rcmel,

As B.L.E. points out, you can expect flaperon deflection to change the "pitching moment" of the wing. Looking just at the WING, deflecting a flaperon down will almost always have a nose-down effect. BMatthews is correct in pointing out that the OVERALL effect of flaperon deflection "depends". Unlike your plane, some aircraft pitch up rather than down with flaperon deflection (this is often because the flap/flaperon reduces the tail's effective angle of attack). Such aircraft pitch up even though their wing experiences a nose-down pitching moment (you have to consider the whole aircraft).

If I read your initial post correctly, the thing that was making you scratch your head was: "by deflecting the flaperons down I've added lift, and that should make me go up, not down". If you held speed and angle of attack constant, deflecting a flaperon would normally increase lift, but in your case the nose-down moment discussed above reduces the angle of attack, and the net effect is a reduction in lift (a purist could point out that the CG initially makes a small upward excursion before starting down, but that's a very minor detail). As exeter_acres mentions, you can mix elevator in with flaperon deflection. You would probably want a combination that gave no change in lift as the flaperons are deflected (meaning your plane continues on the same flight path).

For a different reason I have found using flaperons to improve landing qualities a dicey proposition. When you apply "aileron" to a flaperon, you will obviously reach full downward deflection sooner if you have also applied "flaps". Once you reach full downward deflection your roll authority is essentially cut in half. Not only that, the "break" in roll response when you reach full deflection can lead to unpredictable roll behavior, and that can be more detrimental to your landings than a little extra speed. That said, it does make for interesting tinkering. Good luck, hope this helps.

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