--------- PS: Rudeboy, why should the aileron NOT be fully balanced, only partly..?


If the mass distruibution is such that the center of mass of the aileron is in front of the hinge line it is basically an unstable system. Mass on the hinge line is neutral and mass aft of the hinge line is a stable system.

So you want it a little aft of the hinge line to be stable and ease the mass inertia loads on the servo. Then you are left with the airloads.

!!!!!!! Note, the above is not true unless it is standing on its tail!! I goofed with this statement. It is the total moment of inertia of the surface that effects the frequency that the surface will flutter at. !!!!!!!!!!!!!!

Airload balancing is done the same way. There is a bias because the loads are at the 25% point of the surface (kinda) and make a forward airload tab more effective. You want enough to unload the servo but still want the resultant of the airloads aft of the hinge line to have a stable system.

If you use a set of springs to neutralize the aileron the problem is that it will help make it buzz at some frequencies. If you use a spring of some sort you also need a damper of some sort to stop the spring natural frequency thing from being more of a problem than a solution.

There are all sorts of good equations that will let you determine what happens where but I darn near flunked dynamics and have conviently forgotten what they are.