Low latency pitch adjustable rotors are disclosed. A disclosed example rotor includes a rotor hub to rotate about a rotational axis, rotor blades coupled to the rotor hub, the rotor blades being pitch adjustable and having corresponding pitch angles, and a reaction hinge operatively coupled between the rotor hub and the rotor blades, the reaction hinge to move relative to the rotor hub in response to an angular acceleration or deceleration of the rotor hub to adjust the pitch angles.

There is provided a blade angle feedback assembly for an aircraft-bladed rotor rotatable about a longitudinal axis and having an adjustable blade pitch angle. The assembly comprises a feedback device coupled to rotate with the rotor, the feedback device having a root surface having a first edge, first position markers extending from the root surface and oriented substantially parallel to the axis, the first position markers circumferentially spaced from one another, at least one second position marker extending from the root surface and positioned between two adjacent first position markers at an angle thereto, the at least one second position marker having an end positioned adjacent to the first edge and non-flush therewith, and at least one sensor mounted adjacent the feedback device and configured to detect a passage of the first position markers and the at least one second position marker as the feedback device rotates about the axis.

Herein provided is a phonic wheel for use in a gas turbine engine and associated systems and methods. The phonic wheel comprises a circular disk having first and second opposing faces. The circular disk defines a root surface that extends between and circumscribes the first and second faces. A first plurality of projections extend from the root surface and are oriented substantially parallel to an axis of rotation of the disk. The first plurality of projections are circumferentially spaced substantially equally from one another and each have a first physical configuration. At least one second projection extends from the root surface and is positioned between two adjacent first projections, the at least one second projection having a second physical configuration different from the first physical configuration.

A blade angle feedback assembly for an aircraft-bladed rotor and an aircraft-bladed rotor system are provided. The rotor is rotatable about a longitudinal axis and has an adjustable blade pitch angle. A feedback device is coupled to rotate with the rotor , the feedback device having a root surface having an edge. At least one position marker extends from the root surface and extends laterally beyond the edge. At least one sensor is mounted adjacent the feedback device and configured to detect a passage of the at least one position marker as the feedback device rotates about the longitudinal axis.

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.

Herein provided are systems and methods for synchrophasing multi-engine aircraft. A phonic wheel is coupled to a first propeller of a first engine of the aircraft. A sensor is disposed and configured for producing a signal in response to passage of first and second position markers on the phonic wheel. A control system is communicatively coupled to the sensor for obtaining the signal, and configured for: determining an expected delay between two subsequent signal pulses of the signal; identifying from within the plurality of signal pulses a particular pulse associated with the second position marker; determining, based on a particular time at which the particular pulse associated with the second position marker was produced, that a rotational position of the first propeller corresponds to a reference position at the particular time; and performing at least one synchrophasing operation for the aircraft based on the rotational position of the first propeller.

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.

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 control system for an aircraft propeller rotatable about a longitudinal axis and having an adjustable blade angle is provided. A blade angle feedback ring is coupled to the propeller to rotate with the propeller and to move along the longitudinal axis along with adjustment of the blade angle. The feedback ring includes position markers spaced around its circumference. A sensor is positioned adjacent the feedback ring for producing signals indicative of passage of the position markers. A controller is in communication with the sensor, and is configured for: measuring a distance between the position markers, wherein the distance is representative of a longitudinal position of the feedback ring; determining whether a value representative of the longitudinal position is within a first threshold range; and when the value is within the first threshold range, storing the value as a calibration value associated with the blade angle feedback ring.

Systems and methods for controlling a gas turbine engine and a propeller are described herein. A target output power for the engine and a target speed for the propeller are received. A measurements of at least one engine parameter and a measurement of at least one propeller parameter are received. At least one engine control command is generated based on the target output power, the measurement of the at least one engine parameter and at least one model of the engine. At least one propeller control command is generated based on the target speed, the measurement of the at least one propeller parameter and the at least one model of the propeller. The at least one engine control command is output for controlling an operation of the engine accordingly and the at least one propeller control command is output for controlling an operation of the propeller accordingly.