... Following this idea, could we imagine an "applied-field EmDrive" with an external belt coil that would produce a more powerful magnetic field inside the cavity, tuned to combine with the E-field (axial B-field in the case of TE modes, and toroidal B-field for TM modes) in order to enhance the Poynting vector in a preferred direction? Or is my idea coming from magnetohydrodynamics a complete nonsense when applied to standing waves in a resonant cavity?
Quote from: frobnicat on 06/15/2015 12:18 amActually the cross-correlation looks interesting, there is a relatively clear max (magnitude) centered around 0. Interestingly this absolute max is found at a lag of 3 frames (is it 3 minutes ?). I've been thinking more about this, we expect the em drive to produce thrust instantly, if there is a delay that means the thrust producing mechanism is most likely related to heat or another means. Because of this lag I'm leaning towards the thrust not being from a novel mechanism. We'll need more data to be sure.
Actually the cross-correlation looks interesting, there is a relatively clear max (magnitude) centered around 0. Interestingly this absolute max is found at a lag of 3 frames (is it 3 minutes ?).
...Has anyone else noticed that the cavity axis is not aligned exactly tangentially?
Hello,I'm new to this forum and want to add to the discussion:Thrust can be achieved by various error sources interacting with the environment as many out here already pointed out. eagleworks and many others used only small input power therefore i propose a test theory which is built on a pressure gradient caused by thermal effects. Explanation:The measured forces are tiny but divided by the projected area in thrust direction it becomes an even smaller pressure needed for thrust. Example for eagleworks tests: Area: 0.0613116 m² Force~0.05mN => Pressure needed=0.815mPa =0.00000008% of ambient pressure. Note that this is such a tiny pressure change that it could still be produced in near vacuum. My theory now is that this tiny pressure difference is caused by uneven heating in near wall regions (p=RTrho). Other reasons could be vibrations and magnetic fields. This effect should fairly quickly reach a constant thrust. If this theory holds up we should see a correlation between mode shape and thrust. The node shape dictates where heating occurs. All needed to test this is therefore to integrate heat production over the surfaces and add these up with respect to the orientation of said surface since the pressure gradient should be linear to this. It would probably suffice to use the B field on the boundary as an estimate for the heat production. My prediction is that certain frequencies will produce a heating pattern that is more uneven and hence produces more thrust. With all the reference geometries we have we might see a correlation to the data. If the math has already been done i'd like to apologize.
... IMO, the frustum "should" exert thrust ONLY when charging or discharging. It's should not work when it's at equilibrium with a constant Q value, no matter how high it is. ...
I've updated my Theory on the Wiki.http://emdrive.wiki/Todd_Desiato_(@WarpTech)%27s_Evanescent_Wave_Theory#Application_of_Theory_to_the_EmDriveThe EM Drive is intentionally designed to have asymmetrical attenuation. As such, energy is reflected from the large end to be stored at the small end as induced currents. Standing waves store energy and as such, store mass. As the EM drive charges and the Q ramps up, energy from the input source is reflected from the large end and stored in the small end on each successive reflection cycle. This energy is stored as induction currents caused by the near-field effects of evanescent waves. Due to the phase shift, the Power Factor is not zero as it is with standing waves. Therefore, work can be done to move the EM Drive. This dynamic action of storing mass-energy toward the front causes the center of mass to walk forward. The increasing pressure on the small end causes the EM Drive to accelerate forward due to the internal pressure gradient, until the pressure is equalized. Then the cycle builds again. This dynamic implies that a high Q value is not required, but rather how quickly can energy be ramped up under extreme attenuation conditions.Todd
Quote from: WarpTech on 06/16/2015 03:43 amI've updated my Theory on the Wiki.http://emdrive.wiki/Todd_Desiato_(@WarpTech)%27s_Evanescent_Wave_Theory#Application_of_Theory_to_the_EmDrive...Todd, to help unpack this a bit, when I read "energy stored as induction currents" I think of heating the fustrum - which would be inefficient since we want kinetic not thermal effects....
I've updated my Theory on the Wiki.http://emdrive.wiki/Todd_Desiato_(@WarpTech)%27s_Evanescent_Wave_Theory#Application_of_Theory_to_the_EmDrive...
So effectively a high Q system would be more inefficient because there would be more opportunity for the stored energy to leak out as heat. A high attenuation system like Yang's would be more efficient since the energy is not sitting around as long. Is this synopsis accurate from your perspective? Thanks!
Quote from: demofsky on 06/16/2015 04:08 amQuote from: WarpTech on 06/16/2015 03:43 amI've updated my Theory on the Wiki.http://emdrive.wiki/Todd_Desiato_(@WarpTech)%27s_Evanescent_Wave_Theory#Application_of_Theory_to_the_EmDrive...Todd, to help unpack this a bit, when I read "energy stored as induction currents" I think of heating the fustrum - which would be inefficient since we want kinetic not thermal effects....Correct...QuoteSo effectively a high Q system would be more inefficient because there would be more opportunity for the stored energy to leak out as heat. A high attenuation system like Yang's would be more efficient since the energy is not sitting around as long. Is this synopsis accurate from your perspective? Thanks!Sounds about right. If it were superconducting, it would be more efficient and the "loss per cycle" of the Q would be lost as thrust rather than heat. It's not necessary to have a high Q, it is necessary to have a high rate of charging and discharging, F = v*dm/dt, rather than m*dv/dt.My conjecture is that because it is the charging that walks the center of mass forward, microwaves and standing waves are not even needed. Just exponentially increasing or decreasing current densities, i.e., near field effects.Todd
It looks like CHAOTIC motion to meAnother day, another Baby EM Drive experiment, cavity direction is inverted compared to the previous test.I wonder why they are still using water instead of oil to dampen the motion. How difficult is it to get oil in Germany?I wonder why don't they instead go back to their first experiment in magnetic levitation but do it under a partial vacuum this timehttps://hackaday.io/project/5596-em-drive/log/19598-torsion-test-3-8-hours
Where are the thruster ON times indicated ?
And most of all, I wonder why don't they instead go back to their first experiment in magnetic levitation but do it under a partial vacuum this time.
https://hackaday.io/project/5596-em-drive/log/19598-torsion-test-3-8-hours
Quote from: Rodal on 06/16/2015 11:38 amAnd most of all, I wonder why don't they instead go back to their first experiment in magnetic levitation but do it under a partial vacuum this time.From an engineering point of view, I'd say components would be damaged due to internal pressure, maybe not to the point of blowing up, but definitely in a significant way. I'm thinking mostly of the batteries, but it could also be that the radar module they're using has non-vacuum-resistant capacitors.This is the problem EW had too, if I remember correctly; they had to purchase new vacuum-resistant components.Still, I concur that the floating setup seems more controllable and precise compared to this:Quotehttps://hackaday.io/project/5596-em-drive/log/19598-torsion-test-3-8-hoursLooking at the photos I'm not entirely surprised about the resulting noise levels.
I look at it this way and correct me if I'm wrong. The EM Drive could be thought of like this. You are trapped in an enclosed tank with a fire extinguisher and you turn on the fire extinguisher expecting it to move the tank, it doesn't because it's a enclosed system, but if you run up the side of the tank changing the local enclosed gravity profile of the tank, then you can move it in the direction you are running. And you haven't violated any laws just changed the local enclosed profile.Shell
Quote from: WarpTech on 06/16/2015 03:43 amI've updated my Theory on the Wiki.http://emdrive.wiki/Todd_Desiato_(@WarpTech)%27s_Evanescent_Wave_Theory#Application_of_Theory_to_the_EmDriveThe EM Drive is intentionally designed to have asymmetrical attenuation. As such, energy is reflected from the large end to be stored at the small end as induced currents. Standing waves store energy and as such, store mass. As the EM drive charges and the Q ramps up, energy from the input source is reflected from the large end and stored in the small end on each successive reflection cycle. This energy is stored as induction currents caused by the near-field effects of evanescent waves. Due to the phase shift, the Power Factor is not zero as it is with standing waves. Therefore, work can be done to move the EM Drive. This dynamic action of storing mass-energy toward the front causes the center of mass to walk forward. The increasing pressure on the small end causes the EM Drive to accelerate forward due to the internal pressure gradient, until the pressure is equalized. Then the cycle builds again. This dynamic implies that a high Q value is not required, but rather how quickly can energy be ramped up under extreme attenuation conditions.ToddI look at it this way and correct me if I'm wrong. The EM Drive could be thought of like this. You are trapped in an enclosed tank with a fire extinguisher and you turn on the fire extinguisher expecting it to move the tank, it doesn't because it's a enclosed system, but if you run up the side of the tank changing the local enclosed gravity profile of the tank, then you can move it in the direction you are running. And you haven't violated any laws just changed the local enclosed profile.Shell
Quote from: WarpTech on 06/16/2015 03:43 amI've updated my Theory on the Wiki.http://emdrive.wiki/Todd_Desiato_(@WarpTech)%27s_Evanescent_Wave_Theory#Application_of_Theory_to_the_EmDriveThe EM Drive is intentionally designed to have asymmetrical attenuation. As such, energy is reflected from the large end to be stored at the small end as induced currents. Standing waves store energy and as such, store mass. As the EM drive charges and the Q ramps up, energy from the input source is reflected from the large end and stored in the small end on each successive reflection cycle. This energy is stored as induction currents caused by the near-field effects of evanescent waves. Due to the phase shift, the Power Factor is not zero as it is with standing waves. Therefore, work can be done to move the EM Drive. This dynamic action of storing mass-energy toward the front causes the center of mass to walk forward. The increasing pressure on the small end causes the EM Drive to accelerate forward due to the internal pressure gradient, until the pressure is equalized. Then the cycle builds again. This dynamic implies that a high Q value is not required, but rather how quickly can energy be ramped up under extreme attenuation conditions.ToddGot to find some way that enough mass (or energy) leaks out (somehow) asymmetrically of the EM Drive to justify the claimed self-acceleration of its center of mass without breaking Conservation of Momentum. Either that, or you have to couple to an external directional field.