Abstract: A gas turbine engine includes a fan assembly, a compressor assembly, a combustion chamber, a turbine assembly, a bypass duct conveying rearward a bypass airstream driven by the fan assembly when the gas turbine engine is in use, a fairing extending across at least a portion of the bypass duct downstream of the fan assembly, and a heat exchanger having an inlet fluidly connected to the compressor assembly and an outlet fluidly connected to a pneumatic actuator of the gas turbine engine. The fairing has a leading edge and a trailing edge. The heat exchanger is disposed adjacent the trailing edge of the fairing.

Abstract: An aircraft engine comprises a casing extending circumferentially around a central axis. A support flange is secured to the casing and extends circumferentially around the axis. The support flange has an inner and an outer flange face. A component is drivingly engaged by a shaft of the engine. The component has a connecting section extending around the central axis. The connecting section has a connecting face. The inner flange face is in abutment against the connecting face. A retaining ring extends circumferentially around the central axis. The retaining ring is in abutment against the outer flange face of the support flange. The retaining ring has a coefficient of thermal expansion, which is less than that of the support flange.

Abstract: Lubrication systems of an aircraft engine and associated methods are provided. The lubrication system includes a chamber having a fluid inlet for receiving lubricating fluid into the chamber, and a fluid outlet for draining the lubricating fluid from the chamber. The fluid outlet is disposed on a wall defining part of the chamber. A rotor is disposed inside the chamber and interacts with the lubricating fluid inside the chamber. The rotor is rotatable in a rotation direction about a rotation axis. A perforated baffle is disposed in the chamber for interacting with the lubricating fluid inside the chamber. The perforated baffle includes a base attached to the wall of the chamber. The base of the perforated baffle is disposed at an angular position preceding the fluid outlet relative to the rotation direction of the rotor.

Abstract: A method of priming a pump includes supplying lubricant, via a priming flow path, into an interface defined between a first part of a shaft of the pump and a second part of the shaft coaxially engaged with the first part of the shaft to define the pump, the first part of the shaft rotatable about a rotation axis relative to the second part of the shaft, and supplying lubricant into the interface via a lubrication flow path that is different from the priming flow path. A method of lubricating an aircraft motor of an aircraft engine, and a machine for an aircraft engine are also described.

Abstract: The auxiliary duct can branch radially outwardly from the bypass duct, have a proximal end fluidly connecting the bypass duct and a distal end, a valve can be activatable to selectively open and close the auxiliary passage, and a structure can protrude partially from the auxiliary duct into the auxiliary passage, the structure spaced apart from the proximal end, between the proximal end and the valve, the structure generating lesser pressure losses when flow in the auxiliary passage is directed towards the distal end than when the flow is directed towards the proximal end.

Abstract: Systems and methods for delivering a buffer fluid to a shaft seal of a gas turbine engine are provided. An exemplary system includes, a buffer fluid source, one or more first conduits providing fluid communication between the buffer fluid source and the shaft seal along a first route, and one or more second conduits providing fluid communication between the buffer fluid source and the shaft seal along a second route different from the first route. A heat exchanger is also disposed along the first route to facilitate heat transfer between buffer fluid in the one or more first conduits and a cooling fluid.

Abstract: Electric aircraft power plants and associated methods are provided. One power plant includes an emergency power unit (EPU) for providing electric power in the event of a malfunction of a battery pack of an electric aircraft to permit the electric aircraft to make an emergency maneuver. The EPU includes a rocket engine for generating a stream of exhaust fluid using a rocket propellant, a turbine operatively connected to extract energy from the stream of exhaust fluid generated by the rocket engine, and an electric generator operatively connected to be driven by the turbine and to supply electric power to an electric motor propelling the electric aircraft.

Abstract: Pressure regulators together with associated methods and systems are provided. An embodiment of a pressure regulator includes a chamber having an inlet port for receiving a fluid and an outlet port for delivering the fluid at a regulated pressure. The pressure regulator includes a diaphragm defining at least part of the chamber, and the diaphragm defining a first orifice therethrough. The pressure regulator includes a spring configured to interact with the diaphragm. The pressure regulator includes an interface operatively disposed between the spring and the diaphragm. The interface includes a contact surface for contacting the diaphragm, and the contact surface is convex toward the diaphragm. The interface defines a second orifice therethrough that is in fluid communication with the first orifice in the diaphragm. The first and second orifices define a relief port for venting the chamber to an ambient environment external to the chamber.

Abstract: A lubrication system for an aircraft engine includes an engine lubricant tank including at least a supply port hydraulically connectable to the aircraft engine, a lubricant makeup port, and an overfill port, an auxiliary lubricant tank, a lubricant makeup conduit hydraulically connecting the auxiliary lubricant tank to the lubricant makeup port. The lubricant makeup conduit includes a pump operable to move lubricant from the auxiliary lubricant tank to the lubricant makeup port, and an overfill conduit hydraulically connecting the overfill port to the auxiliary lubricant tank. A method of operating a lubrication system of an aircraft engine of an aircraft is also disclosed.

Abstract: An oil tank for a gas turbine engine is provided. The oil tank includes an oil cavity defined within structural walls of a nacelle of the gas turbine engine, the oil cavity having an oil inlet and an oil outlet. At least one of the structural walls has an interior side facing the oil cavity and an exterior side. The interior side includes a plurality of upstanding protrusions extending into the oil cavity and fully immersed in oil when the gas turbine engine is in use during steady state operation. The exterior side includes a plurality of fins extending therefrom and exposed to an ambient air stream during steady state operation of the gas turbine engine.

Abstract: The torque transfer assembly can include a sleeve having an elongated internal opening, a shaft having an elongated body extending in the internal opening of the sleeve, a first coupler at a first end of the elongated body coupled to a gas turbine engine rotor, and a second coupler at a second end of the elongated body coupled to a generator, the second coupler opposite the first coupler relative to a length of the elongated body, the shaft being made of a metal, and a bushing extending around the elongated body of the shaft, trapped between the shaft and the sleeve, the bushing made of plastic, the bushing having a coefficient of thermal expansion greater than a coefficient of thermal expansion of the sleeve.

Abstract: An aircraft pneumatic system including a pneumatic actuator arranged to operate at a pressure value at least equal to a pressure threshold, a line fluidly connected between a pneumatic source and the pneumatic actuator, and a venturi disposed upstream of the line and downstream of the pneumatic source. The venturi is configured to receive a source flow from the source at a mass flow rate, the mass flow rate being between a lower, nominal flow rate value and a higher, graded flow rate value. The venturi is sized such that when the mass flow rate is at the nominal flow rate value, a line pressure inside the line corresponds to a source pressure upstream of the venturi, and when the mass flow rate to the venturi is at the graded flow rate value, the line pressure is less than the source pressure.

Abstract: The auxiliary duct can branch radially outwardly from the bypass duct, have a proximal end fluidly connecting the bypass duct and a distal end, a valve can be activatable to selectively open and close the auxiliary passage, and a structure can protrude partially from the auxiliary duct into the auxiliary passage, the structure spaced apart from the proximal end, between the proximal end and the valve, the structure generating lesser pressure losses when flow in the auxiliary passage is directed towards the distal end than when the flow is directed towards the proximal end.

Abstract: An aircraft assist system described herein includes an aircraft coupling counterpart attached to a strut of a landing gear of an aircraft, and an assist vehicle. The assist vehicle includes a frame, ground-engaging wheels mounted to the frame, a power source for driving one or more of the ground-engaging wheels, and a vehicle coupling counterpart for engagement with the aircraft coupling counterpart. The aircraft coupling counterpart and the vehicle coupling counterpart define a swivel connection for transferring a propulsive force from the takeoff assist vehicle to the aircraft. The aircraft coupling counterpart is disengageable from the vehicle coupling counterpart by upward movement of the aircraft coupling counterpart relative to the vehicle coupling counterpart.

Abstract: The torque transfer assembly can include a sleeve having an elongated internal opening, a shaft having an elongated body extending in the internal opening of the sleeve, a first coupler at a first end of the elongated body coupled to a gas turbine engine rotor, and a second coupler at a second end of the elongated body coupled to a generator, the second coupler opposite the first coupler relative to a length of the elongated body, the shaft being made of a metal, and a bushing extending around the elongated body of the shaft, trapped between the shaft and the sleeve, the bushing made of plastic, the bushing having a coefficient of thermal expansion greater than a coefficient of thermal expansion of the sleeve.

Abstract: The heat exchanger includes an inner casing extending circumferentially around the central axis and securable to the shaft for concurrent rotation therewith, and an outer casing extending circumferentially around the central axis and secured to the inner casing, the outer casing located radially outwardly of the inner casing relative to the central axis. First conduits are secured to the outer casing and to the inner casing for rotation about the central axis, the first conduits located radially between the outer casing and the inner casing, and circumferentially distributed about the central axis. First passages are defined in the first conduits. Second passages are circumferentially interspaced between the first passages and are located radially between the inner casing and the outer casing. The second passages are in heat exchange relationship with the first passages.

Abstract: A fluid cooler for installation in a bypass duct of a turbofan gas turbine engine and associated methods are provided. The fluid cooler includes an inlet duct, a heat exchanger and an outlet duct. The inlet duct includes an inlet protruding into the bypass duct to receive a portion of the bypass air into the inlet duct. The heat exchanger is in fluid communication with the inlet duct. The heat exchanger facilitates heat transfer between a fluid and the portion of bypass air received into the inlet duct. The heat exchanger defines a general flow direction for the portion of bypass air that is different from the main flow direction of bypass air inside the bypass duct. The outlet duct conveys the portion of bypass air from the heat exchanger back to the bypass duct.

Abstract: The coupling can have a female member configured to rotate around an axis, defining an axial recess, and having a plurality of connections circumferentially arranged along a radially inner face; a male member extending inside the axial recess concentrically to the female member and having a plurality of connections circumferentially arranged along a radially outer face; and a plurality of circumferentially arranged links, each link having an inner end engaged with a corresponding one of the male member connections, and an outer end engaged with a corresponding female member connection, the links being slanted off the radial orientation, with the inner end being circumferentially offset from the outer end, the links subjected to compression when transmitting torque between the female member and male member.

Abstract: Systems and methods for delivering a buffer fluid to a shaft seal of a gas turbine engine are provided. An exemplary system includes, a buffer fluid source, one or more first conduits providing fluid communication between the buffer fluid source and the shaft seal along a first route, and one or more second conduits providing fluid communication between the buffer fluid source and the shaft seal along a second route different from the first route. A heat exchanger is also disposed along the first route to facilitate heat transfer between buffer fluid in the one or more first conduits and a cooling fluid.

Abstract: A duct for a gas turbine engine, the duct has a wall defining a flow passage for an airflow, the wall defining a baseline surface, the duct comprising an off-take port for drawing a portion of the airflow out of the duct, the off-take port including a projected portion projecting away from the baseline surface into the flow passage, a conduit opening defined within the projected portion for receiving the portion of the airflow, and an off-take conduit communicating with the conduit opening for directing the portion of the airflow away from the duct, the projected portion having a hump upstream of the conduit opening relative to a direction of the airflow and a scoop downstream of the opening relative to the direction of the airflow.