An Electrically Operated Hydraulic Control Valve

Early in the study of the N I K E guided missile project, it became apparent that the requirements for the fin actuators could not be fulfilled by the servo-mechanisms available at that time (1945). All existing types failed to meet the combined requirements of small size, light weight, high torque, and rapid response. Further investigation showed that the development of a hydraulic servo employing an electrohydraulic transducer appeared to provide a promising solution. A control system of this type, therefore, has been developed for the N I K E missile. The design of the transducer, or control valve, was one of the principal problems in the development of the missile control systems and is the subject of this article. The specific design of the valve that will be discussed here is known as "Model J-7", and represents the state of the development in 1950. Valves of this type, with varying degrees of modification, arc used in missiles of several other projects. APPLICATION Fig. 1 is a simplified schematic of the roll positioning system in the N I K E missile. It is the simplest of the three applications of the valve in the missile, but will serve to illustrate the situation in which the valve operates. The purpose of the roll servo is to keep the missile in a predictable roll orientation. 711