Get Tinselkoala to build it in real life?

Alsetalokin, what do you say?

Posted By: Andrew PalfreymanYou've made an error. Please stay late after class.

Fantastic! Oh that IS good news! Thank you so much, i was starting to get into quite the fizz there! Phew!

Panic over everyone, Andrew's sussed it! Knew i'd come to the right place.

So, what have i muffed up this time?

Here's how I think about it.

You can reach the state where the weights all lie along a radius as the central wheel rotates, in two stages. Start with the weights lined up on a horizontal line.

First you let the axles on the circumference of the central wheel be free and you spin up the central wheel. The weights on the two outer wheels continue to lie on horizontal diameters of their wheels because no torque is applied around the outer axles. The angular momentum is (4 m) omega R.

Now to get the weights lined up on a single rotating diameter you have to spin up the outer wheels to the same rate. This gives you the same situation as the tidal locking of the moon. The rotation period of the outer wheels equals their orbital period. It adds another (4m) omega R to the budget. If you wind in the weights as you propose you have to do enough work to kill this momentum. Energy and momentum are conserved.

ETA I suppose the confusing issue that might lead you astray is that when the system is "tidally locked" the axles of the outer wheels do not turn in their bearings. That might lead you to think the wheels they carry are not rotating. But they are.

Posted By: VibratorSo, what have i muffed up this time?

Reality.

Yeah, I liked watching the animation, while thinking "this is wrong".

It's the same problem with this as with other free energy/cold fusion/zero-point energy stuff. Build one and let us know how it goes. But then, that's really the only useful response to stubborn believers. One can argue the point until one is blue in the face--and yet the believer will continue to believe without testable evidence.

I believe this works. The animated gifs are too convincing.
I hope Elon Musk + Jeff Bezos or other stupid Billionaires sink some cash into this.

Posted By: AngusOh goodie!!! Meat and potatoes for the 'trap at last!!

ETA It is wrong to say that the device switches instantly between its two different conditions of angular momentum without work being done.

Quite so.

It is the angular inertia that is instantly changing.

The momentum remains constant throughout - that's what causes the energy gain.

And it's the maths that are saying it - you're looking at a physics sim. Not merely an animation..

Angular momentum is angular inertia times angular velocity. It is conserved, in any closed system of interacting masses rotating about a common axis. Thus if the angular inertia changes, then velocity also changes in direct inverse proportion, conserving their product.

Here, MoI halves, instantly (you can see it happening on the "MoI & momentum" plot). Accordingly, velocity spontaneously doubles, and so the 16 kg-m²-rad/s of angular momentum is conserved - the momentum trace never wavers.

Rotational KE is half the angular inertia, times the angular velocity squared.

Thus, half the inertia at twice the velocity is twice the rotKE. Energy has been spontaneously doubled, by the action of conservation of angular momentum. Complicated huh?

Check Google if you don't believe it - MoI is given by mass times radius squared (mr²), AM is MoI times angular velocity (Iw) and rotKE is ½Iw². These are the ordinary, bog-standard terms - the most basic basics..

Posted By: AngusHere's how I think about it.

You can reach the state where the weights all lie along a radius as the central wheel rotates, in two stages. Start with the weights lined up on a horizontal line.

First you let the axles on the circumference of the central wheel be free and you spin up the central wheel. The weights on the two outer wheels continue to lie on horizontal diameters of their wheels because no torque is applied around the outer axles. The angular momentum is (4 m) omega R.

Now to get the weights lined up on a single rotating diameter you have to spin up the outer wheels to the same rate. This gives you the same situation as the tidal locking of the moon. The rotation period of the outer wheels equals their orbital period. It adds another (4m) omega R to the budget. If you wind in the weights as you propose you have to do enough work to kill this momentum. Energy and momentum are conserved.

LOL right, not sure what you're on about here, or that you've quite caught the brief; you're seeing a basic mechanical interaction in which the net energy spontaneously doubles, without any magic occurring - just the basic, standard rotational KE term (half MoI times RPM²).

You're looking at a real-time energy measurement mate. The output energy is being calculated independently in duplicate, both by me, using the standard metrics you see displayed, and also by the sim's own low-level calculus, untouched by and impervious to my fat fingers. There's zero deviation between the two results. I've already measured it down to 1/10th of a microjoule.

This is precisely WHY i've brought it here - to see if anyone can find an error! Because i can't, and neither can anyone else i've asked.

No obligations of course - please don't feel compelled to chime in if you're not really interested in basic classical physics (terrible bore i'm sure). It's just momentum and KE. If those terms are somewhat mysterious or indefinite to you in any way, there's no shame in sitting it out / spectating..

ETA I suppose the confusing issue that might lead you astray is that when the system is "tidally locked" the axles of the outer wheels do not turn in their bearings. That might lead you to think the wheels they carry are not rotating. But they are.

Mate - it's the maths that are 'astray' if something's wrong. Please, i'm not claiming anything the momentum and KE figures aren't..? It's all there with its guts out, no secrets or obscure formulas..

When the motors activate, the orbiting rotors are not rotating about their own axes - think about it, CF force is either present, or not - axial rotation is thus absolute, not merely relative. The orbital rotation continues, of course - that's the entire point. The axial momentum of the orbiting rotors is conserved when they stop rotating, and transferred over to the orbital axis, causing the KE gain.

So, the entire rig begins with 1 rad/s of orbital rotation. Then the motors switch on, counter-rotating the orbiting rotors, also at 1 rad/s, only, in the opposite direction. So, 1 rad/s positive + 1 rad/s negative = stationary, and there is no axial CF without axial rotation.

That orbital momentum is the product of the orbital angular inertia times orbital velocity. It is the orbital MoI that is being modified by turning the motors on and off. Switching them on halves the orbital MoI. Orbital momentum is conserved, so orbital velocity doubles to compensate.

So we begin with 16 kg-m² of MoI, at 1 rad/s, so we have 16 kg-m²-rad/s of angular momentum, and 8 J of rotKE (again for everyone's benefit, momentum = I * w, and KE = ½I * w²).

Then the motors fire, causing orbital MoI to halve down to 8 kg-m² (check the MoI plot & diagram to see this). This causes velocity to double in response, so we end up with 8 kg-m² of MoI at 2 rad/s, and so solving for ½Iw² we get:

0.5 * 8 * 2² = 16 Joules of orbital rotKE

This is the only KE value that an MoI of '8' rotating at 2 rad/s can have - tho everyone understands this, presumably?

And because momentum's conserved (the cycle's statorless, and gravity's disabled in the basic "200%" sim, so the system has no means of exchanging momentum with its environment), but we've halved the MoI, we've likewise doubled the velocity and associated KE.


So there's no mystery about anything here - it's just basic bog-standard angular quantities. Momentum, and KE.

The reason it's over-unity is because no work has been done in halving the MoI.

Usually, doing so would require physically pulling the orbiting mass inwards, against CF force. The integral of that force times displacement is always precisely equal to the resulting rotKE rise.

Yet here however, we're getting that same MoI decrease, without having to perform any work against axial CF force. We just fire the motors, MoI halves, the orbiting rotors cease their axial rotation and thus we can then perform the radial translation, sliding the masses inwards and so consolidating the dynamic MoI drop caused by the relative co-rotation of the orbiting rotors, into an actual (ie. static) MoI drop of equal magnitude.. without having to perform any work against axial CF!

The masses still experience CF from the orbital plane during the radial translation, however when all four (or any pair, in fact) of these force * distance integrals are added together - as seen in the "net radial F*d" plot - they sum to zero work done.. inbound and outbound CF F*d integrals are mutually self-cancelling!

So the 200% gain is free - no net input work has been performed during the cycle.

Weak analogy, but it's kinda like adiabatic compression - by squeezing that conserved 16 kg-m²-rad/s down into an MoI of '8', we've raised the 'temperature' of its velocity component, or KE. 8 kg-m² at 2 rad/s, by definition, has 16 J - no more, no less. RotKE = ½Iw². Not my doing. Basic classical physics 101.

So believe in physics or don't - the result is what it is. Find the error, or accept the mystery, your call..

It's the very cliche of preposterous claims, what more can i say. At least with magnets you got a little mystique going on there; grey areas, hidden quantities, non-linear inter-reactions etc.. But this shit's just the most basic laws of motion. Force, mass, motion. Momentum and KE. Kid's stuff. How could even i fuck this up?

Cuz it's either a right royal one, or else piss-easy mechanical OU..

Posted By: Duracell

Posted By: Vibrator[span style=color: red]Check Google if you don't believe it[/span][span][/span]- MoI is given by mass times radius squared (mr²), AM is MoI times angular velocity (Iw) and rotKE is ½Iw². These are the ordinary, bog-standard terms - the most basic basics..

... he said ... to the Physics Professor. Ah, well, another perfectly good cup of coffee lost.

Oh well i have come to the right place, then.


Then again, we're talking basics - foundational stuff, that no one should ever forget, but which presumably doesn't get used much after grade school.. But no, you're right - this should be bread & butter to a physics prof..

Reminds me of what Angus used to say. If we had bread we could have bread and butter if we had butter.

Posted By: Vibrator

Posted By: Duracell

Posted By: VibratorCheck Google if you don't believe it- MoI is given by mass times radius squared (mr²), AM is MoI times angular velocity (Iw) and rotKE is ½Iw². These are the ordinary, bog-standard terms - the most basic basics..

... he said ... to the Physics Professor. Ah, well, another perfectly good cup of coffee lost.

Oh well ihavecome to the right place, then.


Then again, we're talking basics - foundational stuff, that no one should ever forget, but which presumably doesn't get used much after grade school.. But no, you're right - this should be bread & butter to a physics prof..

You know that part of Angus his reply that you quoted above to which you replied: “LOL right, not sure what you’re on about here”?

Well, here’s a free tip for you: When a Professor of Physics pays you the courtesy of sticking his head far enough down into your rabbit hole to take a look at your “overunity” spinning things perpetual motion machine free energy simulation and make an observation about it, then you would probably be better served by at least trying to take the time and make the effort to venture far enough out from your rabbit hole in order to attempt to comprehend it than you would by laughing at it and dismissing it out of hand while simultaneously admitting that you do not understand it ...