The invention relates to a module of a turbomachine of longitudinal axis X, the module comprising: ⋅—a rotary casing (31) that rotates about the longitudinal axis and bears a propeller (2; 20, 21, 22) which is provided with a plurality of blades (32); ⋅—a fixed casing (48) comprising a cylindrical wall (49) extending between an inner wall (40) and an outer wall (41) of the rotary casing (31); and, ⋅—a system (30) for changing the pitch of the blades of the propeller, mounted around the fixed casing and comprising: a control means (55) comprising a movable body (57) that is able to move axially on said fixed casing, at least one load transfer bearing (56) comprising an inner ring (65) that is connected to the movable body (57), and an outer ring (66); and a connection mechanism (61) for connecting the outer ring (66) to the blades of the propeller. According to the invention, the module further comprises a feathering device (70) for feathering the blades of the propeller, this device (70) comprising an annular row of springs (71) that are arranged around said fixed casing and extend axially, the springs (71) comprising first axial ends (72) that bear against a ferrule (51) of the fixed casing, and opposite second axial ends (73) that bear against said inner ring (65).

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.

The invention relates to a module of a turbomachine of longitudinal axis X, the module comprising: ⋅—a rotary casing (31) that rotates about the longitudinal axis and bears a propeller (2; 20, 21, 22) which is provided with a plurality of blades (32); ⋅—a fixed casing (48) comprising a cylindrical wall (49) extending between an inner wall (40) and an outer wall (41) of the rotary casing (31); and, ⋅—a system (30) for changing the pitch of the blades of the propeller, mounted around the fixed casing and comprising: a control means (55) comprising a movable body (57) that is able to move axially on said fixed casing, at least one load transfer bearing (56) comprising an inner ring (65) that is connected to the movable body (57), and an outer ring (66); and a connection mechanism (61) for connecting the outer ring (66) to the blades of the propeller. According to the invention, the module further comprises a feathering device (70) for feathering the blades of the propeller, this device (70) comprising an annular row of springs (71) that are arranged around said fixed casing and extend axially, the springs (71) comprising first axial ends (72) that bear against a ferrule (51) of the fixed casing, and opposite second axial ends (73) that bear against said inner ring (65).

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 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.

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 propeller control unit (PCU) for controlling pitch angles of blades of a propeller, has: a pitch angle actuator; a servo valve hydraulically connected to the pitch angle actuator and to a first hydraulic fluid source; and a feather valve having a body movable within a cavity, the feather valve having a first actuation port and a second actuation port both in fluid communication with the cavity, the body between the first actuation port and the second actuation port, the body being movable to selectively hydraulically connect the pitch angle actuator to the servo valve through the feather valve or to hydraulically connect the pitch angle actuator to a drain line through the feather valve, the first actuation port and the second actuation port hydraulically connected to a second hydraulic fluid source independent from the first hydraulic fluid source.

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 ducted fan module with variable-pitch blades for a turbo engine includes a rotor carrying a plurality of blades, a stationary casing, and a blade pitch changing and control system. The rotor includes a central shaft and a surrounding blade support ring. A front end of the blade support ring is connected to a front end of the central shaft, creating a rearward-opening annular space between the blade support ring and the central shaft. A tubular part is connected to the stationary casing and extends into the annular space.