with my 40size Cap 232 with 4 stroke SAITO FA65 engine... what would be a so called slow flyer sized prop for this motor?

APC 12.5X3.75

You might not like it though. This prop is best for fun fly planes with real thick wings. APC 13x4 might also work.

As suggested in post #2, a prop like that, or anything with a low pitch (the second number in the prop size) will slow things down. Just don't make it to slow or you will never get off the ground!! BUT you will have all sorts of power..


Four stroke engines tend to turn larger diameter props because they normally have a bit more torque, but lower horsepower. So, you can go larger in diameter than you can with two strokes, but four strokes don't turn the same RPM as a two stroke engine will. So, you can play a game trying to figure out what prop is right.

Suggestion.. buy one of several sizes, that size prop is fairly inexpensive, and try them out one at a time. You will most likely find the match up for your particular engine/airframe combination and end up with a few spares in your stock.

CGr.