Abstract: A gas turbine engine has a first spool having a low pressure compressor section disposed forward of an air inlet along a direction of travel of the engine, and a low pressure turbine section disposed forward of the low pressure compressor section and drivingly engaged thereto. A second spool has a high pressure compressor section disposed forward of the low pressure compressor section, and a high pressure turbine section disposed forward of the high pressure compressor section and drivingly engaged thereto. The high pressure turbine section is disposed aft of the low pressure turbine section. An output drive shaft drivingly engages the low pressure turbine section and extends forwardly therefrom to drive a rotatable load. A method of operating a gas turbine engine is also discussed.

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 disposed forward of an air inlet along a direction of travel of the engine, and a low pressure turbine section disposed forward of the low pressure compressor section and drivingly engaged thereto. A second spool has a high pressure compressor section disposed forward of the low pressure compressor section, and a high pressure turbine section disposed forward of the high pressure compressor section and drivingly engaged thereto. The high pressure turbine section is disposed aft of the low pressure turbine section. An output drive shaft drivingly engages the low pressure turbine section and extends forwardly therefrom to drive a rotatable load. A method of operating a gas turbine engine is also discussed.

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 multi-spool gas turbine engine comprises a low pressure (LP) spool and a high pressure (HP) spool independently rotatable about a central axis extending through an accessory gear box (AGB). The LP spool has an LP compressor, which is axially positioned between the HP compressor of the HP spool and the AGB. A tower shaft drivingly connects the HP spool to the AGB.

Abstract: A turboprop gas turbine engine mountable to an aircraft has an engine core and a gearbox driving a propeller, the engine core and the gearbox being enclosed within a nacelle. The propeller is located rearward of the gearbox and the engine core relative to a direction of travel of the aircraft. An air intake is disposed within the nacelle and formed to direct ambient air into the engine core. The air intake includes an air inlet duct, having a forward-facing intake inlet receiving the ambient air, with an upstream section and a downstream section. The upstream section is in fluid communication with the intake inlet and extends downstream from the intake inlet. The downstream section fluidly connects to and directs air from the upstream section into the engine air inlet. A second air outlet duct is located within the nacelle and directs air into an air-cooled-oil-cooler (ACOC).

Abstract: A system and method for measuring average temperature of gas in an axial cross-section of a gas turbine engine gas path, involving diverting gas samples from different positions in the axial cross-section to a gas mixing chamber and measuring a temperature of the resulting mixed gas.

Abstract: A gas turbine engine has an in-line mounted accessory gear box (AGB) and an accessory drivingly connected to the AGB, the accessory being oriented transversally to the engine centerline.

Abstract: An exhaust mixer for a gas turbine engine includes an annular wall having upstream end adapted to be fastened to an engine case and a downstream end forming a plurality of inner and outer mixer lobes. A support member interconnects at least a number of the inner lobes, and includes a circumferentially extending stiffener ring located radially inwardly from the inner lobes and a series of circumferentially spaced apart mixer struts radially extending from the inner lobes to the stiffener ring. The mixer struts have a radial length at least equal to a width of a main gas path defined between the inner lobes and the exhaust cone such that the mixer struts extend entirely through the main gas path. The stiffener ring being fixed solely to the mixer struts such as to float with respect to the exhaust cone and permit relative movement therebetween.

Abstract: A multi-spool gas turbine engine comprises a low pressure (LP) spool and a high pressure (HP) spool independently rotatable about a central axis extending through an accessory gear box (AGB). The LP spool has an LP compressor, which is axially positioned between the HP compressor of the HP spool and the AGB. A tower shaft drivingly connects the HP spool to the AGB.

Abstract: The turbine exhaust structure for a gas turbine engine includes a turbine exhaust duct and a bearing housing. The turbine exhaust duct includes annular inner and outer case portions radially spaced apart to define an annular gas path therebetween and a plurality of struts extending between and structurally interconnecting the inner and outer case portions. The struts are circumferentially spaced apart about within the annular gas path. The bearing housing is disposed within the inner case portion of the turbine exhaust duct. A plurality of structural ribs extend between the bearing housing and the inner annular case portion. The structural ribs are circumferentially spaced from one another and are circumferentially offset from the struts.

Abstract: A method of operating a twin engine helicopter power plant, the power plant comprising: two turboshaft engines each having an engine shaft with a turbine at a distal end and a one-way clutch at a proximal end; a gear box having an input driven by the one way clutch of each engine and an output driving a helicopter rotor; a bypass clutch disposed between the proximal end of each engine shaft and the input of the gear box; and power plant management system controls for activating the bypass clutch; the method comprising: detecting when a rotary speed of an associated engine shaft is less than a rotary speed of the gear box input; activating the bypass clutch to drive the associated engine shaft using the rotation of the gear box input; and starting an associated engine by injecting fuel when the bypass clutch is activated.

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 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.

Abstract: A mixer of a bypass turbine aeroengine according to one embodiment, includes circumferential inner and outer flow surfaces in a wavy configuration to form a plurality of lobes of the mixer. The mixer has an upstream end portion of sheet metal with a first thickness and a downstream end portion of sheet metal with a second thickness less than the first thickness.

Abstract: A multi-spool gas turbine engine comprises a low pressure (LP) spool and a high pressure (HP) spool independently rotatable about a central axis extending through an accessory gear box (AGB). The LP spool has an LP compressor, which is axially positioned between the HP compressor of the HP spool and the AGB. A tower shaft drivingly connects the HP spool to the AGB.

Abstract: A method of manufacturing a turbine shroud segment for a gas turbine engine comprises: metal injection molding (MIM) a shroud segment body with a groove defined in a first lateral side thereof and with a flow restrictor projecting integrally from an opposite second lateral side thereof. The groove is oversized relative to the flow restrictor to provide for a clearance fit between the flow restrictor and the groove of adjacent turbine shroud segments when assembled together in a ring formation. The shroud segment body with the integrated flow restrictor are then subjected to debinding and sintering operations.

Abstract: A gas turbine shaft assembly comprises first and second axially mating shafts. The first shaft has a circumferential array of splines configured to mesh with a corresponding circumferential array of splines on the second shaft. The first shaft defines at least one axially extending slot aligned with one of the splines on the first shaft. The second shaft has at least one radial projection aligned with one of the splines on the second shaft. The engagement of the radial projection with the slot provides angular correspondence between the splines of the first and the second shafts prior to axial engagement of the splines.

Abstract: A mixer of a bypass turbine aeroengine according to one embodiment, includes circumferential inner and outer flow surfaces in a wavy configuration to form a plurality of lobes of the mixer. The mixer has an upstream end portion of sheet metal with a first thickness and a downstream end portion of sheet metal with a second thickness less than the first thickness.

Abstract: A mixer of a bypass turbine aeroengine according to one embodiment, includes circumferential inner and outer flow surfaces in a wavy configuration to form a plurality of lobes of the mixer. The mixer has an upstream end portion of sheet metal with a first thickness and a downstream end portion of sheet metal with a second thickness less than the first thickness.