Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1795650 times)

Offline Rodal

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...

In other words, does accelerating the frustum in one direction change the resonance mode, while accelerating in the other does not? And will the resonance mode significantly resist being changed?
For that to happen, the mechanical acceleration would have to be huge, since the electromagnetic field frequency is in the GHz range.  But, on the contrary, the reported EM Drive accelerations instead of being huge, it is extremely tiny: in the only EM Drive experiment that experienced significant rigid body motion: Shawyer's Demo on an air bearing, it takes several minutes for the EM Drive to complete a circumference,  Extremely small acceleration.


Maybe it is possible there could be vibrations in the GHz range.  There is radiation pressure  and microwaves are in the GHz range.  We also have that pressure amplified by the Q of the cavity and possibly phase relationships inducing vibrations.

The amplitude of mechanical vibrations on the EM Drive copper in the GHz range must be extremely, extremely small. 

The natural frequencies in the GHz range of the copper sheets used in these EM Drives are extremely high frequencies (as one can calculate using shell vibration theory).

We have to have some sense of proportion here, between someone saying just tap the end of the EM Drive and on the other hand GHz mechanical vibrations, otherwise the discussion is unfocused.

That's why I asked whether the EM Drive was an equal opportunity friend of all kinds of vibrations, regardless of amplitude and frequency.

Otherwise what is being proposed here, that nanometer amplitude vibrations are enough to get the EM Drive moving?

If nanometer amplitude vibrations are enough to set the EM Drive in motion, what prevents the EM Drive in any of the experimental studies from having experienced nanometer amplitude vibrations?

Frankly, between the proposal that the EM Drive somehow "knows" its velocity so that it cannot become a free-energy machine and this proposal that the EM Drive has to have an unspecified level of vibration amplitude and frequency to exert a force... well I better stop here. :)
« Last Edit: 06/24/2015 08:22 PM by Rodal »

Offline ZuluMoon99

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Somewhere I picked up the idea that international patents are an option.

Worked at UK Patent office back in the 80s, if memory serves me right you can file a patent in the UK and later file one at Geneva to cover Europe [WIPO] and the rest of the world.

Cannot remember if there are any restrictions on time from first filing though - things undoubtedly have changed since then.




Do not read following if not eaten yet...

As for the observation of very strange perpetual motion patents the 'best', if one can call it that, one that I saw,  involved thumb and bending over.  Suspect not granted...  I wonder why not....


Offline rfmwguy

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Somewhere I picked up the idea that international patents are an option.

Worked at UK Patent office back in the 80s, if memory serves me right you can file a patent in the UK and later file one at Geneva to cover Europe [WIPO] and the rest of the world.

Cannot remember if there are any restrictions on time from first filing though - things undoubtedly have changed since then.
...

WIPO has 31 months from priority date for UK patents, Time Limits for Entering National/Regional Phase under PCT Chapters I and II:

More info here:

http://www.wipo.int/pct/en/texts/time_limits.html

WIPO patent search: https://patentscope.wipo.int/search/en/search.jsf

Shawyer does have beam-former patents from the 90's registered there, Applicant: Marconi
« Last Edit: 06/24/2015 08:00 PM by rfmwguy »

Offline SeeShells

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Just needs some vibration.

The EMDrive is an inertial ratchet. Push it on the small end and it will oppose that push, moving into Generator mode. Push it on the big end and it will support that push, moving into Motor mode.
...

Ha!... It doesn't exert any thrust due to the microwaves because Maxwell's equations say it can't. But it does store energy and that energy will have a back-reaction when you push it, which will be just as asymmetrical as the cavity attenuation.

Well done. I'll accept that.

Like your bike wheel example, once you flip it into Motor or Generator mode, it will stay there as long as there is an external force, which can be just simple vibration.

If you look at this slide, Shawyer clearly shows the momentum generates no external Force.

This diagram "slide" you keep showing is wrong, period. I spent a lot of time crunching numbers over the past week and I did a proper relativistic analysis of this diagram, 3 different ways! Using SR velocity addition/subtraction, using Lorentz Transformations and using Maxwell's equations. I took the walls into consideration as well as the 2 end plates.

In all 3 instances, pw = 0. There is no residual momentum transfer to the frustum with microwaves. Sorry, it just doesn't work this way. The "proof" it doesn't work this way is in this strange behavior you are aware of, that it will not thrust unless you give it a push. If it actually worked the way this diagram says it does, it would not require a push to get rolling.

It is possible that pushing it backwards offers resistance such that it appears more massive, where pushing it forward it appears less massive and tends to accelerate easier. But who's going to give a satellite a "push" in space?
Todd

Ok, here goes. My love hate relationship with air bearings.

It was done on a air bearing, frictionless with known issues close to 0 rpm. I touch something on the stand... I breathe on it with a air bearing it starts moving and if the air bearing loading isn't uniform across the axis it will vortex the air between the plates and begin to move on its own... with acceleration. Push it the other way and because of the same rotating air vortexes pre-loading it will resist.

Do it on a pendulum or beam fulcrum or a pin bearing.
http://www.clag.org.uk/pics/bearing-interface/basic-standard-interface.gif

Shell

Offline deltaMass

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Air bearings are the best way to make a zero effect into something that looks like it does something.

You could put a dead ant on an air bearing and declare that you have thrust.
Of course, you have to lightly tap the ant first.  :'(

Offline SeeShells

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Air bearings are the best way to make a zero effect into something that looks like it does something.

You could put a dead ant on an air bearing and declare that you have thrust.
Of course, you have to lightly tap the ant first.  :'(
It can be a tough test fixture to make work properly. Even though I had years of working with them and I could have done one I choose not. BTW if it was a spider on the air bearing? It be dead spider!
Shell

Offline SeeShells

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Aero, did you get those numbers I sent a few posts ago? Can you use them?

Shell

Offline rfmwguy

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Air bearings are the best way to make a zero effect into something that looks like it does something.

You could put a dead ant on an air bearing and declare that you have thrust.
Of course, you have to lightly tap the ant first.  :'(
It can be a tough test fixture to make work properly. Even though I had years of working with them and I could have done one I choose not. BTW if it was a spider on the air bearing? It be dead spider!
Shell
Methinks we are in agreement that air bearings, digital scales (exclusively) and perhaps torsional twists are not the way to proceed with this thing. Its not only the cost, but the Occam's Razor deal (added complexity), K.I.S.S.

Offline SeeShells

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Air bearings are the best way to make a zero effect into something that looks like it does something.

You could put a dead ant on an air bearing and declare that you have thrust.
Of course, you have to lightly tap the ant first.  :'(
It can be a tough test fixture to make work properly. Even though I had years of working with them and I could have done one I choose not. BTW if it was a spider on the air bearing? It be dead spider!
Shell
Methinks we are in agreement that air bearings, digital scales (exclusively) and perhaps torsional twists are not the way to proceed with this thing. Its not only the cost, but the Occam's Razor deal (added complexity), K.I.S.S.
KISS rocks. BTW I'm going to put a digital scale at the other end of my beam about 12 foot away from the EMdrive and shield the drive with copper screen supported by a chicken wire and wood framed. Should do it.

Shell

Offline rfmwguy

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Air bearings are the best way to make a zero effect into something that looks like it does something.

You could put a dead ant on an air bearing and declare that you have thrust.
Of course, you have to lightly tap the ant first.  :'(
It can be a tough test fixture to make work properly. Even though I had years of working with them and I could have done one I choose not. BTW if it was a spider on the air bearing? It be dead spider!
Shell
Methinks we are in agreement that air bearings, digital scales (exclusively) and perhaps torsional twists are not the way to proceed with this thing. Its not only the cost, but the Occam's Razor deal (added complexity), K.I.S.S.
KISS rocks. BTW I'm going to put a digital scale at the other end of my beam about 12 foot away from the EMdrive and shield the drive with copper screen supported by a chicken wire and wood framed. Should do it.

Shell

Good plan, I cringed at the exposed cables to/from scale in kmls setup. Digital cables are notorious "EMF antennas" unless you get the expensive shielded types. Best just to keep at a distance imo. I designed a RF power meter with a DAC several years ago and found out first hand.

Online WarpTech

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Air bearings are the best way to make a zero effect into something that looks like it does something.

You could put a dead ant on an air bearing and declare that you have thrust.
Of course, you have to lightly tap the ant first.  :'(
It can be a tough test fixture to make work properly. Even though I had years of working with them and I could have done one I choose not. BTW if it was a spider on the air bearing? It be dead spider!
Shell
Methinks we are in agreement that air bearings, digital scales (exclusively) and perhaps torsional twists are not the way to proceed with this thing. Its not only the cost, but the Occam's Razor deal (added complexity), K.I.S.S.
KISS rocks. BTW I'm going to put a digital scale at the other end of my beam about 12 foot away from the EMdrive and shield the drive with copper screen supported by a chicken wire and wood framed. Should do it.

Shell

I'm sorry, but I've lost all hope that the microwave design can generate any significant thrust, now or in the future. The MOST that it could do is, given equal pressures front and rear, since there are higher losses on the big  end, it will make the pressure "dissipate" (not attenuate) faster. Then it will move forward in the opposite direction. But rapid heat losses are equivalent to poking a hole in it and letting the pressure leak out. High resistance and voltage drop allows magnetic flux to escape through the copper. It's not rocket science.
Todd

Offline deltaMass

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Are you implying that the fault is not systemic but lies purely with the choice of frequency (microwave being "bad")?

Online RonM

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Air bearings are the best way to make a zero effect into something that looks like it does something.

You could put a dead ant on an air bearing and declare that you have thrust.
Of course, you have to lightly tap the ant first.  :'(
It can be a tough test fixture to make work properly. Even though I had years of working with them and I could have done one I choose not. BTW if it was a spider on the air bearing? It be dead spider!
Shell
Methinks we are in agreement that air bearings, digital scales (exclusively) and perhaps torsional twists are not the way to proceed with this thing. Its not only the cost, but the Occam's Razor deal (added complexity), K.I.S.S.
KISS rocks. BTW I'm going to put a digital scale at the other end of my beam about 12 foot away from the EMdrive and shield the drive with copper screen supported by a chicken wire and wood framed. Should do it.

Shell

I'm sorry, but I've lost all hope that the microwave design can generate any significant thrust, now or in the future. The MOST that it could do is, given equal pressures front and rear, since there are higher losses on the big  end, it will make the pressure "dissipate" (not attenuate) faster. Then it will move forward in the opposite direction. But rapid heat losses are equivalent to poking a hole in it and letting the pressure leak out. High resistance and voltage drop allows magnetic flux to escape through the copper. It's not rocket science.
Todd

Don't give up until you see the data. There are very strong theoretical reasons why this won't work, but the issue remains that there is unexplained thrust. We should know soon from various experiments if the thrust is merely experimental error or if there is something going on.

Online aero

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Aero, did you get those numbers I sent a few posts ago? Can you use them?

Shell

Are you referring to the dimensions of your 6 sided cavity? If so, I saw them but as meep does not support arbitrary shapes, I would need to piece your cavity together with square plates angled properly, then cut the excess material with the "nothing" property. Those would be a bunch of commands like:

(make block (center 0 0 0)  (size 1 1 0)   (material metal) (axis 1 0 0))  )

where the center gives the x, y, z coordinate of the center of each face, Size is simple, just make height of the cavity and the width of a side at the base and thickness of the material. The trick is to align the axis so that the plate is angled like it should be. After that is done, to trim the corners just make a thick block of (material nothing) adjacent to the outer face of each plate, a little bit larger to trim all of the overhang. Else you won't see the shape of the model through all the extra pieces. Top and bottom can be modelled/capped with a disk, ie, a very short solid cylinder of the correct radius. Shortening the cavity would just involve moving the small end cap down, and the overhang cropped with a cylinder of nothing.

 That would take me significant time, probably a full day or two to debug it even if you give me all the numbers. I'll model it if I get an inspiration and the time. I would like to see the fields that meep calculates for that shape.

I'm trying to get some pretty pictures for rfmwguy right now but locating the antenna is a challenge. Do we have some antenna guys reading this who can tell me how long (in wavelengths) the dipole antenna should be, and how far from the back plate it should be placed (again, in wavelengths)? I'd appreciate your input.
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Offline dustinthewind

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For that to happen, the mechanical acceleration would have to be huge, since the electromagnetic field frequency is in the GHz range.  But, on the contrary, the reported EM Drive accelerations instead of being huge, it is extremely tiny: in the only EM Drive experiment that experienced significant rigid body motion: Shawyer's Demo on an air bearing, it takes several minutes for the EM Drive to complete a circumference,  Extremely small acceleration.


Maybe it is possible there could be vibrations in the GHz range.  There is radiation pressure  and microwaves are in the GHz range.  We also have that pressure amplified by the Q of the cavity and possibly phase relationships inducing vibrations.

The amplitude of mechanical vibrations on the EM Drive copper in the GHz range must be extremely, extremely small. 

The natural frequencies in the GHz range of the copper sheets used in these EM Drives are extremely high frequencies (as one can calculate using shell vibration theory).

We have to have some sense of proportion here, between someone saying just tap the end of the EM Drive and on the other hand GHz mechanical vibrations, otherwise the discussion is unfocused.

That's why I asked whether the EM Drive was an equal opportunity friend of all kinds of vibrations, regardless of amplitude and frequency.

Otherwise what is being proposed here, that nanometer amplitude vibrations are enough to get the EM Drive moving?

If nanometer amplitude vibrations are enough to set the EM Drive in motion, what prevents the EM Drive in any of the experimental studies from having experienced nanometer amplitude vibrations?

Frankly, between the proposal that the EM Drive somehow "knows" its velocity so that it cannot become a free-energy machine and this proposal that the EM Drive has to have an unspecified level of vibration amplitude and frequency to exert a force... well I better stop here. :)

Some good points. I was referring in particular to the paper below,

I am not a Shawyer fan but the Traveller defense could be not so crazy, look at the following paper:

Motion induced radiation from a vibrating cavity
http://arxiv.org/abs/quant-ph/9606029

We study the radiation emitted by a cavity moving in vacuum. We give a quantitative estimate of the photon production inside the cavity as well as of the photon flux radiated from the cavity. A resonance enhancement occurs not only when the cavity length is modulated but also for a global oscillation of the cavity. For a high finesse cavity the emitted radiation surpasses radiation from a single mirror by orders of magnitude.

I understand where your coming from as I really can't identify with a cavity not having any force because it is at rest, though the paper got me thinking. 

Edited:
I would like first to see better experimental verification by elimination of buoyancy (eliminated by turning upside down [already done]), convection currents (not solved yet but I was thinking put in a small insulated box), and pressure from heating (exhaust through small holes - maybe make holes so air velocity is slower when exhausted). 
« Last Edit: 06/24/2015 10:09 PM by dustinthewind »

Offline SeeShells

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Aero, did you get those numbers I sent a few posts ago? Can you use them?

Shell

Are you referring to the dimensions of your 6 sided cavity? If so, I saw them but as meep does not support arbitrary shapes, I would need to piece your cavity together with square plates angled properly, then cut the excess material with the "nothing" property. Those would be a bunch of commands like:

(make block (center 0 0 0)  (size 1 1 0)   (material metal) (axis 1 0 0))  )

where the center gives the x, y, z coordinate of the center of each face, Size is simple, just make height of the cavity and the width of a side at the base and thickness of the material. The trick is to align the axis so that the plate is angled like it should be. After that is done, to trim the corners just make a thick block of (material nothing) adjacent to the outer face of each plate, a little bit larger to trim all of the overhang. Else you won't see the shape of the model through all the extra pieces. Top and bottom can be modelled/capped with a disk, ie, a very short solid cylinder of the correct radius. Shortening the cavity would just involve moving the small end cap down, and the overhang cropped with a cylinder of nothing.

 That would take me significant time, probably a full day or two to debug it even if you give me all the numbers. I'll model it if I get an inspiration and the time. I would like to see the fields that meep calculates for that shape.

I'm trying to get some pretty pictures for rfmwguy right now but locating the antenna is a challenge. Do we have some antenna guys reading this who can tell me how long (in wavelengths) the dipole antenna should be, and how far from the back plate it should be placed (again, in wavelengths)? I'd appreciate your input.
Please please please it will be fine, don't go to all the trouble, that's a crazy amount of time.
If you want to run with it just do a quickie.
Just pick the maxD for the big and small plate.
Excircle radius (re):0.122   
Excircle radius (re):0.061   
Longitudinal between plates 0.4892

Simple dipole calculator I've used before...
http://www.csgnetwork.com/antennaedcalc.html

Online WarpTech

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Are you implying that the fault is not systemic but lies purely with the choice of frequency (microwave being "bad")?

No, I'm saying that the fault is because the big end is closed! If you had resonance on the cone without closing the big end, like rubbing your finger on the rim of a champagne glass, it would be a thruster. As it is now, it's just an energy storage device and possibly an inertial-damper.
Todd

Online aero

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Simple dipole calculator I've used before...
http://www.csgnetwork.com/antennaedcalc.html

Thanks shell.
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Offline rfmwguy

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Air bearings are the best way to make a zero effect into something that looks like it does something.

You could put a dead ant on an air bearing and declare that you have thrust.
Of course, you have to lightly tap the ant first.  :'(
It can be a tough test fixture to make work properly. Even though I had years of working with them and I could have done one I choose not. BTW if it was a spider on the air bearing? It be dead spider!
Shell
Methinks we are in agreement that air bearings, digital scales (exclusively) and perhaps torsional twists are not the way to proceed with this thing. Its not only the cost, but the Occam's Razor deal (added complexity), K.I.S.S.
KISS rocks. BTW I'm going to put a digital scale at the other end of my beam about 12 foot away from the EMdrive and shield the drive with copper screen supported by a chicken wire and wood framed. Should do it.

Shell

I'm sorry, but I've lost all hope that the microwave design can generate any significant thrust, now or in the future. The MOST that it could do is, given equal pressures front and rear, since there are higher losses on the big  end, it will make the pressure "dissipate" (not attenuate) faster. Then it will move forward in the opposite direction. But rapid heat losses are equivalent to poking a hole in it and letting the pressure leak out. High resistance and voltage drop allows magnetic flux to escape through the copper. It's not rocket science.
Todd

I hear you...my test runs should either confirm or refute your position, at least it will be part of the body of data...which is sorely lacking right now. As doc says, don't give up the ship until more data arrives. Hope for the best, prepare for the worst.

Offline SeeShells

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Are you implying that the fault is not systemic but lies purely with the choice of frequency (microwave being "bad")?

No, I'm saying that the fault is because the big end is closed! If you had resonance on the cone without closing the big end, like rubbing your finger on the rim of a champagne glass, it would be a thruster. As it is now, it's just an energy storage device and possibly an inertial-damper.
Todd
Take a break, read a book, go for a walk, a swim, anything but think, get stupid. ;) You have been buried in crunching numbers. Time to take a breather. I still think you have some great ideas that deserve more attention but your frustration needs you now.

I've been worried about the closed off back cavity too and I allowed for it to be opened up in my final tests with a grate. For I believe there is a difference between a solid metal barrier, a off tuned grate in the ways related to maxwell's equations, QV, evanescent waves and force vectors tunneling through that barrier and the interactions that can occur on the outside. I'm still digging into this and haven't got all the facts and figures in place but It looks promising.

Shell

 

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