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#3100 by ThinkerX on 24 Feb, 2016 04:29
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About the blowing your own sail video and why it got my wheels turning about EmDrive. I'm not sure if this makes sense yet. I've been working on the "secondary" which is the matter in the frustum. (Side note, I'm feeling kind of dumb for dumping the non-conservative electric field and going straight to the non-conservative gravitoelectric field. I'll save the gravity stuff for extra credit. The importance of the curl came to me in the wrong order.)
Here's what I have rattling around. I was thinking about the relationship between heat and kinetic energy. http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/kintem.html
A molecule incident on the sail, after the inelastic collision, gives some momentum to the sail and gives up heat. The molecule after collision is slower and colder.
Now enter the EmDrive, same concept with a cavity wall being the sail. The cavity walls have a cold side (outside) and a hot side. After all the electromagnetic, quantum gravity, non-conservative yada yada business is over, at the end of the day it's starting (we'll see) to look like to me that the EmDrive is just a heat engine. It doesn't seem to work when there's no "stuff" in the cavity.
So can all this thrust be explained by thermodynamics? I know from Eagleworks thermal camera pics that the temperature is not uniform across the cavity.
Is anyone here really good with thermodynamics stuff? It's not my thing.
So in that case, what's causing the 'thrust' is the excitation of the 'air' molecules inside the cavity. (Maybe they're being 'herded' somehow by the EM fields?)
Vacuum tests, far fewer molecules, hence far less 'thrust.'
But can this excitation of molecules produce 'thrust' comparable to that claimed for EM tests? To me, it seems like photon rocket levels of movement.
Assuming a pressurized frustum, would this device move in space? And would the pressurized environment degrade over time and need replacing? I note that thrust 'falls off' after a time in these tests - maybe that has to do with the internal atmosphere (molecules) becoming...changed? depleted?
And from the video, it seems different types of molecules excite at radically different rates.
Real screwy thought: these are microwave oven magnetrons (well, mostly) that people are playing with. They tend to heat whatever is in the microwave (food) and not the shell, (not so much anyhow). With the EM Drive, the only other thing in the frustum besides electromagnetic energy is air. So maybe it's heating (turbocharging) the air molecules making weird things happen, not just at the molecular level, but the subatomic one as well.
Screwball conclusion: an unpressurized EM Drive in space (vacuum) probably will not work. A pressurized one might. But that still leaves us with CoE and CoM issues...right? -
#3101 by oliverio on 24 Feb, 2016 06:22
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I have often entertained the idea that the EMDrive may be something of a coherent flow-generator of spacetime; that is to say, if some sort of superfluidic theory of spacetime is true, one ought to be able to get this "blow on your own sail" effect from the right sort of vortex action (like particular modes that we know of, notably TEO12?)
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#3102 by CW on 24 Feb, 2016 08:22
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Hmm.. I was wondering, if there is a way for a relative power missmatch to occur at the smaller and larger endplate (caused by the area difference), and if that power missmatch could be a way to transfer the energy delta into kinetic energy of the EM-drive. Just throwing my 2 cents in the air here.
EDIT:
It is known for e.g. pipes, that a flowing fluid accelerates from a larger inner cross section towards a smaller inner pipe cross section. Is there a known equivalent phenomenon, that can happen in a conductor for, say, electrons flowing through a wire from a larger diameter to a smaller diameter? The one thing that changes is the current density, which involves heating the wire more in smaller cross sections. In the hollow EM-drive inner volume, there are obviously no electrons flowing freely, but the mode creates a back and forth of energy flow. I wonder if this 'wiggling' energy field ever so slightly pushes against one preferred end plate, depending on the mode chosen. -
#3103 by dustinthewind on 24 Feb, 2016 08:32
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I'm curious about the heat related discussions creating unaccounted for thrust errors.
How much of the RF is being converted into heating the frustrum? Preferably described in watts.
I am wondering why there hasn't been a discussion of placing a heating coil of the appropriate size inside a frustrum and directly measuring the effects. I realize such a measurement would not take into account the Lorentz forces of a powered on Maggie, but at least that should give a handle on how heating affects the particular setup being measured. That would include the effects of beam lengthening, hot air currents, hot air lift on the top lip etc.
Am I missing something here?
I greatly admire what this group is doing. I also have read every post in 6 threads. I'd like to say I understood all that I read, but .....
Induction heating in the cavity isn't exactly the same as a heating coil heating the cavity. The induction currents (that keep light inside) will make a pattern of heat in the cavity (via resistance) that will differ from a heating coil. However, it can be predicted using the finite element analysis for a static mode what heating should be seen. FDTD can take a long time to reach equilibrium, but is not static in time. It's possible FDTD could give clues to some heating pattern induced by some transforming mode but I'm not so sure that a transforming mode wouldn't just be the cavity reaching its maximum potential for stored energy. I think NASA saw in their thermal camera the mode shape they were expecting to see on the cavity, but I am not sure if the temperature matched the predicted values. -
#3104 by Mulletron on 24 Feb, 2016 09:50
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@ThinkerX yeah so without fail, no matter what kind of wonky rabbit hole I go down, I always end up back here http://arxiv.org/pdf/1104.5011.pdf
Action reaction symmetry is broken but momentum is still conserved. -
#3105 by CW on 24 Feb, 2016 10:04
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@ThinkerX yeah so without fail, no matter what kind of wonky rabbit hole I go down, I always end up back here http://arxiv.org/pdf/1104.5011.pdf
Action reaction symmetry is broken but momentum is still conserved.
I have a hunch, too, that the specific entropy distribution within the frustum could be a part of the mystery. -
#3106 by Lar on 24 Feb, 2016 11:53
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LENR is off topic. Even if you try to couch it in "process". Trimmed.
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#3107 by Rodal on 24 Feb, 2016 12:06
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Thermal engine is possible since we are still early in the game. Recall discussions about the pioneer anomaly and its thermal causes. Thought there might be a link several threads ago...never followed up on it. Got too busy planning and building test stand and first unit.
No, it is not "in the game" as a competitive, efficient form of space propulsion. Thermal engine and "discussions about the pioneer anomaly" may be only "in the game" to explain the EM Drive as due to experimental artifacts conducted in air.
As I have explained previously, in space you cannot have heat transfer by conduction or by convection (because there is no external air), you can only release heat in space by radiation, which means emitting photons, mostly in the infrared frequency (which means low energy photons compared to higher frequency photons). The Stefan–Boltzmann law.
(One could release heat by ejecting mass that contains heat, but one of the main claims of the EM Drive is that it is a closed system that is not ejecting any mass, a "propellant-less engine" since ejecting mass would mean a conventional rocket)
Early on I put together the Experimental Results table in the wiki as a comparison with a perfectly collimated photon rocket. What makes the claims by Shawyer and Yang so outlandish is that they claim force/power several orders of magnitude larger than a perfectly collimated photon rocket (over 300,000 times in the case of Yang).
Ejecting heat into space by radiation constitutes a form of space propulsion even more inefficient than a perfectly collimated photon rocket. It is horribly inefficient.
As previously discussed, modeling of the Pioneer anomaly by JPL confirms the extremely small force/power of relying on heat radiation: it is lower than the force/power of a perfectly collimated photon rocket.
So the only way that <<Thermal engine is possible since we are still early in the game>> would be to explain the EM Drive is as an experimental artifact for EM Drive experiments conducted in air.
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#3108 by Rodal on 24 Feb, 2016 12:16
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I'm curious about the heat related discussions creating unaccounted for thrust errors.
How much of the RF is being converted into heating the frustrum? Preferably described in watts.
I am wondering why there hasn't been a discussion of placing a heating coil of the appropriate size inside a frustrum and directly measuring the effects. I realize such a measurement would not take into account the Lorentz forces of a powered on Maggie, but at least that should give a handle on how heating affects the particular setup being measured. That would include the effects of beam lengthening, hot air currents, hot air lift on the top lip etc.
Am I missing something here?
I greatly admire what this group is doing. I also have read every post in 6 threads. I'd like to say I understood all that I read, but .....
Welcome to the thread
<<placing a heating coil of the appropriate size inside a frustrum and directly measuring the effects. >> has been previously discussed several times in the past.
Actually, the last series of tests reported by Prof. Yang on the EM Drive, before she reportedly retired because funding of her EM Drive project was cancelled, involved heating of the EM Drive and reporting the temperature vs time, using embedded thermocouples.
Concerning <<Am I missing something here?>>, one can extract conclusions as to "why" discussions often devolve into such extremely unlikely things as "warping of spacetime" by a magnetron found in millions of home kitchen microwaves instead of discussing <<placing a heating coil of the appropriate size inside a frustrum and directly measuring the effects>> the first one engages the mind into science fiction dreams, while the second one deals with bringing us back from the dream, back into reality. It is much more fascinating to discuss the extremely unlikely spacetime warping than to discuss how "the anomalous force" may be just due to experimental artifacts.
What attracts most readers to this thread is discussion of some form of electromagnetic propellant-less space propulsion (whether it can be done with the EM Drive as presently conceived or by some other concept), and there is less interest in discussing the EM Drive experiments as being due to experimental artifacts: as an inefficient heater
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#3109 by Monomorphic on 24 Feb, 2016 15:03
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By revolving the frustum and extending along the central axis, I was able to create a helical frustum with curved end-plates. This geometry is ideal for recycling photons without causing interference and seems like a viable way to "stack" emdrives and still only use one RF source. Can't wait to get it into FEKO.
Here is the model in sketchfab so you can orbit and zoom:https://skfb.ly/L97F
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#3110 by rfmwguy on 24 Feb, 2016 15:14
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Here are the latest and greatest simulations I've made:
any feedback is welcome!
Solidworks tour coming soon...
Hoping we have time to build it before we graduate!
Great tour Kurt! One question I have is on the spherical end...will be interesting to experiment with that. Do you have the center small diameter plate as the focal point? Any concerns on small diameter cutoff?
p.s. Hope you keep your trail-blazing mentality throughout your career. This is what will separate you from the crowd...well done. -
#3111 by rfmwguy on 24 Feb, 2016 15:25
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You and others might be surprised, but I am still open for this possibility. While my observational tests lead me to believe in the emdrive effect, I still consider what I saw on my own experiment to possibly be thermal (even tho I think its a small possibility).Thermal engine is possible since we are still early in the game. Recall discussions about the pioneer anomaly and its thermal causes. Thought there might be a link several threads ago...never followed up on it. Got too busy planning and building test stand and first unit.
(snip)
So the only way that <<Thermal engine is possible since we are still early in the game>> would be to explain the EM Drive is as an experimental artifact for EM Drive experiments conducted in air.
Got my Schlieren light source in yesterday. If I see displacement again with the new design, I'll get the mirrors to study the thermal plume. I guess we disagree, thermal is still in play with my own experimental efforts. -
#3112 by D_Dom on 24 Feb, 2016 17:06
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By revolving the frustum and extending along the central axis, I was able to create a helical frustum with curved end-plates. This geometry is ideal for recycling photons without causing interference and seems like a viable way to "stack" emdrives and still only use one RF source. Can't wait to get it into FEKO.
can't wait to fabricate one IRL. Guessing the flat pattern layout can be exported from sketchfab. Will start with a tried and true paper pattern. If FEKO results are promising and you start closing in on final dimensions I will fire up a sheetmetal roll and see what I can come up with. -
#3113 by zellerium on 24 Feb, 2016 19:05
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Here are the latest and greatest simulations I've made:
any feedback is welcome!
Solidworks tour coming soon...
Hoping we have time to build it before we graduate!
Great tour Kurt! One question I have is on the spherical end...will be interesting to experiment with that. Do you have the center small diameter plate as the focal point? Any concerns on small diameter cutoff?
p.s. Hope you keep your trail-blazing mentality throughout your career. This is what will separate you from the crowd...well done.
Thank you!
Both sperical end caps have their center point where the frustum's cone tip would be similar as in this picture:
The cutoff wavelength doesn't seem to impede the mode I've been going for so I'm not concerned with steady state operation, there will probably be some transient effect that I'm unaware of though.
Absolutely! I'm planning to continue the EM Drive pursuit in my spare time while working in VA next year, but I'll be doing night classes as well for my MS so I'm not sure how much time I'll have.
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#3114 by X_RaY on 24 Feb, 2016 19:28
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Yeah. Feko lite shows interesting field pattern.
The geometry is more or less random. Just a try.
Last file is a .gif of the H field over frequency.
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#3115 by zen-in on 24 Feb, 2016 19:28
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I have 3 big cavity filters, made from Copper, that could be used by someone to make a fustrum. There is a 2-3" Dia Copper tuning rod inside attached to a threaded invar rod. They are made from 20, possibly 18 gauge Copper. One has a dent in the side. They are 23" high by 10.75" Dia so there is one big sheet of Copper there that could be formed into a fustrum. The outside is powder coated. That would come off as the Copper is heated and worked.
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#3116 by Notsosureofit on 24 Feb, 2016 19:46
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FYI:
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.043902
Universal Nature of the Nonlinear Stage of Modulational Instability
ABSTRACT
We characterize the nonlinear stage of modulational instability (MI) by studying the longtime asymptotics of the focusing nonlinear Schrödinger (NLS) equation on the infinite line with initial conditions tending to constant values at infinity. Asymptotically in time, the spatial domain divides into three regions: a far left and a far right field, in which the solution is approximately equal to its initial value, and a central region in which the solution has oscillatory behavior described by slow modulations of the periodic traveling wave solutions of the focusing NLS equation. These results demonstrate that the asymptotic stage of MI is universal since the behavior of a large class of perturbations characterized by a continuous spectrum is described by the same asymptotic state. -
#3117 by SeeShells on 24 Feb, 2016 20:35
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By revolving the frustum and extending along the central axis, I was able to create a helical frustum with curved end-plates. This geometry is ideal for recycling photons without causing interference and seems like a viable way to "stack" emdrives and still only use one RF source. Can't wait to get it into FEKO.
Here is the model in sketchfab so you can orbit and zoom:https://skfb.ly/L97F
I dearly love this kind of layout and always have. What does my name tell you? It's why I picked the name here.
I'd like to see a frustum close to this layout.
Keep it up, love your work!
SeeShells
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=39004.0;attach=1101080;image
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#3118 by Rodal on 24 Feb, 2016 21:21
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By revolving the frustum and extending along the central axis, I was able to create a helical frustum with curved end-plates. This geometry is ideal for recycling photons without causing interference and seems like a viable way to "stack" emdrives and still only use one RF source. Can't wait to get it into FEKO.
It will be interesting to see what experiments will show, as it will serve to validate/invalidate theories of operation.
Here is the model in sketchfab so you can orbit and zoom:https://skfb.ly/L97F
According to my interpretation of Dr. White's QV theory, this torus design should be considerably worse than the frustum of a cone design (when comparing an equivalent frustum of a cone with similar outside dimensions).
The important thing is the Energy Density (for the QV theory and for other theories based on General Relativity, like Minotti's, Trunov, etc.).
For example, this is the Energy Density distribution for mode shape TE013:
This torus shape prevents the Energy Density from achieving its maximum at the inside core of the EM Drive, and instead it substitutes it for a thin ring on the outside periphery.
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#3119 by Notsosureofit on 24 Feb, 2016 21:41
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The important thing is the Energy Density (for the QV theory and for other theories based on General Relativity, like Minotti's, Trunov, etc.).
For example, this is the Energy Density distribution for mode shape TE013:
A good illustration of the energy distribution not being in the maximum entropy state.
