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#1500
by
TheTraveller
on 12 Oct, 2016 18:14
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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."
The lower image curve and the CG radius distance vs angle should give us what we need to determine the other dimensions.
BTW the centre and the side wall edge radius CA & CF are the same at 266.76mm
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#1501
by
Bob012345
on 12 Oct, 2016 18:39
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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.
Your system may work but the extra energy that you consider to be free may indeed be free to you but it comes at the expense of something else. It's coming from the reduction of kinetic energy of the exhaust of the system, whatever form that takes. Think of it like a transducer that use a small amount of energy to separate and rearrange two bigger piles of energy. In physics language, you are breaking a symmetry. Universally, energy and momentum are both conserved. A waterfall is "free" energy too. You are basically creating an energy waterfall.
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#1502
by
as58
on 12 Oct, 2016 18:57
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Your system may work but the extra energy that you consider to be free may indeed be free to you but it comes at the expense of something else. It's coming from the reduction of kinetic energy of the exhaust of the system, whatever form that takes. Think of it like a transducer that use a small amount of energy to separate and rearrange two bigger piles of energy. In physics language, you are breaking a symmetry. Universally, energy and momentum are both conserved. A waterfall is "free" energy too. You are basically creating an energy waterfall.
So you're saying that EMDrive works around conservation laws by interacting with... something. Well, that is hard to refute. I find the explanation that in fact EMDrive doesn't work a lot more plausible, but to each his own.
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#1503
by
TheTraveller
on 12 Oct, 2016 19:00
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I find the explanation that in fact EMDrive doesn't work a lot more plausible, but to each his own.
Well it does work as you will soon see when the EW paper is released. So not believing is not a simple fix way out.
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#1504
by
wicoe
on 12 Oct, 2016 19:06
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I find the explanation that in fact EMDrive doesn't work a lot more plausible, but to each his own.
Well it does work as you will soon see when the EW paper is released. So not believing is not a simple fix way out.
OK, let me try to rephrase... I find the explanation that "the apparent thrust observed in the tests that have been conducted so far is attributed to some natural error factor that has not yet been taken into account properly" a lot more plausible.
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#1505
by
Bob012345
on 12 Oct, 2016 19:07
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That would be saying that the final kinetic energy must always be equal to the chemical energy content delivered by the fuel and no more. Is that your position?
Actually, less: the final kinetic energy of the rocket equals the chemical energy delivered by the fuel burnt less the total kinetic energy gained by the propellant, and less the energy lost as waste heat.
Totally exact.
Bob012345, you can try to give a counter example 
It is well known that the upper stage of a rocket can gain more energy that the total energy content of its fuel.
That's because the fuel already has kinetic energy, often far greater than the chemical energy of the fuel. This is a known fact rocket engineers use.
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#1506
by
Bob012345
on 12 Oct, 2016 19:11
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I find the explanation that in fact EMDrive doesn't work a lot more plausible, but to each his own.
Well it does work as you will soon see when the EW paper is released. So not believing is not a simple fix way out.
OK, let me try to rephrase... I find the explanation that "the apparent thrust observed in the tests that have been conducted so far is attributed to some natural error factor that has not yet been taken into account properly" a lot more plausible.
Fine but that's just an opinion that shouldn't be given the same weight as the hard experimental data.
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#1507
by
wicoe
on 12 Oct, 2016 19:12
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It is well known that the upper stage of a rocket can gain more energy that the total energy content of its fuel.
That's because the fuel already has kinetic energy, often far greater than the chemical energy of the fuel. This is a known fact rocket engineers use.
Nope. For upper stage, the "final kinetic energy equals the chemical energy delivered by the fuel burnt less the total kinetic energy gained by the propellant, and less the energy lost as waste heat" formula is still true. You just need to take into account that the "total kinetic energy gained by the propellant" will be negative since it will be losing kinetic energy instead of gaining it (the upper stage is "slowing down" the propellant, thus reducing its kinetic energy).
This has nothing to do with the upper stage specifically, but with choosing a different inertial reference frame for calculations. If you choose a frame that is moving at a high speed relative to the rocket when the fuel starts burning (let's say it's moving in the opposite direction), the propellant will already have a lot of kinetic energy. However, once the fuel starts burning, the rocket will start gaining kinetic energy, but the propellant will start losing kinetic energy. If you run the math, the result is the same in any inertial frame.
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#1508
by
Space Ghost 1962
on 12 Oct, 2016 19:13
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Doesn't matter if something appears to work and isn't explained as to how it works. Something is there.
However, until one can prove what things work to the degree that they do ... conclusively, through all attempts to disclaim ... the discussion remains open as to the net meaning of it. Incomplete at best, totally false at worst.
So its wrong to both dismiss as it is to accept at this time.
Everyone wants to rush to conclusions. You can't.
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#1509
by
Bob012345
on 12 Oct, 2016 19:15
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Your system may work but the extra energy that you consider to be free may indeed be free to you but it comes at the expense of something else. It's coming from the reduction of kinetic energy of the exhaust of the system, whatever form that takes. Think of it like a transducer that use a small amount of energy to separate and rearrange two bigger piles of energy. In physics language, you are breaking a symmetry. Universally, energy and momentum are both conserved. A waterfall is "free" energy too. You are basically creating an energy waterfall.
So you're saying that EMDrive works around conservation laws by interacting with... something. Well, that is hard to refute. I find the explanation that in fact EMDrive doesn't work a lot more plausible, but to each his own.
Remember that if it conserves momentum, it also conserves energy. By assuming momentum conservation we can do energy calculations without knowing the precise mechanism. The momentum carried by the "exhaust" is always the momentum gained by the ship and kinetic energy is borrowed from the "exhaust" to conserve energy in all frames.
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#1510
by
wicoe
on 12 Oct, 2016 19:16
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Fine but that's just an opinion that shouldn't be given the same weight as the hard experimental data.
Extraordinary claims require extraordinary evidence... the experimental data is not there yet. How do you know the "effect" is not somehow related to Earth's gravity? Or to lorentz forces created by the EM fields around the cavity? This does not look like hard experimental data to me... just yet. But I agree in principle - "hard experimental data" may change everything.
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#1511
by
Star One
on 12 Oct, 2016 19:20
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Fine but that's just an opinion that shouldn't be given the same weight as the hard experimental data.
Extraordinary claims require extraordinary evidence... the experimental data is not there yet. How do you know the "effect" is not somehow related to Earth's gravity? Or to lorentz forces created by the EM fields around the cavity? This does not look like hard experimental data to me... just yet. But I agree in principle - "hard experimental data" may change everything.
Hard experimental data trumps all theoretical speculation. If the effect does exist but cannot be explained then that's the theorists problem not the experimenters.
Extraordinary claims require extraordinary evidence is one of the most over-used statements and one that is wheeled out far to often and often to defend overly entrenched positions.
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#1512
by
Monomorphic
on 12 Oct, 2016 19:25
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About to run some sims. I suspect the antenna location is important, so I put it at BA/3*2 as with the other TE013 cavities. In this case BA=25cm I had to build the circularization antenna from scratch.
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#1513
by
Bob012345
on 12 Oct, 2016 19:26
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Fine but that's just an opinion that shouldn't be given the same weight as the hard experimental data.
Extraordinary claims require extraordinary evidence... the experimental data is not there yet. How do you know the "effect" is not somehow related to Earth's gravity? Or to lorentz forces created by the EM fields around the cavity? This does not look like hard experimental data to me... just yet. But I agree in principle - "hard experimental data" may change everything.
Not true, dispute Carl Sagan's famous statement. It requires the same caliber of evidence to prove anything. It's a matter of prejudice as to what constitute extraordinary or not. Besides, that quote is often used by skeptics like a hammer to end debate. It sounds true but in reality is a poor metric.
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#1514
by
Star One
on 12 Oct, 2016 19:30
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Fine but that's just an opinion that shouldn't be given the same weight as the hard experimental data.
Extraordinary claims require extraordinary evidence... the experimental data is not there yet. How do you know the "effect" is not somehow related to Earth's gravity? Or to lorentz forces created by the EM fields around the cavity? This does not look like hard experimental data to me... just yet. But I agree in principle - "hard experimental data" may change everything.
Not true, dispute Carl Sagan's famous statement. It requires the same caliber of evidence to prove anything. It's a matter of prejudice as to what constitute extraordinary or not. Besides, that quote is often used by skeptics like a hammer to end debate. It sounds true but in reality is a poor metric.
Absolutely agree. It's usually more to try and defend a pre-existing belief rather than being open to new suggestions.
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#1515
by
Bob012345
on 12 Oct, 2016 19:34
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It is well known that the upper stage of a rocket can gain more energy that the total energy content of its fuel.
That's because the fuel already has kinetic energy, often far greater than the chemical energy of the fuel. This is a known fact rocket engineers use.
Nope. For upper stage, the "final kinetic energy equals the chemical energy delivered by the fuel burnt less the total kinetic energy gained by the propellant, and less the energy lost as waste heat" formula is still true. You just need to take into account that the "total kinetic energy gained by the propellant" will be negative since it will be losing kinetic energy instead of gaining it (the upper stage is "slowing down" the propellant, thus reducing its kinetic energy).
This has nothing to do with the upper stage specifically, but with choosing a different inertial reference frame for calculations. If you choose a frame that is moving at a high speed relative to the rocket when the fuel starts burning (let's say it's moving in the opposite direction), the propellant will already have a lot of kinetic energy. However, once the fuel starts burning, the rocket will start gaining kinetic energy, but the propellant will start losing kinetic energy. If you run the math, the result is the same in any inertial frame.
You are just repeating what I explained and adding a 'Nope' at the start. I got the concept from rocket experts quoted on Wikipedia so you can go argue with them.
What I said is still exactly true.
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#1516
by
Space Ghost 1962
on 12 Oct, 2016 19:37
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Fine but that's just an opinion that shouldn't be given the same weight as the hard experimental data.
Extraordinary claims require extraordinary evidence... the experimental data is not there yet. How do you know the "effect" is not somehow related to Earth's gravity? Or to lorentz forces created by the EM fields around the cavity? This does not look like hard experimental data to me... just yet. But I agree in principle - "hard experimental data" may change everything.
Not true, dispute Carl Sagan's famous statement. It requires the same caliber of evidence to prove anything. It's a matter of prejudice as to what constitute extraordinary or not. Besides, that quote is often used by skeptics like a hammer to end debate. It sounds true but in reality is a poor metric.
Clarity here.
One always holds an open mind to potential explanations. Where the "same calibre of evidence" is used to prove.
Conclusions are a different matter. They require multiple proofs from multiple different approaches. Otherwise it is too easy to have a systematic error conspire to support a false conclusion.
Which is why with Einstein "frame dragging" effects, we've had hundreds of different ways to confirm the effect. Expect even more in the future. It is a measure of the confidence in a correct conclusion that we keep on challenging things, long after there's a supportable conclusion.
That is an example of "extraordinary evidence".
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#1517
by
wicoe
on 12 Oct, 2016 19:41
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You are just repeating what I explained and adding a 'Nope' at the start. I got the concept from rocket experts quoted on Wikipedia so you can go argue with them.
What I said is still exactly true.
OK, so how is the "upper stage" argument relevant? No matter how you twist it, you're not getting more kinetic energy than the total chemical energy burnt, you're getting less. The amount of chemical energy it took for the 1st stage to accelerate this propellant is enormous. The upper stage is in a sense "stealing" from that already accelerated propellant (it's not if you change the ref frame to one co-moving with the upper stage at the moment of separation). You need to accelerate something first before you can start "stealing" kinetic energy from it.
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#1518
by
Bob012345
on 12 Oct, 2016 19:45
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#1519
by
TheTraveller
on 12 Oct, 2016 19:54
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from the patent :
"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 got the Helical antenna right on. (one a NSFer did for me by 3D printing July 2015)
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.
Did some Googling:
"YBCO thin films on sapphire substrates"
Seems this arrangement is common for microwave high power space applications. So it is a good choice.
