Quote from: DrBagelBites on 06/26/2015 01:16 amQuote from: rfmwguy on 06/26/2015 01:04 amI saw that in your information. I used traveller's spreadsheet, which is the only working spreadsheet publicly released, (many thanks Mr T.) and it came up with 185 mg of gram-force with a Q of 50K. Not expecting to see that type of Q, I scaled it back to 10K. Plug some numbers into the spreadsheet and see where gram force comes out. Your numbers would be far too small for EMDIYers to validate. Let me know.That is the problem I have been having. My calculated values, by using experimental data found on the emdrive wiki, are far to small to be measured by the EMDIYer. So, I am a bit stuck on what to expect.I don't have that kind of space to create what you have, so I have to figure out a smaller way of testing this thing.If I achieve null results using the shawer inspired spreadsheet, then I would conclude his position is irrelevant. Reason I chose to follow it was its the only public tool I am aware of and its within a diyers measurement capability. Should nasa cough up a designers tool, which I highly doubt, I would consider it provided it doesn't require NIST to test the results.
Quote from: rfmwguy on 06/26/2015 01:04 amI saw that in your information. I used traveller's spreadsheet, which is the only working spreadsheet publicly released, (many thanks Mr T.) and it came up with 185 mg of gram-force with a Q of 50K. Not expecting to see that type of Q, I scaled it back to 10K. Plug some numbers into the spreadsheet and see where gram force comes out. Your numbers would be far too small for EMDIYers to validate. Let me know.That is the problem I have been having. My calculated values, by using experimental data found on the emdrive wiki, are far to small to be measured by the EMDIYer. So, I am a bit stuck on what to expect.I don't have that kind of space to create what you have, so I have to figure out a smaller way of testing this thing.
I saw that in your information. I used traveller's spreadsheet, which is the only working spreadsheet publicly released, (many thanks Mr T.) and it came up with 185 mg of gram-force with a Q of 50K. Not expecting to see that type of Q, I scaled it back to 10K. Plug some numbers into the spreadsheet and see where gram force comes out. Your numbers would be far too small for EMDIYers to validate. Let me know.
Quote from: rfmwguy on 06/26/2015 01:04 amQuote from: DrBagelBites on 06/26/2015 12:52 amQuote from: rfmwguy on 06/26/2015 12:42 am(...)Alright, I have watched the video and your setup looks great! I must have typed it incorrectly, but I was referring to the laser terminus, not actual laser measurement. So, my fault on that. Have you checked for linearity of distance to weight? The NASA test around our power input of 8W is 0.05 mN which is roughly 0.005 mg. So, assuming you have a linear relationship of 2.5 in/200 mg, the hypothetical thrust will cause a rise of about 0.0000625 inches. Is that correct?-II saw that in your information. I used traveller's spreadsheet, which is the only working spreadsheet publicly released, (many thanks Mr T.) and it came up with 185 mg of gram-force with a Q of 50K. Not expecting to see that type of Q, I scaled it back to 10K. Plug some numbers into the spreadsheet and see where gram force comes out. Your numbers would be far too small for EMDIYers to validate. Let me know.Hey Dave,take a gander at this table: http://emdrive.wiki/Experimental_Resultsin the rightmost columns labeled Force/PowerInput the numbers from TheTraveller are based on Shawyer's formula: they are (rounding off) 100 to 1,000 times greater than NASA' findings with mode TM212.So, if your Q is 5,000 instead of 50,000 and your force/PowerInput agrees with NASA (as Iulian Berca's did) then your force could be 10,000 (ten thousand times) smaller than what TheTraveller calculated.Such is the disparity between what NASA and Shawyer have reported. That's why many people in this forum have stated that NASA effectively nullified Shawyer's measurements (actually NASA got zero force without a dielectric).
Quote from: DrBagelBites on 06/26/2015 12:52 amQuote from: rfmwguy on 06/26/2015 12:42 am(...)Alright, I have watched the video and your setup looks great! I must have typed it incorrectly, but I was referring to the laser terminus, not actual laser measurement. So, my fault on that. Have you checked for linearity of distance to weight? The NASA test around our power input of 8W is 0.05 mN which is roughly 0.005 mg. So, assuming you have a linear relationship of 2.5 in/200 mg, the hypothetical thrust will cause a rise of about 0.0000625 inches. Is that correct?-II saw that in your information. I used traveller's spreadsheet, which is the only working spreadsheet publicly released, (many thanks Mr T.) and it came up with 185 mg of gram-force with a Q of 50K. Not expecting to see that type of Q, I scaled it back to 10K. Plug some numbers into the spreadsheet and see where gram force comes out. Your numbers would be far too small for EMDIYers to validate. Let me know.
Quote from: rfmwguy on 06/26/2015 12:42 am(...)Alright, I have watched the video and your setup looks great! I must have typed it incorrectly, but I was referring to the laser terminus, not actual laser measurement. So, my fault on that. Have you checked for linearity of distance to weight? The NASA test around our power input of 8W is 0.05 mN which is roughly 0.005 mg. So, assuming you have a linear relationship of 2.5 in/200 mg, the hypothetical thrust will cause a rise of about 0.0000625 inches. Is that correct?-I
(...)
...See my reply to drbagelbites. Shawyers reported results were within reasonable measurement range. ew is working too near measurement noise levels for homeboy here. Consider my build a possible shawyer refutation, not an ew validation. if null, my expense has been low and I had a little build fun in the process...been a few years.
Quote from: SeeShells on 06/26/2015 01:51 amGood information and some sweet basic engineering. I also am going with the fulcrum. I've started to laminate the beam I'm going to use.Took a 100 mile RT today only to find that the very nice piece of copper with perforations sold this morning, they we supposed to hold it for me. grrrr. So I will be finding another supplier.ShellWow! What a build! How long of a beam are you using?-I
Good information and some sweet basic engineering. I also am going with the fulcrum. I've started to laminate the beam I'm going to use.Took a 100 mile RT today only to find that the very nice piece of copper with perforations sold this morning, they we supposed to hold it for me. grrrr. So I will be finding another supplier.Shell
Quote from: rfmwguy on 06/26/2015 02:15 am...See my reply to drbagelbites. Shawyers reported results were within reasonable measurement range. ew is working too near measurement noise levels for homeboy here. Consider my build a possible shawyer refutation, not an ew validation. if null, my expense has been low and I had a little build fun in the process...been a few years.You have plans for a different setup if null?And agreed, building is the best part regardless if it works.
Something that at least @frobnicat will appreciate - can we build an overunity device (free energy, perpetual motion, you know the drill) with the current crop of EmDrives?The answer is - maybe, but not on Earth; only in space.A generous k-value looks like about 2*10-4 N/W.That corresponds to a breakeven velocity of 10 Km/s.That's a problem for a terrestrial rotator, I think. No - actually I know it is But in space we can make the radius arm as big as we like.Let's say that we can engineer a complete EmDrive system to withstand 100 gee.Then the breakeven radius is 100 Km.That's pushing it, but not completely beyond the bounds of possibility.The hub would be anchored at a mountain top on the Moon and the plane of rotation would be horizontal.
@Rodal,Thanks for the correct dimensions. Using the 9.00 inch length, and narrowing the search bandwidth, Harminv calculates the resonant frequency to be 2.45163893E+009 which seems pretty close. Of course it helps to start with the solution.I started with the search bandwidth = 0.1*drive frequency (your exact solution, 2.45032 GHz), got resonance at 2.45475327E+009, plugged that frequency back in with BW = 0.05, got 2.45163969E+009 Hz, then BW=0.04 gives 2.45163893E+009 Hz. This was with the "magnetic" antenna configured and located half wavelength from the small end.I tried increasing the resolution but that doesn't seem to be the way to use Harminv. After 5 hr. 20 min at double the resolution, Harminv returned nothing. Counter intuitively, reducing the bandwidth increases the run time almost as much as increasing the resolution. Anyway, if I'm reading your data correctly, that is a kind of verification of Harminv's capability to locate resonant frequency accurately in 3D. Now all I need to know is the answer and Harminv will converge to it. Oh, and the Q was extremely high, in the millions using the copper model for the cavity, Now do I understand you that rfmwguy will use 10.2 inch length (TE013) instead of the 9 inch length (TM212)? That does seem like a good choice IMO.
The laser pointer does not have to be aimed directly at a white wall, you can bounce the light off a mirror or 3.
For the DIYTake a look at the following paper, it seems to me that you could improve the Q factor by cooling the end of the cone.A high quality, efficiently coupled microwave cavity for trapping cold moleculeshttp://iopscience.iop.org/0953-4075/48/4/045001/article"The Q-factor was measured as the cavity warmed up from 77 K to room temperature"
it is sad that @thetraveller has disappeared. I would have much appreciated some clarifications on the nature of the "new" paper. If there are no replies, it seems to me that he/she will lose any credibility left.
Quote from: OttO on 06/26/2015 11:34 amFor the DIYTake a look at the following paper, it seems to me that you could improve the Q factor by cooling the end of the cone.A high quality, efficiently coupled microwave cavity for trapping cold moleculeshttp://iopscience.iop.org/0953-4075/48/4/045001/article"The Q-factor was measured as the cavity warmed up from 77 K to room temperature"It looks like that cavity solution can be "split" into two with the center division being a planar surface. The walls in this case are not conical. It would be interesting to see the rest of the mode structure in that case.
Quote from: francesco nicoli on 06/26/2015 11:55 amit is sad that @thetraveller has disappeared. I would have much appreciated some clarifications on the nature of the "new" paper. If there are no replies, it seems to me that he/she will lose any credibility left.Francesco,This is the problem with communications when people don't use their real names to indulge in promotion, claiming that they have special connections, that they are "in the know", "they know more and have better information", that they have special access to unpublished reports and unaccessible information and special influence, discussing "dark programs" and behavior in an Internet forum that they would be more careful to indulge in if they were using their real names: they can always come back under another monicker, since nobody knows who they really are when using monickers.There is no real credibility issue, because credibility is attached to a monicker instead of to a real name. All they have to do is to change their monicker. This is a great difference between communications in real life and communications in a forum.JR