A gas turbine engine comprises a gearbox including a first epicyclic gearbox and a second epicyclic gearbox. The first epicyclic gearbox comprises a first sun gear meshing with the first planet gears and the first planet gears meshing with a first annulus gear. The second epicyclic gearbox comprises a second sun gear meshing with the second planet gears and the second planet gears meshing with a second annulus gear. An input shaft is arranged to drive the first sun gear and a first planet gear carrier is arranged to drive a propulsor. The first and second annulus gears are fixed to a static structure. A first clutch is arranged between the first planet gear carrier and the second planet gear carrier and a second clutch is arranged between the second sun gear and the input shaft. The gearbox is more efficient at cruise conditions.

An unducted thrust producing system, includes a rotating element, a stationary element. An inlet may be located forward or aft of the rotating element and the stationary element. An exhaust may be located forward, aft, or between the rotating element and the stationary element.

An aviation turbine engine having at least one unducted rotary propeller having a plurality of blades, each blade including: a blade body made of composite material including fiber reinforcement densified by a matrix, the fiber reinforcement of the blade body presenting three-dimensional weaving, the body extending between a leading edge and a trailing edge, and a protective fitting for protecting the leading edge and made of composite material having fiber reinforcement densified by a matrix, the fitting being adhesively bonded onto the leading edge of the blade body, the fitting being formed from a dry fiber preform injection molded with a densifying resin, and a polyurethane film for providing protection against erosion covering the blade body and the fitting.

A pitch actuation system for a turbine engine propeller includes an actuator with movable part configured to rotate the blades of the propeller relative to the blade pitch axes. The actuator includes a transmission screw that is rotatable and movable in translation along a longitudinal axis, and a nut that engages the screw to move in translation along the longitudinal axis to adjust the pitch of the propeller blades. The actuator further includes non-rotatable decoupler for decoupling the rotation between the propeller and the nut. A blade feathering device has at least one electric drive motor and is configured to translate a member along the longitudinal axis. A blade pitch control device includes at least one electric motor configured to drive a rotor about the longitudinal axis, wherein that rotation rotates the screw and transmits translation of the member.

A unshrouded vane assembly for an unducted propulsion system includes a plurality of vanes which have non-uniform characteristics configured to generate a desired vane exit swirl angle.

An annulus filler may include an outer lid defining an airflow surface for air being drawn through the engine in an axial airflow direction and a support structure configured to connect the outer lid to a rotor disc. The annulus filler may include a composite material including a plurality of relatively high-modulus reinforcement elements, a plurality of relatively tough polymer-based reinforcement elements, and a matrix material substantially encapsulating the plurality of relatively high-modulus reinforcement elements and the plurality of relatively tough reinforcement elements.

The present disclosure is directed to a turbine engine (10) defining an axial direction and a radial direction. The turbine engine includes a fan or propeller assembly (14) comprising a gearbox; an engine core (20) comprising one or more rotors, wherein at least one of the rotors defines an axially extended annular hub; and a flexible coupling shaft (100) defining a first end and a second end along the axial direction, wherein the first end is connected to the engine core and the second end is connected to the gearbox, and further wherein the flexible coupling shaft extends from the one or more rotors to the gearbox in the axial direction and inward of the hub in the radial direction.

A method and a system are provided for controlling a propeller-driven aircraft, the aircraft powered by at least one engine having at least one propeller associated therewith. At least one control input for the at least one engine is received at an engine controller for the at least one engine. The engine controller determines, based on the at least one control input, a setpoint for a rotational speed of the at least one propeller and outputs, to a propeller controller for the at least one propeller, a control signal comprising instructions to adjust the rotational speed of the at least one propeller to the setpoint.

A speed reducer includes two intermediate lines for a turboprop engine, the reducer including: an input line including an input shaft bearing an input gear wheel, a first intermediate line including a first intermediate shaft bearing a first intermediate gear wheel, a second intermediate line including a second intermediate shaft bearing a second intermediate gear wheel, a spring held by a frame, the spring surrounding a longitudinal portion of the input shaft in order to allow a movement of the input gear wheel towards an equilibrium position corresponding to an equal distribution of the transmission of the power coming from the input shaft to the first intermediate shaft of the first intermediate line and the second intermediate shaft of the second intermediate line.

A hybrid gas-electric turbine engine for turboprop or turboshaft applications is disclosed together with associated methods. In various embodiments disclosed herein, the turbine engine comprises a turbine configured to be driven by a flow of combustion gas; a turbine shaft configured to be driven by the turbine and transfer power to a load coupled to the turbine engine and an electric motor configured to transfer power to the load coupled to the turbine engine. The rotor may have a rotor axis of rotation that is radially offset from a shaft axis of rotation of the turbine shaft. In some embodiments, the electric motor may be a multi-rotor electric motor.