I´m running an O.S. 61 FX w/apc 12X6 elevator servo in the fuselage and rudder servo in the tail, I do all my aerobatics at 55% 65% throttle but for hover you need more than 90% power, overall the plane flies great. knife edge need a little up elevator you can mixed but is not necesary because de amount of up elevator is minimum with practice you can get beatiful knife edges