Just as a point of intrest the more blades a prop has the less efficient it becomes. From what I understand about it it's because the next blade arrives before "clean" air has arrived. I don't know if you are familiar with control line flying , but there was a time when the speed planes all used props with only one blade! The primary reason for multi blade props is that in real aircraft a high horsepower two blade prop would have to be so large,it would not allow enough ground clearance. They do however look cool, and I think they may be a little less noisey because at the same RPM a larger two blade would have a higher tip speed than the smaller three blade.