A system and method for blade angle position feedback. The system comprises an annular member operatively connected to rotate with a propeller, a sensor fixedly mounted adjacent the annular member and configured for detecting a passage of each singularity as the annular member is rotated and axially displaced and for generating a sensor signal accordingly, the annular member and sensor configured for relative axial displacement between a first relative axial position and a second relative axial position respectively corresponding to the first and the second mode of operation, and a detection unit connected to the sensor for receiving the sensor signal therefrom, determining on the basis of the sensor signal a time interval elapsed between the passage of successive singularities, and computing from the time interval blade angle position.

A system and method for providing feedback for an aircraft-bladed rotor about a longitudinal axis and having an adjustable blade pitch angle. At least one position marker is provided at the rotor, extends along an axial direction, from a first end to a second end, and has varying magnetic permeability from the first end to the second end. At least one sensor is coupled to the rotor and configured for producing, as the rotor rotates about the longitudinal axis, at least one sensor signal in response to detecting passage of the at least one position marker. A control unit is communicatively coupled to the at least one sensor and configured to generate a feedback signal indicative of the blade pitch angle in response to the at least one sensor signal received from the at least one sensor.

A pitch control system configured to vary a pitch angle of a plurality of propeller blades of a propeller system is provided including a motor having a motor shaft configured to rotate about an axis. A rotary switch having a tab protruding generally outwardly is coupled to the motor shaft and is configured to move between a first position and a second position. The pitch control system also includes a position sensor configured to monitor the position of the rotary switch. The position of the rotary switch is proportional to the pitch angle of the plurality of propeller blades.

A propeller hydraulic actuation system, includes a double-acting dual chamber hydraulic pitch change actuator. The pitch change actuator includes a first pressure circuit having first fluid supply lines and a first hydraulic chamber and a second pressure circuit having second fluid supply lines and a second hydraulic chamber. A piston separates the first and second chambers. At least one pressure sensor is provided for obtaining pressure measurements from which a load differential (F) applied to the piston by the circuits can be calculated. A closed loop controller is arranged to control the fluid supplied to the first and second pressure circuits, wherein the closed loop controller includes an actuator position loop arranged to utilise feedback on the actuator position to control the actuator position.

A blade angle feedback assembly for an aircraft-bladed rotor is provided. The rotor is rotatable about a longitudinal axis and having an adjustable blade pitch angle. The assembly comprises a feedback device coupled to rotate with the rotor with adjustment of the blade pitch angle, the feedback device comprising a non-magnetically permeable body defining a root surface and a plurality of magnetically permeable position markers circumferentially disposed on the root surface, and at least one sensor mounted adjacent the feedback device and configured to detect a passage of the plurality of position markers as the feedback device rotates about the longitudinal axis.

A system and method for detecting fixed pitch operation of a variable pitch propeller of an engine are provided. A command signal for maintaining a rotational speed of the propeller at a reference speed is output. An actual value of at least one of the rotational speed and a blade angle of the propeller is obtained. From the actual value, it is assessed whether an expected change in the at least one of the rotational speed and the blade angle of the propeller has occurred in response to the command signal. Responsive to determining that the expected change in the at least one of the rotational speed and the blade angle of the propeller has not occurred in response to the command signal, operation of the propeller at fixed pitch is detected and an alert output accordingly.

There is provided a blade angle feedback system for an aircraft-bladed rotor rotatable about a longitudinal axis and having an adjustable blade pitch angle. A feedback device is coupled to rotate with the rotor and to move along the axis with adjustment of the blade pitch angle. The feedback device comprises a body having position marker(s) embedded therein, the body made of a first material having a first magnetic permeability and the position marker(s) comprising a second material having a second magnetic permeability greater than the first. Sensor(s) are positioned adjacent the feedback device and configured for producing, as the feedback device rotates about the axis, sensor signal(s) in response to detecting passage of the position marker(s). A control unit is communicatively coupled to the sensor(s) and configured to generate a feedback signal indicative of the blade pitch angle in response to the sensor signal(s) received from the sensor(s).

Methods and systems for testing a sensor of a propeller blade angle position feedback system are described. A sensor signal is received from a sensor at a known position relative to a feedback device, the feedback comprising a ring and at least one pair of position markers spaced from one another around a circumference thereof, the sensor configured for successively detecting passage of the position markers as the feedback device rotates at a known rotational speed and an axial distance between the sensor and the feedback device varies. From the sensor signal a measured position of the sensor relative to the feedback device and a measured rotational speed of the feedback device are determined. The measured position and the measured rotational speed are compared to the known position and the known rotational speed to determine a sensor accuracy.

The test rig can be used for testing a blade pitch measurement system of a variable pitch propeller system. The test rig can include a first mount rotatably mounted to the frame and configured to receive the feedback device, a rotation motor drivingly coupled to rotate the ring mount relative to the frame around a rotation axis, a second mount configured to receive the pitch sensor, a mechanism configured for moving the second mount along an orientation parallel to the rotation axis, and a controller configured to control the rotation of the rotation motor to a variable rotation speed, and for controlling the movement of the second mount to variable positions via the mechanism.

A blade angle feedback assembly for an aircraft-bladed rotor is provided. The rotor is rotatable about a longitudinal axis and has an adjustable blade pitch angle. The assembly comprises a feedback device coupled to rotate with the rotor with adjustment of the blade pitch angle, the feedback device having a root surface, a plurality of position makers circumferentially disposed on the root surface, the plurality of position markers circumferentially spaced from one another and non-aligned with the longitudinal axis, and at least one sensor mounted adjacent the feedback device and configured to detect a passage of the plurality of position markers as the feedback device rotates about the longitudinal axis.