Systems and methods are described for governing the speed of a propeller on a propeller-based engine in an aircraft. The method comprises obtaining a synthesized or estimated blade angle for the propeller of the engine, determining one or more gain for a controller of the propeller based on the synthesized or estimated blade angle and one or more engine or aircraft parameter, determining a difference between a reference propeller speed and an actual propeller speed, applying the one or more gain to the difference via the controller in order to generate a command signal for controlling the propeller, and governing the propeller of the engine using the command signal.

A propeller control unit (PCU) has: a pitch angle actuator; a valve operable to selectively fluidly connect the pitch angle actuator with a source of oil for controlling pitch angles of blades of a propeller and with a drain line for draining oil out of the pitch angle actuator for feathering the blades; and a bypass line having an inlet hydraulically between the valve and an inlet of the drain line, the bypass line having an outlet hydraulically between the inlet of the drain line and an outlet of the drain line.

A control system (50) for a turbopropeller engine (2) of an aircraft (1) having a gas turbine (11) and a propeller assembly (3) coupled to the gas turbine (11), the gas turbine (11) having a compressor (12) coupled to an air intake (13) and a temperature sensor (22) being arranged in the air intake (13) to measure the temperature of engine intake air and provide a sensed temperature (T1.sub.sens); the control system envisages: a compensation system (40) to receive the sensed temperature (T1.sub.sens) from the temperature sensor (22) and to add to the sensed temperature (T1.sub.sens) a compensation quantity (comp) to compensate for a delay introduced by the time constant (τ) of the temperature sensor (22) and generate a compensated temperature (T1.sub.comp); and a control unit (20) to perform engine control operations based on the compensated temperature (T1.sub.comp). In particular, the compensation quantity (comp) is calculated based on an ISA International Standard Atmosphere—temperature (T1.sub.ISA), which is determined as a function of an external pressure (P0) measured by a pressure sensor (35).

Methods and system are described for operating an aircraft powerplant comprising an engine coupled to a variable-pitch propeller. The method comprises receiving a request to change a propeller rotational speed from a first setting to a second setting, determining a power need for the engine, when the power need corresponds to the second setting, modifying a command for at least one of fuel flow to the engine and oil flow to the propeller to govern the powerplant in accordance with the second setting for the propeller rotational speed, and when the power need does not correspond to the second setting, overriding the request to change the propeller rotational speed from the first setting to the second setting.

Methods and system are described for operating an aircraft powerplant comprising an engine coupled to a variable-pitch propeller. The method comprises receiving a request to change a propeller rotational speed from a first setting to a second setting, determining a power need for the engine, when the power need corresponds to the second setting, modifying a command for at least one of fuel flow to the engine and oil flow to the propeller to govern the powerplant in accordance with the second setting for the propeller rotational speed, and when the power need does not correspond to the second setting, overriding the request to change the propeller rotational speed from the first setting to the second setting.

A variable pitch propeller assembly operatively coupled with an engine and methods for controlling the pitch of a plurality of propeller blades thereof is provided. In one example aspect, the variable pitch propeller assembly includes features for combining overspeed, feathering, and reverse functionality in a single secondary control valve. The secondary control valve is operable to selectively allow a controlled amount of hydraulic fluid to flow to or from a pitch actuation assembly such that the pitch of the propeller blades can be adjusted to operate the variable pitch propeller assembly in one of a constant speed mode, a feather mode, and a reverse mode.

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.

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).

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 feedback device for use in a gas turbine engine, and methods and systems for controlling a pitch for an aircraft-bladed rotor, are provided. The feedback device is composed of a circular disk and a plurality of position markers. The circular disk is coupled to rotate with a rotor of the gas turbine engine, to move along a longitudinal axis of the rotor, and has first and second opposing faces defining a root surface that extends between and circumscribes the first and second faces. The plurality of position markers extend radially from the root surface and are circumferentially spaced around the circular disk. The position markers have a top surface elevated with respect to the root surface and opposing first and second side surfaces. The side surfaces of the position markers have a curved concave profile extending toward the root surface.