Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1798271 times)

Online Rodal

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We are using the same definition of open system :)

I do think Shawyer  attempted to "open" the cavity by invoking Special Relativity (incorrectly). White uses the QV (almost in an extra dimensional way) to open the system. Yang appears to make no attempt at doing so and thus the reason for my question.

Going extra dimensional, 4+1, also opens up the cavity. However, in looking over Randall/Sundrum I realized that their +1 is not on our D-Brane and is rather the bulk itself.  According to string theory this means RF energy can not enter the +1 dimension,yet  in the same breath Randall wonders if Standard Model particles are in the bulk.  Of course there is the possibility of other dimensions outside of their theory.

I am hoping that given Yang's substantially higher thrust that the manner in which the cavity is opened up could be discerned helping theory move forward.

A perfectly reasonable argument for calling it an open system is to acknowledge that vacuum fluctuations of the electromagnetic field are common to both inside and outside the cavity. They are everywhere.

That just flipped on a light bulb! I was thinking about the magnetic gauge potential, vector field. It cannot be shielded by copper or any conductor, and results in the Aharonov-Bohm effect on moving electrons. The Aharonov-Bohm effect is basically a phase shift of the electron wave function, due to its interaction with the gauge field. As I was saying, interference patterns, blah, blah, blah...,

"This is the quantum-mechanical law, which replaces the Lorentz force!" (qv x B) (Felsager - Geometry Particles, and Fields, Ch. 2, sec. 2.6. GREAT book by the way!

In TM01 mode, there is a solenoidal magnetic field, B circulating around the axis of the frustum. In this configuration, the gauge vector field, A is toroidal and coaxial with the frustum, it exits through the copper end plates front and back and is by definition and "open" system.

In TE01 mode however, I think the magnetic field is toroidal inside the frustum, (correct?) trapping the A field inside.  Hmmm.... I know Lorentz forces are what is making it move, so this is relevant. Just haven't decided how yet.  :o

Todd
Both TMmnp and TEmnp modes for a cavity are (at least mathematically) known as solenoidal modes.  All transverse electric modes are solenoidal as well, where by a solenoidal vector field I take the mathematical definition: a vector field with zero divergence.  Also I think that the solenoidal word means being constrained as if in a pipe (a cylindrical shape).  The difference is that in the TM01p modes the magnetic field is in the azimuthal direction while the electric field is in the transverse and axial directions.  For  TE01p modes the electric field is in the azimuthal direction while the magnetic field is in the transverse and axial directions.

Minkowski, in his relativity theory, interpreted magnetic fields as just a relativistic manifestation of the same electromagnetic field responsible for the electric field, and not as something fundamentally different. Also, in a cavity the energy density can be expressed just in terms of the electric field or the magnetic field because when one is maximum the other one is zero, so the energy goes from one field to the other field. The energy goes from the TM mode to the TE mode, back and forth.  So, if you consider the system to be open for one mode, you should consider it open for the other mode as well, since the energy goes from one mode to the other mode.

There are also irrotational solutions for Maxwell's equations that satisfy the boundary conditions for a resonant cavity.  Greg Egan considered only the solenoidal fields.  Egan did not consider the irrotational solutions because they are static fields.  Egan just considered the time-varying electromagnetic fields.

« Last Edit: 06/04/2015 01:57 PM by Rodal »

Offline CW

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Hello Todd - it's me, the thorn in your side.
Quote
It is my experience and opinion that "curved space time" and "variable refractive index" are two interpretations of the same phenomenon. You can't say one is correct and the other is not, just because the opinion of main stream physicists "prefer" GR over PV. You are entitled to your own opinion however, please don't discredit me for having one of my own.
But I can disagree with your opinion. So I shall.

In a curved space time, a photon travels its geodesic at c.
In a medium with a non-unity refractive index n, a photon is involved with continual interactions with atoms and molecules, and is continually absorbed and re-emitted, and part of the time it is expressed as a phonon or a polariton etc. Whenever it is actualised, which is part of the time, it travels at the vacuum value of c.  As a result of this messy collection of processes, it appears as though the photon is travelling at c/n along its straight refracted path.

These two scenarios are not equivalent at all.

I fully agree. If you look at atoms as little absorbers/emitters of photons and consider the fact that there is a temporal distribution of when exactly an absorbed photon will be emitted again, it's easy to liken a crystal lattice to an electronic shift register. A photon gets absorbed by one of the 'bits', stored for some time and then a new photon is emitted to a neighboring 'bit'. A photon always and invariably travels with lightspeed c = ~300'000km/s between 'bits'. From the outside, it looks like an effectively slowed down movement of photons through a material. But that's not changing light speed itself.. . I hope that much is obvious.
:)
Reality is weirder than fiction

Offline WarpTech

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To equate the smooth motion of a photon along a curved geodesic to the jumpy progress of a photon in a medium seems a stretch to me.

So to indulge this idea a little more: refractive index in the real world is a complex number, as are relative permeability and permittivity. What equivalent complex number describes gravity? What does the imaginary part mean? What is "imaginary gravity"?

How about this instead;

G^uv = 8pi*G*T^uv, where T^uv = Stress-Energy Tensor of the EM field ONLY.

EM energy creates gravity and a metric. Therefore EM fields can also create a refractive index such that "light can bend light". Nice and smooth!

Regarding gravity in my QFT. The "Reactive" power is stored in matter as charged oscillators at resonance. The "Real"  power is the attenuation of the particle resonators that makes them "fall", which results from the Radiation Reaction damping force, from the superposition of all matter & fields. Dead Simple actually...  ;D

"Imaginary gravity" IMO is; Empty space with nothing in it, but it's "curved", LOL! 8) You need to have quite an imagination to accept that.

Todd
« Last Edit: 06/04/2015 02:11 PM by WarpTech »

Offline deltaMass

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To equate the smooth motion of a photon along a curved geodesic to the jumpy progress of a photon in a medium seems a stretch to me.

So to indulge this idea a little more: refractive index in the real world is a complex number, as are relative permeability and permittivity. What equivalent complex number describes gravity? What does the imaginary part mean? What is "imaginary gravity"?

How about this instead;

G^uv = 8pi*G*T^uv, where T^uv = Stress-Energy Tensor of the EM field ONLY.

EM energy creates gravity and a metric. Therefore EM fields can also create a refractive index such that "light can bend light". Nice a smooth!

Regarding gravity in my QFT. The "Reactive" power is stored in matter as charged oscillators at resonance. The "Real"  power is the attenuation of the particle resonators that makes them "fall", which results from the Radiation Reaction damping force, from the superposition of all matter & fields. Dead Simple actually...  ;D

"Imaginary gravity" IMO is; Empty space with nothing in it, but it's "curved", LOL! 8) You need to have quite an imagination to accept that.

Todd
"Therefore EM fields can also create a refractive index". That's a funny way of describing the situation - normally we think of a medium acting on the field rather than the other way around. Be that as it may, it seems that this "refractive index" concoction does indeed have both real and imaginary parts. In ordinary refraction, it is the imaginary part that represents loss/dissipation. It seems that with this version, the real and imaginary components are swapped around, with your real part being the lossy one.

Or do I misunderstand?

Offline wallofwolfstreet

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Please notice that the first worldwide replication test by a "Do it yourself", by Iulian Berca (in Romania), had a measured thrust force that when calculated as an average of runs in tests 3 and 3.1, subtracting out the likely "gas effect", as per @deltaMass calculated net thrust of 0.29gf effective thrust, which is 2.84mN, according to the EM Drive wiki page:  http://emdrive.wiki/Experimental_Results

...


That is an overly optimistic analysis of Iulian's experiment.   He did 3 tests.   The first, which attempted to observe a horizontal deflection, was null.   Test 3.0 (are there other tests that haven't been reported?  That sounds familiar) attempted to measure an upward force on the cavity.   His one measurement from that experiment was 0.508 gram force.   If that force was entirely from the RF energy and not from air heating inside the cavity one would expect the first test to show a deflection since he did say that approximately a gram force was necessary to cause an observable horizontal deflection.     Experiment 3.1 was a 180 change in orientation.   Again, if the force was entirely from the RF energy one would expect an equal but opposite force.    The fact that the measured force in the downward direction was 7X smaller nullifies both experiments.    Another experiment that could be done would be to stick a lighted match inside the cavity and measure the "thrust" that produces.

This is not a criticism of Iulian.   I think he showed a lot of ingenuity and craftsmanship.  And if he has decided to move on to other projects, so much the better.

I noticed that somebody put Iulian's test in the wiki http://emdrive.wiki/Experimental_Results with this message, quoting DeltaMass:

Quote
Because of the high profile nature of the tests, they are included here merely to give a rough comparison to the more scientifically rigorous tests. The measured thrust in this table is an average of multiple runs in tests 3 and 3.1, subtracting out the likely effects of hot air. @deltaMass calculated the net thrust for the EmDrive across both tests to be 0.29gf effective thrust, which is 2.84mN. 

Which gives a thrust/InputPower similar to the one measured by NASA.

On the basis of your comment above, do you think that Iulian's test should be taken out of the comparison table?

Or, if you think that  Iulian's test should remain in the comparison table, what numbers would you suggest to put in the table instead of the numbers in the table?

I really admire what Iulian did, but I personally wouldn't feel confident enough in the result to keep it in the table.  Without making a comment on the experimental setup, I have a single criticism that, to me, would be enough to omit the results until further work is done:

When employing the equation to normalize out the force of buoyancy, namely (Tup-Tdown)/2, there is a rather massive assumption that is, of yet, unfounded; that there is in fact emdrive thrust.  In order to employ the above equation, you must first assume that the only two forces acting on the frustum are the force of buoyancy and this mysterious thrust force.  But the purpose of Iulian's test was to determine if there was or wasn't any thrust, correct?

If proving thrust requires that you must first assume thrust exists, then of course you can prove thrust, by definition

How can we rule out any myriad of other forces that would have acted upon the cavity and played into the above equation?

I've done enough experiments (many of them in cellular biology, which is notorious for a lack of reproducibility) to confidently state that experimenting is hard.  It can be tempting to take a trial run or two, throw an equation or a statistical method at it and report a result.  This can get you in real trouble, real quickly.  So while I admire what Iulian is doing, I think we need to be realistic.           

Offline deltaMass

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Regarding the Wiki with my calculation of Iulian's force, I described it in a post here. The quoted verbiage above does not belong to me. I simply took the forward and reverse thrusts and accounted for a mass 'a' of air loss due to heating, assuming it was the same for both orientations. Same with the thrust 'T'. Thus
T + a = |F1|
-T + a = |F2|
where F1, F2 are the measured weight changes. These 2 equations were solved for T and a.

It's necessary to do this because it turns out that T,a are of the same order of magnitude. Accounting for 'a' explains the seemingly odd difference in the two weight changes for the two orientations. In other words, it would be a mistake not to account for air mass loss.
« Last Edit: 06/04/2015 02:19 PM by deltaMass »

Offline rfmwguy

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Please notice that the first worldwide replication test by a "Do it yourself", by Iulian Berca (in Romania), had a measured thrust force that when calculated as an average of runs in tests 3 and 3.1, subtracting out the likely "gas effect", as per @deltaMass calculated net thrust of 0.29gf effective thrust, which is 2.84mN, according to the EM Drive wiki page:  http://emdrive.wiki/Experimental_Results

...


That is an overly optimistic analysis of Iulian's experiment.   He did 3 tests.   The first, which attempted to observe a horizontal deflection, was null.   Test 3.0 (are there other tests that haven't been reported?  That sounds familiar) attempted to measure an upward force on the cavity.   His one measurement from that experiment was 0.508 gram force.   If that force was entirely from the RF energy and not from air heating inside the cavity one would expect the first test to show a deflection since he did say that approximately a gram force was necessary to cause an observable horizontal deflection.     Experiment 3.1 was a 180 change in orientation.   Again, if the force was entirely from the RF energy one would expect an equal but opposite force.    The fact that the measured force in the downward direction was 7X smaller nullifies both experiments.    Another experiment that could be done would be to stick a lighted match inside the cavity and measure the "thrust" that produces.

This is not a criticism of Iulian.   I think he showed a lot of ingenuity and craftsmanship.  And if he has decided to move on to other projects, so much the better.

I noticed that somebody put Iulian's test in the wiki http://emdrive.wiki/Experimental_Results with this message, quoting DeltaMass:

Quote
Because of the high profile nature of the tests, they are included here merely to give a rough comparison to the more scientifically rigorous tests. The measured thrust in this table is an average of multiple runs in tests 3 and 3.1, subtracting out the likely effects of hot air. @deltaMass calculated the net thrust for the EmDrive across both tests to be 0.29gf effective thrust, which is 2.84mN. 

Which gives a thrust/InputPower similar to the one measured by NASA.

On the basis of your comment above, do you think that Iulian's test should be taken out of the comparison table?

Or, if you think that  Iulian's test should remain in the comparison table, what numbers would you suggest to put in the table instead of the numbers in the table?

I really admire what Iulian did, but I personally wouldn't feel confident enough in the result to keep it in the table.  Without making a comment on the experimental setup, I have a single criticism that, to me, would be enough to omit the results until further work is done:

When employing the equation to normalize out the force of buoyancy, namely (Tup-Tdown)/2, there is a rather massive assumption that is, of yet, unfounded; that there is in fact emdrive thrust.  In order to employ the above equation, you must first assume that the only two forces acting on the frustum are the force of buoyancy and this mysterious thrust force.  But the purpose of Iulian's test was to determine if there was or wasn't any thrust, correct?

If proving thrust requires that you must first assume thrust exists, then of course you can prove thrust, by definition

How can we rule out any myriad of other forces that would have acted upon the cavity and played into the above equation?

I've done enough experiments (many of them in cellular biology, which is notorious for a lack of reproducibility) to confidently state that experimenting is hard.  It can be tempting to take a trial run or two, throw an equation or a statistical method at it and report a result.  This can get you in real trouble, real quickly.  So while I admire what Iulian is doing, I think we need to be realistic.           

2 cents, I would leave Iulians data there, especially at this early stage. As Shell said, we need Data, Data, Data and this is better that waiting for prior test beds to cough up more Data. To me its an "inspiration factor" that we really need to keep out there.

Offline deltaMass

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This is my final attempt with Iulian's data, posted to YouTube. The one posted above is cruder. Here I make a rudimentary attempt to deduce error bars.

The readings are fairly unstable and sometimes the "tared zero" at test start is not actually indicating zero. Also, air convection out of the cavity must be allowed to occur before a reading is taken. Bearing these points in mind, I put some limits on the indicated values for the 3.0 (thrust up) and 3.1 (thrust down) tests by carefully watching the videos. Roughly I found

Up:     0.80 -> 1.15  or 0.28 -> 0.40 gm-wt
Down: 0.16 -> 0.24  or 0.05 -> 0.08 gm-wt

from which we can deduce that
Thrust    = (Up + Down)/2 = 0.16 -> 0.30 = 0.23 +/-0.07 gm-wt
DeltaAir = (Up - Down)/2  = 0.11 -> 0.21  = 0.16 +/-0.05 gm-wt

You can see that there's no point going beyond 2 decimal points of accuracy.
« Last Edit: 06/04/2015 02:32 PM by deltaMass »

Offline WarpTech

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To equate the smooth motion of a photon along a curved geodesic to the jumpy progress of a photon in a medium seems a stretch to me.

So to indulge this idea a little more: refractive index in the real world is a complex number, as are relative permeability and permittivity. What equivalent complex number describes gravity? What does the imaginary part mean? What is "imaginary gravity"?

How about this instead;

G^uv = 8pi*G*T^uv, where T^uv = Stress-Energy Tensor of the EM field ONLY.

EM energy creates gravity and a metric. Therefore EM fields can also create a refractive index such that "light can bend light". Nice a smooth!

Regarding gravity in my QFT. The "Reactive" power is stored in matter as charged oscillators at resonance. The "Real"  power is the attenuation of the particle resonators that makes them "fall", which results from the Radiation Reaction damping force, from the superposition of all matter & fields. Dead Simple actually...  ;D

"Imaginary gravity" IMO is; Empty space with nothing in it, but it's "curved", LOL! 8) You need to have quite an imagination to accept that.

Todd
"Therefore EM fields can also create a refractive index". That's a funny way of describing the situation - normally we think of a medium acting on the field rather than the other way around. Be that as it may, it seems that this "refractive index" concoction does indeed have both real and imaginary parts. In ordinary refraction, it is the imaginary part that represents loss/dissipation. It seems that with this version, the real and imaginary components are swapped around, with your real part being the lossy one.

Or do I misunderstand?

I think we have them swapped because you are referring to the real and imaginary parts of the refractive index and I'm referring to the real and imaginary parts of the Power. The real part of the index results in stored energy and reactive "Imaginary" power, where the imaginary part of the refractive index results in attenuation and "Real" power. In any case, the refractive index results from constructive and destructive interference, and if you really think about it, particles are also waves and it is the same process that affects particles. You can think of it as photons absorbed and emitted as particles, but you can also show the same thing as a superposition of waves.
« Last Edit: 06/04/2015 02:39 PM by WarpTech »

Offline rfmwguy

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...   
2 cents, I would leave Iulians data there, especially at this early stage. As Shell said, we need Data, Data, Data and this is better that waiting for prior test beds to cough up more Data. To me its an "inspiration factor" that we really need to keep out there.
Thanks for the clarification.  Since you "liked" wallofwolfstreet post saying that Iulian's data should be taken out of the table, I thought you agreed with wallofwolfstreet that it should be taken out.  Now I understand that you are in favor of leaving the present numbers.

Yes, I liked his post...well stated position without rudeness...didn't agree, but thought he presented his position well. (I tend to like anyone's posts that rise above the typical hand-waving blog antics)  :D

Offline deltaMass

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This is my final attempt with Iulian's data, posted to YouTube. The one posted above is cruder. Here I make a rudimentary attempt to deduce error bars.

The readings are fairly unstable and sometimes the "tared zero" at test start is not actually indicating zero. Also, air convection out of the cavity must be allowed to occur before a reading is taken. Bearing these points in mind, I put some limits on the indicated values for the 3.0 (thrust up) and 3.1 (thrust down) tests by carefully watching the videos. Roughly I found

Up:     0.80 -> 1.15  or 0.28 -> 0.40 gm-wt
Down: 0.16 -> 0.24  or 0.05 -> 0.08 gm-wt

from which we can deduce that
Thrust    = (Up + Down)/2 = 0.16 -> 0.30 = 0.23 +/-0.07 gm-wt
DeltaAir = (Up - Down)/2  = 0.11 -> 0.21  = 0.16 +/-0.05 gm-wt

You can see that there's no point going beyond 2 decimal points of accuracy.
So, are you in favor of not having Iulian's data in the table? Or, if you are in favor, what number [please choose #digits] for force (in milliNewtons,  1 gram force  = 9.80665 milliNewtons) would you put in the table for thrust? Are you in favor of placing 0.23gf= 2.3 mN  in the table?

The numbers now, posted by:

06:56, 1 June 2015‎ Sfrank (Talk | contribs)‎ . . (4,925 bytes) (+769)‎ . . (Added Iulian tests 3/3.1 with caveat that thrust and input are extremely approximate. Will create a page dedicated to his tests to explain results in detaiil.) (undo)

came from your previous post showing,  instead:
T = 0.290 gm-wt (thrust forward from small end)
I favour the latter post because I took cognizance of the sloppy taring and the multiple weighing attempts. Therefore

T = 2.26 +/-0.69 mN

EDIT I think more honest would be to drop a digit, as you suggest:

T = 2.3 +/-0.7 mN
« Last Edit: 06/04/2015 02:56 PM by deltaMass »

Online Rodal

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...
I favour the latter post because I took cognizance of the sloppy taring and the multiple weighing attempts. Therefore

T = 2.26 +/-0.69 mN

EDIT I think more honest would be to drop a digit, as you suggest:

T = 2.3 +/-0.7 mN

Fine, that doesn't change the  original argument.  Actually, the measured Force/PowerInput for Iulian Berca is now even closer to NASA's Brady b.

The force measured by Iulian is about 44 times smaller than the force reported by Shawyer  for the Demonstrator.

As to the argument:

Quote
If proving thrust requires that you must first assume thrust exists, then of course you can prove thrust, by definition

that can be said about all the experimental measurements in the table (admittedly, to different degrees, nobody expects the tests from Iulian to have the same accuracy as the ones at NASA).

Who is to say that ALL experimental measurements are not experimental artifacts?  As far as I am concerned the table just shows reported forces.  Interpretations and arguments about whether the reported forces are "thrust" are unwarranted at this point in time, and lead to circular arguments, just like arguing about whether the EM Drive will take you to the stars or give you free energy, when right now the reported forces are very small and the measurements have taken place over small periods of time, and there is no accepted theoretical explanation as to how it could be producing "thrust".
« Last Edit: 06/04/2015 03:32 PM by Rodal »

Offline zen-in

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...

The choice here is either not to include the experiments by Iulian (if you think that his tests self-nullify each other, and therefore you think that you cannot put any  numbers in the common format) or, if to include them, to put a number for the experiments.  @aero wrote, that Iulian's experiments should remain in the table.  In that case, if you think that the quoted numbers from deltaMass are incorrect and misrepresent the true tests, what numbers for Iulian tests would you suggest to put in the table under the agreed format?

I don't believe any of the "results" listed in the table are valid thrust measurements.   None of the experiments have been done with controls to eliminate thermal effects, spurious magnetic interactions, torque from fluid pumping, etc, etc.    And the data presented in that table represents cherry-picked data where an unknown number of failed experiments have been quietly ignored.    On that basis if I were to say that Iulian's experiments should not be listed I would have to say it for all the others as well. 

Offline wallofwolfstreet

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This is my final attempt with Iulian's data, posted to YouTube. The one posted above is cruder. Here I make a rudimentary attempt to deduce error bars.

The readings are fairly unstable and sometimes the "tared zero" at test start is not actually indicating zero. Also, air convection out of the cavity must be allowed to occur before a reading is taken. Bearing these points in mind, I put some limits on the indicated values for the 3.0 (thrust up) and 3.1 (thrust down) tests by carefully watching the videos. Roughly I found

Up:     0.80 -> 1.15  or 0.28 -> 0.40 gm-wt
Down: 0.16 -> 0.24  or 0.05 -> 0.08 gm-wt

from which we can deduce that
Thrust    = (Up + Down)/2 = 0.16 -> 0.30 = 0.23 +/-0.07 gm-wt
DeltaAir = (Up - Down)/2  = 0.11 -> 0.21  = 0.16 +/-0.05 gm-wt

You can see that there's no point going beyond 2 decimal points of accuracy.

Appreciate the work you're doing getting this data more accessible, but maybe I could take this opportunity to just further flesh out what I was getting at with my previous post:

Do you feel that the only two (significant) forces acting on the frustum in Iulian's experiment are buoyancy (DeltaAir) and thrust?

What about:
Material ablation/ejection
Thermal convection outside of the cavity from heated walls
The force of the spring on Iulian's torque arm
Accumulating errors in the digital scale from rf exposure
Thermal buckling causing a shift in the COM
Forces between wires connected to the frustum and wires that are not
etc. 

If these effects are on the same order of magnitude as thrust and DeltaAir, then the above equations don't actually apply, and we are unable to conclude any thrust, much less accurately calculate it.

Not trying to be a negative Nancy, just a skeptical Sammy.  After all, if you go into the darker part of youtube, you can find literally hundreds of videos of free-energy machines, all apparently working without issue.  Many, if not most of these, are not scams or hoaxes, but earnest experiments that just failed to account for all the confounding factors.

Offline deltaMass

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This is my final attempt with Iulian's data, posted to YouTube. The one posted above is cruder. Here I make a rudimentary attempt to deduce error bars.

The readings are fairly unstable and sometimes the "tared zero" at test start is not actually indicating zero. Also, air convection out of the cavity must be allowed to occur before a reading is taken. Bearing these points in mind, I put some limits on the indicated values for the 3.0 (thrust up) and 3.1 (thrust down) tests by carefully watching the videos. Roughly I found

Up:     0.80 -> 1.15  or 0.28 -> 0.40 gm-wt
Down: 0.16 -> 0.24  or 0.05 -> 0.08 gm-wt

from which we can deduce that
Thrust    = (Up + Down)/2 = 0.16 -> 0.30 = 0.23 +/-0.07 gm-wt
DeltaAir = (Up - Down)/2  = 0.11 -> 0.21  = 0.16 +/-0.05 gm-wt

You can see that there's no point going beyond 2 decimal points of accuracy.

Appreciate the work you're doing getting this data more accessible, but maybe I could take this opportunity to just further flesh out what I was getting at with my previous post:

Do you feel that the only two (significant) forces acting on the frustum in Iulian's experiment are buoyancy (DeltaAir) and thrust?

What about:
Material ablation/ejection
Thermal convection outside of the cavity from heated walls
The force of the spring on Iulian's torque arm
Accumulating errors in the digital scale from rf exposure
Thermal buckling causing a shift in the COM
Forces between wires connected to the frustum and wires that are not
etc. 

If these effects are on the same order of magnitude as thrust and DeltaAir, then the above equations don't actually apply, and we are unable to conclude any thrust, much less accurately calculate it.

Not trying to be a negative Nancy, just a skeptical Sammy.  After all, if you go into the darker part of youtube, you can find literally hundreds of videos of free-energy machines, all apparently working without issue.  Many, if not most of these, are not scams or hoaxes, but earnest experiments that just failed to account for all the confounding factors.
Thanks, and I totally agree. Having precalculated the order of magnitude of the expected weight loss due to expelled air, and finding it comparable in magnitude to the reported weight changes he was seeing, I felt it had to be included. Indeed, without including it, the inverted weight change would be pretty much unexplainable using only thrust as a model.

But point taken. These experiments vary in their professionalism, and your list is very germane. This is why I keep harking on about a totally enclosed system being the best way.
« Last Edit: 06/04/2015 03:15 PM by deltaMass »

Offline Flyby

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This is my final attempt with Iulian's data, posted to YouTube. The one posted above is cruder. Here I make a rudimentary attempt to deduce error bars.

The readings are fairly unstable and sometimes the "tared zero" at test start is not actually indicating zero. Also, air convection out of the cavity must be allowed to occur before a reading is taken. Bearing these points in mind, I put some limits on the indicated values for the 3.0 (thrust up) and 3.1 (thrust down) tests by carefully watching the videos. Roughly I found

Up:     0.80 -> 1.15  or 0.28 -> 0.40 gm-wt
Down: 0.16 -> 0.24  or 0.05 -> 0.08 gm-wt

from which we can deduce that
Thrust    = (Up + Down)/2 = 0.16 -> 0.30 = 0.23 +/-0.07 gm-wt
DeltaAir = (Up - Down)/2  = 0.11 -> 0.21  = 0.16 +/-0.05 gm-wt

You can see that there's no point going beyond 2 decimal points of accuracy.

It has been mentioned before, but you forgot to include the spring tension working against the "thrust" force when the frustum small-end was down, and working with it when it was pointing upwards.

I'm not sure what the characteristics were of that spring, but they're usually progressive and not linear, meaning the absolute force to pull it down is greater then the absolute force to pull it up. So, although the spring forces are leveled out by gravity itself, there is a spring force delta between the forces up or down
due to the material resistance.

It means that the down force thrust (if we may call it like that) had a bigger counteracting force, so the supposedly thrust force will be greater then what you mentioned.
At the same time, the upward force thrust had some extra help, making it bigger then what it actually was.
With that difference that the extra help of the spring is a bit smaller then the spring stretching force, so that they do not entirely cancel each other out, and put the downward force in a disadvantage...

If you see the need to mention the delta_air, then it surely makes sense to include the spring forces as well. Problem there is that we do not know their force contribution or the springs properties... sadly.

I see Iullian's experiment as an potential indication, but the lack of data and accuracy prohibit to see it as evidence... It is an experiment that gives hope or promise, not proof...

EUhh.. nevermind, I see someone had already brought that up while typing... :)
« Last Edit: 06/04/2015 03:24 PM by Flyby »

Offline phaseshift

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A perfectly reasonable argument for calling it an open system is to acknowledge that vacuum fluctuations of the electromagnetic field are common to both inside and outside the cavity. They are everywhere.

Agreed.  In addition I can think of a few other ways that the system could be open and I'm sure there are others. I was putting this list together on my walk yesterday morning

1. Earth's, Sun's, Galaxy's electromagnetic field,
2. Earth's, Sun's, Galaxy's gravitational field,
3. Unruh radiation,
4. Neutrinos, (doubtful)
5. Higgs Fields,
6. Quantum Vacuum,
7. 3 + Nth spatial dimension,
8. 3 + Nth spatial dimension + Plank Brane,
9. Quantum Tunneling (though this is unlikely due to thickness of the copper)
10. Others?

I would like to add to, and cross off of, this list :)
« Last Edit: 06/04/2015 03:41 PM by phaseshift »
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Offline WarpTech

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That just flipped on a light bulb! I was thinking about the magnetic gauge potential, vector field. It cannot be shielded by copper or any conductor, and results in the Aharonov-Bohm effect on moving electrons. The Aharonov-Bohm effect is basically a phase shift of the electron wave function, due to its interaction with the gauge field. As I was saying, interference patterns, blah, blah, blah...,

"This is the quantum-mechanical law, which replaces the Lorentz force!" (qv x B) (Felsager - Geometry Particles, and Fields, Ch. 2, sec. 2.6. GREAT book by the way!

In TM01 mode, there is a solenoidal magnetic field, B circulating around the axis of the frustum. In this configuration, the gauge vector field, A is toroidal and coaxial with the frustum, it exits through the copper end plates front and back and is by definition and "open" system.

In TE01 mode however, I think the magnetic field is toroidal inside the frustum, (correct?) trapping the A field inside.  Hmmm.... I know Lorentz forces are what is making it move, so this is relevant. Just haven't decided how yet.  :o

Todd
Both TMmnp and TEmnp modes for a cavity are (at least mathematically) known as solenoidal modes.  All transverse electric modes are solenoidal as well, where by a solenoidal vector field I take the mathematical definition: a vector field with zero divergence.  Also I think that the solenoidal word means being constrained as if in a pipe (a cylindrical shape).  The difference is that in the TM01p modes the magnetic field is in the azimuthal direction while the electric field is in the transverse and axial directions.  For  TE01p modes the electric field is in the azimuthal direction while the magnetic field is in the transverse and axial directions.

Minkowski, in his relativity theory, interpreted magnetic fields as just a relativistic manifestation of the same electromagnetic field responsible for the electric field, and not as something fundamentally different. Also, in a cavity the energy density can be expressed just in terms of the electric field or the magnetic field because when one is maximum the other one is zero, so the energy goes from one field to the other field. The energy goes from the TM mode to the TE mode, back and forth.  So, if you consider the system to be open for one mode, you should consider it open for the other mode as well, since the energy goes from one mode to the other mode.

There are also irrotational solutions for Maxwell's equations that satisfy the boundary conditions for a resonant cavity.  Greg Egan considered only the solenoidal fields.  Egan did not consider the irrotational solutions because they are static fields.  Egan just considered the time-varying electromagnetic fields.

I tried to define what I meant by solenoidal: circulating around the axis of the frustum The Maxwell Field has 4 potentials, A^u=(phi, A), u = 0,1,2,3,  "A" is parallel to the axis of the frustum. I understand solenoidal refers to any vector field that does not have divergence, but I was trying to describe the field wrapping around the axis, not a torroidal "B" field wrapping around the minor circumference. In QFT, the best example is a superconductor, where "phi" simply represents the scalar phase of the field.

I understand oscillating from TE to TM, I'm just thinking out loud and you're correct it applies in both modes.  A^u exists on both sides of the conductors, regardless of the mode.

Todd

Offline phaseshift

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What about:
Material ablation/ejection
Thermal convection outside of the cavity from heated walls
The force of the spring on Iulian's torque arm
Accumulating errors in the digital scale from rf exposure
Thermal buckling causing a shift in the COM
Forces between wires connected to the frustum and wires that are not
etc. 


I would like to see a comprehensive enumeration of every experimental artifact that should be compensated/accounted for and get it on the wiki or some place that the experimenters have immediate access to.

The emdrive wiki has a rudimentary list - can we work to flesh it out? :)
« Last Edit: 06/04/2015 04:54 PM by phaseshift »
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Offline Star One

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What about:
Material ablation/ejection
Thermal convection outside of the cavity from heated walls
The force of the spring on Iulian's torque arm
Accumulating errors in the digital scale from rf exposure
Thermal buckling causing a shift in the COM
Forces between wires connected to the frustum and wires that are not
etc. 


I would like to see a comprehensive enumeration of every experimental artifact that should be compensated for and get it on the wiki or some place that the experimenters have immediate access to.

Some of these I would have thought would be eliminated by more power, so that if there is any thrust it becomes more apparent above the background noise. Surely this is one of the reasons that EW are looking to develop a higher powered experiment.

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