OTC
It's something I'd not really thought about until we got rain erosion on the prop on the aircraft I have a share in. When we took the prop off it was doweled to the boss and the boss was indexed by a master spline to the crank output shaft. So it would only fit in one position. Thinking a bit more about it, this could be more to do with the fact that its not fitted with a starter motor. This would fix the firing position of the impulse mag with the prop so that the blade is in the right position for swinging perhaps.
See what I mean about making you think
