Author Topic: Propellantless Field Propulsion and application  (Read 1040400 times)

Offline john smith 19

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Re: Propellantless Field Propulsion and application
« Reply #1680 on: 11/10/2012 07:12 am »
Is it not EM drive with a cylindrical chamber, not a conical one?
"Tapered" cylindrical sounds like a synonym for conical to me.
Keep in mind this is not a free lunch drive. If you believe e=mc^2 and run with it the idea you end with something that can turn energy into thrust. The questions are a) Is this it an b) does this efficiency look reasonable.

Of course until this actually turns up as a peer reviewed article in Science, Nature or one of the other heavyweight journals (IE in English, because, after all, how can you trust anything from a culture that's only had writing for a couple of thousand years :)  ) this will not be taken seriously.

Or perhaps when the Chinese starting fitting them to a habitat and send it to Mars. That would be quite a wake up call.
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Offline KelvinZero

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Re: Propellantless Field Propulsion and application
« Reply #1681 on: 11/10/2012 08:27 am »
Keep in mind this is not a free lunch drive. If you believe e=mc^2 and run with it the idea you end with something that can turn energy into thrust. The questions are a) Is this it an b) does this efficiency look reasonable.

It really does promise free unlimited energy. Read my last post. I can expand on the math if you like but there is not much to it.

Just because it is a free lunch doesnt mean it is impossible. Perfectly sane physicists discuss entire universes appearing from quantum fluctuations. Perhaps something like this is exactly what we need to explain the fermi paradox also. Aliens never go anywhere, they just spew out their own matter, pushing the rest of the universe away in the process. It is possible, but way more significant than proponents seem to grasp.
« Last Edit: 11/10/2012 08:45 am by KelvinZero »

Offline john smith 19

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Re: Propellantless Field Propulsion and application
« Reply #1682 on: 11/10/2012 08:43 am »
It really does promise free unlimited energy. Read my last post. I can expand on the math if you like but there is not much to it.

Please do. Otherwise it comes across as a bald assertion.
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Offline KelvinZero

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Re: Propellantless Field Propulsion and application
« Reply #1683 on: 11/10/2012 09:17 am »
It really does promise free unlimited energy. Read my last post. I can expand on the math if you like but there is not much to it.

Please do. Otherwise it comes across as a bald assertion.

Ok, it wasn't meant to come across as an assertion but there really isnt much to the math. Numbers are just going to bulk it up.

Ok, from the article:
"720 mN from 2.5 kw of input power".
Now we are agreed that what this means is that for a constant input of power, we get a constant force right?

for argument's sake, lets assume we are using this to accelerate a 1kg mass. lets assume we accelerate the mass for five hours (18000 seconds).

How much energy have we expended in our drive?
expended energy
  = power * time
  = 2.5kw * 18000s
  = 45,000,000 joules

How much velocity have we gained? (note: force=mass*acceleration)
Velocity gained
  = acceleration * time
  = force/mass * time
  = 0.720n/1kg * 18000s
  = 12960 meters per second (almost 13km per second)

But now we have this very fast moving object we could of course generate electricity from it, say by decelerating it along a magnetic rail or something. It does not matter how. What matters is how much energy we could extract.

Kinetic energy is given by the well known formula:
Ek = 0.5mv^2
  = 0.5*1*(12960)^2
  = 83,980,800 joules.

This is about twice the energy you put in using the propellentless propulsion.

Really these numbers do not matter though. The key principle is that the drive lets you increase your velocity linearly with energy, but totally standard physics lets us extract energy out proportional to the square of the velocity.
It does not matter if their drive is only a millionth of this effectiveness.. at some point the linear power required will be less than the quadratic curve of the kinetic energy gained.
« Last Edit: 11/10/2012 10:39 am by KelvinZero »

Offline KelvinZero

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Re: Propellantless Field Propulsion and application
« Reply #1684 on: 11/10/2012 10:37 am »
By the way, two things we have today are not that far off propellentless propulsion: the propeller and the sail. Perhaps we could come up with a drive that pushes against solar wind or the interstellar medium. It could be interesting to get your head around the math of why these do not break any laws but could still be vastly more efficient than a rocket.

Offline mboeller

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Re: Propellantless Field Propulsion and application
« Reply #1685 on: 11/10/2012 10:49 am »
.......
This is about twice the energy you put in using the propellentless propulsion.

Really these numbers do not matter though. The key principle is that the drive lets you increase your velocity linearly with energy, but totally standard physics lets us extract energy out proportional to the square of the velocity.
It does not matter if their drive is only a millionth of this effectiveness.. at some point the linear power required will be less than the quadratic curve of the kinetic energy gained.

you know that this is not possible with a EM-Drive. If you have read the papers you would know that the performance falls off rather fast with an increase in velocity. An EM-Drive works only good perpendicular to the velocity vector.

Offline jded

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Re: Propellantless Field Propulsion and application
« Reply #1686 on: 11/10/2012 11:35 am »
.......
This is about twice the energy you put in using the propellentless propulsion.

Really these numbers do not matter though. The key principle is that the drive lets you increase your velocity linearly with energy, but totally standard physics lets us extract energy out proportional to the square of the velocity.
It does not matter if their drive is only a millionth of this effectiveness.. at some point the linear power required will be less than the quadratic curve of the kinetic energy gained.

you know that this is not possible with a EM-Drive. If you have read the papers you would know that the performance falls off rather fast with an increase in velocity. An EM-Drive works only good perpendicular to the velocity vector.

Performance falls with velocity relative to what? There is no such thing in physics as absolute velocity.

Offline JohnFornaro

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Re: Propellantless Field Propulsion and application
« Reply #1687 on: 11/10/2012 02:39 pm »
Is it not EM drive with a cylindrical chamber, not a conical one?
"Tapered" cylindrical sounds like a synonym for conical to me.

Scanned too fast; totally overlooked that.  The picture in the AvWeek article is of one of Shawyer's articles, if I'm not mistaken.  Note that the scientist would not take questions from AvWeek.

Ok, it wasn't meant to come across as an assertion but there really isnt much to the math. Numbers are just going to bulk it up.


Thanks for that easily readable explanation. 

Quote
Now we are agreed that what this means is that for a constant input of power, we get a constant force right?

Uh, yeah.  Pragmatically, I ask this question a lot:  Where does the power come from?  As I understand it, for this device to be useful, the 2.5 kW power supply has to fit in 1 kg total probe mass, correct?

.......
This is about twice the energy you put in using the propellentless propulsion.

... The key principle is that the drive lets you increase your velocity linearly with energy, but totally standard physics lets us extract energy out proportional to the square of the velocity.

It does not matter if their drive is only a millionth of this effectiveness... at some point the linear power required will be less than the quadratic curve of the kinetic energy gained.

you know that this is not possible with a EM-Drive. ... performance falls off rather fast with an increase in velocity. An EM-Drive works only good perpendicular to the velocity vector.

Performance falls with velocity relative to what? There is no such thing in physics as absolute velocity.

With velocity relative to the article being accelerated, presumably.  No need for a concept of absolute velocity AIUI.

But:

If you were out in the middle of space, no matter what you weighed, were you to apply
0.720 newtons of force, you would accelerate in the opposite direction.  If you wanted just to coast at a constant speed, you'd turn off your device.  After a given time, if you wanted to decelerate, you'd have to apply 0.720 newtons in the opposite direction.  All that energy expelled in starting and stopping is lost to entropy.  The benefit that you would have gained would be that you got from Point A to Point B, over a period of time X.

You can't get more energy out of the deceleration than you applied during the acceleration.

If you believe e=mc^2 and run with it the idea you end with something that can turn energy into thrust. The questions are a) Is this it ?

I do, and yeah, that is the question.  I believe that it should be theoretically possible to convert energy to momentum.  Of course, I have no idea how this would be done.  Paul March and Woodward, et al., believe that they can induce matter to vibrate in a preferential direction by correct application of electrical energy, but their efficiency at doing this is so low as to be virtually imperceptible from the matter's natural random vibration.

From the AvWeek article:

Quote
Shawyer's EmDrive does not have any exhaust. It consists of a tuned cavity shaped like a truncated cone into which resonating microwaves are channeled. Like other radiation, these exert a tiny pressure when reflected off a surface. According to Shawyer, the pressure exerted on the large end of the cavity is greater than the pressure on the small end, producing a net thrust.

This appears to be a violation the law of conservation of momentum. However, Shawyer says net thrust occurs because the microwaves have a group velocity (the velocity of a collection of electromagnetic waves) greater in one direction than the other and relativistic effects to modify the Newtonian mechanics.

Shawyer maintains that there is a causal relationship between the group velocity of a wave thru matter, and the actual momentum of the matter, and that he can manipulate it so that there is a preferential direction of momentum.  It appears to violate the conservation of momentum, according to people who have a better understanding of the principles than I do. 

The current thought is that there is no causal relationship between the group velocity of a wave thru matter, and the momentum of the matter thru which the wave travels, thus no work can be done by this process.
« Last Edit: 11/10/2012 04:12 pm by JohnFornaro »
Sometimes I just flat out don't get it.

Offline mboeller

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Re: Propellantless Field Propulsion and application
« Reply #1688 on: 11/10/2012 03:54 pm »
Performance falls with velocity relative to what? There is no such thing in physics as absolute velocity.

It does not matter what I believe but what is written in the papers about the EM-drive. See for example:  http://www.emdrive.com/theorypaper9-4.pdf  [page 9]


Offline ChileVerde

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Re: Propellantless Field Propulsion and application
« Reply #1689 on: 11/10/2012 05:04 pm »

Or perhaps when the Chinese starting fitting them to a habitat and send it to Mars. That would be quite a wake up call.

Boy, will they get a surprise.
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Offline QuantumG

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Re: Propellantless Field Propulsion and application
« Reply #1690 on: 11/10/2012 09:52 pm »
Performance falls with velocity relative to what? There is no such thing in physics as absolute velocity.

It does not matter what I believe but what is written in the papers about the EM-drive. See for example:  http://www.emdrive.com/theorypaper9-4.pdf  [page 9]

You do understand that these papers are nothing but gobbledegook, right? What's interesting here is that these Chinese researchers came up with their own theory for how it works, and that new theory is what allowed them to produce a drive that actually works (or so they say).

Now, if it turns out that all this drive does, if it works at all, is give you a terribly inefficient way to turn electrical energy into kinetic energy, leaving conservation of energy in-tact, then that's just not all that interesting from a practical standpoint.

Why? Well, you still need a lot of stored energy on-board your vehicle, or you need to receive beamed energy of some sort (such as solar power), which can be converted to electricity to be used. We already have engines that work in that mode, electric thrusters, and they're much more efficient than the numbers that are coming out of this research (if they're real).

Perhaps sometime in the future, if this technology ever becomes verified as real, the efficiency will go up. Until then, it's just a trade for the side-benefits (no propellant tank, no exhaust impingement concerns) against the worse efficiency.

Human spaceflight is basically just LARPing now.

Offline KelvinZero

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Re: Propellantless Field Propulsion and application
« Reply #1691 on: 11/11/2012 12:11 am »
.......
This is about twice the energy you put in using the propellentless propulsion.

Really these numbers do not matter though. The key principle is that the drive lets you increase your velocity linearly with energy, but totally standard physics lets us extract energy out proportional to the square of the velocity.
It does not matter if their drive is only a millionth of this effectiveness.. at some point the linear power required will be less than the quadratic curve of the kinetic energy gained.

you know that this is not possible with a EM-Drive. If you have read the papers you would know that the performance falls off rather fast with an increase in velocity. An EM-Drive works only good perpendicular to the velocity vector.

I don't know that, which isnt to say it isn't true. My entire argument rests on the assertion that for a constant power you can exert a constant force on your craft. If you understand that paper and it says something different, educate us!

The thing is, if the performance is dependent on anything other than the craft's current frame of reference, e.g. its performance is less when it is moving faster, then it is really important to define what you are moving faster with respect to.. otherwise you could turn on this device and it will suddenly drag you off towards Sagittarius at a hundred thousand km/s with no way back, because it turns out our galaxy is already going a fair clip within this arbitrary frame.

If on the other hand you are pushing against some sum of the entire universe that always appears stationary within your current frame, just as light always appears to be relative to your current frame, you end up with the same energy from nothing (or from the sum of the entire universe). I really don't see any particular reason to reject energy from nothing but accept propellentless propulsion. Why shouldnt we get both at once. In for a penny, in for a pound as they say ;)
« Last Edit: 11/11/2012 12:21 am by KelvinZero »

Offline 93143

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Re: Propellantless Field Propulsion and application
« Reply #1692 on: 11/11/2012 07:37 am »
If you were out in the middle of space, no matter what you weighed, were you to apply
0.720 newtons of force, you would accelerate in the opposite direction.  If you wanted just to coast at a constant speed, you'd turn off your device.  After a given time, if you wanted to decelerate, you'd have to apply 0.720 newtons in the opposite direction.  All that energy expelled in starting and stopping is lost to entropy.  The benefit that you would have gained would be that you got from Point A to Point B, over a period of time X.

You can't get more energy out of the deceleration than you applied during the acceleration.

Sure you can.  All you need to do is fly through an electromagnetic decelerator instead of using the thruster.  Then, as you come to a stop at the far end of the decelerator, you plug in and recharge your batteries.  If you were doing at least 6945/η m/s or so (where η is the efficiency of the decelerator/charger/battery system), you will be fully charged before the decelerator's caps run dry.

There are better ways; they involve rotation, which is a great way to move fast without going anywhere.  Even so, at the reported level of efficiency you do have to go pretty fast...

Quote
I believe that it should be theoretically possible to convert energy to momentum.

It's not.  They are two different things.

Now, if it turns out that all this drive does, if it works at all, is give you a terribly inefficient way to turn electrical energy into kinetic energy, leaving conservation of energy in-tact, then that's just not all that interesting from a practical standpoint.

Why? Well, you still need a lot of stored energy on-board your vehicle, or you need to receive beamed energy of some sort (such as solar power), which can be converted to electricity to be used.

You can't turn electrical energy into kinetic energy without throwing something away.  You have to have something to do work on, so it can do work on you in return; you can't do work on yourself.  This is blindingly obvious to anyone who understood high school physics.

A rocket produces constant thrust at constant power, regardless of how fast it's moving; the energy books balance because of the kinetic energy of the propellant, and the fact that you eventually run out of it.  The work is done on the propellant; from the perspective of the rocket, only the propellant ends up with any kinetic energy.

Cars have a thrust-to-power ratio that depends on velocity, because they do work on something in an external reference frame (ie: the road).

This device doesn't sound like its operating principle should depend on reference frame.  It might, if it's actually interacting with a local object like the Earth or the sun, or a lab magnet someone forgot was on the same circuit, or if it interacts with distant matter that's freakishly symmetric, or something like that...  Anyway, any device with a frame-independent thrust-to-power ratio, that doesn't throw anything out the back, can be induced to behave like a perpetual motion machine of the first kind.

That doesn't mean it is.  Mach effect seems to be, at worst, a perpetual motion machine of the second kind, since it does have something to push on and is thus capable of 'farming' energy from the rest of the universe when configured appropriately (thrusters on flywheel hooked to generator, for instance).  I'm not sure about this one...  I downloaded the paper, but it's in Chinese so I can't read it...

Quote
We already have engines that work in that mode, electric thrusters, and they're much more efficient than the numbers that are coming out of this research (if they're real).

Uh, no.  The thrust-to-power ratio in this case is 3472 W/N, which is equivalent to 708 seconds of Isp at 100% jet power efficiency, or 425 seconds at 60%.  Vastly more impulse per unit energy than an ion drive, and the disadvantage of such high specific thrust (namely high propellant consumption) is eliminated.  Solar electric and nuclear electric would both become far easier and more effective with a device like this.

If this is real (which I'm not taking a position on) it needs to be replicated ASAP, because it is huge.
« Last Edit: 11/12/2012 11:12 pm by 93143 »

Offline QuantumG

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Re: Propellantless Field Propulsion and application
« Reply #1693 on: 11/11/2012 11:56 am »
You can't turn electrical energy into kinetic energy without throwing something away.  You have to have something to do work on, so it can do work on you in return; you can't do work on yourself.  This is blindingly obvious to anyone who understood high school physics.

...

If this is real (which I'm not taking a position on) it needs to be replicated ASAP, because it is huge.

Congratulations catching up with the conversation. Perhaps you could try to not be insulting to those of us who are already here, next time?
Human spaceflight is basically just LARPing now.

Offline mboeller

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Re: Propellantless Field Propulsion and application
« Reply #1694 on: 11/11/2012 01:20 pm »

You do understand that these papers are nothing but gobbledegook, right?

Sure

Quote
What's interesting here is that these Chinese researchers came up with their own theory for how it works, and that new theory is what allowed them to produce a drive that actually works (or so they say).

Sorry but I cannot read Chinese so I cannot comment here.

Quote
Now, if it turns out that all this drive does, if it works at all, is give you a terribly inefficient way to turn electrical energy into kinetic energy, leaving conservation of energy in-tact, then that's just not all that interesting from a practical standpoint.

I don't think so. A ion drive with 2.5KW and 3000sec would, if my math is correct, at 75% efficiency only generate ~125mN instead of the reported 720mN (according to the aviation week article)

Offline JohnFornaro

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Re: Propellantless Field Propulsion and application
« Reply #1695 on: 11/11/2012 01:46 pm »
If you were out in the middle of space, no matter what you weighed, were you to apply
0.720 newtons of force, you would accelerate ... if you wanted to decelerate, you'd have to apply 0.720 newtons in the opposite direction.  All that energy expelled in starting and stopping is lost to entropy. 

You can't get more energy out of the deceleration than you applied during the acceleration.

Sure you can.  All you need to do is fly through an electromagnetic decelerator instead of using the thruster.

Is this not what the Prius does, when braking downhill?   And after your journey over hill and dale, don't you have to fill it up with gas again?  Because of entropy?

Quote
Then, as you come to a stop at the far end of the decelerator, you plug in and recharge your batteries.  IMCAC, if you were doing at least 6945/sqrt(η) m/s or so (where η is the efficiency of the decelerator/charger/battery system), you will be fully charged before the decelerator's caps run dry.

Isn't the efficiency term where entropy is factored in?

Quote
There are better ways; they involve rotation, which is a great way to move fast without going anywhere.  Even so, at the reported level of efficiency you do have to go pretty fast...

An electric motor rotates, so I get this.  But it doesn't go anywhere unless it pushes against something, which also can be done.  This is the operating principle of the Prius, which always runs out of gas, even though it never runs out of road. 

I don't get what point you are trying to make.

Quote from: JF
I believe that it should be theoretically possible to convert energy to momentum.

Quote from: 93143
It's not.  They are two different things.

That's what I thought, too.  Somebody tell me that my summary of the EM Drive, and the ME drive is incorrect:  You put electricity into it, and then it moves forward.  Note that I don't have the math to prove my belief; I only accept, and that tentatively, what is the topic of this thread: Conversion of energy to forward momentum.  I also don't seem to grasp how kinetic energy is apparently not related to momentum.

Quote from: 93143
You can't turn electrical energy into kinetic energy without throwing something away...

A rocket produces constant thrust at constant power, regardless of how fast it's moving...

Cars ... work on something in an external reference frame (ie: the road).

Go on...

Quote from: 93143
This device doesn't sound like its operating principle should depend on reference frame.  It might, if it's actually interacting with a local object like the Earth or the sun, or a lab magnet someone forgot was on the same circuit, or if it interacts with distant matter that's freakishly symmetric, or something like that...  Anyway, any device with a frame-independent thrust-to-power ratio, that doesn't throw anything out the back, can be induced to behave like a perpetual motion machine of the first kind.

That doesn't mean it is.  Mach effect seems to be, at worst, a perpetual motion machine of the second kind, since it does have something to push on and is thus capable of 'farming' energy from the rest of the universe when configured appropriately (thrusters on flywheel hooked to generator, for instance).  I'm not sure about this one...  I downloaded the paper, but it's in Chinese so I can't read it...

Woodward and all claim that the ME device pushes against the frame of rest of the universe, and state that they have derived a mathematical model which correctly restates the idea of action at a distance to support their thesis.   This math, I don't get.

Quote
The thrust-to-power ratio in this case is 3472 W/N, which is equivalent to ...

Which, believe it or not, I get.

Quote
If this is real (which I'm not taking a position on) it needs to be replicated ASAP, because it is huge.

Which is why this thread is so friggin' long, for one thing.
« Last Edit: 11/11/2012 02:45 pm by JohnFornaro »
Sometimes I just flat out don't get it.

Offline 93143

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Re: Propellantless Field Propulsion and application
« Reply #1696 on: 11/11/2012 09:38 pm »
You can't turn electrical energy into kinetic energy without throwing something away.  You have to have something to do work on, so it can do work on you in return; you can't do work on yourself.  This is blindingly obvious to anyone who understood high school physics.
Congratulations catching up with the conversation. Perhaps you could try to not be insulting to those of us who are already here, next time?

You said:

Now, if it turns out that all this drive does, if it works at all, is give you a terribly inefficient way to turn electrical energy into kinetic energy, leaving conservation of energy in-tact

What I get from this is that you're proposing that the device might allow velocity- and orientation-independent propellantless thrust but not locally-apparent free energy.

What I'm trying to point out is that this is fundamentally impossible for very basic physical reasons.  This has been made clear multiple times, not only on this thread but also on talk-polywell's M-E thread (as well as anywhere GoatGuy shows up, but unfortunately he seems to think that this makes M-E a conservation of energy violator), and my experience is that for some reason people have a bewildering amount of trouble grasping it...

Even if you didn't mean that, that's what it sounds like, and others could be misled.

You can't get more energy out of the deceleration than you applied during the acceleration.
Sure you can.  All you need to do is fly through an electromagnetic decelerator instead of using the thruster.
Is this not what the Prius does, when braking downhill?   And after your journey over hill and dale, don't you have to fill it up with gas again?  Because of entropy?

Partly because of entropy - that's why the gas engine isn't 100% efficient.  But even if it were, and if the electric motor operation and reclamative braking were 100% efficient, and the batteries didn't leak at all, and there were no frictional or air resistance or rolling resistance losses, you would still not end the journey with more stored energy than you had at the start.

This is because the energy required to produce a certain amount of thrust depends on the speed of the vehicle, so no matter how fast you go, it takes at least as much energy to get that fast as you can theoretically get by slowing back down.  Basic Newtonian mechanics.

The proposed thruster doesn't appear to have that limitation, which implies that its operating principle is something weird, that may lead to an entropy principle violation or even a conservation violation.

Quote
Isn't the efficiency term where entropy is factored in?

It's where entropy is generated.  But the Second Law of Thermodynamics provides no reason why η needs to be below unity in principle, because the described system is not a heat engine.  And there is certainly no fundamental physical reason η needs to be low enough to prevent local over-unity operation of the described system given an arbitrarily high vehicle speed.

Quote
Quote
There are better ways; they involve rotation...
I don't get what point you are trying to make.

Basically that the linear acceleration/deceleration system you and I described is monstrously impractical for energy generation, and a steady-state rotating system might be a better plan.

Quote from: JF
Somebody tell me that my summary of the EM Drive, and the ME drive is incorrect:  You put electricity into it, and then it moves forward.  Note that I don't have the math to prove my belief; I only accept, and that tentatively, what is the topic of this thread: Conversion of energy to forward momentum.  I also don't seem to grasp how kinetic energy is apparently not related to momentum.

Basically this:

Quote from: 93143
You can't turn electrical energy into kinetic energy without throwing something away...

You have to push on something, and it can't be yourself.  Newton's Third Law.  All of this discussion turns on that.

Cars push on the road.  Rockets push on their propellant.  M-E thrusters (if they work) push on the rest of the observable universe, but since their behaviour seems to be independent of velocity or at least orientation this has some interesting theoretical consequences.  It isn't yet clear what this EM-Drive is supposed to push on.

Also, both momentum and kinetic energy are frame-dependent, but to different powers, while other forms of energy are not frame-dependent.  This messes naïve attempts at equivalence right the #### up.

...

Energy being the capacity to do work, it might make more sense to consider kinetic energy not as inherent in the velocity of a moving object, but rather as inherent in the difference in velocities between two objects.  If everything is moving at the same velocity, there's no capacity to do work involved no matter what reference frame you pick.
« Last Edit: 11/11/2012 10:37 pm by 93143 »

Offline 93143

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Re: Propellantless Field Propulsion and application
« Reply #1697 on: 11/11/2012 10:15 pm »
Actually, that bears repeating.

Kinetic energy is frame-dependent.  Electrical energy is not.

Anyone still having trouble should think about that for a bit.

Offline 93143

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Re: Propellantless Field Propulsion and application
« Reply #1698 on: 11/11/2012 10:35 pm »
« Last Edit: 11/11/2012 10:47 pm by 93143 »

Offline QuantumG

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Re: Propellantless Field Propulsion and application
« Reply #1699 on: 11/11/2012 11:00 pm »
We all know this already. Do you think we're slow or something?

The claim has been made, by both Roger Shawyer and these Chinese researchers, that this device violates conservation of momentum, using electrical power as the input.

The question is, if this device works, does that necessarily mean conservation of energy is also violated? I, and others, say it does whereas some say it doesn't, but can't explain in any consistent way why it doesn't.

Now, if you care to participate in the conversation without being condescending, please do, otherwise go insulting people elsewhere.
Human spaceflight is basically just LARPing now.

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