megadrive inertial drive, how does 2nd harmonic make it chooch?

[coppercone2]

Does anyone understand the apparently goverment funded megadrive project that uses a piezo disk stack to generate motion?


Now I read the paper about it, and what I could understand is that the author seems to agree that if you have a row boat, and instead of ores, you have two buckets that you fill with water, displace and then drain the water out of, its possibly to play games with center of mass to make a inefficent propulsion system (i.e. imagine you run a hose through your arm sleeves from a big tank to keep filling buckets).

Ok, so I think that analogy makes sense, but then the author of the paper says the 'key' to the operation of the device is the 2nd harmonic, so if you have a ultrasonic disk stack you are running at 40KHz, the idea is the 'work' is being done by a 80KHz signal that is summed with the 40KHz signal. This was on some forum described as making the 'larmor radiation' directional.

 I don't understand this. So I got a function gen and made it generate a 40Khz 1Vpp signal, and summed it with a 80Khz 1Vpp signal, to get a rather odd waveform (phase shift dependent). I am imagining that the peak voltage is graphable against displacement of peizo stack (after all, it gets longer or shorter proportional to voltage). I don't see how adding the 2F frequency (second harmonic) does anything at all other then I guess change the average shape on the surface of the cylinder from deformation. The author made it out to be that the timing/phase of this 2F frequency is the 'key' to the whole thing...

So I have an amplifier that can do F + 2F into a piezo if I wanted to, but I am not getting what its doing, it just changes the mechanical transformation rates and amplitudes over time.

What am I not getting?
 The paper I read specifically said that a normal ultrasonic cleaner (powered by sineform) will not create a displacement force, but a ultrasonic cleaner modified to inject 2F into the power system will act as starfleet technology. I am not seeing the comparison between draining/filling buckets to change a systems mass and adding a 2F component to a ultrasonic stack. I don't understand GR too much but I feel like I am not seeing anything that would make the system 'directional'.


https://physics.fullerton.edu/~hal/JMP-MachII.pdf

they say this

The objective is propellantless propulsion, where the rest mass of some object, a
stack of PZT crystals in fact, is caused to fluctuate periodically with a varying applied voltage. A second
periodic force is applied to the stack, acting in one direction when the stack is less massive, and the opposite
direction when it is more massive, to produce a steady thrust in one direction. If the piezoelectric effect
were the only electro-mechanical effect present in the crystals, a mass fluctuation would be produced, but
no thrust would be generated. To generate thrust you have to apply a voltage to the stack comprised of two
frequencies, one to produce the mass fluctuation, and the second to produce the mechanical oscillation at
the frequency of the mass fluctuation to generate a periodic force. The frequency of the second force turns
out to be twice the frequency of the voltage that produces the mass fluctuation.

can anyone explain this in greater detail? maybe a sketch of what its doing here or how it changes when it gets the extra frequency ?

I see it as
1) shaking cleanly
2) shaking  differently.

here is what the tones look like
https://www.electronics-tutorials.ws/wp-content/uploads/2018/05/articles-harmonic2.gif they are using the 2nd waveform from the top on the right side of the picture, with some kind of control (amplitude or phase)

What the hell makes them think a tone is changing the larmor radiation pattern ? its making me think of DC balance in a welder kind of. does anyone see that changing the phase or amplitude of the 2F frequency while its already got mechanical energy in the system 'imbalancing' it to follow some kind of gradient? its very similar to a vibration cancellation system I think.


The description makes it sound like I am missing the GR part of the explaination, I only see the piezo stack density changing, not the mass. I am just seeing the density modulated by F+2F, where mass is constant, but volume is dependent on electricity. Clearly something has to happen with mass. what am I not getting? The bucket analogy still depends on mass transfer, its just peicewise, non congruent, but the water still needs to enter and leave the bucket, even if its not during the motion. the system is not considered ready for the next action until the water leaves the buckets so more water can enter. What is the equivalent to the water flow in the buckets in the electronic/mechanical circuit?

[coppercone2]

this is what a piezo stack does with voltage
'

the center of mass would need to change. How does 2f change COM? No matter what waveshape you fed into it, it does not seem to change center of mass, from my steady state analysis. You are adding inflection points by adding the additional frequencies.. so the pattern of deformation changes.. but I don't see a COM shift. It has to be some other effect thats not explained that no one is considering?

That is, if I put a pin in the shape that is changing size, it would not want to move from the exact middle point for any reason I can think of.

So at 0V, its natural shape. As voltage increases the cylinder gets longer, as voltage decreases it goes back into the original shape, and as it goes negative you get the cylinder fatter.  Phase seems to be just changing the duration of time it spends around a specific size, that is it might hold that size for a little longer or spend less time being in that size. It still seems entirely omnidirectional. Is there something happens when there is mechanical energy resonating in the system from previous operations that the change in the voltage feed causes it to get in some way biased?  I am pretty sure I saw this in pyhsics class where he has a wobbulator attached to a string hanging off a pully on the end of a table with a mass on it, if you increase the mass the string gets tighter, so it constricts more, and it gets longer, but nothing special happens.. right?

[T3sl4co1l]

Here's some relevant math:
https://physics.fullerton.edu/~jimw/stargates.pdf
I haven't worked with GR math so I don't follow it too closely, but he does indicate a lot of assumptions, which might not pan out.  I didn't notice offhand the other explanation, but what I recall (from the accompanying short book on the subject) is it can also be expressed as a Taylor series in terms of acceleration (and higher orders) between reference frames.  The familiar case (to the extent relativity is familiar..) is approximated by truncating those terms, and justifiably so as they're extremely small for any reasonable acceleration (i.e. not in the vicinity of a black hole).

The merit, then, is based on how close to zero those terms actually are, and if we can detect any minuscule error at all, attributable to them.  These are notoriously difficult measurements to make, after all, with microgram forces in play, and endless sources of error, from gas desorption to thermal expansion.

So, by sloshing energy around, and accelerating it at the same time -- or perhaps harmonics thereof, also while checking against phase shift -- we can perhaps tease some of those terms.  Trouble is, materials just aren't very strong compared to the magnitude of acceleration, or energy density, required; we're lucky if we can even reach the threshold of measurement.  But if we can, and the result is statistically sound -- it's a start.

Tim

[coppercone2]

so whats the control parameter, for direction i.e. which direction does a motor start spinning? does this technology have the need for a directional drive gimmick mechanism like a old motor?

if there is a cylinder it would just randomly get pushed along one of the axis each time you started it? or can the theory explain it to the sense of how to make it move left and right .

so if one makes a nacelle pair out of these, does the space ship randomly spin or go backwards on every start up? I imagine in this case they would need gimbals on this starship so it can rotate its thrusters

[coppercone2]

this one is tempting because I have the amplifier I need, the bottom of a failed ultrasonic cleaner and a sapphire edge balance.. but only for one disk

And I do wonder, why is it ultrasonic? I.e. my piezofan runs at 60Hz. Well actually I can't play with that because when I bought it I got the wrong literature and Asked to modify it to 40KHz, because I thought it was 60KHz, so I asked him to mod it to 40KHz and he modded a 60Hz (not KHz) device that should plug into the wall and run on mains to a 40Hz device that would run on mains in the 20's. i tested it with the best amplifier I have and at 40Hz I do get it to wobble up and down slightly but the voltage is low.. anyway the lesson is piezo device can be low frequency..

ultrasonic just complicates it.. I think the disk stack would behave exactly the same if you made it run on low frequencies by whatever design parameters control that. Does something extra happen with ultrasonic for relativity? I thought its all basically slow as fuck unless you get to say 0.2C

[T3sl4co1l]

Well, it needs bulk moving mass, and you aren't going to do that at MHz, you get numerous bulk waves up there, it's just wiggling jelly.  Down at those frequencies, it can be a 1/2 wave stub and much of the mass moves as one.

Presumably, thrust would be parallel to the wave propagation mode.  A cylindrical piezo (electrode inner and outer walls) would balance and do nothing.

Tim

[Nominal Animal]

The core idea in the inertial drive here is to somehow affect the mass of the device in sync with vibrating the center of mass.  If you do a small device that has two vibration motors, one in the plane of the travel, and one perpendicular to it, you can duplicate the idea behind the paper, with the difference that instead of reducing the mass of the device, the perpendicular vibration motor pushes the device off the surface it is traveling on.

In other words, the displacement of the center of mass is in sync with a minute change in mass of the entire system.  This periodic change, or oscillation in mass, is explained via Mach's principle.  I don't buy it.

The problem in the experiment is that microNewton measurement requires a torsional thrust stand, and those can easily be affected by rotation (in the same axis as the thrust stand) and vibration (depending on the properties of the torsional spring used).  Unlike they claim, the phase of the vibration relative to voltage applied (and thus heating effects) can be significant.  (They say that because one of the test rigs had a ninety degree phase difference to others wrt. voltage applied –– it was in phase with voltage applied unlike the others ––, and since it showed no thrust, vibration could not be the cause of the minute observed effects.  Bullshit; of course phase matters.)  So no, I don't trust their measurements (in the 0 to 5 µN range) at all.

This reminds me somewhat of Eugene Podkletnov, who in the nineties claimed to observe a mild (up to 2%) gravitic shielding effect by rotating ceramic superconducting disks.

In the fringes of science and in the tinfoil hat land, tales of rotating plasma and rotating superconductors having (electro)gravitic effects abound.  I cannot, and will not say, that they are bunk, since they just haven't been investigated rigorously yet.  It's too costly (to do correctly), with more important stuff like fusion reactors easier to achieve; and anyone getting into this will have their reputation forever tainted as a crackpot.. but to my personal nose, this article does not ring true.  I could be wrong, of course, but I don't think so.

To EEs, a more classical idea having been floated before is to use electrons or photons, and internally re-capture them.  That does not work, because total linear momentum is conserved, even when a lattice absorbs an electron, or an electron absorbs a photon.  This is the key idea behind solar sails, after all.  The reason the sails are reflective on the sunward side is because reflecting a photon back the way it came yields a double momentum kick (again, because linear momentum is conserved); and the sails are preferably black (absorb photons) on the side towards the direction the sail is traveling, because absorbing a photon gives half the momentum kick than reflecting it away.  If you can radiate the absorbed photon on the sunward side somehow, even better, although that is likely quite difficult to achieve (perhaps for some wavelengths it can be done, with any extra energy used in a laser directed back to the sun).

Like here, many ideas have at their core a tiny small black box that lets them ignore the conservation of say linear momentum: typically, that a conductor capturing an electron or a photon somehow does not cause the conductor to absorb the momentum of the electron or photon also.  In this case, the black box is the oscillation of the mass of the vibrating piezo element.  I suspect that the easiest way to verify/counter that paper would be to vibrate the system in a perpendicular direction at a specific synchronized (fractional) frequency, and check if that shows any effects from the claimed mass fluctuation (frequency or amplitude change).  It will, if the mass does actually fluctuate.  Since the mass fluctuation is voltage induced, comparing the perpendicular vibration in no-voltage-applied to voltage-applied situation should show conclusively, if there could be something there.

[m98]

Without having worked through that paper, my guess is that the effect they have observed comes from angular momentum being converted to linear momentum by a lever. Don't know if anyone has ever given that a formal name, I call it "office chair propulsion". You can move your chair just by quickly shifting your weight, seemingly without pushing off of something. You are, but it's the floor.
Same thing here, the apparatus is mechanically constrained in two axis by the thrust balance. I'd be impressed if that method still produced any thrust in Microgravity.

[coppercone2]

I hope this idea did not come up from the idea that phase shift 90 degrees is not the same as 90 degrees geometry

when you say two motors that makes me think of two directions being required, but adding a phase shifted wave superimposes on the piezo input

[Nominal Animal]

I hope this idea did not come up from the idea that phase shift 90 degrees is not the same as 90 degrees geometry

Hell no.

when you say two motors that makes me think of two directions being required, but adding a phase shifted wave superimposes on the piezo input

No.

The two motor analog is only an analog, attempting to illustrate the basic idea.  Let me explain in detail, and compare it to the described drive.

Both have a mechanism to oscillate their center of mass.  In the drive, this is the primary frequency of the piezo stack.  In the analog, this is the vibration motor that has its axis perpendicular to the surface the analog is sitting on.

The drive paper claims that a second harmonic imposed on the piezo stack causes a mass oscillation effect, explaining this vaguely by invoking Mach's principle.  (You can argue they talk about inertia and not mass, but existing experiments have proven that inertial mass equals heavy mass to within our measurement precision (high), and the fundamental mechanism they claim is basically the oscillation in mass of a closed system, anyway.  You see, the "range" of Mach's effect described is limited to the system containing the drive, and the mass moving at its center in a specific way is the cause of the oscillation in inertial mass of the rest of the system.  This is why small components are needed for this experiment, too: fast speeds, short ranges.)

In other words, that by synchronizing the mass (or inertial) oscillation with the oscillation of the center of the mass, they can produce thrust.

In my analog, the second vibration motor has its axis parallel to the surface, and causes the mechanism to bounce off the surface.  When the two motors are in sync, with a correct phase difference, the bounces caused by the second motor occur with the first motor in the same phase, thus bouncing off the surface with the same inertial vector, generating thrust.  Of course, here the thrust is generated by bouncing off the surface, while the drive claims an exotic inertial mass oscillation effect in a piezo stack, but as an analog, it's the closest one I could come up with.

My analog is the actually working one.  I do not think their piezo stack actually generates thrust, and what they measured was due to interaction of the piezo stack with their measurement setup.

In my analog, you can replace one of the vibration motors with angled "hairs" (springs) at the bottom surface, and it'll move even better.  But it is no longer analogous to the drive here.  (The second motor, by jumping the analog off the surface, is the sort-of-analog of the inertial mass oscillation effect in the drive paper.)

The paper states that without the second harmonic frequency, they don't see any thrust.  They also say that when the phase shift between the primary frequency and the second harmonic is zero, they see no effect; and somehow, because of that, it cannot be an interaction with the experiment setup.  That "somehow" is the bullshit part: of course the phase shift between the primary frequency and the second harmonic can make the difference, because it affects the overall waveform of the piezo stack and therefore the center of mass; and when coupled to a measurement system with a (torsion) spring, the exact shape of the waveform (especially phases of the harmonics) can obviously affect the strength of the coupling, depending on the properties of the (torsion) spring –– this is damn easy to experimentally verify, too.  Even metal fatique could be involved.  Basic stuff.

The correct experiment setup would have had a separate oscillator, preferably mechanic (and not piezoelectric) – a spring type would be optimal, in a perpendicular direction, with a careful measurement of position along this axis.  When oscillating along this axis, one would compare the oscillation to when the piezo stack is unpowered, and when the piezo stack is powered with various waveforms, including the primary plus second harmonic with a 90 degree phase difference.  There is no need to try to measure thrust in this case, because the point is to verify whether there is indeed a mass/inertial oscillation.  If there is, the position (frequency/phase) along the separate axis will differ if there is inertial mass oscillation: if inertial mass oscillation frequency is higher, it will be imposed in the perpendicular position; if lower, it will show up as modulation in the perpendicular position.

I admit, I'm pretty familiar with the claims by Podkletnov, Ning, et. al., because I'm the personality type who does not feel threatened by standing on the precipice of their understanding, and gazing into the abyss filled with foil hatted nutjobs, because sometimes there is a truth somewhere under there.  In this case, I think this is more about the authors choosing an unconventional explanation for an effect, one they could have trivially ruled out, just so they could write an intriguing paper on it.
This happens way more than you'd think; even in physics, more than one paper in ten is like this.  (I don't know much about other subjects, as I mostly read physics and computing articles myself.)

[maarten42]

A bit late perhaps, but alas. Let me try to clear this up.

The formula Woodward derived from the Einstein field equations shows the that inertia of an object not only depends on its rest-mass, but also on the 2nd derivative of the energy density. The math is reviewed again and again and seems to be correct. Whether this is a real effect still remains to be seen.

This mass fluctuation is transient being dependent on the 2nd derivative. Also, the math is such that the energy changes must come from deformation due to acceleration (sh presumably so shaking a capacitor and just powering it synchronized won't work).

So:
1- shaking something without deformation does not work.
2- symmetric shaking with deformation cancels the nett effect.

Adding the 2nd harmonic in piezo drive ensures that the acceleration (and hence the mass fluctuations back en forth) do not cancel each other out:

sin(x)+1/4 cos(2x)

edit: typo in formula

[coppercone2]

this might be relevant,
https://www.nature.com/articles/s42254-019-0037-3

and it turns out
http://physicsbuzz.physicscentral.com/2019/03/sound-waves-may-have-negative-mass-new.html

that is a key ingredient in alot of theories

Anyway, those two articles make you think that maybe its gonna work I think, or that at least something funny is going on.

I have a little trouble understanding what you wrote because it seems to require some advanced math solutions to get through. Maybe I can figure those out, since this is interesting enough for me to care about the math.

Kinda makes me wish I made some other choices with test equipment purchases


The inertia concept is difficult to grasp, but I think I understand something now. I was just imagining the piezo observation by observation (i.e. that the voltage at each step corresponds to a material dimension, where Voltage equals some amount of compression or elongation, so Vin=width).  Maybe it would help if I figured out a small transient simulation between Time = x and time = y within the time constant of the material, so I can imagine the wobble. So I just imagined a box that is slightly expanding or contracting. I guess thats real basic. Should I be thinking about this piezo in terms of mechanical reflections like a waveguide?

I guess I don't understand piezos well. Are they electrically conductive or is it just a material interacting with a E-field? If its just reacting to the electric field (i.e. bias) and not electron conduction, it makes its response feel 'more instantaneous'.

If I had a parallel plate capacitor and shoved a piezo material in there isolated from the plates on a clamp floating between the capacitor (like a e-field test setup), would it expand and contract, or does it need electron flow, sintered electrical contacts, etc? I guess I really skipped on this topic.. at least I have something to do now. I ignored them alot because piezos resonators sound super annoying.

In a transient analysis, once you apply the field, where does the 'onset' of inertia take place (first point of materials expansion)?

[AVGresponding]

[coppercone2]

does that 10 minute long video without a table of contents answer if a piezo material will react to just a electric field without direct contact?

[maarten42]

I guess I don't understand piezos well. Are they electrically conductive or is it just a material interacting with a E-field? If its just reacting to the electric field (i.e. bias) and not electron conduction, it makes its response feel 'more instantaneous'.

I am not an expert but as far as i know that is more or less correct. Consider however the size and speed of sound in the quarz: that limits the maximum frequency.

In a transient analysis, once you apply the field, where does the 'onset' of inertia take place (first point of materials expansion)?

Not sure what you mean by this. If you mean how the transient mass-fluctuations are supposed to be initiated: the second derivative of the stress-energy in the piezo-stack (or other spring material, piezo just makes it easy to drive the resonance).
e.g. when the stack length varies with sin(t)+1/4cos(2t), the stress-energy scales with (sin(t)+1/4cos(2t))^2. Now calculate the derivative and fill in the formula.
 wwmach-formula.png (7.08 kB. 406x87 - viewed 53 times.)

I would advice to read "Making starships and stargates" from Dr. Woodward.

[AVGresponding]

does that 10 minute long video without a table of contents answer if a piezo material will react to just a electric field without direct contact?

If you watch it you'll find out.

I guess if you're too lazy then the TLDR: is "yes".

[coppercone2]

If its just proportional to E-field, a fun experiment or demo might be to make a plastic go/no-go gauge and then show that a ceramic plate fits or does not fit into the gauge when a big parallel plate capacitor is energized. I wonder if a table top demo is feasible (for use in 1950 though, its too dangerous for todays world). I am not sure I ever saw even a drawing of one working without direct contact with the plates.. sounds like it might be unnecessary.

It ties into my other unfinished project about making a e-field generator of some kind (like compliance tester).

But anyway, I am still researching.

Not too lazy I just have so many things on my mind trying to make this concept fall into place... almost worried a video might distract me from some creative (even if incorrect) thinking. I suspect this theory is prone to 'dogma' related problems.

[Nominal Animal]

The problem in the practical application of the Woodward formula is that you cannot treat the piezo elements 1) as point-like objects, nor 2) in isolation.

For the drive to work, the mass of the entire system must fluctuate; it is not enough for the mass distribution to fluctuate (as happens with e.g. sound waves).  If it were otherwise, we could use large solenoids to achieve the same effect.

In any case, my main objection is to the experimental setup, and the inferences drawn from the results.  The error sources are hand-waved away, while on the same order of magnitude as the observed results.  I typically see similar 'optimism' in papers written to solicit additional funds, not from true scientific discoveries.

That said, I do not know how to set up an experiment to verify the Woodward effect, myself.
Setting up a battery-powered piezo stack inside a spherical shell, for the mass of the sphere to be observed using a typical precise torsional measurement, is not that hard; but keeping the vibrating sphere in place for the torsional measurement to be accurate, is physically impossible: hold it tight, and it won't vibrate. Let it vibrate, and the vibrations will mess up the measurement, like I described earlier.  Hold it separately, and the torsion arm is no longer rigid, and the measurement is unreliable.

Even using a secondary stationary shell (with the 'engine' vibrating inside) won't really work, because the torsional measurement must be so close that the varying mass distribution inside the secondary shell will affect the measurement.  (That is, if you put a lead weight off center inside a wooden sphere, and measure its mass using a torsional measurement, the measurement will depend on the orientation of the sphere.)

Testing an actual engine in microgravity in vacuum would be the obvious choice, but the price tag is still too high.  And even then, you need a series of experiments, to eliminate the effects of light pressure, thermal differences, outer atmosphere drag, and so on.

[coppercone2]

I wrote something but then I realized maybe I totally misread.

I have made high voltage piles before out of coin cells. You can get a nice and high voltage from them.. within piezo levels. I doubt direct drive with coin cells would be enough.. (get yourself plastic tweezers if you want to mess with this, an absolute must)

The smallest ones would be DC/DC converter modules meant for use with I guess geiger counters (500V).. but their pretty weak. Just trying to imagine this test sphere makes me think its gonna be totally massive.


What do you think the power level of the piezos would need to be to study this? Like how many G's and how watts. I wonder what his piezo pile voltage is too. I am guessing that is a sub kV module based on the wiring in the picture, there appear to be no special precautions taken to deal with high voltages. ~100V standard parts?