Its very easy to ascertain which surfaces are experiencing flutter. All it takes is one small hole. As I have noted repeatedly 'After all else fails' AJ try the simple mass balance.

To arbitrarily dismiss mass balance as makeshift and even ignoring its usefulness as a diagnostic tool to identify which surfaces are affected as well as the only tool we normally have avalible to us is head in the sand thinking. Despite what some would have you think there are occasions when all the normal cures that is under discussion here do not work. This is the ideal candidate for mass balance.

There have been some more modern airplanes, typical scale aerobats or near scale that have had history of flutter. For some of these that I have assembled (arfs) for the fellows it was a very easy matter to insert a small ball of lead into the aerodynamic balance area of all the surfaces which thereby allows these portions of the surfaces that is forward of hingeline to also acts as internal mass balance in addition to aerodynamic balance area. In these cases none that I ever put together experienced flutter on any surface.

So AJ and agine your airplane is at risk for aileron flutter, so what are you gonna do?

John