-
#1980 by birchoff on 19 Jan, 2016 20:38
-
thanks thats what I thought but wasnt sure. How about all the Meep and now FEKO runs. are any of them being done with a dielectric fixed on the small end?Are their any DIY experiemnts in progress with dielectric's similar to what EW is using?
No, not the same setup, as far as I know SheShells schedules to test thin dielectrics.
(Don't know if this is already in the pipeline.) -
#1981 by Kenjee on 19 Jan, 2016 20:48
-
Don`t forget 70% of time I have no clue what you are talking about.
Other 30% I just think I know
Anyway, like always, this is just an artist rendition of idea. Or not?
Video:
https://vid.me/PCq5
and keep up! -
#1982 by forgravity on 19 Jan, 2016 21:51
-
Noob here,
I was just wondering if the TE mode is fixed based on the dimensions of the frustum or if it can be changed depending on frequency etc.
-
#1983 by Rodal on 19 Jan, 2016 22:14
-
Noob here,
I was just wondering if the TE mode is fixed based on the dimensions of the frustum or if it can be changed depending on frequency etc.
ANSWER: The geometry, the properties of the medium filling the inside of the cavity, as well as three mode shape parameters (m,n and p) determine a unique natural frequency.
_____________________
In more detail:
The mode shapes and natural frequencies both together are associated with each other and they are so-called eigenvalue solutions to the eigenvalue equation. These solutions are a function of the geometry and of the medium properties (the electric permittivity and the magnetic permeability of the air or of the vacuum filling the interior cavity).
See, for example for a cylindrical cavity: https://en.wikipedia.org/wiki/Microwave_cavity#Cylindrical_cavity
so for TE (transverse electric) modes, you have these natural frequencies:
where the so-called "quantum numbers": m,n,p are such that m and p are integers that can be 0,1,2,... (up to infinity) and n needs to be equal or larger than 1: n=1,2,3...(up to infinity). There are always an infinite number of natural frequencies and associated mode shapes.
This table gives the values of X'mn as a function of m and n, for m ranging from 0 to 10 and for n ranging from 1 to 5:
http://wwwal.kuicr.kyoto-u.ac.jp/www/accelerator/a4/besselroot.htmlx
R is the radius of the cylinder
L is the length of the cylinder
c is the speed of light in vacuum
μr is the relative magnetic permeability of the medium filling the cavity
εr is the relative electric permittivity of the medium filling the cavity
For a vacuum, μr = 1 and εr =1
For air, μr = 1.00000037 and εr =1.00058986
For ammonia μr ~ 1 and εr =17
For extruded High Density PolyEthylene at 1-3GHz, μr ~ 1 and εr = 2.26
So you see how a given mode shape, for example TE012 means that m=0, n=1 and p=2, therefore (looking at the table of values) X'01=3.83170597020751, and therefore a mode shape like TE012, and the geometry (R and L) and medium properties (μr and εr ) uniquely determine the frequency of this mode shape TE012
For a truncated cone like the EM Drive, the solution is more complicated than the one for a cylinder, but still a given geometry, together with the medium properties uniquely determine a frequency for fixed values of three parameters .
For a truncated cone like the EM Drive, see for example: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html for the exact solution for the mode shapes and natural frequencies
_____________
EM Drive theories, like the Notsosureofit Hypothesis http://emdrive.wiki/@notsosureofit_Hypothesis predict (everything else being the same) a larger force if the medium inside the EM Drive would have a higher (μr * εr), value. For example, the force should be higher if the medium inside the EM Drive would be ammonia instead of being air (or vacuum) -
#1984 by Rodal on 19 Jan, 2016 22:59
-
thanks thats what I thought but wasnt sure. How about all the Meep and now FEKO runs. are any of them being done with a dielectric fixed on the small end?Are their any DIY experiemnts in progress with dielectric's similar to what EW is using?
No, not the same setup, as far as I know SheShells schedules to test thin dielectrics.
(Don't know if this is already in the pipeline.)
Great question !!!
This is really what these programs are for. Anybody running FEKO (or COMSOL, or ANSYS, etc, etc.) will be able to include a dielectric at ease and readily give you a solution. With Meep...you will have to spend much more effort in making sure that the input is correct, and the mesh etc, and then you will have all the previously mentioned confusion assessing what is the mode shape, and what is going on for a truncated cone unless you do post-process the solution to calculate vector resultants, etc. With FEKO, and the other programs you will get output in SI units that you can relate to. With Meep your output is in Meep dimensionless units and you will have to convert numbers to SI units to know what is going on. (Or be lost and confused if you are given Meep images without any numerical fields). -
#1985 by dustinthewind on 19 Jan, 2016 23:08
-
My initial knee jerk reaction is to say that for the generator to accelerate when spinning that it would be pulling in energy from its surrounding environment. I can't say exactly how it would do so as I don't fully understand from reading it, the exact configuration but I think I might have a foggy glimpse of the idea. If it was tested and miraculously it some how didn't pull in power electrically from its surrounding environment, then I would suspect it of pulling in energy from some where else. From thermal isn't supposed to be possible (Maxwell's demon) but measurements of thermal are possible. We could romp into the question of if the quantum vacuum is falling into the earth (hypothesis) idea for instance, so what if we could some how block half of it and make a water wheel (space time wheel). One then has to then wonder how that would effect space time in the long term or what it would mean to do such a thing. One would then think that orientation would then come into play. There is also the idea that the quantum vacuum holds energy in and of it self, but it is supposed to be at its lowest energy state so... Thanks for sharing as it was interesting. I am just not sure exactly what to make of it. Of course I am in the same boat with the EM drive and some of my other ideas.As Thane Heins' patent agent and someone with a loose MIT connection to Markus Zahn, I was of course very gratified to see "Rodal" post a citation to the newly-issued US#9,230,730.
It took me some time to see how Mr. Heins' claims, though seemingly fanciful, were grounded in genuine innovation. The fact that I knew him in high school helped me to suspend disbelief.
I encourage everyone to also inspect the as-yet-unexamined patent application for the "Perepiteia" itself:
www.google.com/patents/US20140111054
Both above patent documents include competent explanations of what might be termed "the Heins effect." The complete explanation took a great deal of time and work and is an ongoing project.
Yes Virginia, there are undiscovered inventions waiting to be found by the unlikeliest of people, in the unlikeliest of places.
Les Virany BSEE MIT, Registered Patent Agent
Licensed to teach physics in the state of MA.
Hey Les, what a pleasant surprise, a warm welcome to the forum fantastic to see you here!
How did you find us
PS: the "Perepiteia" invention is very interesting to this forum because of the conservation of energy issues associated with EMDrive claims
Thanks Jose. I found this forum on Google, following the reaction to Thane's patent. He has had a credibility problem to date so I am very curious to see what happens now, especially among those who have been in such a hurry to judge his work facetiously.
I'm not sure what direct pertinence his material, which is about coil-based rotating current motors, has on this forum. But it appears so wide-ranging as to affect practically all such motors. (and a transformer, of course) It does not provide any direct insight to, for example, the Minkowski-Abraham controversy, as far as I can see, but at a minimum it seems to be a clear reminder that we don't fully understand how classical electrodynamics coexists with quantum physics. And maybe it will provide somebody with the tools to gain an expanded understanding of EMDrives.
-
#1986 by RotoSequence on 20 Jan, 2016 02:03
-
My initial knee jerk reaction is to say that for the generator to accelerate when spinning that it would be pulling in energy from its surrounding environment. I can't say exactly how it would do so as I don't fully understand from reading it, the exact configuration but I think I might have a foggy glimpse of the idea. If it was tested and miraculously it some how didn't pull in power electrically from its surrounding environment, then I would suspect it of pulling in energy from some where else. From thermal isn't supposed to be possible (Maxwell's demon) but measurements of thermal are possible. We could romp into the question of if the quantum vacuum is falling into the earth (hypothesis) idea for instance, so what if we could some how block half of it and make a water wheel (space time wheel). One then has to then wonder how that would effect space time in the long term or what it would mean to do such a thing. One would then think that orientation would then come into play. There is also the idea that the quantum vacuum holds energy in and of it self, but it is supposed to be at its lowest energy state so... Thanks for sharing as it was interesting. I am just not sure exactly what to make of it. Of course I am in the same boat with the EM drive and some of my other ideas.
This train of thought reminds me of devices that siphon power from transmission lines through electromagnetic forces. Something similar might be at play. -
#1987 by TheTraveller on 20 Jan, 2016 03:14
-
TT, This is exactly what EW does for mode confirmation.Mode shapes are defined by the Electric and Magnetic field distributions !
For sure.
And the distribution patterns / effects of those E&M fields on the end plates and sidewalls of a frustum will cause identifiable current flows in those surfaces, which will cause thermally identifiable unique signatures for each and every resonant mode.
So to confirm a good mode excitation, maybe all that is needed is a thermal image of the end plates and the sidewalls?
I'm a little bit confused because of YOU ALREADY KNOW THIS DATA, and now you come up with the same idea?
Before FEKO, us DIYers didn't have access to software that could model end plate & sidewall currents &:related thermal patterns.
Now we do and so we can roll out a DIYer tool that before only EW had access to.
So existing idea but thanks to FEKO, now available to any DIYer with an ir camera or ir camera adaptor for their phone. -
#1988 by meberbs on 20 Jan, 2016 03:20
-
Congratulations RFPlumber on the successful test.
(And for reference, successful test means you learned something, whether you confirm or reject the hypothesis doesn't matter. For example, SpaceX's landing test during the Jason 3 launch was successful in that they learned about an issue with their landing legs)
Emphasis mine.
I not experimenting with the build. Have seen more than enough test data, some I can't yet disclose, to know what I'm building will work. That is as long as I do a really good job on the build or it becomes rubbish in, rubbish out. If I have thrust issues, I know where is error is and it will be in my build. So I need to do the build very well and do everything possible to excite only ONE high Q mode, which will extend to drilling a small hole in the centre of the small end plate and inserting a loop antenna to physically map out the excited mode.
...
If you go through the effort as thoroughly as it seems that you will, and you are able to demonstrate a good Q and expected resonance frequency, then there will not be any thrust issues caused by your build. In that case, if you do not produce thrust, will you acknowledge that Shawyer's "theory" is wrong?
-
#1989 by TheTraveller on 20 Jan, 2016 03:22
-
In the FEKO sim his internal forces and modes were not symmetrical inside of the cavity.
https://drive.google.com/file/d/0B6juR48k_XoTbnNZT0NmcjBLVzQ/view
Shell,
While it is early days with FEKO sims, that data sure does not look good. More like a dogs breakfast than resonance.
Phil,
who is looking forward to using FEKO to get really good thrust results for all DIY builders. -
#1990 by TheTraveller on 20 Jan, 2016 03:36
-
If you go through the effort as thoroughly as it seems that you will, and you are able to demonstrate a good Q and expected resonance frequency, then there will not be any thrust issues caused by your build. In that case, if you do not produce thrust, will you acknowledge that Shawyer's "theory" is wrong?
For sure.
Except I have data I can't yet share & know any lack of thrust issues I have are due to something I'm not doing right.
I'm following a proven recipe, just some of the recipe ingredients are smugged and left to me to work out. Will get there as I know it works. Following bread crumb trails do have their issues.
Roger has put my design through the SPR software & has given me the resonance freq @ TE013, unloaded Q & specific thrust data. That data has been shared on my EmDriveResearch forum.
https://groups.google.com/forum/m/#!forum/emdriveresearch
My goal is to "Make It So". Which I will do. -
#1991 by Prunesquallor on 20 Jan, 2016 03:44
-
...
For example, SpaceX's landing test during the Jason 3 launch was successful in that they learned about an issue with their landing
...
Wow. OK. in your happy view, what would constitute a failure? -
#1992 by RFPlumber on 20 Jan, 2016 04:06
-
“The hardest thing of all is to find a black cat in a dark room, especially if there is no cat.”
Ok... So what's next? As you can guess I am not exactly excited at the moment. Reading through comments I am glad not to be the only person who believes this last test showed absolutely no thrust. The possibility of no RF in the cavity during all of the tests is very unlikely which leaves one with the only remaining explanation - existing physics describes these kinds of cavities (with CW excitation) perfectly fine. The entire journey felt like doing a lab class in RF - a lot of fun, but everything is 100% according to a textbook.
...Yes, I was hoping to see thrust. But then, if no thrust, I was expecting to see a bunch of different forces during the RF pulse, and we would then have a lot of argument about which of them might be anomalous. Yet, the only 2 forces I ended up seeing are electrostatic and that of air movement... How boring.
From this point on there are no published theories making thrust predictions for these tests. It could be a magic threshold on Q value, a dielectric insert, a pulsed excitation, a day of the week... Or it could be nothing at all. Another negative test will not even contribute to nullifying anything... These thoughts are not particularly motivating...
...So I am kind of reluctant to start building a new shiny frustum from scratch. The way I am thinking to proceed is to try and add improvised flanges to the exiting one, thus hopefully getting rid of the RF leak... then measure Q again, understand the impact of the leak (if only out of curiosity), then clean it all for good with sulfuric acid, apply chemical silver plating solution and see where the Q ends up. Assuming it gets to the ~20,000+ range, it will then be possible to make a test with some HDPE inserts following the EW lead (though honestly their 55 uN thrust trace for TE012 mode looks suspiciously "thermal" in shape). And I could then also try pulsed RF excitation as my generator already has this option... And then this will likely be it. I doubt I will have any "thrust" left to then start replicating EW cavity.RFPlumber - Congratulations on the getting this done!
I had a go at aggregating your data across multiple runs. If one uses the HV deflection as a thrust scale of 260 microNewtons, the answers I get for the RFon - BfRF are:
Runs 1267 58 micro-N +- 194 (2 sigma of highest aggregate midpoint sigma, which was 'Before RF')
Runs 3489 74 micro-N +- 54 (2 * same sigma)
...
Nonetheless I agree you have ruled out thrust in the hundreds of micro-newton range. There is a hint of a signal of low thrust, but not enough data to confirm or refute it. The levels seen may be in the range of experimental Lorentz errors.
Let me know if you think anything here doesn't make sense for any reason.
Cheers, and congrats again!
R.
Thank you. W.r.t those averages, you averaged it across 2 different orientations... I am not sure what was the plan. But a small positive number is actually expected, as the "chimney" force starts to increase (always in the same direction) about 5 s into the RF pulse. Somewhat amazingly it then reverses direction close to (but almost always a bit before) when then RF amplifier is turned off and then continues in that opposite direction for many seconds thereafter.[wood frame]
Sorry, not going to build it. It would take a lot of room in my garage (not to mention time and effort required), and I strongly doubt it will result in producing thrust. I even doubt it will reduce oscillations much as the frustum will pick up any minor excitation and will start oscillating again. It would indeed help with air movement so I could maybe be able to turn and breath during those runs
It is fair not to build it. Here is just some explanation. The purpose is not to produce thrust, but to reduce error bar, so you can say "if there is any thrust, it would be below 1uN" instead of "it would be below 50uN".
Your ceiling may introduce much of the "minor excitation" you see, that's why I suggest a frame. It is easy to build anyway, just four wood sticks tied together to form the pyramid shape.
But since we are on the opposite side of EmDrive, and my purpose is improve "no thrust" claim and your purpose is to find under what condition there is thrust, it is fair for you not to take my suggestion.
Thinking about this more, there would still be air convection inside this enclosure caused by the RF amp hot plate...
My conclusion at this point is that chasing anything below 100 uN is better be done in vacuum.
Well here are my issues.
1. Differing time dimensions. Looking at that control run it seems like you had an oscillation of about 400uN from peak to trough over 37 seconds. You fired up the thing and the oscillations dropped to around 37uN and their frequency increased. I'd like to see your control test data (everything off) superimposed with your test run data showing the same time dimensions and using an absolute displacement.
2. Your first run showed a retrograde force after power off that you attributed to air inflow. I think that also needs to be shown on the second run. Also data from the first run in the East direction shows a record result at rf on of about 0. The bar graphs you are presenting to us this time around shows a recorded of result of max about 100uN in the East direction. I think you need to explain why the data is different.
Also, what are you showing here? You claim only a 37 uN change in the presented data chart from one run but I see a recorded change of max 100 uN on the summary bar graph. What run do the presented data points correspond to (or are they an average of all runs)?
3. Why are you running the high voltage test if it doesn't help isolate variables in the rf injection test? I thought the point of that was to show that any recorded measurements could be explained by electrostatic forces. Are you indicating that the hv run does not correspond to a run where no rf is introduced by the electrostatic forces are the same as a run where rf is injected? If so what is the utility of this form of testing?
I will try my best to answer...
Yes, the idle run is there to show what levels of spurious forces may be present. It does not imply that they are present all the time (look at another idle run which is better). Sitting quietly for a few minutes tends to help. Walking around ruins it. Some test runs are very noisy (6,7,8,12,13), others are quiet. I just picked one quiet run to show that there is no noticeable change at the time of RF pulse. (But what if one is so unlucky that the RF was somehow not present (only) during all those quiet runs? Too bad. Then we missed it.)
The thermal "chimney" / "draft" force is visible on almost all of the runs from this test. It is also prominent on the summary page. I just didn't explicitly marked it this time.
The 39 uN "margin" is from a chart for run Run4-East-HvOverRfAt30s-MP. The summary pages shows 5 um difference (5*13 = 65 uN) for this run for the Rf pulse, this is more than the 39 uN illustrated as the "Before RF" average uses all of the points before the RF pulse while the illustration operates with just 3-4 points closest to the start of the pulse. Statistics is just a tool. It should be used carefully.
The HV test is there to show that we can detect a known small force acting on the pendulum. Hence the assumption that we will also be able to detect an unexpected small force of a similar or larger value.
The HV-only runs were intended to determine the smallest resolvable force level. What they actually showed that as the force is reduced below 200 uN there is then a large "chance" component to detecting the force (as the second HV-only run came up very noisy).
Not wanting to hijack the thread away from Feko discussions I want to just comment on RFPlumber's test results. First I think he has done an excellent job. I see very careful work that has been well presented. I also agree with his assessment. There is no detectable thrust.
...
Thank you.
-
#1993 by meberbs on 20 Jan, 2016 04:12
-
If you go through the effort as thoroughly as it seems that you will, and you are able to demonstrate a good Q and expected resonance frequency, then there will not be any thrust issues caused by your build. In that case, if you do not produce thrust, will you acknowledge that Shawyer's "theory" is wrong?
For sure.
...
All that matters is that you keep an open mind.
Mysterious data that no one else has seen is not an argument. The data I have seen (e.g. Eagleworks, Tajmar, the people on this thread) has been inconsistent with the high levels of thrust claimed by Shawyer, and has not been enough to convince me that there is anything at all, while still leaving open the possibility there is something here.
I'll wait for you to have some data to share, that will hopefully be able to resolve this one way or the other.Wow. OK. in your happy view, what would constitute a failure?
For SpaceX, it would have been if something went wrong that prevented them from getting any landing data (e.g. activating the stage FTS because a stray boat wandered into the landing hazard zone)
For an emdrive test, it would be something that makes all of the data useless (e.g. mis-measured and built the wrong shape cavity)
When you are experimenting, the goal is to learn something, and it isn't too hard to do that even if you don't get the answer you wanted. Once you move into application, you get goals like, "make rockets reusable" (Spacex is still making progress on that, so they haven't succeeded or failed yet.) or "place this satellite in orbit." These have much stricter failure criteria.Quote from: EdisonI have not failed. I've just found 10,000 ways that won't work.
-
#1994 by TheTraveller on 20 Jan, 2016 04:59
-
All that matters is that you keep an open mind.
Of course.
Attached is my recipe from the head chef. Expected performance data is from SPR and not my spreadsheet.
What I need to sort out myself is the coupler design, location & high build quality to achieve close to the predicted Qu/2 = measured or loaded Q of approx 43k.
It will happen. For sure.
Any comments on the 1/2 loop coupler equation I found in an accelerator cavity design paper are most welcome. Will be interesting to see if FEKO can sim this. As it can produce S parameters, should be able to estimate impedance & VSWR from any coupler.
Phil
-
#1995 by RFPlumber on 20 Jan, 2016 05:09
-
It just occurred to me... As RF leaks reduce Q... Anyone thinking they have got "thrust", just introduce a controlled RF leak and see if thrust changes or goes away... If it does not change (which I suspect is going to happen in most cases), this will be a good indicator that their "thrust" is caused by something other than RF fields inside the cavity...
EDIT: Actually, this will not work for induction-heating-related "thrust" (seems to be most common for magnetron tests at ambient air) as the amount of heating will also be reduced in the exact proportion of leaked RF... Should still be good for eliminating Lorentz-produced forces. -
#1996 by RFPlumber on 20 Jan, 2016 07:29
-
Silly me. I only now realized that the EW results described in their original "Anomalous Thrust Production..." paper have not been performed in vacuum. Duh.
...And I kept wondering how most of this paper thrust plots (including one from a dummy load) which I thought had all been performed in vacuum were having all the same now very familiar long post-RF tails I have just got in my garage! Now I understand. ... Also, in this paper there is not a single plot of thrust in the opposite direction?
Anyway, it turns out the only remaining vacuum test today with "thrust" is EW 10 uN from 35W? Detected with the same setup where they have previously seen null Lorentz forces of 9 uN?
This was interesting. Obviously there is no point for me trying to test this further with HDPE disks as 10 uN is way below anything I could reasonably expect to detect (and/or be excited about).
-
#1997 by TheTraveller on 20 Jan, 2016 07:51
-
Silly me. I just now realized that the EW results described in their original "Anomalous Thrust Production..." paper have not been performed in vacuum. Duh.
...And I kept wondering how most of this paper thrust plots (including one from a dummy load) which I thought had all been performed in vacuum were having all the same now very familiar long post-RF tails I have just got in my garage! Now I understand. ... Also, in this paper there is not a single plot of thrust in the opposite direction?
Anyway, it turns out the only remaining vacuum test today with "thrust" is EW 10 uN from 35W? Detected with the same setup where they have previously seen null Lorentz forces of 9 uN?
This was interesting. Obviously there is no point for me trying to test this further with HDPE disks as 10 uN is way below anything I could reasonably expect to detect (and/or be excited about).
If I was you my next step would be to get a real S11 VNA scan, determine your driven freq was correct and then work to get the Ql to a min of 25k.
Make the VNA scan freq width wide enough to get at least 4 good solid dips and use your resonance software to confirm those dips also show up with your software. IE physically and software wise map the nearby modes of your frustum to be sure you have what you think you have. This is also Roger's advise as a good frustum design has no nearby undesirable modes that could be excited by themselves or in a mixed mode dog's breakfast.
There is no point in trying to gen thrust with a dubious resonance and low Q.
Would also be good to measure both forward & reflected power. -
#1998 by oliverio on 20 Jan, 2016 10:19
-
@RFPLUMBER
Did you see the post in which notsosureofit predicted ~5 uN given your power levels and quality factor?
In my opinion your only option is to increase quality factor or noise to a suitable level to disprove his hypothesis, which I find to be the best mathematical formulation of the general effect Shawyer mistakenly describes.
As we all know, the momentum of a photon through dialectics and such, as well as relativistic effects at higher energies, are not perfectly yet described by math. Shawyer's idea is not really anything new (as far as abusing Minkowski-related phenomena to gain momentum, which the government has previously investigsted) but I think we can all agree to be skeptical about his math. In this regard we may as well operate on the best mathematical approach if we are attempting to address the phenomena itself that has been observed and postulated (rather than Shawyer's theory itself). -
#1999 by RERT on 20 Jan, 2016 10:27
-
RFPlumber -
Sounds like your data wasn't what I had thought, so the aggregate numbers I posted don't apply.
I know you've already discussed this in a more nuanced way, but can you boil your result down to thrust per killowatt of
F micro-newtons +- E micro-newtons at (say) 90% confidence?
I guess all results really come down to this form. The effect is confirmed if F is much larger than E. It's no longer worth pursuing unless F+E is above some threshold. I can't recall what level of thrust per kilowatt is regarded here is a threshold to be practically useful for, say, station keeping, but I don't think it's huge.
My sense is that you have seen at best a small F, but quite large E, and F+E is still interesting. However, it's your data, and I'd be very interested in your numbers.
In any case, thanks for your previous response.
R.
Other 30% I just think I know 
