I made some things: Thermomagnetic Motors v1 "Hope" and V2 "Voldemort" and v3 "Wilson"

I made a thing!
It's a thermomagnetic motor, Version 1, based on this Tesla patent.
(Image Credit Tesla Universe)

It works, but not reliably.  I've played with it a lot, and think I've sorted out the figured out the key to the reliability issues.

Along the way, I build V2, a lovely exercise in minimalism that failed utterly.  I call it Voldemort, and won't mention it again.

This week I 3-d printed the parts for V3 "Wilson" at the Marietta Makerstation.

With a sufficient quantity of alcohol, this bears a resemblance to the character in the Castaway movie.

You might think "Hey, won't the 3-d printed plastic melt from the heat?"  You'd be exactly right.  This unit will probably melt during testing.  I hope to get some good data before it dies.

Here's what it should look like when finished.
 ... I wasn't sure how many cogs I'd need, but I think it's at least 4.  8 would be better.  I put holes in for 16.  Only one is shown here because it's a PITA to mate those in solidworks. 

The magnets came in the mail today.  Wish me luck!

Here's a brain teaser for you.  Thermomagnetic motors have historically had terribly efficiency.  This comes from a single common flaw.  Can you figure out what it is?  Email or comment if you think you've got it.  Elizabeth.a.greene@gmail.com