RE: Question about flaps and flaperons
Every aircraft I have ever flown (that has flaps), when the flaps are deployed, the nose goes down.
As far as designing a model that will not do this, it is not likely.
You are changing the airfoil and the angle of attack of the wing, therefore the trim is going to change.
You cannot change the wing configuration without changing the tail configuration.
Even with 0/0 incidence, you will have the same trim problem. It is unavoidable.
On the Decathaolon, when you trim it to fly straight, is the elevator in line with the horizontal stab?
Doug