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#240
by
TheTraveller
on 02 Sep, 2016 22:02
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so... where does that leave us, with 1.2mN/kW, instead of 400mN/kW ?
Is it still meaningful for interplanetary missions?
There is still a substantial gap (± x300 times)between what the guys at eagleworks got and what Shawyer claims. If the10 year old NDA has expired on the demonstration device, maybe it would be a good idea for R. Shawyer to contact them and send over that "obsolete" model.
But that's wishful thinking of me , ofc...
I have done 8mN @ 95Wrf or 84mN/kWrf. In build design will do 0.4N/kWrf. Others I know of are around 0.4N/kWrf for 2nd or 3rd build units.
As Roger has said, this isn't magic. There are design guidelines to build 0.4N/kW units. That said building a high Q commercial quality total system (frustum, Rf amp & control system) is not easy, quick nor low cost.
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#241
by
Star One
on 02 Sep, 2016 22:55
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You will all be happy to know, not, that you can expect another storm of ill informed commentary on this paper if the comments I am already seeing are at all illustrative.
I hope this isn't considered to OT but just wanted to give everyone fair warning for the next two or three months.
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#242
by
krio
on 02 Sep, 2016 23:15
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A brainstorm type question: if the cost of building superconducting experiment for Q factor influence verification scales with dimensions of the setup, what's stopping from building a 2x2cm setup with commercially available superconductors at ebay/amazon, drilling the cavity and applying some duct tape?
Not a bad idea, really. Would possibly bring the superconductive type build within the realm of possibility for a DIYer. The challenge would be producing the EM content with the correctly sized wavelength, resonance, etc., which is above my pay grade.
Well, any takers, any objections? Aside from the measuring instruments which I lack this type of test seems to be in the cost range of 100 - 400$, liquid nitrogen and small superconductors are actually dirt cheap and DIYers fool around with those on youtube. And as far as I can tell there is no solid theory to calculate the efficient wavelength by the cavity dimensions so a test using a microwave oven magnetron on a cavity that small would be useful regardless of outcome. Or am I wrong?
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#243
by
TheTraveller
on 02 Sep, 2016 23:17
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In case anybody is interested here is the maggie Roger used in the Demonstrator EmDrive: GA4305
http://www.2450mhz.com/PDF/Manuals/930028%24.pdfAnd guess what? He also had maggie temp driven freq drift issues causing thrust variance as the freq passed through frustum resonance.
I REALLY suggest to read this detailed engineering report several times. I read it 4 times and leaned something new on each read.
Any engineer who reads this report will have no doubt the device works as claimed.
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#244
by
Star One
on 02 Sep, 2016 23:23
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How much does a superconducting drive magnify its effect?
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#245
by
spupeng7
on 02 Sep, 2016 23:26
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Roger's quote is priceless:
http://www.ibtimes.co.uk/emdrive-nasa-eagleworks-paper-has-finally-passed-peer-review-says-scientist-know-1578716
"People all around the world have been measuring thrust.
You've got guys building them in their garages and very large organisations building cavities too.
They're all generating thrust, there's no great mystery.
People think it's black magic or something, but it's not.
Any physicist worth his salt should understand how it works, or if they don't, they should change their profession."
hmmmm...
very unfortunate quote, if you ask me, as such -dare I say - rather populist remark has a very high boomerang tendency...
I understand it comes from years of buildup frustration, of tedious swimming against the main current of scientific consensus, but such a reaction doesn't help as far as credibility goes.
If the EM effect is indeed acknowledged, through experiments/peer review, then R.Shawyer deserves all the credit he can muster, but the backstabbing is - although understandable - really unnecessary...
Insight is a precious gift, comprehension above the norm is a grave responsibility and well... if you solve the big one then, you get to choose how you use the megaphone that comes with it.
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#246
by
TheTraveller
on 02 Sep, 2016 23:31
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You will all be happy to know, not, that you can expect another storm of ill informed commentary on this paper if the comments I am already seeing are at all illustrative.
You do understand the EmDrive may replace all forms of propulsion?
No more 3, 2, 1, ignition.
No more launch pad explosions to report on.
No more noise.
No more fire.
No more wondering if it will explode.
No more firey reentries.
No more astronaut space training.
Your old grandmother & her cat can go into space.
Just a silent and gentle lift to space & back down.
Mars in 3-4 days? Sure as long as you can tolerate 1g thrust gravity all the way there or back.
It all changes.
Lots of companies will lose a lot of money.
Others will make a lot of money.
Told you 2016 is the year the EmDrive comes out of the dark.
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#247
by
TheTraveller
on 02 Sep, 2016 23:38
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How much does a superconducting drive magnify its effect?
Thrust Newtons = (2 Power Q DesignFactor) / c.
Copper frustum has Q 50,000.
Superconducting frustum has Q 1,000,000,000 or 20,000 times greater.
Q 50k = 0.4N/kWrf ~40g/kWrf thrust
Q 1b = 8,000N/kWrf ~0.8mt/kWrf thrust
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#248
by
spupeng7
on 02 Sep, 2016 23:40
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Is it fate or providence that a planet is discovered so relatively close at hand at the same time.
Coincidence.
Serendipity
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#249
by
DIYFAN
on 02 Sep, 2016 23:45
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#250
by
Bob Woods
on 02 Sep, 2016 23:55
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So let's keep it civil here.
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#251
by
ehawk777
on 03 Sep, 2016 00:28
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#252
by
ThinkerX
on 03 Sep, 2016 03:29
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botched quotes
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#253
by
ThinkerX
on 03 Sep, 2016 03:35
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I have done 8mN @ 95Wrf or 84mN/kWrf. In build design will do 0.4N/kWrf. Others I know of are around 0.4N/kWrf for 2nd or 3rd build units.
As Roger has said, this isn't magic. There are design guidelines to build 0.4N/kW units. That said building a high Q commercial quality total system (frustum, Rf amp & control system) is not easy, quick nor low cost.
Traveler, with all due respect, enough is enough. If your device has produced thrust on that scale - or even if it has not - then post the results here and let the math types have a field day. Citing decade old arguments from Shawyer doesn't cut it, not in the presence of new data. You have nothing to lose. Such interaction would help you spot potential flaws with you design, as well as avenues for improvement.
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#254
by
MikeGroovy
on 03 Sep, 2016 05:03
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Is it just me or is the Nassikas Thruster II project giving thrust because of the second law of thermodynamics.. Warm ambient air near the wide end of the supercooled funnel is chilled, lower pressure from the chilling is making more air follow the path of least resistance. Isn't this why we need testing in a vacuum?
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#255
by
DIYFAN
on 03 Sep, 2016 05:31
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Is it just me or is the Nassikas Thruster II project giving thrust because of the second law of thermodynamics.. Warm ambient air near the wide end of the supercooled funnel is chilled, lower pressure from the chilling is making more air follow the path of least resistance. Isn't this why we need testing in a vacuum?
I don't know. But they did put the whole device into a foam box, and then strung the whole box up, to rule out that hypothesis, as I remember.
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#256
by
simplex1
on 03 Sep, 2016 05:41
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Engine thrust, T = 10 mN
Power consumption, P = 1 kW
Engine work time, t = 30 days
Satellite mass, m = 100 kg
Speed gain = (T/m) x t = 259.2 m/s
It appears that even with a thrust of 10 mN/kW a 100 kg satellite can increase its speed with 259.2 m/s per month (3.155 km/s per year) which is quite impressive.
Somebody here claims he obtained 85mN/kWrf. I do not know how much thrust he obtained per kW absorbed from the grid but it seems that more than 10mN/kW which means he is already in possession of a practical engine for small spacecrafts.
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#257
by
tleach
on 03 Sep, 2016 05:54
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A brainstorm type question: if the cost of building superconducting experiment for Q factor influence verification scales with dimensions of the setup, what's stopping from building a 2x2cm setup with commercially available superconductors at ebay/amazon, drilling the cavity and applying some duct tape?
Not a bad idea, really. Would possibly bring the superconductive type build within the realm of possibility for a DIYer. The challenge would be producing the EM content with the correctly sized wavelength, resonance, etc., which is above my pay grade.
Well, any takers, any objections? Aside from the measuring instruments which I lack this type of test seems to be in the cost range of 100 - 400$, liquid nitrogen and small superconductors are actually dirt cheap and DIYers fool around with those on youtube. And as far as I can tell there is no solid theory to calculate the efficient wavelength by the cavity dimensions so a test using a microwave oven magnetron on a cavity that small would be useful regardless of outcome. Or am I wrong?
They've actually done quite a bit of that on this thread over the past year or two. The general consensus seems to be that the smaller the drive, the higher the frequency required to achieve resonance, which most theories hold is necessary to achieve thrust. And the small end should always be slightly larger than the cuttoff frequency of the RF frequency being used.
In fact, The Traveler has created a detailed spreadsheet that will allow the user to input values for length, large diameter, small diameter, frequency, Q-factor and then predicts the thrust of the resulting drive. I'm not 100% sure this is his final version, but it's very interesting:
https://drive.google.com/file/d/0B7kgKijo-p0iUnlaXzc0OFVvc00/viewMonomorphic has been creating virtual frustums and modeling TE mode shapes at various frequencies for quite awhile now:
http://forum.nasaspaceflight.com/index.php?topic=39772.msg1511076#msg1511076The Baby EM Drive ran at 24 GHz:
https://hackaday.io/project/5596-em-driveAnyway, my point is that there is information available to help calculate the appropriate frequency needed to achieve resonance within a given frustum.
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#258
by
TheTraveller
on 03 Sep, 2016 06:14
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Monomorphic and myself are in a small group of 5 active EmDrive builders that share data. Recently I shared the dimensions, mode and operating freq of the commercial S band thruster I'm developing.
To Monomohic's great skill he quickly modeled the frustum and confirmed it's mode & resonant freq. Which shows as Roger has said, it is not magic and these devices can be built as long as you follow the engineering pathway Roger has created.
Additionally Monomorphic is close as to how to properly excite such a high Q cavity to get 0.4N/kWrf results. See attached. From those images note how the guide wavelength gets longer as the diameter drops. Just as Roger shows in his theory talk, which is now on
www.emdrive.com No magic, just applied microwave enginerring that has existed for 65 years.
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#259
by
TheTraveller
on 03 Sep, 2016 06:26
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I have done 8mN @ 95Wrf or 84mN/kWrf. In build design will do 0.4N/kWrf. Others I know of are around 0.4N/kWrf for 2nd or 3rd build units.
As Roger has said, this isn't magic. There are design guidelines to build 0.4N/kW units. That said building a high Q commercial quality total system (frustum, Rf amp & control system) is not easy, quick nor low cost.
Traveler, with all due respect, enough is enough. If your device has produced thrust on that scale - or even if it has not - then post the results here and let the math types have a field day. Citing decade old arguments from Shawyer doesn't cut it, not in the presence of new data. You have nothing to lose. Such interaction would help you spot potential flaws with you design, as well as avenues for improvement.
The only people I'm interested to show operational results to are customers.
Those seeking knowledge should read Roger's detailed engineering build reports. BTW nice photos of the Demonstrator in early build & static tests.
I'm not the only EmDrive builder that will shortly release battery powered, wireless, EmDrive rotary test results & videos.
