QuoteQuoteEM-Drive is not fake science. They have a WORKING prototype and are moving towards a flight test in 2009. www.emdrive.com. This uses actual physics and obeys all the convervation laws.I am NOT impressed by this site. It states that just like a laser ring gyro is a closed system and can measure rotation rate, this drive is a closed system that can produce force. Newton and all have NO problem with a closed system measuring rotation rate. No need to introduce Special Theory effects to explain this. Explaining away the closed system problem by using the laser ring gyro as an analogy tells me these people are incorrect.However I do hope I am wrong and they produce a really nice rocket engine someday. I for one will not be investing my money in this technology.Danny DegerP.S. Maybe there is some change of momentum of the photons that balances the change of momentum of the rocket. This would make the device not violate the law of the conservation of momentum.I took me a while to understand how it works. There is a basic property of a waveguide that describes how the group velocity of a wave changes as the size of the waveguide changes. For the em-drive it is this that creates the force imbalance on the end walls of the cavity. In terms of momentum, if there are two equal masses and the total momentum p=p1-p2 then p is non zero when the velocities of the particle colliding at each end of the waveguide differ. The slope of the walls of the cavity ensure the collisions with the walls along the length result in a nonlinear force ie: the differing group velocities along the length of the sloping cavity ensure the particles don't just bounce around inside the cavity canceling each others forces totally out. One uses the law of relativistic velocity addition to see that there is forward motion when the thruster is viewed by an outside observer (thus an open system).To illustrate:If one fires two opposing canons within a closed box the impact of the canonballs against the walls will cancel out to result in zero motion. If either the velocity or the mass of one of the balls changes en-route to the wall then the impacts will not cancel out and there will be motion. The trick then is to deal with the lost mass or velocity. It has to have gone somewhere. From the point of view of momentum; The em-drive looks at the change in velocity whereas the woodward drive looks at the change in mass. The both deal with the imbalance in different ways. EM-drive uses the properties of waveguides and relativity whereas woodward's drive uses machian mass fluctuations and a rectifier.When one accounts for the energy absorbed into the system to create the motion then one retains conversation of energy. Same for momentum.So I think I understand. Took me a while but I think I'm there. And it is basic physics! It USES newton laws. It just needed a different perspective.
QuoteEM-Drive is not fake science. They have a WORKING prototype and are moving towards a flight test in 2009. www.emdrive.com. This uses actual physics and obeys all the convervation laws.I am NOT impressed by this site. It states that just like a laser ring gyro is a closed system and can measure rotation rate, this drive is a closed system that can produce force. Newton and all have NO problem with a closed system measuring rotation rate. No need to introduce Special Theory effects to explain this. Explaining away the closed system problem by using the laser ring gyro as an analogy tells me these people are incorrect.However I do hope I am wrong and they produce a really nice rocket engine someday. I for one will not be investing my money in this technology.Danny DegerP.S. Maybe there is some change of momentum of the photons that balances the change of momentum of the rocket. This would make the device not violate the law of the conservation of momentum.
EM-Drive is not fake science. They have a WORKING prototype and are moving towards a flight test in 2009. www.emdrive.com. This uses actual physics and obeys all the convervation laws.
Thanks for the explanation. Thrust efficiency is the term I was looking for.A pico-newton is one trillionth of a newton. It may be that the technology will scale as you hypothesise, but that's still a long way to go.Is that level of thrust even enough to tweak a satellite's orbit? And the current state is, roughly, a Carvin amp, at about 20 pounds, some kind of power supply, and some extra circuitry. On the back of the ol' envelope, you'd roughly need a satellite of about 50-100 pounds to just demonstrate this in the real world. I'm sure something could be better modeled in software, but right now, the thrust efficiency is too low.Further, the results haven't been replicated by a different lab, for reasons which sound vague.I've read the article once, and now have blazotron's remarks to assist in my understanding.
"By what mechanism is it reacting against the rest of the universe? Why do other devices not react with the rest of the universe like this? Why is this one special? How can it instantaneously signal the rest of the universe to react? Saying it is so doesn't make it so."You sound like a physicist so let me appeal to you as if you are one.The question you raise is the subject of all of Jim Woodward's theoretical writings found over the years in places like Foundations of Physics. If you're a physicist with a real interest, you'll want to read the papers rather than take the word of a mindless philosopher like myself. You can find some of the papers here:http://physics.fullerton.edu/Woodward.htmlHowever, to answer your question in short: the mechanism you are asking about is the ability to create a Mach Effect (M-E) otherwise known as a "mass fluctuation." Jim's true genius apart from being a wonderfully gifted experimenter, is his bringing Mach's Principle together with Einstein's General Theory of Relativity, in order to show that under very specific conditions, the mass of a material will undergo a temporary fluctuation. What we have is the entire, casually connected universe and its consequent "gravinertial field' as per Mach's Principle, can be used to generate a gravinertial flux into and out of the ceramic in question, causing its mass to fluctuate temporarily.I'm sure that sounds like an outrageous claim to any physicist who has never studied Mach's Principle or read any of Jim Woodward's papers. :-) It's not so outrageous and this was all peer reviewed more than a decade ago.So let me invite you to take a few minutes and read at least one of Jim's papers from over the years.
Folks:Let me clarify a few things that G/I Thruster has said recently. I know of at least nine other attempts at replicating Jim's Woodward mass fluctuation conjecture, his unidirectional force generators (UFG) or the Mach-Lorentz Thruster (MLT) devices. I’ll list them below in the year they were first published:1. Hector Brito’s ~1996 self contained battery operated MLT like device running at ~40 kHz that demonstrated ~1.0 micro-Newton level thrusts based on his E&M Slepian approach to this propellantless thruster business. 2. Andrew Palfreyman’s 1990’s UFG experiment reporting null results.3. Woodward’s 1997-9 graduate student Tom Mahood with his ~50 kHz UFG torque pendulum in a vacuum experiments that demonstrated thrust levels on the order of 0.10 to 1.00 micro-Newton. 4. John Mckeever’s Oak-Ridge lab team’s 2000 MLT replication that reported thrust signatures that were attributed to thermal effects.5. Paul March’s 2004 & 2005 MLT data running at 2.2 and 3.8 MHz reported up to 5.0 milli-Newton results.6. John Cramer’s 2005 thru 2007, 220 Hz Machian Guitar mass fluctuation experiment which resulted in an ambiguous results before their BPP money ran out. 7. Nembo Buldrini’s 2006, 50 kHz and 2.0 MHz ambiguous or null results. 8. John Strader’s 2006, ~400 kHz MLT experiments that reported null results.9. Duncan Cumming’s 2007 self-contained coke can MLT running at ~400 kHz reported null results. 10. Jim Woodward’s latest 2008/2009 M-E rotary proof of principle tests that have clearly demonstrated above the noise 2-omega M-E like mass fluctuations signatures.Looking back over this list I can appreciate why a lot of folks view Woodward’s M-E conjecture in the same light as they do the “Cold Fusion” conjecture, but in a similar way, I believe that Woodward’s M-E conjecture will be validated in a similar manner as the cold fusion story has unfolded over the last twenty years. (See attached CBS 60 Minutes story on the resurrection of cold fusion that aired yesterday (04-19-2009). Why do I think this way? Because of the extreme difficulty in getting the phase relations between the acoustical and electrical drive signals in these M-E based devices to constructively interfere with each other instead of killing each other off. In others words there are thousands of ways to build and operate these devices where they won’t work, but there is only a few ways to build and operate them where they will work. Hector Brito, Tom Mahood and I are the only folks that I know of who happened to luck into the right combination of ingredients to make it play with my and Jim Woodward’s Mach-2MHz MLT experiment providing the largest thrust signatures to date.BTW, Woodward’s lowest vacuum pressure ever achieved in his lab was on the order of ~2x10^-3 Torr and not 1x10^-6 Torr as reported by G/I thruster. Considering that Woodward has never pumped his Plexiglas vacuum chambers with anything more than a standard Welch vacuum roughing pump, that is hardly surprising. However, ~2x10^-3 Torr pressure is quite sufficient to kill off 99.99% of the ion wind issues that could contaminate Woodward’s MLT results, even when his MLTs were only producing a few micro-Newton.
Quote from: Star-Drive on 04/20/2009 08:07 pmFolks:Let me clarify a few things that G/I Thruster has said recently. I know of at least nine other attempts at replicating Jim's Woodward mass fluctuation conjecture, his unidirectional force generators (UFG) or the Mach-Lorentz Thruster (MLT) devices. I’ll list them below in the year they were first published:1. Hector Brito’s ~1996 self contained battery operated MLT like device running at ~40 kHz that demonstrated ~1.0 micro-Newton level thrusts based on his E&M Slepian approach to this propellantless thruster business. 2. Andrew Palfreyman’s 1990’s UFG experiment reporting null results.3. Woodward’s 1997-9 graduate student Tom Mahood with his ~50 kHz UFG torque pendulum in a vacuum experiments that demonstrated thrust levels on the order of 0.10 to 1.00 micro-Newton. 4. John Mckeever’s Oak-Ridge lab team’s 2000 MLT replication that reported thrust signatures that were attributed to thermal effects.5. Paul March’s 2004 & 2005 MLT data running at 2.2 and 3.8 MHz reported up to 5.0 milli-Newton results.6. John Cramer’s 2005 thru 2007, 220 Hz Machian Guitar mass fluctuation experiment which resulted in an ambiguous results before their BPP money ran out. 7. Nembo Buldrini’s 2006, 50 kHz and 2.0 MHz ambiguous or null results. 8. John Strader’s 2006, ~400 kHz MLT experiments that reported null results.9. Duncan Cumming’s 2007 self-contained coke can MLT running at ~400 kHz reported null results. 10. Jim Woodward’s latest 2008/2009 M-E rotary proof of principle tests that have clearly demonstrated above the noise 2-omega M-E like mass fluctuations signatures.Looking back over this list I can appreciate why a lot of folks view Woodward’s M-E conjecture in the same light as they do the “Cold Fusion” conjecture, but in a similar way, I believe that Woodward’s M-E conjecture will be validated in a similar manner as the cold fusion story has unfolded over the last twenty years. (See attached CBS 60 Minutes story on the resurrection of cold fusion that aired yesterday (04-19-2009). Why do I think this way? Because of the extreme difficulty in getting the phase relations between the acoustical and electrical drive signals in these M-E based devices to constructively interfere with each other instead of killing each other off. In others words there are thousands of ways to build and operate these devices where they won’t work, but there is only a few ways to build and operate them where they will work. Hector Brito, Tom Mahood and I are the only folks that I know of who happened to luck into the right combination of ingredients to make it play with my and Jim Woodward’s Mach-2MHz MLT experiment providing the largest thrust signatures to date.BTW, Woodward’s lowest vacuum pressure ever achieved in his lab was on the order of ~2x10^-3 Torr and not 1x10^-6 Torr as reported by G/I thruster. Considering that Woodward has never pumped his Plexiglas vacuum chambers with anything more than a standard Welch vacuum roughing pump, that is hardly surprising. However, ~2x10^-3 Torr pressure is quite sufficient to kill off 99.99% of the ion wind issues that could contaminate Woodward’s MLT results, even when his MLTs were only producing a few micro-Newton. Star-Drive:Thank you for the nice summary of experimental work.I wanted to comment that while 2E-3 Torr may be plenty to kill off most of the ion effects, it places the pressure almost at the peak of the Crookes Radiometer effect:http://en.wikipedia.org/wiki/Crookes_radiometer
"But also about the power requirements. There’s a post above that mentions a Carvin 2kw amp. This thing has got to weigh twenty pounds or more, and be supplied by 110V current, right? Please explain how a 2kw power supply provides only micro-newtons of force. It would seem that an electric motor is more efficient."Em, yeah. An electric motor would be more efficient than the test articles to date if indeed it had something in space to actually push off of--which it would not--which is why till the foreseeable future we're stuck with rockets..(snip).I don't know how many watts Paul March used on his MTL but lets say he used 250. He got 5 mN thrust. If that's so, then the same thruster could be bundled with three others and you'd have 20 mN thrust, the same as the max thrust of the ion thrusters on the GOCE. Now I don't know what the power requirements are for the GOCE thrusters but I do know they require 40 kg of Xenon for a 2 year mission, plus the power system. So if your MLT bundle is anywhere in the ballpark of 40 kg, and the power requirements are anything near the same (1KW), you know that the MLT is competitive with some of the best ion tech out there.Anyone know what GOCE's thrusters require?But again let me state in no uncertain terms that I am NOT SAYING this is a useful comparison. Before we could talk about competing with things like ion, we'd have to solve issues like the ceramic ageing issue and we haven't even begun to look into that yet. We are not working on prototyping. We're working on pure research.
cutting-edge system being flown by ESA.
Quote from: GI-Thruster on 04/21/2009 11:19 pmcutting-edge system being flown by ESA.What cutting-edge system? Ion propulsion is not new.