I happen to have a bunch of aircraft engines, so I borrowed the thrust washer from one of those to put the prop on... You do need that, or something which will work as a replacement in order to mount a prop.

SOME clutches are made in such a way that you can use a portion of the clutch as the thrust washer. (most are not able to be set up n this way. [img]i/expressions/face-icon-small-sad.gif[/img] )

Breaking in with a prop is easier than trying to do it with the engine in the heli, but it is possible to break it in while mounted in the heli. Set the main rotor pitch curve to constant -1 deg, and the thing can't take off accidentally. [img]i/expressions/face-icon-small-wink.gif[/img]