Hey Rcpimpin,

The props you are describing are called "Prince Props" from Prince Aircraft. They can be found at:

http://tntlandinggear.com/

The curved tip is not for cooling of the engine. They are used to concentrate the prop wash on the flying surfaces. Otherwise, a lot of the prop wash is lost to the rudder, elevators, and the most pronounced portion of the ailerons close to the fuselage.

Ray