ORIGINAL: ytell
If the plane pulls to the belly on vertical line, so they say, increase your wing incidence.
How can this be true if the elevator trim position is not changed? as fa as I understand, the elevator will keep the wing in the same AOA regardless of wing incidence change (assuming constant speed is maintained)
Yoav
I'm pretty sure it's not possible to trim most models to be neutral in all aspects. It would have to be a near symmetrical (wing AND body shape) pattern type with retracts. Most flight trim techniques are for short duration tendencies, not prolonged flight in a given aspect. If it flies straight for two or three seconds hands off that's enough to tell.
In your example you are changing the wing attack, but not the horizintal stab incedence OR the engine offsets. Typically an engine is offset down a few degrees and right a few degrees to the datum line to counter the tendency to climb with added thrust and counter engine/prop torque. Even that ideal angle is dependant on throttle/thrust and will change in flight,; so you design for an envelope.