...Quote from: TheTraveller on 10/30/2015 11:04 pmHow much Force do you need a cubesat EMDrive to deliver? Knowing the Force desired then the needed Rf watts can be calculated. Your job to deliver those Rf watts and ensure there is enough primary power available. Can design to many dimensions knowing the Rf drive freq, which will need to real time track lowest VSWR or lowest reflected power to achieve and hold resonance. I assume it needs to fit inside 1 cube being 100mmx100mmx100mm?To fit in a 12u cubesat, large dia can be up to 20cm with length up to 36cm. To accelerate a 10Kg cubesat at 10mm/s would take...what... 100mN? I'm guessing on the math here - too late at night - I'm probably off by some powers of 10... We can give you a KW for several minutes once per orbit, only limit is how hot the batteries get and how far we discharge them. More than a 20% depth of discharge will limit their life, but this is probably a limited life test anyway (not a multi-year mission) so we can maybe run them harder and/or pack in more batteries to give us more instantaneous power...
How much Force do you need a cubesat EMDrive to deliver? Knowing the Force desired then the needed Rf watts can be calculated. Your job to deliver those Rf watts and ensure there is enough primary power available. Can design to many dimensions knowing the Rf drive freq, which will need to real time track lowest VSWR or lowest reflected power to achieve and hold resonance. I assume it needs to fit inside 1 cube being 100mmx100mmx100mm?
Pesentation of a Iodine Ion Thruster for CubeSat with its main performances. Comparison with EMDrive or Woodward thruster would be instructive.
As the EM Drive does not use fuel it does not have a Delta-V limit. It is limited by sun light and the lifetime of the components. For deep space missions sunlight can be replaced by electricity from a nuclear source.
However, Shawyers is the only one that seems to have generated significant thrust, as he hasn't published any papers detailing the specs of his drive.
No they don't bounce. They get absorbed by the end plate and reemitted.If you are EM trained then please explain to me how a 8.8mm diameter waveguide can propagate a 4.12GHz EM wave? In fact neither can the big end at 3.52mm diameter propagate that EM wave. So both ends of the proposed Egan cavity are well below cutoff and can NOT propagate a 4.12GHz EM wave, yet he claims resonance....BTW please show me where Egan is EM trained or experienced? All I can find is he holds a BS in Maths and is a sifi writer and programmer. What amazes me is despite Egan having apparently no microwave training nor experience, so many EMDrive deniers jumped on this paper and totally ignored his apparent lack of credibility in the black arts of microwave waveguide physics.
Quote from: zellerium on 10/29/2015 02:52 pmQuote from: meberbs on 10/29/2015 12:23 pmAccording to your logic, no resonances could exist at all in a cone shaped cavity. That is an incorrect claim, easily testable by experiment. ...I think you missed the key work efficiently in TT's post. Yes of course you can get any shape to resonate, but to resonate with high quality and low losses we want to minimize the evanescent decay. When wave bounces off an opening because its wavelength is too large to fit, some energy will still propagate into the opening and decay exponentially. I believe what he and Shawyer are getting at is we should have each side of the resonator be above the cutoff, not that we have to. Correct.The only way to achieve a high Q is to ensure the small end operates above cutoff. If your end plates are spherical this also encourages the EM waves to form matching spherical wave fronts, which reduces significantly bounce phase distortion and also reduces side wall radiation pressure to almost nothing.
Quote from: meberbs on 10/29/2015 12:23 pmAccording to your logic, no resonances could exist at all in a cone shaped cavity. That is an incorrect claim, easily testable by experiment. ...I think you missed the key work efficiently in TT's post. Yes of course you can get any shape to resonate, but to resonate with high quality and low losses we want to minimize the evanescent decay. When wave bounces off an opening because its wavelength is too large to fit, some energy will still propagate into the opening and decay exponentially. I believe what he and Shawyer are getting at is we should have each side of the resonator be above the cutoff, not that we have to.
According to your logic, no resonances could exist at all in a cone shaped cavity. That is an incorrect claim, easily testable by experiment. ...
Quote from: Mezzenile on 10/31/2015 04:02 amPesentation of a Iodine Ion Thruster for CubeSat with its main performances. Comparison with EMDrive or Woodward thruster would be instructive.Any idea what the BIT-3 thruster, complete and ready to fly package costs to buy retail?
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Quote from: TheTraveller on 10/31/2015 05:02 amQuote from: Mezzenile on 10/31/2015 04:02 amPesentation of a Iodine Ion Thruster for CubeSat with its main performances. Comparison with EMDrive or Woodward thruster would be instructive.Any idea what the BIT-3 thruster, complete and ready to fly package costs to buy retail?The iodine thruster should very price competitive versus state of the art argon thruster as it does not require to accomodate on board the satellite a high pression tank to store the propelant. The accomodation of such a tank on a small satellite can be a burden (mass, security aspects, testing ...).Argon has still the advantage over iodine, having a very low chemical activity, to produce minimal erosion where the plume is in contact with the thruster or satellite structure.
Quote from: Mezzenile on 10/31/2015 05:31 amQuote from: TheTraveller on 10/31/2015 05:02 amQuote from: Mezzenile on 10/31/2015 04:02 amPesentation of a Iodine Ion Thruster for CubeSat with its main performances. Comparison with EMDrive or Woodward thruster would be instructive.Any idea what the BIT-3 thruster, complete and ready to fly package costs to buy retail?The iodine thruster should very price competitive versus state of the art argon thruster as it does not require to accomodate on board the satellite a high pression tank to store the propelant. The accomodation of such a tank on a small satellite can be a burden (mass, security aspects, testing ...).Argon has still the advantage over iodine, having a very low chemical activity, to produce minimal erosion where the plume is in contact with the thruster or satellite structure.My interest in the BIT-3 thruster price point was serious as I'm setting up to move into commercial EMDrive production. If there is sufficient commercial interest, it would be possible to produce a 2mN EMDrive that would fit in a 1U cubesat form factor and draw around 15Ws of power.So any feedback on the price point of 2mN thrust equivalent ion drives would be of genuine interest.Design spreadsheet confirms it should be possible to build a X band EMDrive frustum that would fit inside a 10x10x10cm 1U cubesat module and generate 2mN of continual thrust using 15Ws or less of power. Might even be able to electronically vector the thrust angle and provide 2 axis directional control.
Your TE11 cutoff equation is incorrect as you used the diameter and not the radius.
QuoteBiggest issue I see is sourcing a low mass and highly efficient min 200W solid state Rf amp AND dealing with the 800Ws of waste heat. Maybe better to go for a lower output power Rf amp that can run 24/7, instead of doing short bursts of acceleration.Suggestion from the peanut gallery:use the waste heat to generate electricity. (thermocouples?) Won't get anywhere near unity, but might offset the power bill some.
Biggest issue I see is sourcing a low mass and highly efficient min 200W solid state Rf amp AND dealing with the 800Ws of waste heat. Maybe better to go for a lower output power Rf amp that can run 24/7, instead of doing short bursts of acceleration.
Quote from: VAXHeadroom on 10/31/2015 12:36 am...Quote from: TheTraveller on 10/30/2015 11:04 pmHow much Force do you need a cubesat EMDrive to deliver? Knowing the Force desired then the needed Rf watts can be calculated. Your job to deliver those Rf watts and ensure there is enough primary power available. Can design to many dimensions knowing the Rf drive freq, which will need to real time track lowest VSWR or lowest reflected power to achieve and hold resonance. I assume it needs to fit inside 1 cube being 100mmx100mmx100mm?To fit in a 12u cubesat, large dia can be up to 20cm with length up to 36cm. To accelerate a 10Kg cubesat at 10mm/s would take...what... 100mN? I'm guessing on the math here - too late at night - I'm probably off by some powers of 10... We can give you a KW for several minutes once per orbit, only limit is how hot the batteries get and how far we discharge them. More than a 20% depth of discharge will limit their life, but this is probably a limited life test anyway (not a multi-year mission) so we can maybe run them harder and/or pack in more batteries to give us more instantaneous power...I'm not sure where you are going here, mm/s is a velocity, not an acceleration. I have made my concerns about an amateur space test known previously. In my opinion, the disturbing orbital forces, thermal and EM effects on a satellite this small may not be appreciably smaller than the effects folks are trying to eliminate in the lab. What would you conclude from a cubesat test that doesn't give detectable results?
Quote from: VAXHeadroom on 10/31/2015 12:36 am...Quote from: TheTraveller on 10/30/2015 11:04 pmHow much Force do you need a cubesat EMDrive to deliver? Knowing the Force desired then the needed Rf watts can be calculated. Your job to deliver those Rf watts and ensure there is enough primary power available. Can design to many dimensions knowing the Rf drive freq, which will need to real time track lowest VSWR or lowest reflected power to achieve and hold resonance. I assume it needs to fit inside 1 cube being 100mmx100mmx100mm?To fit in a 12u cubesat, large dia can be up to 20cm with length up to 36cm. To accelerate a 10Kg cubesat at 10mm/s would take...what... 100mN? I'm guessing on the math here - too late at night - I'm probably off by some powers of 10... We can give you a KW for several minutes once per orbit, only limit is how hot the batteries get and how far we discharge them. More than a 20% depth of discharge will limit their life, but this is probably a limited life test anyway (not a multi-year mission) so we can maybe run them harder and/or pack in more batteries to give us more instantaneous power...Quick analysis suggest the 20cm big end limitation reduces the Df ( F = (2 Df unloadedQ P) / c ) quite a bit. But working on that limitation I get a highly optimised small end of 14.95cm and length of 15.07cm (mode TE011 @ 2.45GHz), with spherical end plates, using a 20% solid state amp conversion efficiency to Rf and 1kW power input could deliver, at a conservative unloaded Q of 50,000 (25,000 as measured loaded Q) around 40mN, generating say 4mm/sec acceleration with a 10kg mass.