I have a DL-50 on a Comp-ARF Extra 2X2m that weighs in at 13.5 lbs. I had to get a little creative with my throttle setup as the Spektrum DX7 does not have throttle curve capability in Airplane mode. The Extra was a little tough to hover since the engine makes about 30 lbs of thrust and so accordingly very little throttle change makes for somewhat big changes in thrust output. I did wind up doubling the length of the arm on the carb for better resolution and also setting the servo arm up so as to get very little movement of the carb for the initial portion of the travel. Works pretty good now.