As the spec's for the HobbyKing motor say, it is 5mm. I measured it. The oringinal chinese motor is an outrunner and the shaft only sticks out about 1 inch and uses a collet-type prop adapter. I'm using a 10x5 prop The new KMS motor i have, has a 4mm shaft. I measured it. And is also an outrunner and the shaft on the new motor about an inch long also. The ESC (little flat thingy) has no markings on it what so ever, however the spec's above for the original chinese motor show a max 40 amps so i believe it should be something at least 40amp if not a little higher. The fledgling is not really a small plane but it is not a big one either. 50"ish wingspan.

The prop adapter that comes with the new KMS motor bolts to the back of the motor and has a nut to hold onto the prop. Unlike the collet style the old chinese motor has.

I would like to buy a motor locally that will fit correctly without alot of trouble, but also not costing an arm and a leg. The people at the LHS really don't know jack about the electric motors to be able to point me to the right one.

skeeter