An engine assembly defining an axial direction (A) and including a gearbox, an engine core including at least one rotor, and a flexible coupling shaft having a first end and a second end along the axial direction (A). The first end of the flexible coupling shaft is connected to the engine core and the second end of the flexible coupling shaft is connected to the gearbox. A damper system is positioned at the second end of the flexible coupling shaft. The damper system is configured to reduce vibrations to the flexible coupling shaft during operation of the engine assembly.

A gas turbine engine includes a first spool rotationally coupled to a plurality of accessories via a first gearing and a second spool rotationally coupled to a third spool via a second gearing. The first gearing and the second gearing rotate independently and are enclosed within a housing of an accessory gearbox. A method of operating the gas turbine engine includes supplying a first fuel flow rate to a primary combustor associated with the first and third spools and supply a second fuel flow rate a secondary combustor associated with the second spool based on a power lever angle within an intermediate power level range.

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 for controlling a pitch angle of blades of a cooling fan of associated with a radiator of an engine, the blades extending radially from a central hub, the fan having an axis. The method includes regulating a pitch angle of the blades from a first limit value for which a cooling flux of the cooling fan has a first value to a second limit value for which the cooling flux has a second value greater than the first value. The pitch angle is determined based on quantities measured in the engine. The method further includes steps of detecting an engine speed; calculating a first derivative of the engine speed to detect accelerations of the engine; comparing the calculated first derivative with a threshold value and if the calculated first derivative is greater than the threshold value, setting the pitch angle to the first minimum limit value.

A method of identifying a fuel contained in a fuel tank of an aircraft and arranged to power a gas turbine engine of the aircraft is performed by processing circuitry of the aircraft and includes: obtaining at least one fuel characteristic of any fuel already present in the fuel tank prior to refuelling; determining at least one fuel characteristic of a fuel added to the fuel tank on refuelling; and calculating at least one fuel characteristic of the resultant fuel in the fuel tank after refuelling. The method may further controlling the propulsion system of the aircraft based on the calculated at least one fuel characteristic of the resultant fuel in the fuel tank after refuelling.

An operation control device for a single shaft gas turbine selects an operation mode based on a load state of a power generator, and controls the turbine based on the operation mode. In a first operation mode, a rotational speed of the turbine is maintained within a first rotational speed range, and in a second operation mode, the rotational speed is maintained within a second rotational speed range set on a lower rotational speed side than the first rotational speed range. The second rotational speed range is set on the lower rotational speed side than the first rotational speed range with a first non-selection rotational speed range set therebetween.

Control systems and methods suitable for combination with power production systems and methods are provided herein. The control systems and methods may be used with, for example, closed power cycles as well as semi-closed power cycles. The combined control systems and methods and power production systems and methods can provide dynamic control of the power production systems and methods that can be carried out automatically based upon inputs received by controllers and outputs from the controllers to one or more components of the power production systems.

A fuel system for an aircraft engine comprises a fuel metering unit and a separate flow divider. The flow divider has an inlet port fluidly connected to the fuel metering unit via a fuel line. A primary and a secondary fuel manifold are fluidly connected to the flow divider. The fuel metering unit and the flow divider have a fuel supply mode in which fuel is allowed to flow in a first direction through the fuel line from the fuel metering unit to the flow divider to feed the primary and secondary fuel manifolds, and an ecology mode in which fuel is allowed to flow in a second direction through the same fuel line from the flow divider towards the fuel metering unit. A same fuel line is thus used as a fuel supply line and an ecology line.

An engine bleed control system for a gas turbine engine of an aircraft is provided. The engine bleed control system includes an engine bleed tap coupled to a fan-air source or a compressor source of a lower pressure compressor section before a highest pressure compressor section of the gas turbine engine and a motorized compressor in fluid communication with the engine bleed tap. The engine bleed control system also includes a controller operable to selectively drive the motorized compressor to boost a bleed air pressure as pressure augmented bleed air and control delivery of the pressure augmented bleed air to an aircraft use.

An aircraft propulsion system is disclosed and includes a first gas turbine engine including a first input shaft driving a first gear system, a first fan driven by the first gear system, a first generator supported on the first input shaft and a fan drive electric motor providing a drive input to the first fan, a second gas turbine engine including a second input shaft driving a second gear system, a second fan driven by the second gear system, a second generator supported on the second input shaft and a second fan drive electric motor providing a drive input to the second fan and a controller controlling power output from each of the first and second generators and directing the power output between each of the first and second fan drive electric motors.