Don't bother with a speed controller for the axe, you'll need a switch or relay as you're looking for an instant acceleration. I used these in hornet and they happily handled a magmotor stalled for a few seconds so you should be fine.

http://www.jaycarelectronics.co.uk/prod ... BCATID=754

You won't find anything similar cheaper. Couple it along with a battleswitch etc and you'll have you're weapon control system that should happily handle your motor when stalled.