The aircraft was designed to be inherently stable in both roll and pitch. There's probably positive incidence in the wing (most likely a flat-bottom or semi-sym airfoil) and down thrust in the engine that make it pitch stable. All that works against you when you want to fly inverted. There's not much you can really do to improve this without making some fairly drastic trim changes that will likely make it somewhat squirrely.
Sounds like you're ready to move up to an intermediate or better plane capable of more aerobatics that your trainer.
ORIGINAL: glowfuel
Was given an older trainer. Believe it was built in the late 70's. Still in great shape and hardly used. Having a problem flying inverted. Need a ton of down elevator, when inverted, to barely keep the nose up. Elevator throws are about 1.2" in each direction. Am running an OS 40 LA engine and the plane has way enough power. The wingspan is about 48 inches. Normal, level flight needs about 1/4", up trim, deflection to keep the model flying upright, straight and level. The CG is balanced on the main wing spar. Would it help to bring the CG aft or is the plane so inherently stable, with its design, that inverted flight in not likely? Maybe a different elevator design? the pic is provided below. Any input will be appreciated.
Thanks.........
