Aircraft electrically-assisted propulsion control system

A method of operating an aircraft propulsion system having an engine including a propulsive fan and an engine core, the engine core comprising a compressor, a combustor and a turbine, the propulsive fan configured to generate a mass flow of air that bypasses the engine core and propels an aircraft on which the engine is located;

• and an electrical energy store on board the aircraft, the method comprising:
• supplying fuel to the combustor to produce a flow of combustion products for driving the turbine and the compressor;
• monitoring conditions indicative of contrail formation;
• selectively altering a ratio of the mass flow of air by the propulsive fan to the flow of combustion products of the combustor;
• and
• concurrently assisting rotation of the compressor by the electrical energy store during the altering of said ratio.

A data carrier comprising machine-readable instructions for operation of an aircraft propulsion controller to:

• receive sensor readings for a plurality of engine operation variables;
• monitor conditions pertaining to adverse contrail formation by combustion products from an engine core combustor;
• output control instructions in response to a determination of adverse contrail formation to alter a ratio of a mass flow of air by a propulsive fan to a flow of combustion products of the engine core combustor, the propulsive fan included in an engine comprising the engine core combustor, the propulsive fan configured to generate the mass flow of air that bypasses an engine core and propels an aircraft on which the engine is located, the engine core including the engine core combustor;
• and concurrently output control instructions to selectively assist rotation of a compressor for the engine core by an electrical energy store.

An aircraft propulsion system comprising:

• an engine having a propulsive fan and an engine core, the engine core comprising a compressor, a combustor and a turbine driven by a flow of combustion products of the combustor, the propulsive fan configured to generate a mass flow of air, which bypasses the engine core and propels an aircraft on which the engine is located;
• an electrical energy store on board the aircraft;
• at least one electric motor arranged to drive the propulsive fan and the engine core compressor;
• and
• a controller arranged for control of the at least one electric motor to alter a ratio of the mass flow of air by the propulsive fan to the flow of combustion products of the combustor,
• wherein control of the at least one electric motor comprises selectively and concurrently driving both the propulsive fan and engine core compressor.