A system and method for feathering an aircraft propeller are provided. The aircraft propeller is coupled to an actuator for setting a blade pitch of the propeller. The blade pitch is controlled by modulating a supply of hydraulic fluid to the actuator. At least one feather solenoid is provided that comprises a first solenoid coil, a second solenoid coil, and a solenoid valve coupled to the actuator and to the first and the second solenoid coil. At least one controller is configured to selectively energize and de-energize the first and the second solenoid coil. The solenoid valve is configured to be activated when the first solenoid coil and the second solenoid coil are de-energized and to, when activated, modulate the supply of hydraulic fluid to the actuator for adjusting the blade pitch of the propeller towards a feather position.

A system and method for feathering an aircraft propeller are provided. A first feather solenoid and a second feather solenoid each comprising at least one solenoid coil and a solenoid valve coupled to the actuator and to the at least one solenoid coil are provided. At least one controller is configured to selectively energize and de-energize the at least one solenoid coil. The solenoid valve of the first feather solenoid is configured to be activated when the at least one solenoid coil of the first feather solenoid is energized and the solenoid valve of the second feather solenoid is configured to be activated when the at least one solenoid coil of the second feather solenoid is de-energized. The solenoid valve is configured to, when activated, modulate the supply of hydraulic fluid to an actuator for adjusting a blade pitch of the propeller towards a feather position.

A brake unit comprises said rotor disc rotatable about a central axis of rotation; a first brake pad mounting means having a first end and a second end and a longitudinal outer, side, surface extending there between, wherein a first brake pad is provided at said first end of said first brake pad mounting means and positioned facing a first face of said rotor disc. The first brake pad mounting means comprises a first locking feature provided on its outer, side, surface. The brake unit further comprises first locking means configured to pivot about an axis, the locking means being configured to be movable about said pivot axis so that a locking feature of said locking means can come into contact with, or be moved away from said outer, side, surface of said first brake pad mounting means.

A method and system for controlling a pitch of blades of a fan assembly having a centerline axis of rotation is provided. The system includes a pitch change mechanism (PCM) including a hydraulic actuator positioned axisymmetric with respect to the fan assembly and configured to angularly displace the blades of the fan assembly between a first position and a second position. The PCM further includes a plurality of hydraulic fluid supply lines coupled in flow communication between the hydraulic actuator and a hydraulic fluid transfer sleeve, the hydraulic fluid transfer sleeve configured to transfer a flow of pressurized hydraulic fluid across a gap between a stationary member of the hydraulic fluid transfer sleeve and a rotatable member of the hydraulic fluid transfer sleeve.

The present disclosure is directed to a system 100 for feathering a propeller assembly 14, wherein the system is disposed within a housing 47 of the propeller assembly. The system 100 includes a sleeve 110 defining an outer wall 111 and one or more sleeve tabs 115 extended outward in a radial direction along at least a circumferential portion of the sleeve, wherein the one or more sleeve tabs is separated from the outer wall in an axial direction. The system 100 further includes a retainer 120 defining one or more retainer tabs 125 extended inward in the radial direction, wherein the one or more retainer tabs is disposed between the outer wall 111 and the one or more sleeve tabs 115 of the sleeve 110 along the axial direction. Still further, the system includes a beta tube assembly 130 extended through the sleeve along the axial direction, wherein the beta tube assembly defines one or more internal walls 131, wherein the one or more internal walls defines a hydraulic fluid transfer cavity 132 in fluid communication with one or more hydraulic fluid transfer orifices 133.

A sensor signal produced by a sensor as a feedback device rotates with a propeller about an axis and moves along the axis with adjustment of a blade angle of the propeller is received, the sensor signal indicative of a rotational speed and of the blade angle of the propeller. From the sensor signal, it is determined whether the rotational speed is within a predetermined range of a reference speed and an expected change in the blade angle has occurred in response to a command to adjust the blade angle to maintain the rotational speed at the reference speed. In response to determining that the rotational speed is within the predetermined range of the reference speed and the expected change in the blade angle has failed to occur in response to the command, inoperable movement of the feedback device along the axis is determined and an alert is output.

A control circuit for changing the angle of propeller blades includes a propeller control unit controlling a supply of oil to modify an angle of propeller blades, and a fixed-displacement pump providing the supply of oil from an engine oil return system to the propeller control unit. An oil cooling line extends between an outlet of the pump and the engine oil return system. The oil cooling line defines an oil leakage path leading to the engine oil return system for cooling the oil. A flow regulator between the pump and the propeller control unit is operable between an open position where oil is directed through the oil cooling line to the engine oil return system for cooling the oil, and a closed position blocking the oil cooling line and directing oil toward the propeller control unit to modify the angle of the propeller blades.

A method of controlling a propeller assembly, having a blade, piston end cap, and piston, with a pitch control unit, having a transfer bearing and a blade angle unit, the method comprising: axially moving a transfer tube relative to and circumscribing the transfer bearing, sensing an axial movement of the transfer tube with the blade angle unit.

There is described herein the automation of propeller feather testing functions, whereby the test is automatically performed and a pass/fail signal is issued upon completion.

A propeller pitch control actuation system includes a relatively lightweight, relatively inexpensive means for selectively preventing the propeller pitch control actuator from commanding reverse pitch positions.