Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1840441 times)

Offline deltaMass

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Here's the real problem - neither of us are professional physicists. We are both engineers (hardware/software/systems)
HA! That never stopped me or my old business partner, he didn't have a degree, but he taught computer science at Case Western, he had patents up the kazzo at Motorola and the list goes on and he even routinely debated with Brian Green and sometimes won. Ack, degree. :)

Shell
I confess I do have an honours degree in Physics (Oxford, got a place when I was 16, my biggest claim to fame I suppose) but that was the sixties and I did get a bit... distracted.  8)

I also have about 18 patents. I'm a bit of a klutz with my hands, so experimental work is somewhat uphill sledding for me. But there's nothing like strong motivation to get me bending metal and soldering (I built my first radio aged nine). If I saw some decent experimental results coming out of the superb DIY community here, I'd be clearing off the dusty workbench in two shakes of a lamb's tail; you can take that to the bank.
I'm going to do my absolute best to make you hold to that. ;) I've never backed away from a challenge.  I must admit you beat me out at 9 took me to 14-15 to do my first TV.
Shell 

PS: Yep the 60's and 70's at the UofM were kinda spacy.
An honours degree in Physics at Oxford? To me that's better than the real thing, very classy.
Shell
I'm afraid to ask what "the real thing" might be.  LOL. I would so like to avoid being banned.

Offline Rodal

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CONTINUED from http://forum.nasaspaceflight.com/index.php?topic=37642.msg1402976#msg1402976

We continue by showing the Poynting Vector Field at the circular cross-sectional yz plane at  x=97, located on the interior, between the big end and the middle of the frustum
« Last Edit: 07/11/2015 01:35 AM by Rodal »

Offline Rodal

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CONTINUED from http://forum.nasaspaceflight.com/index.php?topic=37642.msg1402997#msg1402997

We continue by showing the Poynting Vector Field at a most important circular cross-sectional yz plane at  x=149, located on the interior, between the  middle and the antenna
« Last Edit: 07/11/2015 01:55 AM by Rodal »

Offline deltaMass

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I stand with Woodward on his attitude to Shawyer. But all this is theory and to be frank I am still looking for something to make sense. I was about to say "However, Woodward would kill for Shawyer's thrust-to-power ratios" but there was a time, albeit very brief, when Woodward was measuring 15 mN of thrust from 1 KW input. He could never repeat it. Now he has Langmuir's Disease**, and is regularly down around 2 uN. My prognosis is that eventually, like the smile on the Cheshire Cat, the effect will vanish entirely. I would love to be wrong about that.

**
https://en.wikipedia.org/wiki/Pathological_science
« Last Edit: 07/11/2015 01:36 AM by deltaMass »

Offline Rodal

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Continued from http://forum.nasaspaceflight.com/index.php?topic=37642.msg1402998#msg1402998

We finish by showing the Poynting Vector Field at the circular cross-sectional yz plane at  x=208, located on the interior, near the antenna, near the small end of the frustum
« Last Edit: 07/11/2015 01:34 AM by Rodal »

Offline deltaMass

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@Rodal re. Poynting vectors: What is the total duration of each series?

Offline Rodal

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@Rodal re. Poynting vectors: What is the total duration of each series?
The total time from start of the RF feed in the Meep response analysis to the very last step is: 
 320 ( time slices) * 4.082199*10^(-11) seconds/timeSlice =
                                          = 0.013063 microseconds

Each "time slice" step is 4.082199*10^(-11) seconds/timeSlice

Duration of the total of 13 time slice steps = 53.068 *10^(-11) seconds

Last time step is at 0.013063 microseconds from the start of the RF feed ON

SI UNITS

To get SI Units from the graphs and equations in Meep units:

1) TIME:  Multiply Meep Time Slice "t" in the horizontal axis and in the formulae by the following factor:

((Total Meep Time)/(#Time Slices))*((Length Scale Factor)/(Speed of Light in Vacuum)) =
                                                                                                           =((13.054)/(320))*((0.3)/(299792458))
                                                                                                           =4.082199*10^(-11) seconds/timeSlice



ASSUMPTIONS: the validity of the following data:

Number of time slices for the total run = 320
Number of Meep time units for the total run = 13.054
Meep Length Scale factor= 0.3 meters
Meep Current (Io) = 1
« Last Edit: 07/11/2015 01:49 AM by Rodal »

Offline deltaMass

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Perhaps it would be optimal to run the simulation to equilibrium (depends on the Q of course) and then to record a couple of cycles?
(Sorry - some sort of browser glitch happened)
« Last Edit: 07/11/2015 01:49 AM by deltaMass »

Offline deltaMass

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Ah yes. Also "A journey of a thousand lightyears begins with a single Joule"

If Q is high, looks like you're getting into some serious MIPS territory.
But hey, transients can be fruitful. No argument here.
But there's a back-reaction on the antenna feed, you know.
« Last Edit: 07/11/2015 01:55 AM by deltaMass »

Offline Rodal

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Barring getting many more time steps, what I will probably do next is to compute the Stress tensor, directly from the csv files available now.

I like to see what magnitude of forces we get on each face (even if overall they should sum up to zero, although Yang wrote in her paper that she got a non-zero value for the Stress Tensor ????????  ).

In my Mathematica exact solution for standing waves I get a zero Maxwell stress tensor overall, and a zero time average Poynting vector over an integer number of periods.
« Last Edit: 07/11/2015 02:13 AM by Rodal »

Offline rfmwguy

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I stand with Woodward on his attitude to Shawyer. But all this is theory and to be frank I am still looking for something to make sense. I was about to say "However, Woodward would kill for Shawyer's thrust-to-power ratios" but there was a time, albeit very brief, when Woodward was measuring 15 mN of thrust from 1 KW input. He could never repeat it. Now he has Langmuir's Disease**, and is regularly down around 2 uN. My prognosis is that eventually, like the smile on the Cheshire Cat, the effect will vanish entirely. I would love to be wrong about that.

**
https://en.wikipedia.org/wiki/Pathological_science
Dm,
Congrats on ur self studies which have made u to a bonafide physics guru in my view. Purdue taught me aviation, life taught me rf, so understand it can be done on ur own.
Regarding langmuirs disease, this perhaps is the most important thing we all should keep in mind, when research turns to advocacy, its time to research something else. This for ur insight...and advancing beyond a forum nickname. Keep us on track and don't be afraid to plant some seeds of ur own.

Offline Ricvil

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Someone has the first 3 resonance frequencys of cavity with flat ends, and the frequency of the microwave source?
Thanks.

Perhaps this may help?

http://forum.nasaspaceflight.com/index.php?topic=36313.msg1333246#msg1333246
 Re: EM Drive Developments - related to space flight applications - Thread 2
Reply #775 on: 02/18/2015 12:32 PM
see "Frustrum modes overview 2A.pdf" attachment

Thank you very much!

I'm just looking for a possible hybrid mode on cavity. But it is not so easy.
There are some possibles candidates on Nasa's paper.
Some formulas of sensitivity can be used for adjust the dimensions of cavity and to control the frequencys.
Very cool.
By the way. In corrugated waveguides, hybrid modes have very low losses.  In cavity, perhaps  they produce more higher Q.
« Last Edit: 07/11/2015 02:20 AM by Ricvil »

Offline deltaMass

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I stand with Woodward on his attitude to Shawyer. But all this is theory and to be frank I am still looking for something to make sense. I was about to say "However, Woodward would kill for Shawyer's thrust-to-power ratios" but there was a time, albeit very brief, when Woodward was measuring 15 mN of thrust from 1 KW input. He could never repeat it. Now he has Langmuir's Disease**, and is regularly down around 2 uN. My prognosis is that eventually, like the smile on the Cheshire Cat, the effect will vanish entirely. I would love to be wrong about that.

**
https://en.wikipedia.org/wiki/Pathological_science
Dm,
Congrats on ur self studies which have made u to a bonafide physics guru in my view. Purdue taught me aviation, life taught me rf, so understand it can be done on ur own.
Regarding langmuirs disease, this perhaps is the most important thing we all should keep in mind, when research turns to advocacy, its time to research something else. This for ur insight...and advancing beyond a forum nickname. Keep us on track and don't be afraid to plant some seeds of ur own.
Thanks and back atcha for the energy you inject here. I hope to continue the ribbing about bendy pieces of wood you found on the floor for some time yet (just kidding).

For quite some time I've thought, based on rough calculations, that a lot of this bleeding edge stuff is best served (i.e. best performance, etc.) at the nano-scale with metamaterials, MEMS, etc. There has been great progress of late in that regard (metamaterials research e.g. all beginning with Veselago's seminal paper in 1964) as can be seen from, for example,  the progress in cloaking devices, which march on apace. This actually plays into the PV (Puthoff) and QV (White) space, and also into the Woodward space. Unfortunately, the amateur experimenter is SOL with such technology; it's still strictly under the provenance of well-funded research departments. Many orders of magnitude in performance improvement can be expected. Of course, the sceptic will tell you that a large number times zero is still not a lot  :)

Just wanted to throw that out there.


Offline rfmwguy

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I stand with Woodward on his attitude to Shawyer. But all this is theory and to be frank I am still looking for something to make sense. I was about to say "However, Woodward would kill for Shawyer's thrust-to-power ratios" but there was a time, albeit very brief, when Woodward was measuring 15 mN of thrust from 1 KW input. He could never repeat it. Now he has Langmuir's Disease**, and is regularly down around 2 uN. My prognosis is that eventually, like the smile on the Cheshire Cat, the effect will vanish entirely. I would love to be wrong about that.

**
https://en.wikipedia.org/wiki/Pathological_science
Dm,
Congrats on ur self studies which have made u to a bonafide physics guru in my view. Purdue taught me aviation, life taught me rf, so understand it can be done on ur own.
Regarding langmuirs disease, this perhaps is the most important thing we all should keep in mind, when research turns to advocacy, its time to research something else. This for ur insight...and advancing beyond a forum nickname. Keep us on track and don't be afraid to plant some seeds of ur own.
Thanks and back atcha for the energy you inject here. I hope to continue the ribbing about bendy pieces of wood you found on the floor for some time yet (just kidding).

For quite some time I've thought, based on rough calculations, that a lot of this bleeding edge stuff is best served (i.e. best performance, etc.) at the nano-scale with metamaterials, MEMS, etc. There has been great progress of late in that regard (metamaterials research e.g. all beginning with Veselago's seminal paper in 1964) as can be seen from, for example,  the progress in cloaking devices, which march on apace. This actually plays into the PV (Puthoff) and QV (White) space, and also into the Woodward space. Unfortunately, the amateur experimenter is SOL with such technology; it's still strictly under the provenance of well-funded research departments. Many orders of magnitude in performance improvement can be expected. Of course, the sceptic will tell you that a large number times zero is still not a lot  :)

Just wanted to throw that out there.
I hear you...graphene caught my attention some time ago and it seems to have some unusual properties relating to single layer carbon atoms and or nanotech. Levitation by light...not 100% convinced of that but interested enougn to keep my eye on it. Thinking it might interact with photons differently...may be worthy of experimenting with it on the small end plate...seems cheap enough.

Offline deltaMass

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Another little thought experiment, aimed at those that think that, in deep space, an EmDrive produces thrust that is a function of its velocity relative to some absolute inertial reference frame in some way. We start off two identical EmDrives on parallel courses (far enough part to ignore any inter-drive forces to first order). We turn them both off at some particular speed, and they both coast in unison. While still turned off, we cause one of them to traverse a region of higher drag, and so of course it slows down relative to the other one. We then turn both batteries back on. Is it a reasonable demand to expect that both drives resume acceleration with different thrusts? Of course, it is not. Does their battery "know" their current speed? Of course, it does not. Although both batteries are emptied to the same extent, the speeds of the two drives are different! Now repeat the experiment, this time by booting one in the backside (say with a powerful laser) while both batteries are again off. Ask the same two questions after they both resume thrusting. The answers will be the same. There can be no dependency on speed for the thrust developed by the drive.

Where does that leave us? With the potential for over-unity, of course! The value of k [N/W] is a fixed number descriptive of the EmDrive design; it is not a dynamical quantity. The acceleration will be constant as long as the battery lasts, or unless we feed back excess power to self-sustain this perpetual motion machine of the first kind. The drive obeys special relativity of course, and can never exceed light speed.

It's not a pretty sight, but that's how the physics logically must be.

Offline TheTraveller

The Traveller's EMDrive independent Force verifier program

Would appreciate a email from those who are interested in verifying the Force generation from my 2.45GHz variation of the SPR Flight Thruster.

After I complete and publish my series of experimental tests on the EMDrive, I plan on making around 6 more EMDrive systems, complete with 100W Rf amp, frequency tracking control system, BlueTooth data logging and control system, plus the PC software to control the system.

Expected Force generation, at 100 Ws, should be around 60mN or 6gf.

Those who are willing to replicate my rotary test setup, will be considered to have sent to them, at my expense, all the above hardware for independent verification of the Force generation.

After the independent tester has verified and reported the Force generation, if they wish to keep the hardware I have supplied, it will be available to them at my cost.

If you wish to enquire further about this independent verification program, please email me:

"The Traveller E M D at g mail dot com" Of course remove the spaces, at = @ and dot = .
« Last Edit: 07/11/2015 06:03 AM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline TheTraveller

Another little thought experiment, aimed at those that think that, in deep space, an EmDrive produces thrust that is a function of its velocity relative to some absolute inertial reference frame in some way. We start off two identical EmDrives on parallel courses (far enough part to ignore any inter-drive forces to first order). We turn them both off at some particular speed, and they both coast in unison. While still turned off, we cause one of them to traverse a region of higher drag, and so of course it slows down relative to the other one. We then turn both batteries back on. Is it a reasonable demand to expect that both drives resume acceleration with different thrusts? Of course, it is not. Does their battery "know" their current speed? Of course, it does not. Although both batteries are emptied to the same extent, the speeds of the two drives are different! Now repeat the experiment, this time by booting one in the backside (say with a powerful laser) while both batteries are again off. Ask the same two questions after they both resume thrusting. The answers will be the same. There can be no dependency on speed for the thrust developed by the drive.

Where does that leave us? With the potential for over-unity, of course! The value of k [N/W] is a fixed number descriptive of the EmDrive design; it is not a dynamical quantity. The acceleration will be constant as long as the battery lasts, or unless we feed back excess power to self-sustain this perpetual motion machine of the first kind. The drive obeys special relativity of course, and can never exceed light speed.

It's not a pretty sight, but that's how the physics logically must be.

The accelerating EMDrive obeys A = F/M. It only knows generated Force doing Work accelerating a Mass. The Mass's Velocity and KE mean nothing to the accelerating EMDrive.
« Last Edit: 07/11/2015 05:55 AM by TheTraveller »
"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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A design exercise: the design of an EmDrive spacecraft. The core idea is that the whole thing is propellantless, and therefore the craft will contain two types of EmDrive; one type being a set of rotary devices operating at overunity, and thus able to supply continuous free power to the second set of drive types, which fill the role of the main thrusters. Sadly we cannot exploit the overunity characteristics of the main drives, but on the other hand that might be seen as just plain greedy, since we already have free energy forever to accelerate the ship and to decelerate it too - all without propellant.

Ad Astra indeed.

Offline TheTraveller

A design exercise: the design of an EmDrive spacecraft. The core idea is that the whole thing is propellantless, and therefore the craft will contain two types of EmDrive; one type being a set of rotary devices operating at overunity, and thus able to supply continuous free power to the second set of drive types, which fill the role of the main thrusters. Sadly we cannot exploit the overunity characteristics of the main drives, but on the other hand that might be seen as just plain greedy, since we already have free energy forever to accelerate the ship and to decelerate it too - all without propellant.

Ad Astra indeed.

The universe may just have an, untold as of yet, Gotcha Effect, that we will never experience until we try to go overunity.

With a really good and careful build I may be able to get to 1.0N/kW (0.1N/100W in reality) with a high quality silver/gold internal layer and high precision frequency tracking system but that is then about the limit for non superconducting cavities.

Would be really delighted to learn your thoughts on how to push that EMDrive into predicted overunity so we can see what happens??????
« Last Edit: 07/11/2015 06:13 AM by TheTraveller »
"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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A design exercise: the design of an EmDrive spacecraft. The core idea is that the whole thing is propellantless, and therefore the craft will contain two types of EmDrive; one type being a set of rotary devices operating at overunity, and thus able to supply continuous free power to the second set of drive types, which fill the role of the main thrusters. Sadly we cannot exploit the overunity characteristics of the main drives, but on the other hand that might be seen as just plain greedy, since we already have free energy forever to accelerate the ship and to decelerate it too - all without propellant.

Ad Astra indeed.

The universe may just have a, untold as of yet, Gotcha Effect, that we will never experience until we try to go overunity.

With a really good and careful build I may be able to get to 1.0N/kW with a high quality silver/gold internal layer and high precision frequency tracking system but that is then about the limit for non superconducting cavities.

Would be really delighted to learn your thoughts on how to push that EMDrive into predicted overunity so we can see what happens??????

Let me delight you, then  8)

As already posted, there are two breakeven speeds.

The lower one, vP, occurs at speed 1/k m/s (for k=0.001 N/W, vP=1 Km/s) and is the speed above which more power is produced than is being input. I call it the "power breakeven" speed.

The higher one, vE, occurs at speed 2/k m/s (for k=0.001 N/W, vE=2 Km/s) and is the speed above which the kinetic energy exceeds the total energy input up to that time. I call it the "energy breakeven" speed, and it assumes constant acceleration up to vE.

There will be a generator coaxial with the rotary thruster, and there is an overall efficiency figure for the system, being a function of generator efficiency, electronic power conversion efficiency and mechanical losses. If this is for example 50%, then you will need to double both the above speeds (they become 2 Km/s and 4 Km/s). An added complication is that in practice the overall rotary efficiency depends on the angular frequency, so an exact mathematical treatment is not possible without knowing the details of the efficiency as a function of angular speed. But to first order we can approximate the efficiency with a single figure.

It is the effective power breakeven speed  (1/e) * vP that's of interest (e = fractional efficiency, e.g. 0.5). For example, with e=50%=0.5 and k = 0.001 N/W, we need at least 2 Km/s effective speed.

As a practical matter in a terrestrial lab, this is problematic.  The speed of sound at sea level is about 340 m/s and so we are calling for about Mach 2000/340 ~= Mach 6!

For a 0.5 metre radius arm, this corresponds to an angular frequency of f = v/ (2*PI*r) ~= 640 Hz = 3,800 rpm. The centrifugal acceleration is v2/r = 8*106 m/s2, or a little less than 1 million gee!! That is out of the question, and so a larger radius arm would be needed, and a big vacuum chamber to contain it. This is at the limit of what can be done in a  terrestrial lab with lots of funding, so I doubt you'll be able to try this out.

Something just within the realm of possibility (??) would have say 4,000 gee centrifugal acceleration for that 2 Km/s tangential velocity. This corresponds to a radius arm of length 100 metres! That's one mondo vacuum chamber. And "interesting" mechanical engineering challenges too.

Everything hinges on the achievable N/W k-value.  If something like 0.001 N/W is indeed the practical limit, then power generation is going to have to be space-based. Out there, there is no problem with higher speeds, and the radius arm can be made very long to lower the gee-stresses.

« Last Edit: 07/11/2015 07:19 AM by deltaMass »

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