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#1460 by francesco nicoli on 12 Oct, 2016 13:36
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from the patent :
Quote"a single crystal sapphire substrate is glued to the major end plate..."
Euh.. why the sapphire?
What special property does it have, that it is needed for the inside of the big plate?
funny answer: because sapphire drives price substantially up, so he can claim he did not build a working device because of lack of funding. Otherwise, if it were cheap, people would question "where is your working proof"?
kidding of course.
Looking forward to see it flying. if ever. But won't bet a pence on it. -
#1461 by WarpTech on 12 Oct, 2016 13:40
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Todd, I note you keep using a cylinder in your mathematical models. Yet, one of the very few things that is known about this device is that a symmetrical shape (cylinder) results in zero thrust. So why persist in using a shape that will not work?
Another thought that keeps crossing my mind these days: evanescent waves. Clear back to the first versions of these threads, electrical engineers with extensive experience kept saying over and over again that this device, according to what they knew, should generate massive amounts of evanescent waves. Yet, as I recollect, this line of inquiry kept getting dropped or put off. Rodal's summary of the one theory at the recent Colorado conference is the first mention of evanescent waves I recollect seeing here in a long, long while.
Another thing I have started wondering about in recent weeks are the 'surges' - difficult or impossible to repeat episodes of very high thrust. Shell mentioned one such, as did Traveler. Possibly rfmwguy and Yang as well. These episodes turn up in multiple efforts, yet remain a puzzle.
There is also the puzzle with the model work - the ones that over a period of a thousandth of a second, if that - show exponential asymmetrical forces building within the cavity. I have yet to see one of these simulations extended to several seconds, to gauge just how great these internal forces may become. There is a tendency here to dismiss these simulations as 'noise,' yet they also predict the various modes with fair accuracy.
Then there are the 'nulls' - the builds that either produced no 'thrust,' or 'thrust' indistinguishable from the noise level.
And finally, there are the vacuum tests, which seem to produce 'thrust' far smaller than that in an atmosphere.
To my mind, a successful theory for how this device works needs to account in some way for all of these elements.
Point 1) Why? Because Spherical harmonics and Hankel functions are beyond my mathematical capability and besides that. The procedure is the same, subtract the squared magnitude of the frequencies at either end of the frustum to determine the power lost. Conceptually, the result is identical. In Rodal's paper, he mentioned that there is no hard cut-off in the truncated spherical cone. No hard cutoff to me means that the frequency is free to shift depending on where it's at inside the truncated cone.
In a spherical truncated cone there will be attenuation and evanescent waves. These will result in losses. End result leads to the same equations. The difference in the squared magnitude of the frequencies to determine the power lost. Evanescent waves are simply waves that decay. They decay by doing work on the frustum, which "is" power lost from the cavity.
My explanation for the surges and nulls is the input frequency was dithered, not accurate or too high. If the input frequency is higher, there is more potential energy to decay to a lower frequency state. This can cause a surge. If the resonant frequency is the input frequency, or the input frequency is too low, the thrust should be null since there is no lower frequency to decay to. Compare the idea to a 2-state atom or a laser. The input frequency is the "pumped" state, where there is a population inversion. This provides a "Potential energy". When the energy decays to the lower frequency, it provides thrust.
And finally, air has mass that is also accelerated by the "g" field inside. Remove the air and F=ma is obviously reduced.
As for my thought experiment; in this example what difference will the shape make? I could've called the shape a cube or a sphere, it wouldn't matter provided the two masses start at opposite ends and are gravitationally attracted to each other.
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#1462 by Monomorphic on 12 Oct, 2016 13:44
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Looks like saphire has better thermal conductivity than quartz.
W/(m x K) at 300K:
Saphire: 23.1 parallel to optical axis, 25.2 perpendicular to optical axis
Quartz: 9.5 & 6.10 -
#1463 by WarpTech on 12 Oct, 2016 13:47
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Here's a thought experiment:
Consider a horizontal cylinder of length L, in free space, zero-g.
At each end of the cylinder is a mass M, which is large compared to the mass of the cylinder.
The mass on the left is firmly fixed to the end of the cylinder.
The mass on the right starts at the far right, but is free to float around in the cylinder.
If no external forces act on the system, the only force will be the gravitational attraction between the two masses. After a time, the two masses will accelerate toward each other, and eventually both will be in contact at the left end of the cylinder. Assuming the CM did not move... From the outside, it appears that the cylinder has accelerated and moved a distance L/2 to the right. Then stops, when the two masses meet and their momentum cancels out.
Consider the possibility that after some time, the movable mass M is dissipated as heat, into a heatsink on the left. Imagine a battery that feeds in a new mass M on the right side that is free to move in the cylinder. This is possible when using electromagnetic mass and it's momentum when injected is irrelevant. It just adds to the total mass.
http://www.feynmanlectures.caltech.edu/II_28.html
REPEAT ad nausea...
Momentum is conserved. Energy is conserved, and there is no propellant coming out the back except heat. It uses gravity to move itself. No fancy stuff, just gravitational attraction of one mass toward another, and a loss of mass though random heat exchange. Who disagrees with this and why?
Todd
What do you mean "no propellant coming out the back except heat"? Heat is a property of matter, not a substance. Do you mean thermal radiation? To dissipate the entire mass as radiation, you would need half of it to be antimatter, and if you directed that energy straight out the back you would get a lot of momentum out of it, enough to be moving at a fraction of light speed I believe.
The step where a battery feeds in a new mass sounds like magic to me. Where does this new mass come from? If it is coming from the battery, then the battery must start with mass greater than M and it loses mass M in creating that mass. And assuming the battery is attached to the cylinder to begin with you then have to go back and redo the original calculations accounting for that, and don't forget to add in the effect of moving that mass around as well.
I am not sure why you posted that link, but it talks about several subtle concepts, and has some intermediate conclusions that it later explains the issues with. Anything short of reading the whole thing will give you an incorrect impression. My attempt to summarize the conclusion of it is that mass of fundamental particles that are charged is in part due to the electromagnetic potential energy, but not entirely, and we don't know if there is a way to tell the difference or if it matters. (The specifics are more subtle than this, but you have to read the whole thing to get it.) Nothing in it changes what I said above about the mass having to already be in the mass of the battery, if the battery creates the mass.
Okay, so replace battery with a Solar Panel of negligible mass.
Do you understand a Capacitor gains weight when it is charged? If so, an Electric field contributes to its inertial mass. The EM Drive uses the inertial mass of the EM field inside it.
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#1464 by SeeShells on 12 Oct, 2016 13:53
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Good points rq3, but the mismatches on the Sapphire lattice depend on how the Sapphire and YCBO are bonded. Remember chips are made SoS (Silicone on Sapphire)from the patent :
He got the Helical antenna right on. (one a NSFer did for me by 3D printing July 2015)Quote"a single crystal sapphire substrate is glued to the major end plate..."
Euh.. why the sapphire?
What special property does it have, that it is needed for the inside of the big plate?
Saphire is a great thermal conductor and has a High dielectric constant (9.39 from 1.0 MHz to 8.5 GHz) a nice pick.
Shell
But according to the patent application, the sapphire is strictly a substrate for the superconductor. It never sees the EM field due to the YBCO film. If the idea was to have a thermally stable substrate, quartz would have been a better (and certainly less expensive) choice. Additionally, the lattice mismatch between single crystal sapphire (Al2O3) and YBCO is pretty severe. Not a good choice.
http://www.mt-berlin.com/frames_cryst/descriptions/sapphire.htm
My company extensively researched SOS and other uses for Sapphire as we were separating the dies with our equipment (10x faster than sawing or scribing). Even found a 100mm sapphire wafer we die separated on my old file system. (attached)
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#1465 by WarpTech on 12 Oct, 2016 13:54
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from the patent :
Quote"a single crystal sapphire substrate is glued to the major end plate..."
Euh.. why the sapphire?
What special property does it have, that it is needed for the inside of the big plate?
He wanted to "Trek" it out with some transparent aluminum.
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#1466 by rq3 on 12 Oct, 2016 14:01
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Looks like saphire has better thermal conductivity than quartz.
W/(m x K) at 300K:
Saphire: 23.1 parallel to optical axis, 25.2 perpendicular to optical axis
Quartz: 9.5 & 6.10
There are many materials that have better thermal conductivity than quartz. So why sapphire, since it cannot enter into the operation of the device other than add expense. Since Roger has finally seen fit to phase lock the exciter to the cavity, the phase locked loop will correct for any thermal perturbation of the large end. It could be constructed of copper, or even silver if thermal conductivity is important. And it IS important, since the substrate must keep the YBCO cool enough to superconduct.
The catadioptric small end (if that is indeed what it is) is a fascinating twist, too. Some nasty diamond turning under CNC will likely be needed to fabricate that! The whole thing looks like a "look what I could do if only I had the funding" effort.
I eagerly await peer reviewed thrust results while battery powered under hard vacuum (<1.0x10-6 torr). -
#1467 by rq3 on 12 Oct, 2016 14:06
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Good points rq3, but the mismatches on the Sapphire lattice depend on how the Sapphire and YCBO are bonded. Remember chips are made SoS (Silicone on Sapphire)from the patent :
He got the Helical antenna right on. (one a NSFer did for me by 3D printing July 2015)Quote"a single crystal sapphire substrate is glued to the major end plate..."
Euh.. why the sapphire?
What special property does it have, that it is needed for the inside of the big plate?
Saphire is a great thermal conductor and has a High dielectric constant (9.39 from 1.0 MHz to 8.5 GHz) a nice pick.
Shell
But according to the patent application, the sapphire is strictly a substrate for the superconductor. It never sees the EM field due to the YBCO film. If the idea was to have a thermally stable substrate, quartz would have been a better (and certainly less expensive) choice. Additionally, the lattice mismatch between single crystal sapphire (Al2O3) and YBCO is pretty severe. Not a good choice.
http://www.mt-berlin.com/frames_cryst/descriptions/sapphire.htm
My company extensively researched SOS and other uses for Sapphire as we were separating the dies with our equipment (10x faster than sawing or scribing). Even found a 100mm sapphire wafer we die separated on my old file system. (attached)
SOME chips are silicon on sapphire, IF the lattice match is correct. YBCO is basically a sintered ceramic. It's a real beast to get it to match to anything, let alone Al2O3. -
#1468 by Flyby on 12 Oct, 2016 14:08
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Just noticed the dual cavity setup to achieve "constant thrust"...
So basically, if I'm allowed for some humor, this is the electromagnetic version of a pulsejet, using 2 alternating pulsed EMdrives?
a Buzzbomb mark III ?
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#1469 by TheTraveller on 12 Oct, 2016 14:11
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Interesting stats:
http://flyhalo.com/parajet-paramotors-volution-custom-line-up/
ParaJet backpack motor thrust: 50kg (500N)
EmDrive with specific force 500N/kW would need 1kW of Rf to drive the ParaGlider. A small Lithium Ion battery pack could easily provide the energy for many hours of silent fight. Plus of course a small tank of liquid Nitrogen to cool the big end plate of the EmDrive thruster.
I did hang gliding years ago and would be eager to put on a ParaJet EmDrive back pack and go for a fly.
Of course not a space drive but could easily become one.
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#1470 by francesco nicoli on 12 Oct, 2016 14:11
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Looks like saphire has better thermal conductivity than quartz.
W/(m x K) at 300K:
Saphire: 23.1 parallel to optical axis, 25.2 perpendicular to optical axis
Quartz: 9.5 & 6.10
There are many materials that have better thermal conductivity than quartz. So why sapphire, since it cannot enter into the operation of the device other than add expense. Since Roger has finally seen fit to phase lock the exciter to the cavity, the phase locked loop will correct for any thermal perturbation of the large end. It could be constructed of copper, or even silver if thermal conductivity is important. And it IS important, since the substrate must keep the YBCO cool enough to superconduct.
The catadioptric small end (if that is indeed what it is) is a fascinating twist, too. Some nasty diamond turning under CNC will likely be needed to fabricate that! The whole thing looks like a "look what I could do if only I had the funding" effort.
I eagerly await peer reviewed thrust results while battery powered under hard vacuum (<1.0x10-6 torr).
pointed to that "it 'd work if only I'd funding" few minutes ago, but nobody noticed
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#1471 by TheTraveller on 12 Oct, 2016 14:12
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Just noticed the dual cavity setup to achieve "constant thrust"...
So basically, if I'm allowed for some humor, this is the electromagnetic version of a pulsejet, using 2 alternating pulsed EMdrives?
a Buzzbomb mark III ?
All of Roger's cryo designs used multiple EmDrive, driven by short Rf pulses. So nothing new here. -
#1472 by TheTraveller on 12 Oct, 2016 14:18
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The whole thing looks like a "look what I could do if only I had the funding" effort.
I eagerly await peer reviewed thrust results while battery powered under hard vacuum (<1.0x10-6 torr).
You missed the Universal Propulsion Ltd JV with Gilo Industries? Plenty of money there.
I suspect this EmDrive was built some time ago as to me the design screams this is a real device. Also suspect this IP is removed from any IP SPR shared with Boeing. -
#1473 by Monomorphic on 12 Oct, 2016 14:27
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This is making my brain hurt.
I may actually need some caffeine to get this modeled correctly.
"The shape of the minor end plate (curve FAH) is designed to ensure that the outer and axial path lengths EF, BA and JH are equal. In addition, any path length, represented by DG in figure 2 must also be equal to the outer and axial path lengths. This geometry is ensured by calculating the value of the machining radius CG of the curve FAH for any angle represented by GCA. This calculation is carried out by a numerical analysis in which the machining radius CG is iterated for steps in the angle GCA until the path length DG is equal to the outer and axial path lengths EF, BA and JH. The resulting curve shape FGA is shown in figure 3, where a typical result of such an analysis is given. A mirror image of this curve gives the curve AH and thus the complete concave shape of the minor end plate can be machined."
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#1474 by Tellmeagain on 12 Oct, 2016 14:35
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There are many materials that have better thermal conductivity than quartz. So why sapphire, since it cannot enter into the operation of the device other than add expense. Since Roger has finally seen fit to phase lock the exciter to the cavity, the phase locked loop will correct for any thermal perturbation of the large end. It could be constructed of copper, or even silver if thermal conductivity is important. And it IS important, since the substrate must keep the YBCO cool enough to superconduct.
The catadioptric small end (if that is indeed what it is) is a fascinating twist, too. Some nasty diamond turning under CNC will likely be needed to fabricate that! The whole thing looks like a "look what I could do if only I had the funding" effort.
I eagerly await peer reviewed thrust results while battery powered under hard vacuum (<1.0x10-6 torr).
pointed to that "it 'd work if only I'd funding" few minutes ago, but nobody noticed
Snipped. I do not want to involve in arguments. -
#1475 by TheTraveller on 12 Oct, 2016 14:43
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This is making my brain hurt.
I may actually need some caffeine to get this modeled correctly.
"The shape of the minor end plate (curve FAH) is designed to ensure that the outer and axial path lengths EF, BA and JH are equal. In addition, any path length, represented by DG in figure 2 must also be equal to the outer and axial path lengths. This geometry is ensured by calculating the value of the machining radius CG of the curve FAH for any angle represented by GCA. This calculation is carried out by a numerical analysis in which the machining radius CG is iterated for steps in the angle GCA until the path length DG is equal to the outer and axial path lengths EF, BA and JH. The resulting curve shape FGA is shown in figure 3, where a typical result of such an analysis is given. A mirror image of this curve gives the curve AH and thus the complete concave shape of the minor end plate can be machined."
I would assume the mode is still TE01x as we still need to eliminate eddy currents that flow from end plate to side wall. Please note the small end plate does move back and forth to retune the cavity to accelerative doppler shifts in the dual travelling waves. Likewise the big end plate attaches to the side wall and as in the small end plate, there should not be any eddy currents flowing across the physical joint from the superconducting big end plate to the side walls. -
#1476 by TheTraveller on 12 Oct, 2016 14:47
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There are many materials that have better thermal conductivity than quartz. So why sapphire, since it cannot enter into the operation of the device other than add expense. Since Roger has finally seen fit to phase lock the exciter to the cavity, the phase locked loop will correct for any thermal perturbation of the large end. It could be constructed of copper, or even silver if thermal conductivity is important. And it IS important, since the substrate must keep the YBCO cool enough to superconduct.
The catadioptric small end (if that is indeed what it is) is a fascinating twist, too. Some nasty diamond turning under CNC will likely be needed to fabricate that! The whole thing looks like a "look what I could do if only I had the funding" effort.
I eagerly await peer reviewed thrust results while battery powered under hard vacuum (<1.0x10-6 torr).
pointed to that "it 'd work if only I'd funding" few minutes ago, but nobody noticed
It is sad to see Mr. Shawyer to shift from honest mistake to aligning himself to Cannae.
So this new patent and the new JV makes you feel threatened that Roger and his JV partner will bring a flying EmDrive to the market? -
#1477 by meberbs on 12 Oct, 2016 15:01
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FEKO can compute the resonant freq of a frustum in say TE013 mode.
Physical definition of guide wavelength in a waveguide is the distance between surfaces of constant phase. In a resonating cavity this definition does not apply, because the entire volume has the same phase. What you have provided, yet again is a method of calculating, without defining what you are calculating.
Excel modeling the frystum as a large number of small length connected cylinder sections yields the guide wavelength for each section per the excited mode & freq. Integrating them yields the average guide wavelength for the frustum. Then for say TE013 mode, calculating the resonance agrees very closely to the FEKO value thus showing using conventional microwave waveguide theory can be used to calculate guide wavelength at any point of the frustum.
As for the resonance calculation, you have given an approximate method, but that does not mean that it is exact.The drop in EmWave momentum from the big to small end is not linear, so you can't just add up the axial side wall forces plus small end plate force and assume it equals big end plate force.
Who said the force on the sidewalls was linear?
It is actually quite complicated as shown by Egan here. And this shows it is not just an assumption, they really do add up to 0.
And I know all of your complaints about that derivation, none of which are valid. So before you start on that, provide a frustum shape that experimentally does not resonate where those equations predict. Alternatively, provide a set of dimensions (with spherical end plates) and I can run the numbers and show that it matches with FEKO.BTW with a constant diameter waveguide, such as used by Cullen, how can there be axial side wall forces that caused the reduction in end plate radiation pressure? What Cullen discovered was the end plate radiation pressure drops as per (external wavelength / guide wavelength) * conventional radiation pressure equation.
Why would there be axial side wall forces? the momentum is not changing as it propagates down the waveguide. Depending on the injection method, there would be forces on the antenna or waveguide entrance that bends the path of some of the energy to match the waveguide constraint, and possibly reflections as well.
At this site you can see diagrams of how the light in a waveguide effectively is superimposed waves travelling at angles and continually reflecting off the walls. Since the momentum not parallel to the primary direction of travel, the apparent momentum is less, although if you measured it (which would be a very difficult experiment), you would see the non-axial momentum in show up as forces on the sidewalls. (of course, this force is normal to the walls. If you picture something similar for the emDrive, it is clear how reflections from the angled sidewalls would change the amount of axial momentum in the photons, but at the same time generate an axial force component on the sidewalls. Also, the amount of axial momentum change obviously changes as you approach the small end, because the angle of reflection will be different due the the previous reflections.Here is a thought experiment for you. Take a resonant frustum, extend each end with a 1/4 wave length extension that matches the frustum end diameter, has constant diameter and has an end plate. Would you agree that the radiation pressure at end end plate should agree with Cullen's equations?
Possibly true, but nowhere near trivial to show, since the change in boundary conditions could cause some additional energy to be reflected before entering the straight section, and would certainly change the resonance frequency.Would you agree that Cullen's equation will not show a linear decrease in end plate radiation as the diameter is altered?
Again, this is irrelevant, I never claimed the force on the sidewalls was linear.
None of this changes that even if you ignore the force on the sidewalls, you are rejecting F=M*a by claiming the cavity will move in the opposite direction of the applied force.
Why is it so hard for you to accept that Shawyer's theory is inconsistent with both itself and with his own experiments? -
#1478 by TheTraveller on 12 Oct, 2016 15:17
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Why is it so hard for you to accept that Shawyer's theory is inconsistent with both itself and with his own experiments?
Well that is the issue because it is not.
BTW it is possible to measure both the thrust force (small to big) generated by the radiation pressure difference and then using a different test setup to measure the reaction force (big to small) generated to oppose the differential radiation pressure generated (small to big) thrust force.
So you see the physical experimental data matches what Roger's theory says should be generated. Plus experimental rotary table acceleration data shows constant acceleration with constant input power.
Which basically says what you believe to be correct theory is not. -
#1479 by meberbs on 12 Oct, 2016 15:23
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You ignored most of my post. Please start at the beginning, where I asked a question that is kind of important to understanding what you are talking about.Here's a thought experiment:
Consider a horizontal cylinder of length L, in free space, zero-g.
At each end of the cylinder is a mass M, which is large compared to the mass of the cylinder.
The mass on the left is firmly fixed to the end of the cylinder.
The mass on the right starts at the far right, but is free to float around in the cylinder.
If no external forces act on the system, the only force will be the gravitational attraction between the two masses. After a time, the two masses will accelerate toward each other, and eventually both will be in contact at the left end of the cylinder. Assuming the CM did not move... From the outside, it appears that the cylinder has accelerated and moved a distance L/2 to the right. Then stops, when the two masses meet and their momentum cancels out.
Consider the possibility that after some time, the movable mass M is dissipated as heat, into a heatsink on the left. Imagine a battery that feeds in a new mass M on the right side that is free to move in the cylinder. This is possible when using electromagnetic mass and it's momentum when injected is irrelevant. It just adds to the total mass.
http://www.feynmanlectures.caltech.edu/II_28.html
REPEAT ad nausea...
Momentum is conserved. Energy is conserved, and there is no propellant coming out the back except heat. It uses gravity to move itself. No fancy stuff, just gravitational attraction of one mass toward another, and a loss of mass though random heat exchange. Who disagrees with this and why?
Todd
What do you mean "no propellant coming out the back except heat"? Heat is a property of matter, not a substance. Do you mean thermal radiation? To dissipate the entire mass as radiation, you would need half of it to be antimatter, and if you directed that energy straight out the back you would get a lot of momentum out of it, enough to be moving at a fraction of light speed I believe.
The step where a battery feeds in a new mass sounds like magic to me. Where does this new mass come from? If it is coming from the battery, then the battery must start with mass greater than M and it loses mass M in creating that mass. And assuming the battery is attached to the cylinder to begin with you then have to go back and redo the original calculations accounting for that, and don't forget to add in the effect of moving that mass around as well.
I am not sure why you posted that link, but it talks about several subtle concepts, and has some intermediate conclusions that it later explains the issues with. Anything short of reading the whole thing will give you an incorrect impression. My attempt to summarize the conclusion of it is that mass of fundamental particles that are charged is in part due to the electromagnetic potential energy, but not entirely, and we don't know if there is a way to tell the difference or if it matters. (The specifics are more subtle than this, but you have to read the whole thing to get it.) Nothing in it changes what I said above about the mass having to already be in the mass of the battery, if the battery creates the mass.
Okay, so replace battery with a Solar Panel of negligible mass.
Do you understand a Capacitor gains weight when it is charged? If so, an Electric field contributes to its inertial mass. The EM Drive uses the inertial mass of the EM field inside it.
Anyway, adding enough energy through a solar panel (Assuming uniform illumination, and a panel that wraps around the object so there is no net momentum added, and that the cylinder is now at rest, so you don't have to worry about its velocity changing do to the added mass). This would be an absurd amount of energy to generate meaningful mass, and would be more effective to channel it into a laser pointed out the back.
For the capacitor gaining weight as it is charged, that has to do with E = mc^2 and the additional potential energy in the electrons adds to their mass. The fields themselves don't have inertial mass. Their is no distinguishable difference of the electromagnetically derived portion of an electrons mass from the rest of it, this is part of the conclusion from that link you posted.
So to illustrate what you seem to be saying in a simpler example (because there is nothing special about the electromagnetic mass), It is like saying after the initial motion, someone external to the system pulls out the movable mass (through a slot in the side or something) and then inserts a new one on the other side. (or just moves the original one forward, because why not) This effective work done by the external person is meaningful. And if you want this to be useful, you have to explain where all of this mass is coming from, and if energy is being moved internally, you are also shifting mass, because E = mc^2 (and even massless particles still have momentum, so shifting them isn't free either.)
I may actually need some caffeine to get this modeled correctly.