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#1060
by
Monomorphic
on 08 Apr, 2016 12:59
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Monomorphic, I calculated a frequency of ****6.9122-6.9196 GHz**** to run in the Cubesat frustum (not 2.45). 
I had no idea you were going to perform a sim on it. Perhaps you can try the above mentioned frequency(s). If I did the math correctly it should look quite good (a scaled down version of NASA's TM212, 91.2 micro-Newton model). Thanks for your time! 
, FL
The sim was run at 6.9122Ghz. Side wall injection, dipole antenna.
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#1061
by
Rodal
on 08 Apr, 2016 13:13
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Monomorphic, I calculated a frequency of ****6.9122-6.9196 GHz**** to run in the Cubesat frustum (not 2.45). I had no idea you were going to perform a sim on it. Perhaps you can try the above mentioned frequency(s). If I did the math correctly it should look quite good (a scaled down version of NASA's TM212, 91.2 micro-Newton model). Thanks for your time! , FL
The sim was run at 6.9122Ghz. Side wall injection, dipole antenna.
It should be emphasized that the mode shape shown by Monomorphic's FEKO calculation is
not TM 212
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#1062
by
Monomorphic
on 08 Apr, 2016 13:40
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Here is a sim using NASA's dimensions at 2.4575Ghz for TM212. Notice how nicely FEKO agrees with COMSOL.
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#1063
by
Rodal
on 08 Apr, 2016 13:53
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Here is a sim using NASA's dimensions at 2.4575Ghz for TM212. Notice how nicely FEKO agrees with COMSOL.
In previous threads I showed that the exact solution agreed with NASA's COMSOL's results. Since FEKO agrees with NASA's COMSOL's results, it follows that Monomorphic FEKO's results agree with the exact solution.
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#1064
by
X_RaY
on 08 Apr, 2016 19:17
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Here is a sim using NASA's dimensions at 2.4575Ghz for TM212. Notice how nicely FEKO agrees with COMSOL.
In previous threads I showed that the exact solution agreed with NASA's COMSOL's results. Since FEKO agrees with NASA's COMSOL's results, it follows that Monomorphic FEKO's results agree with the exact solution.
I would be surprised if the results of numerical field calculation programs would vary since all of them solve the Maxwell equations.
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#1065
by
Rodal
on 08 Apr, 2016 20:02
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Here is a sim using NASA's dimensions at 2.4575Ghz for TM212. Notice how nicely FEKO agrees with COMSOL.
In previous threads I showed that the exact solution agreed with NASA's COMSOL's results. Since FEKO agrees with NASA's COMSOL's results, it follows that Monomorphic FEKO's results agree with the exact solution.
I would be surprised if the results of numerical field calculation programs would vary since all of them solve the Maxwell equations.
1) TheTraveller posted in the past that natural frequencies (using his Excel spreadsheet) that are different than those calculated by NASA using COMSOL Finite Element analysis. There are a number of cases, most particularly TE012 mode shape without a dielectric insert, for example. Thus it is re-assuring (but I agree with you not unexpected) that the COMSOL, FEKO and exact solutions agree. When the spreadsheet method used by TheTraveller disagrees, it has to do with the approximations used by TheTraveller in his spreadsheet method. (This is not to disparage his spreadsheet method, since as I said, such spreadsheet methods have a very useful role to play in preliminary design, plus the fact that TheTraveller's spreadsheet is free as opposed to the cost of COMSOL or FEKO licenses).
2) I don't recall seeing a calculation from MEEP in these EM Drive threads that closely matches NASA's COMSOL calculations.
3) While in principle all these methods solve Maxwell's equations, they are numerical methods that rely on a mesh to converge to the correct solution. Usually analysts in these threads do not conduct a convergence study so there is always the question whether the mesh is refined enough to converge to the correct solution. In that sense the question is not whether COMSOL or FEKO can solve Maxwell's equations correctly, but whether the analyst's model is correct. It is therefore comforting that the posted solutions using COMSOL finite element analysis and FEKO's boundary element method are so close to each other and to the exact solution. Meep uses the finite difference method (which is more indicated for highly nonlinear problems) which does not have as good convergence characteristics for coarse meshes (typical of computer runs made in personal computers) as the finite element and the boundary element method .
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#1066
by
rfmwguy
on 08 Apr, 2016 21:19
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Tangent Alert - NASA PR today -
Direct Fusion Drive funded by NASA (Phase I):
http://tinyurl.com/jzno8v2http://www.psatellite.com/research/fusion.php"Equipped with this engine:
1. A single Delta IV Heavy could send a DFD powered spacecraft to orbit Pluto. It could reach Pluto in 4 years and while there provide over 1 MW of power for science and communications.
2. A small reusable craft, configured for 1 MW, could deploy and service the James Webb Telescope.
3. A human Mars orbital mission could be reduced to nine months roundtrip.
4. The Jupiter Icy Moons Mission could arrive in 1/4 of the time that it took the Galileo spacecraft.
5.Interstellar travel becomes closer to reality, with the 4.5 light year trip to Alpha Centuri taking 500 years."
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#1067
by
Monomorphic
on 08 Apr, 2016 21:39
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Another tangent alert. SpaceX just stuck their barge landing! Mars here we come...
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#1068
by
otlski
on 08 Apr, 2016 22:42
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If Dr Rodal is correct I cannot hope to see more than nano Newtons from a 60GHz frustum, not practically measurable. Not keen to abandon what has been an expensive build I feel I should take the opportunity to try something new, such as an array of resonators. Local RF engineers have been understandably derisory so I have a long list of questions I would like to ask.
Yes, I will try to construct my questions better, meantime please let me know if this is the wrong forum to bring such questions to. As for transducers, that depends what is available at the time.
Sounds like you are indeed at the right forum. I can only advise regarding measurement instruments and techniques. Others here would have to weigh in to answer the rest of your questions.
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#1069
by
rq3
on 09 Apr, 2016 01:20
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Tangent Alert - NASA PR today -
Direct Fusion Drive funded by NASA (Phase I): http://tinyurl.com/jzno8v2
http://www.psatellite.com/research/fusion.php
"Equipped with this engine:
1. A single Delta IV Heavy could send a DFD powered spacecraft to orbit Pluto. It could reach Pluto in 4 years and while there provide over 1 MW of power for science and communications.
2. A small reusable craft, configured for 1 MW, could deploy and service the James Webb Telescope.
3. A human Mars orbital mission could be reduced to nine months roundtrip.
4. The Jupiter Icy Moons Mission could arrive in 1/4 of the time that it took the Galileo spacecraft.
5.Interstellar travel becomes closer to reality, with the 4.5 light year trip to Alpha Centuri taking 500 years."
When NACA morphed into NASA to beat the Russians to the moon, the US government lost all respect regarding basic research, in my not so humble opinion. We haven't got the testicular fortitude to complete a project as important as the Large Hadron Collider, but we can spend tax payers' dollars to fund whimsical "what if" fusion rockets to Pluto? Shouldn't we have a functional fusion reactor on the ground before we start funding them on expeditions to Pluto?
This isn't an issue of "all research is potentially good", it's just a bloody waste of money.
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#1070
by
rq3
on 09 Apr, 2016 01:22
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Another tangent alert. SpaceX just stuck their barge landing! Mars here we come...
And done by a private corporation, with minimal NASA funding.
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#1071
by
FattyLumpkin
on 09 Apr, 2016 01:33
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OK, I double checked my math...as far as dimensions only one (small?) change: SD = 5.6818
This is a scaled down version of the NASA frustum which was tested in TM212 and TE012 modes. The frequency for the best TE mode was 1.8804Ghz which scales up to 5.2538 GHz with RF being fed by dielectric from top of frustum (as is known), 2.6 Watts power is all that was used for this----a scaled down power injection amount would = 0.93057 Watt. TE012 If that doesn't work, I'll need a good talking to about my methods---> small LOL
FL
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#1072
by
Elmar Moelzer
on 09 Apr, 2016 02:02
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We haven't got the testicular fortitude to complete a project as important as the Large Hadron Collider, but we can spend tax payers' dollars to fund whimsical "what if" fusion rockets to Pluto? Shouldn't we have a functional fusion reactor on the ground before we start funding them on expeditions to Pluto?
There is too little funding for nuclear fusion research in the US. So many fusion research institutions are creative and search for other uses for their technology to get funding. I am almost certain that this is the case here. The reactor would probably work on earth as well, but with the current abysmal funding situation, a fusion space drive can most paradoxically get more money than a terrestrial fusion reactor.
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#1073
by
FattyLumpkin
on 09 Apr, 2016 02:15
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Re rfmvguy's remarks: T.E.S.S. : Transiting Exoplanet Survey Satellite is going up next year and followed by James Webb Space Telescope. Statistically, TESS will identify anywhere from 3 to 10 Earth analogues between 8 and 30 LYs distant, orbiting Sun-like stars in their Goldilocks zone(s). JWST is the second step in the evaluation of elements in said planet's atmospheres. Terrestrial Planet Finder now on hold would be forced into deployment, and if there is but one planet that gets the thumbs up in all categories, I would assert that that we need something as promising as the EM Drive.
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#1074
by
rfmwguy
on 09 Apr, 2016 02:37
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We haven't got the testicular fortitude to complete a project as important as the Large Hadron Collider, but we can spend tax payers' dollars to fund whimsical "what if" fusion rockets to Pluto? Shouldn't we have a functional fusion reactor on the ground before we start funding them on expeditions to Pluto?
There is too little funding for nuclear fusion research in the US. So many fusion research institutions are creative and search for other uses for their technology to get funding. I am almost certain that this is the case here. The reactor would probably work on earth as well, but with the current abysmal funding situation, a fusion space drive can most paradoxically get more money than a terrestrial fusion reactor.
Nice analysis...one of the reasons emdrive and other propulsion projects are gathering so much attention is the slow recognition of how big space is and how limited our current technology is to send out missions.
Pluto was a 12 year mission...one way...tons of discovery. We would love to go back sooner than 12 years.. Mars is now a goal...it will be a long mission.
Space needs new physics to get anywhere fast...sort out the emdrive and all the rest, the goal and payoff seems obvious. Worst thing imho is the failure to explore new concepts.
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#1075
by
FattyLumpkin
on 09 Apr, 2016 03:52
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rfmwguy, what is the fusion rocket you've show us using/burning for fuel? First am waiting mostly for EW labs paper, but second ITAR is supposed to come on line soon. Don't know if they'll be able to achieve containment without the plasma squirting out somewhere....analogous to trying to nail Jell-O to the wall (and make it stay).
Before moving into the more "esoteric" EM drive, I performed research on IS travel with the use of fusion as propulsion for the spacecraft. In my estimation PJMIF "Plasma Jet Magneto Inertial Fusion" was the only thing that was feasible. All of the fusion designs a gargantuan...nonetheless Icarus Interstellar picked "Firefly" as their flagship Z-pinch Deuterium fusion (a veritable neutron machine) Attached are some of the most recent specs on the craft, not the length and the mass. The large yellow fins/wings are advanced phase charge radiators. I consider this untenable and therefore say again this is why we need EM Drive!!!
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#1076
by
Elmar Moelzer
on 09 Apr, 2016 05:14
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rfmwguy, what is the fusion rocket you've show us using/burning for fuel? First am waiting mostly for EW labs paper, but second ITAR is supposed to come on line soon. Don't know if they'll be able to achieve containment without the plasma squirting out somewhere....analogous to trying to nail Jell-O to the wall (and make it stay).
Before moving into the more "esoteric" EM drive, I performed research on IS travel with the use of fusion as propulsion for the spacecraft. In my estimation PJMIF "Plasma Jet Magneto Inertial Fusion" was the only thing that was feasible. All of the fusion designs a gargantuan...nonetheless Icarus Interstellar picked "Firefly" as their flagship Z-pinch Deuterium fusion (a veritable neutron machine) Attached are some of the most recent specs on the craft, not the length and the mass. The large yellow fins/wings are advanced phase charge radiators. I consider this untenable and therefore say again this is why we need EM Drive!!!
Check out MSNWs fusion driven rocket. It has relatively high thrust (and still a great ISP) and could do a small scale Mars mission within 30 days with a spacecraft small enough to be launched by a single SLS launch.
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#1077
by
FattyLumpkin
on 09 Apr, 2016 07:33
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ECR-GDM Electron Cyclotron Resonance Gas Dynamic Mirror---so far as close as we can get to the fusion rocket:
1,960,000 m/s and 47,000 Newtons thrust Mass and therefore T/W ratio unknown. I think we a re deviating from the subject at hand though...notwithstanding pics of Federation Starships posted the other day.
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#1078
by
rfmwguy
on 09 Apr, 2016 09:43
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rfmwguy, what is the fusion rocket you've show us using/burning for fuel? First am waiting mostly for EW labs paper, but second ITAR is supposed to come on line soon. Don't know if they'll be able to achieve containment without the plasma squirting out somewhere....analogous to trying to nail Jell-O to the wall (and make it stay).
Before moving into the more "esoteric" EM drive, I performed research on IS travel with the use of fusion as propulsion for the spacecraft. In my estimation PJMIF "Plasma Jet Magneto Inertial Fusion" was the only thing that was feasible. All of the fusion designs a gargantuan...nonetheless Icarus Interstellar picked "Firefly" as their flagship Z-pinch Deuterium fusion (a veritable neutron machine) Attached are some of the most recent specs on the craft, not the length and the mass. The large yellow fins/wings are advanced phase charge radiators. I consider this untenable and therefore say again this is why we need EM Drive!!!
Yes, its not an emdrive but related by the simple notion that new propulsion ideas are being funded for the shrimking of mission times...what the emdrive is hoping to do.
A related topic can sometimes grow its own legs on this topic thread and form a separate one by itself. Any user in good standing can create a new topic in the new physics section at nsf. Sometimes they take off, sometimes they don't.
This fusion propulsion idea might qualify for a new topic by itself if there's enough interest.
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#1079
by
rfmwguy
on 09 Apr, 2016 14:03
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NSF-1701A Update - Suggestion Needed
OK, been looking into a Cavendish Torsion conversion on my teeter-totter test stand. Pretty simple actually. One big question:
Q: How would you suggest to calibrate in horizontal displacement?
Teeter-totter was easy enough, place a calibrated weight direct above 4 point harness attachment to beam, directly above emdrive.
Thanks,
Dave
I had no idea you were going to perform a sim on it. Perhaps you can try the above mentioned frequency(s). If I did the math correctly it should look quite good (a scaled down version of NASA's TM212, 91.2 micro-Newton model). Thanks for your time! 
, FL 
FL