A gas turbine engine for an aircraft comprising an engine core and including a bypass channel which radially surrounds the engine core at least in part is described. A core shaft is operatively connected to an engine accessory gearbox, which is arranged between the engine core and the bypass channel, by means of a radial shaft of a drive train. An electric machine is provided which is designed to start the gas turbine engine during motor operation and to generate electrical energy during alternator operation. The electric machine is arranged coaxially with the core shaft and connected thereto for conjoint rotation. Alternatively, the electric machine can be arranged radially outside the bypass channel and can be operatively connected to the core shaft by means of the radial shaft, wherein a rotor of the electric machine is arranged coaxially with the radial shaft and connected thereto for conjoint rotation.

An auxiliary device system includes a motor generator, an auxiliary device motor, a converter configured to convert electric power generated by the motor generator, an inverter configured to drive the motor generator and the auxiliary device motor, a switch configured to be switched between a motor generator control state in which the inverter controls the motor generator and an auxiliary device motor control state in which the inverter controls the auxiliary device motor, and a controller configured to control the switch. When a condition in which a motor generator drive command is generated is satisfied, the controller sets the switch to the motor generator control state. When the condition is not satisfied, the controller sets the switch to the auxiliary device motor control state.

An auxiliary device system includes a motor generator, an auxiliary device motor, a converter configured to convert electric power generated by the motor generator, an inverter configured to drive the motor generator and the auxiliary device motor, a switch configured to be switched between a motor generator control state in which the inverter controls the motor generator and an auxiliary device motor control state in which the inverter controls the auxiliary device motor, and a controller configured to control the switch. When a condition in which a motor generator drive command is generated is satisfied, the controller sets the switch to the motor generator control state. When the condition is not satisfied, the controller sets the switch to the auxiliary device motor control state.

A geared turbofan engine with at least one compression stage and at least one turbine stage on a high speed shaft, the high speed shaft coupled through a speed reduction gear box to a low speed shaft with a fan and a starter/generator. The low speed shaft is collinear with the high speed shaft but does not rotate within the high speed shaft. The speed reduction gear box is positioned between and mechanically couples the high speed shaft and the low speed shaft, which allows the fan and the integrated starter/generator on the low speed shaft to operate at a lower speed than the high speed shaft.

An air starter for starting a turbine engine that includes a housing, a turbine member, a drive shaft, and at least one bearing assembly. The housing can define an interior where the turbine couples to the drive shaft that is rotatably supported by the least one bearing assembly. A lubricant passageway can provide lubrication to the at least one bearing assembly.

An air starter for starting a turbine engine that includes a housing, a turbine member, a drive shaft, and at least one bearing assembly. The housing can define an interior where the turbine couples to the drive shaft that is rotatably supported by the least one bearing assembly. A lubricant passageway can provide lubrication to the at least one bearing assembly.

An engine system for an aircraft includes a first gas turbine engine, a first core turning system, a second gas turbine engine, and a second core turning system. The engine system also includes a controller operable to shutdown the first gas turbine engine responsive to determining that the aircraft has landed and operate in the second gas turbine engine in a taxi mode while using the first core turning system to cool the first gas turbine engine. The controller is further operable to shutdown the second gas turbine engine and disable the first core turning system based on a power-down condition, restart the first gas turbine engine and use the second core turning system to cool the second gas turbine engine based on a restart condition, and complete cooling of the second gas turbine prior to restarting the second gas turbine engine.

An engine system for an aircraft includes a first gas turbine engine, a first core turning system, a second gas turbine engine, and a second core turning system. The engine system also includes a controller operable to shutdown the first gas turbine engine responsive to determining that the aircraft has landed and operate in the second gas turbine engine in a taxi mode while using the first core turning system to cool the first gas turbine engine. The controller is further operable to shutdown the second gas turbine engine and disable the first core turning system based on a power-down condition, restart the first gas turbine engine and use the second core turning system to cool the second gas turbine engine based on a restart condition, and complete cooling of the second gas turbine prior to restarting the second gas turbine engine.

There is described a method and system for in-flight start of an engine. The method comprises rotating a propeller; generating electrical power at an electric generator embedded inside a propeller hub from rotation of the propeller; transmitting the electrical power from the electric generator to an engine starter mounted on a core of the engine via an electric power link; and driving the engine with the engine starter to a sufficient speed while providing fuel to a combustor to light the engine to achieve self-sustaining operation of the engine.

There is described a method and system for in-flight start of an engine. The method comprises rotating a propeller; generating electrical power at an electric generator embedded inside a propeller hub from rotation of the propeller; transmitting the electrical power from the electric generator to an engine starter mounted on a core of the engine via an electric power link; and driving the engine with the engine starter to a sufficient speed while providing fuel to a combustor to light the engine to achieve self-sustaining operation of the engine.