Author Topic: EM Drive Developments Thread 1  (Read 765942 times)

Offline aero

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Re: EM Drive Developments
« Reply #1420 on: 10/05/2014 12:55 AM »
@frobnicat

What is the .01m˛ csection that you refer to?

Maybe you told us the definition of terms before but I didn't find them in the last 20 pages, yesterday.

I wonder, because that equals 100 cm^2 or a square about 4 inches on a side and I don't recognize that dimension wrt the thruster cavity.
« Last Edit: 10/05/2014 01:00 AM by aero »
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Offline Notsosureofit

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Re: EM Drive Developments
« Reply #1421 on: 10/05/2014 01:04 AM »
Hmm, old memories, the cross section for a high Q antenna (assuming the cavity doe not shield axions) is a lot larger than the physical size.  I don't remember the relation but it been a long, long time.

Offline aero

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Re: EM Drive Developments
« Reply #1422 on: 10/05/2014 01:29 AM »
Quote

2

down vote
 

According to Constraints on Dark Matter in the Solar System the following upper limits have been placed on dark matter in the solar system, based upon orbital motion of bodies in the solar system:

At the radius of Earth's orbit: 1.4×10 −19 g/cm 3 

At the radius of Mars's orbit: 1.4×10 −20 g/cm 3 

At the radius of Saturn's orbit: 1.1×10 −20 g/cm 3 

According to Local Density of Dark Matter, the density of dark matter at the Sun's location in the galaxy is 0.43GeV/cm 3   or 7.7×10 −25 g/cm 3 
 

http://arxiv.org/abs/1306.5534

http://arxiv.org/abs/1212.3670
« Last Edit: 10/05/2014 01:44 AM by aero »
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Offline Rodal

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Re: EM Drive Developments
« Reply #1423 on: 10/05/2014 01:57 AM »
Quote

2

down vote
 

According to Constraints on Dark Matter in the Solar System the following upper limits have been placed on dark matter in the solar system, based upon orbital motion of bodies in the solar system:

At the radius of Earth's orbit: 1.4×10 −19 g/cm 3 

At the radius of Mars's orbit: 1.4×10 −20 g/cm 3 

At the radius of Saturn's orbit: 1.1×10 −20 g/cm 3 

According to Local Density of Dark Matter, the density of dark matter at the Sun's location in the galaxy is 0.43GeV/cm 3   or 7.7×10 −25 g/cm 3 
 

http://arxiv.org/abs/1306.5534

http://arxiv.org/abs/1212.3670

Thanks @aero for this very interesting information

Wow

At the radius of Earth's orbit: 1.4×10 −19 g/cm 3

that is 7.868x10^4 GeV/cm^3 = 78680 GeV/cm^3

....
At about 1Gev/cm^3 (as seen on this seemingly optimistic paper, maybe more optimistic is possible) and .01m˛ csection and 250km/s dark flow velocity that is mflow=1e9*1.8e-36/1e-6 * 2.5e5 * 1e-2 = 4.5e-18 kg/s.
With about 45*µN thrusters that yields Vej = F / mflow = 4.5e-5 / 4.5e-18 = 1e12m/s   ???
Pow = .5 mflow Vej˛ = :D = .5 * 4.5e-18 * 1e24 = 2.25 e6 = 2.25MW hence the 6 orders of magnitude boast (more like 5 actually with those numbers) when comparing to 20W power.
...

So @frobnicat used  1Gev/cm^3  which is 78680 times less than this estimate !

***there is also the question about the square cross section, previously posted by @aero ***

So now we are now much closer to the ballpark

« Last Edit: 10/05/2014 02:22 AM by Rodal »

Offline ThinkerX

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Re: EM Drive Developments
« Reply #1424 on: 10/05/2014 02:41 AM »
Quote
So @frobnicat used  1Gev/cm^3  which is 78680 times less than this estimate !

***there is also the question about the square cross section, previously posted by @aero ***

So now we are now much closer to the ballpark

So 'microwave photon created dark matter axioms' are now a leading candidate for an explanation of the physics behind the Eagleworks thruster?  Looking for clarity here.  The revised Dark Matter numbers appear...close(?) to what is required, anyhow.

Also, monumentally stupid, maybe, but I'll ask anyhow.  Even a superficial surface looksee into Dark Matter reveals...informed speculation(?)...of a whole zoo of Dark Matter particles.  Maybe some of them have a bigger 'kick' than others?

Offline Rodal

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Re: EM Drive Developments
« Reply #1425 on: 10/05/2014 02:55 AM »
Quote
So @frobnicat used  1Gev/cm^3  which is 78680 times less than this estimate !

***there is also the question about the square cross section, previously posted by @aero ***

So now we are now much closer to the ballpark

So 'microwave photon created dark matter axioms' are now a leading candidate for an explanation of the physics behind the Eagleworks thruster?  Looking for clarity here.  The revised Dark Matter numbers appear...close(?) to what is required, anyhow.

Also, monumentally stupid, maybe, but I'll ask anyhow.  Even a superficial surface looksee into Dark Matter reveals...informed speculation(?)...of a whole zoo of Dark Matter particles.  Maybe some of them have a bigger 'kick' than others?
Not much time to write now, but situation:

1) closest estimate is the one based on Unruth radiation
2) yes using the above mentioned estimate of dark matter + what @notsosureofit pointed out, axionic dark matter is a coherent explanation that is not so far away from the measurements

Have to run...
« Last Edit: 10/05/2014 03:05 AM by Rodal »

Offline aero

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Re: EM Drive Developments
« Reply #1426 on: 10/05/2014 03:21 AM »
Quote
So @frobnicat used  1Gev/cm^3  which is 78680 times less than this estimate
question about the cross section,

I have no idea how the cross section should be estimated. I followed frobnicat's calculations but used the area of the small end of the truncated frustum thruster, which is about 0.044 m^2, and the density number above.

I calculate mflow= 1.55786E-12 kg/s compared to the earlier value of 4.5e-18 kg/s.

Of course I'm not even sure frobnicat was considering the truncated frustum thruster, he may be considering the Cannae device.
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Offline aero

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Re: EM Drive Developments
« Reply #1427 on: 10/05/2014 04:27 AM »
Quote
So @frobnicat used  1Gev/cm^3  which is 78680 times less than this estimate
question about the cross section,

I have no idea how the cross section should be estimated. I followed frobnicat's calculations but used the area of the small end of the truncated frustum thruster, which is about 0.044 m^2, and the density number above.

I calculate mflow= 1.55786E-12 kg/s compared to the earlier value of 4.5e-18 kg/s.

Of course I'm not even sure frobnicat was considering the truncated frustum thruster, he may be considering the Cannae device.

Tried to modify that post but somehow the modification was lost.

Continuing to substitute values into frobnicat's calculations, I calculate a value of Vej = 2.8886.E+07 m/s
so power = .5 mflow*Vej^2 = 6.4993.E+02 or 650 watts.

Hmm - How again did someone explain the lack of energy conservation? Or does the device scoop up enough dark matter (like an antenna) so that mass is higher, Vej is lower and energy is more like 17 watts?

I will calculate some more.

Edit add:

I get, roughly, these values using classic math,
momentum = mass*velocity and energy = .5 mass* velocity squared.

Vej, m/s   mflow, kg/s   power, watts
7.60E+05   5.92E-11   1.71E+01
9.00E+05   5.00E-11   2.03E+01

With these mass and velocity numbers, energy is conserved.
« Last Edit: 10/05/2014 04:46 AM by aero »
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Offline Mulletron

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Re: EM Drive Developments
« Reply #1428 on: 10/05/2014 07:03 AM »
Revised things a bit to further constrain extrinsic mechanisms between extrinsic Machian and extrinsic but local perturbations giving rise to inertial mass. Also I got Bergman wrong the first time. It sounds intrinsic to me; intrinsic but not fundamental, it is emergent.

With De Broglie, I'm putting it in both extrinsic camps solely from remembering that elementary particles don't self interact, but (and correct me if I'm wrong here) saying that elementary particles don't self interact is too wide of a brush stroke because CHARGED elementary particles clearly do. An electron is the same as any other electron for example and they are like charged and would repel. This ties in with the "there is only 1 electron in the universe  kind of thinking" but I'll expand on this later on when I get my facts straight about Wheeler Feynman absorber theory. If this works out, I'm putting any theory that relies on any charged particle and its associated field in both camps, because these fields also have a vacuum component that plays by same rules of interaction.

Intrinsic:
Higgs: Rest mass/energy contribute to inertial mass and rest mass because GR predicts they are equivalent.
Newton: It is intrinsic because I said so. It just is.
Bergman: Inertia is a real force arising from electrodynamics of moving particles. Force depends on velocity an acceleration.

Extrinsic Machian:
EM ZPF, Haisch et al
Unruh zpf/casimir McCulloch et al
De Broglie Compton resonance Haisch Reuda
Cosmic gravity-Mach
Cosmic gravity modified by Wheeler/Feynman, -Sciama-Woodward



Extrinsic local pertubation:
De Broglie Compton resonance Haisch Reuda

http://www.google.it/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CC8QFjAC&url=http%3A%2F%2Fwww.commonsensescience.org%2Fpdf%2Farticles%2Finertial_mass.pdf&ei=GOAvVIPWJYSrPJnogIAG&usg=AFQjCNGT5DXFojND6Ft_jpIj4_wg-bhmIQ&bvm=bv.76802529,d.ZWU&cad=rja

http://www.calphysics.org/inertia.html
« Last Edit: 10/05/2014 06:28 PM by Mulletron »
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Offline Mulletron

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Re: EM Drive Developments
« Reply #1429 on: 10/05/2014 07:21 AM »
I'm just going to keep editing this post as a living document until I get my thoughts ironed out.

So my project today is to try and see if I can exclude Wheeler–Feynman absorber theory (which I'm not so completely critical of anymore, see very bottom) from being a logical component of Machian derived theories. I don't have the facts straight yet because I really don't have a firm understanding of the complex interactions of how T symmetry is broken in the electroweak realm, combined with the statements in my previous post. Basically what I'm grasping for is the point where T symmetry breaks and its relation to where mass arises (creating gravity) and to where charge arises.

Part of my problem is that I literally treat EVERYTHING as a wave, particle, and field at the same time. And for the quantum stuff I add a 2d probability distribution to that field in to visualize mass/energy (basically a 2d photo of a wave function) with a spike where the mass/energy is and in 3d as a simple random cloud where probability affects size/shape. When I'm taking charge into account, I take the 2d probability distribution I just mentioned and flip it 180 degrees so opposite charges cancel. Things make sense most of the time that way. (Maybe I need to change something about how I think.)

It is probably obvious to the whole world but me. It is keeping me up at night and I'm falling behind following up on other poster's comments and ideas that are pretty darn good too.

---(work in progress) So I can clearly picture how a photon and it's associated wave function can extend both forward and and back in time, now) In the context of the "infinite" universe, If I take an arbitrary particle/wave function and place it there across the cosmos, there is clearly no way to find a "present" in the context of spacetime. This works out for me with any photon because photons don't self interact and there is no rebound to worry about; no dissipative force or damping term is needed, but when I try to apply that to say an electron (which has charge) and it's associated field, it all falls apart for me. Charge really kills it for me.

When you accelerate an electron, it will give off EM radiation in the form of photons (which I just talked about above and get I it) with a wave function, the energy of that photon depends on the magnitude of acceleration and lasts for the duration of the acceleration as a response to the increase in momentum the electron has from being accelerated. Just conservation of energy, giving away energy in EM for a gain in kinetic energy.

Here's what this is all about:
---Does rest mass arise before, during/because or after T-symmetry is broken.

I clearly don't understand things.

Mass is what gives rise gravity. According to GR, inertial mass and rest mass are equivalent. (Not close, the same, fundamentally. is this assumption correct?) Theories which use Wheeler-Feynman to explain inertial mass, would require the use of fields which give rise to mass, but these particles self interact. Quarks very strongly interact with other quarks via gluons......Where am I going with this....lost it..break time.

brainstorming bs and work to do below
-Charge....
-Color charge......
-Justification for saying particles self interact....and why every other electron is equivalent
-What's really accelerating anyway (everything? if so that means absolute frame of reference is set by Hubble boundary condition, that would be convenient so first I'm accelerating wrt the universe, then/second, the stuff around me), given black body radiation, universe expansion, but QV doesn't get diluted as universe expands.....Points to consider that there are no absolute reference frames, It is a fact. Not trying to undo Einstein here but instead extrapolate all the details and implications of this... meaning there are no places in the universe which are completely not moving. Which celestial objects are accelerating vs which ones are NOT? And accelerating with respect to what? The center of our galaxy? Are the stars at the edge of our galaxy really undergoing very close to zero acceleration wrt the center of the galaxy? What accounts for the small acceleration that is left? The huge distance from the center of the galaxy? Meaning the curve of spacetime is very small, ie very small acceleration. Tentative conclusion, is there are no preferred reference frames=true, within galaxies. Between galaxies.....=true, the reference frame becomes the motion of all the other galaxies moving toward/away from you/who's to say you aren't accelerating toward them?=true. There are continuously collapsing layers of reference frames extending from the very large to the very small, each of which an observer can appear to be inertial, but it is an illusion and only true locally/not globally. Darn near everything is accelerating toward something else. So what?

-notes:
energy and momentum which are primary generators of gravity at high energies/accelerations, not mass
-massless: photons, gluons, gravitons
-massive: W and Z, quarks, electrons, muons, taus, some neutrinos, higgs

-w,z,quarks, leptons only get mass from the higgs.
-higgs gets mass from somewhere else...






« Last Edit: 10/05/2014 12:32 PM by Mulletron »
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Offline frobnicat

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Re: EM Drive Developments
« Reply #1430 on: 10/05/2014 11:04 AM »
@frobnicat

What is the .01m˛ csection that you refer to?

Maybe you told us the definition of terms before but I didn't find them in the last 20 pages, yesterday.

I wonder, because that equals 100 cm^2 or a square about 4 inches on a side and I don't recognize that dimension wrt the thruster cavity.

This was a very crude order of magnitude number to start from. The tested devices are not 1m^3 volume nor 1cm^3, so I started at 1000cm^3, round (not flat) volume that is about 100cm^2 as seen from a passing flow. The real dimensions of devices are a bit above that : feel free to plug better numbers.

Obviously there would be a coupling factor  "harvested dark mass flow" = coupling * "incoming dark mass flow". I made the very very optimistic assumption that coupling = 1, which for notoriously shy particles is a bit of a stretch, to get an upper bound of thrust from naturally occurring dark matter. I guess there is a lot of unknown on such a coupling, but negative results from DM detection experiments indicate that it must be <<1. It would also depend on the particular details, depth of interacting volume... so this is a huge unknown between 0 and 1 but probably very near 0. If assumed as best case 1, my calculations show that, at best, this is still far from enough with 1GeV DM density and on the order of 100s km/s DM "wind".

For the later, answering my own question of "how hot is hot dark matter, could it be relativistic" I would say obviously not : DM particles speed can't be much above galactic escape velocity about 500km/s otherwise they would quickly evaporate from galaxy and not stick with it (as it appear from their gravity contribution).

So in the expression of DM mass flow, the flow velocity term can't be pushed much higher.


Offline frobnicat

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Re: EM Drive Developments
« Reply #1431 on: 10/05/2014 11:44 AM »
To be clear...
using naturally occurring dark matter at 1Gev/cm^3 and a "round" 1000cm^3 device with near 100% DM harvesting capability :

- Sailing : we harvest particles at their incoming velocity (<600 km/s) and be pushed by them -> pico Newtons

- Propeller/slow wind : power of the device is used to accelerate DM particles. Incoming velocity is irrelevant (for energy) since Vej would be relativistic to get enough thrust from such a low mass flow. This is worthless to use DM slow mass then, since the ejected imparted kinetic energy >> energy equivalent of rest mass: better just make photons from your available power source and ignore DM entirely.

- Perfect mass to energy conversion + photon drive : we harvest particles at their incoming velocity (<600 km/s) and convert rest mass to energy (the 600km/s kinetic energy is irrelevant here compared to mc˛) and use that power to push on photons (or any other light particle with relativistic ejection velocity) -> nano Newtons

1Gev/cm^3 is optimistic from what I understand. I'll look for the much higher upper bounds...
Note the stringent conditions for the later best case, underlined.

Offline Rodal

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Re: EM Drive Developments
« Reply #1432 on: 10/05/2014 12:18 PM »
Took a while to find this again.
http://www.gregegan.net/SCIENCE/Cavity/Cavity.html
The NASA Eagleworks report shows that the resonant mode shape of operation is more important than the Q factor

<<B. Tapered Cavity RF Evaluation and Testing, First TM211 mode
Figures 18 and 19 chronicle the activities surrounding a series of five test runs at 1932.6 MHz corresponding to the first TM211 mode. In this test configuration, the VNA system indicated a quality factor of ~7320, and the difference of power forward and power reflected as reported by the power meters was indicated to be ~16.92 watts as a result of manual tuning to maximize the power difference. The (net) peak thrust observed for this tested configuration was 116 micronewtons and the (net) mean thrust over the five runs was 91.2 micronewtons.>>

<<C. Tapered Cavity RF Evaluation and Testing, Second TM211 mode
COMSOL® analysis indicates that there are two TM211 modes within a couple of MHz of one another for the as-built tapered thruster. The higher frequency TM211 mode has a much higher predicted quality factor (32,125), but considerably lower thrust to power performance (5 micronewtons per watt). The tapered RF system was tuned and operated at this mode for evaluation on the low thrust torsion pendulum. The measured quality factor was 18,100 with a power-forward/power-reflected difference of 16.74 watts and the average measured thrust was 50.1 micronewtons. With an input power of 16.74 watts, correcting for the quality factor, the predicted thrust was 47 micronewtons.>>

Unfortunately, the NASA report only shows the frequencies, but it does not show the mode shapes.  One cannot tell why a frequency of only  four MHz higher has a Q more than 4 times higher but a thrust force half as much as the lower frequency. It would be nice to have a picture of the mode actual mode shapes (as shown in the reference submitted by Mulletron http://www.gregegan.net/SCIENCE/Cavity/Cavity.html for a different geometry) to tell what is the difference in the mode shapes: what gets excited in the cavity at the 4 MHz lower mode shape that makes such a big difference.

Or is the thrust force (twice higher) at the 4 MHz lower frequency not really due to the mode shape but is it due to something happening in the dielectric resonator and/or coupling with something (dark matter for example)?

COMSOL® field plot for 1932.6 MHz, TM211 also shown for reference - red is electric, blue is magnetic
« Last Edit: 10/05/2014 12:50 PM by Rodal »

Offline Notsosureofit

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Re: EM Drive Developments
« Reply #1433 on: 10/05/2014 12:33 PM »
Havn't been able to find the resonant formula I was looking for, but some interesting things in the old radar handbook.  The only point of interest for axion interaction in this setup is that surface effects can change the geometric cross-section from -12db to +28db in the optical region where wavelength is small compared to size.  The response of a bulk dielectric is noisy but only a few db around geometric area.

Edit: no real surprise about the proper mode being important.
« Last Edit: 10/05/2014 12:40 PM by Notsosureofit »

Offline Rodal

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Re: EM Drive Developments
« Reply #1434 on: 10/05/2014 12:58 PM »
Havn't been able to find the resonant formula I was looking for, but some interesting things in the old radar handbook.  The only point of interest for axion interaction in this setup is that surface effects can change the geometric cross-section from -12db to +28db in the optical region where wavelength is small compared to size.  The response of a bulk dielectric is noisy but only a few db around geometric area.

Edit: no real surprise about the proper mode being important.
If there is "no real surprise about the proper mode" shape being important, then we have to rethink the importance of the cavity.
@notsosureofit & @mulletron: any thoughts about the following ?:

Concerning the tapered cavity, maybe the geometry (not a perfect truncated cone, and notice the off center inner circle in the COMSOL vector plot I attached) is not that trivial: what could be the drastic difference in mode shapes with these two frequencies,  1932 and 1936 MHz that result in differences in thrust of a factor of 2 ?

COMSOL® field plot for 1932.6 MHz, TM211 also shown for reference - red is electric, blue is magnetic
« Last Edit: 10/05/2014 01:05 PM by Rodal »

Offline Notsosureofit

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Re: EM Drive Developments
« Reply #1435 on: 10/05/2014 01:05 PM »
Modes determine the E,B field intensities at all the surfaces.  Yes you need to include the dielectric.  And if the dielectric interface is where any interaction takes place, that could explain the COMSOL model. (not that they mentioned the mode they used in the model)

Offline Mulletron

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Re: EM Drive Developments
« Reply #1436 on: 10/05/2014 01:12 PM »
Took a while to find this again.
http://www.gregegan.net/SCIENCE/Cavity/Cavity.html
The NASA Eagleworks report shows that the resonant mode of operation is more important than the Q factor

<<B. Tapered Cavity RF Evaluation and Testing, First TM211 mode
Figures 18 and 19 chronicle the activities surrounding a series of five test runs at 1932.6 MHz corresponding to the first TM211 mode. In this test configuration, the VNA system indicated a quality factor of ~7320, and the difference of power forward and power reflected as reported by the power meters was indicated to be ~16.92 watts as a result of manual tuning to maximize the power difference. The (net) peak thrust observed for this tested configuration was 116 micronewtons and the (net) mean thrust over the five runs was 91.2 micronewtons.>>

<<C. Tapered Cavity RF Evaluation and Testing, Second TM211 mode
COMSOL® analysis indicates that there are two TM211 modes within a couple of MHz of one another for the as-built tapered thruster. The higher frequency TM211 mode has a much higher predicted quality factor (32,125), but considerably lower thrust to power performance (5 micronewtons per watt). The tapered RF system was tuned and operated at this mode for evaluation on the low thrust torsion pendulum. The measured quality factor was 18,100 with a power-forward/power-reflected difference of 16.74 watts and the average measured thrust was 50.1 micronewtons. With an input power of 16.74 watts, correcting for the quality factor, the predicted thrust was 47 micronewtons.>>

Unfortunately, the NASA report only shows the frequencies, but it does not show the mode shapes.  One cannot tell why a frequency of only  a couple of MHz higher has a Q more than 4 times higher but a thrust force half as much as the lower frequency.  It would be nice to have a picture of the mode actual mode shapes (as shown in the reference submitted by Mulletron http://www.gregegan.net/SCIENCE/Cavity/Cavity.html for a different geometry) to tell what is the difference in the mode shapes: what gets excited in the cavity that makes such a big difference.

Or is the thrust force (twice higher) at the 2 MHz lower frequency not really due to the mode shape but is it due to something happening in the dielectric resonator and/or coupling with something (dark matter for example)?

COMSOL® field plot for 1932.6 MHz, TM211 also shown for reference - red is electric, blue is magnetic

I'm looking at pg 18 of the paper, with the results you posted, I remember when I picked the paper apart, my takeaway was that the TE012 mode was very efficient, with 2.6 watts in and 55uN peak and average thrust out. The Q factor didn't matter much. Comparing the TM211 mode, higher Q killed thrust. Why so few test runs anyway? Here's some stuff I wrote down on the Nasa report using info that I got from Navy Neets Module 11 and sources on the internet. So take TE012, or TExyz. X is the # of 1/2 wavelengths across a half circumference, y is the # of 1/2 wavelengths across a radius, Z is the poynting vector with the # of 1/2 wavelengths of length of the cavity. I forget of those modes are the big or small end or both if it is in proportion. You can calculate the size of the cavity using the info on page 18. Oh, it also clearly says it don't work without dielectric.

I tried making the same notes on a screenshot of the paper using paint but that failed. I'll take a pic or scan my annotated paper and post it when I get home.
« Last Edit: 10/05/2014 01:32 PM by Mulletron »
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Offline JohnFornaro

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Re: EM Drive Developments
« Reply #1437 on: 10/05/2014 01:25 PM »

http://www.theory.tifr.res.in/~hbar/PDF/ti.pdf

Thanks for this.  Starts making it more clear to me how the "dielectric" fits in to all this.
Sometimes I just flat out don't get it.

Offline JohnFornaro

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Re: EM Drive Developments
« Reply #1438 on: 10/05/2014 01:26 PM »

You know, before we blame [anyone] for bringing [another] theory here...

You totally miss the point, young Paduan.  There is no "blame" for bringing up various theories.
Sometimes I just flat out don't get it.

Offline JohnFornaro

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Re: EM Drive Developments
« Reply #1439 on: 10/05/2014 01:26 PM »
Propeller/slow wind : power of the device is used to accelerate DM particles.

I would like to read more about this approach.
« Last Edit: 10/05/2014 01:26 PM by JohnFornaro »
Sometimes I just flat out don't get it.

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