Gravity Wheel

[Calloway]

One interesting follow up I would like to make is alot of the pendulum weight is being transferred to the slider weight extension glove at the 2 o'clock position using this method. This provides continued cw rotation until the slider reaches the 180 degree horizontal line. But by then the slider pair has moved right and has released the pendulum. I would think this could be fairly easy to verify by sim imo. Cheers

[Calloway]

This design just won't leave my thoughts. After leaving it alone for quite awhile, I have a new idea about it. The backdrag from the pendulum weight hitting the slider weight pair was too much. I need leverage to start the slider weight pairs moving.

New idea.
I will move the pendulum mounts down towards the slider weight tracks 22.5 degrees from 45 degrees. I will then replace the string pendulum with a stiff shaft pendulum.

This will drop the pendulum weight below the slider weight pair and allow the shaft to contact and push the slider weight. Clearance will be checked to clear the slider pair and axle from the pendulum weight. I probably want the pendulum shaft as long as physically possible to get all the available leverage I can get. I will start with just 2 pendulums at 180 degrees apart to see how this reacts and go from there.
Cheers

[Calloway]

I'm sort of embarrassed to write this post, but I need tell the group what happened. I moved the pendulum mount down to 22.5 degrees. I seen quickly that the timing was far too late. (Called Latency by ME which is correct! lol) I want to prevent coasting into the next power stroke. (Silent) So I moved the pendulum mount in about 2" keeping it on the segment line and then the pendulum weight would contact the slider weight at about 8:00 o'clock which is what I wanted. I still had backdrag at times and got to looking closer and found the slider block was binding on the shaft which was previously unnoticed by me. When I first purchased these blocks they had roller bearings in them which were fairly tight to the shaft. I removed these ball bearings and installed the plastic races back in the slider blocks to keep clearance at a minimum. WRONG! These plastic races when cocked slightly were acting like a brake and were dragging on the shaft at times fooling me into thinking it was backdrag from the wheel. Well it was backdrag, but not because the pendulum weight couldn't push the slider. I removed the plastic races and damm what a difference. Backdrag can now quickly be seen by watching the string pendulum weight closely. If the string moves out of vertical at any time and by any amount, backdrag is detected. I did notice a slight amount with a 6 oz weight. I changed the weight to 1 lb and backdrag disappeared. Smooth as silk. (This is with one slider block and rail) A correct differential has to be obtained between the slider blocks and the pendulum weight to eliminate backdrag. (I do not know the slider blocks weight) By moving the pendulum mounts in 2 inches at 22.5 degrees allows me to add more weight without fear of damaging the plexiglass as when they were mounted out on the edge of the wheel. I will eventually get the complete wheel all back together in stages again to see what happens. It's just awful hot right now. Cheers

[ME]

When I first purchased these blocks they had roller bearings in them which were fairly tight to the shaft. I removed these ball bearings and installed the plastic races back in the slider blocks to keep clearance at a minimum. WRONG! These plastic races when cocked slightly were acting like a brake and were dragging on the shaft at times fooling me into thinking it was backdrag from the wheel. Well it was backdrag, but not because the pendulum weight couldn't push the slider.

Idea for avoiding that cart eating itself in the rails:
Perhaps you can use a single wheel that's sandwiched between two rails, not touching the upper one but with very small clearance.
The pendulum can be attached to that single axle.

I seen quickly that the timing was far too late. (Called Latency by ME which is correct! lol)

To accelerate an object (usually by gravity) up to speed or see it significantly change position is often called "Latency".
The term "Latency" suggests that it can be buffered in any orientation, I think such can cause confusion.
I never call it Latency :-)

Good luck. Try to move a bit slower in this heat. Stay safe.

[Calloway]

ME, One more comment I should make is any gravity design will have to pick up a weight(s) somewhere for it to work.There is no way around this. Imo. This design slides weight(s) up to adhere to this rule as I see it. Imo. What some may not realise or miss in this design is that once the slider weight starts to move or slide up is that this benifits or encourages and causes increased further wheel rotation with the pendulum weight pushing in tandem by moving up and to the right side. I have witnessed this by hand slowly turning the wheel to the right. Just get it started and keep going as it is a tandem move of sorts. That's the only way I know how to explain the process. Anyhow, just wanted to mention that if anybody's interested.

Cheers

[Wubbly]

Here's a video of the old Calloway wheel (not his latest concept): https://youtu.be/zQQAMrlJ-KQ

The motor velocity is slowly increased to show the path of the pendulums at different angular velocities.

There was some wind resistance added to stop the pendulums from wildly flailing about.

In all cases when the motor is turned off the wheel comes to a halt. This is only shown at the end of the video to make it shorter.

One of the masses is "tracked" so you can see the path of the masses at the different angular velocities of the wheel.

[Fletcher]

There was some wind resistance added to stop the pendulums from wildly flailing about.

fwiw .. if you also want to turn the slider transitioning bounce (impact wasted energy) into a dead cat bounce (dampened) you can change the elasticity setting for the grey rim blocks (1.00 full elasticity to 0.00 no elasticity .. in > Properties) to a very low value, if you haven't done so already. It just simulates more deformation losses of energy but you get your slider mass staying further on average to the side you need it, for longer.

It's like the difference between steel blocks and felt covered ones.

[Calloway]

When the pendulums go chaotic I believe it's because wheel speed out runs the pendulum weight fall. Imo. With the gravity speed of the falling pendulum weights at roughly 32 ft per second it wouldn't take much to do so. Imo. If a gravity wheel ever has success, I believe it's going to be rather slow. Again...imo.

Cheers

[Calloway]

Wubbly, Nice work. I watched it closely to detect backdrag and it does show it. Notice as the pendulum weight makes contact with the slider weight that the pendulum string does not remain vertical. Can you increase pendulum weight to decrease this? I don't know what your slider weight is either. Shouldn't matter actually if you can increase the pendulum weight. When I got my weight correct the pendulum weight string remains vertical while pushing the slider.

Cheers

[Tarsier79]

Could that just be hiding the problem?

[Fletcher]

Just my observations .. the faster the wheel is turned by the motor the greater is the Centripetal forces (inertial forces) on all bodies in proportion to their radius from the Center of Rotation. This 'holds out' the pendulums until gravity force reinstates itself and the pendulum begins to 'fall'. At one extreme, spin the wheel very fast and all the pendulums stay out all of the time. So there is probably an optimal speed (rpm) for best effect which will be quite slow as you have said.

The pattern (track) the pendulums draw as they go thru a cycle will settle down to one track followed by all, if the rpm is kept constant (that is after changing rpm - time to settle down).

IMO Calloway the pendulum string can never remain exactly vertical because of the sliders inertia. However, as you say, if the differential between your pendulum weights and sliders is very large then there will be little noticeable deviation from vertical, at constant rpm.

Wubbly has worked with the sim extensively (building and testing it) so he can probably give a clearer picture of whats happening. And the main sensitivities. And that should tally with your physical observations Calloway. If it doesn't then the sim can be tweaked, usually, until their performances reconcile. Part of that is to add air frictions.

[Calloway]

Hi Fletcher,

(IMO Calloway the pendulum string can never remain exactly vertical because of the sliders inertia. However, as you say, if the differential between your pendulum weights and sliders is very large then there will be little noticeable deviation from vertical, at constant rpm.)

I totally agree. It won't be exactly perfectly vertical, can't be. But get it as close as possible with pendulum weight. You can see the backdrag with the pendulum holding back the wheel rotation in the sim. I will have to video mine showing how the pendulum string remains vertical once I corrected the slider sticking problem and extra weight. This drops backdrag to a minimum. Imo.

[Calloway]

Hey Tarsier79, Just noticed your comment. Yes.

Cheers

[Wubbly]

... I don't know what your slider weight is either. ...

The input sliders in the upper lefthand side of the screen control the values. At the bottom of the input sliders there's a box that contains the current value of each.

... If a gravity wheel ever has success, I believe it's going to be rather slow. Again...imo.

Here's an animation of Bessler's four wheels. They ran rather quickly imo. https://youtu.be/l1PEs1Jcg1s

[John Collins]

I loved your animation of Bessler’s four wheels, wubbly! Do you mind if I link to it from my blog?

JC