Quote from: TheTraveller on 05/19/2015 07:20 pmQuote from: squid on 05/19/2015 06:51 pmQuote from: TheTraveller on 05/19/2015 06:30 pmBoth Shawyer & the Chinese claim their many physical devices produce thrust and the measurement of that thrust is in agreement with their theoretical calculations. Both also claim no new physics is needed and CofE / CofM are conserved.I mean you say it can't work as they claim, yet it does and the measured thrust from many devices, measured in different ways, in different labs, in different countries all closely matched what their theory says the thrust should be.With respect, just maybe your explanation / understanding of what is happening inside the frustum is not at the same level as Shawyer or the Chinese?Or perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits? This is all standard physics, supported by a century of experiments all conducted with far more precision and rigor than anything published on the EM drive.Incidentally, after doing a brief literature search, I have attached an experiment performed in the early 90's on a superconducting frustrum cavity, with a Q of at least 20,000. The paper is nice in that it gives explicit formulae for the EM fields in such a cavity. Their classical model fits the data perfectly. I might also note that they didn't see the thing shoot out of their dewar...Guess you have not read the Chinese data:http://www.emdrive.com/NWPU2010translation.pdfhttp://www.emdrive.com/NWPU2010testresults.pdfhttp://www.emdrive.com/yang-juan-paper-2012.pdfThe thrust measured was not the EagleWorks mosquito landing on your arm level. Maybe read the papers before claimingQuoteOr perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?as a quick way to dismiss their results.A.single paper is not a magic wand which causes all previous results to disappear. It cannot chan ge the tens of thousands of previous measure ments that have taken place in the last 50years. How do you refute cavities in pillbox shape that are used in GPS satellite atomic clocks? These have been characterized down to sub nanowatt levels, and no mystery power draw is observed and no thrust is observed in the GPS satellites (the location of which must be known very well.)
Quote from: squid on 05/19/2015 06:51 pmQuote from: TheTraveller on 05/19/2015 06:30 pmBoth Shawyer & the Chinese claim their many physical devices produce thrust and the measurement of that thrust is in agreement with their theoretical calculations. Both also claim no new physics is needed and CofE / CofM are conserved.I mean you say it can't work as they claim, yet it does and the measured thrust from many devices, measured in different ways, in different labs, in different countries all closely matched what their theory says the thrust should be.With respect, just maybe your explanation / understanding of what is happening inside the frustum is not at the same level as Shawyer or the Chinese?Or perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits? This is all standard physics, supported by a century of experiments all conducted with far more precision and rigor than anything published on the EM drive.Incidentally, after doing a brief literature search, I have attached an experiment performed in the early 90's on a superconducting frustrum cavity, with a Q of at least 20,000. The paper is nice in that it gives explicit formulae for the EM fields in such a cavity. Their classical model fits the data perfectly. I might also note that they didn't see the thing shoot out of their dewar...Guess you have not read the Chinese data:http://www.emdrive.com/NWPU2010translation.pdfhttp://www.emdrive.com/NWPU2010testresults.pdfhttp://www.emdrive.com/yang-juan-paper-2012.pdfThe thrust measured was not the EagleWorks mosquito landing on your arm level. Maybe read the papers before claimingQuoteOr perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?as a quick way to dismiss their results.
Quote from: TheTraveller on 05/19/2015 06:30 pmBoth Shawyer & the Chinese claim their many physical devices produce thrust and the measurement of that thrust is in agreement with their theoretical calculations. Both also claim no new physics is needed and CofE / CofM are conserved.I mean you say it can't work as they claim, yet it does and the measured thrust from many devices, measured in different ways, in different labs, in different countries all closely matched what their theory says the thrust should be.With respect, just maybe your explanation / understanding of what is happening inside the frustum is not at the same level as Shawyer or the Chinese?Or perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits? This is all standard physics, supported by a century of experiments all conducted with far more precision and rigor than anything published on the EM drive.Incidentally, after doing a brief literature search, I have attached an experiment performed in the early 90's on a superconducting frustrum cavity, with a Q of at least 20,000. The paper is nice in that it gives explicit formulae for the EM fields in such a cavity. Their classical model fits the data perfectly. I might also note that they didn't see the thing shoot out of their dewar...
Both Shawyer & the Chinese claim their many physical devices produce thrust and the measurement of that thrust is in agreement with their theoretical calculations. Both also claim no new physics is needed and CofE / CofM are conserved.I mean you say it can't work as they claim, yet it does and the measured thrust from many devices, measured in different ways, in different labs, in different countries all closely matched what their theory says the thrust should be.With respect, just maybe your explanation / understanding of what is happening inside the frustum is not at the same level as Shawyer or the Chinese?
Or perhaps they are all making basic mistakes in their sloppy experimental setups, pumping kW of microwave power into poorly shielded cavities and reporting thrusts near their error limits?
Quote from: Stormbringer on 05/19/2015 08:20 pmHow about extrapolating/interpolating downward by calculating dimensions from resonant frequencies of these test articles? Use that interpolation to select a smaller sized set of cavity dimensions and scale up the frequencies to get that thrust signal out of the "iffy" zone?The point I was making was that we don't know whether or not higher frequencies produce higher thrust. That's unless you happen to know.
How about extrapolating/interpolating downward by calculating dimensions from resonant frequencies of these test articles? Use that interpolation to select a smaller sized set of cavity dimensions and scale up the frequencies to get that thrust signal out of the "iffy" zone?
Quote from: SeeShells on 05/19/2015 07:53 pmQuote from: phaseshift on 05/19/2015 07:26 pmQuote from: Rodal on 05/19/2015 06:47 pmQuote from: phaseshift on 05/19/2015 06:40 pmA thought experiment:Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221. I have Warped Passages by Lisa Randall, I need to get it out and re-read it, she is one of my heroes and if I believe (need to look again) she finds quasicrystals might have an underlying structure into other dimensions. Whoa! Ok need to sit in my hot tub and think some.I have all of her books (4 I think, or is it 3?). In Warped Passages I swear I remember her mentioning the possibility of inflating the 4sd (4th spatial dimension) - though there was no known mechanism. Just like there is no known physical mechanism for the inflationary period of the Universe.Knocking on Heaven's Door and another about the Higgs. Think it's 3.It is somewhat light but meant for a specific audience, but she likes the string theory (I always liked it) and if you can write and make sense from our perspective another dimension without higher order math, my hat is off.I keep on associating (several papers and books) again and again to magneto-chiral matter and how it interacts to the Casimir force and momentum, there seems a wonderful link there. "I'M GIVIN' HER ALL SHE'S GOT, CAPTAIN!" Need more brains!
Quote from: phaseshift on 05/19/2015 07:26 pmQuote from: Rodal on 05/19/2015 06:47 pmQuote from: phaseshift on 05/19/2015 06:40 pmA thought experiment:Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221. I have Warped Passages by Lisa Randall, I need to get it out and re-read it, she is one of my heroes and if I believe (need to look again) she finds quasicrystals might have an underlying structure into other dimensions. Whoa! Ok need to sit in my hot tub and think some.I have all of her books (4 I think, or is it 3?). In Warped Passages I swear I remember her mentioning the possibility of inflating the 4sd (4th spatial dimension) - though there was no known mechanism. Just like there is no known physical mechanism for the inflationary period of the Universe.Knocking on Heaven's Door and another about the Higgs. Think it's 3.It is somewhat light but meant for a specific audience, but she likes the string theory (I always liked it) and if you can write and make sense from our perspective another dimension without higher order math, my hat is off.I keep on associating (several papers and books) again and again to magneto-chiral matter and how it interacts to the Casimir force and momentum, there seems a wonderful link there. "I'M GIVIN' HER ALL SHE'S GOT, CAPTAIN!" Need more brains!
Quote from: Rodal on 05/19/2015 06:47 pmQuote from: phaseshift on 05/19/2015 06:40 pmA thought experiment:Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221. I have Warped Passages by Lisa Randall, I need to get it out and re-read it, she is one of my heroes and if I believe (need to look again) she finds quasicrystals might have an underlying structure into other dimensions. Whoa! Ok need to sit in my hot tub and think some.I have all of her books (4 I think, or is it 3?). In Warped Passages I swear I remember her mentioning the possibility of inflating the 4sd (4th spatial dimension) - though there was no known mechanism. Just like there is no known physical mechanism for the inflationary period of the Universe.Knocking on Heaven's Door and another about the Higgs. Think it's 3.It is somewhat light but meant for a specific audience, but she likes the string theory (I always liked it) and if you can write and make sense from our perspective another dimension without higher order math, my hat is off.I keep on associating (several papers and books) again and again to magneto-chiral matter and how it interacts to the Casimir force and momentum, there seems a wonderful link there. "I'M GIVIN' HER ALL SHE'S GOT, CAPTAIN!" Need more brains!
Quote from: phaseshift on 05/19/2015 06:40 pmA thought experiment:Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221. I have Warped Passages by Lisa Randall, I need to get it out and re-read it, she is one of my heroes and if I believe (need to look again) she finds quasicrystals might have an underlying structure into other dimensions. Whoa! Ok need to sit in my hot tub and think some.I have all of her books (4 I think, or is it 3?). In Warped Passages I swear I remember her mentioning the possibility of inflating the 4sd (4th spatial dimension) - though there was no known mechanism. Just like there is no known physical mechanism for the inflationary period of the Universe.
A thought experiment:Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221. I have Warped Passages by Lisa Randall, I need to get it out and re-read it, she is one of my heroes and if I believe (need to look again) she finds quasicrystals might have an underlying structure into other dimensions. Whoa! Ok need to sit in my hot tub and think some.
It should be pointed out that this Shawyer thrust equation1) F = 2 Df Po Q / c has been rejected by the physics community. Their version is2) F = 0.Let's however go with it. Assuming that we do a decent job with Df and so get Df = DfMax = 1. Then the equation predicts that you get 2*Q times the thrust you'd get from a photon rocket of the same power.But since a cavity's Q = w E / P, where w=angular frequency, E=stored energy, P=input power, Shawyer's thrust equation becomes3) F = (2 E/c) wand thus thrust scales linearly with frequency, and linearly with the stored energy.Let's imagine we have a little 150 mW laser diode attached to a resonant cavity, powered by a tiny battery.The whole thing weighs probably about 50 gm (SWAG).That's light enough and small enough to fit on a Mettler H20 balance, an inspired piece of Swiss mechanical engineering that reliably gets you 10 microgram-weight resolution, or 0.1 microNewtons.Equation 1) with Df=1 predicts a thrust of Q/1000 microNewtons.Thus the Mettler should detect thrust for Q > 100.This is usually far exceeded by optical cavities, which can have Qs up in the millions.So this experiment is expected to easily detect thrust from this little device.Indeed, if Q > 5*108, it would lift off the bench when appropriately oriented.If Shawyer is correct, that is.
Let's imagine we have a little 150 mW laser diode attached to a resonant cavity, powered by a tiny battery.The whole thing weighs probably about 50 gm (SWAG)....So this experiment is expected to easily detect thrust from this little device.Indeed, if Q > 5*108, it would lift off the bench when appropriately oriented.If Shawyer is correct, that is.
Quote from: Rodal on 05/19/2015 06:47 pmQuote from: phaseshift on 05/19/2015 06:40 pmA thought experiment:Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221. Briefly they claim an additional finite dimension between our brane (weak/Tev) and a gravity brane (strong) where gravity actually exists. The distance between these branes is the reason that gravity is such a comparatively weak force. The length of this 4th spacial dimension has an upper limit of somewhat less than 1 millimeter (otherwise we would have seen its effects long ago). The force of gravity on the gravity brane is expected to be 16 orders of magnitude greater than it is on our brane....For whatever it's worth, a short note that Dr. White and Paul March both have invoked a (4+1) brane of spacetime in their explanation and papers.Yes, I noticed that. Though I didn't follow why they did so, it seemed disconnected to me. I thought they referred to a 3+1 space, but if they used 4+1 then they included time. I'm more inclined to use 3+1 and set time aside.
Quote from: phaseshift on 05/19/2015 06:40 pmA thought experiment:Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221. Briefly they claim an additional finite dimension between our brane (weak/Tev) and a gravity brane (strong) where gravity actually exists. The distance between these branes is the reason that gravity is such a comparatively weak force. The length of this 4th spacial dimension has an upper limit of somewhat less than 1 millimeter (otherwise we would have seen its effects long ago). The force of gravity on the gravity brane is expected to be 16 orders of magnitude greater than it is on our brane....For whatever it's worth, a short note that Dr. White and Paul March both have invoked a (4+1) brane of spacetime in their explanation and papers.
A thought experiment:Many physicists postulate that we live in a 3+1 deSitter space, and specifically I refer to Lisa Randall, Raman Sundrum http://arxiv.org/abs/hep-ph/9905221. Briefly they claim an additional finite dimension between our brane (weak/Tev) and a gravity brane (strong) where gravity actually exists. The distance between these branes is the reason that gravity is such a comparatively weak force. The length of this 4th spacial dimension has an upper limit of somewhat less than 1 millimeter (otherwise we would have seen its effects long ago). The force of gravity on the gravity brane is expected to be 16 orders of magnitude greater than it is on our brane....
Quote from: deltaMass on 05/19/2015 09:24 pmLet's imagine we have a little 150 mW laser diode attached to a resonant cavity, powered by a tiny battery.The whole thing weighs probably about 50 gm (SWAG)....So this experiment is expected to easily detect thrust from this little device.Indeed, if Q > 5*108, it would lift off the bench when appropriately oriented.If Shawyer is correct, that is.I suspect it is quite difficult to build something with the required properties in laser wavelengths.
...Of course frequency has an effect on thrust. Dumb statement for me to make as I only considered Df in a fixed frustum. Was thinking about my Flight Thruster design simulator, which did have a fixed Q of 50,000 at 3.85GHz but not anymore. Thanks for that input. "Click" another piece of the puzzle drops into place.
Shawyer states that the cavity reflectors must be half a wavelength apart, which might be a bit fiddly at laser frequencies.
Indeed you are correct, because eqn 3 suppresses the possible frequency dependence of E.So let's go with thrust not being frequency dependent. That means that far higher thrust-to-weight ratios can be expected at higher frequencies. And in that vein, I like the idea of a fully self-contained tapered fibre laser.
Indeed you are correct, because eqn 3 suppresses the possible frequency dependence of E.So let's go with thrust not being frequency dependent. That means that far higher thrust-to-weight ratios can be expected at higher frequencies. And in that vein, I like the idea of a fully self-contained tapered fibre laser. It would weigh next to nothing - the battery would be most of the weight.
Quote from: deltaMass on 05/19/2015 09:24 pmIt should be pointed out that this Shawyer thrust equation1) F = 2 Df Po Q / c has been rejected by the physics community. Their version is2) F = 0.Let's however go with it. Assuming that we do a decent job with Df and so get Df = DfMax = 1. Then the equation predicts that you get 2*Q times the thrust you'd get from a photon rocket of the same power.But since a cavity's Q = w E / P, where w=angular frequency, E=stored energy, P=input power, Shawyer's thrust equation becomes3) F = (2 E/c) wand thus thrust scales linearly with frequency, and linearly with the stored energy.Let's imagine we have a little 150 mW laser diode attached to a resonant cavity, powered by a tiny battery.The whole thing weighs probably about 50 gm (SWAG).That's light enough and small enough to fit on a Mettler H20 balance, an inspired piece of Swiss mechanical engineering that reliably gets you 10 microgram-weight resolution, or 0.1 microNewtons.Equation 1) with Df=1 predicts a thrust of Q/1000 microNewtons.Thus the Mettler should detect thrust for Q > 100.This is usually far exceeded by optical cavities, which can have Qs up in the millions.So this experiment is expected to easily detect thrust from this little device.Indeed, if Q > 5*108, it would lift off the bench when appropriately oriented.If Shawyer is correct, that is.More accurately, F = (2 Df Po Q / c) * D, where D is the Duty Cycle of the output. IF it were to put out thrust continuously at this value of F, CoE would be violated, because you are only putting in Po*t, not Q*Po*t. It takes time to store energy, and once it is stored, it can only deliver thrust for a limited amount of time before it needs to be recharged again. So there is a duty cycle associated with this thing that is being ignored.Personally, I do not find Shawyer's equation to be that far off. I agree, his theory is flawed if you consider only perfectly conducting walls and group velocity. But, given asymmetrical losses, his assumption that F2 - F1 > 0 is exactly what it is. Two forces that are not exactly equal, opposing each other. The "how and why" are debatable, but the reality of it is not. Had someone done a Buckingham Pie Theory analysis of this, just based on input variables, the Max. potential thrust, 2*Q*P/c multiplied by an unknown Df based on the geometry, and whose value is to be experimentally determined, is exactly what you should get. Todd D.