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#2420 by PotomacNeuron on 24 Oct, 2017 15:32
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Pictures of the flexure bearings that arrived last week. Since the noise problem seems to have been solved for now, I will keep these for a potential future test stand and not worry about using them now.
The larger one is the E-10 bearing, which is the same used by Woodward/Fearn in the USC/ARC style thrust balance. The other two are the D-10.
Where did you buy the bearings? $? I am interested in doing some Dean Drive experiments. I searched in google shopping but did not find a seller. Thanks. -
#2421 by Monomorphic on 24 Oct, 2017 15:59
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Pictures of the flexure bearings that arrived last week. Since the noise problem seems to have been solved for now, I will keep these for a potential future test stand and not worry about using them now.
The larger one is the E-10 bearing, which is the same used by Woodward/Fearn in the USC/ARC style thrust balance. The other two are the D-10.
Where did you buy the bearings? $? I am interested in doing some Dean Drive experiments. I searched in google shopping but did not find a seller. Thanks.
https://c-flex.com/ PM me if you want the contact information for the lady who processed my order. They are ~$50 each.
Also attached is their brochure with bearings listed. Was interesting to find out that the 19cm length of #14 piano wire I am using has slightly less torsional spring rate (0.00326 lb-in/degree) than one of the E-10 bearings (0.0037 lb-in/degree).
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#2422 by WarpTech on 24 Oct, 2017 16:09
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The problem with the example above is that there is one single type of energy that is precluded from entering the stress-energy-momentum tensor: gravitational potential energy.But, besides the theoretical reasons, there is not a single reproducible experiment where someone has been able to extract energy from the Quantum Vacuum.
Consider the following thought experiment:
In the reference frame of a distant observer, outside of a gravity well, looking "down" into it. He sees an atom falling from height h1 to height h2 < h1. In doing so, the atom's oscillation transitions to and from the ground state becomes red-shifted, due to gravitational red shift.
Since the frequency of the atomic oscillations decreased, in the frame of the distant observer, the energy of the oscillator was also decreased;
h*f1 > h*f2
E1 > E2
In falling from h1 to h2, the atom lost energy. In this distant observer's frame, the atom's ground state energy is lower at h2 than it was at h1.
Given this example, and the fact that the ZPF sets the ground state energy of the atom. All Hydro-electric power is essentially extracting energy from the Quantum Vacuum.
Thus, from the point of view of General Relativity, if only the gravitational potential energy changed, then the stress-energy-momentum tensor T did not change in the example.
See: https://physics.stackexchange.com/questions/45145/potential-energy-in-general-relativityQuoteGravitational energy cannot be explicitly included in the Einstein field equations because the equivalence principle --there is always a local inertial frame(the free-falling one) in which spacetime looks like the ordinary, flat, special-relativistic one. Hence if there was a frame-independent local notion of gravitational energy, i.e., a tensor, that tensor is zero in some local frame, and hence zero in every frame.
Repeat: that tensor is zero in every frame !
and I think that very few people will agree that "All Hydro-electric power is essentially extracting energy from the Quantum Vacuum."
instead it is essentially extracting energy from the Sun, because it is the Sun ultimately responsible for the weather process responsible for replenishing the high water reservoir thus enabling a continuous process of hydroelectric power generation.
And yet... in the frame of a distant observer, the energy of the water atoms themselves is lower at the bottom of the well, and the energy density of the water is greater. In terms of the PV model, if at the distant observer the refractive index, K=1 and in the gravity well K > 1, then;
E(K) = E/sqrt(K) < E
U(K) = K*U > U
So the T00 term of the "water" must change. The sun can heat water all it wants and increase its kinetic energy, but unless there is a gravity well, there is no Hydro-Electric power. (Steam engine, sure) The sun puts back, what the gravity well steels from the atoms in the water.
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#2423 by PotomacNeuron on 24 Oct, 2017 16:11
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Pictures of the flexure bearings that arrived last week. Since the noise problem seems to have been solved for now, I will keep these for a potential future test stand and not worry about using them now.
The larger one is the E-10 bearing, which is the same used by Woodward/Fearn in the USC/ARC style thrust balance. The other two are the D-10.
Where did you buy the bearings? $? I am interested in doing some Dean Drive experiments. I searched in google shopping but did not find a seller. Thanks.
https://c-flex.com/ PM me if you want the contact information for the lady who processed my order. They are ~$50 each.
Also attached is their brochure with bearings listed. Was interesting to find out that the 19cm length of #14 piano wire I am using has slightly less torsional spring rate (0.00326 lb-in/degree) than one of the E-10 bearings (0.0037 lb-in/degree).
Thank you! By actually starting to do some research for the experiment I wanted to do, I suddenly lost interest. Sorry for wasting your time ! I will write up why in a separate post.
As to the comparison of piano wire and the E-10, Can't the piano wire be left long enough to achieve small torsional spring rate (torque/degree as in LB-IN)? So that 0.00326 might be of certain length? My balance wire was about 4 feet long so it is very sensitive. -
#2424 by Monomorphic on 24 Oct, 2017 16:18
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As to the comparison of piano wire and the E-10, Can't the piano wire be left long enough to achieve small torsional spring rate (torque/degree as in LB-IN)? So that 0.00326 might be of certain length? My balance wire was about 4 feet long so it is very sensitive.
Yes. 0.00326 lb-in/degree is for a certain length and diameter of wire. The longer the wire, the less the torsional spring rate. The thinner the wire the less torsional spring rate. 4ft of #14 piano wire would have a torsional spring rate of 0.000508 lb-in/degree. -
#2425 by Rodal on 24 Oct, 2017 16:24
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...
It may change in your PV model, but not in Einstein's General Relativity (if the only difference is potential gravitational energy).
So the T00 term of the "water" must change. The sun can heat water all it wants and increase its kinetic energy, but unless there is a gravity well, there is no Hydro-Electric power. (Steam engine, sure) The sun puts back, what the gravity well steels from the atoms in the water.
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#2426 by WarpTech on 24 Oct, 2017 16:29
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IMO GR is a misinterpretation of a quantum mechanical process, as being space-time curvature. Space is what we measure with rulers, time is what we measure with clocks. If there is curvature, it is the instruments that are deformed by fields, not the empty vacuum that is geometrically curved....
It may change in your PV model, but not in Einstein's General Relativity.
So the T00 term of the "water" must change. The sun can heat water all it wants and increase its kinetic energy, but unless there is a gravity well, there is no Hydro-Electric power. (Steam engine, sure) The sun puts back, what the gravity well steels from the atoms in the water.
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#2427 by Mulletron on 24 Oct, 2017 16:39
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Is there some possibility of a Maxwell's Demon here?
If the Quantum Vacuum is the zero energy point, that means that you should not be able to extract momentum or energy from it, because the momentum/energy gained by the EM Drive would be subtracted from the QV, which contradicts its zero point nature, so what you thought was "zero point energy" really wasn't.
ie. some kind of Quantum Feedback Loop whereby you're able to push off the Vacuum fluctuations in a directionally biased way
https://en.wikipedia.org/wiki/Quantum_feedback
(so the Dynamic Vacuum would be the external field)
I was thinking it's probably better to think about doing the exact opposite of extracting energy or momentum from the QV. I'd like to see and understand more about these developments before I can seriously talk about such things.
https://www.sciencealert.com/physicists-discover-an-unexpected-force-acting-on-nanoparticles-in-a-vacuum
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.133605
https://www.newscientist.com/article/mg20927994-100-vacuum-has-friction-after-all/
https://journals.aps.org/pra/abstract/10.1103/PhysRevA.82.063827 -
#2428 by PotomacNeuron on 24 Oct, 2017 17:03
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I wrote up why I lost interest in Dean Drive experiments in the Woodward thread. There are links for some good reads.
http://forum.nasaspaceflight.com/index.php?topic=31037.msg1741500#msg1741500
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#2429 by Bob012345 on 24 Oct, 2017 18:46
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(...)
It's just a fact of nature that kinetic energy generated in a moving reference frame will appear as greater in some other reference frames (and lesser in others). If any form of propellentless propulsion is possible at all, then you can amplify kinetic energy by judiciously creating it from within moving or rotating reference frames and harvesting it in another. It's no more 'free energy' that needs to be explained any more than a higher relative velocity due to relative motion has to be explained as 'free velocity'. The only thing that needs to be explained is the 'problem' of how and why nature would allow any form of PP to exist which of course many folks are busy working on. To me it just like a planetary flyby maneuver whereby the universe acts as a virtual planet.
Is your actual beef with the EMDrive in general or with the EMDrive as described by TT?
Bob012345,
I don't think shifting your reference frame is going to help you extract KE from anything. If that were possible then you could make a Gyro accelerate itself, which really has been tried many times.
The problem with that argument is this. All the energy of the gyro was input from a non-rotating the reference frame. Accelerating a moving object takes more and more energy, it requires a quadratic input of energy to maintain a constant torque. If you then extract the kinetic energy of course you merely get back what you put in minus losses. But if you can spin up the gyro with a force applied completely within a rotating reference frame, say from a working EMDrive device or other effect, then if the power to create the torque is constant, the total energy to spin it up increases linearly in that frame while the kinetic energy of the gyro grows quadratically in the lab frame. At some point depending on design specifics, the total kinetic energy in the lab frame is larger than the total input energy and that excess can in principle be harvested. I
Keeping the discussion EMDrive related (and not that other drive), Shawyer's proposed interstellar probe design, (if it worked as stated) accelerates at about 1m/s/s with a mass of 8936 kg and an electrical power of 29.6kW. Such a probe would have more kinetic energy in the starting frame than energy input in the moving frame in only about six seconds. After the nearly ten year trip it would have about twenty million times more kinetic energy than electrical input as it flew by at .67c. While I'm not saying I buy these numbers at all, I'm saying that's the benefit of manipulating energy in reference frames if you can really do it.
All I'm really saying is that I believe the benefit of these devices is that they allow manipulation of kinetic energy between different reference frames, which is a fundamental aspect of classical physics, for attaining either great velocity or useful energy or both. -
#2430 by OnlyMe on 24 Oct, 2017 18:53
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No, it does not have to do with "consumption of air," [definition: consumption: the using up of a resource] on the contrary, it has to do with compression of air and ensuing higher velocity ejection of air, as the jets of gas shoots backward, the engine and the aircraft are thrust forward in order to conserve momentum (in the jet engine example)
You jet engine example would only apply if the operation of an EmDrive consumes in some manner the atmosphere within and around it...
Putting such a jet engine inside a shell in a spacecraft will result in zero thrust for the spacecraft.
Concerning the EM Drive experiments in air, you will have asymmetric convection of air (as an inefficient asymmetric heater in experiments performed under ambient conditions) [as a possible source of anomalous thrust in EM Drive experiments under ambient conditons] and thus preserving conservation of momentum. Addressing conservation of momentum is not "arrogance."
Same dog, different spots.
Your assumption seems to be that since everything we have been able to build and test in the past, has required that an engineered change in velocity requires, pushing against a mass or field external to to the drive/engine etc., all of physics is limited to those conditions... That we already know everything on the subject and there is no room for anything beyond what we think we know right now.
It is justified to say this is what we know from experience and another thing to say that how we interpret what we have experienced in the past, places a limit on physical reality. Just because we have not seen it does not mean it cannot happen.
The whole issue reminds me of a quote from, “Thinking fast and slow“, by Daniel Kahneman
"... Which describes a puzzling limitation of our mind: our excessive confidence in what we believe we know, and our apparent inability to acknowledge the full extent of our ignorance and the uncertainty of the world we live in."
The whole discussion is confused by intermingling conclusions based on classical experience and experimentation and theoretical projections not yet proven or even fully understood and then assuming that what we believe within the context of either alone or together, represents practical limitations on physics. The fact is we don’t know everything there is to know about physics, so we cannot say with certainty something (currently unknown) happening inside a frustum might generate thrust, without pushing off of or pulling on something outside the frustum.
When you say with certainty that, no acceleration can occur without interacting with something outside the frustum, you are saying you know everything there is to know. If your argument had been phrased as, this is what I believe, rather than as a certainty that implies we already know all there is to know, it would have been better, the way I read your comments. -
#2431 by Rodal on 24 Oct, 2017 19:35
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...
The whole issue reminds me of a quote from, “Thinking fast and slow“, by Daniel Kahneman
...
When you say with certainty that, no acceleration can occur without interacting with something outside the frustum, you are saying you know everything there is to know. If your argument had been phrased as, this is what I believe, rather than as a certainty that implies we already know all there is to know, it would have been better, the way I read your comments.
Daniel Kanehman has a Nobel Memorial Prize in Economics, "the dismal science" so called for many reasons (including the fact that one cannot have well-controlled experiments in Economics), including that this prize has the dubious distinction that it has been conferred on the same year to people having diametrically different economic opinions.
What I am saying is not (like you incorrectly claim) that I know everything (I never said that), but that I am confident enough to place a financial bet with you that it will turn out as I wrote concerning conservation of momentum, internal and external fields. Unfortunately there is no option market to place such a bet at the moment, as I think that it would be a good financially rewarding bet to place
(of course it would be a matter of what would be the odds in such a market...)
I am also confident that the Sun will rise again tomorrow. I have no 100% absolute certainty about it, and I don't claim that I know everything that could happen to prevent the Sun from rising again tomorrow, but I am confident enough to place such a strong financial bet on that too, and to say so (it is not arrogance, but instead confidence on the laws of Nature). -
#2432 by otlski on 25 Oct, 2017 00:39
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Pictures of the flexure bearings that arrived last week. Since the noise problem seems to have been solved for now, I will keep these for a potential future test stand and not worry about using them now.
The larger one is the E-10 bearing, which is the same used by Woodward/Fearn in the USC/ARC style thrust balance. The other two are the D-10.
If and when you get around to implementing the flexures, be very careful to align the top mount with the bottom mount so the the bores are coaxial to say 0.005 inch. We use precision ground Thomson rod to align. It looks like you have the thin webs which in tension are fair but in compression are weak. Tension mode is when you "close" the smile looking at the end. Any misalignment upon assembly will wrinkle them and linearity and hysteresis will go out the window. Though you will be purposefully loading them axially I assume, you can crunch them while unscrewing a cable out at the end of the arm if you are not careful. If you can, design the mounts not only for alignment but for visual inspection so you can lay eyes on them when data gets weird. -
#2433 by TheTraveller on 25 Oct, 2017 00:46
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I am also confident that the Sun will rise again tomorrow. I have no 100% absolute certainty about it, and I don't claim that I know everything that could happen to prevent the Sun from rising again tomorrow, but I am confident enough to place such a strong financial bet on that too, and to say so (it is not arrogance, but instead confidence on the laws of Nature).
Hi Jose,
See attached.
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#2434 by TheTraveller on 25 Oct, 2017 00:55
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All I'm really saying is that I believe the benefit of these devices is that they allow manipulation of kinetic energy between different reference frames, which is a fundamental aspect of classical physics, for attaining either great velocity or useful energy or both.
Hi Bob,
Choose any frame you wish.
Knowing the force and mass, measure the time of acceleration. Work done is then invarient using Work = (N^2 t^2) / 2 m.
Or measure dV, then knowing mass, KE change is invarient using dKE = (m dV^2) / 2 -
#2435 by TheTraveller on 25 Oct, 2017 01:01
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When you say with certainty that, no acceleration can occur without interacting with something outside the frustum, you are saying you know everything there is to know. If your argument had been phrased as, this is what I believe, rather than as a certainty that implies we already know all there is to know, it would have been better, the way I read your comments.
Hi OnlyMe,
The requirenent is to generate an internal force imbalance that operationally shifts the centre of mass during acceleration.
Remember an EmDrive that is not accelerating, doesn't generate any thrust.
The "Shawyer Effect" is about what happens inside a resonant asymmetric cavity DURING acceleration. -
#2436 by meberbs on 25 Oct, 2017 01:17
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First, you seem to have forgotten that that equation you keep throwing around is derived assuming the object starts from rest. It simply does not apply in anything other than the initial rest frame.All I'm really saying is that I believe the benefit of these devices is that they allow manipulation of kinetic energy between different reference frames, which is a fundamental aspect of classical physics, for attaining either great velocity or useful energy or both.
Hi Bob,
Choose any frame you wish.
Knowing the force and mass, measure the time of acceleration. Work done is then invarient using Work = (N^2 t^2) / 2 m.
Or measure dV, then knowing mass, KE change is invarient.
Second, you seem to have missed my recent post explaining to you that if the emDrive acts as you describe it clearly violates conservation of energy. -
#2437 by TheTraveller on 25 Oct, 2017 01:30
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First, you seem to have forgotten that that equation you keep throwing around is derived assuming the object starts from rest. It simply does not apply in anything other than the initial rest frame.All I'm really saying is that I believe the benefit of these devices is that they allow manipulation of kinetic energy between different reference frames, which is a fundamental aspect of classical physics, for attaining either great velocity or useful energy or both.
Hi Bob,
Choose any frame you wish.
Knowing the force and mass, measure the time of acceleration. Work done is then invarient using Work = (N^2 t^2) / 2 m.
Or measure dV, then knowing mass, KE change is invarient.
Second, you seem to have missed my recent post explaining to you that if the emDrive acts as you describe it clearly violates conservation of energy.
Hi Meberbs,
Acceleration, as far as the accelerated mass is concerned, always starts from a rest frame. Mass knows no starting velocity.
What I described is valid from any frame and results in invarient calculations of work done and changed KE. Try it.
As I have described to you, during EmDrive acceleration, thrust drops as work is done to accelerate mass. EmDrive acceleration is not OU any more than an electrical motor spinning up a mass is OU.
Roger has explained this many times, such as in this attachment.
The KE export increases cavity energy loss per cycle and drops Q, just as it does in every accelerator cavity.
Using Work = (N^2 t^2) / 2 m, it is clear work done to accelerate mass increases as the square of the acceleration time. Thus cavity energy loss to constantly increasing KE, increases as the square of the acceleration time. Then as EmDrive thrust generation is driven by cavity Q, thrust generation decreases as acceleration time increases.
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#2438 by WarpTech on 25 Oct, 2017 01:46
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It may change in your PV model, but not in Einstein's General Relativity (if the only difference is potential gravitational energy).
So the T00 term of the "water" must change. The sun can heat water all it wants and increase its kinetic energy, but unless there is a gravity well, there is no Hydro-Electric power. (Steam engine, sure) The sun puts back, what the gravity well steels from the atoms in the water.
Well, the result would be the same if I used a Schwarzschild solution of GR, rather than the PV Model. The Schwarzschild solution is a vacuum solution, so the stress-energy tensor is zero "0" to begin with because the solution intentionally "excludes" all the matter causing the gravity well. However, in that solution, the effect of a test particle is assumed to be negligible. It has NO contribution to the tensor, so although its density increases as it falls down, it is not included in the result. Hence, why people believe the energy density doesn't change.
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#2439 by Rodal on 25 Oct, 2017 02:02
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It may change in your PV model, but not in Einstein's General Relativity (if the only difference is potential gravitational energy).
So the T00 term of the "water" must change. The sun can heat water all it wants and increase its kinetic energy, but unless there is a gravity well, there is no Hydro-Electric power. (Steam engine, sure) The sun puts back, what the gravity well steels from the atoms in the water.
Well, the result would be the same if I used a Schwarzschild solution of GR, rather than the PV Model. The Schwarzschild solution is a vacuum solution, so the stress-energy tensor is zero "0" to begin with because the solution intentionally "excludes" all the matter causing the gravity well. However, in that solution, the effect of a test particle is assumed to be negligible. It has NO contribution to the tensor, so although its density increases as it falls down, it is not included in the result. Hence, why people believe the energy density doesn't change.
You are actually bringing up a very interesting feature of Einstein's theory. Unfortunately GR admits many solutions some of which are non-Machian (all vacuum solutions as the one you pose that are not Minkowski flat, are non-Machian) but most of the experimental evidence (WMAP) argues instead for Friedman-Robertson-Walker metric over large scales
https://en.wikipedia.org/wiki/Friedmann%E2%80%93Lema%C3%AEtre%E2%80%93Robertson%E2%80%93Walker_metric#Evidence
and over small scales, the evidence is that spacetime curvature (gravity) is due to matter sources.QuoteIt was one of Einstein’s early goals, although he never succeeded, to incorporate
Mach’s principle in his general theory of relativity. It has been generally
regarded that general relativity does not embody Mach’s principle, that is that
geometry can exist independent of matter. It was the Schwarzschild solution
that seemed to bring this idea its early but reluctant acceptance. That is, a
geometry can arise in the absence of a source term, from the vacuum. Of
course, in the practical applications of the Schwarzschild solution to the precession
problem of Mercury and the bending of light, it was always assumed that
looming behind the formal sourceless equation was a real sun. Nevertheless, a
possible formal interpretation has been that a curved space exists without an
identifiable source, thus obviating the need for Mach’s principle
Our result has been to replace the Schwarzschild solution to the sourceless
spherically symmetric static environment, which then, as now seems to allow
the existence of non-trivial spacetime curvature in absence of any matter, with
a solution that does not correspond to a sourceless environment but yet leads
nevertheless to a metric that can approach the Schwarzschild with arbitrary
accuracy in an asymptotic way. In doing so, for this particular case at least,
Mach’s principle, the idea that geometry emerges as an interaction between an
identifiable matter term and geometry is preserved
https://arxiv.org/pdf/1106.2040.pdf
The problem the way I see it is that for the Schwarschild metric, the components have a singularity r^(-n). There are no spacetimes that can remove those singularities (the paper above was an effort to deal with the Schwarschild singularity). See p.78 of Choquet-Bruhat "GR and the Einstein Equations" http://bit.ly/2yQenju
(of course it would be a matter of what would be the odds in such a market...)