Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1800426 times)

Offline X_RaY

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Note to experimentalists:

For safety, run an EM detector around the outside of your emdrive while its powered up.  Either through shoddy construction(likely) or some as yet unknown (to me) phenomenon, my resonator is leaking radiation from the small end.  Based on the fall-off as a function of distance I believe it is evanescent.  I have spectrum analyzer on order; when it arrives I'll have a better idea of what it is.

<lurk />
You can use copper adhesive tape to easy fix any leakage :)
http://www.iccfl.com/index.php?cPath=135_184&osCsid=ur8g03ipgtkkdh6src34otdh84
This is great stuff. Got my copper tape with conductive adhesive froM Mcmaster carr. Their warehouse is 15 minutes from my house...cool.
Yes it works fine :)

Did you use the thermal sensor of the W oven it selves (thermal overheat protection)?
In your first video* it was already inside the chassis and not fixed to the magnetron. Would be interesting to see when that thing is shutting down the power or the temperature is ok...

* frustum with magnetron, not the general setup for the force measurement
« Last Edit: 08/04/2015 06:41 PM by X_RaY »

Offline rfmwguy

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Thermal tests done including 5 minute run at 30% power, which is what I'll use for fulcrum test. What I learned: Matching into frustum is good, magnetron ran at temperatures well below 200C. Still had minor arcing, corrected it with full teardown and replacement of Db with mesh only, no copper clad. IOW, frustum is now all mesh except for Ds where magnetron is mounted. There was no arcing on Ds throughout any thermal testing. Plasma focused on Db, interestingly enough diagonally across from radome, not directly across axially.

Here's the video, time to do yard work, oh joy:

Great test! I noticed as your cavity heated up the arcing diminished. Do you think it was due to the magnetron stabilizing? Your cavity pretty much negates thermal expansion with the screen (nice idea).

I just want to hear you sing "Never, Never Gonna Give Ya Up"  by Barry White. Nice voice for narrating.

Shell
Thanks shell...coworkers used to tell me I should be on radio in PM with a talk show called Dr Love...snicker.

I am glad I used mesh, another hi power test I didn't record had no arcing on Db mesh-only surface. Also, the wood underneath it was cool to touch, meaning the mesh stopped most of the energy.

The arcing was nowhere near contact points, it was on copper clad in 2 or 3 spots abt 3 cm from edge...in the open. Have to think about it some more. No real reason for it except the copper might have been thin or oxidized, basically a high resistance point...not sure yet. Regardless, it was wasting energy.

I'm starting to agree with doc, its not a closed system. Whatever is happening, if anything, involves the environment outside the frustum. I'm not sure a hermetically sealed frustum is any big advantage...might be a disadvantage.

Offline X_RaY

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Offline rfmwguy

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Note to experimentalists:

For safety, run an EM detector around the outside of your emdrive while its powered up.  Either through shoddy construction(likely) or some as yet unknown (to me) phenomenon, my resonator is leaking radiation from the small end.  Based on the fall-off as a function of distance I believe it is evanescent.  I have spectrum analyzer on order; when it arrives I'll have a better idea of what it is.

<lurk />

Good advise.

Please share your dimensions, frequency and excitation mode as then I'll run a set of number for you.

How do you know you have resonance?

Are you using a magnetron or narrow band Rf amp?

What wattage?

Thanks for your reply and good luck.
I dunno mr t, haven't seen any pics or videos, so elizabeth might be working on a virtual frustum ;)

Offline rfmwguy

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Note to experimentalists:

For safety, run an EM detector around the outside of your emdrive while its powered up.  Either through shoddy construction(likely) or some as yet unknown (to me) phenomenon, my resonator is leaking radiation from the small end.  Based on the fall-off as a function of distance I believe it is evanescent.  I have spectrum analyzer on order; when it arrives I'll have a better idea of what it is.

<lurk />
You can use copper adhesive tape to easy fix any leakage :)
http://www.iccfl.com/index.php?cPath=135_184&osCsid=ur8g03ipgtkkdh6src34otdh84
This is great stuff. Got my copper tape with conductive adhesive froM Mcmaster carr. Their warehouse is 15 minutes from my house...cool.
Yes it works fine :)

Did you use the thermal sensor of the W oven it selves (thermal overheat protection)?
In your first video* it was already inside the chassis and not fixed to the magnetron. Would be interesting to see when that thing is shutting down the power or the temperature is ok...

* frustum with magnetron, not the general setup for the force measurement
The thermal switch is 160C and would have been close to tripping on my setup. Yes, the mag power injection is closer to nasa than spr and julian. Ew had a loop antenna in almost the same locale.

Offline zen-in

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...
 

100MHz is a nice frequency range to deal with but it is bang in the middle of the UK's civilian FM radio range (87.5 - 108MHz). Anyone using a leaky Faraday cage with a kW magnetron in that frequency range will probably receive legally enforceable complaints about interference.

Does around 100MHz mean the resonate frequency of the frustum in the EM Drive can be designed to be say 110MHz or 120MHz or 200MHz or 75MHz?

It is currently early August 2015, so the FCC, Ofcom (UK) and overseas regulators can still give 'suggestions' for a suitable frequency range before new thrust frustums are made. They will have to allow for air at 1 atmosphere, low pressure nitrogen and the vacuum of space when choosing a range.

Anyone can ask a regulator for advice but to be taken seriously a formal request to reserve a frequency range for spacecraft thrusters probably has to come from an authority such as NASA. If the government delays too long all the EM Drives will say "Made in China" and use a frequency chosen by the Chinese Government.

All EM-Drive experiments that use more than 20 Watts CW and that are not done inside a shielded room violate FCC laws in the US.   It doesn't matter what the frequency is; although some frequencies may be under the management of the NTIA instead of the FCC.   All it takes is for someone to detect the high power interference from an EM-Drive experiment, locate the source by triangulation, and then report their observations to the FCC.  Enforcement can result in hefty fines.   Other countries have similar spectrum management laws.  Experimenters tend to believe the microwave oven frequencies are free for them to use because all ovens leak some radiation anyway.   The problem is once you remove a magnetron from an oven that is a non-conforming use; something the FCC, if there is an enforcement action, will take a dim view of.  The wide range of emissions interferes with Part 15 devices and scientific work including SETI, radio astronomy, and NASA deep space satellites.

It has become obvious to me the EM-drive is bogus science.   I don't believe anything Mr. Shawyer claims.   The Eagleworks project just got less and less "thrust".   Yang doesn't want to discuss the research she did.   Maybe the Chinese authorities see a benefit in using it for a misinformation campaign, akin to the USAF UFO hoax of the 50's.   So I don't think it is worth polluting RF spectrum anymore with this pointless activity.
« Last Edit: 08/04/2015 07:35 PM by zen-in »

Offline CW

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I try following this forum daily, but frankly: too many posts! :) In case this was not posted yet, the Germans are at it again. This time with 3D printed cavity:

https://hackaday.io/project/5596-em-drive/log/22027-3d-printed-tuneable-cavity

Gesundheit!
Reality is weirder than fiction

Offline flux_capacitor

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When cavities become larger and with a higher cone angle and shorter length, the spherical ends also become non negligible. This is obvious but I showed this graphically in a previous post.

Thorough this topic we always calculate the "cutoff diameter" along the diameter d (in green in the pic below) as for a cylindrical waveguide or frustum cavity with flat ends (@Rodal I know there is no such thing as a "sharp cut-off" in a frustum cavity as shown in the scientific literature you pointed out, yet we need this "cylindrical-equivalent cut-off diameter" to calculate the small end length).

But in the following picture, the wave fronts are spherical and bounce between spherical end plates. Those ends are quite large. Are we sure the "cutoff diameter" should not be calculated as the arc length (in red) instead of the diameter d (in green)?
« Last Edit: 08/04/2015 08:16 PM by flux_capacitor »

Online sghill

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There was talk earlier today about oxidizing effects inside the cavity contributing to thrust readings.  Why not make the frustum out of aluminum or coat a copper frustum with easily obtainable chrome?

Also, Mulletron had this quote from Thread 2 back in May that I think got missed by many of the newcomers, so I thought I'd post it here after reading Zen-in's post a second ago:

"Want to make sure it isn't forgotten that:
Shawyer said to use narrow band source for cavity with shaped ends.
Wideband is for cavity with flat ends.

Thus, Eagleworks is using the wrong type of signal source.
Can't say we didn't tell them."
Bring the thunder Elon!

Offline X_RaY

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...
 

100MHz is a nice frequency range to deal with but it is bang in the middle of the UK's civilian FM radio range (87.5 - 108MHz). Anyone using a leaky Faraday cage with a kW magnetron in that frequency range will probably receive legally enforceable complaints about interference.

Does around 100MHz mean the resonate frequency of the frustum in the EM Drive can be designed to be say 110MHz or 120MHz or 200MHz or 75MHz?

It is currently early August 2015, so the FCC, Ofcom (UK) and overseas regulators can still give 'suggestions' for a suitable frequency range before new thrust frustums are made. They will have to allow for air at 1 atmosphere, low pressure nitrogen and the vacuum of space when choosing a range.

Anyone can ask a regulator for advice but to be taken seriously a formal request to reserve a frequency range for spacecraft thrusters probably has to come from an authority such as NASA. If the government delays too long all the EM Drives will say "Made in China" and use a frequency chosen by the Chinese Government.

All EM-Drive experiments that use more than 20 Watts CW and that are not done inside a shielded room violate FCC laws in the US.   It doesn't matter what the frequency is; although some frequencies may be under the management of the NTIA instead of the FCC.   All it takes is for someone to detect the high power interference from an EM-Drive experiment, locate the source by triangulation, and then report their observations to the FCC.  Enforcement can result in hefty fines.   Other countries have similar spectrum management laws.  Experimenters tend to believe the microwave oven frequencies are free for them to use because all ovens leak some radiation anyway.   The problem is once you remove a magnetron from an oven that is a non-conforming use; something the FCC, if there is an enforcement action, will take a dim view of.  The wide range of emissions interferes with Part 15 devices and scientific work including SETI, radio astronomy, and NASA deep space satellites.

It has become obvious to me the EM-drive is bogus science.   I don't believe anything Mr. Shawyer claims.   The Eagleworks project just got less and less "thrust".   Yang doesn't want to discuss the research she did.   Maybe the Chinese authorities see a benefit in using it for a misinformation campaign, akin to the USAF UFO hoax of the 50's.   So I don't think it is worth polluting RF spectrum anymore with this pointless activity.
In principle you are right with this rules(I know about the maximum permissible value, very low power levels  :-\ ) but for any outstanding with a W-meter it looks like a defect microwave oven and it's difficult to measure from far away ;)  ;D

This thread is much more interesting to locate these people, but who want that?
Its just science and most members here, know what they are doing (hope for). :)

search for "magnetron" on Youtube, there are some people who are crazy, not here..
The more important point is to sensibilize the people to be careful with the W and use a good shielding
« Last Edit: 08/04/2015 08:40 PM by X_RaY »

Offline deltaMass

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FYI

http://arxiv.org/pdf/1507.05828.pdf
http://arXiv.org/pdf/1311.1095.pdf
Very interesting and another reason to get into space - quantum computers (wherever they and their dogs are) work better in space. On the down side, the kind of experiment required would seem beyond the capabilities of the ISS. Singing Bowie tunes isn't going to cut it.
« Last Edit: 08/04/2015 08:48 PM by deltaMass »

Offline deltaMass

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Note to experimentalists:

For safety, run an EM detector around the outside of your emdrive while its powered up.  Either through shoddy construction(likely) or some as yet unknown (to me) phenomenon, my resonator is leaking radiation from the small end.  Based on the fall-off as a function of distance I believe it is evanescent.  I have spectrum analyzer on order; when it arrives I'll have a better idea of what it is.

<lurk />
You can use copper adhesive tape to easy fix any leakage :)
http://www.iccfl.com/index.php?cPath=135_184&osCsid=ur8g03ipgtkkdh6src34otdh84
This is great stuff. Got my copper tape with conductive adhesive froM Mcmaster carr. Their warehouse is 15 minutes from my house...cool.
Ha! Let me guess - it's the reason you bought the house  :D

Online Rodal

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When cavities become larger and with a higher cone angle and shorter length, the spherical ends also become non negligible. This is obvious but I showed this graphically in a previous post.

Thorough this topic we always calculate the "cutoff diameter" along the diameter d (in green in the pic below) as for a cylindrical waveguide or frustum cavity with flat ends (@Rodal I know there is no such thing as a "sharp cut-off" in a frustum cavity as shown in the scientific literature you pointed out, yet we need this "cylindrical-equivalent cut-off diameter" to calculate the small end length).

But in the following picture, the wave fronts are spherical and bounce between spherical end plates. Those ends are quite large. Are we sure the "cutoff diameter" should not be calculated as the arc length (in red) instead of the diameter d (in green)?

By all means it should be calculated by the arc length, for consistency sake.  But there is nothing consistent about modeling a closed cavity as an open waveguide, so this is par for the course of the lack of consistency.  There is nothing consistent in the so called "thrust" measurements either, that differ by several orders of magnitude between different researchers. 

So it is understandable that when reported thrusts differ by orders of magnitude, and when the position alone of the EM Drive produces different results by a large percentage, or that the thrust drops by orders of magnitude in vacuum, that there is inconsistency regarding these "rules".


Offline rfmwguy

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Note to experimentalists:

For safety, run an EM detector around the outside of your emdrive while its powered up.  Either through shoddy construction(likely) or some as yet unknown (to me) phenomenon, my resonator is leaking radiation from the small end.  Based on the fall-off as a function of distance I believe it is evanescent.  I have spectrum analyzer on order; when it arrives I'll have a better idea of what it is.

<lurk />
You can use copper adhesive tape to easy fix any leakage :)
http://www.iccfl.com/index.php?cPath=135_184&osCsid=ur8g03ipgtkkdh6src34otdh84
This is great stuff. Got my copper tape with conductive adhesive froM Mcmaster carr. Their warehouse is 15 minutes from my house...cool.
Ha! Let me guess - it's the reason you bought the house  :D
Just lucky...I had sworn off electronics several years ago, built computers, ham repeaters, direction finding equipment, hifi speakers, amps, etc...kinda missed the smell of a hot soldering iron ;)

Offline CraigPichach

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In the NASA thrust data they seem to take seconds before seeing "thrust" on their Q-Thruster frustrums... any thoughts as to why the delay? Shouldn't this be occurring as soon as resonance is reached in an order of microseconds? Does it take them that long to reach resonance? Any thoughts?

Online SeeShells

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Great test! I noticed as your cavity heated up the arcing diminished. Do you think it was due to the magnetron stabilizing? Your cavity pretty much negates thermal expansion with the screen (nice idea).

I just want to hear you sing "Never, Never Gonna Give Ya Up"  by Barry White. Nice voice for narrating.

Shell
Thanks shell...coworkers used to tell me I should be on radio in PM with a talk show called Dr Love...snicker.

I am glad I used mesh, another hi power test I didn't record had no arcing on Db mesh-only surface. Also, the wood underneath it was cool to touch, meaning the mesh stopped most of the energy.

The arcing was nowhere near contact points, it was on copper clad in 2 or 3 spots abt 3 cm from edge...in the open. Have to think about it some more. No real reason for it except the copper might have been thin or oxidized, basically a high resistance point...not sure yet. Regardless, it was wasting energy.

I'm starting to agree with doc, its not a closed system. Whatever is happening, if anything, involves the environment outside the frustum. I'm not sure a hermetically sealed frustum is any big advantage...might be a disadvantage.
We will hopefully see the difference on the merits of a open or closed system when you get your frustum to the fulcrum for testing thrust. I've been tooting the evanescent horn for months now, maybe we can get some data. Exciting times!

It meant also the Db reflected the wave, maintaining a resonance and a Q, otherwise you heat it up. A good test!!! And my heartfelt congratulations.

Shell

Offline flux_capacitor

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In the NASA thrust data they seem to take seconds before seeing "thrust" on their Q-Thruster frustrums... any thoughts as to why the delay? Shouldn't this be occurring as soon as resonance is reached in an order of microseconds? Does it take them that long to reach resonance? Any thoughts?

To my knowledge (I may be wrong) Eagleworks didn't experience any significant delay after applying power and before measuring thrust. They used a solid-state RF amp that was already tuned for the matching resonant frequency of the cavity. See data available in the original paper, especially:

Figure 22. TE012 test data, quality factor of 22000, applied power of 2.6 watts, net average thrust of 55.4 micronewtons.

attached below. See "RF ON" in red applied for 30 seconds, with a thrust signature appearing when RF was switched on, and disappearing when switched off.

However I wonder what is the ~70N quick peak during a few seconds before the "net thrust" of ~60N.

You may mistake NASA's data with Shawyer's, who reported, using a magnetron:
Quote from: Roger Shawyer
The engine only starts to accelerate when the magnetron frequency locks to the resonant frequency of the thruster, following an initial warm up period.

I suspect the "warm up period" includes the fine tuning of the moveable small end plate through a stepper-motor, seeking for the correct resonant frequency.
« Last Edit: 08/04/2015 10:31 PM by flux_capacitor »

Online SeeShells

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There was talk earlier today about oxidizing effects inside the cavity contributing to thrust readings.  Why not make the frustum out of aluminum or coat a copper frustum with easily obtainable chrome?

Also, Mulletron had this quote from Thread 2 back in May that I think got missed by many of the newcomers, so I thought I'd post it here after reading Zen-in's post a second ago:

"Want to make sure it isn't forgotten that:
Shawyer said to use narrow band source for cavity with shaped ends.
Wideband is for cavity with flat ends.

Thus, Eagleworks is using the wrong type of signal source.
Can't say we didn't tell them."
Or this...
http://www.caswellplating.com/electroplating-anodizing/plug-n-plate-brush-plating-kits.html?p=1

Online SeeShells

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When cavities become larger and with a higher cone angle and shorter length, the spherical ends also become non negligible. This is obvious but I showed this graphically in a previous post.

Thorough this topic we always calculate the "cutoff diameter" along the diameter d (in green in the pic below) as for a cylindrical waveguide or frustum cavity with flat ends (@Rodal I know there is no such thing as a "sharp cut-off" in a frustum cavity as shown in the scientific literature you pointed out, yet we need this "cylindrical-equivalent cut-off diameter" to calculate the small end length).

But in the following picture, the wave fronts are spherical and bounce between spherical end plates. Those ends are quite large. Are we sure the "cutoff diameter" should not be calculated as the arc length (in red) instead of the diameter d (in green)?

By all means it should be calculated by the arc length, for consistency sake.  But there is nothing consistent about modeling a closed cavity as an open waveguide, so this is par for the course of the lack of consistency.  There is nothing consistent in the so called "thrust" measurements either, that differ by several orders of magnitude between different researchers. 

So it is understandable that when reported thrusts differ by orders of magnitude, and when the position alone of the EM Drive produces different results by a large percentage, or that the thrust drops by orders of magnitude in vacuum, that there is inconsistency regarding these "rules".
When I first joined I wondered why the cavity wasn't shaped like this?

Added:
When our distance ancestors started to hit rock on rocks I wonder how many rock they smashed together to finally arrive at the process of chipping flint? Somethings change and somethings don't.
Shell

Added: Would anyone like to comment why this would not work, it still intrigues me. It is drawn within the internal radius of a circle.
« Last Edit: 08/05/2015 12:36 AM by SeeShells »

Online SeeShells

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<lurk />
Ha! Let me guess - it's the reason you bought the house  :D
Just lucky...I had sworn off electronics several years ago, built computers, ham repeaters, direction finding equipment, hifi speakers, amps, etc...kinda missed the smell of a hot soldering iron ;)

Me too. I always had a workshop and in the last few years all those toys have gathered dust. I didn't know until I started this project how much I missed it. I should have never hung up that soldering iron.

Got this beautiful sheet of copper in from 
https://www.onlinemetals.com/merchant.cfm?pid=15244&step=4&showunits=inches&id=966&top_cat=87
 Took me a 1/2 hour to unbox it. ;) @ .032 thick it will make a great frustum.

Shell

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