Newton's third law problem.

[electrodacus]

This is why I show the CAD model of the exact vehicle I built and verified works as I described –– and Electrodacus claims is impossible ––: so that you can examine it and build it or your own version of it, and prove it yourself.  There is absolutely no trickery here.

I want to first mention that I appreciate your long description and I read it at least twice.

I do not need to build the vehicle you mentioned to know it will work and never claimed your device or mine works as shown in many videos.
The question is not if it works or not but how it works.

Both my simpler belt model and your use the same principle is just simple to explain how it works on the model that is easier to visualize.
It is not possible to get rid of energy storage so saying that the string you used is not elastic will not be true as all stings will have elasticity it will just be less elastic than the rubber belt I used.
It is also very likely that the string is not even the energy storage used for your vehicle or not the main one.
For example on the geared vehicle I used (gears instead of the belt) the actual frame of the vehicle was the part that stores most of the energy and you could see how the vehicle body deforms with a regular patterns as energy was charged and discharged.

So the question is the same and in the simplest form I can think of it looks like this


I did not added the force pairs related to gravity as they are not relevant.
In this case the applied force is F1 and all the resulting forces are added in the diagram.
Now if you prefer you can reverse the direction of the treadmill so F1 faces away from F2 to be more similar to your vehicle setup but nothing else will actually change.

So question is in what circumstances the F2 can be larger than F1 to allow the vehicle to be accelerated in the opposite direction the F1 is applied.
The only solution I can see is energy storage so it can be the orange string that is stretched or it can be the green body that is compressed or even a combination of both.
This storing of energy alone will not be sufficient as the energy should be discharged in order to move the vehicle and for that to happen something will need to slip and it is also important that there is a delta between the force needed to slip and the one needed to stick so that energy can be charged and discharged repeatedly.

I actually showed video evidence of what I'm describing but the critique was that vehicle is just not build great and that observed behavior is just some sort of coincidence and not needed.
One thing that can be done is to measure the force needed to move the vehicle and show that is exactly the force needed for the front wheel to slip.

[fourfathom]

While this is an interesting topic (originally "downwind faster than the wind"), I am skipping this discussion because we have already discussed it to death with electrodacus here: https://www.eevblog.com/forum/chat/mess-with-your-minds-a-wind-powered-craft-going-faster-than-a-tail-wind-speed/ and here: https://www.eevblog.com/forum/chat/veritasium-wrong-about-faster-than-wind-direct-down-wind/.  Don't bother trying to explain it to him, unless you enjoy repeatedly banging your head against a brick wall.

[Nominal Animal]

It is one thing to argue with math and diagrams and even animations, but a completely different thing to show a model one can build and examine, and build the proof with their own hands.

Someone built a model before, but Electrodacus simply rejected it and said it couldn't possibly work without including energy storage in the explanation.

Oh, I missed that.

This one, with a worm and a pinion, eliminates the energy storage argument.  The worm can turn the pinion, but the pinion cannot turn the worm at all: it immediately locks up.  Any energy storage would therefore have to be in the spool axis.  Because the spool stops turning immediately when you stop pulling on the thread (which also means the trike immediately stops), there is evidence of no energy storage.

Attached are couple of real-life photos of it.  (I removed the front black thread guide block for these, so you can see the structure better, but otherwise it matches the LeoCAD model.)

Both my simpler belt model and your use the same principle

No, they absolutely do not.

Your model uses a gearing ratio which means no stable motion is possible.

This model uses a gearing ratio where stable motion is possible, and indeed, if you pull the thread at a constant velocity, the vehicle travels at a constant velocity as well.  If you relax the thread, the motion stops immediately.  There is no energy storage.  Even the forward momentum of the vehicle itself does not and cannot act as a energy storage, because of the worm-pinion gearing: the forward momentum and wheels cannot feed back energy to the worm.  Lego worm gear is steep, and immediately locks up if you try to back-drive the worm with the pinion gear.

Your model requires energy storage because of the inverse gearing ratio.  Mine works completely without any kind of energy storage, for the reasons I described earlier.

It is not possible to get rid of energy storage

Yes, it is.  I described how, and implemented it in real life.  If you think about how a worm-pinion gearbox works, and demonstration shows the worm side (spool side) does not retain any energy, because as soon as you relax the thread, the spool stops turning, and that immediately stops the trike.

In particular, the vehicle does not move if you just repeatedly tug on the thread.  You need to pull consistently, without any oscillation, to make the vehicle move.

Because the spool, worm, and pinion are in a very rigid structure above the driving wheel axis, any flex in the rest of the structure is irrelevant.

You cannot consider the moment of inertia in the wheels as energy storage, because it cannot be back-fed over the worm-pinion.  It is just rotational inertia in the wheels.  To prove this, switch to smaller, more lightweight wheels (thus less rotational inertia), and the vehicle will move even easier!
(The rotational inertia in the driving wheels means you must pull consistently, as dropping the pull rate even slightly will lead to lockup, because the wheels will try to drive the worm via the pinion, which leads to the worm-pinion locking up.  With less rotational inertia, you can drop the pull rate slightly without lockup, because the wheels won't freewheel as much.)

we have already discussed it to death with electrodacus here: https://www.eevblog.com/forum/chat/mess-with-your-minds-a-wind-powered-craft-going-faster-than-a-tail-wind-speed/ and here: https://www.eevblog.com/forum/chat/veritasium-wrong-about-faster-than-wind-direct-down-wind/.  Don't bother trying to explain it to him, unless you enjoy repeatedly banging your head against a brick wall.

Oh.  Thanks.  I avoided those threads, because I knew a physics view would be lost in the noise in such a thread.  And the physics view is that whenever there is wind with respect to the vehicle, energy can be extracted; and no Earthly wind is stable enough for the switchover (when vehicle goes exactly at downwind speed) to last for any appreciable time, so it is just a matter of efficiency and reducing losses.

It seems I was indeed trapped in a fool's errand, because I did not realize this thread is just a continuation or restatement of those. 
Having played with Lego Technic extensively as a child, I discovered many non-intuitive powering mechanisms on my own, so I know how unintuitive many of them are; I spent many tens of hours just examining the mechanisms.  Here, I just didn't associate the treadmill or "providing linear mechanical power opposite to the desired movement" with the faster than tail wind stuff at all. 

[bdunham7]

And the physics view is that whenever there is wind with respect to the vehicle, energy can be extracted

Indeed that is what is apparent at first glance, but it isn't actually true, at least not if you mean with respect to the body of the vehicle.  What is actually needed is simply any reference (the ground in the actual vehicle) and a wind relative to that reference.  The point at which the wind speed equals the vehicle body speed isn't really that special at all because the action of the wind on the body is not the main event.

[electrodacus]

No, they absolutely do not.

Your model uses a gearing ratio which means no stable motion is possible.


Yes, it is.  I described how, and implemented it in real life.  If you think about how a worm-pinion gearbox works, and demonstration shows the worm side (spool side) does not retain any energy, because as soon as you relax the thread, the spool stops turning, and that immediately stops the trike.

In particular, the vehicle does not move if you just repeatedly tug on the thread.  You need to pull consistently, without any oscillation, to make the vehicle move.

Your vehicle is in no way different in functioning principle.
The gear ratio while larger on your machine it is not different.

On my vehicle the wheels with the smaller pulley is the generator wheel (input) and in your case the input is the spool.
If you can measure the tension in the thread (a small strain gauge load cell connected to an oscilloscope) you will be able to see the charge discharge cycles.
It will obviously look smooth the same way the vehicle I showed looks smooth in real life no slow down video and a bit higher speed when the vehicle kinetic energy storage smooths things same way as adding a capacitor in an electrical circuit will do.

Look at this zoomed in gear and slowed down video 120FPS using my soldering microscope https://odysee.com/@dacustemp:8/120fps24:9
See at around second 9 in the video the gear changing direction for a few video frames imperceptible with the naked eye.  That is the point the energy was discharged and that will repeat at regular intervals. The video is upside down but not relevant.


The point is that you are unable to explain how it works without energy storage and that is my main question. There are plenty of variants of this same vehicle and all of them work the same. For some strange reason you think that your vehicle is different than mine when it is not and no the gear ratio is not reversed as there is no such thing (you just rotate my vehicle 180 degree and it what you are asking witch is the same thing).
Also if I move the paper that is under the back wheels instead of the front the vehicle works exactly the same as it is irrelevant what surface moves relative to the other or in what direction.

In the case of your vehicle if you spool the thread in one direction you get the same vehicle I have and if you spool in the other direction you get the version I will have if I were to twist the belt like an infinity sign so no longer a locked gear and vehicle will move in the direction of the applied force.

[electrodacus]

And the physics view is that whenever there is wind with respect to the vehicle, energy can be extracted

Yes energy can be extracted but you are confusing energy with power.
Power needed to drive against wind direction (upwind) is equal with the power wind already exert against the vehicle in the opposite direction.
So if based on vehicle area and wind speed 100W act against the vehicle then vehicle needs 100W + friction losses to drive at any speed against the wind direction.
So the only way to apply more than 100W is to store energy and then release it.



Driving at say 30m/s with no wind will have the same power required to overcome drag as driving at 10m/s in a 20m/s head wind.
So you agree with this above statement ? Because is not that is the the main disagreement that we have and this while not easy can be tested.

[Circlotron]

A simplified example is a pair of wheels with almost as large a pulley in between, with a thread rotated on the pulley.  What happens when you pull the thread?

If you start examination at the zero-movement state, you'll find that the angle at which the thread exits the spool, with respect to gravity down, largely determines whether it starts moving or not.  If you pull the thread exactly level, the forces do not leverage the wheel to turn so that it would travel opposite to the direction the thread is being pulled to.  If you pull the thread slightly upwards or downwards from level, the forces are no longer balanced, resulting a small torque on the wheel, so it'll start traveling opposite to the direction the thread is being pulled to.  If you pull the thread nearly vertical, the torque is maximized, and it is easiest to get the wheel to travel (away from where you are pulling the thread)

Underline added by me.
I tried this experiment a while back with a roll of solder that had several layers used. The unused solder was about 5mm down from the cheeks of the plastic spool. With the solder extending parallel to the table top and coming from the underside of the roll you could pull the solder and it would roll up in a curious sort of way. It almost looked like an optical illusion. Something like you could pull the solder 20mm and the roll would move toward your hand 150mm, winding the solder back onto the roll as it went. Best results were when the extended solder was halfway between the two cheeks so the spool wouldn't pull to one side.

A roll of solder is a good choice because it is reasonably heavy so the edges of the spool can have a grip on the table top without slipping, and everybody who's anybody has a roll of solder to try it with.

[electrodacus]

Something like you could pull the solder 20mm and the roll would move toward your hand 150mm, winding the solder back onto the roll as it went. Best results were when the extended solder was halfway between the two cheeks so the spool wouldn't pull to one side.

We are discussing about the opposite of your experiment.  You pull the sting and the roll will go away from your hand.

[Nominal Animal]

And the physics view is that whenever there is wind with respect to the vehicle, energy can be extracted

Indeed that is what is apparent at first glance, but it isn't actually true, at least not if you mean with respect to the body of the vehicle.  What is actually needed is simply any reference (the ground in the actual vehicle) and a wind relative to that reference.  The point at which the wind speed equals the vehicle body speed isn't really that special at all because the action of the wind on the body is not the main event.

Sure.  If you don't want to limit to any particular mechanism, then "wind with respect to ground" is better and more accurate.

(I was thinking of devices without any energy storage, which are much more limited.  My one-track mind and all.  I now wish I had written "respect to the ground" instead.)

Even a simple mechanism, say a VAWT (vertical axis wind turbine), which extracts energy from wind in any direction perpendicular to its axis, can be made much more interesting by using say three of them rotating around a common vertical axis.  As long as the common axis rotates, all three experience a different relative wind speed and direction (relative to its own axis, that is) –– unless the wind is actually a vortex around that common vertical axis.
(In this case the rotation around the common vertical axis can be considered energy storage, but it is a consequence of the mechanism.)

Such mechanisms are very interesting to model and build, but I agree, it is not useful to discuss their theoretical properties in a forum like this: the signal to noise ratio is too low, with noise generated by well-meaning people basing their argument on intuition and experience with dissimilar devices, instead of physics.


As to the simplest possible example of the pull-thread-thing-moves-the-other-way, just put a spool on an axis, and make two straight rails for the axis.  If you pull the thread horizontally below the rails, the pulley will go in the opposite direction.  Just make sure the axle and rails have sufficient friction, so that the axis rotates instead of sliding.

With a heavy spool, the friction of the spool to the ground is so good that instead of sliding, pulling on the thread (or solder wire) so that it comes out from below, will actually cause the spool to rotate towards you, even when that causes the spool to rewind itself; and the axis of the spool will travel faster than you are pulling on the thread/solder.  This is what Circlotron observed.

[Nominal Animal]

And here is the simplest, most intuitive treadmill example I can think of, using Lego Technic.

If you rename the attached treadmill.txt to treadmill.ldr, it too can be opened in LeoCAD.  I omitted two rack pieces, and cut the long holey bar short, so you can see what is happening better.

If you turn the blue handle clockwise, the upper surface of the treadmill chain goes right, but the gearwheel rotates counterclockwise and moves left.
If you turn the blue handle counterclockwise, the upper surface of the treadmill chain goes left, and the gearwheel moves right, rotating clockwise.

This is not a "locked gearbox", because the geared wheel can move horizontally.

The racks and chain are not necessary for correct operation, they just provide lots of friction.  The same works even with thread and smooth wheels, as long as you have sufficient friction that nothing slips.

[electrodacus]

This is not a "locked gearbox", because the geared wheel can move horizontally.

The racks and chain are not necessary for correct operation, they just provide lots of friction.  The same works even with thread and smooth wheels, as long as you have sufficient friction that nothing slips.

It is a locked gear and I already did the experiment see video https://odysee.com/@dacustemp:8/gear-slow30p2:9
And here is the slow motion and zoomed bit unfortunately is upside down but around second 9 you can see the energy stored is released https://odysee.com/@dacustemp:8/120fps24:9

[Nominal Animal]

No, electrodacus.  You're letting your preconceptions override your search for the facts.

This is the complete model of the situation:


Let t be the surface velocity of the treadmill, positive right.
Let c be the velocity of the center of the gears, positive left.
Let R be the radius of the treadmill gear (blueish), and r the ground gear (pale yellow-orange).
Finally, let φ be the angular velocity of the gears.

For the ground gear to not slip, we need φ=c/r.
For the treadmill gear to not slip, we need φ=(c+t)/R.

Combining the two rules, we have an equation that holds whenever the gears do not slip: c/r=(c+t)/R.  Solving this for c yields c=t*r/(R-r).

The only impossible situation is when the two gears are the exact same size.  This is the locked-up gearbox case, where non-slip motion is not possible.

In the case where r<R, c will be positive, and the center of the gears will move in the opposite direction compared to the surface of the treadmill.

Circlotron observed the situation when R<r, about R≃0.867r.  Then, c=t*(-7.5).  Because c is negative, it travels in the same direction the surface of the treadmill travels (or equivalently the wire is pulled).  Because the magnitude of the ratio is so large, the forces are such that you need spool to have excellent traction (stiction, static friction) to ground: a heavy soldering wire spool is an excellent test case.
Then, when you pull the wire towards yourself, the spool will also rotate towards yourself but much faster.  When you pull the wire 20mm, the spool will travel 20mm×7.5 ≃ 150mm, just as Circlotron described.  (I wonder if circlotron agrees that the diameter of amount of solder in their spool was about 0.867 of the outer diameter of the spool?  In any case, if you happen to have a heavy spool yourself, you can easily check the math here.)

Although I called t and c and φ velocities, the math stands exactly the same if you consider them displacements instead.  That is, when the treadmill surface moves right by t (left if negative), the angle of the axis of the gears changes by φ, and the spool/axis of the gears moves left by c (right if negative).

There is no energy storage needed.  You can start from a standstill, move the treadmill surface by a fixed amount, and measure how far the spool/axis of the gears moved.  If the spool/gears were heavy enough with enough friction/traction/stiction, so that there was no slippage, the above formulae will hold.

There is no strangeness related to energy conservation either.  If you do the heavy almost-full spool test, you'll find that it is quite hard to pull the wire.  In other words, it is the treadmill that provides all the energy here, at every instant in time.  It will all be spent in the friction/traction/stiction, if you do the test from standstill to standstill.  All pure mechanics, no slapstick, no aether, no fancy theories.  Plain ol' classical mechanics here.

Sizes and ratios do matter in practice, though.  For example, if your heavy spool is 99% full (meaning, the diameter or radius of the wire in it is 99% of the diameter or radius of its outer edges), the ratio is 1/(0.99-1) = -100.  This means that every millimeter you manage to pull the wire, the spool will travel 100 mm.  It is unlikely that there is enough friction to see this happen; instead, the spool will slip.  So, to see the phenomena better, use a spool with somewhat less wire.

I so wish BigClive would try this.  He's got good cameras, nice bench setup, and suitable spools at the top of his shelves.  Or maybe Dave would?
Me and cameras don't mix too well.  It does look funky, and is a perfect example of how our intuition can lead us astray, which is the reason I answered to this thread in the first place.

[IanB]

I so wish BigClive would try this.  He's got good cameras, nice bench setup, and suitable spools at the top of his shelves.  Or maybe Dave would?

There's really no point.

You know that thing children do, when they are playing a game and about to lose, they find some way of cheating so they can try to avoid the outcome? Electrodacus is playing that game here. There is no evidence you can provide, no experiment anyone can perform that will persuade him, because he will just come up with some kind of nonsensical word salad to dispute the result.

Notice how he never does any analysis himself, never shows any equations, but always tries to make other people do the work? It's a game for him, trying to make people jump to his command, and then getting satisfaction from the "power" that gives him. As I said above, this has all the signs of sociopathic behavior. It is really best not to enable it.

[electrodacus]

No, electrodacus.  You're letting your preconceptions override your search for the facts.

This is the complete model of the situation:

Let t be the surface velocity of the treadmill, positive right.
Let c be the velocity of the center of the gears, positive left.
Let R be the radius of the treadmill gear (blueish), and r the ground gear (pale yellow-orange).
Finally, let φ be the angular velocity of the gears.

I did not quote everything just to keep it readable but I read all your repay in details.

I mentioned before but while this mechanism looks simpler is more complex than the one with the belt.

When R=r the gear is locked as you already mentioned.
When R>r the gear is still locked as nothing was changed just the size of the gears.

You can have a working gear box with a gear ratio of 1:1 so the gear ratio is not what makes a gearbox locked or unlocked.

Set the speed of the player at 0.25x and pay close attention to what happens https://odysee.com/@dacustemp:8/gear-slow30p2:9

It is irrelevant witch of the two surfaces move the system will work the same way.

The reason it works has to do with the shape of the tooths on most gear as they allow the gear assembly to lift up when you apply a force.
So energy storage in this case is gravitational the wheel is lifted when charging then falls back when discharged.
If you make custom gear's with the shape of the tooth so that it will not allow this lifting of the gear you can eliminate the energy storage and you will no longer be able to move it.
With typical gears as the ones in my video the horizontal applied forces allow the gear to lift up and thus store potential gravitational energy.
If you push a triangle against an upside down triangle horizontally the triangles will slip against each other and lift up. So charge the shape of the tooth's to eliminate this and you will see that it no longer works.

[Nominal Animal]

I so wish BigClive would try this.  He's got good cameras, nice bench setup, and suitable spools at the top of his shelves.  Or maybe Dave would?

There's really no point.

You misunderstand.  I meant that as a short video, it would be interesting, exactly because with sufficient weight and thus friction, the spool does behave unintuitively.  Moreso because we can't "see" how hard one must tug on the wire to get it to move; it looks unintuitive.

Like the trick with rails that become wider as they go up, and how a suitable double cone seems to roll uphill along such rails.  Or how you can accidentally power an IC via an I/O pin.

Electrodacus is playing that game here. There is no evidence you can provide, no experiment anyone can perform that will persuade him, because he will just come up with some kind of nonsensical word salad to dispute the result.

True; I've lost all hope of being able to help electrodacus here.

Yet, there is still a possibility that someone else reading this thread –– say, arriving here via a web search –– might start thinking about whether they just assume things because they're intuitive, and learn to question their intuition, and maybe even how to find out for themselves.  If that happens, all my effort has not been in vain..  My last couple of posts have been trying to round the topic up in case that does happen.

If I were still believing I might be able to help electrodacus see, I would have added another figure that contains the force vectors.  The key vectors would obviously be the two torques around the gear axis, because once one realizes their importance on how this system works, everything else including friction/stiction/traction becomes obvious and straightforward.  But no, I haven't drawn such an image, and will not.  Anyone truly interested in the subject can use any (classical) mechanics 101 book, and draw this themselves, and work it all out.  Or indeed grab some Technic Lego, and build working models, and compare their behaviour to what I described.

[james_s]

There's really no point.

You know that thing children do, when they are playing a game and about to lose, they find some way of cheating so they can try to avoid the outcome? Electrodacus is playing that game here. There is no evidence you can provide, no experiment anyone can perform that will persuade him, because he will just come up with some kind of nonsensical word salad to dispute the result.

Notice how he never does any analysis himself, never shows any equations, but always tries to make other people do the work? It's a game for him, trying to make people jump to his command, and then getting satisfaction from the "power" that gives him. As I said above, this has all the signs of sociopathic behavior. It is really best not to enable it.

Just put him on your ignore list, one less source of noise.

[IanB]

If I were still believing I might be able to help electrodacus see, I would have added another figure that contains the force vectors.  The key vectors would obviously be the two torques around the gear axis, because once one realizes their importance on how this system works, everything else including friction/stiction/traction becomes obvious and straightforward.  But no, I haven't drawn such an image, and will not.  Anyone truly interested in the subject can use any (classical) mechanics 101 book, and draw this themselves, and work it all out.  Or indeed grab some Technic Lego, and build working models, and compare their behaviour to what I described.

The interesting and important thing about the analysis of kinematic structures, is that forces or force vectors are not required in the analysis, in fact trying to use forces just makes the system harder to understand.

You have a system of rigid elements connected at various points by pivots or hinges, or in the case of wheels or gears the contact points. Since all the elements are rigid, there are equations involving only (x, y) coordinates that relate all the points in the system. All you have to do is to move one point, and all the other points will move in unison as governed by the connections. It is a pure problem of spatial geometry, with no force, energy, power or momentum involved in the analysis. (For example, consider a pantograph.)

[electrodacus]

It is a pure problem of spatial geometry, with no force, energy, power or momentum involved in the analysis.

That is your problem. It is not just about geometry.
With that even 1:1 gear will work fine.
A 1:1 will not work even in theory and close to 1:1 will not work in practice due to losses.  The higher gear ratios work due to energy storage but you can not know that if all you look is geometry. 

[PlainName]

Why is this started up again, electrodacus? No-one can change your mind, and you can't change the laws of physics or the opinions of anyone not you. That's been amply demonstrated in more than one lengthy thread previously.

So... why did you start this again? The only reason I could think of if someone else had done so is because they still couldn't solve the problem and wanted some help to clear up some points. But you don't - you know what you know and nothing is going to change that. Even if there was something you were unsure of, you wouldn't accept what anyone explained or demonstrated anyway unless it fit your already decided solution.

[Nominal Animal]

If I were still believing I might be able to help electrodacus see, I would have added another figure that contains the force vectors.  The key vectors would obviously be the two torques around the gear axis, because once one realizes their importance on how this system works, everything else including friction/stiction/traction becomes obvious and straightforward.  But no, I haven't drawn such an image, and will not.  Anyone truly interested in the subject can use any (classical) mechanics 101 book, and draw this themselves, and work it all out.  Or indeed grab some Technic Lego, and build working models, and compare their behaviour to what I described.

The interesting and important thing about the analysis of kinematic structures, is that forces or force vectors are not required in the analysis, in fact trying to use forces just makes the system harder to understand.

I know and agree.  If you look at my posts in this thread, I've said so myself, and instead described the system behaviour in terms of surface velocities or displacements in the math snippets.

If we had managed to progress to the "okay, I now see how this behaves so; but when and how does the slippage I saw occur? And why didn't my original approach describe the system?" stage, then we could have moved on to the forces.  Not to describe the behaviour of the system, but to describe why any simplified force-based description fails.  It is a pedagogical pattern that has often worked well: you look at the situation from a completely different approach, and only if/when you finally grasp the behaviour, you close the loop by examining how and why the original approach failed.

Here, you would only care about the forces if you wanted to find out the limits where slippage occurs; the coefficients of friction and system weight that are required for no-slip operation at a given gear ratio.  Starting from that is silly.

Where the insistence of energy storage being involved here stems from, I can only imagine.  There is no need for one.  The same math is valid both at standstill and at any velocity, continuously.  Even if one were to examine the forces, one would see they balance perfectly at each instance; with the only "energy storage" being the linear and angular momentum in the "car" or "spool", both perfectly aligned in the direction of travel.  No vertical motion at all, unless slippage occurs; and the systems I've described are explicitly in the no-slip cases.  You can make all sorts of things "work" if they slip a bit, but these ones do not need slippage or energy storage to behave as I've described.

[electrodacus]

Why is this started up again, electrodacus? No-one can change your mind, and you can't change the laws of physics or the opinions of anyone not you. That's been amply demonstrated in more than one lengthy thread previously.

So... why did you start this again? The only reason I could think of if someone else had done so is because they still couldn't solve the problem and wanted some help to clear up some points. But you don't - you know what you know and nothing is going to change that. Even if there was something you were unsure of, you wouldn't accept what anyone explained or demonstrated anyway unless it fit your already decided solution.

I need to share the world with all of you. So it is in my interest that people understand how the world works as I depend on that.

What you (all) are claiming violates energy conservation so since that is not possible the explanation is wrong.

[electrodacus]

Where the insistence of energy storage being involved here stems from, I can only imagine.  There is no need for one.  The same math is valid both at standstill and at any velocity, continuously.  Even if one were to examine the forces, one would see they balance perfectly at each instance; with the only "energy storage" being the linear and angular momentum in the "car" or "spool", both perfectly aligned in the direction of travel.  No vertical motion at all, unless slippage occurs; and the systems I've described are explicitly in the no-slip cases.  You can make all sorts of things "work" if they slip a bit, but these ones do not need slippage or energy storage to behave as I've described.

I guess you did not read my reply to your latest comment.
There is slip with gears also due to the gear shapes you are pushing an upside-down triangle on to another triangle so the two triangle will slip past each other lifting the gear that in this particular case is representing the vehicle.
So there is both slip and energy storage in the gear vehicle example.


And if you want to know about why energy conservation is relevant here then let me explain.

Any gearbox (witch is what this vehicles are) have an input and an output.   The output power of the gearbox can not be higher than the input power and this is what you are all claiming without realizing you do.  The energy storage and stick slip hysteresis is necessary for this to work while not violating the energy conservation law.

Fact:
Power needed to overcome drag for a vehicle driving at 30m/s with no wind is exactly the same as for the same vehicle driving at 10m/s in to a 20m/s head wind.

[PlainName]

Fact:
Power needed to overcome drag for a vehicle driving at 30m/s with no wind is exactly the same as for the same vehicle driving at 10m/s in to a 20m/s head wind.

And 40m/s with a 10m/s tailwind, right?

[electrodacus]

Fact:
Power needed to overcome drag for a vehicle driving at 30m/s with no wind is exactly the same as for the same vehicle driving at 10m/s in to a 20m/s head wind.

And 40m/s with a 10m/s tailwind, right?

Yes.

[AVGresponding]

Where the insistence of energy storage being involved here stems from, I can only imagine.

My (admittedly cynical) guess is a desire to jump on the novel energy storage solution/harvesting bandwagon...