ORIGINAL: Harley Condra
ORIGINAL: redtail
Sorry to keep troubling all of you, but I really need your advice. What size (1'', 1.25'', etc.) SWB servo arm should I buy for the elevators, ailerons, and flaps. Many thanks. Chic
One thing to remember is the way servo torque is measured. The advertised torque is measured 1.00'' from of the center of rotation. The longer the arm, the lower the available torque. Short servo arms produce more torque.
Keep them as short as practical.
The instruction manual or plans of a well engineered model will call out the servo type, the arm length the surface deflection on all control surfaces. Also, the neutral position of the servo arms will be shown, in order to establish the proper aileron differential.
Actually, torque is independent of the distance from the centre. Force is what varies. Torque is measured in force/distance. So, the longer the distance, the lower the force and viceversa
So, if a manufacturer advertises 300 oz/in, it means that at 1.00 from the center, the force is 300 oz. At 2" it will be 150 oz of force, and at .5" it will be 600 Oz of force. But the torque is the same at every distance