Four Star 60 ailerons thickness
"Pat, the aileron is supposed to be thicker. Do not sand it. Aerodynamically, it is supposed to expand the "flight envelope" i.e. the minimum controllable airspeed is lowered, and also to reduce flutter. I still seal all my hinge gaps with clear monokote to prevent flutter."
rajul is correct.
It does expand the "flight envelope".
Don't sand it.