: 0.634 (SPR data based on the above)...
...BTW what resonance and Q do you get for my Flight Thruster estimated dimensions?...
How is thrust greater than a photon rocket explained by leaking photons? Todd