Hi all aerodynamic gurus!
After many years of flying .40 - .90 sized aircraft my latest aircraft will be a little bit bigger and hence need more powerful servos, especially for the rudder. Since good quality hi-torque, hi-speed servos are quite expensive I am thinking about the possibility of using a boost tab on the rudder in order to lessen the strain on servo and linkage.

My question is about the size and effectiveness of boost tabs. What size should they be and how much should they deflect relative to the rudder. Is there a way to calculate (at least approximately) the influence of the boost tab on how much torque is needed to deflect the aileron by a certain angle at a certain speed?

Any help is very much appreciated.

/Red B.