Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1839529 times)

Offline deltaMass

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I seem to be operating in Blurt Mode today. Here's another blurt:

If they can take an espresso machine to ISS, why not an EmDrive for microgee testing?

No doubt the expresso machine had to pass a complete battery of tests to certify it as spaceflight hardware.  An EM-Drive would fail the emi tests for starters.   Maybe a new improved expresso machine could be designed that used a magnetron to heat the beans and could double as a clandestine EM-Drive test.
;D
How about the Vomit Comet? Is 30 seconds time enough to positively identify a turkey?

ETA Don't they already have a microwave oven aboard ISS to heat their food and drink?
« Last Edit: 08/01/2015 12:00 AM by deltaMass »

Offline Rodal

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A comment on simulations from elsewhere. Tagline: BEWARE!  ...
Well, there is a huge difference, dare I say, between someone that was awarded S.B., S.M. and Ph.D. degrees from MIT all involving numerical analysis by Finite Difference and Finite Element methods, theory and experiments, has won awards, author of several such computer programs and has been involved in R&D for NASA, DoD, and multinational private companies and what you are discussing .  Just saying :)
« Last Edit: 08/01/2015 12:31 AM by Rodal »

Offline deltaMass

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A comment on simulations from elsewhere.

Tagline: BEWARE!

...
Well, there is a huge difference, dare I say, between someone that was awarded S.B., S.M. and Ph.D. degrees from MIT all involving numerical analysis by Finite Difference and Finite Element methods, theory and experiments, has won awards, author of several such computer programs and has been involved in R&D for NASA, DoD, and multinational private companies and what you are implying.  Tagline: BEWARE of what you are comparing.   Just saying :)
Unfortunately (or fortunately, depending) you personally were not involved in the Cannae simulations, which was what this was about (sorry for not having indicated the context). Perhaps there's a way for you to get involved in that process?

This all started following my remarks about Lorentz force and Cannae in particular
« Last Edit: 08/01/2015 12:11 AM by deltaMass »

Offline BL

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Postulating that Shawyer is right when he says that EmDrives will produce thrust proportional to drive power and Q, those predicting wonderful things when thrusters with Qs in the 1e9 range become available may want to curb their enthusiasm a bit.

Consider Shawyers latest:  an eight cavity thruster in a 10 ton vehicle, operating at 915 MHz, with the drive power being cycled to each cavity every 220 ms.   I. e., each cavity has to produce enough thrust to lift the vehicle, but it only has to do it for 27.5 ms every 220 ms.  Shawyer says that he is adding piezoelectric compensation to change the cavity size by up to 22 microns to account for Doppler shift.  I suspect that Doppler shift will be the least of his problems.

A Q of 1e9 @ 915 MHz implies a bandwidth of slightly less than 1 Hz.  Does anyone think that a cavity sized for resonance at 915 MHz being hit with with 10 ton impulses every 220 ms with a duty cycle of 12.5% will be mechanically stable to better than 1e9, never mind the Doppler compensation?  What will happen to a precision oscillator mounted on a platform that is being hammered with 10 ton 4.5 Hz impulses at 8 different locations?  Do you think that it will be mechanically stable enough to keep all of its energy in a less than 1 Hz bandwidth while the 8 thruster engine is running?

Even really good precision signal sources begin to resemble dirty ol magnetrons when looking at their spectral content in sub-hz bandwidths around the carrier.  And that is without being subject to any mechanical vibration, such as could be expected on a spacecraft being subjected to 10 ton impulses at a 4.5 Hz rate at eight different locations.

Even if Shawyer is right and one of our DIYers report confirmed thrust from their frustum, it will be awhile before we will see 10 ton spacecraft wafting into the stratosphere, lifted by superconducting EmDrive thrusters.

Offline Rodal

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A comment on simulations from elsewhere.

Tagline: BEWARE!

...
Well, there is a huge difference, dare I say, between someone that was awarded S.B., S.M. and Ph.D. degrees from MIT all involving numerical analysis by Finite Difference and Finite Element methods, theory and experiments, has won awards, author of several such computer programs and has been involved in R&D for NASA, DoD, and multinational private companies and what you are implying.  Tagline: BEWARE of what you are comparing.   Just saying :)
Unfortunately (or fortunately, depending) you personally were not involved in the Cannae simulations, which was what this was about (sorry for not having indicated the context). Perhaps there's a way for you to get involved in that process?
Your warning is a good one.  A powerful computer program is a loaded gun: you better be an expert on how to use them for your own and others safety.  Particularly when used to make predictions.

As an example: the issue with the foam impact on the Space Shuttle.  I was dismayed to hear how NASA handled the foam impact problem on the Shuttle's wing edge and how Managers were discounting it as an issue, all based on really bad engineering analysis of the foam impact problem.
« Last Edit: 08/01/2015 12:32 AM by Rodal »

Offline deltaMass

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@TT:
There's a video of Shawyer's device slowly rotating (you've posted it many times; you know the one). There's also a graph of power and thrust over time (you've also posted many times).
Are you sure that they go together?

Reason I ask is that the speed looks about constant - there is little discernable acceleration at all.

Use the YouTube video. Run it at 1/4 speed. Record the video seconds between the pointer hitting each mark. Can use freeze frame to do this.

You can also import the video from www.emdrive.com and use a video software package to determine the time between the pointer hitting each mark.

I measured the time between each of the 15 marks and the middle 0.5 estimated marks on the table and got the attached velocity curve. This is not the entire acceleration period, just the pointer moving right over the 15 marks on the table.
@TT:
Once more with feeling: please indicate the semantics (position, velocity, time, etc.) of each axis and the units (m/s, sec, etc) used for those semantics.
I am trying to make sense of your graph but don't know what I'm looking at.
« Last Edit: 08/01/2015 12:22 AM by deltaMass »

Offline aero

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@SeeShells and @Rodal,
The data you are referring to was something I generated after reading a post/paper by Dr. Rodal in which he discussed extending the Brady frustum, using the same big end diameter and the same taper angle, but extending until the small end diameter equalled 25% of the big end diameter. The views posted are for the start of the cavity, power on until some cycles later. We remarked at the time about the changing range of the signal causing color changes, but no one realized that I had discovered the first step in inventing the "flashy light thingee" used by the Men in Black.

I have used time today to re-run that model generating what has become rather standard upload data, both csv files and png views, here:

https://drive.google.com/folderview?id=0B1XizxEfB23tfkZVbi1MY2RQZmVkeEVHUmVfQkc3UEdlVkdOVXZENmFYbmg4czJUd1lqcDg&usp=sharing

Read the data request file, where I blamed Rodal for asking for the data. I copied some data from my meep run log into the file giving basic cavity and run information. I did not use run logs back in mid June but it is the same model so today's run log data should be the same as was ran back in  June. I don't recall where the 2.14 GHz center drive frequency number came from, perhaps it was Harminv.

In any case, I hope this data tells us something, and Dr. Rodal, the complete set of 14 time slice csv files are there so you now have the data to calculate stresses. I'd be interested in seeing the result. Looks to me like zero force on the small end, but appearances can be deceiving.
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Offline Rodal

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@SeeShells and @Rodal,
The data you are referring to was something I generated after reading a post/paper by Dr. Rodal in which he discussed extending the Brady frustum, using the same big end diameter and the same taper angle, but extending until the small end diameter equalled 25% of the big end diameter. The views posted are for the start of the cavity, power on until some cycles later. We remarked at the time about the changing range of the signal causing color changes, but no one realized that I had discovered the first step in inventing the "flashy light thingee" used by the Men in Black.

I have used time today to re-run that model generating what has become rather standard upload data, both csv files and png views, here:

https://drive.google.com/folderview?id=0B1XizxEfB23tfkZVbi1MY2RQZmVkeEVHUmVfQkc3UEdlVkdOVXZENmFYbmg4czJUd1lqcDg&usp=sharing

Read the data request file, where I blamed Rodal for asking for the data. I copied some data from my meep run log into the file giving basic cavity and run information. I did not use run logs back in mid June but it is the same model so today's run log data should be the same as was ran back in  June. I don't recall where the 2.14 GHz center drive frequency number came from, perhaps it was Harminv.

In any case, I hope this data tells us something, and Dr. Rodal, the complete set of 14 time slice csv files are there so you now have the data to calculate stresses. I'd be interested in seeing the result. Looks to me like zero force on the small end, but appearances can be deceiving.

Where is the antenna (dipole?) located  what orientation and how big is it?

Big diameter =  meters
Small Diameter = meters
Location of Big base =    row and column
Location of Small base =  row and column
Total Meep run time =
Total Number of Time Slices =
Total Number of Finite Difference time steps =



Thanks
« Last Edit: 08/01/2015 12:41 AM by Rodal »

Offline frobnicat

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@zellerium: the "cardboard-like square part" is a thin piece made of mica which covers the end of the waveguide in a microwave oven. Mica (as well as white Teflon) is indeed transparent to microwaves. It lets the EM waves pass through it but protects the food from being impregnated by some undesirable substance that may be emitted from the magnetron cavity, like oil or metallic particles.

This is a thought to EmDrive DIYers: maybe it is a good idea to insert a Teflon or Mica sheet in the waveguide to protect the interior of the cavity from those substances, in the same manner as food is protected in the oven.

@Rodal, flux capacitor and all other experts:
I was thinking about the glimmer plate inside the microwave cooking oven and MW sputtering technique. Without such a plate how many metal ions would enter the cavity? Is it possible that the ions (with high velocity a.k. relativistic mass times rest mass) cause the trust while the EM-field inside the cavity give them preferred direction to a single end plate?

@flux capacitor
Thanks for surprising to Tajmar. ;D
Here one can see how important the peer review process really is!

Is there really no one with ideas about (blue text) ? ???

Yes, I had an idea, which was to "like" your post, which meant that I agree with you that this is another possible source of thrust.  :)
I know about your like :)
But the magnitude of this effect is not really clear for me at the moment, how many mass(particles/s will be emit) using a standard magnetron? That's what i ask for.

Maybe it's a little less or it's not? And with regard to thrust after 'Power off' in several experiments, i am not sure about the relevance.

I disagree with this as a possibility for reported thrust results, not that much on magnitude arguments but because, again, this is a closed device : a given significant thrust (say 20N) can be obtained either by a "high" mass flow at low velocity ( 2g/s*.01m/s=20N ) or by a low mass flow at high velocity typical of MW sputtering ( 20g/s*1km/s=20N ). 20g/s for 100s = 2mg, about .2mm3 worth of removed material at copper density. I must say I don't know exactly how much energetic and where (what material) would be accidentally sputtered by a magnetron, let's say it could go to a few hundreds of eV, velocities above 5km/s, removed material could stay below .1mm3 for some amount of time while still thrusting at 20g/s (notice that microwave oven magnetrons operated at nominal conditions don't wear near that fast, but they are not supposed to be driving a high Q cavity...).

So maybe stretching numbers a little bit, a sputtering magnetron could possibly thrust for many minutes without noticing wear or significantly altered performances. But, back to the comparison high flow low velocity vs low flow high velocity : both can impart same thrust, but this is assuming the "exhaust" is not yet interacting with the limits of the rigid closed system as a whole, since we are exhausting inside a box that is attached to the thruster ! For high velocity this occurs too soon.

Let's take such a reaction thruster attached to (and exhausting reaction mass into) a box of 1m span. With 20g/s mass flow 1km/s we do record an apparent net thrust overall (system wide) of 20N but only for 1ms. Then, assuming constant flow, this net thrust goes to 0 exactly : we are still sputtering and eroding material but the momentum gained at emission is exactly compensated by the opposite momentum lost at the wall where exhaust ends its course. Obviously trying to cheat by playing around with reorientations of path, magnetic mirrors and such, is futile (as any change of path of exhaust must recoil on what is causing the change of path, whatever the mean). Then when the process of emission stops, we would observe an apparent net thrust overall of -20N (opposite direction as for the power on) for 1ms again.

On the other hand, if a magician decided to play a trick, it could be relatively straightforward to send a flow of 2g/s at .01m/s (say, by pumping some fluid), that could impart an apparent net thrust (as observed from the outside) of 20N during 100s. This apparent thrust would be perfectly well behaved, it could accelerate the system if the system is free to accelerate, it could push against a spring and maintain a force while being static. This is Newtonian propellantless thrust in all its glory. But this is only momentum hidden by a container : after 100s, the box will pay back by thrusting -20N for 100s. Spatial extent 1m, secretly transferred mass 200g (offset of CoM will remain unnoticed if box weighs a few kgs). Advice to the magician : 1 minute of demonstration, then say that if it can thrust for 1 minute then surely it could also thrust for years on (only a matter of engineering and $). Make sure the device is no longer on the scale after 1 minute of demo, put it back in an IP box.
« Last Edit: 08/01/2015 01:00 AM by frobnicat »

Offline aero

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@SeeShells and @Rodal,
The data you are referring to was something I generated after reading a post/paper by Dr. Rodal in which he discussed extending the Brady frustum, using the same big end diameter and the same taper angle, but extending until the small end diameter equalled 25% of the big end diameter. The views posted are for the start of the cavity, power on until some cycles later. We remarked at the time about the changing range of the signal causing color changes, but no one realized that I had discovered the first step in inventing the "flashy light thingee" used by the Men in Black.

I have used time today to re-run that model generating what has become rather standard upload data, both csv files and png views, here:

https://drive.google.com/folderview?id=0B1XizxEfB23tfkZVbi1MY2RQZmVkeEVHUmVfQkc3UEdlVkdOVXZENmFYbmg4czJUd1lqcDg&usp=sharing

Read the data request file, where I blamed Rodal for asking for the data. I copied some data from my meep run log into the file giving basic cavity and run information. I did not use run logs back in mid June but it is the same model so today's run log data should be the same as was ran back in  June. I don't recall where the 2.14 GHz center drive frequency number came from, perhaps it was Harminv.

In any case, I hope this data tells us something, and Dr. Rodal, the complete set of 14 time slice csv files are there so you now have the data to calculate stresses. I'd be interested in seeing the result. Looks to me like zero force on the small end, but appearances can be deceiving.

Where is the antenna (dipole?) located  what orientation and how big is it?

Big diameter =  meters
Small Diameter = meters
Location of Big base =    row and column
Location of Small base =  row and column
Total Meep run time =
Total Number of Time Slices =
Total Number of Finite Difference time steps =



Thanks

Did you not get access to this folder?
https://drive.google.com/folderview?id=0B1XizxEfB23tfkZVbi1MY2RQZmVkeEVHUmVfQkc3UEdlVkdOVXZENmFYbmg4czJUd1lqcDg&usp=sharing
The image shows the general location of the antenna, near the big end side wall laterally oriented. The text file includes the specific location as well as the other information you requested. You can double click on the text file to open it or you can download it and read it with your own text editor. Or if you want, I can post it here, if fact, I will. It is attached. But do try to look at the uploaded text file, because if you can't read it then something is not working right and needs to be fixed.
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Offline martinc

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on some more reading your were right, we can't just modify newtonian or einsteins theories or at least, how these two have been combined into the "current working theory" consensus. then there'ss quantum mechanics and string theory. the scientific way is to keep with the tried and true way of working with data. relativity has been working for 100 years and used on gps to account for space/time warp of earth on the clocks :)

regarding dark matter and expansion: these are results of the early experiments i saw a sky map of dark matter from japan today. i don't know how they did it. the only other i saw was gamma ray of the whole milky way but this was a sky map around individual galaxies
i am thinking that maybe dark matter is anti-matter and we somehow orbit each other without interacting. but i've read people say these are two different things. (which complicates things further in my mind as another category of matter to figure out)
or maybe dark matter is pure gravity and that's why we can't see it

any change to relatvitiy has to match all experiments data as good as einsteins and be given in equations
i love listening to physics lectures and being mesmerised by the physics and the language of the tensors and the equations that are the most baffling. this is not algebra or statistics but some sort of geometrical formula to space/time.

i think its way too soon to make big changes cause which one do you pick? there's tons of competing and completly different theories and new ones come out all the time. i wonder if quantum mechanics is facing similar situation i want to get into that later after focusing on just relativity. that and electromagnetism is pretty amazing stuff

we know the universe is a strange place and full of complete suprises at times. . in early age of electricity and radio and experiment tech, in this environment some dude called einstine took a huge leap forward with conceptual stuff that actually works and matches the data from every experiment like gravity probe b and all the latest experiments. the heaviest lectures i found pulled up einsteins equations by far the most often and quite a bit of banter and questions with loads of challenges and rebuttals.

so albert is still kicking butt. any new theory will be some refinement of relativity maybe with quantum mechanics string theory is another quite possible one or both together
 
there's all sort of things predicted in relativity like black holes that we later found (another win) and worm holes probably will be next to be discovered - i was just thinking, maybe black holes are all linked via wormholes and form a network. if this was gravitational, probably pulling the matter back to a central location. these wormholes probably have mass. simply too much material inside not to warp the space around them

in that case could dark matter simply be gravity? knowing einstein this network will not be in our reference frame and probably receding in time also so we can't go looking for it.  i'm gonna see what theories are out there on wormholes.  the em drive sure is bringing a lot of people into physics

Offline Rodal

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...I disagree with this as a possibility for reported thrust results, not that much on magnitude arguments but because, again, this is a closed device ...
And how do you know that this is such a hermetically closed device ???
In the first thread we were discussing the possibility of warm air being exhausted as a jet.  You conducted calculations.  What has happened as of late that you are so convinced now that this is a hermetically closed device that we cannot consider this as an exhaust???
« Last Edit: 08/01/2015 01:38 AM by Rodal »

Offline frobnicat

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...
2) His remarks about buying the microwave oven and the cooking oil were in jest.  I doubt he had the time to do that personally.  Maybe the guy that is on vacation was the one that bought the cooking oil.
...

Isn't putting cooking oil in an experiment involving vacuum asking for troubles ? I mean, it likely is not low vapour pressure (like would be vacuum pump oil), has high water content...

Offline Rodal

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...
2) His remarks about buying the microwave oven and the cooking oil were in jest.  I doubt he had the time to do that personally.  Maybe the guy that is on vacation was the one that bought the cooking oil.
...

Isn't putting cooking oil in an experiment involving vacuum asking for troubles ? I mean, it likely is not low vapour pressure (like would be vacuum pump oil), has high water content...
Isn't purposely testing an EM Drive with a Q lower than 50 and with a huge bloody hole from a huge bloody waveguide asymmetrically placed on one side also asking for trouble ?  It is par for the course...
« Last Edit: 08/01/2015 01:44 AM by Rodal »

Offline rfmwguy

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NSF-1701 2nd static thermal test is done:


Offline deltaMass

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After seeing that vid I'm adding another artifact candidate - steam jet.

Offline rfmwguy

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After seeing that vid I'm adding another artifact candidate - steam jet.
I agree, that's why I want to do a lot of thermal testing of hotspots. The machine screw head was way hotter than surrounding metal. I suspect some rf leakage between copper clad end plates. Simple fix I'll mess with over the weekend. Thermal issues need to be addressed well ahead of torsion or balance testing imho.

Offline frobnicat

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...I disagree with this as a possibility for reported thrust results, not that much on magnitude arguments but because, again, this is a closed device ...
And how do you know that this is such a hermetically closed device ???
In the first thread we were discussing the possibility of warm air being exhausted as a jet.  You conducted calculations.  What has happened as of late that you are so convinced now that this is a hermetically closed device that we cannot discuss this exhaust???

Basically the idea (sorry if I misunderstood) is we could have a kind of ion gun shooting its exhaust from the magnetron to within the cavity. Granted those cavities (used so far) may not be hermetically closed, but they are clearly not wide open somewhere, so unless there is a mechanism that would specifically drive the ions through a tiny opening to the outside (where they can play their role of fully thrusting exhaust, by saying farewell to the rigid system), those ions would, for their immense majority, just crash on the walls.

So, my argument is : within the hypothesis that there is no mechanism that would specifically drive/funnel the ions through a tiny opening to the outside, and let them escape at their high velocity, momentum gained at emission is lost at impact, and at high velocities there is not enough time between emission and impact to record pseudo thrust (transfer of mass within the system) for significant duration after power on.

There is no question that cavities under discussion are rarely hermetically closed (especially those that are involved in experiments in vacuum) and that any leaking material will record as thrust. Basically what I was saying is that it is not sufficient to have a high specific impulse thrusting mechanism within the box to explain the results as action/reaction (while still having erosion/wear low enough to go unnoticed). Do you really think that MW sputtering that might occur in the magnetron could specifically be the cause for a significant flow of still high velocity ballistic ions after leaving through cracks ? Maybe I sounded a bit more definitive than I should, but that seems a bit of a stretch, almost like we had a two stage ion thruster by accident. Check my numbers but I think that at less than 1km/s ejection speed outside the system, mass is eroded too fast to go unnoticed, if thrust of a few 10s of N for 100s of seconds is to be obtained by eroding material.
« Last Edit: 08/01/2015 02:19 AM by frobnicat »

Offline WarpTech

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@SeeShells and @Rodal,
The data you are referring to was something I generated after reading a post/paper by Dr. Rodal in which he discussed extending the Brady frustum, using the same big end diameter and the same taper angle, but extending until the small end diameter equalled 25% of the big end diameter. The views posted are for the start of the cavity, power on until some cycles later. We remarked at the time about the changing range of the signal causing color changes, but no one realized that I had discovered the first step in inventing the "flashy light thingee" used by the Men in Black.

I have used time today to re-run that model generating what has become rather standard upload data, both csv files and png views, here:

https://drive.google.com/folderview?id=0B1XizxEfB23tfkZVbi1MY2RQZmVkeEVHUmVfQkc3UEdlVkdOVXZENmFYbmg4czJUd1lqcDg&usp=sharing

Read the data request file, where I blamed Rodal for asking for the data. I copied some data from my meep run log into the file giving basic cavity and run information. I did not use run logs back in mid June but it is the same model so today's run log data should be the same as was ran back in  June. I don't recall where the 2.14 GHz center drive frequency number came from, perhaps it was Harminv.

In any case, I hope this data tells us something, and Dr. Rodal, the complete set of 14 time slice csv files are there so you now have the data to calculate stresses. I'd be interested in seeing the result. Looks to me like zero force on the small end, but appearances can be deceiving.

Where is the antenna (dipole?) located  what orientation and how big is it?

Big diameter =  meters
Small Diameter = meters
Location of Big base =    row and column
Location of Small base =  row and column
Total Meep run time =
Total Number of Time Slices =
Total Number of Finite Difference time steps =



Thanks

@Rodal,

When you analyze this data. Is there "any" difference in the frequency between the big end and the small end? Amplitude is one thing, but in order for any of these thrust equations to work, there needs to be a shift in the frequency at which it oscillates between the axis and the tapered walls.

I've been thinking, another way to power these things may be with a spark-gap, rather than a magnetron. With a spark gap, the natural resonant frequency should occur automatically, due to the impulse response. Wouldn't it? It can also deliver a lot of power without this VSWR crap that can destroy the amplifier.

Hey! I'm not an mw engineer. I do power electronics. Spark gaps, transformers and Megawatts is how I roll! 
Todd

Offline Devilstower

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@rfmwguy since it appears you can't run continuously for a prolonged period without reaching a critical heat regime, what's the plan?

Are you going to implement a cooling system so you can run continuously, or used a reduced power level that involves the magnetron cycling off and on? If the later, how would you untangle the ramp-up, ramp-down seen in previous experiments from the magnetron cycles? It would see, to be difficult under those circumstances to have a very clean relationship between system on/off and measured thrust.

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