I don't understand the reasoning for counterbalances. They reduce the force needed to move a control surface, but modern servos are plenty strong.

I do understand increasing the size of the rudder. But the what we want is the most force with the least drag so the plane doesn't slow too much in a maneuver, and a counterbalance surface sticking out in the breeze seems like it would be pretty draggy.

I've never tried a plane with and without. Is there any evidence that the counterbalances work better than just increasing the size of the surface?

Jim