An aircraft cabin blower system comprises a cabin blower including a compressor configured to provide air to a cabin of the aircraft; a variable drive system configured to drive the compressor and including an electric variator and a summing gearbox; and a main transmission configured, when operating in a blower mode, to receive mechanical power from a gas turbine engine and input mechanical power to the summing gearbox in a forward direction; and configured, when operating in a starter mode, to receive mechanical power from the summing gearbox and input mechanical power to the gas turbine engine. The aircraft cabin blower system further includes a first one-way rotation device adapted to permit free rotation of the main transmission in the forward direction and to prevent rotation of the main transmission in a reverse direction opposite to the forward direction.

An architecture for an aircraft comprises two air-conditioning systems, two converters, each intended to supply one of the air-conditioning systems, and at least one first electric machine which starts up a first main engine of the aircraft. The electrical architecture is configured such that the two converters can together supply the first electric machine. A method of operating the architecture is also provided.

A system and method for improved system efficiency of an integrated power and control unit (IPCU) of an aircraft is disclosed. The system uses an open-loop cooling system and turbo machine power matching to provide wide operation range without over-sizing. In order to reduce the temperature of the air flow through the cooling heat exchanger, the cooling turbine need to expand further in the same time generating power but the power could be higher than the compressor could absorb so a generator that would convert the power and used in supplying the aircraft would result in more efficient system.

An aircraft cabin blower system is described having a hydraulic circuit comprising a first hydraulic device and a second hydraulic device. The first hydraulic device is mechanically coupled to a cabin blower compressor and the second hydraulic device is arranged in use to be mechanically coupled to a spool of a gas turbine engine. The first hydraulic device is capable of performing as a hydraulic motor and the second hydraulic device is capable of performing as a hydraulic pump. When, in use, the system is operating in a cabin blower configuration, a driving force supplied by the spool of the gas turbine causes the second hydraulic device to pump liquid provided in the hydraulic circuit and thereby to drive the first hydraulic device, which in turn rotates the cabin blower compressor.

An aircraft propulsion system includes a gas turbine engine; an environmental control system (ECS); and a bleed flowpath from the gas turbine engine through the ECS. A turbine is along the bleed flowpath and a propulsion fan is mechanically coupled to the turbine to be driven by the turbine.

There is provided a blower system for providing air to an airframe system, comprising a rotor configured to be mechanically coupled to a spool 440 of a gas turbine engine, wherein the rotor is configured to: in a blower mode, be driven to rotate by the spool to discharge air to an airframe discharge port for supply to an airframe system; and, in an engine drive mode, receive air from an external air source via an impingement port that is configured to direct the received air onto the rotor and thereby drive the rotor to rotate to drive the spool to.

An aircraft cabin blower system comprises a cabin blower including a compressor configured to provide air to a cabin of the aircraft; a variable drive system configured to drive the compressor and including an electric variator and a summing gearbox; and a main transmission configured, when operating in a blower mode, to receive mechanical power from a gas turbine engine and input mechanical power to the summing gearbox in a forward direction; and configured, when operating in a starter mode, to receive mechanical power from the summing gearbox and input mechanical power to the gas turbine engine. The aircraft cabin blower system further includes a first one-way rotation device adapted to permit free rotation of the main transmission in the forward direction and to prevent rotation of the main transmission in a reverse direction opposite to the forward direction.

The invention relates to an aircraft incorporating an enhanced power unit for generating electric, pneumatic and/or hydraulic power for the aircraft during all stages of the aircraft operation. The power unit (1) comprises: a heat engine (14) with a drive shaft (2) and a combustion gases exhaust (7). The power unit (1) also includes a Rankine cycle system (12) for recovering thermal energy from a heat source of the power unit (1) for the assistance of the heat engine (14). The heat source for the Rankine cycle system can be taken from the exhaust gases of the heat engine, from the oil coolant circuit of the heat engine or from the output of a compressor driven by the heat engine. Preferably, the aircraft cabin air is reused as a source of oxygen for the combustion. The invention reduces bleed air extraction from the aircraft main engines thereby reducing fuel consumption.

A method of operating a gas turbine engine compressor. The engine comprises a compressor having an environmental control system bleed port having an outlet in fluid communication with an aircraft environmental control system air duct, and an air turbine starter configured to rotate a compressor shaft of the gas turbine engine. The air turbine starter has an inlet in fluid communication with the environmental control system air duct via an air turbine valve. The method comprises determining a surge margin of the compressor, and where the surge margin of the compressor is determined to be below a predetermined minimum surge margin, opening the air turbine valve to supply air to the air turbine.

Pressurized air systems for aircraft and related methods are described herein. An example pressurized air system includes a compressor having a compressor inlet and a compressor outlet. The compressor inlet receives air from a first air source and the compressor outlet supplies pressurized air to an environmental control system (ECS). The pressurized air system includes a turbine having a turbine inlet to receive air from a second air source, a first overrunning clutch operatively coupled between an output shaft of an accessory gearbox and the compressor, the accessory gearbox operatively coupled to a drive shaft extending from an engine of the aircraft, and a second overrunning clutch operatively coupled between the compressor and the turbine. The first and second overrunning clutches enable the accessory gearbox to drive the compressor during a first mode of operation and enable the turbine to drive the compressor during a second mode of operation.