Two things that seem to kill these tail motors on the AXE prematurely is not breaking in the brushes and heat. I got my idea from an air conditioner cooling fins. I used an aluminum can. First I wrapped the motor so I would have something to mount fins to (being sure not to cover the cooling ports and used heat transfer paste as well). Then put heat transfer paste in the middle and a drop of CA on both ends of the fins. It's not pretty, but it works.