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#1480 by TheTraveller on 12 Oct, 2016 15:29
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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.
You really believe that? Bolding is mine. -
#1481 by meberbs on 12 Oct, 2016 15:35
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Others have covered issues with the rotary table.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.
Let me break this down as simple as possible:
1. Force on the large end of the cavity is pointed from the small end to the large end.
2. Force on the small end of the cavity is pointed from the large end to the small end.
3. Force on the large end of the cavity is larger than on the small end.
4. Therefore, the net force on the cavity it towards the large end (assuming no sidewall force)
5. Using only F=m*a, this means the cavity moves in the direction of the large end.
Specifically which of these points is wrong? 1-3 come from Shawyer, 4 is simply addition (i.e. -7+12 = 5) with the no sidewalls force assumption from Shawyer and 5 is F=m*a.
Shawyer's own experiments therefore disprove his theory. -
#1482 by flux_capacitor on 12 Oct, 2016 15:44
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I note five things in Shaywer's new patent that are blindingly obvious:
1- New end shapes: While the cavity is still a truncated cone, the big end plate is flat, undoubtedly because a crystal substrate and a superconducting film glued together are much easier to build as a flat surface instead of a spherical one, Shawyer claiming:Quote from: Roger ShawyerA cavity geometry which enables the major end plate to be flat, and thus simplifies the manufacturing process.
and the small end plate is spherically shaped. But instead of being convex (from the point of view of the frustum interior) like Shawyer's previous patents, Boeing's Flight Thruster or Tajmar's test cavity, so travelling waves are kept orthogonal to the side wall everywhere, the small end plate is concave, this time focusing waves towards the center of the big end plate. This inverted EM focusing shape may be some trade-off because of the cheaper and easier to build flat end plate. Shawyer writes:Quote from: Roger ShawyerA tapered, circular section, microwave cavity with a flat major end plate, whose concave shape is calculated to minimise the variation in path length across the waveform of the propagated electromagnetic wave. This shaped minor end plate and flat major end plate enable a high Q value to be achieved by minimising the phase distortion across the wavefront.
and:Quote from: Roger ShawyerA minor end plate with a curved shape such that the path length of the propagated wave within the thruster cavity is equal for all radial points on the wavefront.
[EDIT: same explanation from TheTraveller]
2- The thick single crystal sapphire substrate on the big flat end plate, with a thin YBCO superconducting thin film glued on top of it. What is its purpose? Is it there because it is a dielectric, or because it can hold the YBCO superconducting thin film in place and transfer the cold of the cooling cryogenic liquid to it? [EDIT: a clue from Monomorphic]
3- The thrust plate. Shawyer writes:Quote from: Roger ShawyerThe liquid gas cooler 7 is fixed to a thrust plate 11 via a thermal insulator 10. Thrust is generated in the direction of minor end plate towards major end plate and is transmitted to the spacecraft or airborne vehicle via the thrust plate 11. In the position shown in figure 1 the trust is therefore vertically downards, resulting in an acceleration of the spacecraft or airborne vehicle vertically upwards. This is a result of Newton's third law of motion.
This has already been debated many times but I still don't understand Shawyer's concept of "thrust". He always speak of thrust direction being opposite to the direction of acceleration, like the exhaust gas of a rocket, except in the EmDrive there is nothing ejected. This new "thrust plate" reminds me of a pop-up toy head with a spring mechanism hidden inside a box. If you are set upright a skateboard holding such a popup toy, and you decide to release the spring mechanism to let the head pop out of the box, you won't move. Even if you shout "NEWTON'S LAW!" when pressing the red button.
4- A helical circularly polarised input antenna mounted in the center axis near the small shaped end plate, as SeaShells pointed out.
5- Electrically asymmetric end conductors: the curved small end is non-superconducting, while the flat big end is superconducting. So Shawyer's newest partially superconducting EmDrive is in total contradiction with Todd's (WarpTech's) idea about maximising power dissipation at the big end and minimising it at the small end. According to his theory, Todd recommends to make the small end superconducting to prevent thermal loss, and the big end very thermally conductive, for example painting its exterior in black and covering it with heatsink fins. Something's gotta give.
I edited Shawyer's main drawing to add text captions to each number, attached.
[EDIT: So many post is so little time, I had to check back the three last pages to see if any of my questions has been answered in the meanwhile]
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#1483 by TheTraveller on 12 Oct, 2016 16:04
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This has already been debated many times but I still don't understand Shawyer's concept of "thrust".
Thrust is a force direction small to big
Reaction is a force direction big to small.
With the appropriate test setup, it is possible to measure both the primary Thrust force generated internally by the difference in the end plate radiation pressure and the Reaction force generated externally on the frustum in opposition to the internal Thrust force.
In the patent the internal Thrust force is down and the external Reaction force is up.
As attached.
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#1484 by flux_capacitor on 12 Oct, 2016 16:17
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TT, I understand the scheme, except thrust has to be something which is expelled out of the back of the vehicle and left behind. If you expel or transmit momentum to something that is attached to the vehicle, it won't move. I gave the example of the pop-up head toy on a skateboard, but you can take balls if you want: you can gently propel a boat if you throw many tennis balls towards the shore while being onboard, but it won't work with the attached ball of a jokari. Shawyer's thrust plate is the same as the attached ball of the jokari.
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#1485 by TheTraveller on 12 Oct, 2016 16:21
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Others have covered issues with the rotary table.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.
Let me break this down as simple as possible:
1. Force on the large end of the cavity is pointed from the small end to the large end.
2. Force on the small end of the cavity is pointed from the large end to the small end.
3. Force on the large end of the cavity is larger than on the small end.
4. Therefore, the net force on the cavity it towards the large end (assuming no sidewall force)
5. Using only F=m*a, this means the cavity moves in the direction of the large end.
Specifically which of these points is wrong? 1-3 come from Shawyer, 4 is simply addition (i.e. -7+12 = 5) with the no sidewalls force assumption from Shawyer and 5 is F=m*a.
Shawyer's own experiments therefore disprove his theory.
All forces have a "action force" and a matching equal but opposite "reaction force".
For the EmDrive, the Thrust force is the internal end plate differential "action force" (Small to Big) and the external Reaction force that accelerates the frustum is the opposite but equal "reaction force" (Big to Small). -
#1486 by TheTraveller on 12 Oct, 2016 16:25
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TT, I understand the scheme, except thrust has to be something which is expelled out of the back of the vehicle and left behind. If you expel or transmit momentum to something that is attached to the vehicle, it won't move. I gave the example of the pop-up head toy on a skateboard, but you can take balls if you want: you can gently propel a boat if you throw many tennis balls towards the shore while being onboard, but it won't work with the attached ball of a jokari. Shawyer's thrust plate is the same as the attached ball of the jokari.
The internal EmWave undergoes momentum change as the guide wavelength varies, caused by diameter change.
Nothing needs to be exhausted. This is a new way to exchange momentum between internal EmWave and the external frustum. The frustum gained momentum is sourced from the EmWave and causes it to red shift, reflecting its lower momentum and upon each end plate reflection to grow progressively longer.
In your ball example or the flashlight example, the momentum exchange at each end is the same, so there is no movement. However thanks to the changing waveguide diameter, the EmWave grows longer and shorter depending on where it is in the frustum. This is the special effect that most miss.
Imagine a ball bouncing from end to end and at the big end it had more momentum to transfer and at the small end it had less momentum to transfer. Ok that is outside most folks experience but it is what happens to the EmWave.
That end plate force differential is what Roger calls the Thrust force and with the right test setup it can be measured. However it will not accelerate a EmDrive as you can't have a one sided force and so the EmDrive moves in the opposite way as a equal but opposite Reaction force to the Thrust force.
Ok again this is outside the way we see the world but that does not mean it can't work like that.
As Roger says, the engineering principles behind the EmDrive have been known for 65 years.
From the patent:QuoteThrust is generated in the direction of minor end plate towards major end plate and is transmitted to the spacecraft or airborne vehicle via the thrust plate 11.
In the position shown in figure 1 the thrust is therefore vertically downwards, resulting in an acceleration of the spacecraft or airborne vehicle vertically upwards.
This reaction is a result of Newton's third law of motion.
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#1487 by WarpTech on 12 Oct, 2016 16:44
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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.)
Hey, don't be so serious! I don't do anything except make jokes before I have my morning coffee.
There's nothing worse that waking up grumpy in the morning.
1. I used heat as an example of a process where dissipation will produce random momentum vectors, such that there will be no NET momentum from the heat escaping. Antimatter is not required.
2. Posting the link to EM Mass, probably wasn't the best link to post. I disagree, where you say a source-free EM field has no mass. It has nothing to do with the mass of the electrons changing. The free field has no "rest" mass, but it possesses inertia and an equivalent inertial mass, and it can be attracted by gravity, otherwise light would not be bent when passing a massive star.
3. Regarding your last para. as a "simpler example". Imagine that after the two masses are in contact at the left end and the person outside has removed the mass through the side. That "like the EM Drive" there is no gravitational field outside the cylinder. Or, for example, we "switch off" the gravity of the mass on the left end. Then, the person on the outside is free to move the moveable mass back to the right without increasing it's relative potential energy. The amount of work required is not equal to what was gained previously. He can insert it back into the right-end of the cylinder and then "switch on" the gravity of the left mass to start the process over.
In the case of my EM Drive Theory, the g-field is only "inside" the frustum. it doesn't extend outside it because the frequency & bandwidth is too low to pass through the copper, unlike natural gravitational fields that have such high frequency and bandwidth that it passes right through matter. Therefore, rearranging mass outside the frustum has no potential energy to overcome. It's only after the mass is inside the frustum, that it "feels" the g-field.
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#1488 by Monomorphic on 12 Oct, 2016 16:53
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This new "Bell" shaped geometry is much more difficult to model than the concave-convex geometry. This is completely because of the iteration steps for the minor end plate shape. It turns out it is not a perfect spherical radius, but more pinched (parabolic) towards the top.
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#1489 by Bob012345 on 12 Oct, 2016 17:03
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I don't get your last paragraph. Even Shwayer talks about static forces in test rigs as well as non accelerating lifting devices for cars and lifting spacecraft to GEO. I think an EmDrive is like a rocket with an inexhaustible fuel source where the mass doesn't change.That is getting a bit old. There is no energy generation. Just a few folks here may need to adjust their frame reference to the EmDrive and forget what happens in other frames.
You see, CoE means that energy must be conserved in all inertial frames, not just in one specially chosen (and not even inertial) frame. Switching to a different inertial frame and running calculations is a common method of finding mistakes.
Tell that to the EmDrive as it only obeys A = F/M.
Maybe you can explain how all the various frame KE accountants will demand the EmDrive obeys their frame's KE calculations?
The EmDrive will use energy to do work on the ship's mass to generate the desired Dv to reach and dock with a distant destination. That all the other frame KE accountants will be upset matter not to the ship.
Would seem the universe has just flipped the bird at all the various KE frame accountants and said to them. Sorry guys but your understanding is limited and needs to change.
Roger told me he collected data from the Demonstrator rotary test rig and it proved there was no CofM nor CofE violation. I did ask him to publish that data, but so far it has not happened.
I do know of one other EmDrive rotary test but again the data is not publically available. When I finally get my next build together, I will publish the CofM and CofE energy balances as collected on the continually accelerating rotary test rig.
Bottom line is:
1) EmDrive does work
2) No CofM violation as the ships gained momentum is sources from the Em Wave's momentum as yes it is red shifted as a result.
3) No CofE violation in regard to the local frame as the drive obeys A = F/M.
Oh BTW you can't hook of a EmDrive to a generator as the generator runs at a fixed RPM, IE no increase in angular velocity = no angular acceleration = no angular acceleration = no EmDrive Force generated. To generate Force the EmDrive must accelerate. A EmDrive is NOT A ROCKET MOTOR. It does not act like a rocket motor. If it can't accelerate, there is no force generated. -
#1490 by SeeShells on 12 Oct, 2016 17:07
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I've always considered a phenomenon known as Lenz's Law (induced eddy currents) and evanescent wave actions to be a prime contender in the thrust anomaly. The magnetic fields induced (Lentz Law) in the metal of the sidewalls of the frustum creating counter EM fields, coupled with evanescent wave action decay could account for a thrust potential within the cavity and also make it a non-enclosed drive as energy can escape). They also can account for the Jerk actions seen by me and other DYIers even EW upto and including some Mach Effects. These actions within the drive would have to be pulsed driven to work more effectively.
When Dr. Montillet gave his skype presentation at the Advanced Propulsion Workshop I was excited someone else had seen some of the same actions I was thinking of and had the tools to put it to a theory on the EMD actions.
Anyone remember when I wanted to call my first build "Crazy Eddie Drive". Some thought it was for Crazy Eddie in the SciFi book "The Mote in God's Eye". It was for the Eddy currents TBH and a play on words.
My Best...
Shell
PS: I'm still digging through the math on this paper as it is a little above my pay grade, although you can always learn.QuoteMultiplicity of Solutions for Linear Partial
Di erential Equations Using (Generalized) Energy
Operators
September 11, 2015
J.-P. Montillet,
Conclusions
The core of this work is to de ne the notion of multiplicity of the solutions
of a linear PDE using the model associated with energy spaces and the (gen-
eralized) energy operators. In this way, it contradicts the classical way of
solving a nominated PDE with boundaries conditions, but it rather focuses
on additional solutions from these energy spaces. The multiplicity is de ned
through Theorem 2 and the Corollary 1. The work shows how the energy
operators (and generalized energy operators) can determine which energy
subspace is reduced to f0g.
The theory is then applied to the evanescent waves, a special type of solu-
tions of the wave equation. The last part with the closed waveguide shows
a possible real world application and opens some possible understanding of
what is happening in the EMD engine with the de nition of duplication of
waves. In this case, the duplication of waves is when additional solutions
should be taken into account due to the level of energy increasing in the cav-
ity. However, this work remains at a theoretical level and more work with
simulations are required to fully understand the concept of duplication.
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#1491 by Bob012345 on 12 Oct, 2016 17:16
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The question makes perfect sense but one needs to assume a power for the battery. If it's drained at 300kw it can last 3333 seconds which is the same for all observers. The forces 1000N and the acceleration is 1 m/s^2 so and the final velocity is 3.333km/s. This is the same for any assumed power drain but the time will be longer or shorter. Note that simply equating the 1E9J to kinetic energy in the starting frame gives only 1.41km/s. This shows the apparent CoE violation we are debating.
Ok. But what if we harvest 50% of the kinetic energy (with some engineering solution that I will here handwave away), use 1.5 GJ of that more than 2 GJ to recharge the battery to 1 GJ (that extra 50% is to account for inefficiencies) and repeat. What, if anything, stops us from doing that?
Then you'd get there slower. You're just borrowing energy from the "propellant" and using it to charge your battery at the expense of a much slower trip. Summing up all energies would still yield the input energy.
I'm not going anywhere, I'm trying to generate free energy. My scheme would give more than 0.5 GJ per iteration.
I know you are trying to prove the EmDrive doesn't work with this thought experiment but I assume you are thinking of a rotating device? -
#1492 by TheTraveller on 12 Oct, 2016 17:25
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I don't get your last paragraph. Even Shwayer talks about static forces in test rigs as well as non accelerating lifting devices for cars and lifting spacecraft to GEO. I think an EmDrive is like a rocket with an inexhaustible fuel source where the mass doesn't change.That is getting a bit old. There is no energy generation. Just a few folks here may need to adjust their frame reference to the EmDrive and forget what happens in other frames.
You see, CoE means that energy must be conserved in all inertial frames, not just in one specially chosen (and not even inertial) frame. Switching to a different inertial frame and running calculations is a common method of finding mistakes.
Tell that to the EmDrive as it only obeys A = F/M.
Maybe you can explain how all the various frame KE accountants will demand the EmDrive obeys their frame's KE calculations?
The EmDrive will use energy to do work on the ship's mass to generate the desired Dv to reach and dock with a distant destination. That all the other frame KE accountants will be upset matter not to the ship.
Would seem the universe has just flipped the bird at all the various KE frame accountants and said to them. Sorry guys but your understanding is limited and needs to change.
Roger told me he collected data from the Demonstrator rotary test rig and it proved there was no CofM nor CofE violation. I did ask him to publish that data, but so far it has not happened.
I do know of one other EmDrive rotary test but again the data is not publically available. When I finally get my next build together, I will publish the CofM and CofE energy balances as collected on the continually accelerating rotary test rig.
Bottom line is:
1) EmDrive does work
2) No CofM violation as the ships gained momentum is sources from the Em Wave's momentum as yes it is red shifted as a result.
3) No CofE violation in regard to the local frame as the drive obeys A = F/M.
Oh BTW you can't hook of a EmDrive to a generator as the generator runs at a fixed RPM, IE no increase in angular velocity = no angular acceleration = no angular acceleration = no EmDrive Force generated. To generate Force the EmDrive must accelerate. A EmDrive is NOT A ROCKET MOTOR. It does not act like a rocket motor. If it can't accelerate, there is no force generated.
Static Force measurement is of the primary end plate radiation pressure derived Thrust force. The only way to measure the equal but opposite Reaction force that I know of requires the EmDrive to be able to freely accelerate.
Levitation requires acceleration of the levitated mass at 1g. So even though it may not move, to the EmDrive it is accelerating the mass at 1g.
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#1493 by TheTraveller on 12 Oct, 2016 17:30
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This new "Bell" shaped geometry is much more difficult to model than the concave-convex geometry. This is completely because of the iteration steps for the minor end plate shape. It turns out it is not a perfect spherical radius, but more pinched (parabolic) towards the top.
The small end plate shape corrects the phase distortion introduced by the simple and low cost to make flat end plate. It works like a distortion correction lens or reflector in an optical system.
I'll be impressed if FEKO can model this frustum. -
#1494 by WarpTech on 12 Oct, 2016 17:30
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This new "Bell" shaped geometry is much more difficult to model than the concave-convex geometry. This is completely because of the iteration steps for the minor end plate shape. It turns out it is not a perfect spherical radius, but more pinched (parabolic) towards the top.
Ah! Parabolic is what it's supposed to be! I was always perplexed why he used spherical. For instance, we use a parabolic antenna dish, not spherical antenna dish to maximize signal strength.
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#1495 by TheTraveller on 12 Oct, 2016 17:44
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This new "Bell" shaped geometry is much more difficult to model than the concave-convex geometry. This is completely because of the iteration steps for the minor end plate shape. It turns out it is not a perfect spherical radius, but more pinched (parabolic) towards the top.
Ah! Parabolic is what it's supposed to be! I was always perplexed why he used spherical. For instance, we use a parabolic antenna dish, not spherical antenna dish to maximize signal strength.
Roger used spherical end plates, as in that frustum configuration the travelling waves have a spherical wave front, which to reflect with no phase distortion, requires the reflecting surface to be spherical to match that of the incoming wave.
I doubt the small end plate curve is a parabola. -
#1496 by Bob012345 on 12 Oct, 2016 17:45
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Again you refuse to accept the experimental data.
What experimental data am I ignoring? There have been no conclusive results shared.Inside a waveguide, EmWave momentum varies as the guide wavelength varies as Cullen proved in 1950. As diameter reduces, guide wavelength increases and momentum decreases. In a resonant cavity end plate radiation pressure increases as Q and power increase. In a frustum a momentum gradient is established being highest at the big end and smallest at the small end. This gradient generates an internal force toward the big end. The frustum moves toward the small end as a balancing reaction force.
First, Cullen did not work with waveguides that vary diameter, and it is not trivial to extend that work, especially since the emDrive is a tapered cavity, not a cylindrical waveguide. You have repeatedly failed to even provide a physical definition of guide wavelength for this case when asked.
Second, assuming that the momentum in the fields does change along the length, this would have to happen due to interactions with the side walls. These forces on the sidewalls balance the difference in forces on the end plates. There obviously are forces on the sidewalls, because otherwise, you wouldn't need them to contain the radiation between the plates. Ignoring the sidewall forces and saying the momentum in the fields magically changes with no interactions breaks conservation of momentum by definition.
Third, even ignoring the balancing force on the sidewalls, you then said that there would be a force towards the big end. This is the force the EM fields exert on the end plate, and is the "correct" result if you blindly apply Cullen's equations and ignore the sidewall forces. This means that the drive should move towards the big end because that is the direction of the force applied to it. The "reaction" statement you made makes no sense. Based on that statement, then if I push an object to the left, then I would expect it to react by moving to the right, and that is not how things work. All I am doing here is applying F=M*a, but you seem to want F = - M*a.
Have you pre-decided that the NASA results upcoming in December are not real evidence? -
#1497 by as58 on 12 Oct, 2016 17:48
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The question makes perfect sense but one needs to assume a power for the battery. If it's drained at 300kw it can last 3333 seconds which is the same for all observers. The forces 1000N and the acceleration is 1 m/s^2 so and the final velocity is 3.333km/s. This is the same for any assumed power drain but the time will be longer or shorter. Note that simply equating the 1E9J to kinetic energy in the starting frame gives only 1.41km/s. This shows the apparent CoE violation we are debating.
Ok. But what if we harvest 50% of the kinetic energy (with some engineering solution that I will here handwave away), use 1.5 GJ of that more than 2 GJ to recharge the battery to 1 GJ (that extra 50% is to account for inefficiencies) and repeat. What, if anything, stops us from doing that?
Then you'd get there slower. You're just borrowing energy from the "propellant" and using it to charge your battery at the expense of a much slower trip. Summing up all energies would still yield the input energy.
I'm not going anywhere, I'm trying to generate free energy. My scheme would give more than 0.5 GJ per iteration.
I know you are trying to prove the EmDrive doesn't work with this thought experiment but I assume you are thinking of a rotating device?
Not necessarily. I could just accelerate in straight line until the battery is empty and then break to a standstill (in the original reference frame where the device started at rest), harvesting a part of the kinetic energy during braking so that I'd get enough energy to recharge the battery and some extra. -
#1498 by wicoe on 12 Oct, 2016 18:03
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That end plate force differential is what Roger calls the Thrust force and with the right test setup it can be measured. However it will not accelerate a EmDrive as you can't have a one sided force and so the EmDrive moves in the opposite way as a equal but opposite Reaction force to the Thrust force.
Ok again this is outside the way we see the world but that does not mean it can't work like that.
Well, I can't help but wonder, why go with an "explanation" that really is "outside the way we see the world" as opposed to a number of alternative explanations that aren't? -
#1499 by Monomorphic on 12 Oct, 2016 18:05
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I doubt the small end plate curve is a parabola.
If you follow this you get a curve that is not a perfect radius:
"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."
There's nothing worse that waking up grumpy in the morning. 