just finihed a 4* arf would like to no if a OS 52S is a good engine ti install and what size prop would be best thank you

Having had this exact combo, I recommend an 11x7. The 52FS is a great motor for this plane and will pull it around with plenty of power. It also helps slow it down at low idle for easy 3 point landings. Your gonna love this plane![8D]

I tried a 12x8 on a Saito 56 before, I think you might be able to get away with a 12x6 on the OS52, it will give you more thrust. Try and see if it can tach at about a minimum of 9,200 RPM.