Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1802952 times)

Offline TheTraveller

To help in this question it deserves a look the Gerald Kaiser work "Electromagnetic inertia, reactive energy and energy flow velocity" http://iopscience.iop.org/1751-8121/44/34/345206/ and subsequent works by others easy to track in Thomson Reuters WoS.
...
Maybe a good starting point to face EM Drive challenge is to characterize a cavity by irradiating it with wavelets instead of sinusoidal waves...

But there is no way to transmit wavelets, unless using a extremely wideband linear amplifier and antenna (fractal antenna?).

Very interesting papers by Kaiser. Very timely post. Thanks!

Open access download here:
http://arxiv.org/pdf/1105.4834.pdf
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline deltaMass

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Random thought alert - I respect dead scientists, its just that I expect live ones to take it to the next level ;)
Me too! I pay my taxes dammit!
« Last Edit: 07/31/2015 04:22 AM by deltaMass »

Offline deltaMass

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Aircraft engines are very noisy. Even if you cannot see a reconnaissance drone you just have to hear it to shoot it down. If the EMDrive is quiet it would be permit a major increase in audio stealth.
Yabut the massive helium balloons are a dead giveaway  8)

Offline TheTraveller

Aircraft engines are very noisy. Even if you cannot see a reconnaissance drone you just have to hear it to shoot it down. If the EMDrive is quiet it would be permit a major increase in audio stealth.
Yabut the massive helium balloons are a dead giveaway  8)

For sure to be sure ;)
« Last Edit: 07/31/2015 04:49 AM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline A_M_Swallow

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Aircraft engines are very noisy. Even if you cannot see a reconnaissance drone you just have to hear it to shoot it down. If the EMDrive is quiet it would be permit a major increase in audio stealth.
Yabut the massive helium balloons are a dead giveaway  8)

Hopefully an EMDrive receiving power via fuel cells is smaller than the helium balloons.

Offline SteveD

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Just thought I'd note that large magnetrons (10kw/ 9.4 Ghz) for Marine radars are available on Alibaba.  ( (http://www.alibaba.com/product-detail/MSF1425B-MSF-1425B-MSF1425-B-NEW_111310069.html?spm=a2700.7724857.35.1.tYB13c and http://www.njr.com/products/micro/pdf/MSF1425B.pdf).  Not sure of their applicability.  Seemed like a rare part that some folks around here might be interested in.
« Last Edit: 07/31/2015 06:22 AM by SteveD »

Online Rodal

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Interesting calcs digging through the data of Prof Yang.....The cavity they used had a measured Q of 1,531 because it needed a wide bandwidth to try to swallow all their magnetrons output. Adjusting the 4N/kW value to a cavity with a Q of 117,500 (their latest design) the Specific Force would grow to 307N/kW. Playing with the cavity Df to get it to 0.95 and still having the 117.500 unloaded Q would maybe boost it another 50%....
What is your best estimate of the dimensions of the resonant truncated cone cavity Prof. Yang used to obtain her largest reported thrust and thrust/InputPower ?

Big Base Diameter =   

Small Base Diameter =

Length (measured perpendicular to the bases) =
« Last Edit: 07/31/2015 06:42 AM by Rodal »

Offline TheTraveller

Interesting calcs digging through the data of Prof Yang.....The cavity they used had a measured Q of 1,531 because it needed a wide bandwidth to try to swallow all their magnetrons output. Adjusting the 4N/kW value to a cavity with a Q of 117,500 (their latest design) the Specific Force would grow to 307N/kW. Playing with the cavity Df to get it to 0.95 and still having the 117.500 unloaded Q would maybe boost it another 50%....
What is your best estimate of the dimensions of the resonant truncated cone cavity Prof. Yang used to obtain her largest reported thrust and thrust/InputPower ?

Big Base Diameter =   

Small Base Diameter =

Length (measured perpendicular to the bases) =

Never tried to work out the dimensions. Prof Yang is like Shawyer and doesn't give away the frustum dimensions. Shawyer does gives more dimensions, Q and Df details than Prof Yang but still not enough to pin down his 3 frustum internal dimensions.

Are there any photos of Prof Yang's frustums? Did once read there was a photo posted to NSF but could never find it. Would be good to pin down the circa 2010 frustum dimensions.

Will see what I can come up with.
« Last Edit: 07/31/2015 06:54 AM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline deltaMass

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@TheTraveller:
Do you have an estimate of the thrust and power you plan to use?
Oh, the power is 100W I think from that amp you showed.
« Last Edit: 07/31/2015 06:55 AM by deltaMass »

Offline OttO

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For DIY would it be practical to do a form in machinable Wax:

http://www.machinablewax.com/technical.php

and plate it with copper (chemical).
After that either you melt the wax or keep it (If I remember the refraction index of wax for microwaves is quite interesting.)




Offline TheTraveller

@TheTraveller:
Do you have an estimate of the thrust and power you plan to use?
Oh, the power is 100W I think from that amp you showed.

Based on the Shawyer Force equation, with a Df of 0.925, a Q of 50k, TE013 and 100W, Force goal is 30mNs. If I can tweak the cavity to 100k, using constant diameter cylindrical short sections and flat end plates, would expect 60mNs.

But with the Prof Yang details I dug out, it may be a lot higher with my 2nd dual tunable flat end plate build as attached.

Have done a few drawing changes on the prototype frustum to allow the short cylindrical sections to be added or removed as desire. Also plan to experiment with a non extended cavity and flat versus spherical end plates to measure Q change and Force generated to see if Force does scale with Q.

I plan to try to answer a lot of questions.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline OttO

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Em drive  = transient damping effects  + Q and Patm dependant            + Delta Tfrustum dependant
               = various fields coupling         + near field momentum transfer + IR photon rocket


  :)



« Last Edit: 07/31/2015 08:28 AM by OttO »

Offline OttO

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Quantum spin Hall effect of light
http://arxiv.org/abs/1502.03319

"The corresponding spin-momentum locking originates solely from the basic properties of evanescent waves in Maxwell equations, and can be observed at any interface with the vacuum supporting surface or guided waves.
 In particular,surface plasmon-polaritons at a metal-vacuum interface exhibit features similar.......
This offers robust angular-momentum-to-direction coupling in various surface waves as well as
important analogies and generalizations involving quantum and classical wave theories."

Offline TheTraveller

For some time I had been concerned about the placement of the TE mode excitation antenna inside the tapered waveguide with it's spherical wave fronts that may be very difficult to couple the antenna to without introducing significant phase distortion in the spherical standing waves.

With my latest frustum design I believe I have found a way to both use a flat end plate for the big end and do a conventional excitation antenna design and placement.

The idea is to add a 1/2 lambda g (constant diameter waveguide guide wavelength) length cylindrical copper section that matches the diameter of the big end. The antenna is then positioned 1/4 lambda g away from the big end flat plate with the dipole antenna being 1/4 lambda 0 (external freq wavelength) long. This is very conventional microwave stuff.

This constant diameter cylindrical section should also convert the spherical wavefronts inside the tapered waveguide into planar wave fronts in the constant diameter section and allow high Q, low phase distortion bounces off the big end flat plate. The small end may be spherical or it may use the latest Prof Yang small cylindrical setback with a flat plate.

BTW the EM wave bouncing off this big end flat plate will be travelling at the group velocity of the constant diameter cylindrical waveguide as determined by it's cutoff planar wavelength. No doubt about it.

Idea attached. Comments most welcome.
« Last Edit: 07/31/2015 09:15 AM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline martinc

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slightly off topic? but very curious...

'Ohtsuki and Ofuruton[46][47] described producing “plasma fireballs” by microwave interference within an air-filled cylindrical cavity fed by a rectangular waveguide using a 2.45 GHz, 5 kW (maximum power) microwave oscillator'

'Many modern experiments involve using a microwave oven to produce small rising glowing balls, often referred to as plasma balls. Experiments by Eli Jerby and Vladimir Dikhtyar in Israel revealed that microwave plasma balls are made up of nanoparticles with an average radius of 25 nm. The Israeli team demonstrated the phenomenon with copper, salts, water and carbon'

these all rely on some source material.. although copper is off course the fustrum material?!

ps... if you're not too upset or offended by the 'hitler/downfall' meme i found this hilarious. just when you think that meme has gotten old..

http://captiongenerator.com/48295/Hitler-Reacts-to-current-EmDrive-Situation

Online Flyby

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Never tried to work out the dimensions. Prof Yang is like Shawyer and doesn't give away the frustum dimensions. Shawyer does gives more dimensions, Q and Df details than Prof Yang but still not enough to pin down his 3 frustum internal dimensions.

As I've started on building a guesstimate top-view of the complete Yang setup(cavity+waveguide), with the little info i could gather, i can confirm the lack of consistency in her drawings.

Although they appear to look as accurate engineering drawings, the different drawings do not match very well as far as their dimensions go.
That lack of consistency of the different drawings let me conclude that they are not accurate engineering drawings, but more schematic/principle drawings dressed up as accurate drawings.

No surprise actually, if you want to keep some secrets close to the chest...

So yes, it is highly unlikely we're looking at the accurate dimensions of dr. Yang's device...

Offline TheTraveller


Never tried to work out the dimensions. Prof Yang is like Shawyer and doesn't give away the frustum dimensions. Shawyer does gives more dimensions, Q and Df details than Prof Yang but still not enough to pin down his 3 frustum internal dimensions.

As I've started on building a guesstimate top-view of the complete Yang setup(cavity+waveguide), with the little info i could gather, i can confirm the lack of consistency in her drawings.

Although they appear to look as accurate engineering drawings, the different drawings do not match very well as far as their dimensions go.
That lack of consistency of the different drawings let me conclude that they are not accurate engineering drawings, but more schematic/principle drawings dressed up as accurate drawings.

No surprise actually, if you want to keep some secrets close to the chest...

So yes, it is highly unlikely we're looking at the accurate dimensions of dr. Yang's device...

We share the same opinion.

There is a LOT of EMDrive "Secret Squirrel Secret Sauce" IP that is never disclosed or misquoted to confuse. Here I offer as example the incorrect Tajmar cavity dimensions. I suggest the recent Tajmar and other experimenters misinformation doesn't stop there.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline TheTraveller

As of July 2014 the Tesla battery is rated at 245Wh/kg.

200kWh would then mass out at 816kg. Add 100kg for EMDrives and 200kg for a simple frame. Total cargo less mass 1.1t. At 300N/kw = 36kWr of Rf and at 85% e to Rf = 43kWe of electrical power. Approx 4.6hr float time.

Assuming 300N/kW is doable non cryo, an EMDrive and Lithium powered skeleton frame floater drone is possible.
« Last Edit: 07/31/2015 11:55 AM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline rfmwguy

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Simple einstein questions. electromagnetic photons traveling at the speed of light, have therefore gained mass...
1) where are they borrowing mass from?
2) can they exist in a sublight or superluminal state?
3) is dark matter sublight photons waiting to be excited to c?
 
Rusty physics minds want to know ;)

Offline Star One

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You were quite happy to lecture a poster on here about doing further research. So I'll turn that around and suggest if you want to know the people with alternatives to dark matter theory that you do some research on the matter.

It's not my job to justify your statements for you.

If you feel their is some exodus of scientists away from dark matter or dark energy, prove it.  I'm not going on some wild goose chase to learn about some fact I couldn't care less about.  As a "fringe" man yourself (and I don't mean that in a disparaging way, just that you are interested in alternative theories), you know how many people believe a theory has no impact on whether or not it's true.  I know this likewise, and so
Quote
There are an increasing number of scientists who are having doubts about the whole concept of Dark Matter/Energy.
is irrelevant. 

But I figured I'd ask to see if you could rustle up the source you got that from, or if you just made it up on the spot.

Such sources are easy to find should you have the mind to look.

Study finds possible alternative explanation for dark energy

Here's the article.

http://m.phys.org/news/2014-12-alternative-explanation-dark-energy.html

Here's the paper.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0115550

Here's one relating to Dark Matter.

It’s crunch time for dark matter if WIMPs don’t show

https://www.newscientist.com/article/mg22229712.600-its-crunch-time-for-dark-matter-if-wimps-dont-show
« Last Edit: 07/31/2015 12:26 PM by Star One »

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