2-blade vs 3-blade
 

Flying an OS-46 on a 3-blade 10X7.5. Will the plane fly faster on a 2-blade 10X7? The 2-bladed prop weighs 7 grams less, so perhaps I'll get more RPM, but I lose a little bit of the pitch. I can't go to a longer prop because of clearance. is there another prop you might recommend to pick up air speed?

Thanks.

How do you figure prop weight is going to affect rpm..?

The 10x7 2 blade is going to be less load than a 3 blade 10x7.5, so I expect it to turn more rpm and is likely to bring the engine up the horsepower curve a bit but depends on which model .46. I would expect a bit more speed on a clean airframe - the 10-7 APC - .46 combo is known to pull Quickie 500's along pretty smartly. If you want a similar load then 10-8 is closer but I doubt faster.

Thanks. I will try the 10X7 and compare.

3-blade prop has more tip loss and requires more power to turn it at = RPM

If you choose a 3 blade prop that takes good advantage of your engine's power and gives the airframe adequate thrust, they work just fine. I rarely have a reason to use one, other than curiosity.