Author Topic: EM Drive Developments - related to space flight applications - Thread 2  (Read 2170751 times)

Offline Rodal

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Lucky that Nasa hasn't stopped the experiments.  It would be a more than a little upsetting if they stoped the progress Eagle works has made.
NASA has surely not increased Eagleworks little tiny teeny budget and we haven't heard from Paul March since the NSF article...

They are downplaying it.  At NASA Glenn's site they are directing interested people to an ex-employee (Millis) and not saying anything about Eagleworks work... :(

Everybody interested should write to their congressmen
« Last Edit: 05/14/2015 06:33 PM by Rodal »

Offline Notsosureofit

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I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.

I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.

As usual, any comment is very welcome.

Yes, but am I correct as seeing the a and b terms in the frustum case as generating Doppler-shifted sidebands ? (the alternative being non-linear terms)

This would suggest that the EW interferometer should replace the "pillbox" cavity with a frustrum and analyze by including a Fabry-Perot into the system?   (might need a mode-locked laser as well.)

Offline SeeShells

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Lucky that Nasa hasn't stopped the experiments.  It would be a more than a little upsetting if they stoped the progress Eagle works has made.
NASA has surely not increased Eagleworks little tiny teeny budget and we haven't heard from Paul March since the NSF article...

They are downplaying it.  At NASA Glenn's site they are directing interested people to an ex-employee (Millis) and not saying anything about Eagleworks work... :(

Everybody interested should write to their congressmen
Yes! I have done a letter and also urge you to do so, oh also beg your friends and relatives too.

Offline StrongGR

I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.

I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.

As usual, any comment is very welcome.

Which news, can you elaborate?

NASA reporting that there is no warpdrive spacecraft and downplaying Eagleworks:

See:

http://news.yahoo.com/no-warp-drive-nasa-downplays-impossible-em-drive-193528141.html

I tried to post this but the moderators removed my post.

Offline StrongGR

I am back with an updated draft after some terrible news around about NASA dismissing these researches. They should not as, otherwise, it could happen as with Galilei having his detractors even not trying to look in the telescope, just dismissing on faith.

I have analysed the case of the frustum and the results appear to be striking. One must admit that geometry comes to rescue not just general relativity. For this particular geometry the cavity can be made susceptible to gravitational effects if your choice of the two radii of the cavity is smart enough. This is something to be confirmed yet, just my theoretical result, but shocking anyway.

As usual, any comment is very welcome.

Yes, but am I correct as seeing the a and b terms in the frustum case as generating Doppler-shifted sidebands ? (the alternative being non-linear terms)

This would suggest that the EW interferometer should replace the "pillbox" cavity with a frustrum and analyze by including a Fabry-Perot into the system?   (might need a mode-locked laser as well.)

I agree. This would make a tunable device to measure with.

Offline StrongGR

Lucky that Nasa hasn't stopped the experiments.  It would be a more than a little upsetting if they stoped the progress Eagle works has made.
NASA has surely not increased Eagleworks little tiny teeny budget and we haven't heard from Paul March since the NSF article...

They are downplaying it.  At NASA Glenn's site they are directing interested people to an ex-employee (Millis) and not saying anything about Eagleworks work... :(

Everybody interested should write to their congressmen

NASA cannot increase spending for this with all the scientific community complaining and crying.

Offline Einstein79

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Reading this:

Siegel said he is seeing claims of thrust happening just a few times over many tests, with a frequency that is "not inconsistent with random chance." Further, the thrust that was produced in these rare instances was apparently just above the margin of error for measurement, he added.

from this article:

http://news.yahoo.com/no-warp-drive-nasa-downplays-impossible-em-drive-193528141.html

makes me think that maybe the drive is the wrong shape.

It has been stated by someone, not sure who, that the thrust was the result of the waves constructively interfering on the larger diameter and destructively interfering on the other, smaller, diameter. Also, the waves are allowed to travel freely in the cavity so that the photons have multiple paths. Because thrusts measured are alleged to simply be error and a "random chance" due to the multiple optical paths, then seems to me that this has now become an optimization problem.

Maybe we can change the dimensions to force coherence by making the total optical path shorter which would also decrease the temperature and make it more efficient. Maybe the "slits" for the device that were originally proposed should be placed before the source to split the beam so we can control the path length and will know the phase shift, similar to a Michelson or Mach-Zehnder interferometer.

Any thoughts?   


Offline TheTraveller

...
Note the frequency is NOT 3.85GHz. There are THREE factors in the Df equation, Small End diameter, Big End diameter and FREQUENCY.

Look at this image:  http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830138

for those dimensions and look at the horizontal axis for frequency.  At that frequency the Design Factor is still below 0.5

Shawyer's design factor is practically unaffected by frequency except near the cut-off frequency for the small diameter.

Shawyer's Design Factor is highest at lowest frequency (near cut-off) and it decreases with frequency

See my equationshttp://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110

Houston we have a problem.

Working it.

Ok sorted. Good to go.
« Last Edit: 05/14/2015 08:30 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
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Offline Rodal

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...
Note the frequency is NOT 3.85GHz. There are THREE factors in the Df equation, Small End diameter, Big End diameter and FREQUENCY.

Look at this image:  http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=830138

for those dimensions and look at the horizontal axis for frequency.  At that frequency the Design Factor is still below 0.5

Shawyer's design factor is practically unaffected by frequency except near the cut-off frequency for the small diameter.

Shawyer's Design Factor is highest at lowest frequency (near cut-off) and it decreases with frequency

See my equationshttp://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110

Houston we have a problem.

Working it.

Notice that the Design Factor of Shawyer approaches this value for high frequencies (it becomes practically independent of frequency)

Limit[DesignFactor, f -> Infinity]  = (bD^2 - sD^2)/(bD^2 + sD^2)

The highest value of the Design Factor is reached at frequencies just a little over the cut-off frequency for the small end:

Cut-Off frequency for small end= cM/(cst*sD)   

Equations: http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374110#msg1374110

For more limits see this http://forum.nasaspaceflight.com/index.php?topic=36313.msg1374114#msg1374114

Example

bD=0.2440 m ;sD=0.1450 m ;cMedium=299705000 m/s (Air)

which has a cut-off frequency associated with the small diameter of 1.21136 GHz

For the Flight Thruster, the Design Factor approaches 0.478 at infinite frequency:

Limit[DesignFactor, f -> Infinity]  = (bD^2 - sD^2)/(bD^2 + sD^2) = 0.478
« Last Edit: 05/14/2015 07:43 PM by Rodal »

Offline TheTraveller

Thanks Dr. Rodal for taking the time to point out my error. Fixed now. Get a Df curve like yours that peaks and then goes to zero as the Guide Frequency goes below CutOff Frequency for the small end.

Interesting interactions.

Keeping small end (g2) Guide Wavelength just above CutOff Wavelength, while operating at a Rf frequency which will generate a high Df, adjusting the length to obtain length resonance at the operation Rf frequency.

The interactions are making sense. My gut is not so much in knots. Starting to feel confident in being able to generate at least 1g of force. Calcs say more like 2g but then the cavity needs a Q of around 50,000, which using spherical end caps should help to make a reality.

Oh BTW obtaining length cavity resonance, which I believe is what is seen doing a spectrum sweep, may not generate any thrust as the small end guide wavelength may be bigger than the cutoff wavelength with the result that little or no significant energy reaches the small end to bounce back.

Shields up. Rock throwing time.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline tchernik

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Thanks Dr. Rodal for taking the time to point out my error. Fixed now. Get a Df curve like yours that peaks and then goes to zero as the Guide Frequency goes below CutOff Frequency for the small end.

Interesting interactions.

Keeping small end (g2) Guide Wavelength just above CutOff Wavelength, while operating at a Rf frequency which will generate a high Df, adjusting the length to obtain length resonance at the operation Rf frequency.

The interactions are making sense. My gut is not so much in knots. Starting to feel confident in being able to generate at least 1g of force. Calcs say more like 2g but then the cavity needs a Q of around 50,000, which using spherical end caps should help to make a reality.

Oh BTW obtaining length cavity resonance, which I believe is what is seen doing a spectrum sweep, may not generate any thrust as the small end guide wavelength may be bigger than the cutoff wavelength with the result that little or no significant energy reaches the small end to bounce back.

Shields up. Rock throwing time.

This is great. Best of luck.

My mechanic/EM engineering skills are nearly nil, but I'm still an engineer of a different sort and I can tell when people know their stuff. Keep us posted.
« Last Edit: 05/14/2015 09:12 PM by tchernik »

Offline Rodal

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Thanks Dr. Rodal for taking the time to point out my error. Fixed now. Get a Df curve like yours that peaks and then goes to zero as the Guide Frequency goes below CutOff Frequency for the small end.

Interesting interactions.

Keeping small end (g2) Guide Wavelength just above CutOff Wavelength, while operating at a Rf frequency which will generate a high Df, adjusting the length to obtain length resonance at the operation Rf frequency.

The interactions are making sense. My gut is not so much in knots. Starting to feel confident in being able to generate at least 1g of force. Calcs say more like 2g but then the cavity needs a Q of around 50,000, which using spherical end caps should help to make a reality.

Oh BTW obtaining length cavity resonance, which I believe is what is seen doing a spectrum sweep, may not generate any thrust as the small end guide wavelength may be bigger than the cutoff wavelength with the result that little or no significant energy reaches the small end to bounce back.

Shields up. Rock throwing time.

Congratulations on fixing it.

I see some differences with my plot using Mathematica.  One minor, immaterial difference is that Excel artificially brings the value of the Design Factor down to zero for frequencies below the cutoff frequency and it artificially draws a vertical line at the cutoff frequency.  Mathematica does not, because the Design Factor does not go down to zero below the cut-off frequency, actually its value becomes a Complex number below the cutoff frequency (since it involves the Square Root of a negative number), and the vertical line shouldn't be there.  In reality there is no Real value of the Design Factor below the cut-off frequency associated with the small diameter.  That's a quirk with Excel.

The other thing is that the curvature in your plot looks different than mine. 
Perhaps it is because my plot goes to 4 GHz and your plot goes to a frequency not as high ?
Perhaps it is because Excel does not plot the vertical part of the knee of the curve, since to do so would involve fine discretization of the curve near the cut-off point.   In any case, if not plotted to 4 GHz, it would be wise to double check it and see what whether they look more alike if you plot it up to 4 GHz.

Thanks.  Congratulations again to you persistent digging of Shawyer's literature to understand what he meant by the different variables, particularly lambdg1 and lambdag2.
« Last Edit: 05/14/2015 09:57 PM by Rodal »

Offline TheTraveller

Thanks Dr. Rodal for taking the time to point out my error. Fixed now. Get a Df curve like yours that peaks and then goes to zero as the Guide Frequency goes below CutOff Frequency for the small end.

Interesting interactions.

Keeping small end (g2) Guide Wavelength just above CutOff Wavelength, while operating at a Rf frequency which will generate a high Df, adjusting the length to obtain length resonance at the operation Rf frequency.

The interactions are making sense. My gut is not so much in knots. Starting to feel confident in being able to generate at least 1g of force. Calcs say more like 2g but then the cavity needs a Q of around 50,000, which using spherical end caps should help to make a reality.

Oh BTW obtaining length cavity resonance, which I believe is what is seen doing a spectrum sweep, may not generate any thrust as the small end guide wavelength may be bigger than the cutoff wavelength with the result that little or no significant energy reaches the small end to bounce back.

Shields up. Rock throwing time.

Congratulations on fixing it.

I see some differences with my plot using Mathematica.  One minor, immaterial difference is that Excel artificially brings the value of the Design Factor down to zero for frequencies below the cutoff frequency and it artificially draws a vertical line at the cutoff frequency.  Mathematica does not, because the Design Factor does not go down to zero below the cut-off frequency, actually its value becomes a Complex number below the cutoff frequency (since it involves the Square Root of a negative number), and the vertical line shouldn't be there.  In reality there is no Real value of the Design Factor below the cut-off frequency associated with the small diameter.  That's a quirk with Excel.

The other thing is that the curvature in your plot looks different than mine. 
Perhaps it is because my plot goes to 4 GHz and your plot goes to a frequency not as high ?
Perhaps it is because Excel does not plot the vertical part of the knee of the curve, since to do so would involve fine discretization of the curve near the cut-off point.   In any case, if not plotted to 4 GHz, it would be wise to double check it and see what whether they look more alike if you plot it up to 4 GHz.

Thanks.  Congratulations again to you persistent digging of Shawyer's literature to understand what he meant by the different variables, particularly lambdg1 and lambdag2.

I test for the potential of a negative sqrt and if found set the value to zero, so yes for frequencies below cutoff, the Df is forced to zero.

It is interesting playing with Rf frequency & small diameter, which watching how cutoff frequency and guide frequency interplay. I found it is possible to get small end guide frequency to be just above small end cutoff frequency, which is a condition Shawyer says gives good thrust.

Then need to adjust big end diameter to get good Df and then adjust small end to big end spacing to get cavity length resonance.

As Shawyer said, this is not easy, which I believe, and why they developed custom in-house software to make finding optimal parameter mixes quicker and less hunt and peck or cut and try.

What all this tells my gut, is this is real as it all hangs together. Have seen no engineering Red Herrings. BUT and a BIG BUT, there is secret squirrel sauce involved and if you don't get the secret squirrel sauce right, there is no thrust. My job now is to work out the secret squirrel sauce, how to apply it, when and where.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline deltaMass

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If you happen to be using Excel, I have found the bog standard Solver plug-in very efficacious for problems involving optimisation with several variables. The trick to making it purr is intelligent setting of the constraints.

Offline frobnicat

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Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/



Well done.

Nicely rolled cavity walls.

Have you tried to calibrate your pendulum test rig by using a small spring scale to see how much force is needed to pull the cavity forward (toward the big end) say 1mm?

Doing this will give you some info on how much force you will need to generate to see some movement.

Maybe I should feel ashamed to propose the following calculation with all those heavy weight equations flying around, but since nobody is taking a bite at it :
a hanging swing pendulum like that has, for small deviations, a linear dependency between force (thrust) F and displacement d  F=(m*g/h)*d  where h is length of strings and m the mass of test article and g local gravity. As a first guess, with m=2kg (or more like 5kg ?) and h=2m that's in the ballpark of 10mN/mm (milliNewton per millimetre) or 10N/m. Quite remarkably similar to Eagleworks balance apparent stiffness, making this mechanical setup basically as sensitive (displacement wrt thrust wise). If a linear displacement sensor of m resolution were used it could probe into N effects, provided proper casing to isolate from drafts and good damping where strings are suspended.

Can you confirm :
- weight of system 2kg, more ?
- height of doorway, or rather length of strings about 2m ?
- graduations marks spacing about 1cm ?

The graduations marks on the video appear about 1cm apart, there is no obvious swing or displacement at power-on visible above, roughly eyeballing 1mm. That gives an upper order of magnitude bound for a thrust (if any) below 10mN/kW for this blazing fast experiment setup. Kudos, and stay safe.

Offline TheTraveller

If you happen to be using Excel, I have found the bog standard Solver plug-in very efficacious for problems involving optimisation with several variables. The trick to making it purr is intelligent setting of the constraints.

Thanks. Will have a look.

Do use "What if Goal Seek" to calc cavity length to get resonance to a desired value (input Rf frequency). Works a charm.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Online WarpTech

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If microwaves were easily contained there wouldn't be a multi billion dollar industry for the testing and consultation of microwave containment.

Seriously, its a big problem. I was amused by this before but when people start using high powered dirty sources to corrupt bands of the spectrum I get angry. I've processed too many Earth Observing land surface experiments that were corrupted and unusable outside of Canada and the US due to unlicensed device usage. It is perplexing that a forum dedicated to spaceflight would encourage such bad form.

We plan to enclose our system in many layers of laminated microwave absorbing sheets:
http://www.lessemf.com/259.pdf

Try putting this on the inside, on the conical wall at the big end, cover about 2 to 4 inches. This should amplify the amount of momentum absorbed in the "forward" direction, for waves that have already fallen out of resonance.

Todd D.

Offline TheTraveller

Today i did the first test with the Emdrive (microwave oven magnetron and cooper frustum)
The setup (magnetron and frusum) was suspended in a pendulum.
I applied power for 40 Seconds with no visible thrust. Tomorrow will will try again with the magnetron on the small side. You have any suggestion for what should be the distance from the small side?
After this i will adjust the power to the filament of magnetron and the frequency.
To fine adjust the frequency i thought i can put 2 coils over the magnetron magnets to modify the magnetic field.
My website;
http://www.masinaelectrica.com/emdrive-independent-test/



Well done.

Nicely rolled cavity walls.

Have you tried to calibrate your pendulum test rig by using a small spring scale to see how much force is needed to pull the cavity forward (toward the big end) say 1mm?

Doing this will give you some info on how much force you will need to generate to see some movement.

Maybe I should feel ashamed to propose the following calculation with all those heavy weight equations flying around, but since nobody is taking a bite at it :
a hanging swing pendulum like that has, for small deviations, a linear dependency between force (thrust) F and displacement d  F=(m*g/h)*d  where h is length of strings and m the mass of test article and g local gravity. As a first guess, with m=2kg (or more like 5kg ?) and h=2m that's in the ballpark of 10mN/mm (milliNewton per millimetre) or 10N/m. Quite remarkably similar to Eagleworks balance apparent stiffness, making this mechanical setup basically as sensitive (displacement wrt thrust wise). If a linear displacement sensor of m resolution were used it could probe into N effects, provided proper casing to isolate from drafts and good damping where strings are suspended.

Can you confirm :
- weight of system 2kg, more ?
- height of doorway, or rather length of strings about 2m ?
- graduations marks spacing about 1cm ?

The graduations marks on the video appear about 1cm apart, there is no obvious swing or displacement at power-on visible above, roughly eyeballing 1mm. That gives an upper order of magnitude bound for a thrust (if any) below 10mN/kW for this blazing fast experiment setup. Kudos, and stay safe.

Would suggest 1gf / 10mN would be a really good result from this setup.

Based on his published frustum height dimension of 228.6mm, Rf cavity resonance is 1.311GHz or 2.622GHz, which is a bit high for his magnetron. 244.7mm will give resonance at 2.45GHz. Assuming there are no fudge factors to be applied to parallel plate microwave resonance.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline deltaMass

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The RF feed is going to screw him up, sorry to say

Offline deltaMass

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Speaking of safety, do glasses exist that are transparent to visible light and attenuate microwaves?
How about clothing? - chain mail mebbe? :)

« Last Edit: 05/15/2015 12:55 AM by deltaMass »

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