Author Topic: EM Drive Developments - related to space flight applications - Thread 2  (Read 2099540 times)

Offline rfmwguy

  • EmDrive Builder (retired)
  • Senior Member
  • *****
  • Posts: 2165
  • Liked: 2681
  • Likes Given: 1124
Quick note on Iulian's test; this was his third attempt. Unless I'm missing something, wouldn't have any thermal effects have shown up on those earlier tests at least in some form or was his measurements not accurate enough to measure that small of an effect?

Not as quick note on the Internet. With all due respect to Dr. Rodal- his characterization of the Internet (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1375139#msg1375139) is a bit inaccurate. Yes, there are plenty of distractions to be had, but to those with developed critical thinking skills, the Internet can be a fantastic tool.

In fact, the Internet was invented *for discussions just like this one*. Scientists getting together to share information and collaborate in new ways across distance and experience. This discussion has been an amazing example of social science application of this tool. Besides Dr. Rodal and the EW team's contributions, there's been several DIYers, mathematicians, skeptics, and scientists of all strips all tossing in ideas.

But then, out of that, there's been WarpTech's now known 'Todd Conjecture'. SeeShell's waveform expertise, seeing microwaves in hot tubs. Iulian's new much-debated video. Contributions from around the world. All the people working together here that have been pushing the literal boundaries of human understanding.

Having watched the Internet grow from it's ARPA/DARPA days in the 70's and 80's through to the ubiquitous tool that it is today, seeing exploration like this happening is an amazing experience; no matter *what* comes of this EM drive experimentation.

Yes, it's a bit like the Tower of Babel come to life, millions of voices all reaching out at once. But the Internet is a tool. And like any tool used in the hands of those with critical thinking skills, it becomes a powerful tool indeed.

Keep up the good work! This is an amazing time in human history to be doing science.

Well said, kudos...the "interwebs" is ideal for collaborative efforts, especially for those with an independent mind and a healthy measure of nonconformity. So often, public and private institutions adopt a play it safe mode and demotivate folks...perhaps the next Einstein is already posting here  ;)


Offline aero

  • Senior Member
  • *****
  • Posts: 2736
  • 92129
  • Liked: 704
  • Likes Given: 236
The picture of the wire frame end plate of a frustum got me to thinking a little out of the box. If a frustum were constructed of screen wire, like a window screen - wire, not that plastic stuff, wouldn't it resonate, too? At very low power it could keep its shape but at higher power mightn't it measurably deform from the internal optical pressure? And since we know the strength of the screen wire and the optical pressure from plane waves, couldn't we determine whether or not there was excess force being generated?

Perhaps a more simple construction would be from a solid copper conic section and copper screens on the ends attached in such a way as to encourage the deformation.

My point being that so far, all of the experiments have been constructed to serve as a rocket engine, but no one has made an experiment to look at the forces directly. Might there not be a more suitable configuration to look at the cavity forces than the frustum? And if we knew for sure that strange forces existed wouldn't that help the effort?
Retired, working interesting problems

Online Rodal

  • Senior Member
  • *****
  • Posts: 5833
  • USA
  • Liked: 5901
  • Likes Given: 5249
The picture of the wire frame end plate of a frustum got me to thinking a little out of the box. If a frustum were constructed of screen wire, like a window screen - wire, not that plastic stuff, wouldn't it resonate, too? At very low power it could keep its shape but at higher power mightn't it measurably deform from the internal optical pressure? And since we know the strength of the screen wire and the optical pressure from plane waves, couldn't we determine whether or not there was excess force being generated?

Perhaps a more simple construction would be from a solid copper conic section and copper screens on the ends attached in such a way as to encourage the deformation.

My point being that so far, all of the experiments have been constructed to serve as a rocket engine, but no one has made an experiment to look at the forces directly. Might there not be a more suitable configuration to look at the cavity forces than the frustum? And if we knew for sure that strange forces existed wouldn't that help the effort?

That's a  great way to conduct research on optimization and to understand something complicated. It reminds me of how the first human powered plane design came about. The  Gossamer Condor beat the MIT design (that was based on analysis) by evolutionary refinement of the design based on a large number of tests.
« Last Edit: 05/19/2015 03:11 AM by Rodal »

Offline aero

  • Senior Member
  • *****
  • Posts: 2736
  • 92129
  • Liked: 704
  • Likes Given: 236
The picture of the wire frame end plate of a frustum got me to thinking a little out of the box. If a frustum were constructed of screen wire, like a window screen - wire, not that plastic stuff, wouldn't it resonate, too? At very low power it could keep its shape but at higher power mightn't it measurably deform from the internal optical pressure? And since we know the strength of the screen wire and the optical pressure from plane waves, couldn't we determine whether or not there was excess force being generated?

Perhaps a more simple construction would be from a solid copper conic section and copper screens on the ends attached in such a way as to encourage the deformation.

My point being that so far, all of the experiments have been constructed to serve as a rocket engine, but no one has made an experiment to look at the forces directly. Might there not be a more suitable configuration to look at the cavity forces than the frustum? And if we knew for sure that strange forces existed wouldn't that help the effort?

That's a  great way to conduct research on optimization and to understand something complicated. It reminds me of how the first human powered plane design came about. The  Gossamer Condor beat the MIT design (that was based on analysis) by evolutionary refinement of the design based on a large number of tests.
Probably wouldn't need to use screen, just ultra thin copper bases. They should deform in one direction or the other. The direction of the deformation would say a lot about the force. If an untra thin copper sheet deformed differently than a copper screen, that might say that the effect is happening within the skin depth of the copper? One might even be able to string thin wires in one direction only, a screen with all of the y-direction wires removed. Then using the lower resonance modes only, the screen deformation might show a pattern of the forces. Might not, too.

Oh well, I won't be doing such experiments so perhaps that's enough for this train of thought.
Retired, working interesting problems

Offline deltaMass

  • Full Member
  • ****
  • Posts: 955
  • A Brit in California
  • Liked: 671
  • Likes Given: 275
I'm betting that Iulian is going to measure the same -0.5 gm weight change after he's flipped it upside down, meaning he's measuring hot air. But I'm no big fan of throwing babies out with bathwaters. The next logical step would then be to put something (e.g. a big plastic bag) around the whole thing and make sure that it's a perfect seal. Then retest to see if there is any real thrust at all there.

Offline zen-in

  • Full Member
  • ****
  • Posts: 531
  • California
  • Liked: 468
  • Likes Given: 365
I would put my money on electromagnetic effects of the HV wires connecting the capacitor to the magnetron.  When current starts moving in those wires they will repel each other.  That can resolve itself as an upward force on the cavity.   If this is true then any adjustment of the position of the wires will change the measured force.

Offline SeeShells

  • Senior Member
  • *****
  • Posts: 2324
  • Every action there's a reaction we try to grasp.
  • United States
  • Liked: 2952
  • Likes Given: 2586
I wonder what, if anything would result if there were a perfectly cylindrical 1/4 wave stub on one side of the source emitter and a frustum at 3/4 wavelength long on the other side of the emitter. The 1/4 wave stub side on the big end would resonate, and the frustum would attenuate. Engineered asymmetry with a much simpler resonant cavity.

Todd D.
Is this the psychic blog? Great idea!  I had a similar thought and have been mulling it over on how to apply it still using the EM snow cone shape. I asked if anyone had thought of using 2 insertion sites into the cavity and the answer I got, it might be considered this next go around of tests.
I'm not sure a perfect cylinder would get the effects we're looking for. I think first is finding out what we are seeing that's causing this CoE and CoM abnormality, but it sure would be quite inexpensive to design, build and test so you could just to plug in and see. It would also give you some very solid baseline data from very well known formulas.

Offline dustinthewind

  • Full Member
  • ****
  • Posts: 581
  • U.S. of A.
  • Liked: 226
  • Likes Given: 255
I wonder what, if anything would result if there were a perfectly cylindrical 1/4 wave stub on one side of the source emitter and a frustum at 3/4 wavelength long on the other side of the emitter. The 1/4 wave stub side on the big end would resonate, and the frustum would attenuate. Engineered asymmetry with a much simpler resonant cavity.

Todd D.
Is this the psychic blog? Great idea!  I had a similar thought and have been mulling it over on how to apply it still using the EM snow cone shape. I asked if anyone had thought of using 2 insertion sites into the cavity and the answer I got, it might be considered this next go around of tests.
I'm not sure a perfect cylinder would get the effects we're looking for. I think first is finding out what we are seeing that's causing this CoE and CoM abnormality, but it sure would be quite inexpensive to design, build and test so you could just to plug in and see. It would also give you some very solid baseline data from very well known formulas.

I get the impression the current in the 1/4 wave stub moves with the electric field of the incoming radiation for constructive interference and the 3/4 frustum I am guessing would be working against the radiation and be attenuated.  Is this similar to a directional antenna array?  I am not quite seeing the picture but I think I might understand the concept. 

Offline TheTraveller

I have read the 3 papers many times. Where did she state that? In what table? The 2010 paper I linked and the attached table makes it VERY clear the highest thrust came with the highest Q.

BTW I doubt you can get a good frustum Q measurement using a broadband microwave source as the frequency is all over the place and not at 2.45GHz. So the observed bandwidth would be as wide as a barn door because the wide band magnetron output is as wide as a barn door.

I see now this was your assumption and not from the paper.

Again I state that if you read the 2010 paper, it is VERY clear the higher the Q, the higher the thrust. Nothing the Chinese nor Shawyer has presented goes against that.

As to how to get a frustum that has constantly varying internal wavelengths to resonate at each end plate, from a different applied Rf wavelength, well I'm working on that. Might be my secret squirrel secret sauce.
The only way the frustum can gain momentum from the EM waves inside is if those waves are attenuated on each cycle, asymmetrically.

Which is how I understand Shawyer's CofE theory, which he claims to have experimentally verified.

Frustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses, dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.

The frustum movement energy related Q energy loss is the energy that was converted into Kinetic.
« Last Edit: 05/19/2015 08:54 AM 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 deltaMass

  • Full Member
  • ****
  • Posts: 955
  • A Brit in California
  • Liked: 671
  • Likes Given: 275
Quote
Frustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.
I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.

Offline dillonthomas

  • Member
  • Posts: 1
  • San Francisco
  • Liked: 1
  • Likes Given: 0
Hello!

I've been reading this thread with enthusiasm for months now!  I had an idea/question that is bugging the heck out of me that I feel compelled to ask. I joined specifically to ask this question. Perhaps it will lend to the discussion.

Regarding the shape of the cavity. Would making the cavity the shape of a sphere provide any benefit Or maybe an oblong sphere, like an egg?  For some reason, I visualize having a controllable/shapeable interference pattern and waveguide  according to the strength and frequency of the microwaves while bouncing around inside a sphere. Or, perhaps, the question shows my ignorance of the subject.   :-[

I'm humbled and honored to be in the presence of all of you intellectual giants.

Dillon
« Last Edit: 05/19/2015 01:19 PM by dillonthomas »

Online Rodal

  • Senior Member
  • *****
  • Posts: 5833
  • USA
  • Liked: 5901
  • Likes Given: 5249
..
I was the one that said that optimizing for a higher Q is counterproductive for generating thrust, not Yang. Here is my logic;

The only way the frustum can gain momentum from the EM waves inside is if those waves are attenuated on each cycle, asymmetrically. The Q is the energy stored/loss per cycle. So increasing Q by decreasing the loss per cycle, effectively it MUST reduce the amount of attenuation such that there is less thrust transferred to the frustum. Alternatively, if you increase Q by storing more energy, without altering the amount of power attenuated, then there is more energy in reserve to draw from. If the system used PWM, it could sustain a longer duty cycle.

So there are advantages to higher Q that can produce a higher thrust, but optimizing Q at the expense of reducing the attenuation, will lower the thrust, IMO.
...
Excellent statement:  "The only way the frustum can gain momentum from the EM waves inside is if those waves are attenuated on each cycle, asymmetrically"

...

I wonder what, if anything would result if there were a perfectly cylindrical 1/4 wave stub on one side of the source emitter and a frustum at 3/4 wavelength long on the other side of the emitter. The 1/4 wave stub side on the big end would resonate, and the frustum would attenuate. Engineered asymmetry with a much simpler resonant cavity.

Todd D.

Resonant cavity for attenuating electromagnetic standing waves in an (open) waveguide.
Multiple frequencies of the standing wave may be attenuated by locating identical cavities at different antinodes along an (open) waveguide:

http://www.google.com/patents/WO1997038437A1?cl=en
« Last Edit: 05/19/2015 01:13 PM by Rodal »

Offline hhexo

  • Member
  • Posts: 31
  • An Italian in the UK
  • Liked: 24
  • Likes Given: 1
Probably wouldn't need to use screen, just ultra thin copper bases. They should deform in one direction or the other. The direction of the deformation would say a lot about the force. ...

Hm... interesting idea, but bear in mind that copper is very sensitive to thermal dilation.

If you made a very thin sheet of copper you'd have to find a way of cooling it down very effectively on the outside, otherwise it might be susceptible to a measurable deformation just due to the temperature increase when the system is on.
I guess that the additional forces due to the microwaves would contribute a tiny bit, and you might be able to separate the two effects, but it's a bit of an engineering challenge I think.

A screen is more easily cooled by air convecting through it, but it could possibly suffer from the same problem.

Offline Einstein79

  • Member
  • Posts: 11
  • Liked: 4
  • Likes Given: 0
Re: O09
« Reply #3753 on: 05/19/2015 01:35 PM »
Does the Flight Thruster have a slightly concave top and convex bottom? Would appear so from the gaps.

Enhanced the photo as much as I can for those wishing to try to extract dimensions as this photo is better that the original as it has no distortion.

If we can find the dimension<M

The big end most certainly should be convex and the small end concave, relative from the outside of course. The big end and small end radii should not be coincidence but offset having the small end radius much larger than the big end. In fact, it might be better for the small end to be flat.

If either end is flat, the bounce will introduce very significant phase distortion into the returning curved wave. For me it is hard to see that Shawyer ever used flat end plates INSIDE the cavity. As we never saw inside the cavity, what is to say he didn't use curved end plates inside and flat end covers outside? What he drew may not be what he built.

Sorry about that, did not think about the returning wave. The cavity that you posted with the same vertex for each end was my first thought anyway. Great job guys! I am trying to get things situated so I can help more.

Offline TheTraveller

Quote
Frustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.
I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.

Energy will flow from the Rf input, into the frustum, until the 5 TCs required to fill it. Then the only additional energy input will be to replace Q losses or until it moves and frustum stored energy is converted into kinetic.

When the frustum moves, it is no longer resonant at the non moving frequency and a new resonant frequency results. This is why, in the Flight Thruster, the Rf input frequency tracks changes in the frustum resonant frequency.

With a magnetron Rf source, the broadband frequency output can handle the change in resonant frequency. For the higher tuned, high Q Flight Thruster, the narrow band Rf generator must track the resonant frequency change so as to be able to replace frustum energy to kinetic energy conversion / loss to the frustum.

In some way I see the operation of the frustum like a parallel LC circuit where circuit impedance is maxed at resonance and circuit current is at minimum.

Then if one of the resonant circuit elements changes, resonant frequency changes and effective circuit impedance is no longer at max nor current no longer at min.

A frustum at resonance is like a parallel tuned circuit:
http://www.electronics-tutorials.ws/accircuits/parallel-resonance.html

Max impedance and min current at resonance. As the frustum moves it is no longer at resonance, impedance drops and current increases.

One subject is how does Shawyer do impedance matching of the frustum to the microwave source? He seems to do it by, in the case of his superconducting frustum patent by adjusting the input slot size. With the Flight Thruster he has this as per the attached:
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline txdrive

  • Member
  • Posts: 48
  • Liked: 47
  • Likes Given: 14
Ultimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.

White says microwaves interact with the quantum vacuum in some manner, emitting some kind of a jet. People had been arguing about that, while forgetting that this does not alleviate the need for the radiation pressure imbalance, meaning that his E and H solution at the surface of the cavity differs from one obtained with Maxwell's equations, by an amount such that you're getting what, a net force of over 50 uN from 50W at a Q factor less than 7000 or so?

The total radiation pressure on the inside of the cavity is on the order of 50W*7000/c , about 2000 uN , so we're talking good ol Maxwell being off by at least 2.5% somewhere in the cavity. It's sort of like having a mechanical perpetuum mobile that needs it's levers to violate the lever equation by at least 2.5% .

edit: Even worse, microwave photons can't simply be absorbed in the interaction with "aether" (then the momentum imbalance will be equal to the power absorbed in this interaction divided by c exactly, with same performance as a regular photon drive except for all the losses in the cavity walls). They have to interact elastically, which means they must lose just a part of their energy at once, which means you would have new photons of a lower frequency, which would make it even more blatantly obvious for devices that sense microwaves.
« Last Edit: 05/19/2015 02:31 PM by txdrive »

Offline Mike-F

  • Member
  • Posts: 4
  • England
  • Liked: 7
  • Likes Given: 0
Quote
Frustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.
I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.

So an easy way to test if the EMdrive works, would be to build a low power unit (1 watt or less). Then with the system powered and tuned move it! Any movement along  the thrust axis should have a corresponding effect on the cavity resonance. This may be far easier to detect and confirm than the  very small forces developed so far.

Mike

Online Rodal

  • Senior Member
  • *****
  • Posts: 5833
  • USA
  • Liked: 5901
  • Likes Given: 5249
The number of photons (N) inside a cavity is not conserved. A photon may collide with an electron on a wall, exciting it to a higher energy state, removing a photon. This electron may drop back to its lower level in a series of steps, each one of which releases an individual photon back into the cavity.  Although the sum of the energies of the emitted photons are the same as the absorbed photon, the number of emitted photons will vary.

The absorption (emission) of one photon might be accompanied by the emission (absorption) of more than one photon, as long as the frequency of the photons involved are such that the energy of the system remains constant.

N over volume, and the entropy density are proportional to the cube of the temperature of the photon gas, while the pressure and the energy density are proportional to the fourth power of its temperature. 

For black body radiation it can be shown that, as a result of this lack of constraint on the number of photons in the system, the chemical potential of the photons must be zero.

How does the Entropy/Information Bound Work?  http://arxiv.org/pdf/quant-ph/0404042

Decoherence via Dynamical Casimir Effect  http://arxiv.org/pdf/quant-ph/9910027

Thermodynamics of the Casimir effect  http://arxiv.org/pdf/quant-ph/9902074v1

Dynamical Casimir effect at finite temperature  http://arxiv.org/pdf/quant-ph/9906122
« Last Edit: 05/19/2015 06:31 PM by Rodal »

Offline TheTraveller

Ultimately what Shawyer's and White's theories amount to, is that there is a radiation pressure imbalance on the inside of the cavity, resulting in a net force, which is a non small fraction of the total radiation pressure on the inside of the cavity (more than 1%). Shawyer says it is in accordance with Maxwell's equations, which is flat out wrong.

Where is Shawyer wrong?

1) Is the cutoff wavelength different at the small and big ends or not?

2) Is the guide wavelength different at the small and big ends or not?

3) Is the group velocity different at the small and big ends or not?

4) Is the bounce force different at the small and big ends or not?

5) Is the bounce force at the big end greater than at the small end or not?

6) Is there a bounce force on the side walls or not?

Just trying to understand where you believe Shawyer is wrong?
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline txdrive

  • Member
  • Posts: 48
  • Liked: 47
  • Likes Given: 14
Quote
Frustum movement (increased Kinetic energy of the frustum from stored cavity energy) causes the cavity to detune, increasing Q energy losses,dropping Q, dropping impedance, causing more microwave energy to enter the cavity, causing increased energy draw from the primary electrical source. Conserving CofE.
I'm afraid electrical circuits don't work quite like that, although it must be said that it's indeed a valiant attempt at rationality. Typically, you see, anything that causes a source and a load to transition away from a matched state will result in less power being transferred from source to load, not more.

So an easy way to test if the EMdrive works, would be to build a low power unit (1 watt or less). Then with the system powered and tuned move it! Any movement along  the thrust axis should have a corresponding effect on the cavity resonance. This may be far easier to detect and confirm than the  very small forces developed so far.

Mike
Earth is rotating and orbiting the sun, and there's all sorts of electronic devices where nothing was ever observed to vary with the time of day, down to very high precision.

Tags: