9 turns for jumping

Hobbyking 18A driving 9 turn stepper motor (1 min 37 sec)

Call it ignorance about magnetic theory, but for jumping movement, 9 turns ended up better than 50 turns. Where the 50 turn couldn't jump at all, the 9 turn jumped the 140g load quite efficiently with very little heating, at 20V. Surprised the maximum starting torque as well as the maximum speed increased, since one would think the 2 would trade places. Holding movement suffered, since it could no longer hold the load without instantly overheating.

The power supply showed 8A being used for jumping & 3A used for holding. The holding current couldn't be fine tuned below that. Software PWM isn't precise enough. There's a way to theoretically determine the optimum turns count, but prototyping has proven faster.

Decided to use active cooling to reduce the risk of a burnout. A scaled down version of the Minotaur's bounding movement is certainly possible. It would start as a single leg with 2 wheels, to predict performance. It wouldn't stand up when not jumping.