motorbearing

The propeller can be classified in different ways. What we are really interested in is the diameter and pitch of the propeller. It will be discussed in the next section:
Blade count
Single paddle: racing machine is commonly used, can avoid eating the front lobe of the tail flow, the best efficiency, but the other end to trim.
Two: the most common type, reasonable efficiency, easy to balance.
More than three propeller blade length: like the real machine or limited use, less efficiency.
Thrust direction
Tension paddle: positive propeller, pulling force from the front of the aircraft to make the plane forward.
Thrust impeller: that is, the propeller pushes the aircraft forward from the rear of the aircraft, and a few engines can be reversed. One of the engines reverses the anti torque by using the paddle to reverse the propeller.
Material value
Wood paddle: good rigidity, light weight, but easy to damage.
Plastic paddles: cheap, selective, less damaging.
Carbon fiber paddle: the best and most expensive.