There is a difference...

The PTS prop is shaped purposely to slow the plane down and keep it within a certain airspeed range.

The blade pitch does not extend almost to the center of the blades as do the APC's and others.

I switched my 10 year old daughter's Alpha 40's PTS 3 blade prop out for an 11x5x3 and saw an immediate improvement in power and performance.

Since she is still learning I placed the PTS prop back on. She's more confortable with the more gentle handling.

Frankly that engine and plane is better off with an 11x6 2 blade prop... but that will come later.