I run a MAS(master airscrew) 10x6 with my LA .40 it pulls it nicely. I ran an APC 10x6 and tached out at 11300 RPM tuned for flight. the MAS pulls a little more RPM, I havent tached it yet but you can hear an increase. the plane is a bit faster and can climb out at a slightly steeper rate useing the MAS. a 10x5 prop should work fine.