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#820 by Rodal on 02 Apr, 2016 02:43
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...BTW Cullen 15 is just an equation and you have no experimental proof, that you have presented, that it doesn't work, should not be applied, to the radiation pressure generated on the end plates of a frustum. It would seem all you have is your opinion that it should not be applicable to the effect Roger used it to explain. ...
To clarify again:
I did not just express an opinion. I referred to standard textbooks like Collin's and Jackson's regarding the fact that the electromagnetic resonance of a closed cavity (as for example the EM Drive) involves a completely different solution of the electromagnetic fields than for an open waveguide. For example take a look at the equations for a) the natural frequencies of a waveguide vs. a closed cavity and b) the mode shapes for a waveguide vs. a closed cavity. Since the expressions for the electromagnetic fields are different, so are the electromagnetic stresses, and Poynting vector's expressions different. See the classic book of Arnold Sommerfeld "Electrodynamics" Volume III.
Concerning experiments, the fact that the electromagnetic field distribution is different between an open waveguide than in a closed cavity is a well established experimental fact. So is the fact that, under steady state resonance a closed cavity has standing waves in the longitudinal direction while a waveguide (discussed by Cullen) has no standing waves in the longitudinal direction).
__________
Added:
Eq. 15 in Cullen's follows from Maxwell's equations under the assumptions of:
1) a perfect mirror surface (thus the factor of 2 which follows from the momentum of the incident and reflected wave energies). In reality there will be some wall losses
2) A simple plane electromagnetic wave. The wave inside the frustum hitting the end plate may not be a plane wave.
3) Steady state conditions. Under transient conditions Eg. 15 is inapplicable since the equations of motion involve the time derivative of the Poynting vector and the divergence of Maxwell stress (as shown with Meep analysis in previous EM Drive threads). During steady state resonant conditions in a closed cavity, the situation would be one of standing waves. Under standing waves for a closed cavity (instead of an open waveguide discussed by Cullen) please refer to Greg Egan's solution: http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.html -
#821 by Rodal on 02 Apr, 2016 02:48
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...
Yes, I understood that there will be no contact, and that there will be a gap. That's why I wrote "if close enough",
Amazing statement, really amazing.
I went to some length to explain the experimental setup and that the side walls and upper end plate would not touch the lower end plate. I guess you did not bother to read what I had posted & have no real idea how I will conduct the experiment.
To make it very simple there will NO CONTACT between the frustum side walls and the end plate under test.
Please review the attached.Perhaps you will measure the thermal expansion of the truncated cone, if close enough, as suggested by Mr. Li, resulting in force measurements due to thermal expansion.
in other words, if the "small gap" between the frustum walls and the end plate is smaller than the thermal expansion of the frustum, then once it expands (induction heating occurring at the speed of light and thermal expansion occurring at the speed of sound) the gap will be closed. If the gap closes due to thermal expansion, then you have contact stresses between the walls and the endplates, and those contact stresses can be transmitted to the bottom plate and measured by the force measurements.
I have no idea how you are planning to support the frustum above the bottom plate. I have no idea about the stiffness of your support. If the gap closes due to thermal expansion and your support is stiff, you will be measuring contact stresses due to thermal expansion. If the support stiffness is more compliant than the stiffness of the frustum, upon contact, you will be measuring the stiffness of the support as well.
If you are not planning to support the frustum above the bottom plate, then there will be no gap, because the weight of the frustum will eliminate the gap (except for inaccurate lack of finish allowing gaps between contact points). The weight of the frustum is much higher than the electromagnetic pressure generated inside it.
Concerning having no idea what you will actually do, that's correct: you are the one conducting the experiment and you did not provide the needed information to make a stress-analysis. One would have to actually know ahead of time what is the experimental gap in your experiment (your drawing just stated "very small gap"
), the thermal expansion coefficient of the material of your frustum, the thickness and dimensions of the frustum, the power applied and a number of other variables (none of them provided), to know whether the gap would close or not. (*)
Concerning <<Amazing statement, really amazing.>> please don't ask me to answer any further questions about me having to guess the outcome of your experiment: an experiment that only you know how it is going to be conducted.
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(*)
As shown in these threads with computational models, the gap between the walls and the end plate will leak electromagnetic radiation from the inside to the outside, even if the gap is small (your drawing just says "small gap" providing no dimensions). The larger the gap the greater the leakage. The electromagnetic fields will be affected and thus they will not be the same as in a closed sealed cavity.
One would have to model this (with Meep, FEKO, COMSOL, ANSYS, or another numerical method), and calculate the electromagnetic stresses, to know what stress the end plate will actually experience, if the gap does not close due to thermal expansion.
Also as previously warned, such leaking electromagnetic radiation is a health hazard. Experiments with monkeys have shown very severe effects, including death of monkeys at radiated powers of around 100 watts and above, when in close proximity to their brains. (You show no shielding in your drawing). -
#822 by Tellmeagain on 02 Apr, 2016 04:29
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.....
Also as previously warned, such leaking electromagnetic radiation is a health hazard. Experiments with monkeys have shown very severe effects, including death of monkeys at radiated powers of around 100 watts and above, when in close proximity to their brains. (You show no shielding in your drawing).
I thought the gap was between the end plate and the sensors when I asked the questions. If it is between the side wall and the end plate, yes microwave power will be radiated from the gap. If the gap is close enough, electric arc across the gap may be seen. One solution could be to close the gap with mercury or less toxic liquid metal alloy. But they have surface tensions, which will make it hard (but not impossible) to measure the radiation pressure. -
#823 by ThinkerX on 02 Apr, 2016 04:39
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Possibly replicating Shawyers rotating rig might be a better option for Traveler?
Doctor Rodal, would you agree with that? -
#824 by ThinkerX on 02 Apr, 2016 04:46
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Did Todd get some ideas from the forum's discussion or is this not related at all?
In any case, this looks like a very fine work. Congratulations Todd!
I'm more and more getting the (yet unconfirmed) feeling that these phenomena of anomalous thrust (as I said, if confirmed) may have something to do with altering the vacuum state using EM energy, and as such, it is just the first of a family of devices using the same set of phenomena for achieving much more impressive effects.
It may be nothing at all, but it may be something bigger than we think. In any case, thank you guys for the ride!
As I recollect, Todd had a long running mathematical duel going with another poster, Delta Mass.
Todd got called out several times for errors in his work, some fairly trivial (misplaced signs), others more fundamental. There was a long dispute over notations which infuriated several of the math types here.
Given this, I really hope he had somebody mathematically competent - preferably several somebodies - go over the equations before submitting the paper.
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#825 by Rodal on 02 Apr, 2016 04:47
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Possibly replicating Shawyers rotating rig might be a better option for Traveler?
Yes, I am much more interested in the results of the rotating rig with batteries, that would be a most interesting test, but of course everybody is free to do what they please, and they should not have to cater to anyone else's interests.
Doctor Rodal, would you agree with that? -
#826 by TheTraveller on 02 Apr, 2016 04:52
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.....
Also as previously warned, such leaking electromagnetic radiation is a health hazard. Experiments with monkeys have shown very severe effects, including death of monkeys at radiated powers of around 100 watts and above, when in close proximity to their brains. (You show no shielding in your drawing).
I thought the gap was between the end plate and the sensors when I asked the questions. If it is between the side wall and the end plate, yes microwave power will be radiated from the gap. If the gap is close enough, electric arc across the gap may be seen. One solution could be to close the gap with mercury or less toxic liquid metal alloy. But they have surface tensions, which will make it hard (but not impossible) to measure the radiation pressure.
No arcs. Mode excited is TE013. No eddy currents are generated across the gap. All eddy curents circulate around the inside of the end plate or around the side walls as circular bands.
The air gap will be much smaller than the diameter of the holes on a microwave door. Will of course check for leaks, plus I never get closer than 1 mtr to the frustum even though most of my testing work is done using 78mW of Rf power. The Rf amp steps up in 1dBm increments from 78mW to 100W. This is NOT a magnetron.
Very high degree of control over both power level and freq. I dial up what is needed & get it delivered inside the frystum, plus get real time forward & reflected power levels as measured & reported by the Rf amp. Not much guessing. Know what is happening. -
#827 by TheTraveller on 02 Apr, 2016 05:07
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Possibly replicating Shawyers rotating rig might be a better option for Traveler?
Doctor Rodal, would you agree with that?
I'm doing that as well.
The rotary test rig will measure energy used / consumed during constant angular acceleration versus kinetic energy gained from increased angular velocity.
Will answer the CofE question.
The end plate radiation pressure experiment is designed to test if Roger's use of Cullen 15 & classical microwave guide wavelength equations do, as Roger claims, properly calculate the end plate radiation pressure generated inside a resonant EmDrive that is generating a reaction force.
2 very different experiments that will start to deliver experimental data to further understand why the EmDrive generates propellantless accelerate force and start to show if Roger's theory stands up to experimental data.
You see I have reached stage 1 & have measured ~8mN of reaction force from ~95W Rf. So I know it works. How to better understand how & why it works.
All of which will add credibility when I publish by data.
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#828 by FattyLumpkin on 02 Apr, 2016 06:18
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Were the large ends of these tapered waveguides "closed off" in the same way a rectangular trapezoidal prism EM drive unit is, would the same EM effect (thrust) be produced? ...given injection of RF a the small ends
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#829 by Rodal on 02 Apr, 2016 13:46
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...You see I have reached stage 1 & have measured ~8mN of reaction force from ~95W Rf. ...
To put these reported numbers in context, for comparison:
Force = 8 miliNewton
Power Input = 95 Watts
Force/PowerInput = 84 mN/kW
Force/Power Multiple over Photon Rocket = 25,200
This is
3 times greater than Ad Astra VASIMR VX-200 with argon propellant
Comparison with non-Null claims on EM Drive:
428 times greater than reported by DIY Dave Distler
30 times greater than reported by DIY Iulian Berca
515 times greater than Tajmar's beam balance reports at ambient conditions
16 times greater than NASA Brady, White, March, Lawrence, and Davies TM212 dielectric ambient conditions
4 times greater than NASA Brady, White, March, Lawrence, and Davies TE012 dielectric ambient conditions
1 to 1/3 of reported SPR Ltd, R. Shawyer, Demonstration TE012
source of information for comparison, see:
http://emdrive.wiki/Experimental_Results
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#830 by otlski on 02 Apr, 2016 13:58
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Possibly replicating Shawyers rotating rig might be a better option for Traveler?
Doctor Rodal, would you agree with that?
I'm doing that as well.
The rotary test rig will measure energy used / consumed during constant angular acceleration versus kinetic energy gained from increased angular velocity.
Will answer the CofE question.
The end plate radiation pressure experiment is designed to test if Roger's use of Cullen 15 & classical microwave guide wavelength equations do, as Roger claims, properly calculate the end plate radiation pressure generated inside a resonant EmDrive that is generating a reaction force.
2 very different experiments that will start to deliver experimental data to further understand why the EmDrive generates propellantless accelerate force and start to show if Roger's theory stands up to experimental data.
You see I have reached stage 1 & have measured ~8mN of reaction force from ~95W Rf. So I know it works. How to better understand how & why it works.
All of which will add credibility when I publish by data.
Might i suggest a few things.
For the three force sensor arrangement, see if you can borrow a FLIR handheld camera to actively monitor your experiment. The data could be handy if corrections need to be made.
For the rotary test rig; I assume air bearings are being used. If the bearing consists of a flat thrust bearing coupled to a cylindrical bearing; this creates a test apparatus constrained to a single axis of rotation. Such a set-up is easy to use but is subject to gravity pendulum. Meaning any offset CG combined with a very slight out of level condition will always try to find the "low spot" in the rotation. Gravity induced torque and resultant acceleration will muddy the results. One way to mitigate this is to ensure you allow the experiment enough time to rotate the assembly several turns so that thrust is forcing it uphill as well as down.
If the bearing consists of a hemispherical air bearing by itself, No such axis of constraint exists and there will be no gravity pendulum effect.
In either bearing configuration, motoring or self induced rotation (a turbine effect from air flow) can exist. This phenomena should be investigated and characterized ahead of time. Work reversal is a must for a test like this meaning the experiment should be turned around to produce both CW as well as CCW torque so that the average result represent the true net.
In either bearing configuration another phenomena, that of preferred position can manifest. Preferred position is when an eccentric rotor and an eccentric stator attempt to find a state of equilibrium where all pressures in the gap are equal. Most typically this is a two-lobed effect where the bearing prefers to rotate to two clocking position, oscillate slowly (minutes or hours) and come to an eventual rest. Enough time and full rotations mitigate this.
Be certain to use a well regulated pneumatic supply so that all of these error sources can be characterized because many are pressure dependent. If air compressors are the source, have a tank in between to lessen input fluctuation swings and to stabilize temperature. If using LN to GN2 or similarly expanding gas, beware of the chilling effect of gas expansion, run long lines through a water bucket heat exchanger.
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#831 by Notsosureofit on 02 Apr, 2016 14:34
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@ RODAL
Would you happen to know if the data shown in the April 2014 chart "Shawyer 2nd Gen Conical Cavity Operating Modes:" by Frank Davies (Eagleworks Lab Conical Resonant Cavity Modes-2.jpg) is available in tabular form ?
Thanks
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#832 by Rodal on 02 Apr, 2016 14:46
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No sorry. I looked through the reports to make sure, but to my knowledge, that data has only been released in graphical form, as per the chart "Shawyer 2nd Gen Conical Cavity Operating Modes:" by Frank Davies, which I attach here, so the audience can appreciate what we are discussing:
@ RODAL
Would you happen to know if the data shown in the April 2014 chart "Shawyer 2nd Gen Conical Cavity Operating Modes:" by Frank Davies (Eagleworks Lab Conical Resonant Cavity Modes-2.jpg) is available in tabular form ?
Thanks
I understand the predicament, since I have inspected that figure in the past to ascertain specific numbers from it. It would certainly be nice to have that data in numerical form
. It represents quite a lot of computer runs: a huge range in geometry from a cone to a truncated cone to a cylinder, and lots of mode shapes.
Frank Davies computer runs in this figure shows many interesting things, for example that the truncated cone does resonate even when the small diameter is below the cut-off prescription from Shawyer (that is known to apply only to open waveguides and not to closed resonant cavities). (See on the horizontal axis, the resonant modes for small diameter approaching a cone, towards the left of the horizontal axis). The resonant frequency below the cut-off for waveguides, is at a higher natural frequency.
The natural frequency increases as the shape goes from a cylinder (right of the horizontal axis) to a cone (left of the horizontal axis). The increase in natural frequency as the shape becomes conical is monotonic for most mode shapes (except a few mode shapes that have a non-monotonic change).
Best regards, -
#833 by Notsosureofit on 02 Apr, 2016 14:51
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@ TheTraveller
WRT the measured ~8mN of reaction force from ~95W Rf, would you be able to provide data for the mode, cavity dimensions, theoretical Q and obtained Q ? I'm looking at some commonalities between the Shawyer and Notsosureofit mode dependance.
Thanks -
#834 by TheTraveller on 02 Apr, 2016 15:41
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Possibly replicating Shawyers rotating rig might be a better option for Traveler?
Doctor Rodal, would you agree with that?
I'm doing that as well.
The rotary test rig will measure energy used / consumed during constant angular acceleration versus kinetic energy gained from increased angular velocity.
Will answer the CofE question.
The end plate radiation pressure experiment is designed to test if Roger's use of Cullen 15 & classical microwave guide wavelength equations do, as Roger claims, properly calculate the end plate radiation pressure generated inside a resonant EmDrive that is generating a reaction force.
2 very different experiments that will start to deliver experimental data to further understand why the EmDrive generates propellantless accelerate force and start to show if Roger's theory stands up to experimental data.
You see I have reached stage 1 & have measured ~8mN of reaction force from ~95W Rf. So I know it works. How to better understand how & why it works.
All of which will add credibility when I publish by data.
Might i suggest a few things.
For the three force sensor arrangement, see if you can borrow a FLIR handheld camera to actively monitor your experiment. The data could be handy if corrections need to be made.
For the rotary test rig; I assume air bearings are being used. If the bearing consists of a flat thrust bearing coupled to a cylindrical bearing; this creates a test apparatus constrained to a single axis of rotation. Such a set-up is easy to use but is subject to gravity pendulum. Meaning any offset CG combined with a very slight out of level condition will always try to find the "low spot" in the rotation. Gravity induced torque and resultant acceleration will muddy the results. One way to mitigate this is to ensure you allow the experiment enough time to rotate the assembly several turns so that thrust is forcing it uphill as well as down.
If the bearing consists of a hemispherical air bearing by itself, No such axis of constraint exists and there will be no gravity pendulum effect.
In either bearing configuration, motoring or self induced rotation (a turbine effect from air flow) can exist. This phenomena should be investigated and characterized ahead of time. Work reversal is a must for a test like this meaning the experiment should be turned around to produce both CW as well as CCW torque so that the average result represent the true net.
In either bearing configuration another phenomena, that of preferred position can manifest. Preferred position is when an eccentric rotor and an eccentric stator attempt to find a state of equilibrium where all pressures in the gap are equal. Most typically this is a two-lobed effect where the bearing prefers to rotate to two clocking position, oscillate slowly (minutes or hours) and come to an eventual rest. Enough time and full rotations mitigate this.
Be certain to use a well regulated pneumatic supply so that all of these error sources can be characterized because many are pressure dependent. If air compressors are the source, have a tank in between to lessen input fluctuation swings and to stabilize temperature. If using LN to GN2 or similarly expanding gas, beware of the chilling effect of gas expansion, run long lines through a water bucket heat exchanger.
Magnetic thrust bearing. Expected force 0.4N. Rapid acceleration from 0 rpm to at least 120 rpm or more. Total mass around 20kg. 1m diameter table. Totally self contained. On board batteries. Phase change waste heat dump. Rf comms. This is not several Snowflakes (~30uN each) of force level stuff.
Holding the frustum in your hands, you will be able to feel the 40g of force pulsing on and off. -
#835 by TheTraveller on 02 Apr, 2016 16:00
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@ TheTraveller
WRT the measured ~8mN of reaction force from ~95W Rf, would you be able to provide data for the mode, cavity dimensions, theoretical Q and obtained Q ? I'm looking at some commonalities between the Shawyer and Notsosureofit mode dependance.
Thanks
Frustum data attached. Flanges were not built. Frustum ends were ground flat. End plates used gravity for attachment. All internal surfaces were highly polished.
Measured Ql, doing it the way Roger suggests, was approx 8,000. Not very good. Don't believe hand built frustums will work unless the builder gets lucky. Roger has suggested max dimensional build variations of +- 10x skin depth.
According to Roger's equation F = (2 Qu P Df) / c the force predicted as per the Q was 6.6mN with a Df of 0.65. Measured was approx 8mN after some effort to get it as high as possible from the existing build by trying a few tricks to improve end plate alignment.
My 100W Rf amp operates from 500MHz to 3GHz (never tested the extremes) so operating at 2.4GHz was not an issue.
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#836 by Rodal on 02 Apr, 2016 16:04
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...Magnetic thrust bearing. Expected force 0.4N. Rapid acceleration from 0 rpm to at least 120 rpm or more. Total mass around 20kg. 1m diameter table. Totally self contained. On board batteries. Phase change waste heat dump. Rf comms. This is not several Snowflakes (~30uN each) of force level stuff.
If somebody can demonstrate a totally-self contained, battery operated, (*)EM-Drive closed-cavity that continuously self-accelerates in a rotary platform (@ constant acceleration), that can be checked by others, this test will be so amazing and surprising that a theoretical explanation is secondary IMHO (at this point in time).
Holding the frustum in your hands, you will be able to feel the 40g of force pulsing on and off.
The theoretical "why it works" effort can follow after such an amazing demonstration !
Both funding sources (venture and institutional), and the engineering aerospace community are foremost interested in whether something works and whether it can be used for propulsion purposes. That's why when an X-Prize was discussed in the NSF threads for the EM Drive:
NASASpaceFlight.com Forum » General Discussion » New Physics for Space Technology » EM Drive X-Prize Planning
https://forum.nasaspaceflight.com/index.php?topic=37563.0
the emphasis from the venture capitalists was on independently-verifiable-demonstration of the constant self-acceleration claim without using propellant exhaust or using external fields, rather than on "theoretical explanation".
_________
(*) The totally self-contained battery-operated condition is of crucial importance to deal with:
* conservation of energy
* conservation of momentum
such that the center of energy-momentum be self-accelerated and be placed in the rotating platform itself. -
#837 by Eusa on 02 Apr, 2016 18:17
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I have my theory of vacuum energy quanta.
I appreciate if somebody could modify the em-drive to g-drive in the principals as shown above. My possibilities to construct cavity with magnetron are very weak. It would be interesting to know what were the results...
The thrust would be based on standing waves which guide quanta. The cavity form is a cone closed with spherical reflectors at top and bottom. The distance from bottom to top must be exactly the multiple of the wavelength of radiation.
If the cavity was filled with liquid or some medium without absorbing radiation and heat problems, it would cause more remarkable effect than a vacuum. -
#838 by Rodal on 02 Apr, 2016 18:56
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Is there a more extensive description giving more information?. If not so, can you supply more information on your theory of the g-drive and how you deal with conservation of momentum and conservation of energy? How can standing waves provide self-acceleration? Thanks
I have my theory of vacuum energy quanta.
The thrust would be based on standing waves which guide quanta. The cavity form is a cone closed with spherical reflectors at top and bottom. The distance from bottom to top must be exactly the multiple of the wavelength of radiation.... -
#839 by Eusa on 02 Apr, 2016 21:12
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I haven't published any paper on my quantized vacuum energy theory but I can describe it briefly.
Is there a more extensive description giving more information?. If not so, can you supply more information on your theory of the g-drive and how you deal with conservation of momentum and conservation of energy? How can standing waves provide self-acceleration? Thanks
I have my theory of vacuum energy quanta.
The thrust would be based on standing waves which guide quanta. The cavity form is a cone closed with spherical reflectors at top and bottom. The distance from bottom to top must be exactly the multiple of the wavelength of radiation....
Simply, there are the flux of the vacuum energy that define the amount of space. The speed of quanta stream in the flux is the limit speed c. Every inertial body have comoving standing waves as gravity field as flux gradient. Standing spherical waves guide the vacuum energy to the space-support so that massive matter can exist as inertial particles. So the quanta stream propagates not from the gravitating body but towards the body.
The standing gravity field is possible the same as magnetic field but not coherent. So in the g-drive spherical standing waves guide the vacuum quanta towards smaller reflector. Because the outer vacuum gravity flux must be balanced for the gravity field for the needs of gravitating objects, it's only way for the g-drive to accelerate to the same direction where the flux density was artificially thickened.
The energy and momentum are conserved via gravity field by accelerating other bodies. The changes in the gravity field propagates at speed of light.
), the thermal expansion coefficient of the material of your frustum, the thickness and dimensions of the frustum, the power applied and a number of other variables (none of them provided), to know whether the gap would close or not. (*)
. It represents quite a lot of computer runs: a huge range in geometry from a cone to a truncated cone to a cylinder, and lots of mode shapes.