The present disclosure describes a propeller control unit for controlling the blade pitch of a propeller. The unit includes an electrohydraulic servo valve (“EHSV”) and is connected to a propeller actuator that adjusts the blade pitch of a propeller. The EHSV operates to allow pressurized fluid to flow from a pressurized fluid source to the actuator to adjust the blade pitch of the propeller in a flight pitch range and a ground pitch range, to allow pressurized fluid to flow from the source to the actuator to adjust the blade pitch of the propeller in a flight pitch range but not a ground pitch range, and to block the flow of pressurized fluid from the source to the actuator and drain pressurized fluid from the actuator to prevent adjustment of the blade pitch of the propeller in the flight pitch range or the ground pitch range.

A system for feathering a propeller assembly disposed within a housing of the propeller assembly has a sleeve defining an outer wall and one or more sleeve tabs 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, a retainer defining one or more retainer tabs extended inward in the radial direction, wherein the one or more retainer tabs is disposed between the outer wall and the one or more sleeve tabs of the sleeve along the axial direction, and a beta tube assembly extended through the sleeve along the axial direction. The beta tube assembly defines one or more internal walls. The one or more internal walls defines a hydraulic fluid transfer cavity in fluid communication with one or more hydraulic fluid transfer orifices.

A system for feathering a propeller assembly disposed within a housing of the propeller assembly has a sleeve defining an outer wall and one or more sleeve tabs 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, a retainer defining one or more retainer tabs extended inward in the radial direction, wherein the one or more retainer tabs is disposed between the outer wall and the one or more sleeve tabs of the sleeve along the axial direction, and a beta tube assembly extended through the sleeve along the axial direction. The beta tube assembly defines one or more internal walls. The one or more internal walls defines a hydraulic fluid transfer cavity in fluid communication with one or more hydraulic fluid transfer orifices.

The invention describes a system for controlling the cyclic setting of blades (1) of a turbine engine propeller, the blades (1) being arranged in a plane normal to the axis of rotation (r) of the propeller, the system comprising: —a plate assembly (40) that can be tilted relative to the normal plane (P), —an articulation system (50) articulating the plate assembly (40) relative to the blades (1) such that tilting the plate assembly (40) modifies the setting of the blades (1), —a force sensor (5) designed to measure a force applied in the normal plane (P) by an air flow at the inlet of the propeller blades (1), —a cylinder (60) suitable for tilting the plate assembly (40) in response to a force measured by the force sensor (5).

The invention describes a system for controlling the cyclic setting of blades (1) of a turbine engine propeller, the blades (1) being arranged in a plane normal to the axis of rotation (r) of the propeller, the system comprising: —a plate assembly (40) that can be tilted relative to the normal plane (P), —an articulation system (50) articulating the plate assembly (40) relative to the blades (1) such that tilting the plate assembly (40) modifies the setting of the blades (1), —a force sensor (5) designed to measure a force applied in the normal plane (P) by an air flow at the inlet of the propeller blades (1), —a cylinder (60) suitable for tilting the plate assembly (40) in response to a force measured by the force sensor (5).

A failure detection method and system for a propeller control unit coupled to a propeller are provided. An actual value of a blade angle and/or a rotational speed of the propeller are obtained. A comparison between the actual value and a threshold is performed. In response to determining, based on the comparison, that the actual value exceeds the threshold, the propeller control unit is caused to adjust the blade angle to bring the blade angle and/or the rotational speed towards the threshold. A subsequent actual value of the blade angle and/or the rotational speed is obtained. From the subsequent value, it is determined whether the blade angle and/or the rotational speed has been brought towards the threshold. In response to determining that the blade angle and/or the rotational speed has failed to be brought towards the threshold, failure of the propeller control unit is detected and an alert is output.

A failure detection method and system for a propeller control unit coupled to a propeller are provided. An actual value of a blade angle and/or a rotational speed of the propeller are obtained. A comparison between the actual value and a threshold is performed. In response to determining, based on the comparison, that the actual value exceeds the threshold, the propeller control unit is caused to adjust the blade angle to bring the blade angle and/or the rotational speed towards the threshold. A subsequent actual value of the blade angle and/or the rotational speed is obtained. From the subsequent value, it is determined whether the blade angle and/or the rotational speed has been brought towards the threshold. In response to determining that the blade angle and/or the rotational speed has failed to be brought towards the threshold, failure of the propeller control unit is detected and an alert is output.

A system for controlling a propeller having a plurality of blades having a primary control system and a backup control system. The primary control system including a sensor responsive to a propeller state, and a controller connected to the sensor and to an electrohydraulic control actuator. The electrohydraulic control actuator is connected via a bypass valve to a hydraulic actuator that controls at least a blade angle of a blade of the propeller. The controller generating commands to the electrohydraulic control actuator based on at least the propeller state. The backup control system including a second controller, an electrohydraulic solenoid operably connected to the bypass valve. The backup control system is operable to hydraulically disable the primary control system via the bypass valve upon the occurrence of a selected condition, the second controller modulates the operation of the electrohydraulic solenoid to control the bypass actuator based on the propeller state.

A system for controlling a propeller having a plurality of blades having a primary control system and a backup control system. The primary control system including a sensor responsive to a propeller state, and a controller connected to the sensor and to an electrohydraulic control actuator. The electrohydraulic control actuator is connected via a bypass valve to a hydraulic actuator that controls at least a blade angle of a blade of the propeller. The controller generating commands to the electrohydraulic control actuator based on at least the propeller state. The backup control system including a second controller, an electrohydraulic solenoid operably connected to the bypass valve. The backup control system is operable to hydraulically disable the primary control system via the bypass valve upon the occurrence of a selected condition, the second controller modulates the operation of the electrohydraulic solenoid to control the bypass actuator based on the propeller state.

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, and sensing an axial movement of the transfer tube with the blade angle unit.