Quote from: Rodal on 07/17/2015 12:22 amI need some data:1) Dimensions of your model: (all in meters) I think it is the RFMWGUY model at 2.45 GHz excitation frequencyDbig=Dsmall=Length =(set! bigdia 11.01) ; ID - inches(set! smalldia 6.25) ; ID - inches(set! high 10.2) ; length - inchesSource: https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37642.0;attach=1042821So, using your notation and SI units:Dbig= 0.279654 metersDsmall= 0.15875 metersLength = 0.25908 meters----------------------------------------------------------------Note to aero: maybe it would be a good idea to define the .ctl model entirely in SI units, from the very start, instead of converting it all later. What do you think?
I need some data:1) Dimensions of your model: (all in meters) I think it is the RFMWGUY model at 2.45 GHz excitation frequencyDbig=Dsmall=Length =
NSF-1701 update...good news for meepers, I have not yet placed the magnetron into the frustum. I will this weekend, so here's ur chance to suggest placement. Suggest wavelength placement and locale...near big, near small or centered. I was planning on 1/2 wavelength from small end...doesn't matter to me. Julian moved from large end to center...meepers can respond.
Quote from: rfmwguy on 07/17/2015 03:03 amNSF-1701 update...good news for meepers, I have not yet placed the magnetron into the frustum. I will this weekend, so here's ur chance to suggest placement. Suggest wavelength placement and locale...near big, near small or centered. I was planning on 1/2 wavelength from small end...doesn't matter to me. Julian moved from large end to center...meepers can respond.Based on the Wolfram Mathematica analysis of the Meep model, the antenna RF feed should be close to the small end, in the location that aero modeled (aero to respond as to exact location).According to this model, the antenna at the big end is a no-no. Bad, because it equalizes the pressure distribution at both ends.
Quote from: rfmwguy on 07/17/2015 03:03 amNSF-1701 update...good news for meepers, I have not yet placed the magnetron into the frustum. I will this weekend, so here's ur chance to suggest placement. Suggest wavelength placement and locale...near big, near small or centered. I was planning on 1/2 wavelength from small end...doesn't matter to me. Julian moved from large end to center...meepers can respond.http://electronicdesign.com/wireless/what-s-difference-between-dipole-and-ground-plane-antennaFigures 3 and 4 treat the small endplate as the ground plane horizontal to the plate,<4. This is the vertical radiation pattern showing elevation of signal from a horizontal dipole one half wavelength above the ground.>Based on the Wolfram Mathematica analysis of the Meep model, the antenna RF feed should be close to the small end, in the location that aero modeled (aero to respond as to exact location).According to this model, the antenna at the big end is a no-no. Bad, because it equalizes the pressure distribution at both ends.
The easiest install will be a centered insert on the small diameter. Antenna is monopole. Small end would be ground plane. Can also locate on frustum side near small end. Question would be does center insertion on small plate disrupt anticipated vectors...hmmm
Quote from: rfmwguy on 07/17/2015 04:20 amThe easiest install will be a centered insert on the small diameter. Antenna is monopole. Small end would be ground plane. Can also locate on frustum side near small end. Question would be does center insertion on small plate disrupt anticipated vectors...hmmmWhat would you do for an antenna if you wanted to setup an circular Bessel function standing wave with near zero group velocity, at the smallest diameter of the frustum? Would you use a monopole or a loop? I think for the TM modes, it needs to use a monopole and for TE modes, it would need to be a loop. Is that correct? And I think it would need to be centered at the small end, just as you said.Maybe we should also model the best way to setup a standing wave for the small diameter dimension, rather than in the length dimension, by modeling a straight cylinder waveguide and find the antenna configuration & location, that has the lowest group velocity and least distortion. Then taper the cavity from there. Just a thought.Todd
So? Where should I send this E-Mail? What should be written inside?
According to present data, testing the EMDrive with input powers at or above 1 MW is necessary to reach a thrust that can actually be experienced without doubt of measurement errors. Achieving a thrust level high enough to lift an object would (as done by Goddard with chemical rockets) finally convince people to adequately fund R&D in this area.Let us gather enough supporters to send an E-Mail to Mythbusters.They definitely have the money and means to use a Gyrotron, Klystron or a similar powerful microwave source and build a simple truncated cone microwave resonator to see whether they can achieve a level of thrust high enough to convince people to fund adequate R&D in this area.
Quote from: DaCunha on 07/17/2015 06:39 amAccording to present data, testing the EMDrive with input powers at or above 1 MW is necessary to reach a thrust that can actually be experienced without doubt of measurement errors. Achieving a thrust level high enough to lift an object would (as done by Goddard with chemical rockets) finally convince people to adequately fund R&D in this area.Let us gather enough supporters to send an E-Mail to Mythbusters.They definitely have the money and means to use a Gyrotron, Klystron or a similar powerful microwave source and build a simple truncated cone microwave resonator to see whether they can achieve a level of thrust high enough to convince people to fund adequate R&D in this area.You do not need that kind of power to have convincing application for the EMdrive. All depends on the type of application you're projecting. A weak but working EMdrive would have a tremendous impact already on the space industry as orbital position thrusters. A huge fuel saver !If , fe, one of the DIY devices would be able to replicate prof Yang's results, in the order of 72gf, that on itself would be a real, usable result..If however you want to achieve the rather inflated claims of EMdrives lifting tons and traveling to the nearest star system in 11years, then yes you'll need a lot more of power. But , let's be honest, those are claims made on paper and are not based upon a real world EMdrive. What scales nicely on paper almost never scales like that in the real world...BUT...Let's just concentrate first on getting clear and unambiguous results so that the EMdrive can gain credibility. If it cant, well.... then it has been an interesting reading on the forum here and a fun hoax to spend our time on...
I like the idea because I actually think THAT the EMDrive IS a myth. And nothing else.And it definitely should be the matter of Mythbusters and not of serious scientists.
Quote from: Jeff131 on 07/17/2015 08:35 amI like the idea because I actually think THAT the EMDrive IS a myth. And nothing else.And it definitely should be the matter of Mythbusters and not of serious scientists.I disagree. From the independent scientific level Dr. Rodal and the others here are actually very sceptic about the EmDrive. Still their research based on rigorous work is starting to show that there may be something into it. You have to understand that even after the years of claims that EmDrive works (claimed by Mr. Shawyer) the true research begun only just now ( from the time NASA EW and chinese folks showed their first results).I learned here that too much shouting why it can and why it can not work leads to dead end only and proves nothing.