Thrust To Power DerivationI posted the attached derivation the other day. The only response was an off the cuff remark from @deltaMass. I guess what I'm looking for is some discussion on why this is wrong, or not. The algebra is correct, the interpretation is that as the Xmn "resonant" wave propagates down the expanding waveguide, the gradient enhances the thrust. I estimated using Wolfram Alpha's waveguide simulator (using 2 different size waveguides) that if the wavelength expansion follows the taper, and the frequency is very near the cut-off. The resulting thrust to power is several orders of magnitude greater than a photon rocket, over a short distance. If the waveguide is long, then it all reduces to 1/c at the far end. If there is no taper, it reduces to 1/v_phase. Taper adds a gradient that depends on the direction of the taper. In one direction it attenuates, in the other it accelerates. Let me know what you think.Todd
...Unless I am mistaken, there is only 1 recognized force (besides experimental error) that could account for variance due to orientation in a vacuum: Electromagnetism. Gravity as we understand it is not variable in a 360 degree horizontal rotation...Am I right on this assumption, Doc?
@RodalSmall end cuts for the lateral, small end antenna are here- Go all the way to the bottom, it is a large file and Google takes some time to load it. The big end cuts are at the top, the y-z views are in the middle and the small end cuts are at the bottom. No, I can't guarantee that the lattice is the same for this data as it is for more recent data. The image files, views, are still valid for what it's worth.https://drive.google.com/file/d/0B1XizxEfB23taGRGU1ozYUNuYTg/view?usp=sharingThat is my recollection. However it is confusing and perhaps not complete WRT the data I have been generating recently for your use. I suggest that if you can't quickly make sense of the data, that I remove the existing file named csv data in the Yang-Shell folder and regenerate data to your latest requirements for both big end lateral and small end lateral antenna, stored in separate folders. Now that I hopefully have my bash shell file corrected, it should be quick, though I will need to re-run meep to guarantee the same lattice.
Quote from: aero on 07/25/2015 05:50 pm@RodalSmall end cuts for the lateral, small end antenna are here- Go all the way to the bottom, it is a large file and Google takes some time to load it. The big end cuts are at the top, the y-z views are in the middle and the small end cuts are at the bottom. No, I can't guarantee that the lattice is the same for this data as it is for more recent data. The image files, views, are still valid for what it's worth.https://drive.google.com/file/d/0B1XizxEfB23taGRGU1ozYUNuYTg/view?usp=sharingThat is my recollection. However it is confusing and perhaps not complete WRT the data I have been generating recently for your use. I suggest that if you can't quickly make sense of the data, that I remove the existing file named csv data in the Yang-Shell folder and regenerate data to your latest requirements for both big end lateral and small end lateral antenna, stored in separate folders. Now that I hopefully have my bash shell file corrected, it should be quick, though I will need to re-run meep to guarantee the same lattice.Yeah, I'm sorry: I tried to make sense out of it but it was just too much work to check those files. I'm not sure whether they are right or not. It would be very helpful if you could rerun and label the files as you did with the more recent ones: B for big end, S for small end, etc. Your latest labeling is very good and intuitive.
Quote from: Notsosureofit on 07/25/2015 03:34 pmQuote from: RonM on 07/25/2015 03:15 pmI agree. By accepted theory, there should be no thrust whatsoever beyond a photon rocket. If there really is verifiable excess thrust, no matter how small, then this a breakthrough.If by accepted theory you include General Relativity, then there should be a small thrust as long as you can accept some deviation from perfectly "flat" space. (the swimming spaceman was a good example)Good point, but I believe conventional wisdom is that space is flat. Of course, conventional wisdom could be wrong. If space isn't perfectly flat, then maybe we are on to something that would make a good drive for spaceflight. Still, no flying cars.
Quote from: RonM on 07/25/2015 03:15 pmI agree. By accepted theory, there should be no thrust whatsoever beyond a photon rocket. If there really is verifiable excess thrust, no matter how small, then this a breakthrough.If by accepted theory you include General Relativity, then there should be a small thrust as long as you can accept some deviation from perfectly "flat" space. (the swimming spaceman was a good example)
I agree. By accepted theory, there should be no thrust whatsoever beyond a photon rocket. If there really is verifiable excess thrust, no matter how small, then this a breakthrough.
Quote from: RonM on 07/25/2015 03:48 pmQuote from: Notsosureofit on 07/25/2015 03:34 pmQuote from: RonM on 07/25/2015 03:15 pmI agree. By accepted theory, there should be no thrust whatsoever beyond a photon rocket. If there really is verifiable excess thrust, no matter how small, then this a breakthrough.If by accepted theory you include General Relativity, then there should be a small thrust as long as you can accept some deviation from perfectly "flat" space. (the swimming spaceman was a good example)Good point, but I believe conventional wisdom is that space is flat. Of course, conventional wisdom could be wrong. If space isn't perfectly flat, then maybe we are on to something that would make a good drive for spaceflight. Still, no flying cars. space time is only flat where there is no gravity. This is why light follows a curved path in the presence of a gravitational well. http://www.math.brown.edu/~banchoff/STG/ma8/papers/dstanke/Project/curved_space.htmlIf you can artificially engineer a gravitational well of sorts, "maybe not exactly gravity but mimic it at a specific frequency", then you might be able to effectively curve space and time/energy at that particular wavelength.
I'm concerned with the headline "EmDrive could reach Pluto in 18 months" being so at odds with what I heard was Prof. Tajmar's experimental data he had obtained a couple of months ago:
Just a heads up you guys dont have to wait till tuesday to get tajmar's paper. its availabe from AIAA's archive for 25 bucks. Working my way through it and his other papers....
Quote from: rfmwguy on 07/25/2015 05:46 pm...Unless I am mistaken, there is only 1 recognized force (besides experimental error) that could account for variance due to orientation in a vacuum: Electromagnetism. Gravity as we understand it is not variable in a 360 degree horizontal rotation...Am I right on this assumption, Doc?Ha, my message is gone puff.You rescued it:Yes, the first thing that comes to mind is electromagnetism, concerning orientation dependence in a horizontal plane, but I think that Sean Carroll and John Baez will use the dependence on orientation as being an experimental artifact arising from the device used to measure the force: they and other skeptics may posit that the measuring device itself was subject to orientation dependence (*) due to purely mechanical reasons and hence that the measured forces are within experimental errors and thus subject to be attacked as noise.(*) Frobnicat has explained orientation dependence problems with a torque balance, for example, arising from the position of the center of mass.
Quote from: dustinthewind on 07/25/2015 06:44 pmQuote from: RonM on 07/25/2015 03:48 pmQuote from: Notsosureofit on 07/25/2015 03:34 pmQuote from: RonM on 07/25/2015 03:15 pmI agree. By accepted theory, there should be no thrust whatsoever beyond a photon rocket. If there really is verifiable excess thrust, no matter how small, then this a breakthrough.If by accepted theory you include General Relativity, then there should be a small thrust as long as you can accept some deviation from perfectly "flat" space. (the swimming spaceman was a good example)Good point, but I believe conventional wisdom is that space is flat. Of course, conventional wisdom could be wrong. If space isn't perfectly flat, then maybe we are on to something that would make a good drive for spaceflight. Still, no flying cars. space time is only flat where there is no gravity. This is why light follows a curved path in the presence of a gravitational well. http://www.math.brown.edu/~banchoff/STG/ma8/papers/dstanke/Project/curved_space.htmlIf you can artificially engineer a gravitational well of sorts, "maybe not exactly gravity but mimic it at a specific frequency", then you might be able to effectively curve space and time/energy at that particular wavelength. Think about what you just said. What "gravity simulation" corresponds to a mirror reflecting light? Did it curve space-time?No, it did not.
Quote from: birchoff on 07/25/2015 06:51 pmJust a heads up you guys dont have to wait till tuesday to get tajmar's paper. its availabe from AIAA's archive for 25 bucks. Working my way through it and his other papers....Excellent! Questions abound, obviously. Good luck digging thru it. While reposting may not be cool until after the presentation, summation is welcomed.
Quote from: Rodal on 07/25/2015 05:54 pmQuote from: rfmwguy on 07/25/2015 05:46 pm...Unless I am mistaken, there is only 1 recognized force (besides experimental error) that could account for variance due to orientation in a vacuum: Electromagnetism. Gravity as we understand it is not variable in a 360 degree horizontal rotation...Am I right on this assumption, Doc?Ha, my message is gone puff.You rescued it:Yes, the first thing that comes to mind is electromagnetism, concerning orientation dependence in a horizontal plane, but I think that Sean Carroll and John Baez will use the dependence on orientation as being an experimental artifact arising from the device used to measure the force: they and other skeptics may posit that the measuring device itself was subject to orientation dependence (*) due to purely mechanical reasons and hence that the measured forces are within experimental errors and thus subject to be attacked as noise.(*) Frobnicat has explained orientation dependence problems with a torque balance, for example, arising from the position of the center of mass.Thanks Doc...very possible test aparatus itself is subject to magnetic orientation. Which begs the question why not rotate the frustum only. May not be possible, but think it would be the logical choice to avoid induced variables.
Quote from: Rodal on 07/25/2015 12:07 pmI'm concerned with the headline "EmDrive could reach Pluto in 18 months" being so at odds with what I heard was Prof. Tajmar's experimental data he had obtained a couple of months ago: Well, it might be that Prof Tajmar's setup had rather a low Q value, but this was not important as his test apparatus went down to sub-micronewton measurement.
Quote from: wembley on 07/25/2015 07:22 pmQuote from: Rodal on 07/25/2015 12:07 pmI'm concerned with the headline "EmDrive could reach Pluto in 18 months" being so at odds with what I heard was Prof. Tajmar's experimental data he had obtained a couple of months ago: Well, it might be that Prof Tajmar's setup had rather a low Q value, but this was not important as his test apparatus went down to sub-micronewton measurement.Did Tajmar ever say that his experimental results can be extrapolated to reach Pluto in 18 months?