Member postings for Mike Everman

Preaching to the choir and just getting my thoughts straight, but an isochronous approach would only be useful on a free pendulum. Making it less concerned about amplitude allows you to impulse it less often. A traditional escapement would need to unlock and impulse perfectly centered for it to benefit from this, right?

Some random comments:

I tried the magnet/hoop thing and fringe effects dominated near the ends of the bar, as well as substantial eddy current damping, like imagine a Q of 2. Then, my simplistic EM drive was pulling on the steel of my bob, and through the data, I realized that the electromagnet was very slowly magnetizing the bob. Though the rate looked to be leveling off, it was in my tedious pre Microset days. I then just spent all my time on non-magnetic approaches, and have learned from recent experience that NdFeB magnets change quite radically with temperature.

This drives you to conceptually flip everything over and look at the rod as a support instead of a tension member, as it all must translate in the direction of swing.

If the bob is free to rotate, or more precisely, does not rotate with respect to ground, then every atom will follow the cycloid you've defined by whatever means. If it is rigid, all bets are off, and there is .

As I recall, what killed the cheeks on Huygen's pendulum was the energy lost rotating a rigid bob and rod below the silk threads. I believe Alan Emmerson wrote a definitive proof of how a compound pendulum could never use cycloidal cheeks for isochronism. My takeaway from that was, "Oh, I just need to make a massless rod and a point mass. Simple!"

Hi Gents, first post. Just wanted to chime in with my experience in this area. I've trod this path fairly deeply and made some rigs for testing. I wrote a paper on the subject for HSN 2009-5, which I would attach if I could.

Since writing that paper, I made another version of it that was higher fidelity, but still needs some things, of course. I do love the concept of a purely mechanical inverted pendulum, and it was very satisfying that it worked.

https://www.youtube.com/watch?v=RZyIPPZ6GXU

My takeaway from the whole project is that I think a rolling circular suspension has promise, if extremely polished and clean, but doubtful it will ever be a precision clock. The bob can fairly easily be made to follow a cycloid path, but the support itself must be made simply harmonic with a balance spring properly placed, which I have not added yet, as I have moved on.