Bob, as always- your son is the only one I know of who can't heat up the Ammo in the MX. I like the motor a lot- I have it's big brother doing about 600W sustained in a hotliner, and the airplane is absolutely ballistic -but in the MX, it's hard to keep in a decent temp range if you're doing more than hovering and circuits. The Ammo will push 180 degrees F in the same application that the Scorpions are running 120 to 130 degrees F. It's a good fixed wing motor, but it doesn't compare well in a helicopter.