Abstract: An open-rotor gas turbine engine comprising a starter/generator, a first spool and a second spool, the second spool is of a lower pressure than the first spool; wherein the starter/generator is connected to the first and second spools via first and second clutches respectively. The method of operating the open-rotor engine comprises the step of supplying power to the starter/generator to drive the first spool via the first clutch to start the engine and, once the engine is self-propelling, a step of driving the starter/generator from the second spool via the second clutch to generate electricity.

Abstract: An open-rotor gas turbine engine comprising a starter/generator, a first spool and a second spool, the second spool is of a lower pressure than the first spool; wherein the starter/generator is connected to the first and second spools via first and second clutches respectively. The method of operating the open-rotor engine comprises the step of supplying power to the starter/generator to drive the first spool via the first clutch to start the engine and, once the engine is self-propelling, a step of driving the starter/generator from the second spool via the second clutch to generate electricity.

Abstract: A power transmission arrangement comprises a first power transmission member connectable to a first main shaft of an engine. The arrangement also includes a second power transmission member connectable to a second main shaft of the engine and to a third power transmission member. A coupling assembly is provided which has a selectable coupling condition to couple the first power transmission member to the second power transmission member to allow power to be transmitted from the third power transmission member to the first main shaft of the engine via the first power transmission member. The coupling assembly has a decoupling condition to decouple the first power transmission member from the second power transmission member to allow power to be transmitted from the main shaft of the engine to the third power transmission member via the second power transmission member.

Abstract: A generator assembly for a gas turbine engine. The assembly includes an electrical generator connected via a first sprag clutch to an accessory gearbox driven by the engine. The generator is also connected by a second sprag clutch to an air turbine connected to engine bleed valves which are selectively open when the engine speed falls below a predetermined level. The clutches are arranged such that the generator is driven at any time by the fastest rotating of the gearbox and turbine.

Abstract: A rotor assembly for a gas turbine engine compressor includes a rotor disc for mounting a plurality of radially extending rotor blades for rotation thereon, an annulus filler for securing to the disc to provide a radially inner airflow surface for air passing through the rotor assembly and a securing arrangement for securing the annulus filler to the rotor disc, the annulus filler being configured such that it is biased into a condition in which the securing arrangement mechanically retains the annulus filler on the disc, but is movable against its bias to allow the annulus filler to be removed from the disc.

Abstract: A power transmission arrangement comprises a first power transmission member connectable to a first main shaft of an engine. The arrangement also includes a second power transmission member connectable to a second main shaft of the engine and to a third power transmission member. A coupling assembly is provided which has a selectable coupling condition to couple the first power transmission member to the second power transmission member to allow power to be transmitted from the third power transmission member to the first main shaft of the engine via the first power transmission member. The coupling assembly has a decoupling condition to decouple the first power transmission member from the second power transmission member to allow power to be transmitted from the main shaft of the engine to the third power transmission member via the second power transmission member.

Abstract: An aircraft gas turbine engine including a first hydraulic pump connected to a starter motor and a second hydraulic pump connected to the high-pressure compressor. The engine being arranged such that during starting the starter motor drives the first pump, to pump hydraulic fluid to operate the second pump as a motor to drive the high pressure compressor. During running the first and second pumps are connected to the aircraft hydraulic system.