This is how EagleWorks measures Q:To measure the resonant cavity’s loaded Q-Factor we simply use our Agilent FieldFox Vector Network Analyzer (VNA)’s S11 return loss function to determine the bandwidth of the resonant cavity’s -3.0 db points from the 0.0 dB reference, divide this bandwidth figure by the resonant frequency and then invert that number to get the loaded Q-Factor
In Shawyers Flight Thruster test the reported max thrust achieved was around 170mN. Here and as attached.http://emdrive.com/flightprogramme.htmlThat is approx 17 gf. Is a bit over the weight of 2 x US dollar coins. If I put them in your outstretched palm, could you feel the weight? Sure it is not a kg but the level is significant and not what some mosquito produces when it lands on your arm.Comment away but maybe first do a bit of homework on the reported experimental results from Shawyer and the Chinese.
There should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.
I have an interesting question / thought experiment in need of some input.Suppose we have a perfectly conducting cylinder and we inject microwaves into the side, at the center of the cylinder. Their momentum propagates equally in both directions and the reflections result in standing waves. At one end of the cylinder, there is a thin layer of water sealed behind glass which is transparent to microwaves. At the other end, there is a perfect reflector. Should there be NET thrust now? Energy is being used to heat the water on one side, while the other side is receiving all of the momentum that is reflected from it. The answer is, momentum is NOT conserved in dissipative systems. There should be thrust in proportion to the amount of heat that can be absorbed by the water. It's heat capacity is not infinite so eventually the system becomes polarized, until the water is allowed to cool.@Rodal mentioned making the cavity a one-way street. Another idea would be to make the frustum out of different metals. Having zinc at one end and copper at the other end will form a galvanic cell, but it also forms a crude diode! This makes it more difficult for current to flow in one direction vs the other direction in the frustum, accomplishing that goal. Different metals can also make it more or less dissipative at each end.Todd
Based on what I have learned, blasting away with a wide band magnetron into a low Q cavity may be a good option as it really reduces lost/NO thrust from being constantly off resonance with a high Q cavity.
Quote from: ragingrei on 05/26/2015 10:31 pmThere should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science. Secondly, if someone is trying to capitalize on pseudo-science, I feel scientists have a moral responsibility to inform people who otherwise wouldn't understand the underlying science behind a proposed device. Informing is all we can do, and in the end, if they want to throw their money at some fantasy, then that's their choice.
Quote from: Supergravity on 05/27/2015 05:37 amQuote from: ragingrei on 05/26/2015 10:31 pmThere should seem to be a difference between "the results of this experiment appear to break the laws of physics; therefore I won't pursue it" and "the results of this experiment appear to break the laws of physics; therefore no one ought to pursue it." The former is a simple life choice, while the latter doesn't seem very much in line with the spirit of science.No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science. Secondly, if someone is trying to capitalize on pseudo-science, I feel scientists have a moral responsibility to inform people who otherwise wouldn't understand the underlying science behind a proposed device. Informing is all we can do, and in the end, if they want to throw their money at some fantasy, then that's their choice.As a tax-paying citizen of the U.S., I have a different perspective. I have a problem with our government not allocating at least a small amount of funding to high-risk high-reward scientific endeavors, including such long-shots as the EM Drive. In my experience--and I've been around awhile--those who nicely fit certain areas of research and experimentation into the convenient "pseudo-scientific" basket are either protecting turf or are innately close-minded. This is particularly true when experimental evidence indicates there might be something interesting happening. There are those who will refuse to gaze into the telescope because it simply does not fit their known models. This is just as true today as it was anciently--and the stakes are probably just as high or higher.
No one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science. Quote from: SeeShells on 05/27/2015 07:08 amDid you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.
Did you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know.
Quote from: Supergravity on 05/27/2015 05:37 amNo one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science. Quote from: SeeShells on 05/27/2015 07:08 amDid you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know. Clearly many people are persuaded by the argument from authority on this subject because few have the technical skills required to evaluate the speculative theories proposed for the emdrive data. This is why convincing other posters one way or the other on whether the experimental effect exists is so difficult; the question is less about the data and more about what sources of information we trust.While I am highly skeptical of the thrust data, which seems to suffer from experimental ambiguity and a very low signal-to-noise ratio, personal experience has taught me that the most interesting discoveries in science are rarely found where we expect to see them. Revolutions in science mostly come from serindipity; even if this work shows that efficient propellantless propulsion is a theoretical illusion, it is looking for measurable effects far from where most experimental eyes are focused. Perhaps if those working on the emdrive look intently enough, they will see something nobody expected.
Quote from: Tetrakis on 05/27/2015 07:48 amQuote from: Supergravity on 05/27/2015 05:37 amNo one has a problem with people pursuing this on their own time and dime. The problem arises when they use federal grant money to pursue fringe, pseudo-scientific ideas that is diverting funding away from valid scientific research and practical applications that are actually grounded in science. Quote from: SeeShells on 05/27/2015 07:08 amDid you know Thomas Edison made over 1000 different tries to just make a light bulb? Just saying you know. Clearly many people are persuaded by the argument from authority on this subject because few have the technical skills required to evaluate the speculative theories proposed for the emdrive data. This is why convincing other posters one way or the other on whether the experimental effect exists is so difficult; the question is less about the data and more about what sources of information we trust.While I am highly skeptical of the thrust data, which seems to suffer from experimental ambiguity and a very low signal-to-noise ratio, personal experience has taught me that the most interesting discoveries in science are rarely found where we expect to see them. Revolutions in science mostly come from serindipity; even if this work shows that efficient propellantless propulsion is a theoretical illusion, it is looking for measurable effects far from where most experimental eyes are focused. Perhaps if those working on the emdrive look intently enough, they will see something nobody expected.My view is it may well turn out to be nothing but if we did miss something revolutionary because of institutional inertia then it would be unforgivable.
There was no on-board propellant consumption: http://www.k.u-tokyo.ac.jp/news/20100105press-e.html but Thrust was generated through the explosive expansion of the atmospheric air by microwave energy deposition at the focus of the microwave beam ( the air is heated up to 10,000 degrees Celsius very rapidly. Steady thrust can be generated by repetitively pulsed microwave irradiations.). So, it wouldn't generate that amount of thrust force without atmospheric air .
Fact is, humans are no different from any other kind of animal. They instinctively protect their turf. While being mandatory to do so in free nature, I think this intrinsic behavior tends to generally hinder 'progress' in our complex societies. That in itself does not say whether the hindered 'progress' would improve conditions for the average populace or worsen them. 'Progress' can also mean you're standing on the edge of a cliff and make one more step forward.. . Or you could make 'progress' by further reducing civil rights and freedoms. It's complicated .Relating to the argument about tax payer's money.. let's just appreciate the fact that the U.S. is willing to spend around 600 billion USD each year just for military - all tax payer's money. Could a tiny, tiny fraction of that insane amount of money be better spent on things like infrastructure, education and health? I think so. But I'm no american tax payer.. so what do I know :p . Maybe using a couple 10k USD for EM-drive research is too much for the poor tax payer, who already has to pony up ~600 billion USD each year for military. Oh well. Priorities.