A bleed air control system is configured to vary the air pressure at the inlet of a gas turbine engine. The bleed air control system includes a first gas turbine engine configured to provide bleed air, a second gas turbine engine acting as an auxiliary power unit, and a bleed air control system configured to selectively provide bleed air from the first gas turbine engine to the second gas turbine engine.

A system for supplying compressed air to a pneumatic network includes a load compressor, an air supply and a power shaft driving the load compressor. The system also includes in an air outlet of such load compressor, a connecting channel connected, on the one side, with a channel connected with the pneumatic network and, on the other side, with an air discharge conduct towards an exhaust nozzle. Air flow rate bleed valves are controlled by a processing unit via servo-loops as a function of the pressure sensors and the speed sensor.

A system is provided for multi-engine coordination of gas turbine engine motoring in an aircraft. The system includes a controller operable to determine a motoring mode as a selection between a single engine dry motoring mode and a multi-engine dry motoring mode based on at least one temperature of a plurality of gas turbine engines and initiate dry motoring based on the motoring mode.

The relative position and orientation between an auxiliary gearbox and a casing of an aircraft engine can be set including engaging a localizing feature of the accessory gearbox with a localizing feature of the casing; and a load path between auxiliary gearbox can subsequently be defined including securing at least two brackets between the accessory gearbox and casing.

The invention relates to a device for controlling an auxiliary engine (8) comprising a gas generator and a free turbine suitable for being able to be connected mechanically to the rotor (12) of a helicopter in order to supply it with thrust power, characterised in that said control device comprises a proportional-integral controller (30) having a proportional gain (Kp) and an integral gain (Ki), which are dependent on the rotation speed of said gas generator, said controller (30) being configured to receive an error signal representing a speed error of said free turbine, and to generate a signal (Sc) for correcting the drive speed of said gas generator obtained by adding a signal proportional to said error signal in accordance with said proportional gain (Kp), and an integrated signal (Si) resulting from the addition of a signal proportional to said error signal in accordance with said integral gain (Ki) and a memory signal (Sm), supplied by a feedback loop (31) of said integrated signal (Si), said memory signal (Sm) being dependent on a measurement representing the rotation speed of said free turbine.

A power generation system for a nuclear reactor includes an externally-heated turbine engine, a reactor heat exchanger, and a heat recuperating system. The externally-heated turbine engine produces compressed air that is heated by the reactor heat exchanger. The heat recuperating system includes a heat exchanger thermally connected to the externally-heated turbine engine to transfer heat to the compressed air to supplement the reactor heat exchanger.

This invention concerns an aircraft propulsion system in which an engine has an engine core comprising a compressor, a combustor and a turbine driven by a flow of combustion products of the combustor. At least one propulsive fan generates a mass flow of air to propel the aircraft. An electrical energy store is provided on board the aircraft. At least one electric motor is arranged to drive the propulsive fan and the engine core compressor. A controller controls the at least one electric motor to mitigate the creation of a contrail caused by the engine combustion products by altering the ratio of the mass flow of air by the propulsive fan to the flow of combustion products of the combustor. The at least one electric motor is controlled so as to selectively drive both the propulsive fan and engine core compressor.

A system and method for starting an aircraft turbine engine includes a primary starting subsystem and a secondary starting subsystem. The primary starting subsystem is coupled to a shaft of the aircraft turbine engine and has a dedicated power source. The secondary starting subsystem is also coupled to the shaft of the aircraft turbine engine and has a shared power source. A controller controls the operation of the primary starting subsystem and the secondary starting subsystem while starting the aircraft turbine engine. The primary starting subsystem may be an Auxiliary Power Unit coupled to an Air Turbine Starter. The secondary starting subsystem may be a Starter Generator coupled to a battery also used to power the Emergency Hydraulic System. The primary starting subsystem is always operated at full power during starting while the secondary starting subsystem is preferably operated in a sequence of different power levels.

A starter air valve has a valve member and an actuator. A rotary spool valve has a rotatable valve body and an outer housing to selectively provide three modes of operation for the starter air valve. A first mode of operation connects air through the rotatable valve body to communicate with an actuator control, and to receive air back from the actuator control. The rotatable valve body then communicates the air to the actuator. In a second mode the rotatable valve body blocks communication between the actuator control and the actuator, and delivers air through a variable area port in a wall of the rotatable valve body to bypass the valve member. In a third mode the rotatable valve body blocks communication between the actuator and the actuator control, and connects air to the actuator without having passed to the actuator control. A starter air system is also disclosed.

An air turbine starter that includes a housing. The housing can circumscribe a turbine coupled that is coupled to a gear train in a gear box via a drive shaft. The gear train can couple to an output shaft via at least a carrier. The air turbine starter can include at least a first bearing assembly and a second bearing assembly to rotatably support one or more of the drive shaft, the carrier, or the output shaft.