Abstract: An actuator system for a control surface of an aircraft having a hydraulic system and a source of actuation system commands. The actuator system includes hydraulic circuits connected to the aircraft hydraulic system and an electrically-powered hydraulic circuit integrated with the actuator. The electrically-powered hydraulic circuit includes an electric motor connected to a hydraulic fluid pump. The pump can be controlled to adapt to the power requirements to actuate the control surface.

Abstract: A relatively expensive, relatively heavy, and relatively nonflammable hydraulic fluid (chlorotrifluorethylene) is used in an aircraft ground wheel brake system between the piston (72) of a deboost device (68) and a set of wheel brakes (196). A relatively cheaper and relatively lighter, conventional hydraulic fluid (MIL-H-5606), which is also relatively flammable, is used in the remainder of the system. A replenish system for the relatively nonflammable fluid includes a reservoir divided into two chambers by a piston. One chamber contains a quantity of the relatively nonflammable fluid and the other chamber is connected to the system pressure. The deboost device includes a replenish valve which is opened in response to a position of the deboost piston. Replenishment only occurs when the brakes are applied and replenishment is necessary. At other times, all portions of the brake system are at return pressure.

Abstract: An electric stepping motor, operated by command pulses from a computer or microprocessor, rotates a rotary control member of a distributor valve, for sequencing hydraulic pressure and flow to the cylinders of one or more axial piston hydraulic motors. A group of the cylinders are subjected to pressure and flow and the remaining cylinders are vented to a return line. Rotation of the rotary control member sequences pressurization by progressively adding a cylinder to the forward edge to the pressurized group and removing a cylinder from the trailing edge of the pressurized group. The pistons of each new pressurized group function to rotate a wobble plate into a new position of equilibrium and the hold it in such position until another change in the makeup of the pressurized group. An increment of displacement of the rotary pressurized group. An increment of displacement of the rotary hydraulic motor occurs in direct response to each command pulse that is received by the stepping motor.

Abstract: An electric stepping motor, operated by command signals from a computer or a microprocessor, rotates a rotary control member of a distributor valve, for sequencing hydraulic pressure and hence flow to the cylinders of an axial piston hydraulic machine. A group of the cylinders are subjected to pressure and flow and the remaining cylinders are vented to a return line. Rotation of the rotary control valve member sequences pressurization by progressively adding a cylinder to the forward edge to the pressurized group and removing a cylinder from the trailing edge of the pressurized group. The double ended pistons of each new pressurized group function to drive a wobble plate into a new position of equilibrium and then hold it in such position until another change in the makeup of the pressurized group. These pistons also displace hydraulic fluid from the opposite cylinder head which serves as the output of a pumping element.