Quote from: TheTraveller on 05/01/2015 05:10 pmQuote from: gospacex on 05/01/2015 03:16 pmQuote from: TheTraveller on 05/01/2015 02:54 pmQuote from: ppnl on 05/01/2015 02:37 pmA Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.Ion drive / Hall thruster / Vasimr uses fuel & electrical power. As long as it has fuel and electrical power, it can continuously accelerate or decelerate. Initially increasing craft velocity & kinetic energy, until it must turn 180 deg and decelerate to obtain orbit.EMDrive does the same.Gosh.IT IS NOT THE SAME!!!!!!Having reaction mass expelled *changes everything*! For one, now you need to include reaction mass' kinetic energy into energy balance.Constant acceleration reactionless drive of any type violates COE.EMDrive violates the Rocket Equation as no ISP from expelled high velocity fuel mass but not overall COE. The kinetic energy gain of the accelerated mass is matched by that drawn from the primary energy source, minus losses.See Shawyer's equations for dynamic operation:http://www.emdrive.com/theorypaper9-4.pdfApologies if my explanations fails to convey how EMDrive works different to expelled mass rocket engine. Suggest need to stop comparing to conventional rocket engine and focus on overall primary energy input to final accelerating mass kinetic energy gain.Actually he seems to be claiming that there is no constant acceleration with constant power input. If so then there may be no COE violation but we are back to the problem of a preferred frame of reference. And your ship will preform very differently in December than in June because of the orbit of the earth putting it in a different inertial reference frame.
Quote from: gospacex on 05/01/2015 03:16 pmQuote from: TheTraveller on 05/01/2015 02:54 pmQuote from: ppnl on 05/01/2015 02:37 pmA Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.Ion drive / Hall thruster / Vasimr uses fuel & electrical power. As long as it has fuel and electrical power, it can continuously accelerate or decelerate. Initially increasing craft velocity & kinetic energy, until it must turn 180 deg and decelerate to obtain orbit.EMDrive does the same.Gosh.IT IS NOT THE SAME!!!!!!Having reaction mass expelled *changes everything*! For one, now you need to include reaction mass' kinetic energy into energy balance.Constant acceleration reactionless drive of any type violates COE.EMDrive violates the Rocket Equation as no ISP from expelled high velocity fuel mass but not overall COE. The kinetic energy gain of the accelerated mass is matched by that drawn from the primary energy source, minus losses.See Shawyer's equations for dynamic operation:http://www.emdrive.com/theorypaper9-4.pdfApologies if my explanations fails to convey how EMDrive works different to expelled mass rocket engine. Suggest need to stop comparing to conventional rocket engine and focus on overall primary energy input to final accelerating mass kinetic energy gain.
Quote from: TheTraveller on 05/01/2015 02:54 pmQuote from: ppnl on 05/01/2015 02:37 pmA Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.Ion drive / Hall thruster / Vasimr uses fuel & electrical power. As long as it has fuel and electrical power, it can continuously accelerate or decelerate. Initially increasing craft velocity & kinetic energy, until it must turn 180 deg and decelerate to obtain orbit.EMDrive does the same.Gosh.IT IS NOT THE SAME!!!!!!Having reaction mass expelled *changes everything*! For one, now you need to include reaction mass' kinetic energy into energy balance.Constant acceleration reactionless drive of any type violates COE.
Quote from: ppnl on 05/01/2015 02:37 pmA Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.Ion drive / Hall thruster / Vasimr uses fuel & electrical power. As long as it has fuel and electrical power, it can continuously accelerate or decelerate. Initially increasing craft velocity & kinetic energy, until it must turn 180 deg and decelerate to obtain orbit.EMDrive does the same.
A Hall thruster is just a rocket and like any rocket it takes its reaction mass with it so it can have constant acceleration with (apparent) constant power. That would suggest that it does better than a electric car which can't accelerate constantly with constant power. But that is an illusion. The Hall thruster is using massive amounts of energy to accelerate its reaction mass and as a result it will always do much worse than the car. A rocket will always run out of fuel long before its kinetic energy exceeds the energy content of its fuel.
Quote from: TheTraveller on 05/01/2015 05:10 pmThe kinetic energy gain of the accelerated mass is matched by that drawn from the primary energy source, minus losses.This implies that there's a preferred frame of reference, which in turn implies that the thrust and the efficiency of the EM drive depends on it's orientation (because the Earth is moving through space) and on the time of day (because the Earth is rotating and thereby changing the experiment's velocity relative to the preferred frame of reference).
The kinetic energy gain of the accelerated mass is matched by that drawn from the primary energy source, minus losses.
Couldn't it be a local inertial frame instead? With the inertial frame at any given point in space being tied to the local gravitational potential at that point (in this case, that of the Earth being dominant)?
Quote from: AdrianW on 05/01/2015 05:48 pmQuote from: TheTraveller on 05/01/2015 05:10 pmThe kinetic energy gain of the accelerated mass is matched by that drawn from the primary energy source, minus losses.This implies that there's a preferred frame of reference, which in turn implies that the thrust and the efficiency of the EM drive depends on it's orientation (because the Earth is moving through space) and on the time of day (because the Earth is rotating and thereby changing the experiment's velocity relative to the preferred frame of reference).Couldn't it be a local inertial frame instead? With the inertial frame at any given point in space being tied to the local gravitational potential at that point (in this case, that of the Earth being dominant)?(Actually the local inertial field, defined in this way, might just be the definition of the local gravitational field.)
....I have a strong interest in this effort and have been looking at different approaches that might be able to move the work to a more powerful foundation. My sense is that the strongest platform would empower the assembly of the right people to work the problem and resource them with the tools to do it right, without either hamstringing them with bureaucracy or the narrow interest of typical "VC-funded" enterprise.....
While your cavity and ours arn't exactly the same one could say the situations are quite similar. The NASA Eagleworks system operated at 935MHz at (?)W, Roger Shawyer 2.45GHz at 850W, and Dr Yang at (?)MHz at 2.5KW (apologize if these missing values have been published, I didn't immediately see them).
Quote from: jknuble on 05/01/2015 06:33 pmGood luck, I can pass you some names off-line if that is of interest. If you havn't already, it would be useful to consult a high-power RF engineer, not necessarily and EM physicist (sorry guys! ). As stated, I am not an expert on this phenomenon but if there are further questions I can perhaps pass them along.-Joseph Knuble(Also, I hope I'm wrong!) My understanding is the current setup is a little over 1.9 GHz @ 50 watts.From what I can find out online, the end caps of the cavity are single sided FR4, but I couldn't find out if they were baked and post coated or not. Do you think they could be getting some out gassing or other effects from the FR4? Would glass Teflon be a better choice of dielectric?
Good luck, I can pass you some names off-line if that is of interest. If you havn't already, it would be useful to consult a high-power RF engineer, not necessarily and EM physicist (sorry guys! ). As stated, I am not an expert on this phenomenon but if there are further questions I can perhaps pass them along.-Joseph Knuble(Also, I hope I'm wrong!)
Dr. Rodal:"That amplitude, frequency and phase modulation of the carrier wave results in greater thrust force is a prediction from Dr. White's computer code, and not yet an experimentally proven fact."I think I may have verified today the need for large time rate of change of the resonant circuit phase changes as the RF amplifier driven 1,937.088 MHz, +/- ~25kHz sine wave oscillates back and forth through the resonance frequency of the frustum cavity. Through a methodical tuning campaign using our triple stub Z-matching tuner and 2 feet of RG-8 coax as the main transmission line to the frustum, I marched the Smith Chart solution circle around its impedance space while checking the thrust output for each over a dozen stub tuner configurations. Only those tuning solutions that maximized the phase change through resonance over the smallest frequency span generated the largest thrust signatures and in fact it overcame its lower Q-factors that those solutions provided. In fact a running solution that yielded Q-factor solutions as high as 7,500 were out performed by two or even three to one in thrust output by tuning solutions that had half these peak Q-factors, but maximized the resonant phase change per kHz. And yes, the input power was maintained at around 50W for all tests. More data later this week as I continue this investigation.BTW, our Eagleworks Dynamics of the Quantum Vacuum paper has finally been published on the NASA/NTRS server. You can find it here: http://tinyurl.com/mw64rsnBest, Paul M.
Quote from: jknuble on 05/01/2015 06:33 pm While your cavity and ours arn't exactly the same one could say the situations are quite similar. The NASA Eagleworks system operated at 935MHz at (?)W, Roger Shawyer 2.45GHz at 850W, and Dr Yang at (?)MHz at 2.5KW (apologize if these missing values have been published, I didn't immediately see them). Welcome to the thread and the site.Eagleworks studies were done around 100W power level. However they did comment that it needed an HDPE insert in the cavities to make it work.
Largely to unconstrain the research from:A) Resources allocated by these specific institutions; B) Institutional politicsThere is absolutely no reason why the efforts at Glenn, JPL, etc. couldn't or shouldn't be run in-parallel, but the ability to combine material resources with the open contribution of everyone in the world who is interested in the project ("open source R&D"?) presents a potentially powerful addition. We have reason to believe (cf the original X-prize, the work at SpaceX, etc.) that these kinds of "entrepreneurial" R&D can do things that existing institutions can't.I'd suggest, for example, that the synergy of many of the good folks on this forum with the work at Eagleworks (including notably your recent excellent article) is a sample of what could be done. A properly architected crowd/funded + crowdsourced R&D effort could be extremely powerful.
Competitors around the world are increasing their investment in basic research, but science funding in the U.S. federal budget is at "the lowest it has been since the Second World War as a fraction of the federal budget," says MIT physicist Marc Kastner, who led the committee that wrote the report. "This really threatens America's future."
3) Work the other way around - crowd-fund an X-prize for some key milestone in EM Drive research. Say a $5M bounty for the first team that can generate material (say 1N) thrust.Notably, we could really be innovative and use something like a scamfunding mechanism. Why not? A "decentralized collaborative organization" might be precisely the thing necessary to resource research on the EM Drive while keeping the results open to the public.
Quote from: jordan.greenhall on 05/01/2015 07:10 pmLargely to unconstrain the research from:A) Resources allocated by these specific institutions; B) Institutional politicsThere is absolutely no reason why the efforts at Glenn, JPL, etc. couldn't or shouldn't be run in-parallel, but the ability to combine material resources with the open contribution of everyone in the world who is interested in the project ("open source R&D"?) presents a potentially powerful addition. We have reason to believe (cf the original X-prize, the work at SpaceX, etc.) that these kinds of "entrepreneurial" R&D can do things that existing institutions can't.I'd suggest, for example, that the synergy of many of the good folks on this forum with the work at Eagleworks (including notably your recent excellent article) is a sample of what could be done. A properly architected crowd/funded + crowdsourced R&D effort could be extremely powerful.QuoteCompetitors around the world are increasing their investment in basic research, but science funding in the U.S. federal budget is at "the lowest it has been since the Second World War as a fraction of the federal budget," says MIT physicist Marc Kastner, who led the committee that wrote the report. "This really threatens America's future."http://www.infoworld.com/article/2917200/government/mit-report-cuts-to-federal-funding-threaten-the-countrys-future.html
Since Eagleworks started doing real work on the EM Drive, there has been growing interest from outside in finding ways to support their work. So far this has been frustrated largely due to NASA regulations (you can't donate money, equipment, etc. directly to a NASA project). There are some work-arounds ([through the SSI](www.ssi.org)) but these are uninspiring.I have a strong interest in this effort and have been looking at different approaches that might be able to move the work to a more powerful foundation. My sense is that the strongest platform would empower the assembly of the right people to work the problem and resource them with the tools to do it right, without either hamstringing them with bureaucracy or the narrow interest of typical "VC-funded" enterprise.Given that, I can see three more aggressive approaches to funding EM Drive research:1) Convince the Eagleworks crew to take their work outside of NASA and fund the efforts directly. After some research I'm reasonably confident that some form of crowdfunding could be expected to be able to raise $2.5M to $5M for this kind of effort. Would that be enough to a) get the Eagleworks crew feeling safe to make the leap; and b) provide the materials and resources necessary to really kick the tires on this thing? Hard to say - but we should note that an effort like this would also open the doors on allowing interested allies loan equipment. Which is to say that you could likely get a nice multiplier on actual cash contributions. 2) Assemble some other team than the Eagleworks team and fund them to do the research in a similar manner to the above. This could be a sort of public/private combo where two teams collaborate to enhance each-other's work. The gating item here, of course, would be the team - what is the right mix of people to get this done right? 3) Work the other way around - crowd-fund an X-prize for some key milestone in EM Drive research. Say a $5M bounty for the first team that can generate material (say 1N) thrust.Notably, we could really be innovative and use something like a scamfunding mechanism. Why not? A "decentralized collaborative organization" might be precisely the thing necessary to resource research on the EM Drive while keeping the results open to the public.I am in a position that I could organize any of these three and would be delighted to collaborate to make any of them happen. Obviously, #1 is gated by the eagleworks team and #2 is gated by identifying and assembling an alternate team. I'm interested in the thoughts of those folks who have been close to the developments (and the people) so far.