-
#1200
by
Tellmeagain
on 04 Jan, 2016 01:48
-
Other than as it affects experimental results, why would Lorentz forces be a problem for a satellite or other space application?
Are you talking about the "huge surface lorentz force"? If so, you may know that It has another name, "radiation pressure".
-
#1201
by
oyzw
on 04 Jan, 2016 02:02
-
Other than as it affects experimental results, why would Lorentz forces be a problem for a satellite or other space application?
Are you talking about the "huge surface lorentz force"? If so, you may know that It has another name, "radiation pressure".
Very true! In terms of nature, the Emdrive thrust is its.I have seen an article mentioned: the Chinese academy of sciences of superconducting niobium rf cavity at work, can produce a powerful inner surface lorentz force, powerful (more than 3000 N) to make the cavity shell bending and vibration.
-
#1202
by
TheTraveller
on 04 Jan, 2016 03:06
-
Interesting info:
https://curvity.org/blog/research-summary/research-proposal/After a thirty-year career in microwave engineering, a British engineer named Roger Shawyer decided to investigate an anomaly that had plagued superconducting linear accelerators.
Linear accelerators use high power resonating chambers to increase the speed of the particles as they pass through and in doing so, ran into a problem with the cavities detuning [2][3].
At full power, the cavities were decreasing their lengths slightly.
In 2001 after retiring from his job at EADS Astrium, he created a company with external funding to see if the force that was causing the detuning could be used for propulsion[4].
-
#1203
by
SteveD
on 04 Jan, 2016 03:24
-
Interesting info:
https://curvity.org/blog/research-summary/research-proposal/
After a thirty-year career in microwave engineering, a British engineer named Roger Shawyer decided to investigate an anomaly that had plagued superconducting linear accelerators.
Linear accelerators use high power resonating chambers to increase the speed of the particles as they pass through and in doing so, ran into a problem with the cavities detuning [2][3].
At full power, the cavities were decreasing their lengths slightly.
In 2001 after retiring from his job at EADS Astrium, he created a company with external funding to see if the force that was causing the detuning could be used for propulsion[4].
Interesting. I take it the proposal in question did not get funding?
-
#1204
by
TheTraveller
on 04 Jan, 2016 03:37
-
Interesting info:
https://curvity.org/blog/research-summary/research-proposal/
After a thirty-year career in microwave engineering, a British engineer named Roger Shawyer decided to investigate an anomaly that had plagued superconducting linear accelerators.
Linear accelerators use high power resonating chambers to increase the speed of the particles as they pass through and in doing so, ran into a problem with the cavities detuning [2][3].
At full power, the cavities were decreasing their lengths slightly.
In 2001 after retiring from his job at EADS Astrium, he created a company with external funding to see if the force that was causing the detuning could be used for propulsion[4].
Interesting. I take it the proposal in question did not get funding?
Checking on the current status is in progress.
-
#1205
by
Prunesquallor
on 04 Jan, 2016 04:06
-
...
I suspect that if Paul could put on a vac suit and do his manual tuning inside the vac chamber, that the vac Force results would be much higher.
...
Well, you certainly wouldn't do it THAT way. Humans in spacesuits in vacuum chambers are complex, hazardous and expensive operations. You would do the tuning remotely, somehow.
-
#1206
by
RFPlumber
on 04 Jan, 2016 04:16
-
"1/2 Loop Antenna"
...
This 1/2 loop also fits the design of the multi loop coupler I plan to test as in the 4th attachment. That design may grow to 4 - 8 individually driven loops, equally spaced and installed at the same radius from the big end centre. Or maybe the 2 or 3 or 4 loop coupler will prove to do the job well enough. Nice feature about the internally connected 2 or 3 or 4 x 1/2 loops is there is no need for an external coax splitter and multiple install sites in the big end.
...
W.r.t. using "4 - 8 individually driven loops", my understanding is this requires all of the following:
1. All splitter outputs to be in phase.
2. Coax connections from splitter to loops be of the exact same length.
3. Cavity magnetic field at each of the loop locations to be in phase.
IMHO, one multi-loop coupler is a much easier proposition.
P.S. Nice RF amp
Too heavy for my pendulum though.
P.S. Pure single freq RF excitation will not show any thrust anyway. This is my 2016 prediction.
-
#1207
by
SteveD
on 04 Jan, 2016 04:40
-
Just a thought might a lower frequency Frustum be easier to manufacture? I note the 70 cm HAM band at 420.0-450.0 MHz. I wonder what the regulations are for experimental devices in these frequencies? Hum maybe a frustum made of aerogel with a coat of conductive paint and silver electroplated over? (Not that anyone here has a budget for such things). If that actually moved down during a test, well I think it would surprise everyone.
Seriously though, could lowering the frequency unlock cheaper and easier to work with materials/equipment?
-
#1208
by
TheTraveller
on 04 Jan, 2016 05:01
-
Just a thought might a lower frequency Frustum be easier to manufacture? I note the 70 cm HAM band at 420.0-450.0 MHz. I wonder what the regulations are for experimental devices in these frequencies? Hum maybe a frustum made of aerogel with a coat of conductive paint and silver electroplated over? (Not that anyone here has a budget for such things). If that actually moved down during a test, well I think it would surprise everyone.
Seriously though, could lowering the frequency unlock cheaper and easier to work with materials/equipment?
Frustum dimensions scale with freq. At 0.45 GHz, TE013 frustum would be around 5 times longer than at 2.45 GHz.
Will do a 0.45 GHz design and report dimensions & expected N/kW.
-
#1209
by
TheTraveller
on 04 Jan, 2016 05:12
-
A 435 Mhz TE013 frustum design
Big end: 1.6 m dia
Small end: 0.85 m dia
Length: 1.7 m
Area: 9.28 m^2
Volume: 2.07 m^3
Df: 0.803
Resonance: 435.0 MHz
Qu: 162k
Specific Force: 0.434 N/kW
TC: 59.2 us, 5 x TC: 296.2 us
End to end transits per TC: 17,1777, per 5 TC: 85,885
BIG FRUSTUM!
-
#1210
by
oyzw
on 04 Jan, 2016 05:25
-
A 435 Mhz TE013 frustum design
Big end: 1.6 m dia
Small end: 0.85 m dia
Length: 1.7 m
Area: 9.28 m^2
Volume: 2.07 m^3
Df: 0.803
Resonance: 435.0 MHz
Qu: 162k
Specific Force: 0.434 N/kW
TC: 59.2 us, 5 x TC: 296.2 us
End to end transits per TC: 17,1777, per 5 TC: 85,885
BIG FRUSTUM!
Fill the microwave medium to reduce the volume
-
#1211
by
A_M_Swallow
on 04 Jan, 2016 05:27
-
A 435 Mhz TE013 frustum design
Big end: 1.6 m dia
Small end: 0.85 m dia
Length: 1.7 m
Area: 9.28 m^2
Volume: 2.07 m^3
Df: 0.803
Resonance: 435.0 MHz
Qu: 162k
Specific Force: 0.434 N/kW
TC: 59.2 us, 5 x TC: 296.2 us
End to end transits per TC: 17,1777, per 5 TC: 85,885
BIG FRUSTUM!
That could be a car engine. There are satellites that big.
Put in 100 kW and get 43 N out.
That would accelerate a 10 tonne satellite at 43/10000 = 0.0043 m/s/s
-
#1212
by
TheTraveller
on 04 Jan, 2016 05:27
-
A 435 Mhz TE013 frustum design
Big end: 1.6 m dia
Small end: 0.85 m dia
Length: 1.7 m
Area: 9.28 m^2
Volume: 2.07 m^3
Df: 0.803
Resonance: 435.0 MHz
Qu: 162k
Specific Force: 0.434 N/kW
TC: 59.2 us, 5 x TC: 296.2 us
End to end transits per TC: 17,1777, per 5 TC: 85,885
BIG FRUSTUM!
Fill the microwave medium to reduce the volume
Adding dielectric medium increases losses, kills Q and thrust.
-
#1213
by
zen-in
on 04 Jan, 2016 06:07
-
Just a thought might a lower frequency Frustum be easier to manufacture? I note the 70 cm HAM band at 420.0-450.0 MHz. I wonder what the regulations are for experimental devices in these frequencies? Hum maybe a frustum made of aerogel with a coat of conductive paint and silver electroplated over? (Not that anyone here has a budget for such things). If that actually moved down during a test, well I think it would surprise everyone.
Seriously though, could lowering the frequency unlock cheaper and easier to work with materials/equipment?
The 70 cm Ham band is a shared scientific band and is restricted below 440 MHz. Amateurs and scientific users are not permitted to use the lower part of the band if they are located near the Canadian border. I don't know what scientific uses are permitted. New uses have to be coordinated with the FCC. Amateur usage in the lower part of the band is mostly weak signal use - satellite links, meteor scatter, and long distance communication (dx). Any interference is quickly located and mitigated. Sometimes the FCC has to be involved.
-
#1214
by
TheTraveller
on 04 Jan, 2016 07:10
-
A 435 Mhz TE013 frustum design
Big end: 1.6 m dia
Small end: 0.85 m dia
Length: 1.7 m
Area: 9.28 m^2
Volume: 2.07 m^3
Df: 0.803
Resonance: 435.0 MHz
Qu: 162k
Specific Force: 0.434 N/kW
TC: 59.2 us, 5 x TC: 296.2 us
End to end transits per TC: 17,1777, per 5 TC: 85,885
BIG FRUSTUM!
That could be a car engine. There are satellites that big.
Put in 100 kW and get 43 N out.
That would accelerate a 10 tonne satellite at 43/10000 = 0.0043 m/s/s
At 33% efficiency on the 100kW Rf amp, will need 300kW dc to power it. That is a lot of solar panels!
4 such drives will need 1.2MWs of solar panels to gen 172Ns of thrust, with almost 1.2MWs of heat to get rid of in a vacuum.
So a few support system issues that need engineering optimal solutions.
-
#1215
by
oyzw
on 04 Jan, 2016 07:56
-
A 435 Mhz TE013 frustum design
Big end: 1.6 m dia
Small end: 0.85 m dia
Length: 1.7 m
Area: 9.28 m^2
Volume: 2.07 m^3
Df: 0.803
Resonance: 435.0 MHz
Qu: 162k
Specific Force: 0.434 N/kW
TC: 59.2 us, 5 x TC: 296.2 us
End to end transits per TC: 17,1777, per 5 TC: 85,885
BIG FRUSTUM!
That could be a car engine. There are satellites that big.
Put in 100 kW and get 43 N out.
That would accelerate a 10 tonne satellite at 43/10000 = 0.0043 m/s/s
At 33% efficiency on the 100kW Rf amp, will need 300kW dc to power it. That is a lot of solar panels!
4 such drives will need 1.2MWs of solar panels to gen 172Ns of thrust, with almost 1.2MWs of heat to get rid of in a vacuum.
So a few support system issues that need engineering optimal solutions.
Heat dissipation is a great challenge .Should use the travelling wave tube amplifier in the space
-
#1216
by
SteveD
on 04 Jan, 2016 08:34
-
Another night with difficulty sleeping. Guess the small Reddit fan club I seem to have gathered is going to like this (@Shell wasn't testy at you last time, was testy at some folks on Reddit).
KE = 1/2mv^2
Actually KE =1/2(mr + KE/c^2)v^2 where mr is the rest mass of the object. Solving for KE once you put in relativistic mass increases gets . . . interesting (a.k.a. its too late at night and I know I've got to be screwing up the math).
If you stop and think about that, it would seem like any constant mass, scheme with an efficiency greater than a photon rocket will hit a point where KE increase > energy input at some point on this side of the speed of light. The problem is constant thrust with constant power input. A sufficiently efficient Ion engine might also have a similar problem (reaches the point of KE increase > energy in before it runs out or propellant, not claiming this as true without more math). Photonic Laser Thrusters -- a device experimentally shown to exist -- also seem to suffer from this problem.
What discussion there has been about this has been looking for an error in the basic equation. What if the equation is right and there is a form of relativistic negative mass keeping the books balanced? As the object accelerates it both gains AND LOSES relativistic mass so that over unity does not occur until the object reaches the speed of light? If true wonder if negative mass could somehow explain the EMDrive effect?
Yeah, probably not -- but dropping the relativistic equation into the classical formula has me wondered if there aren't aspects of this issue that we are not considering.
-
#1217
by
TheTraveller
on 04 Jan, 2016 08:49
-
A 435 Mhz TE013 frustum design
Big end: 1.6 m dia
Small end: 0.85 m dia
Length: 1.7 m
Area: 9.28 m^2
Volume: 2.07 m^3
Df: 0.803
Resonance: 435.0 MHz
Qu: 162k
Specific Force: 0.434 N/kW
TC: 59.2 us, 5 x TC: 296.2 us
End to end transits per TC: 17,1777, per 5 TC: 85,885
BIG FRUSTUM!
That could be a car engine. There are satellites that big.
Put in 100 kW and get 43 N out.
That would accelerate a 10 tonne satellite at 43/10000 = 0.0043 m/s/s
At 33% efficiency on the 100kW Rf amp, will need 300kW dc to power it. That is a lot of solar panels!
4 such drives will need 1.2MWs of solar panels to gen 172Ns of thrust, with almost 1.2MWs of heat to get rid of in a vacuum.
So a few support system issues that need engineering optimal solutions.
Heat dissipation is a great challenge .Should use the travelling wave tube amplifier in the space
Efficiency data I've seen for TWT amps is not that good, especially as current gen Rf amps are around 33% efficiency.
However all a long way from maggies at 88% efficiency. OK sure there are issues with freq splatter but papers I've read show maggies can gen output bandwidths of +-5kHz, which is more than enough for non cryo frustums.
Consider a fluid cooled frustum with a 88% efficient 100kW magnetron as attached. Could even be liquid N2 cooled to boost Q 3x.
All doable with enough engineering hours & $$s.
-
#1218
by
Mulletron
on 04 Jan, 2016 09:00
-
Another night with difficulty sleeping. Guess the small Reddit fan club I seem to have gathered is going to like this (@Shell wasn't testy at you last time, was testy at some folks on Reddit).
KE = 1/2mv^2
Actually KE =1/2(mr + KE/c^2)v^2 where mr is the rest mass of the object. Solving for KE once you put in relativistic mass increases gets . . . interesting (a.k.a. its too late at night and I know I've got to be screwing up the math).
If you stop and think about that, it would seem like any constant mass, scheme with an efficiency greater than a photon rocket will hit a point where KE increase > energy input at some point on this side of the speed of light. The problem is constant thrust with constant power input. A sufficiently efficient Ion engine might also have a similar problem (reaches the point of KE increase > energy in before it runs out or propellant, not claiming this as true without more math). Photonic Laser Thrusters -- a device experimentally shown to exist -- also seem to suffer from this problem.
What discussion there has been about this has been looking for an error in the basic equation. What if the equation is right and there is a form of relativistic negative mass keeping the books balanced? As the object accelerates it both gains AND LOSES relativistic mass so that over unity does not occur until the object reaches the speed of light? If true wonder if negative mass could somehow explain the EMDrive effect?
Yeah, probably not -- but dropping the relativistic equation into the classical formula has me wondered if there aren't aspects of this issue that we are not considering.
A negative effective mass for photons has been recently realized. Can you find a negative photon effective mass inside an Emdrive?
http://www.extremetech.com/extreme/168771-researchers-seemingly-break-newtons-third-law-create-optical-diametric-driveMore links and paper in below post from thread 2.
https://forum.nasaspaceflight.com/index.php?topic=36313.msg1357829#msg1357829
-
#1219
by
TheTraveller
on 04 Jan, 2016 09:00
-
Another night with difficulty sleeping. Guess the small Reddit fan club I seem to have gathered is going to like this (@Shell wasn't testy at you last time, was testy at some folks on Reddit).
KE = 1/2mv^2
Actually KE =1/2(mr + KE/c^2)v^2 where mr is the rest mass of the object. Solving for KE once you put in relativistic mass increases gets . . . interesting (a.k.a. its too late at night and I know I've got to be screwing up the math).
If you stop and think about that, it would seem like any constant mass, scheme with an efficiency greater than a photon rocket will hit a point where KE increase > energy input at some point on this side of the speed of light. The problem is constant thrust with constant power input. A sufficiently efficient Ion engine might also have a similar problem (reaches the point of KE increase > energy in before it runs out or propellant, not claiming this as true without more math). Photonic Laser Thrusters -- a device experimentally shown to exist -- also seem to suffer from this problem.
What discussion there has been about this has been looking for an error in the basic equation. What if the equation is right and there is a form of relativistic negative mass keeping the books balanced? As the object accelerates it both gains AND LOSES relativistic mass so that over unity does not occur until the object reaches the speed of light? If true wonder if negative mass could somehow explain the EMDrive effect?
Yeah, probably not -- but dropping the relativistic equation into the classical formula has me wondered if there aren't aspects of this issue that we are not considering.
Others have also commented the potential breakage of constant accelerate CoE is not unique to the EmDrive.
While my rotary test will in no way get near the point of possible CofE violation, it will directly measure power supply > Rf amp > rotary test rig kinetic energy gain & associated conversion rates.
As far as I know, this will be the 1st public release of such data and should at least provide pointers as to what may happen, and if there is a possible CofE violation or not.
Too heavy for my pendulum though.