Gravity Wheel

[dradford]

Wubbly, thank you so much for creating that simulation, that must have taken a long time to do, very impressive.
I looked at WM2D and it was way out of my price range - is there anything else that will run your simulation, that is (a lot) cheaper, or free?
I would post up my Algodoo file of a wheel with eight pendulums on it, but the forum wouldn't let me do it. The motion of the pendulums in Algodoo is completely unrealistic, they swing far too wildly, so I don't think Algodoo can be trusted as a simulator.

[agor95]

That's because you're pulling on the wheel, as in the example with the 10" string.

So the pendulum needs to be pulled up against gravity to cause this effect.

That is reasonable.

I think we need a 'Calloway Trebuchet GW' model.

That is one pendulum, one slider pair and a counter weight for the pendulum.

The slider pair and rotational inertia give the pull required.

Cheers

[agor95]

WM2D and it was way out of my price range

Well I am doing it the hard free solution way, but it takes alot of time and learning.

When calculating the path of a dynamic system in incremental steps. These are made of straight movements that approximate a curve of inertial forces.

You get into a world were a more realistic model requires more smaller incremental steps. That results in a slower run.

So you have to split the computation from the presentation.

Or go for the really hard way.

Regards

[eccentrically1]

That's because you're pulling on the wheel, as in the example with the 10" string.

So the pendulum needs to be pulled up against gravity to cause this effect.

That is reasonable.

I think we need a 'Calloway Trebuchet GW' model.

That is one pendulum, one slider pair and a counter weight for the pendulum.

The slider pair and rotational inertia give the pull required.

Cheers

No, it would be two pendulums and one pair of sliding weights. One pendulum wouldn't be balanced by a stationary counterweight.

And, don't fall into the inertia trap. Inertia doesn't multiply. It only gives back what it's given. Conservative law, so the sliding pair won't give the pull required.

[agor95]

don't fall into the inertia trap

I am taking your advice - there are so many traps out in this kinetic world.

Cheers

[Wubbly]

@dradford, The sim only works in WM2D. You might want to look into a 'student version' of the software, or a 'trial' version as described on their website.

Some people say WM2D is easy to use. I found it horrendously difficult to learn and use. I think it fried my brain and made my eyes glow.

[Calloway]

Wubbly,

<I think it fried my brain and made my eyes glow.>


Lmao....Thank you also for taking the time to make the sim as others also. It does give us all another method of looking at these designs. Cheers

[silent]

So now the question is, has anyone been able to make this work yet?

silent

[agor95]

So now the question is, has anyone been able to make this work yet?

I recommend a test setup in WMD. It will take me some time to create it from scratch.

A wheel rotating at a fixed rate.
A rod with a mass at the end. Like the pendulums used in a Calloway.

Slider weights which receive contact by the pendulum.

The idea is to explore the pendulum behavior.

The behavior we should be looking for is the pendulum lagging. Also the interaction of the pendulum moving the slider weights.

The main focus is getting the pendulum to have a stable behavior on several rotations of the wheel.

There are many variables like the distance axle to bolt, pendulum length, pendulum mass, contact point with sliders and slider mass etc.

P.S. Has Sir baught a wip :-) We only have W.I.P.s at this time.

All The Best

[Calloway]

Hello Silent, I changed my blocks on the slider shafts to pvc and that didn't turn out well either. The problem with my blocks was they kept rolling on the shafts. The pendulums hitting the gloves was unpredictable. My end shaft supports are too tall. Now I have ordered pillow block bearings to fit the 8mm shafts. They don't turn but just support the shafts. The center line of the shafts to the disk will be very close now so the blocks won't roll but still allow some clearance from the disk. I should be able to get a more precise adjustment to the gloves. Waiting on my order to ship from Amazon. Maybe next week I will know more. Cheers

[Fletcher]

@dradford, The sim only works in WM2D. You might want to look into a 'student version' of the software, or a 'trial' version as described on their website.

Some people say WM2D is easy to use. I found it horrendously difficult to learn and use. I think it fried my brain and made my eyes glow.

Hey Wubbly .. in case you haven't got these. Coulda saved your eyes.

P.S. there is an awesome automated string length pulley and block build in the section on scripting examples IIRC.

I remember some people were grabbing cracked older versions from the net years ago. Took a bit of digging IINM.

[Wubbly]

Thankyou Fletcher. I've seen those. They came with the program and are in the "manuals" folder in my version of the software.

Started working through the examples in the 204 page Tutorial guide. Finished the piston engine chapter before I got bored.

The formula reference is an appendix in the 429 page user guide that came with the program and I occasionally have to look at that.

Probably spent the most time looking at the 794 page WMBasic language guide that came with the program until I realized the appendix I kept using was identical to the help file in the script editor, and it was easier to navigate the help rather than to navigate the PDF.

[eccentrically1]

don't fall into the inertia trap

I am taking your advice - there are so many traps out in this kinetic world.

Cheers

Yes, there are. I = mr(2) is an easy one to fall into.

I was looking at the math for compound pendulums. It's wild.

[agor95]

Hi eccentrically1

Math on compound pendulums is wild.

I am looking into a jungle of maths and wondering if I can get out alive.
Is there members who can help? Do I dare dive in and start hacking at these formula.

The hope is to create formulas that give us the angles for each pendulums and axle after a period of time from their initial state.

Therefore we would not have to iterate to get the same result.

That should generate less calculation errors.

I have been trying to get the skill for some months.

P.S. You can see rope/strings are well impossible to compute.

Cheers

[fredos]

Hi ,

First of all, I want to congrats Calloway for his very interesting design of his wheel.

Agor, I agree with you.The jungle of math for the Calloway Wheel is very huge.it took me nearly 2 weeks to write the document below and the Matlab script. For those who don't know what is matlab, google it.

I have put in equations the wheel and all the interactions between the pendulums and sliding weights.

Of course, I am not an expert in mathematics and ,for sure, there are mistakes in the document file.
So, this document must be taken as a draft and must be verified by a third party.

I have used matlab for performing simulation of the behavior of the wheel but i can not say if the wheel turns or not ( because i am not sure of my equations and it requires a lot of time to verify again and again and again ....).
The script permits to draw the graphics of the gravity centers of the sliding weights and pendulum weights versus the wheel angle (called theta in the document).

I post also my Matlab script but also, this script has to be verified by a third party to confirm or not the behavior of the Calloway wheel.

Also, as English is not my mother language, the speeling can be strange

cheers