Sorry. Woj, you've missed the point. If, in the flaps RETRACTED position, the rod and servo arm are arranged so that they are in exactly a straight line then the load on the servo is very small and the flap is held in EXACTLY the right position at very little servo load, digital servos could have been designed for exactly this application. I guaranteee that this setup gives an absolutely solid flap position and any up/down movement of the flap, as in the case of flutter, is resisted mechanically, not electronically, as the the flap movement does not translate into an angular movement of the servo arm, it just tries to rock the entire servo, which is screwed down hard thus resisting the flutter !

Regards, David Gladwin.