A propeller pitch control system for a turboprop engine of an aircraft includes a negative torque sensor, a full feather control valve assembly, and a feather valve assembly. The feather valve assembly is responsive to fluid pressures from the negative torque sensor and the control valve assembly to move between a plurality of positions. An engine control unit or a manual user interface can also be used to control the position of the feather.

A propeller pitch control system for a turboprop engine of an aircraft includes a negative torque sensor, a full feather control valve assembly, and a feather valve assembly. The feather valve assembly is responsive to fluid pressures from the negative torque sensor and the control valve assembly to move between a plurality of positions. An engine control unit or a manual user interface can also be used to control the position of the feather.

A control circuit for changing the angle of propeller blades includes a propeller pitch change mechanism, and a fixed-displacement pump providing the supply of oil from an engine oil return system. A valve has an outlet port to direct oil from a cavity of the valve, and a pitch port in fluid communication with the pitch change mechanism. A spool of the valve is operable between a first position and a second position to respectively open and close the outlet port, and direct oil flow away from or to the pitch change mechanism.

A control circuit for changing the angle of propeller blades includes a propeller pitch change mechanism, and a fixed-displacement pump providing the supply of oil from an engine oil return system. A valve has an outlet port to direct oil from a cavity of the valve, and a pitch port in fluid communication with the pitch change mechanism. A spool of the valve is operable between a first position and a second position to respectively open and close the outlet port, and direct oil flow away from or to the pitch change mechanism.

Systems and methods are disclosed for controlling the pitch angle of a propeller and rotor assembly that selectively limit the pitch angle according to a selected mode of operation. The system includes an actuator having forward and aft chambers, an oil transfer bearing (OTB), and a fine stop collar. The fine stop collar including a first passage in fluid communication with the OTB and forward chamber during a ground-based mode of operation, and a second fluid passage being in fluid communication with the OTB and forward chamber during a flight-based mode of operation.

Systems and methods are disclosed for controlling the pitch angle of a propeller and rotor assembly that selectively limit the pitch angle according to a selected mode of operation. The system includes an actuator having forward and aft chambers, an oil transfer bearing (OTB), and a fine stop collar. The fine stop collar including a first passage in fluid communication with the OTB and forward chamber during a ground-based mode of operation, and a second fluid passage being in fluid communication with the OTB and forward chamber during a flight-based mode of operation.

Methods and systems for governing an aircraft propeller of an engine are described. The method comprises obtaining a fluid flow command for speed control of the propeller, determining pulse parameters of a pulse width modulated valve control signal for actuating a two-position solenoid valve in accordance with the fluid flow command based on an average fluid flow through the solenoid valve and an opening and closing time of the solenoid valve, generating the valve control signal with the pulse parameters as determined, and transmitting the valve control signal to the solenoid valve for actuating the solenoid valve, thereby controlling the speed of the propeller.

A propeller pitch control system for a turboprop engine of an aircraft includes a negative torque sensor, a full feather control valve assembly, and a feather valve assembly. The feather valve assembly is responsive to fluid pressures from the negative torque sensor and the control valve assembly to move between a plurality of positions. An engine control unit or a manual user interface can also be used to control the position of the feather.

A propeller pitch control system for a turboprop engine of an aircraft includes a negative torque sensor, a full feather control valve assembly, and a feather valve assembly. The feather valve assembly is responsive to fluid pressures from the negative torque sensor and the control valve assembly to move between a plurality of positions. An engine control unit or a manual user interface can also be used to control the position of the feather.

The present disclosure is directed to a turbine engine (10) defining an axial direction, a radial direction, a circumferential direction, a first end (99) and a second end (98) opposite of the first end (99) along the axial direction. The turbine engine includes a propeller assembly (14) proximate to the first end including a plurality of blades (42) arranged in the circumferential direction disposed around an axial centerline (12), and a feathering mechanism (60) including a hollow piston rod (19). The feathering mechanism rotates the plurality of blades about a pitch axis (13) extended in the radial direction from the axial centerline. The turbine engine further includes a housing (45) proximate to the second end disposed in adjacent arrangement with the propeller assembly in the axial direction. The axial centerline is defined through the propeller assembly and the housing. The turbine engine further includes a beta tube assembly (100) extended through the hollow piston rod and at least partially through the housing in coaxial alignment with the axial centerline. The beta tube assembly defines an at least partially hollow walled pipe (101) extended along the axial direction. The beta tube assembly further defines a plurality of grooves (111, 112) extended along the axial direction proximate to the housing. A first groove (111) extends at least partially in the circumferential direction and along the axial direction to at least partially define a helix (114) corresponding to a rotatable range of the plurality of blades about the pitch axis, and a second groove (112) extends in the axial direction.