Current set-up:





And here's the video

http://www.youtube.com/watch?v=rSLz4u3ybk4

You'll notice the first time I brake the clutch doesn't engage - this sometimes happens when the flywheel is going slower and doesn't have enough inertia to un-jam from the bottom of the threaded shaft. When going faster it usually separates fine, but I've only tested the thing up to 30% throttle (slightly worried bits will break if it's going too fast.. and as you can see it vibrates like mad). The motor has enough torque to re-screw the flywheel down the shaft after a release (it does this twice in the video). On the final release the cable pulled free from the clutch mountings (just a couple of M3 bolts):



It's not a big issue, I'll find a harder-wearing way of mounting it in future.

All in all I'm happy with the concept. Once it's in a fully-laden chassis (complete set-up weight is currently 700g, with lots of material to remove) it should hopefully move around a bit less although I don't doubt it will jump even higher with a weighted axe-head attached (and at higher flywheel speeds..). Still need to work out a re-cocking mechanism for the axe (possibly a spring).