Quote from: frobnicat on 06/06/2015 05:04 pmQuote from: Rodal on 06/06/2015 04:40 pmLet's discuss this on objective basis, not on what Higgins writes or having a poll on why people have suspicions. It doesn't matter really if most people are more familiar with conservation of energy than conservation of momentum. Nature has its own laws.You yourself said that a CoE issue is a CoM issue and reciprocally (if relativity is to hold). So how can you say that CoE is a red herring and straw man argument, when as far as em drive effect apparent impossibility is concerned, apparent CoE breaking fits the bill as much as apparent CoM breaking ?(10mN corrected to 10µN, thanks, wanted to leave margin against uncertainties, don't change the argument, could be ever so slightly above photon rocket, .2µN for 50W for instance, already apparently breaking CoE...)What I wrote is that assuming constant acceleration at constant power is a straw man argument.I also add to that now that assuming a limiting velocity as a constraint is another straw man argument.Perhaps I should add a list of unwarranted assumptions to the EM Drive wiki ?Efficiency of vehicles is governed by thermodynamics, and not just based on kinematics or dynamics or frame-indifference.
Quote from: Rodal on 06/06/2015 04:40 pmLet's discuss this on objective basis, not on what Higgins writes or having a poll on why people have suspicions. It doesn't matter really if most people are more familiar with conservation of energy than conservation of momentum. Nature has its own laws.You yourself said that a CoE issue is a CoM issue and reciprocally (if relativity is to hold). So how can you say that CoE is a red herring and straw man argument, when as far as em drive effect apparent impossibility is concerned, apparent CoE breaking fits the bill as much as apparent CoM breaking ?(10mN corrected to 10µN, thanks, wanted to leave margin against uncertainties, don't change the argument, could be ever so slightly above photon rocket, .2µN for 50W for instance, already apparently breaking CoE...)
Let's discuss this on objective basis, not on what Higgins writes or having a poll on why people have suspicions. It doesn't matter really if most people are more familiar with conservation of energy than conservation of momentum. Nature has its own laws.
Let's discuss this on objective basis, not on what Higgins writes or having a poll on why people have suspicions. It doesn't matter really if most people are more familiar with conservation of energy than conservation of momentum. Somebody already started a poll on people's beliefs on the EM Drive.While I use Bayesian Statistical Analysis (on things like the stock market, that are driven by people's beliefs) to make a living, this emphasis on what people in this forum believe regarding something governed by Nature escapes me.Nature has its own laws.
Quote from: frobnicat on 06/06/2015 05:17 pmI still don't get your inclusion of second law in that.Could you please explain what is your proposed phenomenology of not constant acceleration at constant power ? a(t) = function( power(t) + what else ) ? Have you a precise idea or is it just a hint ? Since you seem to discard completely a(t) = cst * power(t), do you see any consistent alternative ?You can't break the first law. Agreed. You cannot break the 2nd law either (most of the time at least )All you prove by assuming unwarranted assumptions (constant acceleration at constant power) is that, Ahem , your assumption (constant acceleration at constant power) was unwarranted.If you want to prove more, you can go for example, next to the 2nd Law, that should impose further restrictions on efficiency.
I still don't get your inclusion of second law in that.Could you please explain what is your proposed phenomenology of not constant acceleration at constant power ? a(t) = function( power(t) + what else ) ? Have you a precise idea or is it just a hint ? Since you seem to discard completely a(t) = cst * power(t), do you see any consistent alternative ?
...Where exactly your second law fits in this picture ? In my picture of a perpetuum movement of the first kind from constant thrust at constant velocity at constant power, second principle is respected as inefficiencies bleed (and radiate in space) waste heat at every step. Only if averaged thrust/power ratio don't exceed 1/c this schemes becomes impossible, from 1st law alone. Second law only brings a small margin above 1/c before we are in trouble, and with 50µN at constant velocity for 50W, for 40s, we are in trouble.
Rather than try to keep up with this conversation on preferred frames and CoM, CoE violations. Here is the solution. I've updated both of my recent papers and the solution to this Energy Paradox problem is simply Einstein's Equivalence Principle, and once you read it you will understand that it makes no difference if it is conventional propulsion, a photon rocket or an EM Drive, CoE and CoM are NOT violated.Please read it and add them to the Wiki so this paradox can go away and the straw man can go back to scaring crows. (ha ha ha)Regarding the preferred frame. Is the gravitational potential you are standing in now a preferred frame, relative to one at a different altitude? Granted, I prefer sea level with a cocktail myself. Thank you and enjoy!Todd
Can you please explain to me, a lowly chemist, how this solves frame invariance? I dont think that there should ever be a limiting velocity aside from c.
Quote from: Tetrakis on 06/06/2015 07:54 pmCan you please explain to me, a lowly chemist, how this solves frame invariance? I dont think that there should ever be a limiting velocity aside from c.Frame invariance, meaning "Lorentz Invariance" is not applicable in an accelerated reference fame. It is not even applicable when the acceleration value is small. In order for frame invariance to be applied correctly, it must be comparing two inertial reference frames where acceleration = 0. It does not equal 0 in a gravitational field or in a ship with a constant thrust-to-power ratio.
Could the EM Drive create an artificial gravitational potential?
....I am sorry to keep dragging this out. My feeble engineer's brain keeps dropping into thought experiments. Given the conclusions reached in your "Resolution" paper, what would be the result of this scenario?Assume two identical self-powered emdrive "stages" operating in series. Turn on Stage 1. According to your Resolution, it will attain some delta-v (with respect to the initial power-up?) that depends on its thrust-to-power ratio. Now physically detach Stage 2 and turn on the power. What will happen?
Quote from: WarpTech on 06/06/2015 07:29 pm...Could the EM Drive create an artificial gravitational potential?Gotta ask, given your analysis so far what would need to occur inside the EmDrive for it to create an artificial gravitational potential?
...Could the EM Drive create an artificial gravitational potential?
I have a question Todd on your Resolution of the Space-Drive Energy Paradox paper.It pertains to the following section, so I include it here:...In order to remain stationary at a given altitude in a gravitational field, a constantforce must be exerted, along with a constant acceleration and a constant input power.There is no gain in altitude, no increase in the potential energy and no increase invelocity. Although power and force are being expended constantly. Question: When a conventional machine is hovering in a gravitational field, like a helicopter or a falcon 9, it is expending power constantly to generate a force equal to the force of gravity. There is no gain in kinetic energy of the machine. All of the power being expended is transferred to surrounding air in the case of the helicopter or propellant for the falcon 9. When an EMdrive has reached it's limiting speed, and is expending power with no gain in kinetic energy,where does this power go such that CoE is obeyed?
Quote from: Prunesquallor on 06/06/2015 09:11 pm....I am sorry to keep dragging this out. My feeble engineer's brain keeps dropping into thought experiments. Given the conclusions reached in your "Resolution" paper, what would be the result of this scenario?Assume two identical self-powered emdrive "stages" operating in series. Turn on Stage 1. According to your Resolution, it will attain some delta-v (with respect to the initial power-up?) that depends on its thrust-to-power ratio. Now physically detach Stage 2 and turn on the power. What will happen?Assuming identical input power is available, when you detach Stage 2 from Stage 1, it now has half the mass, so it can accelerate up to ~ 2*delta-v.
...Have bought a few to measure up and using the EMDrive Calculator to see what resonate frequencies and excitation modes it can work with, versus predicted Df and thrust.
Quote from: WarpTech on 06/06/2015 09:41 pmQuote from: Prunesquallor on 06/06/2015 09:11 pm....I am sorry to keep dragging this out. My feeble engineer's brain keeps dropping into thought experiments. Given the conclusions reached in your "Resolution" paper, what would be the result of this scenario?Assume two identical self-powered emdrive "stages" operating in series. Turn on Stage 1. According to your Resolution, it will attain some delta-v (with respect to the initial power-up?) that depends on its thrust-to-power ratio. Now physically detach Stage 2 and turn on the power. What will happen?Assuming identical input power is available, when you detach Stage 2 from Stage 1, it now has half the mass, so it can accelerate up to ~ 2*delta-v.Let's change the question up a bit. After Stage 1 has been powered for long enough that it's maximum delta-v has been achieved, turn it off. Don't detach it this time. Your spaceship, made of the two identical emdrive stages, is now floating through space at delta-v plus whatever initially velocity it had. Let's say that the spaceship is in deep space, negligible gravity. In this inertial frame, the spaceship has no way of "knowing" whether it is moving or standing still. How does Stage 2 "know" it is currently moving at it's limiting velocity, without invoking a preferred frame? ...