Author Topic: EM Drive Developments - related to space flight applications - Thread 10  (Read 1635398 times)

Offline Monomorphic

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a few remarks concerning the idea of 3dprinting :

-printing in quarter parts is not a good idea, because of the increased warping, due to not being a full circular object. The thermal tension in a fully circular object cancel each other out (more or less). Printing only a quarter will make it difficult to get all piece join up nicely.

-secondly, you might want the outside of the part designed as a flat part, so you can print it without the need for supports. You want to print this with the inside upwards.

-You'll need to pay special attention to where you put your seams (the points your printhead moves from layer to layer)

-with FDM fillament printing, always expect a small hick-up or imperfection somewhere, so you'll need to think about post processing too.

-I'm worried about the thermal stability when the EMdrive is operational as most thermoplastics tend to deform easily when they reach  100° C.

-As last hint , regardless my above concern, I'd suggest printing with PETG to minimize thermal warping. PLA tends to be brittle (fastening bolts might crack it) and ABS is notorious for thermal warping...

-to get a good surface finish, I suggest using a spray car putty and some fine sanding paper. then coat it with a conductive paint, then copper plate it...

These are all very good points. Thank you. The way I see it, this can go several ways. The most obvious route is to 3D print the parts and simply cover them with EMI shielding copper conductive adhesive tape. Alternatively, one could 3D print, sand, and then copper plate. Yet another option is to 3D print and then use a process like the Virtual Foundry (http://www.thevirtualfoundry.com/) to make solid copper parts. The last option, and the best route in my opinion, is to 3D print wax copies of the end plates and then use the lost wax process to create parts which are then machined to exact specifications.
« Last Edit: 06/05/2017 12:43 pm by Monomorphic »

Offline Mark7777777

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Harbin Institute of Technology has applied for two emdrive patents.

I did try to convert the PDFs to English by uploading them to google translate. It didn't do it. If anyone else has other means of doing it ...

Offline Star One

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Harbin Institute of Technology has applied for two emdrive patents.

I did try to convert the PDFs to English by uploading them to google translate. It didn't do it. If anyone else has other means of doing it ...

Does that usually work, not the biggest expert on translating PDFs?

Offline AnalogMan

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Harbin Institute of Technology has applied for two emdrive patents.

I did try to convert the PDFs to English by uploading them to google translate. It didn't do it. If anyone else has other means of doing it ...

Managed to find machine translations for both patents:

CN 105790717 A A microwave-based adaptive tuning system for a non-working microwave thruster and a microwave source adaptive tuning method using the system

http://www.google.com/patents/CN105790717A


CN105775171A Propelling system assisting in reducing weight of propelling system and changing degree and direction of thrust

http://www.google.com/patents/CN105775171A

[Edit: added second patent link]
« Last Edit: 06/05/2017 01:15 pm by AnalogMan »

Offline ThatOtherGuy

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a few remarks concerning the idea of 3dprinting :

-printing in quarter parts is not a good idea, because of the increased warping, due to not being a full circular object. The thermal tension in a fully circular object cancel each other out (more or less). Printing only a quarter will make it difficult to get all piece join up nicely.

-secondly, you might want the outside of the part designed as a flat part, so you can print it without the need for supports. You want to print this with the inside upwards.

-You'll need to pay special attention to where you put your seams (the points your printhead moves from layer to layer)

-with FDM fillament printing, always expect a small hick-up or imperfection somewhere, so you'll need to think about post processing too.

-I'm worried about the thermal stability when the EMdrive is operational as most thermoplastics tend to deform easily when they reach  100° C.

-As last hint , regardless my above concern, I'd suggest printing with PETG to minimize thermal warping. PLA tends to be brittle (fastening bolts might crack it) and ABS is notorious for thermal warping...

-to get a good surface finish, I suggest using a spray car putty and some fine sanding paper. then coat it with a conductive paint, then copper plate it...

These are all very good points. Thank you. The way I see it, this can go several ways. The most obvious route is to 3D print the parts and simply cover them with EMI shielding copper conductive adhesive tape. Alternatively, one could 3D print, sand, and then copper plate. Yet another option is to 3D print and then use a process like the Virtual Foundry (http://www.thevirtualfoundry.com/) to make solid copper parts. The last option, and the best route in my opinion, is to 3D print wax copies of the end plates and then use the lost wax process to create parts which are then machined to exact specifications.

Well, maybe there are alternatives, check this stuff  ;)

[edit]

Or, you may always go for the plastic printing, as long as someone (no idea here, sorry) finds a way to apply this to the printed parts

[edit #2]

found something here - not sure it may fit, though

« Last Edit: 06/05/2017 01:52 pm by ThatOtherGuy »

Offline xyzzy

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I'm pretty deep "in the weeds" right now. I will conduct a series of low powered tests (2.5W) this week. Then I will work on incorporating the new 30W amplifier.

I have also been working on STL files for 3D printing the spherical endplates. Due to the large size and tight tolerances, I have had to cut the end plates into fourths so that it can be printed using the prusa i3 mk2 platform.

Are you sure you want to go that route? From what 3d printed parts I've seen, they were never exact.

The couple of times that I happened to see the "work" of an older (some 6-7 years) industrial type machine that must have cost a fortune when it was new and was owned by a large company, I found it impressively unimpressive. Straight vertical elements were askew, no two seams of a sectioned part would really fit together and the dimensional tolerances of the final part were such that no self-respecting mechanical engineer would ever dare to utter that term in this context. Granted, the machine was an early generation, no longer new, and becoming increasingly flakey. It must have seen better days - otherwise nobody would have paid much for it, but still it was difficult to imagine it ever being useful for precision parts.

If anything, plastic filament 3d printing looks to me more like the first coarse production step, to be followed by the famous universal finishing approach "file to fit, sand to suit, hammer home", only without the hammering, the parts being fragile.

« Last Edit: 06/05/2017 02:06 pm by xyzzy »

Offline Monomorphic

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CN105775171A Propelling system assisting in reducing weight of propelling system and changing degree and direction of thrust

This looks like an emdrive based reaction control system.

Offline xyzzy

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CN105775171A Propelling system assisting in reducing weight of propelling system and changing degree and direction of thrust

This looks like an emdrive based reaction control system.

Yep, seems so. And the other patent describes a force locked control loop. The circuit diagram inside is an oscillator, apparently with some FM capability (by "pulling" a crystal resonator). The google-translated text describes the EM drive being attached to a force sensor that provides a signal to a controller, which in turn controls the oscillator.

P.S. Apparently they envision an early stage prototype satellite. The coarse frequency selection steps are described to be remotely commanded from ground control (presumably in discrete steps), based on the (presence or absence of force) feedback from the force sensor. The fine frequency control does not seem clearly described, but I think that is what the FM is for. This would need reasonably fast realtime (PLL-like) control only realistically achievable with an on board controller.

P.P.S. The "invention" does not seem to amount to much - it looks like a first step going from a constant frequency non-adjustable RF source to one that can be stepped through a series of bands by remote commands. Trivial patents, anyone? Almost as if the inventor designed TV tuner circuits - preset a channel number (coarse frequency) by remote, then let the AFC circuit handle the fine tuning :)
« Last Edit: 06/05/2017 03:04 pm by xyzzy »

Offline VAXHeadroom

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...

These are all very good points. Thank you. The way I see it, this can go several ways. The most obvious route is to 3D print the parts and simply cover them with EMI shielding copper conductive adhesive tape. Alternatively, one could 3D print, sand, and then copper plate. Yet another option is to 3D print and then use a process like the Virtual Foundry (http://www.thevirtualfoundry.com/) to make solid copper parts. The last option, and the best route in my opinion, is to 3D print wax copies of the end plates and then use the lost wax process to create parts which are then machined to exact specifications.
I'm about to have access to a 3D printer that has a 12" (40cm) square build area and can print higher temp materials like PETG and Nylon.  Also for copper plating I've used a company in Baltimore, MD called Repliform (http://www.repliforminc.com/) who did an amazing job for us on a spherical object.
Usually what you do with these kinds of requirements is 3D print a 'near net shape' (adding extra material) and then machine it down - 'file to fit' :)  As this is circular, you should be able to put it on a lathe and get a really good finish.  Polishing most plastics can be done with a heat gun :D
Oh, and check out this video which was uploaded this morning on 3D printing! (lightly related)
« Last Edit: 06/05/2017 04:17 pm by VAXHeadroom »
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Offline PotomacNeuron

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I do not know whether it is only my opinion or it represents opinion from several others too, but may I suggest we leave alone the 3D printing idea before Shawyer's, EW's, and TheTraveller's claims are confirmed/replicated? After all, they did not use 3D printing. If we pursue this 3D printing idea, I suspect new ideas such as graphene plating, YBCO plating/annealing, explosive forming, powder metallurgy,aspherical shaping, you-name-a-new-tech, will all jump in to delay the tests.

For monomorphic's test, I am especially interested in the direction-relative-to-Earth-magnetic-field null test. It's a pity monomorphic did not carry out this albeit easy test. No, not all known interferences were eliminated in those reported tests. Here is one.
« Last Edit: 06/05/2017 06:31 pm by PotomacNeuron »
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Offline Flyby

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These are all very good points. Thank you. The way I see it, this can go several ways. The most obvious route is to 3D print the parts and simply cover them with EMI shielding copper conductive adhesive tape. Alternatively, one could 3D print, sand, and then copper plate. Yet another option is to 3D print and then use a process like the Virtual Foundry (http://www.thevirtualfoundry.com/) to make solid copper parts. The last option, and the best route in my opinion, is to 3D print wax copies of the end plates and then use the lost wax process to create parts which are then machined to exact specifications.
I've been eyeing this type of high metal content filament for some time....
but...
- did you notice it has a rather high degree of shrinking, because you melt away the 15% of PLA
- It needs a high temperature oven (ceramic baking type) to fuse the copper/bronze/... particles together

The lost wax process is indeed a good option, although it also has some dimensional shrinking issues.
And it will need additional machining to get a smooth interior surface

I'd say, for a quick testing, a 3dprint might be an option, on condition the temperature doesn't go too high...

I still think a mold, lathe copper spinning technique would yield the cheapest, best finished product.
Perhaps it would be a good idea to build the lathe molding shape with 3Dprinting?

Offline Monomorphic

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For monomorphic's test, I am especially interested in the direction-relative-to-Earth-magnetic-field null test. It's a pity monomorphic did not carry out this albeit easy test.

It's on my list. I had to reinforce the workbench legs as they were not designed to be pushed around on wheels. The whole test stand nearly toppled over one day spilling the entire antifreeze dampening fluid reservoir all over the floor and breaking the glass container into a hundred shards.  It took a couple of hours to get that cleaned up and ever since then i've been a little afraid to move it.

Offline Monomorphic

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I'm about to have access to a 3D printer that has a 12" (40cm) square build area and can print higher temp materials like PETG and Nylon. 

The big end, with 3.5cm flanges, is 14.5" (36.5cm) in diameter.  12" is 30cm not 40cm, so I don't think it could be printed even with that printer.

Offline Mark7777777

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Harbin Institute of Technology has applied for two emdrive patents.

I did try to convert the PDFs to English by uploading them to google translate. It didn't do it. If anyone else has other means of doing it ...

Managed to find machine translations for both patents:

CN 105790717 A A microwave-based adaptive tuning system for a non-working microwave thruster and a microwave source adaptive tuning method using the system

http://www.google.com/patents/CN105790717A


CN105775171A Propelling system assisting in reducing weight of propelling system and changing degree and direction of thrust

http://www.google.com/patents/CN105775171A

[Edit: added second patent link]

Would people not think it's a lot of effort to go through and author and file those patents if Harbin Institute of Technology hadn't seen real-life evidence of thrust themselves? Maybe in their own labs?

https://en.m.wikipedia.org/wiki/Harbin_Institute_of_Technology

"HIT is consistently ranked as one of the top universities in the country [3] with a focus on science and engineering.[4][5][6] HIT was ranked 7th in the Best Global Universities for Engineering by U.S. News in 2016.[7] HIT is one of only a handful of universities in the world that have designed, built, and launched their own satellites (in 2004, 2008 and 2013)."
« Last Edit: 06/05/2017 09:13 pm by Mark7777777 »

Offline tchernik

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Would people not think it's a lot of effort to go through and author and file those patents if Harbin Institute of Technology hadn't seen real-life evidence of thrust themselves? Maybe in their own labs?

https://en.m.wikipedia.org/wiki/Harbin_Institute_of_Technology

"HIT is consistently ranked as one of the top universities in the country [3] with a focus on science and engineering.[4][5][6] HIT was ranked 7th in the Best Global Universities for Engineering by U.S. News in 2016.[7] HIT is one of only a handful of universities in the world that have designed, built, and launched their own satellites (in 2004, 2008 and 2013)."

Roger Shawyer has patents yet here we are, discussing the validity of his presumed invention.

Patents by themselves aren't evidence of anything. Given the lack of rigor on their review, nowadays they are just like placeholders for potential intellectual property.

Peer-reviewed papers, communiqués and press releases are a bit more interesting, because they can describe events and happenings that we aren't aware of yet.
« Last Edit: 06/05/2017 09:26 pm by tchernik »

Offline WhirlingWorlds

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I'm about to have access to a 3D printer that has a 12" (40cm) square build area and can print higher temp materials like PETG and Nylon. 

The big end, with 3.5cm flanges, is 14.5" (36.5cm) in diameter.  12" is 30cm not 40cm, so I don't think it could be printed even with that printer.

instead of the 3d printer or lathe, i would suggest you use amateur telescope making (atm) techniques to grind a concavity (or convexity, the tool will do that anyway) in a copper blank.  it requires little prep and just a little research, is far, far cheaper, and would make a much more accurate surface.  there should be many, many videos on youtube on the procedure.  perhaps reach out to the atm community and enlist the aid of an interested volunteer?

Offline dustinthewind

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Hi

I seem to remember that preprint too...

The quantum vacuum as the origin of the speed of light

Quote
We show that the vacuum permeability and permittivity may originate from the magnetization and the polarization of continuously appearing and disappearing fermion pairs. We then show that if we simply model the propagation of the photon in vacuum as a series of transient captures within these ephemeral pairs, we can derive a finite photon velocity. Requiring that this velocity is equal to the speed of light constrains our model of vacuum. Within this approach, the propagation of a photon is a statistical process at scales much larger than the Planck scale. Therefore we expect its time of flight to fluctuate. We propose an experimental test of this prediction.

Thanks for the lead. Will have a read too.

Hi Guys

Normally I lurk and enjoy the show, but I spotted this pertinent preprint on the arXiv today:

Theoretical calculation of the fine-structure constant and the permittivity of the vacuum

An intriguing suggestion at the end is that considering the vacuum in this manner allows for a variable speed of light in the very early universe. But the fact that the Fine Structure Constant can be computed from assuming the vacuum is filled with virtual positronium (some ~10^39 per cubic metre) does lend some credence to Harold White's suggestions about how EM-Drives and kin *might* work.

I haven't sat down and compared them yet, but this sounds very similar to Marcel Urban, et. al.'s paper:

The quantum vacuum as the origin of the speed of light - 2013
https://link.springer.com/article/10.1140%2Fepjd%2Fe2013-30578-7

If anyone has the time to compare them, please keep me in the loop.

Thanks!

I wrote to the authors regarding their work vs the work of Dr Fern and Prof. Woodward, recently published in JBIS. Because their claim that there are 1.11 x 1039 parapositronium "on mass shell" atoms per cubic meter, results in a cubic meter of empty spacing having an instantaneous rest mass of over 2 million metric tons.

I'm looking forward to a response.

https://physics.stackexchange.com/questions/236/how-does-positronium-exist
It appears while positronium can exist, it has a half-life from .125ns to 142ns if the last poster is correct.  What is interesting is depending on the local available energy these positronium can pop in and out of existence.  To me that suggest something similar to phantom particles with zero rest mass but some transient mass depending on the local available energy. 

I am toying with their idea that there is a density of these positronium particles in the vacuum inside the frustum.  At the narrow end having the same density there are less particles than at the large end.  Combine that with increased energy density at the narrow end.  Take the photon density at the narrow end over the positronium density.  If the ratio exceeds one, nature may be some how combining energy from multiple positronium into fewer. (squeezed light?)  More enegy/(virtual particle - almost positronium) should increase the mass.  That is supposing the photons are the disturbed phantom positronium. 

Increased mass at the narrow end would transfer more energy per collision than to the larger end with lighter virtural particles?...  Its almost the opposite direction than the other idea I was toying with. 
« Last Edit: 06/06/2017 12:28 am by dustinthewind »
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Offline oyzw

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Harbin Institute of Technology has applied for two emdrive patents.

I did try to convert the PDFs to English by uploading them to google translate. It didn't do it. If anyone else has other means of doing it ...

Managed to find machine translations for both patents:

CN 105790717 A A microwave-based adaptive tuning system for a non-working microwave thruster and a microwave source adaptive tuning method using the system

http://www.google.com/patents/CN105790717A


CN105775171A Propelling system assisting in reducing weight of propelling system and changing degree and direction of thrust

http://www.google.com/patents/CN105775171A

[Edit: added second patent link]

Would people not think it's a lot of effort to go through and author and file those patents if Harbin Institute of Technology hadn't seen real-life evidence of thrust themselves? Maybe in their own labs?

https://en.m.wikipedia.org/wiki/Harbin_Institute_of_Technology

"HIT is consistently ranked as one of the top universities in the country [3] with a focus on science and engineering.[4][5][6] HIT was ranked 7th in the Best Global Universities for Engineering by U.S. News in 2016.[7] HIT is one of only a handful of universities in the world that have designed, built, and launched their own satellites (in 2004, 2008 and 2013)."
In 2014, Professor Yang Juan conducted emdrive experiments at the Harbin Institute of Technology Laboratory.

Offline Stormbringer

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https://physics.stackexchange.com/questions/236/how-does-positronium-exist
It appears while positronium can exist, it has a half-life from .125ns to 142ns if the last poster is correct.  What is interesting is depending on the local available energy these positronium can pop in and out of existence.  To me that suggest something similar to phantom particles with zero rest mass but some transient mass depending on the local available energy. 



In addition; atoms can be made of muons (Muonium) and Kaons (Kaonium) with similar miniscule half lives. One might speculate that just like conditions or proximity of other particles alters the half life of neutrons there might be conditions that stabilize these fleeting atoms in a like manner.
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Offline Tcarey

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I'm about to have access to a 3D printer that has a 12" (40cm) square build area and can print higher temp materials like PETG and Nylon. 

The big end, with 3.5cm flanges, is 14.5" (36.5cm) in diameter.  12" is 30cm not 40cm, so I don't think it could be printed even with that printer.

Mono...  What is the depth of the curve you are interested in for your large end plate?  What is its shape?

Thanks for all you are doing.....

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