Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1802579 times)

Offline SeeShells

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.. I'm working on my DC analysis and I've made significant progress. It's not ready yet, but I think it will be interesting.

Todd

Have you seen this papers by Pinheiro?

http://arxiv.org/abs/1502.06288

http://arxiv.org/pdf/1502.01917.pdf

http://arxiv.org/abs/1208.3458

http://arxiv.org/abs/1104.5011

http://arxiv.org/abs/0901.3726

http://arxiv.org/abs/0802.0284

http://arxiv.org/abs/physics/0511103
You have been a busy little bee and it looks like I'm going to be taking some time today to dig into this very nice collection of theories, thoughts and speculations. Dang, it looks like fun. I'll be back on later a little more brain fried. Thanks for the brain cramp ahead of time.
Shell

Offline Rodal

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Ok - here is what the Brady cavity looks like in 3D. x, y, and z views. The y view looks pretty good as it should because that is the symetric view of both cavity and antenna. The end view and the other side view, not so much as the antenna is not symetric with those view directions.

As they are shown, the fields do not appear to be compatible, continuous if one envisions what happens around the circumference.

How can the field look like this



and when looked at a 90 angle look like this:



Is MEEP performing the calculations in a global x, y, z Cartesian coordinate system?

If so, is the package doing the post-processing plots a MEEP package? or is it an external package? If it is an external package, have MEEP users used this same package to plot  electromagnetic fields in conical cavities ?

I think we have to take a look at how:

1) MEEP outputs the vector electromagnetic fields.  Does MEEP output the vector components in all 3 directions Ex Ey and Ez, and Bx By and Bz?

2) How does the Postprocessing package take the data for Ex Ey and Ez, and Bx By and Bz and produce a contour plot?

3) Can the postprocessing package produce a vector field plot instead of a contour plot?

Either that, or we need 3-D plots to understand what is going on
« Last Edit: 06/22/2015 09:29 PM by Rodal »

Offline SeeShells

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Cavity Q refresher: http://www.allaboutcircuits.com/textbook/alternating-current/chpt-6/q-and-bandwidth-resonant-circuit/
CLIP
I've looked for six sided hexagon horn antennas and found very little info but nothing bad. So I am open to thoughts and ideas. You guys are way smarter than this silly girl.

Shell

Shell -
From a short discussion with some waveguide colleagues I get the impression that hexagonal should work pretty well - I didn't go into what I was asking for, just discussions of circular vs rectangular vs hexagonal wg.   mode calculations are somewhat different of course but hex or octagonal etc are just closer approximations to circular (insert spherical chicken in a vacuum joke here). 

I think matching the horn geometry to frustum geometry is likely a good idea but thats just because it "feels right".   I will try playing with it tonight if I can.

Love all the different experimental setups - the more the merrier.   

Herman

What did the chicken say in space? Nothing, cuz they can't hear you cluck in space.

We also need to realize I'm shoving RF into this thing from what I consider a very dirty almost uncontrolled RF device and it will probably range over 3 harmonic modes, plus the kicking on and off of the magnetron's power supply. It looks like a witch's brew where anyone is going to be hard pressed to write down a clean formula. I thank you for your thumbs up good gut feeling, it means alot.
What do you call a chicken in a blender? A Frustum?

Enough of being silly, I don't want to be slapped by the moderator, I have some serious reading to get into. Welcome Aboard the Tar Baby Chicken Frustum.

Shell

Offline rfmwguy

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did a search and did not find this... hope it was not posted yet


Quote
AIAA Propulsion and Energy Forum and Exposition
27–29 July 2015
Hilton Orlando, Orlando, Florida
...
TUESDAY, JULY 28, 2015
NFF-04. Future Flight Propulsion Systems
Chair(s): Gregory Meholic (The Aerospace Corporation)
Co-Chair(s): Heidi Fearn (California State University, Fullerton)
2:30 PM - 5:30 PM; Lake Nona A
...
3:30 PM - 4:00 PM
Design and First Measurements of a Superconducting Gravity-Impulse-Generator
Istvan Lörincz; Martin Tajmar

4:00 PM - 4:30 PM
Replication and Experimental Characterization of the Wallace Dynamic Force Field Generator
Martin Tajmar

4:30 PM - 5:00 PM
New Theoretical Results for the Mach Effect Thruster
Heidi Fearn

5:00 PM - 5:30 PM
Direct Thrust Measurements of an EMDrive and Evaluation of Possible Side-Effects
Martin Tajmar


I wonder if someone from this thread could attend the conference and if there is a following Q/A, even mention some of the experiments discussed here, ask questions, etc.

I did post a link but none of the sessions, thanks. Note on the Mach Effect Thruster...a competing technology also presented last year at the Ohio conference. Seems we might have a horse race ;)

Offline aero

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Ok - here is what the Brady cavity looks like in 3D. x, y, and z views. The y view looks pretty good as it should because that is the symetric view of both cavity and antenna. The end view and the other side view, not so much as the antenna is not symetric with those view directions.

As they are shown, the fields do not appear to be compatible, continuous if one envisions what happens around the circumference.

Is MEEP performing the calculations in a global x, y, z Cartesian coordinate system?

If so, is the package doing the post-processing plots a MEEP package? or is it an external package? If it is an external package, have MEEP users used this same package to plot  electromagnetic fields in conical cavities ?

I think we have to take a look at how:

1) MEEP outputs the vector electromagnetic fields.  Does MEEP output the vector components in all 3 directions Ex Ey and Ez, and Bx By and Bz?

2) How does the Postprocessing package take the data for Ex Ey and Ez, and Bx By and Bz and produce a contour plot?

3) Can the postprocessing package produce a vector field plot instead of a contour plot?

Perhaps -

x, y, z cartesian coordinates as I understand it.

h5topng - It is the program packaged with Meep, prepared at MIT for use with Meep. As far as I know it is commonly used with Meep data.

The components - Ex, Ey, Ez and Hx, Hy, Hz are available for output. The user must ask for them to output them. They go into seperate files. Each file comes with real and imaginary data sets each giving x, y, z components of field strength, and ofcourse there is a time dimension available.

How does h5topng work? I have no idea.

Vector field instead of contour? I don't think so. http://ab-initio.mit.edu/h5utils/h5topng-man.html

If someone really wanted to look at the details of the data then IMO ParaView is the package to use. But I find it difficult to use and ParaView is a CPU and memory hog on the same order as Meep. And why not? The Ez file alone for these 3D runs is over 4GB. Pulling that file into memory and manipulating it is bound to take some resources. OF course, ParaView is designed for parallel processing on supercomputers much as is Meep so if anyone has one handy ...

I'll see about making a time stationary output file to look at. That would be a lot smaller file to work with but have no evolving information.
« Last Edit: 06/22/2015 09:57 PM by aero »
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Offline rfmwguy

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Cavity Q refresher: http://www.allaboutcircuits.com/textbook/alternating-current/chpt-6/q-and-bandwidth-resonant-circuit/

Excellent Link!! Thanks.

Have you developed an approach for measuring Q in you DUT?    I tend to think in of "Q as Ctr Freq/3dB  Bandwidth" from the filter world as well and have been pondering this.  VNA? 

BTW - thanks for the earlier welcome and yes I am (mostly) an old RF guy.

Herman

Thats the big question in my mind...what the F the Q is ;). I can take my DUT and have S11 and S22 run which will get me close. The spreadsheet Traveller made for me was a 50K Q, which is what, 49 MHz 3dB BW? Highly suspicious by nevertheless I'll give it a whirl.

Offline aceshigh

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I did post a link but none of the sessions, thanks. Note on the Mach Effect Thruster...a competing technology also presented last year at the Ohio conference. Seems we might have a horse race ;)

well, Paul March, from Eagleworks Lab, based his Q-Thruster on his previous work with Woodward's Mach Effect. He said here at NSF that he thinks Q-Thrusters/EM-Drives and Mach Effect Thrusters are two sides of the same coin.

I said "q-thrusters/em-drives", but I am not sure they are the same thing or how they relate... (well, Dr White probably thinks both work based on Quantum Vacuum Fluctuations)

Offline rfmwguy

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I did post a link but none of the sessions, thanks. Note on the Mach Effect Thruster...a competing technology also presented last year at the Ohio conference. Seems we might have a horse race ;)

well, Paul March, from Eagleworks Lab, based his Q-Thruster on his previous work with Woodward's Mach Effect. He said here at NSF that he thinks Q-Thrusters/EM-Drives and Mach Effect Thrusters are two sides of the same coin.

I said "q-thrusters/em-drives", but I am not sure they are the same thing or how they relate... (well, Dr White probably thinks both work based on Quantum Vacuum Fluctuations)

Tell you what, KML here might be presenting a paper soon...very interesting results in a classic rectangular waveguide with & without dielectrics. I would not have predicted that. The plot thickens ;)

Offline Rodal

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Ok - here is what the Brady cavity looks like in 3D. x, y, and z views. The y view looks pretty good as it should because that is the symetric view of both cavity and antenna. The end view and the other side view, not so much as the antenna is not symetric with those view directions.

As they are shown, the fields do not appear to be compatible, continuous if one envisions what happens around the circumference.

Is MEEP performing the calculations in a global x, y, z Cartesian coordinate system?

If so, is the package doing the post-processing plots a MEEP package? or is it an external package? If it is an external package, have MEEP users used this same package to plot  electromagnetic fields in conical cavities ?

I think we have to take a look at how:

1) MEEP outputs the vector electromagnetic fields.  Does MEEP output the vector components in all 3 directions Ex Ey and Ez, and Bx By and Bz?

2) How does the Postprocessing package take the data for Ex Ey and Ez, and Bx By and Bz and produce a contour plot?

3) Can the postprocessing package produce a vector field plot instead of a contour plot?

Perhaps -

x, y, z cartesian coordinates as I understand it.

h5topng - It is the program packaged with Meep, prepared at MIT for use with Meep. As far as I know it is commonly used with Meep data.

The components - Ex, Ey, Ez and Hx, Hy, Hz are available for output. The user must ask for them to output them. They go into seperate files. Each file comes with real and imaginary data sets each giving x, y, z components of field strength, and ofcourse there is a time dimension available.

How does h5topng work? I have no idea.

Vector field instead of contour? I don't think so. http://ab-initio.mit.edu/h5utils/h5topng-man.html

If someone really wanted to look at the details of the data then IMO ParaView is the package to use. But I find it difficult to use and ParaView is a CPU and memory hog on the same order as Meep. And why not? The Ez file alone for these 3D runs is over 4GB. Pulling that file into memory and manipulating it is bound to take some resources. OF course, ParaView is designed for parallel processing on supercomputers much as is Meep so if anyone has one handy ...

I'll see about making a time stationary output file to look at. That would be a lot smaller file to work with but have no evolving information.

Let's try to work through this.  The standard convention is to take z as the axis of symmetry (the longitudinal axis of the cone) but the way you labeled them, it looks like x is your axis of symmetry, is that correct?

If x is the axis of symmetry, then y and z are perpendicular to it. 
On the trapezium-looking cross section with axis y perpendicular to it, the axis of the trapezium are x and z, is that correct?

OK, if the answer is yes, on your y plot, what are you plotting:

Ex ?

Ez?

Hx?

Hz?
« Last Edit: 06/22/2015 10:33 PM by Rodal »

Offline deltaMass

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After more than 20 years of almost continuous experimentation, Woodward still has nothing that has been independently verified by at least two other labs. This is a heads-up that you might be in this for the long haul.

Offline demofsky

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I have started conducting tests on my linear EmDrive.   The test assembly is fully untethered using a battery power source and IR remote control for RF on/off.  Forces are measured using an AND MC-10K 10.1kg x 0.001g scale.   The initial tests are using a 4"x3"x0.25" Al2O3 ceramic dielectric.  During tests the scale and unit are enclosed within a cardboard breeze break.    The rectangular non-tapered resonator internal dimensions are 6.5"x3.25"x13", mode TE102.  "Up Orientation" means the fixed end with the feedpoint and the dielectric plate is on top, the adjustable end is on bottom closest to the scale.   In all orientations the RF PA, battery, and sample port heat sink are on top of the unit, furthest from the scale.

The initial tests with dielectric were promising, with forces very close to the 15mg predicted:

http://kl.net/emdrive/20150621-test-9-al2o3-up.png


Unfortunately, I also saw similar forces in most of the control experiments, such as with no dielectric installed:

http://kl.net/emdrive/20150621-test-32-no-dielectric-up.png


And even with the unit suspended by a wood stand just above the scale (to prevent contact), with ceramic flooring tiles placed on the scale tray for similar loading:
http://kl.net/emdrive/20150621-test-33-no-dielectric-up-suspended-tiles.png


Only the dummy load test did I not see any change in scale output.   The output of the isolator is directly connected to the dummy load that normally takes the output of the sampling port, thus bypassing the RF cavity:

http://kl.net/emdrive/20150621-test-36-no-dielectric-dummy-load.png


Most likely there is an RFI problem with the scale.  I'm going to attempt to shield the scale with the unit suspended above it to prove that it is RFI.

I have to say that these are very intriguing results!  While we are all waiting to see if you can eliminate RFI interference on your scale as the cause for these results, I would like to point out a couple of notable things:

1). The performance with and without dielectrics reflects Shawyer's and Yang's experience.

2).  Much more interesting from my perspective are the declining lows in your first experiment with the dielectrics.  This is a very similar pattern to the Eagleworks tests With a dielectric insert.  It was speculated at the time that this might have been due to out gassing but I can't see that happening with a ceramic dielectric!!

So what the heck is happening with the dielectrics?

There is a more subtle pattern of declining lows without the dielectrics, but it is more pronounced with them present. 

So either there is some type of ongoing electrical (electrostatic?) interference with the digital scale once the power is off, significant out gassing from somewhere, or we are looking some very interesting theoretical issues here folks - and evanescent waves are just not going to cut it...

Edit:  After checking the scale,  it is apparent that the unit is getting lighter and so we have to add ballooning to the possible effects, with the dielectrics thermal mass sustaining the effect.
« Last Edit: 06/22/2015 11:52 PM by demofsky »

Offline WarpTech

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...
So what the heck is happening with the dielectrics?

There is a more subtle pattern of declining lows without the dielectrics, but it is more pronounced with them present. 

So either there is some type of ongoing electrical (electrostatic?) interference with the digital scale once the power is off, significant out gassing from somewhere, or we are looking some very interesting theoretical issues here folks - and evanescent waves are just not going to cut it...

I would recommend keeping it "OFF" until the Rig thermally stabilizes. The decrease in weight when it is off could be due to heating of the air inside, "balloon" effect with air-mass leaking out.
Todd

Offline TheTraveller

Roger Shawyer kindly sent me a copy of his EMDrive paper that is currently under peer review. All I can say is WOW. All doubt will be removed. Apologises but can't yet share it.

Would make one comment.

The EMDrives on the IXS Clark are old tech, working at only 4N/kW. If  you think the voyage times here

http://emdrive.wiki/Potential_EMDrive_solar_system_explorer_ship

look good, well lets just say they need to be revised downward quite a bit.

Still in bed, recovering slower than desired, damn old age, but getting there. My build start still looks like 4 to 6 weeks away but the design steadly improves. Force measurement system will follow what Shawyer did in the Flight Thruster demo setup as attached. Hang it from a spring and measure the generated forces on a digital scale. Typical KISS enginerring.
« Last Edit: 06/22/2015 11:48 PM by TheTraveller »
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Offline demofsky

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...
So what the heck is happening with the dielectrics?

There is a more subtle pattern of declining lows without the dielectrics, but it is more pronounced with them present. 

So either there is some type of ongoing electrical (electrostatic?) interference with the digital scale once the power is off, significant out gassing from somewhere, or we are looking some very interesting theoretical issues here folks - and evanescent waves are just not going to cut it...

I would recommend keeping it "OFF" until the Rig thermally stabilizes. The decrease in weight when it is off could be due to heating of the air inside, "balloon" effect with air-mass leaking out.
Todd

Agreed.  This is the most likely effect and not interference with the scale.  Happily this is easy to rectify by flipping the fustrum and seeing what happens.

Offline rfmwguy

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...
So what the heck is happening with the dielectrics?

There is a more subtle pattern of declining lows without the dielectrics, but it is more pronounced with them present. 

So either there is some type of ongoing electrical (electrostatic?) interference with the digital scale once the power is off, significant out gassing from somewhere, or we are looking some very interesting theoretical issues here folks - and evanescent waves are just not going to cut it...

I would recommend keeping it "OFF" until the Rig thermally stabilizes. The decrease in weight when it is off could be due to heating of the air inside, "balloon" effect with air-mass leaking out.
Todd

I like the way you think...my own plans are for 30 minutes on, 30 minutes off. I understand the need for short term pulses at much higher power levels than what I am operating at. Guess that comes with my burn-in mentality from days past.

Offline Prunesquallor

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In reference to:

http://emdrive.wiki/Potential_EMDrive_solar_system_explorer_ship

Quote
Todd "WarpTech" and deltaMass have shown in NSF EM Drive Thread 2 that Dr. White's derivation contains an error in the integration. frobnicat has discussed in NSF EM Drive Threads 1 and 2 other flaws in this analysis. For the ion rocket consideration, the kinetic energy of the propellant needs to be properly taken into account.

Added 23 June 2015. As far as I (TheTraveller) know, none of the NSF members above has contacted Dr. White to discuss their concerns with his calculations. Until they do that and publish their corro showing Dr. White has agreed with their concerns and published a modified results paper, Dr. White's current published results stand and trumps arm chair critics.

Didnt realise comments made in NSF trump those made by the head of NASA's JSC Eagleworks, especially if Dr. White was never contacted.

If you guys have an issue with what Dr. White has published, you should 1st take it up with him directly and resolve your differences. You don't do what you did, on a public forum, without giving him the right to respond and defend the statements he made in the papers Appendix A.

So has any of the 3 mentioned NSF forum members contacted Dr. White to discuss their counter claims?

BTW, the Ion drive ship accelerates, inside it's inertial reference frame, and follows A = F/M. Don't see where a distant observers measurement of starting velocity & KE comes into that equation?

Well someone made an error in that write up. 8000 N/90,000 kg is 0.088 m/s2 NOT 0.088 g's.
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Offline aero

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X is the axis of symmetry. The antenna is to the +Y edge of the cavity. Z completes the coordinate system.

I am plotting a snap shot of the x, y and z corrdinate values of the Ez field. More than that you'd have to ask a physicist.
« Last Edit: 06/23/2015 01:04 AM by Chris Bergin »
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Offline Chris Bergin

I know you are all clever people, but I'm sure a lot of you have never been on an internet forum before ;)

1) Read the site rules. There are rules on how to conduct yourself here.

2) Don't embed massive images. Attach them. It kills the thread if you have a massive image messing up the width.

3) Quote someone correctly. It's very easy and self explanatory. Badly quoting (no name and link to post) is open to changing the quote and that's a bad day if that happens.

4) I'm not being an arse, I'm just trying to keep some order on this crazy thread I don't understand ;)

Offline zen-in

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I have started conducting tests on my linear EmDrive.   The test assembly is fully untethered using a battery power source and IR remote control for RF on/off.  Forces are measured using an AND MC-10K 10.1kg x 0.001g scale. 

...

Only the dummy load test did I not see any change in scale output.   The output of the isolator is directly connected to the dummy load that normally takes the output of the sampling port, thus bypassing the RF cavity:
Most likely there is an RFI problem with the scale.[/b]  I'm going to attempt to shield the scale with the unit suspended above it to prove that it is RFI.


That is very interesting.  Can I make a constructive suggestion?   Why don't you put the dummy load (or a suitably sized resistor for DC power) inside the cavity and collect data with that configuration?   This was my criticism of the Eagleworks lab tests going back to thread 1.    Have you posted a picture of your apparatus?  videos?   Good work!

Offline SeeShells

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Time to start my build...
I like being able to get into the cavity to change the Microwave antenna and the endplates plus being able see inside the maelstrom of microwave cavity activity might prove to be a plus.

I have some thoughts on the testing rig and still working those out. I like the fulcrum with the oil damping idea and I'll post a drawing of my thoughts later, but I want to get the Frustum built first.

Shell
Remember to use a smoke source (or Dry Ice if you can get it ) and if possible try inputs in multiple different locations spaced along the length of the cavity. You "might" see different results from different locations?.

I'll remember to do a smoke test (no, not the old tech test either, ;) ).  I did design the thing to try different locations and I'm sure there will be surprises during this testing.

Thanks,
Shell

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