To those that don't know, it is probably a good idea to glue the standard motors into the heatsinks. One of mine pulled out at half revs. The little screw for the collar that tightens the heatsink around the motor, apparently is not up to the job, so I epoxied around the motor shaft then tightened the screw.
Also, thanks to a previous poster, I used the idea of drilling a hole through the foam nacelle to undo the screw that holds the heatsink to the motor stick. Then it's easy to pull out the motor.
Don't remount the motor back onto the stick until the glue is completely dry, otherwise some glue may get onto the stick & you will find it hard to remove the motor in the future
Epoxy didn't grip the steel well enough, so this what I finished up doing.
Use a 2mm hex head screw (so you can tighten it really tight).
In the pic it's a 3mm because that's all I had.