BS,
I've got to say I'm with L'n'S. The difference in inertia is really marked on small motors like the A65 especially with 6ft props. My Cub prop will stop pretty much straight away in the air, but the same engine with a metal Mc McCauley as fitted in my old Taylorcraft would windmill all the way down. It's really noticeable when you swing them too - A good heave with the metal prop would spin the engine over two compressions!
Kingy