Abstract: An anti-icing system for a gas turbine engine comprises a closed circuit containing a phase-change fluid, at least one heating component for boiling the phase-change fluid, the anti-icing system configured so that the phase-change fluid partially vaporizes to a vapour state when boiled by the at least one heating component. The closed circuit has an anti-icing cavity adapted to be in heat exchange with an anti-icing surface of the gas turbine engine for the phase-change fluid to release heat to the anti-icing surface and condense. A feed conduit(s) has an outlet end in fluid communication with the anti-icing cavity to feed the phase-change fluid in vapour state from heating by the at least one heating component to the anti-icing cavity, and at least one return conduit having an outlet end in fluid communication with the anti-icing cavity to direct condensed phase-change fluid from the anti-icing cavity to the at least one heating component.

Abstract: A method of manufacturing a bearing support structure of a gas turbine engine, includes: obtaining a bearing support and a casing assembly, the casing assembly having first and second casings extending around a central axis and connected together via struts, the bearing support securable to the first casing at attachment points; selecting a distance between the attachment points of the bearing support and the struts as a function of a required stiffness of the bearing support structure; and adjusting a position of the bearing support relative to the casing assembly until the attachment points are distanced from the struts by the selected distance and joining the bearing support to the casing assembly at the attachment points.

Abstract: The gas turbine engine can have an accessory gearbox having a sump; an oil tank; a user interface configured to generate a signal upon receiving a user input indicative of an oil measurement reading; and a pump configured to pump oil from the sump to the oil tank upon receiving the user input.

Abstract: The aircraft engine can have an air-oil separator having an air-oil mixture inlet, an oil outlet, an air outlet, and a pressure relief path provided fluidly in parallel with the air-oil separator, between the air-oil mixture inlet and the air outlet, the pressure relief path can have a pressure relief valve for evacuating air-oil mixture to the exhaust duct in the event of excess pressure in the auxiliary gearbox.

Abstract: A method of manufacturing a bearing support structure of a gas turbine engine, includes: obtaining a bearing support and a casing assembly, the casing assembly having first and second casings extending around a central axis and connected together via struts, the bearing support securable to the first casing at attachment points; selecting a distance between the attachment points of the bearing support and the struts as a function of a required stiffness of the bearing support structure; and adjusting a position of the bearing support relative to the casing assembly until the attachment points are distanced from the struts by the selected distance and joining the bearing support to the casing assembly at the attachment points.

Abstract: A system for controlling gas turbine engine rotor blades tip clearance is described. A rotor is mounted to an engine shaft, supported by a thrust bearing, for rotation within a gas path shroud circumscribing blades of the rotor, the gas path shroud having a non-cylindrical shape in the vicinity of the rotor blades. A rotary actuator is associated with the thrust bearing and configured for axial translation of the thrust bearing, to thereby axially translate the engine shaft and the rotor blades relative to the gas path shroud. This translation is configured to vary the blade tip clearance of the rotor.

Abstract: The aircraft engine can have an air-oil separator having an air-oil mixture inlet, an oil outlet, an air outlet, and a pressure relief path provided fluidly in parallel with the air-oil separator, between the air-oil mixture inlet and the air outlet, the pressure relief path can have a pressure relief valve for evacuating air-oil mixture to the exhaust duct in the event of excess pressure in the auxiliary gearbox.

Abstract: The gas turbine engine can have an accessory gearbox having a sump; an oil tank; a user interface configured to generate a signal upon receiving a user input indicative of an oil measurement reading; and a pump configured to pump oil from the sump to the oil tank upon receiving the user input.

Abstract: A system for controlling gas turbine engine rotor blades tip clearance is described. A rotor is mounted to an engine shaft, supported by a thrust bearing, for rotation within a gas path shroud circumscribing blades of the rotor, the gas path shroud having a non-cylindrical shape in the vicinity of the rotor blades. A rotary actuator is associated with the thrust bearing and configured for axial translation of the thrust bearing, to thereby axially translate the engine shaft and the rotor blades relative to the gas path shroud. This translation is configured to vary the blade tip clearance of the rotor.

Abstract: An anti-icing system for a gas turbine engine comprises a closed circuit containing a phase-change fluid, at least one heating component for boiling the phase-change fluid, the anti-icing system configured so that the phase-change fluid partially vaporizes to a vapour state when boiled by the at least one heating component. The closed circuit has an anti-icing cavity adapted to be in heat exchange with an anti-icing surface of the gas turbine engine for the phase-change fluid to release heat to the anti-icing surface and condense. A feed conduit(s) has an outlet end in fluid communication with the anti-icing cavity to feed the phase-change fluid in vapour state from heating by the at least one heating component to the anti-icing cavity, and at least one return conduit having an outlet end in fluid communication with the anti-icing cavity to direct condensed phase-change fluid from the anti-icing cavity to the at least one heating component.

Abstract: A variable stator guide vane system for a gas turbine engine comprises a set of vanes circumferentially distributed around a central axis and rotatably mounted for rotation about respective spanwise axes. A ring gear is rotatably mounted about the central axis. Pinion gears are operatively coupled to respective ones of the vanes and in driving engagement with the ring gear. Biasing members individually bias the pinion gears in meshing engagement with the ring gear.

Abstract: A controlled gap seal device is adapted to surround a shaft with an annular seal element. A ring is positioned on an outer surface of the seal element, the ring adapted to modify a diametrical dimension of the seal element by thermally expanding/contracting as a function of temperature variations. A housing assembly has an interior enclosing the seal element and the ring, with the seal configured to be generally stationary in the interior. The housing assembly has an air inlet and air outlet in fluid communication with a surrounding environment for directing a flow of gas from the surrounding environment onto the ring to controllably cool and shrink the ring. A method for modifying a diameter of a controlled gap seal relative to the shaft is also provided.

Abstract: An air-to-air cooler has a heat exchanger integrated to a housing. A first passage extends through the housing for directing a flow of cooling air through the heat exchanger. A second passage extends through the housing for directing a flow of hot air to be cooled through the heat exchanger. The first passage has a cooling air outlet tube disposed downstream of the heat exchanger. The cooling air outlet tube extends across the second passage between the heat exchanger and a hot air inlet of the second passage. The hot air inlet is disposed to cause incoming hot air to flow over the cooling air outlet tube upstream of the heat exchanger. An ejector drives the flow of cooling air through the first passage of the air-to-air cooler. A portion of the hot air flow may be used to drive the ejector.

Abstract: A variable stator guide vane system for a gas turbine engine comprises a set of vanes circumferentially distributed around a central axis and rotatably mounted for rotation about respective spanwise axes. A ring gear is rotatably mounted about the central axis. Pinion gears are operatively coupled to respective ones of the vanes and in driving engagement with the ring gear. Biasing members individually bias the pinion gears in meshing engagement with the ring gear.

Abstract: A method of assembling a starter/generator in a gas-turbine engine, including coupling a rotor and a stator of the starter/generator such that the rotor is rotatable with respect to the stator to drive the rotor when the starter/generator is electrically powered and to produce electrical power when the rotor is rotated, securing the stator to a bearing support, coupling the starter/generator to a low pressure shaft of the engine by installing the bearing support over a bearing assembly secured to an end of the low pressure shaft, inserting the low pressure shaft through a high pressure shaft of the engine with the end of the low pressure shaft protruding therefrom and positioning the starter/generator in proximity of an end of the high pressure shaft, and drivingly engaging the rotor to the high pressure shaft.

Abstract: An air-to-air cooler has a heat exchanger integrated to a housing. A first passage extends through the housing for directing a flow of cooling air through the heat exchanger. A second passage extends through the housing for directing a flow of hot air to be cooled through the heat exchanger. The first passage has a cooling air outlet tube disposed downstream of the heat exchanger. The cooling air outlet tube extends across the second passage between the heat exchanger and a hot air inlet of the second passage. The hot air inlet is disposed to cause incoming hot air to flow over the cooling air outlet tube upstream of the heat exchanger. An ejector drives the flow of cooling air through the first passage of the air-to-air cooler. A portion of the hot air flow may be used to drive the ejector.

Abstract: An air-to-air cooler has a heat exchanger integrated to a housing. A first passage extends through the housing for directing a flow of cooling air through the heat exchanger. A second passage extends through the housing for directing a flow of hot air to be cooled through the heat exchanger. The first passage has a cooling air outlet tube disposed downstream of the heat exchanger. The cooling air outlet tube extends across the second passage between the heat exchanger and a hot air inlet of the second passage. The hot air inlet is disposed to cause incoming hot air to flow over the cooling air outlet tube upstream of the heat exchanger. An ejector drives the flow of cooling air through the first passage of the air-to-air cooler. A portion of the hot air flow may be used to drive the ejector.

Abstract: A controlled gap seal device is adapted to surround a shaft with an annular seal element. A ring is positioned on an outer surface of the seal element, the ring adapted to modify a diametrical dimension of the seal element by thermally expanding/contracting as a function of temperature variations. A housing assembly has an interior enclosing the seal element and the ring, with the seal configured to be generally stationary in the interior. The housing assembly has an air inlet and air outlet in fluid communication with a surrounding environment for directing a flow of gas from the surrounding environment onto the ring to controllably cool and shrink the ring. A method for modifying a diameter of a controlled gap seal relative to the shaft is also provided.

Abstract: A gas turbine engine with a transmission having a variable ratio is discussed. A first gear train is in driving engagement with the low pressure spool and has a first output gear. A second gear train is in driving engagement with the high pressure spool and has a second output gear spaced apart from the first output gear. A third gear train defines a driving engagement between the low pressure spool and the low pressure compressor rotor with a variable transmission ratio. A fourth gear train is in driving engagement with the first and second output gears, and in driving engagement with the third gear train to determine the transmission ratio. A method of adjusting a speed of a low pressure compressor rotor of a gas turbine engine is also discussed.

Abstract: A controlled gap seal device is adapted to surround a shaft with an annular seal element. A ring is positioned on an outer surface of the seal element, the ring adapted to modify a diametrical dimension of the seal element by thermally expanding/contracting as a function of temperature variations. A housing assembly has an interior enclosing the seal element and the ring, with the seal configured to be generally stationary in the interior. The housing assembly has an air inlet and air outlet in fluid communication with a surrounding environment for directing a flow of gas from the surrounding environment onto the ring to controllably cool and shrink the ring. A method for modifying a diameter of a controlled gap seal relative to the shaft is also provided.