Author Topic: EM Drive Developments Thread 1  (Read 763242 times)

Offline raketa

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Re: EM Drive Developments
« Reply #1180 on: 09/30/2014 08:25 PM »
Rejoice and be glad, because great is your reward in heaven...

Yeah sure.  That's what they told Osama Bin Laden:

When OBL died, George Washington met him at the Pearly Gates. He slapped him across the face and yelled, "How dare you try to destroy the Nation I helped conceive?"

Patrick Henry approached, punched him in the nose and shouted, "You wanted to end our liberties but you failed."

James Madison followed, kicked him in the groin and said, "This is why I allowed our government to provide for the common defense!"

Thomas Jefferson was next, beat Osama with a long cane and snarled, "It was evil men like you who inspired me to write the Declaration of Independence. "

The beatings and thrashings continued as George Mason, James Monroe and 66 other early Americans unleashed their anger on the radical, socialist, leader.

As Osama lay bleeding and in pain, an Angel appeared. Osama wept and Said, "This is not what you promised me."

The Angel replied, "I told you there would be 72 VIRGINIANS waiting for you in Heaven. What did you think I said?"
really funny good job

Offline raketa

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Re: EM Drive Developments
« Reply #1181 on: 09/30/2014 08:37 PM »
Raketa, read back in the thread a ways, this is not a good idea. Current thrust level for both what Eagleworks and Woodward have studied are too low, and more importantly too inconsistent& not sustained, to provide sufficient impulse to see some an unquestioned effect in orbit, especially in high-drag environment like ISS altitude.
Ion engine thrust 20-250mN
Dragon solar panels could deliver 2kW power.
Chinese claim 720mN with 2.5 kW
NASA               91uN with just 0.017kW
Are you it will be not possible indicate slowing of decay Dragon trunk?

Online RotoSequence

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Re: EM Drive Developments
« Reply #1182 on: 09/30/2014 08:41 PM »
Raketa, read back in the thread a ways, this is not a good idea. Current thrust level for both what Eagleworks and Woodward have studied are too low, and more importantly too inconsistent& not sustained, to provide sufficient impulse to see some an unquestioned effect in orbit, especially in high-drag environment like ISS altitude.
Ion engine thrust 20-250mN
Dragon solar panels could deliver 2kW power.
Chinese claim 720mN with 2.5 kW
NASA               91uN with just 0.017kW
Are you it will be not possible indicate slowing of decay Dragon trunk?

I think the problem with choosing to fund them now is the present absence of delineation between interactions with the torsion pendulum and actual thrust. Satellite power is not a problem.
« Last Edit: 09/30/2014 08:42 PM by RotoSequence »

Online Rodal

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Re: EM Drive Developments
« Reply #1183 on: 09/30/2014 09:06 PM »
Raketa, read back in the thread a ways, this is not a good idea. Current thrust level for both what Eagleworks and Woodward have studied are too low, and more importantly too inconsistent& not sustained, to provide sufficient impulse to see some an unquestioned effect in orbit, especially in high-drag environment like ISS altitude.
Ion engine thrust 20-250mN
Dragon solar panels could deliver 2kW power.
Chinese claim 720mN with 2.5 kW
NASA               91uN with just 0.017kW
Are you it will be not possible indicate slowing of decay Dragon trunk?

I think the problem with choosing to fund them now is the present absence of delineation between interactions with the torsion pendulum and actual thrust. Satellite power is not a problem.
And

THRUST force =5*10^(-5) N to 9*10^(-5) N demonstrated for less than 40 seconds pulse duration
« Last Edit: 09/30/2014 09:17 PM by Rodal »

Online Rodal

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Re: EM Drive Developments
« Reply #1184 on: 09/30/2014 09:20 PM »
Raketa, read back in the thread a ways, this is not a good idea. Current thrust level for both what Eagleworks and Woodward have studied are too low, and more importantly too inconsistent& not sustained, to provide sufficient impulse to see some an unquestioned effect in orbit, especially in high-drag environment like ISS altitude.
Ion engine thrust 20-250mN
Dragon solar panels could deliver 2kW power.
Chinese claim 720mN with 2.5 kW
NASA               91uN with just 0.017kW
Are you it will be not possible indicate slowing of decay Dragon trunk?

I think the problem with choosing to fund them now is the present absence of delineation between interactions with the torsion pendulum and actual thrust. Satellite power is not a problem.
And

NASA Tapered Cavity THRUST force =5*10^(-5) N to 9*10^(-5) N demonstrated for less than 40 seconds pulse duration

And

NASA Tapered Cavity not tested in a vacuum

Offline Notsosureofit

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Re: EM Drive Developments
« Reply #1185 on: 09/30/2014 10:34 PM »
Been trying to get my head around axions.
1.  Not sure I understand why axions should all have the same mass.  Could be related to the guess that they might form a Bose-Einstein condensate?
2.  A Bose-Einstein condensate would certainly take care of the mass coupling problem.
3.  The coupling constant is the same in both directions:
axion->photons, photons->axion.
4.  The symmetry/asymmetry of the particle/anti-particle is confusing, but there is something rattling around in my memory about that. (later)
5.  A positive result from the Axion Dark Matter eXperiment (ADMX) would have a high degree of confidance in my mind, at least.

Offline Notsosureofit

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Re: EM Drive Developments
« Reply #1186 on: 09/30/2014 11:24 PM »
Another interesting paper: http://arxiv.org/pdf/1403.5676.pdf

OK, here's the Bose-Einstein paper: http://arxiv.org/pdf/0901.1106v4.pdf

« Last Edit: 09/30/2014 11:38 PM by Notsosureofit »

Online Rodal

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Re: EM Drive Developments
« Reply #1187 on: 09/30/2014 11:40 PM »
Another interesting paper: http://arxiv.org/pdf/1403.5676.pdf

<<The observed Shapiro step anomalies of all four experiments consistently point towards an axion mass of 110*10^(-6) eV.>>

This mass is in the range that the ADMX experiment will be looking for in the future, but has not yet done so.

It is in the "B" region of the picture below.

It is in the region between what the ADMX experiment and CERN Telescope's have looking at.

It would explain why they haven't find the Axion (Dark Matter) yet.

The frequency that ADMX will use, ~30GHZ is about 15 times higher than the frequency at which NASA Eagleworks run the microwave devices. (Eagleworks run the Frustrum at 1.94 GHz).
« Last Edit: 09/30/2014 11:56 PM by Rodal »

Online Rodal

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Re: EM Drive Developments
« Reply #1188 on: 10/01/2014 12:11 AM »
OK, here's the Bose-Einstein paper: http://arxiv.org/pdf/0901.1106v4.pdf

So, as I see this it would work like Dr. White's momentum-transfer model within a "sea of weakly-interacting particles surrounding the outside and the inside of the spacecraft" with the following big changes (Cold Dark Matter instead of Quantum Vacuum virtual particles):

Quantum Vacuum Plasma--> Bose-Einstein Condensate of Axions  (but both acting as a "compressible fluid" in Dr. White's conceptual model)

electron-positron virtual particle pair --> Axions (Cold Dark Matter)

Unresolved issues: 

A) Four experiments consistently point towards an axion mass of 110*10^(-6) eV.  This mass implies a microwave frequency for ADMX experiment of ~30GHZ or about 15 times higher than the frequency at which NASA Eagleworks run the Truncated Cone Cavity (1.94 GHz).

B) The NASA Eagleworks experiments are missing the ~3 T magnetic field surrounding the microwave cavity.  The only magnetic field in the Eagleworks  experiments is the one produced by the three neodymium (NdFeB Grade N42) block magnets, which are there only by chance ( to dampen the swinging and torsional oscillations of the inverted pendulum).  The magnetic damper is located about a foot away from the tested microwave device (Cannae or Frustum). The magnetic field intensity at the surface of a neodymium magnet is 1.25 T

Still, it makes much more sense than the "exotic" theories: a real particle (axions) from the exterior exchanging real momentum with the photons and not interacting with the metal walls of the cavity:

<<
2. A Bose-Einstein condensate would certainly take care of the mass coupling problem.
3.  The coupling constant is the same in both directions: axion->photons, photons->axion.
>>

It doesn't present the much greater difficulties associated with Woodward's theory and the Quantum Vacuum theory.
« Last Edit: 10/01/2014 02:21 AM by Rodal »

Online Rodal

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Re: EM Drive Developments
« Reply #1189 on: 10/01/2014 02:20 AM »
OK, here's the Bose-Einstein paper: http://arxiv.org/pdf/0901.1106v4.pdf
Is there an estimate of what would be the effective density (mass over occupied volume) of the Bose-Einstein condensate of axion Cold Dark Matter?

Online Rodal

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Re: EM Drive Developments
« Reply #1190 on: 10/01/2014 02:50 AM »
OK, here's the Bose-Einstein paper: http://arxiv.org/pdf/0901.1106v4.pdf
Is there an estimate of what would be the effective density (mass over occupied volume) of the Bose-Einstein condensate of axion Cold Dark Matter?

From http://arxiv.org/pdf/1403.5676.pdf   

according to page 5:

<<estimate the axion mass as 110 eV and the axionic dark matter energy density near the earth is rho = 0.051GeV/m^3>>

But according to page 1:

<<An experiment by Ho mann et al. based on S/N/S Josephson junctions [20], discussed in detail in [14], provided evidence for an axion mass of 110 eV and an axionic dark matter density of about 0.05 GeV/cm^3>>

Although the mass estimates agree 100%, there is a difference of 1 million between these two density numbers (notice the difference between cubic centimeters and cubic meters in the denominators).  The larger number (0.05 GeV/cm^3) makes more sense to me, as the lower number (0.05 GeV/m^3) is even lower than the measured density of the quantum vacuum.
« Last Edit: 10/01/2014 03:26 AM by Rodal »

Online Rodal

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Re: EM Drive Developments
« Reply #1191 on: 10/01/2014 12:24 PM »
Here is a paper written to describe the Casimir energy between a metallic plate and a dielectric plate within a cavity. The configuration is somewhat similar to the Tapered Cavity tested at EagleWorks.

http://math.scichina.com:8081/sciAe/EN/abstract/abstract377962.shtml#

I wonder if someone can help interpret this paper. To me, it does not seem consistent with what has been published elsewhere, in particular I see an unfamiliar term

Quote
where -pi/(24a^2) is the Casimir force between two ideal conducting plates separated by a.

But also this paper is developed in a reference system where c=1, h-bar=1. That is a common system but how does one convert the results into standard units of measure.

I forgot, if I ever knew how.

http://en.wikipedia.org/wiki/Speed_of_light

http://en.wikipedia.org/wiki/Planck_constant

Well yes I know that, but the author uses "1" in the equations derivation for each of these terms so where do I substitute the real values back into the end result to get real measurable values? Am I forced to carefully follow the derivation through to the end then know where the c's and h-bars go? (numerator, denominator, power, etc.)

I just remembered that some particle physicists use a system (to simplify the equations) where the fundamental SI units (mass,length,time) {kg,m,s} are replaced by these other fundamental units (Planck's constant, speed of light, GeV),{h,c,GeV} where h=1.055*10^(-34) J, c=2.998*10^8 m/s and GeV=1.602*10^(-10) J.  Then, in the {h,c,GeV} "system", mass, length and time are no longer fundamental, but they get "units" as shown in the table below.  In that "system" h=c=1, because in that "system" h=1 unit (a fundamental unit in that system) and c=1 unit (another fundamental unit in that system).

Then, for example, Einstein's energy momentum equation E^2 = p^2 c^2 + m^2 c^4
becomes simply E^2 = p^2 + m^2

To convert back into SI units one has to reinsert everywhere the missing factors of h and c, using dimensional analysis.  Yes, I agree, it is a pain to do that, but you don't really have to know the derivation.  You just have to know what type of quantity (length, mass, time, energy, momentum, etc.) it is, and convert it back to SI units, using the appropriate factors of  h=1.055*10^(-34) J, c=2.998*10^8 m/s and GeV=1.602*10^(-10) J as required, so that the quantity has proper SI dimensions.

Quantity                       SI units                          {h,c,GeV}                                          h=c=1 "units"

Mass                             kg                                    GeV/c^2                                                     GeV
Length                           m                                    (GeV/(hc))^(-1)                               (GeV)^(-1)
Time                              s                                     (GeV/(h))^(-1)                                 (GeV)^(-1)
Momentum                   kg m s^(-1)                     GeV/c                                                         GeV
Energy                          kg m^2 s^(-2)                 GeV                                                            GeV

_________________

The only reason I remembered this was because I was getting my mind around the cold dark matter density, (see post above) and comparing it with the quantum vacuum energy density, I found out that some Internet sources express this density as (GeV)^4 instead of GeV/m^3.  The reason for this follows from the above, because Length in this "system" has "units" of GeV^(-1) hence volume has units of GeV^(-3) and hence energy density (and mass density) have units of GeV/(GeV^(-3)) = (GeV)^4
« Last Edit: 10/01/2014 01:21 PM by Rodal »

Offline Notsosureofit

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Re: EM Drive Developments
« Reply #1192 on: 10/01/2014 01:07 PM »
OK, here's the Bose-Einstein paper: http://arxiv.org/pdf/0901.1106v4.pdf

So, as I see this it would work like Dr. White's momentum-transfer model within a "sea of weakly-interacting particles surrounding the outside and the inside of the spacecraft" with the following big changes (Cold Dark Matter instead of Quantum Vacuum virtual particles):

Quantum Vacuum Plasma--> Bose-Einstein Condensate of Axions  (but both acting as a "compressible fluid" in Dr. White's conceptual model)

electron-positron virtual particle pair --> Axions (Cold Dark Matter)

Unresolved issues: 

A) Four experiments consistently point towards an axion mass of 110*10^(-6) eV.  This mass implies a microwave frequency for ADMX experiment of ~30GHZ or about 15 times higher than the frequency at which NASA Eagleworks run the Truncated Cone Cavity (1.94 GHz).

B) The NASA Eagleworks experiments are missing the ~3 T magnetic field surrounding the microwave cavity.  The only magnetic field in the Eagleworks  experiments is the one produced by the three neodymium (NdFeB Grade N42) block magnets, which are there only by chance ( to dampen the swinging and torsional oscillations of the inverted pendulum).  The magnetic damper is located about a foot away from the tested microwave device (Cannae or Frustum). The magnetic field intensity at the surface of a neodymium magnet is 1.25 T

Still, it makes much more sense than the "exotic" theories: a real particle (axions) from the exterior exchanging real momentum with the photons and not interacting with the metal walls of the cavity:

<<
2. A Bose-Einstein condensate would certainly take care of the mass coupling problem.
3.  The coupling constant is the same in both directions: axion->photons, photons->axion.
>>

It doesn't present the much greater difficulties associated with Woodward's theory and the Quantum Vacuum theory.

The magnetic field is there to adjust the phase relationship between the photons (one is virtual in the Primicoff effect w/ particle interactions)  That's not the only way, the photons can have different frequencies.  The energy could be made up if 1 photon comes from the thermal IR present at room temperature.

Online Mulletron

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Re: EM Drive Developments
« Reply #1193 on: 10/01/2014 01:44 PM »
Found the below link while researching Unruh. I've been reading about this guy's theory of modified inertia called MiHsC. Here are his comments on emdrive:

http://physicsfromtheedge.blogspot.it/2014/09/emdrives-mihsc.html



Challenge your preconceptions, or they will challenge you. - Velik

Offline Ron Stahl

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Re: EM Drive Developments
« Reply #1194 on: 10/01/2014 01:51 PM »
I was suggesting first to proof/disproof in space, because lot of people thinking this is good idea, why we didn't try to make it happen.
I am putting my money where  my mouth is ready to pledge initial $1000 for this project.
1/Could we contact professor Dr Woodward if he will be interesting to participate and build his apparatus for space environment.
2/We have to find who will do crowdsourcing for us. Does anybody have experience or could recommend it somebody who has good reputation. . .
An in space demo is a TRL7 demo.  Woodward is at TRL5 right now.  Before you go to space, what you want is a phase 1, TRL6 demo that is very close to the commercial grade thruster you'd use for phase 2, TRL7--meaning similar in magnitude thrust (20 mN is fine if the FOM's are good), Figures of Merit (FOM's) for thrust to mass and thrust to power that can fly a spacecraft, thermal stability such that the thruster will work continuously in space where only black body radiation (T^4) can be used for cooling, and of course the continuous operation.  Woodward is currently a long way from these things, but these are the things I'm currently looking to finance through a DARPA grant if I can find the proper Principle Investigator.  Anyone who wants the job should let me know.  We already have a basic design that should meet all these above criteria.  PhD's in physics, electrical engineering, mechanical engineering, aerospace engineering and materials science will be considered. 

Note we're planning to run a concurrent project to develop our own proprietary radiation hardening technology that will allow all future spacecraft to fly through the Van Allen Belt undamaged.  Plasma physicists or anyone who thinks they have the qualifications for that project should likewise feel free to contact me.

Woodward is working on some crowdsourcing at present, but note that he is only concerned with proof of science, not proof of technology as this above.  He's not looking at a TRL7 demo while we're planning around one.  Note too that in-space demos are very expensive.  You not only can't do them on a hobby budget; you can't do them on a crowdsourcing budget.  It is millions of dollars to loft a spacecraft to LEO unless you use a nanosat, in which case you might get the launch for free, but you'll then have to pay for some expensive miniaturization, so its millions of dollars either way.
« Last Edit: 10/01/2014 02:13 PM by Ron Stahl »

Online Rodal

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Re: EM Drive Developments
« Reply #1195 on: 10/01/2014 02:17 PM »
Found the below link while researching Unruh. I've been reading about this guy's theory of modified inertia called MiHsC. Here are his comments on emdrive:

http://physicsfromtheedge.blogspot.it/2014/09/emdrives-mihsc.html

Thanks.  This is another interesting idea. It is more connected with Dr. White's thoughts about the quantum vacuum.
The problem is that Unruh's mathematical derivation is still very controversial.  Several physicists (i.e. http://link.springer.com/article/10.1134%2FS0021364009080025) state that Unruh's calculations improperly imposed boundary conditions at the horizon (stating that the decomposition of integrals over the entire range of the boost parameter into parts, as done by Unruh, is inapplicable ):

<<This means that the Unruh “effect” is absent for any statistics of particles. Thus, both the theoretical predictions and numerous proposals of experiments based on the assumption of the existence of this effect are unfounded.>>


_________

EDIT: I find amusing his description of the Shawyer (and NASA's "tapered cavity") drive as follows <<the EmDrive is .. a microwave oven built into a megaphone>>  :)
« Last Edit: 10/01/2014 03:17 PM by Rodal »

Offline JohnFornaro

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Re: EM Drive Developments
« Reply #1196 on: 10/01/2014 02:54 PM »
I've been watching Saturday morning cartoons.  Did I miss anything?

Hardy har har...
Sometimes I just flat out don't get it.

Offline wembley

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Re: EM Drive Developments
« Reply #1197 on: 10/01/2014 03:24 PM »
Can anybody provide a link to information from Roger Shawyer showing the dielectric material Shawyer uses, the dielectric shape and dimensions and the dielectric location ?

Have you tried asking him?

But I don't think he uses that approach any more:
"The first thruster built by SPR Ltd and tested in 2003 also used a dielectric section, but to obtain our subsequent high thrust levels, we abandoned the dielectric and concentrated on our present cavity design."


Online Rodal

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Re: EM Drive Developments
« Reply #1198 on: 10/01/2014 03:42 PM »
...Woodward is working on some crowdsourcing at present, but note that he is only concerned with proof of science, not proof of technology as this above.  He's not looking at a TRL7 demo while we're planning around one.  ..
Concerning only any possible technical reasons for your statement that "he is only concerned with proof of science, not proof of technology:"

Prof. Woodward obtained a patent with Thomas Mahood (http://www.google.com/patents/US6347766 ) (both as inventors and as assignees):

Publication number   US6347766 B1
Application number   US 09/549,475
Publication date   Feb 19, 2002
Filing date   Apr 14, 2000
Priority date   Jan 23, 1999

So, at that point in time, at least, he must have been interested in proof of technology, as the US Patent Office (from our Constitution) grants a patent, and hence a monopoly, to reward proof of such technology and its future development.   It is interesting that according to Google Patent Search:

Fee status:   Lapsed

for the above-mentioned patent.  (With the important Google disclaimer that this is not a legal conclusion).

It would be interesting if you could expand:

Does Prof. Woodward have other patents that superseded the above-mentioned patent?  If indeed the above information is correct that the fee status has lapsed, and if you are correct in stating that <<he is only concerned with proof of science, not proof of technology >> has anything changed technically since he originally obtained the above-mentioned patent that would motivate to concentrate now on proof of science, rather than proof of technology ?

Of course, there are shades of gray in all this, for example his source of funds at that point in time may have been the one pushing for a patent.  I am not interested in his personal motivations, I'm only interested in whether there are some technical reasons (for example the "bulk acceleration" issue, etc.) that may have produced a change of priorities concerning proof of technology.
« Last Edit: 10/01/2014 05:33 PM by Rodal »

Online Rodal

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Re: EM Drive Developments
« Reply #1199 on: 10/01/2014 03:50 PM »
...
But I don't think he uses that approach any more:
"The first thruster built by SPR Ltd and tested in 2003 also used a dielectric section, but to obtain our subsequent high thrust levels, we abandoned the dielectric and concentrated on our present cavity design."
Where is the above quotation from? (I would appreciate a link for it so that I can further understand the context)

Thanks for your response

_________
PS: I looked for it , but I could not find that statement in this 2006 report:   http://www.newscientist.com/data/images/ns/av/shawyertheory.pdf
« Last Edit: 10/01/2014 04:22 PM by Rodal »

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