Abstract: A propulsion system for use with an aircraft includes a gas turbine engine, an electric power system, and at least one propulsor. The gas turbine engine includes a compressor, a combustor, and a turbine. The electric power system includes a generator coupled to the gas turbine engine to generate electrical energy, power electronics connected to the generator to receive the electrical energy from the generator, and a motor configured to produce rotational energy in response to receiving electric energy from the power electronics. The propulsor is configured to use rotational energy received from the motor of the electric power system to generate thrust for propelling the aircraft.

Abstract: A method of joining a first component to a second component at respective connection surfaces, comprising, in order, applying a local surface treatment to the connection surface of at least one of the first and second components in order to locally alter the microstructure to a depth of between 60 ?m and 10 mm below the connection surface; and joining the first component to the second component using a welding process.

Abstract: A propulsion system for use with an aircraft includes a gas turbine engine, an electric power system, and at least one propulsor. The gas turbine engine includes a compressor, a combustor, and a turbine. The electric power system includes a generator coupled to the gas turbine engine to generate electrical energy, power electronics connected to the generator to receive the electrical energy from the generator, and a motor configured to produce rotational energy in response to receiving electric energy from the power electronics. The propulsor is configured to use rotational energy received from the motor of the electric power system to generate thrust for propelling the aircraft.

Abstract: A method (56) for fabricating an integral assembly (24) is disclosed. The method comprises providing (56) a first workpiece (26) having a first surface and a second workpiece (30) having a second surface (54), performing a first bonding process between the first surface of the first workpiece (26) and the second surface (54) of the second workpiece (30) the bulk material of the first workpiece having a friction weld property that makes it more difficult to weld than a friction weld property at the surface.

Abstract: A method for friction welding of inter alia coarse grain superalloy components, involving conditioning a shear zone of components to be welded by; a) pre-determining temperature profile for which the material of the shear zone of the components approaches viscoplasticity but does not undergo undesirable phase transformations, b) introducing friction at one or both surfaces of the components to be welded to provide a pre-defined quantum of energy sufficient to generate a peak temperature of the temperature profile at that surface whilst simultaneously applying pressure to the surfaces which is below a pressure which will cause upset at the surface, c) withdrawing the friction and/or pressure allowing the heat to disperse by conduction through the shear zone; d) after the temperature at the surface falls below peak temperature, repeating steps b) and c); and repeating step d) as necessary until the pre-determined temperature gradient is achieved throughout the shear zone.

Abstract: A method is provided of replacing a damaged blade of an integrally bladed rotor assembly including a disc and a plurality of blades extending outwardly from a rim of the disc. The method includes the steps of: removing the damaged blade to leave a blade repair stub projecting from the rim; locating sacrificial supports at the underside of the rim beneath the repair stub, the supports projecting axially beyond the trailing and leading edges of the rim; depositing metal around the trailing and leading edges of the repair stub, the deposited metal, supported by the sacrificial supports, projecting axially beyond the trailing and leading edges of the rim; attaching a replacement blade to the repair stub by linear friction welding; and removing excess deposited metal, upset metal from the linear friction welding, and the sacrificial supports.

Abstract: A method is provided of replacing a damaged blade of an integrally bladed rotor assembly including a disc and a plurality of blades extending outwardly from a rim of the disc. The method includes the steps of: removing the damaged blade to leave a blade repair stub projecting from the rim; locating sacrificial supports at the underside of the rim beneath the repair stub, the supports projecting axially beyond the trailing and leading edges of the rim; depositing metal around the trailing and leading edges of the repair stub, the deposited metal, supported by the sacrificial supports, projecting axially beyond the trailing and leading edges of the rim; attaching a replacement blade to the repair stub by linear friction welding; and removing excess deposited metal, upset metal from the linear friction welding, and the sacrificial supports.