Then you need to take a look at your flap servo geometry ! If you want maximum flutter resistance in the retracted position ensure that the geometry is such that the servo horn and the pushrod are in a straight line. That means that any flutter forces are trying to compress/ stretch the pushrod, moving the WHOLE sero on its mounts, which should be very solid, and the servo actually has very little work to do and has a large mechanical advantage to do what little IS neccessary ! Ideally of course in the full flap position the servo arm should have similar geometry but that would require a servo output travel of 180 degrees. This geometry also seriously considerably reduces servo current drain and, therefore, stress on the motor and associated electronics.

Of course the geometry in the intermediate flap setting is not important as speed is likely to be much lower and there fore the right servo will be able to hold it.

If thats not enough you need hydraulic screw jacks !

Regards,

David Gladwin.