Quote from: aceshigh on 02/19/2015 07:07 pmthose mission parameters presupposed electrical power from solar panels? I guess that some good fission or fusion reactors (whenever fusion is available) would allow the addition of even more EM Drives and cut that mission time several times. Aceshigh:When it comes to manned solar electric propulsion missions, the largest to date proposed photovoltaic arrays for a human crewed missions are in the 300 kilowatt electric (kW-e) power range. However most of the Q-Thruster solar system based mission analysis we did last year assumed using a U235 fission based reactor with a closed-cycle brayton or rankine thermal to electrical power conversion cycle system in the 1.0-to-2.0 Megawatt electric (MW-e) class output with at least a 10 year lifetime. Now it's true that such a space based nuclear power reactor system has never been fielded, but that was due to a lack of a funded mission for same like sending humans to Mars, but more importantly, the lack of the political will to do so. However building such a space-based closed cycle electrical power reactor is technologically feasible and has been since the 1980s. Now like all naval propulsion system, once you've established the viability of a propulsion technique like the EM-Drive, and have an urgent need to do so, what comes next is developing the long lead items needed to power it. And all these electric space propulsion concepts for deep-space human missions, be they conventional ion, Hall or VASMIR type plasma rocket thrusters, or Q-thruster like space drives, go begging for an already developed nuclear power plant that is sized from 1.0 MWe up to 100 MWe output dependent on the mission scenario. I know that this sounds like a lot of power to the space community, but when it's compared to what the US Navy already builds for its nuclear submarine fleet like its "Boomer' Ohio class ICBM vehicles, which sport the 220 MW-thermal (MW-t) S8G reactor that fits in a 42 foot diameter by 55 feet long container and lasts for up to 30 years between refueling, its not a lot to ask technically if we just had the real need to do so. And that will always be a political and business decision, not a technical one.Best, Paul M.
those mission parameters presupposed electrical power from solar panels? I guess that some good fission or fusion reactors (whenever fusion is available) would allow the addition of even more EM Drives and cut that mission time several times.
Quote from: Notsosureofit on 02/19/2015 08:37 pmQuote from: Rodal on 02/19/2015 08:25 pmQuote from: Mulletron on 02/19/2015 08:09 pmI guess not everyone realizes that a resonant cavity can be represented as an LC circuit. They're all the same thing. It can be represented by a simple LC circuit only for simple uniform cavities, with uniform cross-sections, as for example the rectangular cross section cavity or the cylindrical cavity. The truncated cone (frustum) shape used by NASA, Shawyer in the UK and Prof. Juan Yang in China displays degenerate modes that go from resonant to evanescent, and it displays modes that do not conform to the same TEmnp or TMmnp designation as in cylindrical cavities. Actually in reviewing the mode shapes assigned in the COMSOL study for NASA I am now reviewing some interesting cases (the frequencies and images computed by COMSOL are excellent, but the designation of some of the modes is not straightforward, as the NASA engineer realized when designating some of the modes as "X").There is some flexibility. I remember working on delay lines w/ parameters varying w/ length.That was odd stuff, I wonder if it can make a resonant circuit that way?I agree, that's why I wrote "It can be represented by a simple LC circuit only". Yes, with a circuit complicated enough we could probably simulate most electromagnetic wave phenomena, just like the few analog computers that still were being used at MIT Labs in the early 1970's to solve differential equations. I remember those . Reconfiguring the analog computer to solve a different equation required actual handwork unlike just writing software for digital computers :-)
Quote from: Rodal on 02/19/2015 08:25 pmQuote from: Mulletron on 02/19/2015 08:09 pmI guess not everyone realizes that a resonant cavity can be represented as an LC circuit. They're all the same thing. It can be represented by a simple LC circuit only for simple uniform cavities, with uniform cross-sections, as for example the rectangular cross section cavity or the cylindrical cavity. The truncated cone (frustum) shape used by NASA, Shawyer in the UK and Prof. Juan Yang in China displays degenerate modes that go from resonant to evanescent, and it displays modes that do not conform to the same TEmnp or TMmnp designation as in cylindrical cavities. Actually in reviewing the mode shapes assigned in the COMSOL study for NASA I am now reviewing some interesting cases (the frequencies and images computed by COMSOL are excellent, but the designation of some of the modes is not straightforward, as the NASA engineer realized when designating some of the modes as "X").There is some flexibility. I remember working on delay lines w/ parameters varying w/ length.That was odd stuff, I wonder if it can make a resonant circuit that way?
Quote from: Mulletron on 02/19/2015 08:09 pmI guess not everyone realizes that a resonant cavity can be represented as an LC circuit. They're all the same thing. It can be represented by a simple LC circuit only for simple uniform cavities, with uniform cross-sections, as for example the rectangular cross section cavity or the cylindrical cavity. The truncated cone (frustum) shape used by NASA, Shawyer in the UK and Prof. Juan Yang in China displays degenerate modes that go from resonant to evanescent, and it displays modes that do not conform to the same TEmnp or TMmnp designation as in cylindrical cavities. Actually in reviewing the mode shapes assigned in the COMSOL study for NASA I am now reviewing some interesting cases (the frequencies and images computed by COMSOL are excellent, but the designation of some of the modes is not straightforward, as the NASA engineer realized when designating some of the modes as "X").
I guess not everyone realizes that a resonant cavity can be represented as an LC circuit. They're all the same thing.
I wonder if the cavity itself could be used as part of the oscillator using a Gunn diode: http://en.wikipedia.org/wiki/Gunn_diodeThe resulting device would be incredibly compact and self contained, tuning would be inherently a non-issue.
...But unlike all the conventional electric space propulsion concepts(1) propellantless schemes have a potential for practical unlimited power generation as soon as around tpr = 1N/kWe is proven, by mounting driver(s) on a rotor linked to a generator of efficiency n and having a tangential speed above 1/(n * tpr). See attached picture. The only caveat I see would be if wakes of successive passages at same place would interfere and lower the effective thrust power ratio below over-unit cycle. Even in this case I don't see how an over-unit power generating system would still be impossible : use a larger rotor (tethered... many km apart if needed) to give more time for hypothetical wakes to dissipate, use a linear scheme...So, assuming better than 1N/kW can be reached, why bother with conventional energy generators ? Because we would want to convince ourselves that this is not breaking energy conservation and avoid the "free energy" tag ? But it is not "worse" to posit apparent cheap energy than to posit apparent cheap momentum, and from an engineering point of view it makes no sense to use the later and refusing to see the possibility to use the former.Sorry, this is a repost, for details : http://forum.nasaspaceflight.com/index.php?topic=29276.msg1284676#msg1284676(1) except electrodynamic tether used as generator, but at the cost of absorbed deltaV : that is a 0 sum game...
I think this explains how Emdrive can never go over unity.http://usersguidetotheuniverse.com/?p=2865
In the case of the EM Drive, to answer the "overunity" question one has to perform a complete analysis of the whole system. This cannot be done in isolation, without a theory of operation for the EM Drive. It would be like arguing that a windmill or a sailing boat cannot move (in an analysis ignoring the wind) because it would be a source of practical unlimited power. Same thing with extracting energy from the ocean. In the case of the EM Drive, due consideration of the total system is required: whether coupling with the Quantum Vacuum, or coupling with any other external field.
Quote from: Rodal on 02/20/2015 12:04 pmIn the case of the EM Drive, to answer the "overunity" question one has to perform a complete analysis of the whole system. This cannot be done in isolation, without a theory of operation for the EM Drive. It would be like arguing that a windmill or a sailing boat cannot move (in an analysis ignoring the wind) because it would be a source of practical unlimited power. Same thing with extracting energy from the ocean. In the case of the EM Drive, due consideration of the total system is required: whether coupling with the Quantum Vacuum, or coupling with any other external field. Exactly, so we can't rule out the possibility of apparent energy overunity before (the reality of the effect is proven beyond any doubt and) there is a working theory than can encompass the "total system". But the point is, even before we have such working theory that would show how both energy and momentum conservation are guaranteed, we have an experimental/phenomenological prediction of a given thrust/power in a (Lorentz invariant) vacuum, if this is to hold for propulsion (and giving a ship more kinetic energy than spent electric power) then this is to hold for energy generation, regardless of the deeper theories.I don't mean to sound insistent, but I feel a lot of resistance about that important empirical fact, more for psychological reasons than real scientific logic.
The sciences do not try to explain, they hardly even try to interpret, they mainly make models. By a model is meant a mathematical construct which, with the addition of certain verbal interpretations, describes observed phenomena. The justification of such a mathematical construct is solely and precisely that it is expected to work.
Quote from: Star-Drive on 02/20/2015 03:24 amQuote from: aceshigh on 02/19/2015 07:07 pmthose mission parameters presupposed electrical power from solar panels? I guess that some good fission or fusion reactors (whenever fusion is available) would allow the addition of even more EM Drives and cut that mission time several times. Aceshigh:When it comes to manned solar electric propulsion missions, the largest to date proposed photovoltaic arrays for a human crewed missions are in the 300 kilowatt electric (kW-e) power range. However most of the Q-Thruster solar system based mission analysis we did last year assumed using a U235 fission based reactor with a closed-cycle brayton or rankine thermal to electrical power conversion cycle system in the 1.0-to-2.0 Megawatt electric (MW-e) class output with at least a 10 year lifetime. Now it's true that such a space based nuclear power reactor system has never been fielded, but that was due to a lack of a funded mission for same like sending humans to Mars, but more importantly, the lack of the political will to do so. However building such a space-based closed cycle electrical power reactor is technologically feasible and has been since the 1980s. Now like all naval propulsion system, once you've established the viability of a propulsion technique like the EM-Drive, and have an urgent need to do so, what comes next is developing the long lead items needed to power it. And all these electric space propulsion concepts for deep-space human missions, be they conventional ion, Hall or VASMIR type plasma rocket thrusters, or Q-thruster like space drives, go begging for an already developed nuclear power plant that is sized from 1.0 MWe up to 100 MWe output dependent on the mission scenario. I know that this sounds like a lot of power to the space community, but when it's compared to what the US Navy already builds for its nuclear submarine fleet like its "Boomer' Ohio class ICBM vehicles, which sport the 220 MW-thermal (MW-t) S8G reactor that fits in a 42 foot diameter by 55 feet long container and lasts for up to 30 years between refueling, its not a lot to ask technically if we just had the real need to do so. And that will always be a political and business decision, not a technical one.Best, Paul M.S8G weight 2750 tons?BiiiiiiiiiiiigFR needed.
Ok, For those of us who have become completely lost in the math, can you, in layman's terms, explain what everyone seems to SUSPECT is going on when it comes to converting electrical current into motive force? I've tried to follow the math, but was lost a while back, and the best I can understand is that somehow it involves Vaccume Energy and possibley Dark Matter
Quote from: JasonAW3 on 02/20/2015 01:54 pmOk, For those of us who have become completely lost in the math, can you, in layman's terms, explain what everyone seems to SUSPECT is going on when it comes to converting electrical current into motive force? I've tried to follow the math, but was lost a while back, and the best I can understand is that somehow it involves Vaccume Energy and possibley Dark MatterMuch of the work in this thread has not been focused on theories of operation. Most of the recent math has been focused on attempts to amplify the observed effect, for the sake of demonstrating that it is a real effect, rather than experimental artifact.There is not a consensus on the cause of the apparent thrust, be it real or imaginary. Suggestions for causes of real thrust include interactions with dark matter, harnessing linear momentum from the quantum vacuum, evanescent waves creating inertial moments, tapping into photons being the source of momentum in the universe in general... there's a lot of ideas out there. What all of these theories are short on is experimental data. Because there is no money (Eagleworks is not allowed to accept crowd funding), right now is the time to think.
Quote from: lele on 02/20/2015 02:34 pmAssuming that the EM Drive effectively work, it means you are somehow "stealing" energy from somewhere, and that you can create something which looks like perpetual motion. Let's say that the "somewhere" is the quantum void (QV). Since it can't have an infinite energy, it must mean that you can somehow deplete QV energy.I'm not a specialist, but I think the question "What is the value of the vacuum energy of free space?" becomes relevant here. Additionally it raises disturbing (for me at least) questions, like "What happens when QV energy is depleted?".I don't think you are looking at it correctly. Are you stealing from the earth's gravity when you do a push-up? Of course not.
Assuming that the EM Drive effectively work, it means you are somehow "stealing" energy from somewhere, and that you can create something which looks like perpetual motion. Let's say that the "somewhere" is the quantum void (QV). Since it can't have an infinite energy, it must mean that you can somehow deplete QV energy.I'm not a specialist, but I think the question "What is the value of the vacuum energy of free space?" becomes relevant here. Additionally it raises disturbing (for me at least) questions, like "What happens when QV energy is depleted?".