Something else to consider is the amount of travel required. A pattern aircraft doesn’t need the extreme throws that a 3D aircraft would. A long servo arm is usually needed in order to achieve these large control surface movements. Torque is force applied on a lever arm; so, if you change the lever arm, you change the needed torque. Correct me if I’m wrong, but I believe a 100-oz/in servo can deliver a force of 100 oz at a moment arm of 1 in. If that arm is increased to two inches, the servo will only provide 50 oz of force but at a greater range of travel.

-Clint