Quote from: inquisitive-j on 06/15/2015 03:10 PMQuote from: kdhilliard on 06/15/2015 03:02 PMHas anyone from Eagleworks other than Paul March (NSF user Star-Drive) posted here?All his posts can be seen here. His last post was on 2015-04-30, the day after NSF's Evaluating NASA’s Futuristic EM Drive feature article was published.~KirkEdit: TypoI'm not sure. Paul March was the person I had in mind the most when I was posting that. I didn't think to look at his profile for a complete list of posts. I also didn't realize that he posted so little outside of emDrive discussion. I was hoping that he had posted in the 2-3 months that I'd been away from the threads, but I suppose not.Can check his stats here:http://forum.nasaspaceflight.com/index.php?action=profile;area=summary;u=2074Was last loggged on 15 June, so he does read forum posts.

Quote from: kdhilliard on 06/15/2015 03:02 PMHas anyone from Eagleworks other than Paul March (NSF user Star-Drive) posted here?All his posts can be seen here. His last post was on 2015-04-30, the day after NSF's Evaluating NASA’s Futuristic EM Drive feature article was published.~KirkEdit: TypoI'm not sure. Paul March was the person I had in mind the most when I was posting that. I didn't think to look at his profile for a complete list of posts. I also didn't realize that he posted so little outside of emDrive discussion. I was hoping that he had posted in the 2-3 months that I'd been away from the threads, but I suppose not.

Has anyone from Eagleworks other than Paul March (NSF user Star-Drive) posted here?All his posts can be seen here. His last post was on 2015-04-30, the day after NSF's Evaluating NASA’s Futuristic EM Drive feature article was published.~KirkEdit: Typo

Quote from: aero on 06/15/2015 03:23 AMWith all the fooling I've done with meep recently, I discovered a new trick. I can show different views of slices of a 4-D data set. Here is the closed cavity with the Gaussian drive frequency centered at 2.253 GHz though Meep/Harminv says it resonates at 2.343 GHz. These are all at timestep 1420. What mode is this illustrated.Shown are big end, center and small end slices "x", and y and z axial slices.What is the reason for the elliptical shape of the electromagnetic field in the circular cross-section views?The boundary conditions should be perfectly circular for a truncated cone. Therefore one expects a circularly symmetric electromagnetic field instead of this surprising elliptical electromagnetic field.There appears to be an asymmetry in the circular cross section of your model responsible for this ellipse.What feature of the model does the major and minor axes of the ellipse align with?They seem to align with the cut-outs your model has at 0 , 90, 180 and 270 degrees.What is the asymmetry responsible for the major axis of the ellipse aligning itself with the cut-outs at 0 and 180 degrees instead of 90 and 270 degrees ?Or, in other words, why should there be an ellipse instead of a rhombus-like shape with symmetry every 90 degrees (the angle between the cut-outs) instead of every 180 degrees?

With all the fooling I've done with meep recently, I discovered a new trick. I can show different views of slices of a 4-D data set. Here is the closed cavity with the Gaussian drive frequency centered at 2.253 GHz though Meep/Harminv says it resonates at 2.343 GHz. These are all at timestep 1420. What mode is this illustrated.Shown are big end, center and small end slices "x", and y and z axial slices.

Quote from: Rodal on 06/15/2015 02:37 PMQuote from: TheTraveller on 06/15/2015 02:28 PMQuote from: Rodal on 06/15/2015 12:38 PM.....I calculated the natural frequency of the EM Drive based on the formula for a perfect cylinder ( https://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity ) (using the cylindrical Bessel functions that you use in your spreadsheet), based on the Mean diameter (the average of the small and big diameters of the Baby EM Drive), I obtained the following frequency for TE013 for perfectly flat ends:24.41 GHzwhich compares to the value I obtained using my exact solution:24.34 GHz......With respect that is not now effective guide wavelength is calculated. Roger Shawyer told me how to do it and I shared this here several times. It is in my SS.The effective guide wavelength is not based on the average of the 2 end plate diameter. It is the numerically integrated value of 10,000 diameters (well I use 10,000, could be more, could be less) including and in between the plates.For the Baby EMD the guide wavelength for the mean/average diameter is = 0.016501. The numerically integrated effective guide wavelength is = 0.018224, which is why your resonance is too high as your effective guide wavelength is too small.Have attached the latest version of the SS, which has a new feature.Let's agree to disagree on this point otherwise this is going to run for ever. You calculate the effective guide wavelength and the cut-off based on Bessel cylinder functions that do not satisfy the boundary conditions of the problem. It is an ad-hoc solution that you like because it agrees with Shawyer's formulation .My point was that there is no justification to include so many digits of numerical precision based on an ad-hoc formula based on cylinder functions and geometrical dimensions (runout, concentricity) of unknown precision, and not performing a spectrum solution, as the participation of other modes in the response is not taken into account (the response of any system will not be the response of a single mode, but will include other mode shapes as well).It is not what I like or not. It is now Roger Shawyer instructed me to calculate the effective guide wavelength.It is your method which does not agree with how Roger Shawyer and SPR do the effective guide wavelength calculation.

Quote from: TheTraveller on 06/15/2015 02:28 PMQuote from: Rodal on 06/15/2015 12:38 PM.....I calculated the natural frequency of the EM Drive based on the formula for a perfect cylinder ( https://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity ) (using the cylindrical Bessel functions that you use in your spreadsheet), based on the Mean diameter (the average of the small and big diameters of the Baby EM Drive), I obtained the following frequency for TE013 for perfectly flat ends:24.41 GHzwhich compares to the value I obtained using my exact solution:24.34 GHz......With respect that is not now effective guide wavelength is calculated. Roger Shawyer told me how to do it and I shared this here several times. It is in my SS.The effective guide wavelength is not based on the average of the 2 end plate diameter. It is the numerically integrated value of 10,000 diameters (well I use 10,000, could be more, could be less) including and in between the plates.For the Baby EMD the guide wavelength for the mean/average diameter is = 0.016501. The numerically integrated effective guide wavelength is = 0.018224, which is why your resonance is too high as your effective guide wavelength is too small.Have attached the latest version of the SS, which has a new feature.Let's agree to disagree on this point otherwise this is going to run for ever. You calculate the effective guide wavelength and the cut-off based on Bessel cylinder functions that do not satisfy the boundary conditions of the problem. It is an ad-hoc solution that you like because it agrees with Shawyer's formulation .My point was that there is no justification to include so many digits of numerical precision based on an ad-hoc formula based on cylinder functions and geometrical dimensions (runout, concentricity) of unknown precision, and not performing a spectrum solution, as the participation of other modes in the response is not taken into account (the response of any system will not be the response of a single mode, but will include other mode shapes as well).

Quote from: Rodal on 06/15/2015 12:38 PM.....I calculated the natural frequency of the EM Drive based on the formula for a perfect cylinder ( https://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity ) (using the cylindrical Bessel functions that you use in your spreadsheet), based on the Mean diameter (the average of the small and big diameters of the Baby EM Drive), I obtained the following frequency for TE013 for perfectly flat ends:24.41 GHzwhich compares to the value I obtained using my exact solution:24.34 GHz......With respect that is not now effective guide wavelength is calculated. Roger Shawyer told me how to do it and I shared this here several times. It is in my SS.The effective guide wavelength is not based on the average of the 2 end plate diameter. It is the numerically integrated value of 10,000 diameters (well I use 10,000, could be more, could be less) including and in between the plates.For the Baby EMD the guide wavelength for the mean/average diameter is = 0.016501. The numerically integrated effective guide wavelength is = 0.018224, which is why your resonance is too high as your effective guide wavelength is too small.Have attached the latest version of the SS, which has a new feature.

.....I calculated the natural frequency of the EM Drive based on the formula for a perfect cylinder ( https://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity ) (using the cylindrical Bessel functions that you use in your spreadsheet), based on the Mean diameter (the average of the small and big diameters of the Baby EM Drive), I obtained the following frequency for TE013 for perfectly flat ends:24.41 GHzwhich compares to the value I obtained using my exact solution:24.34 GHz......

As for the elliptical shape, probably due to the antenna being a line, like this.

Quote from: aero on 06/15/2015 03:29 PMAs for the elliptical shape, probably due to the antenna being a line, like this.Is this antenna shape correct? When I first read the @Rodal post showing those elliptical lines of force I thought immediately of antenna.

Hello,I'm new to this forum and want to add to the discussion:Thrust can be achieved by various error sources interacting with the environment as many out here already pointed out. eagleworks and many others used only small input power therefore i propose a test theory which is built on a pressure gradient caused by thermal effects. Explanation:The measured forces are tiny but divided by the projected area in thrust direction it becomes an even smaller pressure needed for thrust. Example for eagleworks tests: Area: 0.0613116 m² Force~0.05mN => Pressure needed=0.815mPa =0.00000008% of ambient pressure. Note that these is such a tiny pressure change that it could still be produced in near vacuum. My theory now is that this tiny pressure difference is caused by uneven heating in near wall regions (p=RT/rho). Other reasons could be vibrations and magnetic fields. This effect should fairly quickly reach a constant thrust. If this theory holds up we should see a correlation between mode shape and thrust. The node shape dictates where heating occurs. All needed to test this is therefore to integrate heat production over the surfaces and add these up with respect to the orientation of said surface since the pressure gradient should be linear to this. It would probably suffice to use the B field on the boundary as an estimate for the heat production. My prediction is that certain frequencies will produce a heating pattern that is more uneven and hence produces more thrust. With all the reference geometries we have we might see a correlation to the data. If the math has already been done i'd like to apologize.

Actually the cross-correlation looks interesting, there is a relatively clear max (magnitude) centered around 0. Interestingly this absolute max is found at a lag of 3 frames (is it 3 minutes ?).

Quote from: D_Dom on 06/15/2015 03:50 PMQuote from: aero on 06/15/2015 03:29 PMAs for the elliptical shape, probably due to the antenna being a line, like this.Is this antenna shape correct? When I first read the @Rodal post showing those elliptical lines of force I thought immediately of antenna.No. EW uses a loop antenna as best I know. I don't yet know how to model a loop antenna so I use a line source placed for Meep to calculate the highest resonance. Of course antenna length, location and direction make a difference.

I just had another thought experiment but I need a couple of solid answers before I can draw conclusions. I am hoping some of you could fill in on this. No weirdo untestable stuff this time.If I understand correctly, there is massive energy flowing through the "nodes" of the standing waves. Now let's say, we could focus those nodes to maybe the diameter of a proton. We then pump one KiloWatt of power into the cavity. The energy density at the nodes would become high.What I don't know is, could the energy density in the nodes become so high that a singularity could form? And in this case because the mass is the result of energy flux (like a lightbulb, switch off power and instantaneously there's darkness, in case of the nodes they fade extremely quickly in energy density), would it be a an actual virtual singularity suitable as a tabletop black hole for experimenting on?

Quote from: PaulF on 06/15/2015 06:18 PMI just had another thought experiment but I need a couple of solid answers before I can draw conclusions. I am hoping some of you could fill in on this. No weirdo untestable stuff this time.If I understand correctly, there is massive energy flowing through the "nodes" of the standing waves. Now let's say, we could focus those nodes to maybe the diameter of a proton. We then pump one KiloWatt of power into the cavity. The energy density at the nodes would become high.What I don't know is, could the energy density in the nodes become so high that a singularity could form? And in this case because the mass is the result of energy flux (like a lightbulb, switch off power and instantaneously there's darkness, in case of the nodes they fade extremely quickly in energy density), would it be a an actual virtual singularity suitable as a tabletop black hole for experimenting on?No.

Quote from: aero on 06/15/2015 04:17 PMQuote from: D_Dom on 06/15/2015 03:50 PMQuote from: aero on 06/15/2015 03:29 PMAs for the elliptical shape, probably due to the antenna being a line, like this.Is this antenna shape correct? When I first read the @Rodal post showing those elliptical lines of force I thought immediately of antenna.No. EW uses a loop antenna as best I know. I don't yet know how to model a loop antenna so I use a line source placed for Meep to calculate the highest resonance. Of course antenna length, location and direction make a difference.Yes, the loop EW seemed to use was a quarter-wavelength loop, horizontal polarization w/the top and bottom frustum plates. This is different from Shawyer, whom I believe used a monopole design at one time, possibly aligned with frustum side walls. Decent loop page here: http://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/qst/1986/06/page33/index.htmlJulian's was a monopole perpendicular to frustum sidewalls, so no one seems to have settled on one particular style. Not sure about our Aachen friends, but might be the same as Julian's.If I seen any effects w/my test, the radiator (antenna) is the first thing I will vary. Starting out w/a Julian style monopole, not an EW loop on the small plate.

Quote from: frobnicat on 06/15/2015 12:18 AMActually the cross-correlation looks interesting, there is a relatively clear max (magnitude) centered around 0. Interestingly this absolute max is found at a lag of 3 frames (is it 3 minutes ?). I've been thinking more about this, we expect the em drive to produce thrust instantly, if there is a delay that means the thrust producing mechanism is most likely related to heat or another means. Because of this lag I'm leaning towards the thrust not being from a novel mechanism. We'll need more data to be sure.

Quote from: Abyss on 06/15/2015 05:38 PMQuote from: frobnicat on 06/15/2015 12:18 AMActually the cross-correlation looks interesting, there is a relatively clear max (magnitude) centered around 0. Interestingly this absolute max is found at a lag of 3 frames (is it 3 minutes ?). I've been thinking more about this, we expect the em drive to produce thrust instantly, if there is a delay that means the thrust producing mechanism is most likely related to heat or another means. Because of this lag I'm leaning towards the thrust not being from a novel mechanism. We'll need more data to be sure.Don't forget, there was a time delay in previous experiments too, at much higher power levels. If it requires a certain stored-energy threshold before any thrust can be achieved, these guys are playing with only mW where others were using Watts. It could take this Baby EM Drive 1000X longer to ramp up to speed, so to speak.Todd

The Power input is the rate of change in work "W". It results in doing work on the field via the Poynting vector, and also -J*E, which is the current density flowing in the frustum conductors. So look at E and look at J and see where it can be maximized.