Here's an interesting question along the same "propeller" line of questions that I just thought of:

When you change from a wood prop like an 11x8 Thrustmaster to a nylon glass-filled prop (on a .60 engine), should you change the size or pitch of the propeller to get the same flight characteristics? I know that an 11x8 wooden prop is going to weigh more than an 11x8 nylon and since the efficiency of the engine rpm/prop combination is affected by the weight/size of the prop it's swinging, wouldn't a heavier wooden prop have different effects on the engine characteristics than a nylon prop? And should it be substituted with a "sport" nylon prop or some other style of prop? What would be a comparable prop size/style?

This can be a convoluted problem with alot of different engine efficiency factors and aerodynamic issues to address.....

Incidentally, props are alot cheaper than I would have thought they'd be! (most nylons are under $3-$4 each! I can afford to keep a dozen around for the "just in case" situations )