You guys went from a very complicated description of flutter to a discussion of gap sealing. To set some of this straight. FLUTTER is caused on any surface by something being loose. It could be linkage, hinges, loose servo in it's mounts or broken gears. It is NOT cause by gaps between the moveable surface and the fixed surface. Gaps on fullscale aircraft of the aerobatic type and competition gliders are sealed for two reasons . One is to make the surface more efficient there by resulting in less required deflection and two causing less drag. If you experience flutter for any other reason it is an over speed condition caused by too much power resulting in speed for which the aircraft was not designed.