RE: a 13 pound plane with an os 91fx engine ?
You will have to fly it on the wing, something most RC pilots don't know how to do, If you get into a bad situation, you won't have enough motor to pull you out of it, so keep that in mind as you fly. Keep it smooth and don't do anything wild and you should be okay. None of this Bank yank stuff and keeo your takeoffs long and smooth with gentle climbouts. All I can say is AIRSPEED,AIRSPEED,AIRSPEED and prop it properly.