I have use the 148 servos in many big planes, one a Phaeton90 with a Quadra 72CC engine for literally hundreds of flight with pull-pull on both rudder and elevator with absolutely no problems. Just do not put excessive tension on the lines, just enough to eliminate any droop or slack at neutral. A high tension will ruin any servo after a time. I have found that the Futaba 148's to be one of the most reliable and relative inexpensive servos ever made.