Abstract: 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.

Abstract: The present disclosure provides methods and systems for operating a rotorcraft comprising a plurality of engines configured to provide motive power to the rotorcraft. The rotorcraft is operated in a first flight regime. A target output power range for at least one of the plurality of engines is determined, the target output power range associated with operating the rotorcraft in a second flight regime different from the first flight regime in which at least one first engine of the plurality of engines is operated in an active mode to provide motive power to the rotorcraft and at least one second engine of the plurality of engines is operated in a standby mode to provide substantially no motive power to the rotorcraft. A graphical representation of the target output power range for the second flight regime is produced via a flight display in a cockpit of the rotorcraft.

Abstract: Methods and systems for operating a rotorcraft comprising a plurality of engines are provided. A request to enter into an asymmetric operating regime (AOR), in which at least one active engine of the plurality of engines is operated in an active mode to provide motive power to the rotorcraft and at least one standby engine of the plurality of engines is operated in a standby mode to provide substantially no motive power, is obtained. Engine usage data for the plurality of engines, including at least one first engine and at least one second engine, is determined. Based on the engine usage data, one of the at least one first and second engines is operated as the at least one active engine for the AOR, and the other one of the at least one first and second engines is operated as the at least one standby engine for the AOR.

Abstract: An aircraft engine has a high pressure spool including a high pressure turbine drivingly connected to a high pressure compressor. A low pressure spool including a low pressure compressor is fluidly connected to the high pressure compressor. A low pressure turbine is drivingly connected to the low pressure compressor to drive the low pressure compressor. A load is drivingly connected to the low pressure turbine, the load consisting of one of a propeller and a helicopter rotor. A method of creating classes of an aircraft engine from an engine platform is disclosed.

Abstract: A method of providing an engine family includes providing a first engine having a low pressure turbine driving a low pressure compressor at a first speed ratio, and a high pressure turbine driving a high pressure compressor. The method includes providing a second engine by changing the first speed ratio of the first engine to a second speed ratio.

Abstract: A gas turbine engine has a first spool having a low pressure compressor section in fluid communication with an air inlet, the low pressure compressor section including a first plurality of variable guide vanes therein, and a low pressure turbine section drivingly engaged to the low pressure compressor section. A second spool has a high pressure compressor section in fluid communication with the low pressure compressor section to receive pressurized air therefrom, the high pressure compressor section including a second plurality of variable guide vanes at an entry thereof, and a high pressure turbine section drivingly engaged to the high pressure compressor section, the high pressure turbine section disposed upstream of the low pressure turbine section and in fluid communication therewith. An output drive shaft drivingly engages the low pressure turbine section and is adapted to drivingly engage a rotatable load of the gas turbine engine.

Abstract: A gas turbine engine has a first spool having a low pressure compressor section in fluid communication with an air inlet, the low pressure compressor section including a first plurality of variable guide vanes therein, and a low pressure turbine section drivingly engaged to the low pressure compressor section. A second spool has a high pressure compressor section in fluid communication with the low pressure compressor section to receive pressurized air therefrom, the high pressure compressor section including a second plurality of variable guide vanes at an entry thereof, and a high pressure turbine section drivingly engaged to the high pressure compressor section, the high pressure turbine section disposed upstream of the low pressure turbine section and in fluid communication therewith. An output drive shaft drivingly engages the low pressure turbine section and is adapted to drivingly engage a rotatable load of the gas turbine engine.

Abstract: The present disclosure provides methods and systems for operating a rotorcraft comprising a plurality of engines configured to provide motive power to the rotorcraft. The rotorcraft is operated in a first flight regime. A target output power range for at least one of the plurality of engines is determined, the target output power range associated with operating the rotorcraft in a second flight regime different from the first flight regime in which at least one first engine of the plurality of engines is operated in an active mode to provide motive power to the rotorcraft and at least one second engine of the plurality of engines is operated in a standby mode to provide substantially no motive power to the rotorcraft. A graphical representation of the target output power range for the second flight regime is produced via a flight display in a cockpit of the rotorcraft.

Abstract: Methods and systems for operating a rotorcraft comprising a plurality of engines are provided. A request to enter into an asymmetric operating regime (AOR), in which at least one active engine of the plurality of engines is operated in an active mode to provide motive power to the rotorcraft and at least one standby engine of the plurality of engines is operated in a standby mode to provide substantially no motive power, is obtained. Engine usage data for the plurality of engines, including at least one first engine and at least one second engine, is determined. Based on the engine usage data, one of the at least one first and second engines is operated as the at least one active engine for the AOR, and the other one of the at least one first and second engines is operated as the at least one standby engine for the AOR.

Abstract: A method of providing an engine family includes providing a first engine having a low pressure turbine driving a low pressure compressor at a first speed ratio, and a high pressure turbine driving a high pressure compressor. The method includes providing a second engine by changing the first speed ratio of the first engine to a second speed ratio.

Abstract: An aircraft engine has a high pressure spool including a high pressure turbine drivingly connected to a high pressure compressor. A low pressure spool including a low pressure compressor is fluidly connected to the high pressure compressor. A low pressure turbine is drivingly connected to the low pressure compressor to drive the low pressure compressor. A load is drivingly connected to the low pressure turbine, the load consisting of one of a propeller and a helicopter rotor. A method of creating classes of an aircraft engine from an engine platform is disclosed.

Abstract: 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.

Abstract: An active tip clearance control (ATCC) apparatus of an aircraft gas turbine engine is situated within a pressurized core case of the engine. First and second portions of bypass air flow passing through the respective compressed core compartment and the ATCC apparatus, are isolated from one another in order to improve both the ATCC performance and bypass air duct performance.

Abstract: An active tip clearance control (ATCC) apparatus of an aircraft gas turbine engine is situated within a pressurized core case of the engine. First and second portions of bypass air flow passing through the respective compressed core compartment and the ATCC apparatus, are isolated from one another in order to improve both the ATCC performance and bypass air duct performance.

Abstract: A turbine exhaust thin strut includes an airfoil section having a profile substantially in accordance with at least an intermediate portion of the Cartesian coordinate values of X, Y and Z set forth in Table 2. The X and Y values are distances, which when smoothly connected by an appropriate continuing curve, define airfoil profile sections at each distance Z. The profile sections at each distance Z are joined smoothly to one another to form a complete airfoil shape.

Abstract: A turbine exhaust thin strut includes an airfoil section having a profile substantially in accordance with at least an intermediate portion of the Cartesian coordinate values of X, Y and Z set forth in Table 2. The X and Y values are distances, which when smoothly connected by an appropriate continuing curve, define airfoil profile sections at each distance Z. The profile sections at each distance Z are joined smoothly to one another to form a complete airfoil shape.