[QUOTE=njhussey;30976
How does the motor work with a prop on it in a plane then? There is a circlip to stop the shaft pulling out if the motor is used as a pusher or reverse mounted but nothing to stop it being pulled out apart from the bearings and the grub screw as you say. This seems to be enough for a model so I'd have thought it would have been enough?[/QUOTE]

On a plane the magnitude axial force (thrust) from the motor is much smaller than in our application, plus accuracy (end-float, radial clearance etc) is pretty much irrelevant for just spinning a propeller. The bearings will wear out much faster than if they used angular contact beraings, but the cost isn't justified. If sufficient axial force is applied to a deep groove bearing the balls will ride up the sides of the rings outside of the superfinished races on to the rougher (relatively speaking) area of the ring, causing increased wear.

I'll reply to the rest when you've done a drawing...