Solenoid-operated control valves

THE presentation of a paper on electric aircraft apparatus by manufacturers of hydraulic control equipment is very likely to lead to a discussion^1,5 of the relative advantages and disadvantages of hydraulic and electric systems for accessory actuation. Let us evade this controversy for the present by stating that the writers are not advocating either an all-electric or all-hydraulic system but are describing a type of device that makes possible the utilization of some of the best features of both forms of power.