Author Topic: EM Drive Developments - related to space flight applications - Thread 10  (Read 341987 times)

Online Rodal

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Notice: not proportional to the square of the inverse -like Newtonian gravitational forces-, but proportional to the inverse.   Thus the decay with distance is much smaller than the decay of Newtonian gravitational forces.  On the other hand the dimensionless strain amplitude is proportional to the second derivative of the mass distribution of the source and inversely proportional to the distance from the source.
Slightly irrelevant question. Is this the amplitude of the wave that decreases inversely with distance? (i.e. physical length change as measured by a gravitational wave detector)

In waves such as electromagnetic waves, energy and momentum density are proportional to the square of the field strength. This means that while the energy per unit area (power per area if you are talking continuous and not short burst) in the wave decreases with the square of the distance, the field strength would only decrease linearly. I'd expect similar statements to be true for gravitational waves.
Actually a relevant question.

I was talking about the non-dimensional strain (h in perturbation theory) as a measure of the amplitude effect of the gravitational wave

Quote
The relative length change of two points resulting from gravitational wave is expressed as

Max stretching & shrinking = hL,

where L is a distance between two points and h is the dimensionless strain amplitude which is proportional to the second derivative of the mass distribution of the source and inversely proportional to the distance from the source.

The strain between two points is the most commonly accepted way to discuss such magnitude.


See:  http://web.mit.edu/klmitch/classes/8.224/project/gravwave.html

« Last Edit: 09/13/2017 08:49 PM by Rodal »

Online meberbs

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Thanks. This is what I thought you meant, but I wanted to be sure. That site also confirms that the energy proportional to square of amplitude applies to gravitational waves just as it does to EM waves.

Considering available detection methods, it makes sense that amplitude would be used to discuss gravitational waves while power density is frequently used for EM waves.

Quote
Furthermore, the radiation energy is proportional to the square of the amplitude of the associated gravitational wave

« Last Edit: 09/13/2017 04:28 PM by meberbs »

Online Rodal

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Thanks. This is what I thought you meant, but I wanted to be sure. That site also confirms that the energy proportional to square of amplitude applies to gravitational waves just as it does to EM waves.

Quote
Furthermore, the radiation energy is proportional to the square of the amplitude of the associated gravitational wave

Also of interest:

The luminosity (the total amount of energy emitted by the astronomical objects per unit time) of the gravitational wave from a binary is approximately proportional to mass to the third power M3 and inversely proportional to orbital separation -between the binary objects- as R5

see page 2 of

https://www.astro.umd.edu/~miller/teaching/astr498/lecture25.pdf

and the total energy of a circular binary of radius R is proportional to the mass and inversely proportional to the orbital separation R

When it comes to gravitational waves, mass matters ! [pun intended]    ;)
« Last Edit: 09/13/2017 04:56 PM by Rodal »

Online Bob Woods

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Let me explain a little about why I asked about gravitational wave/spacetime ripples.

I keep thinking about bosons as being force carriers and the resonant electromagnetic fields being created within the frustum. And as someone who forgot most of what I learned almost 50 years ago I know I'm woefully ignorant.

If bosons are electromagnetic "ghosts" that can induce particles to suddenly pop into material existence with mass, and which then disappear again back to an electromagnetic state, then the appearance of mass would move space-time ever slightly (telling it how to curve) thereby transferring momentum. It seems intuitive that the transfer of momentum from a created inertial mass might also be what causes the very tiny mass to dissipate and return to electromagnetism.

Any fleeting particle created that has true mass is unlike a photon. As a result productions of bosons might be a mechanism for creating momentum from transient mass that would exceed the proverbial photon rocket, wouldn't it?

If bosons/particles were produced, it would seem intuitive that it would occur in the regions of the highest energy density, nominally the small end in most of the meep runs shown here. Again, if bosons/particles occur, might their generated infinitesimal momentum transfer also potentially help push the injected energy towards the large end, creating the imbalance that might account for the thrust.  If that thrust does exist.

(Old guy up late last night thinking, and time today to write it down.)[/size]

Offline graybeardsyseng

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Thanks. This is what I thought you meant, but I wanted to be sure. That site also confirms that the energy proportional to square of amplitude applies to gravitational waves just as it does to EM waves.

Quote
Furthermore, the radiation energy is proportional to the square of the amplitude of the associated gravitational wave

Also of interest:

The luminosity (the total amount of energy emitted by the astronomical objects per unit time) of the gravitational wave from a binary is approximately proportional to mass to the third power M3 and inversely proportional to orbital separation -between the binary objects- as R5

see page 2 of

https://www.astro.umd.edu/~miller/teaching/astr498/lecture25.pdf

and the total energy of a circular binary of radius R is proportional to the mass and inversely proportional to the orbital separation R

When it comes to gravitational waves, mass matters ! [pun intended]    ;)

Dr. Rodal et al

Thanks for an excellent discussion of this topic - gravitational waves-  you together with meberbs, and S. Paulissen and of course further reading of  Mssrs. Thorne, Damour, and Blanchet made this much clearer - I've been thinking over this since about 1976.   The concept of spacetime being quite stiff is a excellent example.

   Is this in any way a gravitational radiation analog to the so-called electromagnetic characteristic impedance of free space i.e. square root of ratio of permeability of free space to permittivity of free space; which has a numerical value of about 376.6 ohms?   In the past I have heard older RF engineers  refer to this as how stiff space was WRT RF propagation.

Thanks,

Herman
"There are TWO kinds of ships; Submarines . . . and Targets"    - GO NAVY

Online Rodal

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...
Dr. Rodal et al

Thanks for an excellent discussion of this topic - gravitational waves-  you together with meberbs, and S. Paulissen and of course further reading of  Mssrs. Thorne, Damour, and Blanchet made this much clearer - I've been thinking over this since about 1976.   The concept of spacetime being quite stiff is a excellent example.

   Is this in any way a gravitational radiation analog to the so-called electromagnetic characteristic impedance of free space i.e. square root of ratio of permeability of free space to permittivity of free space; which has a numerical value of about 376.6 ohms?   In the past I have heard older RF engineers  refer to this as how stiff space was WRT RF propagation.

Thanks, e

Herman
Herman,

Thanks for your feedback and your excellent question.  Unfortunately I have not thought (or more importantly I have not analyzed) this enough to discuss the proposed analogy. 
« Last Edit: 09/13/2017 06:46 PM by Rodal »

Offline TheTraveller

Guys,

This experimental data from Jamie, Monomorphic, clearly shows the "stop accelerating or stop moving then stop generating force" operational characterists of EmDrives.

Here the start of acceleration is delayed as Jamie manually adjust his freq gen to obtain resonant lock. Grey area is when Rf was applied to the EmDrive. Any Lorentz force would have been measured during the entire Rf power on time, yet there is no such force measured.

Then once freq lock was obtained, his EmDrive started to generate an accelerative force and it moved forward. Yes it initially needed some very small vibratory external accelerative force to be applied to initiate the EmDrive self sustained and generated internal accelerative force generation.

Finally it stopped accelerating, moving forward,  when the continually increasing stored back torque in the torsion wire finally equalled the Emdrive generated forward torque.

When it stopped accelerating, the EmDrive dropped out of what Roger calls Motor mode and stopped producing accelerative force.

Then the back torque stored in the torsion wire drove the EmDrive back to it's pre acceleration start position, even though Rf was still applied.

Phil
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Online RotoSequence

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Guys,

This experimental data from Jamie, Monomorphic, clearly shows the "stop accelerating or stop moving then stop generating force" operational characterists of EmDrives.

Here the start of acceleration is delayed as Jamie manually adjust his freq gen to obtain resonant lock. Grey area is when Rf was applied to the EmDrive. Any Lorentz force would have been measured during the entire Rf power on time, yet there is no such force measured.

Then once freq lock was obtained, his EmDrive started to generate an accelerative force and it moved forward. Yes it initially needed some very small vibratory external accelerative force to be applied to initiate the EmDrive self sustained and generated internal accelerative force generation.

Finally it stopped accelerating, moving forward,  when the continually increasing stored back torque in the torsion wire finally equalled the Emdrive generated forward torque.

When it stopped accelerating, the EmDrive dropped out of what Roger calls Motor mode and stopped producing accelerative force.

Then the back torque stored in the torsion wire drove the EmDrive back to it's pre acceleration start position, even though Rf was still applied.

Phil

I've made no secret of my distress over the unsubstantiated claims of thrust to power ratios, but this is one of the ideas that I think is actually credible; it's one of the most consistent anomalies across EM drive experiments.

Online Rodal

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Guys,

This experimental data from Jamie, Monomorphic, clearly shows the "stop accelerating or stop moving then stop generating force" operational characterists of EmDrives.

Here the start of acceleration is delayed as Jamie manually adjust his freq gen to obtain resonant lock. Grey area is when Rf was applied to the EmDrive. Any Lorentz force would have been measured during the entire Rf power on time, yet there is no such force measured.

Then once freq lock was obtained, his EmDrive started to generate an accelerative force and it moved forward. Yes it initially needed some very small vibratory external accelerative force to be applied to initiate the EmDrive self sustained and generated internal accelerative force generation.

Finally it stopped accelerating, moving forward,  when the continually increasing stored back torque in the torsion wire finally equalled the Emdrive generated forward torque.

When it stopped accelerating, the EmDrive dropped out of what Roger calls Motor mode and stopped producing accelerative force.

Then the back torque stored in the torsion wire drove the EmDrive back to it's pre acceleration start position, even though Rf was still applied.

Phil

I've made no secret of my distress over the unsubstantiated claims of thrust to power ratios, but this is one of the ideas that I think is actually credible; it's one of the most consistent anomalies across EM drive experiments.
Which can also be explained by a number of experimental artifacts that include significant time delays: thermal diffusion through the materials involved (an effect which would also be present in vacuum, governed by the density and thermal conductivity of the materials involved) and thermal convection (not present in high vacuum, and governed by the gas density and thermal conductivity as well as any latent heat of vaporization of liquid, for example humid air) being notorious among them.  It has also been discussed that the EM Drive may just be a multipactor artifact, and if so time delays due to random secondary emission velocities and other effects may be involved.

So the clarity of
Quote
clearly shows the "stop accelerating
is in the eye of the beholder and willingness to look for other explanations, unless this is verified by other independent means.
« Last Edit: 09/13/2017 10:04 PM by Rodal »

Online RotoSequence

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I've made no secret of my distress over the unsubstantiated claims of thrust to power ratios, but this is one of the ideas that I think is actually credible; it's one of the most consistent anomalies across EM drive experiments.
Which can also be explained by a number of experimental artifacts that include significant time delays: thermal diffusion through the materials involved (an effect which would also be present in vacuum, governed by the density and thermal conductivity of the materials involved) and thermal convection (not present in high vacuum, and governed by the gas density and thermal conductivity as well as any latent heat of vaporization of liquid, for example humid air) being notorious among them.

So the clarity of
Quote
clearly shows the "stop accelerating
is in the eye of the beholder unless this is verified by other independent means.

It's far from proven, for sure. The better word to use would have been plausible, rather than credible. My bad!

Offline TheTraveller

Guys,

This experimental data from Jamie, Monomorphic, clearly shows the "stop accelerating or stop moving then stop generating force" operational characterists of EmDrives.

Here the start of acceleration is delayed as Jamie manually adjust his freq gen to obtain resonant lock. Grey area is when Rf was applied to the EmDrive. Any Lorentz force would have been measured during the entire Rf power on time, yet there is no such force measured.

Then once freq lock was obtained, his EmDrive started to generate an accelerative force and it moved forward. Yes it initially needed some very small vibratory external accelerative force to be applied to initiate the EmDrive self sustained and generated internal accelerative force generation.

Finally it stopped accelerating, moving forward,  when the continually increasing stored back torque in the torsion wire finally equalled the Emdrive generated forward torque.

When it stopped accelerating, the EmDrive dropped out of what Roger calls Motor mode and stopped producing accelerative force.

Then the back torque stored in the torsion wire drove the EmDrive back to it's pre acceleration start position, even though Rf was still applied.

Phil

I've made no secret of my distress over the unsubstantiated claims of thrust to power ratios, but this is one of the ideas that I think is actually credible; it's one of the most consistent anomalies across EM drive experiments.
Which can also be explained by a number of experimental artifacts that include significant time delays: thermal diffusion through the materials involved (an effect which would also be present in vacuum, governed by the density and thermal conductivity of the materials involved) and thermal convection (not present in high vacuum, and governed by the gas density and thermal conductivity as well as any latent heat of vaporization of liquid, for example humid air) being notorious among them.  It has also been discussed that the EM Drive may just be a multipactor artifact, and if so time delays due to random secondary emission velocities and other effects may be involved.

So the clarity of
Quote
clearly shows the "stop accelerating
is in the eye of the beholder and willingness to look for other explanations, unless this is verified by other independent means.

Jose,

Rf power was 2 watt so not much cavity heating there.

Need to also answer why, with constant Rf power, the positive displace force apparently completely stopped, disappeared, as observed from the stored torque in the torsion wire driving the total accelerated mass backward, through the pre acceleration displacement and then to a somewhat same negative displacement until Jamie's dampers finslly absorbed and thermalised the stored energy in the torsion wire.

I repeat again, this is the characterists of an EmDrive.

What EW observed, with constant, non accelerating static force is NOT characterist of an EmDrive. It maybe was the characterist of the QV thruster Dr. White tried to build.
« Last Edit: 09/13/2017 10:17 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
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Online Rodal

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...Need to also answer why, with constant Rf power, the positive displace force apparently completely stopped, disappeared,...
it depends on what is going, for example it could be an artifact of multipactor saturation due to debunching. The EM Drive as described in Shawyer's reports has been a black box with no reported measurements of what is going on inside it  ;).  In your message you write "2 watts" (for Jamie) but the power in Shawyer's experiments is way over that....

(*) SeeShells had proposed internal measurements to understand what is going on...
« Last Edit: 09/13/2017 10:38 PM by Rodal »

Offline TheTraveller

...Need to also answer why, with constant Rf power, the positive displace force apparently completely stopped, disappeared,...
it depends on what is going, for example it could be an artifact of multipactor saturation due to debunching. The EM Drive as described in Shawyer's reports has been a black box with no reported measurements of what is going on inside it  ;).  In your message you write "2 watts" (for Jamie) but the power in Shawyer's experiments is way over that....

(*) SeeShells had proposed internal measurements to understand what is going on...

Jose,

The dynamic displacement data I posted was created with 2Wrf as per Jamie's report.

Roger has shared only one dynamic report, that being for the Demonstrator EmDrive on his rotary test rig which allowed continual free acceleration. He has not shared data from testing on torsion wire based test devices that I know of.

Jamie and I did discuss this data with Roger. He commented it was representative of what he would expect from Jamie's test rig. Roger encouraged Jamie to build a spherical cavity so to increase cavity Q and force generation. Which Jamie has done.

« Last Edit: 09/13/2017 11:39 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline TheTraveller


I've made no secret of my distress over the unsubstantiated claims of thrust to power ratios, but this is one of the ideas that I think is actually credible; it's one of the most consistent anomalies across EM drive experiments.
Which can also be explained by a number of experimental artifacts that include significant time delays: thermal diffusion through the materials involved (an effect which would also be present in vacuum, governed by the density and thermal conductivity of the materials involved) and thermal convection (not present in high vacuum, and governed by the gas density and thermal conductivity as well as any latent heat of vaporization of liquid, for example humid air) being notorious among them.

So the clarity of
Quote
clearly shows the "stop accelerating
is in the eye of the beholder unless this is verified by other independent means.

It's far from proven, for sure. The better word to use would have been plausible, rather than credible. My bad!

Hi RS,

I'll accept plausible.
And yes I'll accept far from proven.
At least we are moving in the right direction.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Online meberbs

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Jamie and I did discuss this data with Roger. He commented it was representative of what he would expect from Jamie's test rig.
But it is not representative of what would happen if the force generation stopped when the acceleration stopped. In that case, the drive would return straight back to the null position from the first peak (and oscillate around it) rather than oscillating around the forward position.

As for what could be causing the displacement, you have to remember that while it is only 2W of power, it is also only equivalent to a couple of microNewtons of force. The end of the generation of the apparent force does not correspond to the drive reaching 0 acceleration or to the end of the RF power. This is not an encouraging piece of data for the emDrive working.

Offline Monomorphic

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I had to build a mini-enclosure so I can calibrate the calibration coil.  :o  First pulse was measured at ~3mg (~30uN). It's nice when things go right the first time! I should be able to get 10uN pulses or less working reliably by moving the ferromagnetic material further away from the coil. Pretty simple really, but it was complicated by the fact that I want to be able to send signals manually from both my workshop and my office two floors above.  Electrostatic fins were not practical as the spacing required is too small for a pendulum and synchronizing two isolated power systems for high voltage pulses is also not practical.

« Last Edit: 09/14/2017 01:11 AM by Monomorphic »

Offline jmossman

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Jamie and I did discuss this data with Roger. He commented it was representative of what he would expect from Jamie's test rig.
But it is not representative of what would happen if the force generation stopped when the acceleration stopped. In that case, the drive would return straight back to the null position from the first peak (and oscillate around it) rather than oscillating around the forward position.

As for what could be causing the displacement, you have to remember that while it is only 2W of power, it is also only equivalent to a couple of microNewtons of force. The end of the generation of the apparent force does not correspond to the drive reaching 0 acceleration or to the end of the RF power. This is not an encouraging piece of data for the emDrive working.

Hi Meberbs, TT,

I realize the following has been discussed in detail in previous threads, but I'd like to quickly summarize again for others who may have joined us since the original discussion/analysis.

Oscillating around the forward position suggests two things:
1) a force stopped
2) a background force(s) remains

Whether the "force stopped" is from the emDrive working (i.e. on->off) has yet to be established.  Shifting of the center-of-mass due to thermal expansion is one such alternative explanation (which can actually occur at the speed-of-sound in a material, unlike what many might incorrectly assume to be a slow thermal process).  A possible background force could be a "thermal balloon" effect from the trapped heated air inside of the copper frustum.

However, oscillating around the forward position cannot be used to solely exclude "emDrive working" from the possible explanations.

This forum has been patiently waiting for more experimental data from Monomorphic, Seeshells, and others in hopes of being able to isolate how many "forces", their various magnitudes, and their correlation to things like Radio Frequency (RF) start/stop, external vibration, and orientation of device-under-test to Earth's magnetic field... just to name a few.

Best regards,
James
« Last Edit: 09/14/2017 01:26 AM by jmossman »

Online meberbs

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However, oscillating around the forward position cannot be used to solely exclude "emDrive working" from the possible explanations.
Of course. In fact for an underdamped system (the preferred measurement mode) this is the expected result of a working drive. I was pointing it out in this case to show that the force did not stop when the acceleration reached 0 like TT claimed.

The main reason I don't find this to be convincing evidence of a working drive is that the force does stop before the RF, but for no apparent reason (acceleration had passed through 0 and reversed multiple times without the force stopping.)

Online spupeng7

Does a gravity wave/space-time ripple transfer momentum?

Bob,
nice conversation starter but nowhere in the consequent conversation did I see mention of the primary difference between gravity and gravity waves. The difference being that gravity obviously engenders momentum, proportional to the product of the masses involved and inversely proportional to the square of their separation, whereas gravity waves are reciprocating and the momentum they transfer must necessarily sum almost to zero over time, due to their own contra-acting dichotomy. Assuming that this was just assumed but thought I might mention it anyhoo  ;)
Optimism equals opportunity.

Online spupeng7

(...)
Meberbs,

Why do you feel that it is your job to take down TT? What's in it for you? All you have to do is state you assertions (which you already have done), then patiently wait for proof of a working/not working EMDrive. Then you can triumphantly come out and claim vindication. You don't have to take over over the thread and you don't have to play the role of physics Messiah. The truth will reveal itself on its own.

Having such strong assertions regarding our current understanding of physics will only serve to make for an even harder fall if EMDrive does in fact work. If EMDrive works, then we will be able to safely assume that you (as well as all of us) do not know as much as we think we do. We could be at a point in physics comparable to our knowledge of physics pre-Albert Einstein.

Bottom line is, Let it go. This debate will not be settled with words, it will be settled with hardware.
moreno7798,
the truth will indeed reveal itself (if we live long enough) though if emdrive really is true it won't be so much a fall as a float  ;D  and I should stand up for my fellow Aussie so I mostly agree with you, but, TT's bedtime does suggest that he resides in the general longitude of the UK. Meantime bless him and everyone else who employs their own skill set to try to find the true truth beneath this riddle.
Optimism equals opportunity.

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