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, are circumferentially spaced around the circular disk, and extending along the longitudinal axis from a first end portion to a second end portion. At least part of the first end portion and/or of the second end portion comprises a material having higher magnetic permeability than that of a remainder of the position markers.

An electronic controller for an engine and a propeller, a control system and related methods are described herein. The control system comprises the controller having a first channel and a second channel independent from and redundant to the first channel. Each channel comprises a control processor configured to receive first engine and propeller parameters and to output, based on the first engine and propeller parameters, at least one engine control command and at least one propeller control command. Each channel also comprises a protection processor configured to receive second engine and propeller parameters and to output, based on the second engine and propeller parameters, at least one engine protection command and at least one propeller protection command. The control system comprises sensors for measuring the parameters of the engine and/or the propeller and effectors configured to control the engine and the propeller.

An electronic controller for an engine and a propeller, a control system and related methods are described herein. The control system comprises the controller having a first channel and a second channel independent from and redundant to the first channel. Each channel comprises a control processor configured to receive first engine and propeller parameters and to output, based on the first engine and propeller parameters, at least one engine control command and at least one propeller control command. Each channel also comprises a protection processor configured to receive second engine and propeller parameters and to output, based on the second engine and propeller parameters, at least one engine protection command and at least one propeller protection command. The control system comprises sensors for measuring the parameters of the engine and/or the propeller and effectors configured to control the engine and the propeller.

A fan system includes a rotor having plurality of blades and a ring airfoil, the plurality of blades being rotatably joined to a hub and the ring airfoil. The fan system may include a second contra-rotationally disposed rotor having a plurality of blades and a ring airfoil. The first and second ring airfoils having a cambered shape and an angle of attack between about 5 degrees and about 45 degrees. Passive leading edge slats are attached to the ring airfoil and are configured to open and close using springs.

A fan system includes a rotor having plurality of blades and a ring airfoil, the plurality of blades being rotatably joined to a hub and the ring airfoil. The fan system may include a second contra-rotationally disposed rotor having a plurality of blades and a ring airfoil. The first and second ring airfoils having a cambered shape and an angle of attack between about 5 degrees and about 45 degrees. Passive leading edge slats are attached to the ring airfoil and are configured to open and close using springs.

A method for controlling an aircraft propeller is provided that comprises obtaining a measurement of a speed of the propeller, comparing the propeller speed to a first threshold, responsive to determining that the propeller speed exceeds the speed threshold, outputting a valve control signal for opening a two-position solenoid valve coupled to the propeller, the two-position solenoid valve configured for controlling fluid flow to and from the propeller to control propeller blade angle, computing a rate of change of the propeller speed, comparing the rate of change of the propeller speed to a second threshold, and responsive to determining that the rate of change of the propeller speed is below the second threshold, outputting the valve control signal for closing the two-position solenoid valve. A system for controlling an aircraft propeller and an aircraft propeller control assembly are also provided.

There is provided a method and system for operating a turboprop engine of an aircraft. When a resulting value for Ng is between at least one upper limit and at least one lower limit, the output power is governed as a function of the target power. When the resulting value for Ng is on or outside of the at least one upper limit and the at least one lower limit, the output power is governed as a function of the maximum Ng and the minimum Ng.

An electronic control system (35) for a turbopropeller (2) having a gas turbine engine (20) and a propeller assembly (3) coupled to the gas turbine engine (20), the control system (35) having: a propeller control stage (35a), implementing a closed loop control for controlling operation of the propeller assembly (3) based on a scheduled propeller speed reference (Nr.sub.ref) and a propeller speed measure (Nr); a gas turbine control stage (35b), implementing a closed loop control for controlling operation of the gas turbine engine (20) based on a scheduled reference (Ngdot.sub.ref) and at least a feedback quantity. The control system (35) further envisages an auxiliary control stage (35c), coupling the propeller control stage (35a) and the gas turbine control stage (35b) and determining a limitation of the operation of the gas turbine engine (20), if a propeller speed overshoot is detected, with respect to the propeller speed reference (Nr.sub.ref).

An electronic control system (35) for a turbopropeller (2) having a gas turbine engine (20) and a propeller assembly (3) coupled to the gas turbine engine (20), the control system (35) having: a propeller control stage (35a), implementing a closed loop control for controlling operation of the propeller assembly (3) based on a scheduled propeller speed reference (Nr.sub.ref) and a propeller speed measure (Nr); a gas turbine control stage (35b), implementing a closed loop control for controlling operation of the gas turbine engine (20) based on a scheduled reference (Ngdot.sub.ref) and at least a feedback quantity. The control system (35) further envisages an auxiliary control stage (35c), coupling the propeller control stage (35a) and the gas turbine control stage (35b) and determining a limitation of the operation of the gas turbine engine (20), if a propeller speed overshoot is detected, with respect to the propeller speed reference (Nr.sub.ref).

An electronic control system (30) for a turbopropeller engine (12) having a gas turbine (20) and a propeller assembly (13) coupled to the gas turbine (20), controls propeller operation based on a pilot input request, via generation of a driving quantity (Ip) for an actuation assembly (29) designed to adjust a pitch angle () of propeller blades (2) of the propeller assembly (13). The control system (30) envisages: a propeller speed regulator (39), receiving at its input a propeller speed error (ep), indicative of a difference between a propeller speed measure (Nr) and a propeller speed demand (Nrref), and generating at its output, based on the propeller speed error (ep), a first control quantity (Outi); a propeller pitch regulator (42), receiving at its input a propeller pitch error (ep), indicative of a difference between a propeller pitch demand ( ) and a pitch position measure (), and generating at its output, based on the propeller pitch error (ep), a first control quantity (Out2); and a priority selection stage (45), configured to implement a priority selection between the first and the second control quantities, for providing at the output the driving quantity (IP), based on the priority selection between the first and the second control quantities.