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.

With regard to a load running system that comprises a plurality of compressors that compress a fuel gas and supply the compressed fuel gas to a load apparatus, this compressor control device comprises: a feedforward control signal generation unit that, on the basis of a value that is found by dividing the total load of the load apparatus by the number of running compressors, generates a first control signal that is for controlling the amount of fuel gas supplied by the compressors; and a control unit that, on the basis of the first control signal, controls the amount of fuel gas supplied by the compressors.

An engine system comprises first and second electrical generators coupled to lower and higher pressure (LP, HP) shafts respectively of a gas turbine engine. A controller is arranged to receive a signal corresponding to a total electrical power demand P.sub.1 and to output control signals to the electrical generators in response thereto such that the first and second electrical generators output electrical powers (1y)P.sub.1 and yP.sub.1 respectively when P.sub.1P.sub.m1, where 0.5<y1 and P.sub.m1 is the maximum electrical output power of the first electrical generator. By satisfying the demand P.sub.1 mostly by extraction of electrical power from the first electrical generator when possible, the additional mechanical stress on the gas turbine engine resulting from electrical power extraction is reduced compared to the case where 50% or more of the demand P.sub.1 is satisfied by the second electrical generator.

The turboshaft engine for a rotorcraft includes a low pressure spool having a low pressure compressor and a low pressure turbine section, and a high pressure spool having a high pressure compressor and a high pressure turbine section. The spools are independently rotatable relative to one another. The low pressure compressor section includes a mixed flow rotor. A set of variable guide vanes (VGVs) are disposed upstream of each of the low pressure and high pressure compressors, the VGVs being configured to be independently operable relative to one another.

A method of operating a multi-engine system of a rotorcraft includes, during a cruise flight segment of the rotorcraft, controlling a first engine to provide sufficient power and/or rotor speed demands of the cruise flight segment; and controlling a second engine to by providing a fuel flow to the second engine that is between 70% and 99.5% less than a fuel flow provided to the first engine. A turboshaft engine for a multi-engine system configured to drive a common load is also described.

An electrical power system architecture and method for allocating power includes a power distribution bus configured to receive power generated by a first engine having a first generator and a second generator, a first set of electrical buses connected with the power distribution bus and associated with the first engine, and a second set of electrical buses configured to selectively connect with the power distribution bus.

An aircraft propulsion system is disclosed and includes a first gas turbine engine including a first input shaft driving a first gear system, a first fan driven by the first gear system, a first generator supported on the first input shaft and a fan drive electric motor providing a drive input to the first fan, a second gas turbine engine including a second input shaft driving a second gear system, a second fan driven by the second gear system, a second generator supported on the second input shaft and a second fan drive electric motor providing a drive input to the second fan and a controller controlling power output from each of the first and second generators and directing the power output between each of the first and second fan drive electric motors.

A propulsion system for an aircraft includes at least two gas turbine engines and at least one auxiliary propulsion fan. The at least one auxiliary propulsion fan is configured to selectively receive a motive force from either or both of the at least two gas turbine engines through at least one shaft operatively coupled to the at least one auxiliary propulsion fan.

A hybrid-electric gas turbine engine and method of operating includes independently controlling a first electric machine providing torque to a first shaft to maintain a desired clearance between a first set of blades rotatably coupled to the first shaft, and a casing.

A method of operating a multi-engine system of a rotorcraft includes, during a cruise flight segment of the rotorcraft, controlling a first engine to provide sufficient power and/or rotor speed demands of the cruise flight segment; and controlling a second engine to by providing a fuel flow to the second engine that is between 70% and 99.5% less than a fuel flow provided to the first engine. A turboshaft engine for a multi-engine system configured to drive a common load is also described.