Crazy as can be wheel concept

[Fletcher]

By design the weights MUST be hanging somewhere on the rim of the large wheel or on the peg inside.

Look again at Wubbly’s sim. From start to 46 second running time, the wheel and the weights are in balanced state.

Presumably during that time, data were being added for the start of run, including engine activated, external force added to help wheel to accelerate.

Just after run is pressed, two weights on the counter-clockwise drop with a bang counter-clockwise side, most like negating the external energy provided to accelerate the wheel.

...............

These pictures show blatant mispositioning of weights in Wubbly's simulation.

Can you find which weights?

This mispositioning of weights happens every 45 degrees turn of wheel, which reduces the clockwise torque in the simulation.

Raj .. up to 46 second mark Wubbly is showing the final phase of the building of the simulation. He has been constructing it but hasn't run the sim until he clicks Run Sim shortly after. That's when objects free to move find their positions of least GPE. When the motor drive is activated the sim immediately starts revolving at a constant speed CW. He then subsequently turns the motor drive On and OFF and adjusts the rotation speed to see if it has any tendency to carry on rotating, or accelerate, from a different base rotation rate CW. At the end he reverses the motor drive to see if will run better backwards.

In your screen grabs you show the sim at 1.13 secs, 1.50 secs, and 1.53 secs. The sim is running at real time.

You will have noted earlier that Wubbly built the sim with a radius of 1 meter. He included 3 variables. A motor drive that can be turned ON and OFF, and can also be set to a negative or positive value, or to zero (which is the same as turning it OFF). Rotation rate is in degrees per second i.e. at 1.13 secs -40; at 1.50 secs -60; at 1.53 secs -70. These, with a little pencil work, correspond to RPM's of 6.67; 10.0; and 11.67.

Note that the other two variables are background wheel mass of 5 kgs. And each weight at 1 kg. He keeps the ratio of background to weights close so that the inertia of the background wheel is not too great, otherwise if it were very massive it would tend to mask the effects of the transitioning weights (smooth things out). With a low mass background wheel movements are more 'jerky' and apparent. He could of course set the masses to anything he wants.

The next thing is he uses rods as items 4 (pendulum) of your original drawing. You make an NB that they could also be strings. He chose to use stiff rods anchored by pivot to your peg 3 since you allowed that. He also says he set elasticity to zero, plus all frictions including air frictions to zero. That means the ropes have no spring like effect inherent in them i.e. they don't stretch or bounce. IOW's you don't lose any energy from deformation and as heat for the best possible energy conservation result. Very close to how a real rope or steel cable would behave. N.B. everything else like rods and strings are massless and incidental to the exercise.

..........................

Now that you know he used rods and not strings, and that main objects have inertia we can look at what you are saying.

Firstly a rod with weight shares its weight with both the wheel rim (via the stretched string attachment) and the peg 3 (via the rod). IOW's the weight load is shared between the stationary (fixed in space second Center of Rotation) peg 3 and the revolving rim. This sharing is dependent on the relative angles made. For example when a rod and weight is at 12 o'cl and 6 o'cl all the mass is supported by the peg 3. At other positions it is shared out. Trigonometry.

I am guessing that you think the blatant misplacement of weights is just after 12 o'cl on the CW rotations. You picked one screen shot where the strings 6 and 7 are both slack i.e. the weight is transitioning forward relative to the wheel. In the others I am guessing you think the fall is delayed too long which you think wouldn't happen in the real world ?

All I can say is that objects have mass and therefore inertia. Which is a tendency to remain in motion both in magnitude and direction until acted upon by an external force. The Centripetal force of the rods is what provides that force to cause an acceleration of the weights and follow a curved transition path limited eventually by the strings etc. But that is not instantaneous, and takes some micro time. You see that in the sim as a slight hesitance or delay in movement of the rod slightly past 12 o'cl. Actually it is just latency in action. All movements are subject to some time interval. The sim factors ALL these things.

If we have not identified your problem with the sim please spell it out so that your concerns can be considered. A sim is a substitute for a real world build, and is usually a pretty good approximation if done carefully as Wubbly has done. The beauty of the sim is it can be tweaked to align with real world results if there is an explainable anomaly or divergence in behaviour to consider.

ETA : Wubbly reverses the sim direction near the end and the latency (and inertia) of falling weights past 12 o'cl is more visually pronounced, imo.

[raj]

THANK YOU ALL for your sustained help.

Raj

[Fletcher]

You edited your above post.

Craziest than this wheel concept, I have never seen in my life before.

1. a drum wheel1 of 8 units radius on axle2.

2. a horizontal fix peg/pivot3 two units vertically below axle2.

3. pendulums4 of 4 units length and weights/bobs5 swing separately on peg/pivot3, connected to strings6 and strings7 at 45 degrees intervals on rim of wheel1, and hang on strings6 of 8 units length on the clockwise side and on strings7 of 6 units length on the counter-clockwise side of axle2,

N.B: pendulums4 can also be simply strings of 4 units length.

All weights/bobs are hanging, swinging and their gravitational force are acting on one and the same wheel, clockwise and counter-clockwise, making finding gravitational torque on the wheel that much easiler.

WHAT to make of this is anyone guess.

For me, I can see positive sign of a working wheel, an intricate system of only strings and weights rotating a wheel

Are you saying your peg3 is NOT fixed as per your drawing accompanying the above description ?

It appears the peg 3 in your build is attached to the wheel support ?

If it is fixed 2 units below axle 2 then the wheel has two fixed Centers of Rotation to be accounted for in your analysis.

[raj]

Be it axle4 of small wheel3 or call it simply pivot 3 without small wheel, vertically 2 units below axle2 of larger wheel1 in nearest separate vertical plane.

White strings swing on fix pivot3.

Raj

[Wubbly]

Marchello, that overlay was impressive and you cranked that out in a matter of minutes!

Fletcher, excellent description of the simulation.

Raj,
Your picture is what the simulation showed, except I used rigid rods instead of strings at peg3.

Here are two simulations of your wheel: https://youtu.be/tIwylzT4CqI

They start from rest with the wheel locked, and a few seconds in the lock is removed and the wheel is free to rotate.

Part 1 uses a rigid rod and two strings attached to each weight.

Part 2 (with the dark background) substitutes a string at peg3 instead of a rod.

In both cases there is excess torque in the static start position.

In both cases the excess torque does not create continuous wheel rotation.

This is the same simulation as before, but without the motor (which simulated a person manually spinning the wheel then letting the wheel coast).

Static analysis of torque is insufficient to determine dynamic motion of the wheel.

[raj]

Wubbly , you have done a great job for free for me.

It’s an eye opener. Now I know what need to be done to stay on tract.

I cannot thank you enough.

Raj

[Wubbly]

Keep learning to the end Raj.

[raj]

DON'T you, Wubbly?

DON'T all learn something new, when they see something they never seen before, when they hear something they never heard before.

TELL ME, IS THERE AN ALL-Knowing person in this world?

YES, I'LL keep learning anything new of interest, till I DIE, like how to keep safe
from covid-19

Raj

[WaltzCee]

Woo! Wubbly got a promotion! Well deserved. :)

YES, I'LL keep learning anything new of interest, till I DIE, like how to keep safe
from covid-19

Speaking of the Wuhan Red Death, l heard WHO is investigating the possibility of
reinfection. Evidently it's a distinct possibility and it can come back the 2nd time with a
vengeance. What an amazing weapon. Better than a nuke and much easier to get into a
country.

I think one of the horsemen of the apocalypse (the pale horse) has saddled up.

[Georg Künstler]

Hi Raj,
I can not help you with such simulations, which have now provided for you from other Besslerwheel enthusiasts.

Nevertheless it should drive the thinking in the right direction.
Look to a construction which is self starting and self sustaining, then self accelerating.

The uncontrolled swinging/oscillation will kill the first advantage.
You still have a center axis of rotation.

What we need is an off center rotation. I myself have made such constructions, but with no success because I get an uncontrolled oscillation.

Your construction inspired my also to use strings, ropes maybe this version is now better than the versions before.

One ounce here or there will not stop the unbalance, I will send you a picture of the construction. The uncontrolled swinging is now under control.
Friction should not be the problem to stop it.

All the Best to you Raj.

[Wubbly]

Yes Raj, we are all learning to the end. I learned a lot this past year. I learned how to roast sweet potatoes at 375 degrees for 45 minutes with just the right amount of seasoning. I learned how to pressure cook cod so it is fork tender. I learned how to pressure cook chuck roast so it falls off the bone. <Insert shameless Instant Pot plug here>. I learned an old man can read the Harry Potter books and enjoy them. I did NOT learn how to plant grass though. Most of it died. I'm still working on that one. And I have many more things to learn before I get off the planet and transition out of these three dimensions with their energy conservation laws - well, at least at the unclassified level.

[ME]

Your picture is what the simulation showed, except I used rigid rods instead of strings at peg3.

The blue weight (XR4_v1d.jpg) is in a similar position as was designed.
Only a very sturdy string could keep it up in that position.
Isn't Raj just flexing goal posts here?

I learned how to roast sweet potatoes at 375 degrees for 45 minutes with just the right amount of seasoning.

You can brag, but 0.023 RPM is not that impressive.
Unless it's an auto-roasting potato engine.
:-)

[Wubbly]

Good catch Marchello. That is a very stiff string

Raj,

Here's your string wheel with an input slider for "string8".

All your given lengths are divided by 8, so your string8 would have an initial length of 1 meter.

The user can modify the length of the string using the input slider. A length of 0.875 would be equivalent to your length of 7 units. (7/8).

There are added subtitles that explain what is happening.

If the motor is turned on with a velocity of 0, it locks the wheel. When the motor is turned off with a velocity of zero, it unlocks the wheel.

In the end I turn the motor on to (-10 degrees/second) to force the wheel to turn slowly.

At higher angular velocities it causes the weights down around 6 o'clock to look like they are out of place so I showed the motor at a low angular velocity.

https://youtu.be/OrCbzIBrZlU

[Fletcher]

Point of Order ;7) I could be wrong. String8 is actually String6 ?

I think it is important to make this further point, about wheel analysis potential in general, which is relevant to Raj's string wheels IINM.

If you have just one fixed Center of Rotation (CoR) which is the central axle for a wheel (or pivot, or fulcrum, for an oscillating device) then analyzing potential Net torque in different wheel positions using the STATIC Turning Moment's (TM's) method is generally quite perfectly adequate and revealing. There may be subtle behavioural differences for the DYNAMIC situational analysis, especially if forced to revolve fast as Centrifugal forces and Latency come into play etc. These are tedious to hand calculate accurately without a sim.

If you have more than one fixed CoR/axle then STATIC TM's analysis can be misleading and has to be modified by use of trigonometry (math), which is a more complex calculation. Otherwise, Dynamically the wheel will be subject to the same constraints of motion as the 'one fixed axle' situation above.

I think Raj's build did accurately reflect the wheels torque potential. And while he distrusted his materials and build skills he was too hard on himself. The empirical evidence was there, just had to be objectively understood so it's lessons could be absorbed.

[Wubbly]

Yes, Raj's string 6 is my string8 in the code (because it's 8 units length normalized to 1 unit),
and his string7 is my string6 in the sim code (because it's 6 units length divided by the normalization factor of 8).