Abstract: A flow restrictor includes a first flowbody defining a first end portion, a second end portion opposite the first end portion and an orifice between the first end portion and the second end portion. The first end portion defines a plurality of first slots, and the second end portion defines a counterbore having a first diameter. The flow restrictor includes a second flowbody defining a plurality of second slots and having a second diameter proximate the plurality of second slots that is greater than the first diameter of the first flowbody. The second flowbody is configured to be received within the counterbore of the first flowbody.

Abstract: An actuator includes a housing that defines a first inlet to receive a fluid, a second inlet to receive the fluid and a chamber. The actuator includes an actuator rod movably coupled to the housing. The actuator rod includes a head. A first face of the head is responsive to the fluid from the first inlet, and a second face of the head is responsive to the fluid from the second inlet to move the actuator rod. The head defines at least one cross-bore. The actuator includes at least one plug coupled to the cross-bore to inhibit a flow of the fluid through the cross-bore in a first state such that the plug fluidly isolates the fluid from the first inlet from the fluid from the second inlet. The plug is to enable the flow of the fluid through the at least one plug in a second state.

Abstract: A metering valve includes a valve body, a valve element, a rotary servo, and a stepper motor. The valve body has a valve chamber, a fluid inlet port, a fluid outlet port, a metering valve control pressure inlet port, a servo control pressure inlet port, and a servo control pressure outlet port. The valve element is movably disposed within the valve chamber and defines therein at least a control pressure chamber and a return pressure chamber. The valve element is responsive to fluid pressure in the control pressure chamber to move between a closed position and a plurality of open positions. The rotary servo is rotatable about a rotational axis to a plurality of servo positions to thereby vary fluid pressure in the control pressure chamber. The stepper motor is responsive to commands to rotate the rotary servo to a commanded servo position.

Abstract: An actuator includes a housing that defines a first inlet to receive a fluid, a second inlet to receive the fluid and a chamber. The actuator includes an actuator rod movably coupled to the housing. The actuator rod includes a head. A first face of the head is responsive to the fluid from the first inlet, and a second face of the head is responsive to the fluid from the second inlet to move the actuator rod. The head defines at least one cross-bore. The actuator includes at least one plug coupled to the cross-bore to inhibit a flow of the fluid through the cross-bore in a first state such that the plug fluidly isolates the fluid from the first inlet from the fluid from the second inlet. The plug is to enable the flow of the fluid through the at least one plug in a second state.

Abstract: A propeller oil control system for a turboprop engine of an aircraft includes an engine control unit and a propeller oil controller. The engine control unit is operable to determine a flight phase of the aircraft and is configured to supply control commands. The propeller oil controller is coupled to receive a supply of oil and to discharge the oil at a discharge oil pressure. The propeller oil controller includes an electrohydraulic servo valve that receives the control commands moves to a plurality of positions between a first position and a mid-position, and a plurality of positions between the mid-position and a second position. The engine control unit only commands the electrohydraulic servo valve to move out of the first position when the engine control unit determines the aircraft is conducting a take-off roll or the aircraft is in flight.

Abstract: A propeller pitch control system for a turboprop engine of an aircraft includes an engine control unit and a pitch control unit. The engine control unit is operable to determine a phase of flight of the aircraft and is configured to supply control commands. The pitch control unit is coupled to receive the control commands from the engine control unit and includes a housing, a beta piston, a position sensor, a beta tube, and an electrohydraulic valve. The engine control unit only commands the electrohydraulic valve to move the beta piston from the fully retracted position when the engine control unit determines the aircraft is conducting pre-takeoff roll taxiing operations or is conducting post landing touchdown operations.

Abstract: Additively-manufactured flow restrictors are provided, as are methods for producing additively-manufactured flow restrictors. In various embodiments, the additively-manufactured flow restrictor includes a flowbody through which a flow path extends, a restricted orifice located in the flowbody and providing a predetermined resistance to fluid flowing along the flow path in a first flow direction, and a first internal perforated screen positioned in the flow path upstream of the restricted orifice taken in the first flow direction. The flowbody and the first internal perforated screen integrally formed as a single additively-manufactured piece utilizing, for example, Direct Metal Laser Sintering (DMLS) or another additive manufacturing process. In certain embodiments, the first internal perforated screen may include an endwall and a peripheral sidewall, which is integrally formed with the endwall and spaced from an inner circumferential surface of the flowbody by an annular clearance.

Abstract: A propeller oil control system for a turboprop engine of an aircraft includes an engine control unit and a propeller oil controller. The engine control unit is operable to determine a flight phase of the aircraft and is configured to supply control commands. The propeller oil controller is coupled to receive a supply of oil and to discharge the oil at a discharge oil pressure. The propeller oil controller includes an electrohydraulic servo valve that receives the control commands moves to a plurality of positions between a first position and a mid-position, and a plurality of positions between the mid-position and a second position. The engine control unit only commands the electrohydraulic servo valve to move out of the first position when the engine control unit determines the aircraft is conducting a take-off roll or the aircraft is in flight.

Abstract: A propeller pitch control system for a turboprop engine of an aircraft includes an engine control unit and a pitch control unit. The engine control unit is operable to determine a phase of flight of the aircraft and is configured to supply control commands. The pitch control unit is coupled to receive the control commands from the engine control unit and includes a housing, a beta piston, a position sensor, a beta tube, and an electrohydraulic valve. The engine control unit only commands the electrohydraulic valve to move the beta piston from the fully retracted position when the engine control unit determines the aircraft is conducting pre-takeoff roll taxiing operations or is conducting post landing touchdown operations.

Abstract: Additively-manufactured flow restrictors are provided, as are methods for producing additively-manufactured flow restrictors. In various embodiments, the additively-manufactured flow restrictor includes a flowbody through which a flow path extends, a restricted orifice located in the flowbody and providing a predetermined resistance to fluid flowing along the flow path in a first flow direction, and a first internal perforated screen positioned in the flow path upstream of the restricted orifice taken in the first flow direction. The flowbody and the first internal perforated screen integrally formed as a single additively-manufactured piece utilizing, for example, Direct Metal Laser Sintering (DMLS) or another additive manufacturing process. In certain embodiments, the first internal perforated screen may include an endwall and a peripheral sidewall, which is integrally formed with the endwall and spaced from an inner circumferential surface of the flowbody by an annular clearance.

Abstract: A torque motor valve actuator for use with a valve assembly is provided. The torque motor valve actuator includes an armature spring having a first end portion, a second end portion and a rigid central portion. The first end portion and the second end portion are coupled to the rigid central portion by a respective flexible portion, and the rigid central portion defines a bore that extends along a first axis. The torque motor valve actuator includes an armature having a first end and a second end. The armature extends along a longitudinal axis that is substantially parallel to the first axis of the bore, and the armature is coupled to the bore of the armature spring between the first end and the second end.

Abstract: A torque motor valve actuator for use with a valve assembly is provided. The torque motor valve actuator includes an armature spring having a first end portion, a second end portion and a rigid central portion. The first end portion and the second end portion are coupled to the rigid central portion by a respective flexible portion, and the rigid central portion defines a bore that extends along a first axis. The torque motor valve actuator includes an armature having a first end and a second end. The armature extends along a longitudinal axis that is substantially parallel to the first axis of the bore, and the armature is coupled to the bore of the armature spring between the first end and the second end.

Abstract: Flapper assemblies for torque motors of electrohydraulic valves are provided. The flapper assembly comprises a flapper having an upper end portion configured for coupling to an armature and armature-flapper support of the torque motor and a lower end portion having a socket therein. A hemispherical closure member having a flat diametrical face configured to seal against a nozzle outlet is disposed for oscillatory movement in the socket. A retaining clip is slidably mounted about the lower end portion and has a retention opening exposing the flat diametrical face and sized to retain the hemispherical closure member in the socket. The torque motor comprises the armature coupled to the armature-flapper support, the flapper assembly, and a plurality of coils. The electrohydraulic valve comprises the torque motor and a nozzle configured to be in fluid communication with the flapper assembly when the electrohydraulic valve is in an open position.

Abstract: A torque motor valve actuator includes a first magnetic pole piece, a second magnetic pole piece, an armature, and a coil. The first magnetic pole piece is of a first magnetic polarity. The second magnetic pole piece is of a second magnetic polarity, and is spaced apart from the first magnetic pole piece to define a gap. The armature is rotationally mounted and disposed in the gap between the first and second magnetic pole pieces. The coil surrounds at least a portion of the armature and is disposed such that it is not surrounded by either the first magnetic pole piece or the second magnetic pole piece. The coil is adapted to receive electric current and is configured, upon receipt thereof, to generate a magnetic force that causes the armature to rotate.

Abstract: Flapper assemblies for torque motors of electrohydraulic valves are provided. The flapper assembly comprises a flapper having an upper end portion configured for coupling to an armature and armature-flapper support of the torque motor and a lower end portion having a socket therein. A hemispherical closure member having a flat diametrical face configured to seal against a nozzle outlet is disposed for oscillatory movement in the socket. A retaining clip is slidably mounted about the lower end portion and has a retention opening exposing the flat diametrical face and sized to retain the hemispherical closure member in the socket. The torque motor comprises the armature coupled to the armature-flapper support, the flapper assembly, and a plurality of coils. The electrohydraulic valve comprises the torque motor and a nozzle configured to be in fluid communication with the flapper assembly when the electrohydraulic valve is in an open position.

Abstract: A torque motor valve actuator includes a first magnetic pole piece, a second magnetic pole piece, an armature, and a coil. The first magnetic pole piece is of a first magnetic polarity. The second magnetic pole piece is of a second magnetic polarity, and is spaced apart from the first magnetic pole piece to define a gap. The armature is rotationally mounted and disposed in the gap between the first and second magnetic pole pieces. The coil surrounds at least a portion of the armature and is disposed such that it is not surrounded by either the first magnetic pole piece or the second magnetic pole piece. The coil is adapted to receive electric current and is configured, upon receipt thereof, to generate a magnetic force that causes the armature to rotate.