Abstract: A cabin blower for an aircraft, the system comprising: a cabin blower compressor; an electric machine; and a controller configured to control the cabin blower system so that: in a cabin blower mode of operation, the cabin blower compressor is driven by power extracted from one or more spools of a gas turbine engine of the aircraft and provides a flow of air to a cabin of the aircraft. The controller may be further configured to control the system so that: in a rotor bow mitigation mode of operation, the cabin blower compressor is driven by the electric machine using electrical power from an electrical power source and provides a flow of air through a core of the gas turbine engine to remove heat from the core. A method of operating a cabin blower system of an aircraft is also provided.

Abstract: An aircraft propulsion system comprises a propulsor an electric motor coupled to the propulsor. The electric motor comprises a surface mounted permanent magnet electric machine comprising a rotor mounted radially inward of a stator. A Motor Diameter Ratio (MDR) is defined as an inner diameter (Dstator,in) of the motor stator in metres divided by an outer diameter (Dstator,out) of the motor stator in metres. The MDR of the electric motor stator is within 10% of the value given by the equation: MDR = 0.83 × ( Torq ? u ? e L a ? c ? t ? i ? v ? e × 1 U fan , tip ) 0 . 0 ? 8 where: T is the maximum torque rating of the electric motor in kilonewton metres; Lactive is the active length of the motor stator in metres; and Utip is the tip speed of the propulsor at the maximum rated torque of the electric motor in metres per second. In the described embodiments, the MDR is less than 1.

Abstract: A cabin blower for an aircraft, the system comprising: a cabin blower compressor; an electric machine; and a controller configured to control the cabin blower system so that: in a cabin blower mode of operation, the cabin blower compressor is driven by power extracted from one or more spools of a gas turbine engine of the aircraft and provides a flow of air to a cabin of the aircraft. The controller may be further configured to control the system so that: in a rotor bow mitigation mode of operation, the cabin blower compressor is driven by the electric machine using electrical power from an electrical power source and provides a flow of air through a core of the gas turbine engine to remove heat from the core. A method of operating a cabin blower system of an aircraft is also provided.