Ray Allen servos were designed specifically to control trim surfaces in homebuilt aircraft. They can also be used to operate other mechanisms within your aircraft, thus eliminating the need for bulky cables and pulleys.
Ray Allen servos operate on 12-14 volts DC. When activated they push or pull with tremendous force. Since this thrust is generated by means of a jackshaft (T2 series) or a jackscrew (T3 series), the output shaft will lock in any position when the electrical power is off. They will automatically stop when their travel limit is reached. No electronics are used to control Ray Allen servos and they will not travel unless power is switched on by the pilot. Voltage polarity determines the direction of travel.
Ray Allen has three different T2 and T3 servos available:
T2-7A servo has .7" (17mm) travel
T2-10A servo has 1.0" (26mm) travel
T3-12A servo has 1.2" (31 mm) travel
The miniature T4-5 is designed for installation in very small ailerons and rudders. It is not recommended for elevator trim. The internal working mechanism is, in principle, the same as that used in the T3 series servo.