Author Topic: EM Drive Developments - related to space flight applications - Thread 2  (Read 2100183 times)

Offline deltaMass

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We can figure out the true thrust now (T=thrust, a=air effect, in gm-wt)
T + a = -0.54
-T + a = +0.54/7
solving by eliminating ‘a’ gives
T = -0.31 gm-wt

so thrusting forward at the small end

Quote
the thrust downwards is around 7 times smaller. difference on the scale is only 0.20 grams

I'm confused.
From Iulian's quote, wouldn't Test 1 = 0.2*7=1.4g and Test 2 = 0.2 . Then the equation would be set up like this?
T=thrust
A=air

T+A=1.4g
T-A=0.2g
T=0.8g
A=0.6g
We are both wrong. He said two contradictory things
"I got 1/7th of the previous thrust, in the opposite direction" and
"I got 2 gm-wt thrust downwards"


Originally he got 0.54 gm-wt upwards, so 1/7th would be 0.08 - yet he says 0.2
I'll go with 0.2. T assumed towards small end.

T + A = 0.54 (up)
-T + A = -0.2 (down)

Solving:
T = 0.37 (thrusts from small end)
A = 0.17 (~50% of the thrust)
« Last Edit: 05/21/2015 07:58 PM by deltaMass »

Offline TheTraveller

The cutoff wavelength equation currently used for the Df equation is based on the dominant circular waveguide TE11 mode.

Shawyers frustum patent mentions the mode used is TM01 as per the attached. Means a different cutoff equation is required, which will alter the cutoff, guide and resonance wavelengths.

Will mod my spreadsheet and see how it changes things.

My bed time, so report back in 8 hours or so.
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Online Rodal

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We haven't heard TheTraveller's opinion.

Should we change the Experimental Spreadsheet assuming that Shawyer made a typo and the DesignFactor for the Demonstrator was 0.484 instead of 0.844 ?

Well, I was guessing he'd say yes, so I changed it already on http://emdrive.echothis.com/Experimental_Results.  Will of course switch it back if consensus says otherwise.

Could you also please change the length to  0.187m  ?.:

I also think the cavity length needs to be adjusted on the Demonstrator Thruster to .187m.

My reasoning and measurements:

I believe Shawyer angled the cone to his expectation of where the small diameter plate will be.  When the device is turned on the plate is slightly back inside the cylinder and gradually moved forward until there is phase lock. The length of the cylinder, in part, is to accommodate the movement mechanism and the volume of the small plate.

In my recent model the cone length is exactly .187m (from the face of the small plate to the face of the large plate). Slightly longer than the .183m calculated from 3 * .123m / 2 - based on .2450Ghz. I think 4mm is ample distance to move the small plate to achieve phase lock as I described above.

Did I do the math right?

Offline rfmwguy

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...
(1) Magnetic susceptibilities of paramagnetic and diamagnetic materials... see anything interesting?
http://www.kayelaby.npl.co.uk/general_physics/2_6/2_6_6.html

mass susceptibility per kilogram, χ, at 20°C

Vacuum    .  .  .  .  0
   
Polyethylene   .  .  .+0.2 *10^(-8)  (paramagnetic)
   
Aluminium  .  .  .  . +0.82*10^(-8)  (paramagnetic)

Copper      .  .  .  .  −0.107*10^(-8) (diamagnetic)

All very small values compared to iron, cast iron and other magnetic materials

The value for Polyethylene confirms that the magnetic permeability of HDPE shoud be close to 1.

However, this is for the real part of the susceptibility.  I recall that Paul March said that what was most interesting were the imaginary components of the permittivity and the permeability.

Can anyone find the imaginary permittivity and imaginary permeability for HDPE ?

The imaginary parts act as absorption coefficients (more in the direction of attenuation pointed out by Todd)

The use of HDPE rather than PTFE at MW freqs has been bothering me. Nowhere over 1 GHz have I heard of HDPE, which could indicate high moisture absorption or reflectability. Also, the melting point of HDPE is rather low compared to the 250 deg C of PTFE.

The comparison tables are here: http://www.vanderveerplastics.com/compare-materials.html?sel1=hdpe&sel2=teflon-ptfe-fep

If someone knows why HDPE (typically plastic milk jugs( were initially used, it would be interesting.

"High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a polyethylene thermoplastic made from petroleum. It is sometimes called "alkathene" or "polythene" when used for pipes.[1] With a high strength-to-density ratio, HDPE is used in the production of plastic bottles, corrosion-resistant piping, geomembranes, and plastic lumber. HDPE is commonly recycled, and has the number "2" as its resin identification code (formerly known as recycling symbol)." per http://en.wikipedia.org/wiki/High-density_polyethylene

Online Rodal

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...Chris's article mentioned some very fast transit times, but no mention of what the actual impulse number is.

...Chris's article didn't seem to indicated that the power requirements were unfeasible.   And that the thrust to power input ratio went down as power went up? ...
Welcome to the thread.   Just a short answer and comment regarding the above points.  It was not Chris's article.  I was one of three authors.  The sections you describe paraphrased exactly what Dr. White had written in AIAA papers and what Paul March had written in his papers or at the forum.  There was not enough space to provide a thorough review of the theories in a form that could be understood to a general audience.  I did add to the article a number of objective counterarguments where appropriate as the fact that the EM Drive appears to violate conservation of momentum.  In General Relativity momentum and energy are tied together in the stress-energy tensor, so that if something violates conservation of momentum it is not surprise that it will violate conservation of energy.
I also added that Dr. White's theory assumes a mutable, degradable Quantum Vacuum (in contrast with the prevailing understanding that it is immutable and non-degradable).  I also made a small argument based on the immutability of elementary particles no matter where and when created in the Universe, and also included the objection due to frame-independence.  I was also responsible for the fact that the article never mentions the words "warp-drive", or mentions the word "Alcubierre drive", that nevertheless appeared in other publications.

I hope that others will answer your remaining questions  :)

Take a gander at the section on energy conservation here:

http://emdrive.echothis.com/Generic_EM_Drive_Information
« Last Edit: 05/21/2015 09:02 PM by Rodal »

Offline deltaMass

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The bottom line is that nobody understands how this thing works.

Offline Reactionless

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We can figure out the true thrust now (T=thrust, a=air effect, in gm-wt)
T + a = -0.54
-T + a = +0.54/7
solving by eliminating ‘a’ gives
T = -0.31 gm-wt

so thrusting forward at the small end

Quote
the thrust downwards is around 7 times smaller. difference on the scale is only 0.20 grams

I'm confused.
From Iulian's quote, wouldn't Test 1 = 0.2*7=1.4g and Test 2 = 0.2 . Then the equation would be set up like this?
T=thrust
A=air

T+A=1.4g
T-A=0.2g
T=0.8g
A=0.6g
We are both wrong. He said two contradictory things
"I got 1/7th of the previous thrust, in the opposite direction" and
"I got 2 gm-wt thrust downwards"


Originally he got 0.54 gm-wt upwards, so 1/7th would be 0.08 - yet he says 0.2
I'll go with 0.2. T assumed towards small end.

T + A = 0.54 (up)
-T + A = -0.2 (down)

Solving:
T = 0.37 (thrusts from small end)
A = 0.17 (~50% of the thrust)


Of course, Iulian is welcome to come and correct both of us, but from rewatching his video of test 3, I see that his scale registers around 1.4 when he turns the magnetron on, which is about 7x this new amount. Perhaps he is talking about 0.2 gm registering on the scale itself, not the multiplied amount taking into account the lever multiplier.

Offline Iulian Berca

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I just uploaded the video with the upside down test.  in the next days i will start testing the new setup with the adjustable length.


Offline TheTraveller

This is also interesting for TM010 mode. Note where the H (magnetic) field is located. At the big end, right where Shawyer feeds in the Rf in the Demonstrator & Flight Thruster EM Drives.

Backs up the Patent mention of TM01 mode.

Fairly clear to me, TM010 is probably Shawyers EM Drive mode.
« Last Edit: 05/21/2015 08:15 PM by TheTraveller »
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Online Rodal

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...

The use of HDPE rather than PTFE at MW freqs has been bothering me. Nowhere over 1 GHz have I heard of HDPE, which could indicate high moisture absorption or reflectability. Also, the melting point of HDPE is rather low compared to the 250 deg C of PTFE.

The comparison tables are here: http://www.vanderveerplastics.com/compare-materials.html?sel1=hdpe&sel2=teflon-ptfe-fep

If someone knows why HDPE (typically plastic milk jugs( were initially used, it would be interesting.

"High-density polyethylene (HDPE) or polyethylene high-density (PEHD) is a polyethylene thermoplastic made from petroleum. It is sometimes called "alkathene" or "polythene" when used for pipes.[1] With a high strength-to-density ratio, HDPE is used in the production of plastic bottles, corrosion-resistant piping, geomembranes, and plastic lumber. HDPE is commonly recycled, and has the number "2" as its resin identification code (formerly known as recycling symbol)." per http://en.wikipedia.org/wiki/High-density_polyethylene

HDPE has very interesting properties, it has been used for biomedical applications, for garbage bags and countless commercial applications. It is very tough, it has excellent sliding abrasion resistance and is self lubricating.

As to why it was used as a dielectric for NASA's EM Drive, my recollection is that it was based on prior experience by Paul March, originally working with Prof. Woodward on his Mach Effect theory and experiments, and that it was based, as I noted above, on the imaginary properties acting as absorption coefficients in electromagnetic waves.

By the way, NASA also used PTFE and Nitrile Rubber as dielectrics.  They obtained the highest thrust force with HDPE
« Last Edit: 05/21/2015 08:34 PM by Rodal »

Offline TheTraveller

The bottom line is that nobody understands how this thing works.

Once we have solid build dimensions & BOM, working out if it works as per Shawyer & Chinese or not theories should not take long.
« Last Edit: 05/21/2015 08:13 PM by TheTraveller »
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Offline deltaMass

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I just uploaded the video with the upside down test.  in the next days i will start testing the new setup with the adjustable length.


Great! You got a thrust reversal.
T + A = 0.508 gm-wt
-T + A = -0.072 gm-wt
so
T = 0.290 gm-wt (thrust forward from small end)
A = 0.218 gm-wt (air deltaMass comparable in magnitude to thrust, unfortunately)


Interesting that the thrust seems to be "small end forward". Others (Shawyer, NASA, Juan) see opposite thrust, from the large end.
« Last Edit: 05/21/2015 08:48 PM by deltaMass »

Offline Notsosureofit

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Take a gander at the section on energy conservation here:

http://emdrive.echothis.com/Generic_EM_Drive_Information


Just thinking that maybe there should be a third option:  Since a constant acceleration transforms as a 4-space rotational velocity (?), there may be an invariant for the tensor which allows Energy to Momentum conversion. ?  This would be what, a "false force" driven by the dispersion cycle in the cavity ??  I'm visualizing that cycle as distorted compared to symmetrical cavity which would want to make it (the world line) curve in x,t.
« Last Edit: 05/21/2015 08:31 PM by Notsosureofit »

Online Rodal

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This is also interesting for TM010 mode. Note where the H (magnetic) field is located. At the big end, right where Shawyer feeds in the Rf in the Demonstrator & Flight Thruster EM Drives.

Backs up the Patent mention of TM01 mode.

Fairly clear to me, TM010 is probably Shawyers EM Drive mode.
What is clear is that TM010 is definitely not the mode shape at the reported frequency and dimensions of Shawyer's Flight Thruster

Even at the lower frequency (almost 1/2 of the Flight Thruster) used by NASA Eagleworks (below 2 GHz with a dielectric) they are into a much higher mode shape: TM212

and look at the natural frequency shown on the image you posted above for NASA Eagleworks: TM010 is below 1 GHz without a dielectric
« Last Edit: 05/21/2015 08:36 PM by Rodal »

Offline TheTraveller

This is also interesting for TM010 mode. Note where the H (magnetic) field is located. At the big end, right where Shawyer feeds in the Rf in the Demonstrator & Flight Thruster EM Drives.

Backs up the Patent mention of TM01 mode.

Fairly clear to me, TM010 is probably Shawyers EM Drive mode.
What is clear is that TM010 is definitely not the mode shape at the reported frequency and dimensions of Shawyer's Flight Thruster

Just think about it, even at the lower frequency used by NASA Eagleworks (below 2 GHz with a dielectric) they are into a much higher mode shape: TM212

and look at the natural frequency shown on the image you posted above for NASA Eagleworks: TM010 is below 1 GHz without a dielectric

The EW frustum is not the Flight Thruster. When I wake, will mod the SS with the TM01 cutoff equation & see what I will see.
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Interesting that the thrust seems to be "small end forward". Others (Shawyer, NASA, Juan) see opposite thrust, from the large end.

All tests move towards the small end, including these new tests.  I don't think anyone was shown movement toward the large end... ???

Online Rodal

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Interesting that the thrust seems to be "small end forward". Others (Shawyer, NASA, Juan) see opposite thrust, from the large end.

All tests move towards the small end, including these new tests.  I don't think anyone was shown movement toward the large end... ???
With the possible exception of Prof. Yang in China.

I may not recall this correctly since I have not read those papers in a long time.  Can somebody point out to an explicit reference showing actual measurements (not the computer simulations by Yang) of which way did Yang's device move ?

Notice that in this chart (by Shawyer), Prof. Yang's thruster and Shawyer's Flight Thruster are shown with measurements in the opposite direction:

« Last Edit: 05/21/2015 09:10 PM by Rodal »

Offline ThereIWas3

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What I want to know is, can a web site be nominated for the Nobel Prize in physics?
Or does Shawyer et all get all the glory when this pans out?

 :)
"If you want to build a ship, don’t drum up people to collect wood and don’t assign them tasks and work, but rather teach them to long for the endless immensity of the sea" - Antoine de Saint-Exupéry

Offline Taven

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It seems the confusion over thrust direction is stemming from people defining the word thrust to mean "pushing out of the back" or "thrusting in the forward direction".

Offline deltaMass

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I think "small end forward" resolves ambiguity

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