Abstract: The nacelle can have an inlet portion having a duct wall and an outer skin, the duct wall being annular around an axis and having a surface forming a radially-outer delimitation to a gas path upstream of a fan area, the duct wall extending from a rounded inlet edge of the nacelle to the fan area, a cavity located inside the inlet portion, a compressed air inlet leading into the cavity, and an outlet fluidly connecting the cavity to the gas path, the outlet having a plurality of apertures disposed circumferentially around the duct wall, the apertures sloping circumferentially.

Abstract: Methods and tools for facilitating the installation and/or removal of a rotor on a shaft of a gas turbine engine are provided. The tool includes a stabilizer attachable to the shaft and including a first guide counterpart. The tool also includes a holder attachable to the rotor and including a second guide counterpart for engagement with the first guide counterpart of the stabilizer. Engagement of the first and second guide counterparts guides movement of the holder relative to the stabilizer along a guide axis and prevents movement of the holder relative to the stabilizer transverse to the guide axis.

Abstract: A fuel system can include a first fuel circuit, a second fuel circuit, and an inert gas purge system operatively connected to both the first fuel circuit and the second fuel circuit to purge at least a portion of either or both of the first and/or second fuel circuit. The first fuel can be a liquid fuel and the second fuel can be a gaseous fuel. The first fuel circuit can include a first fuel manifold configured to fluidly communicate a first fuel supply with at least one dual fuel nozzles downstream of the first fuel manifold.

Abstract: Methods and systems for filtering pressurized air used to control a compressor bleed valve of a gas turbine engine are provided. One method comprises receiving the pressurized air in a conduit via an inlet of the conduit, releasing a first portion of the pressurized air out of the conduit via an outlet of the conduit, releasing a second portion of the pressurized air from the conduit via a port disposed between the inlet and the outlet of the conduit, directing the second portion of the pressurized air from the port to a filter along an upward flow path, filtering the second portion of the pressurized air using the filter, and directing the second portion of the pressurized air from the filter toward the compressor bleed valve.

Abstract: A formation method is provided. During this formation method, a metallic substrate is provided. A coating is deposited onto the metallic substrate using a suspension plasma spray process. The coating is formed from or otherwise includes copper oxide.

Abstract: A rotor for an aircraft engine, has: a hub extending circumferentially about a central axis, the hub having a bore, a gaspath-facing surface located radially outwardly of the bore relative to the central axis, a first face extending from the bore to the gaspath-facing surface, and a second face opposite the first face and extending from the bore to the gaspath-facing surface; blades circumferentially distributed about the central axis, the blades protruding away from the gaspath-facing surface of the hub; and a crack mitigator located on the first face, the crack mitigator extending circumferentially relative to the central axis, the crack mitigator extending axially from a baseline surface of the first face.

Abstract: A method of controlling a hybrid-electric aircraft powerplant includes running a first control loop for command of a thermal engine based on error between total response commanded for a hybrid-electric powerplant and total response from the hybrid-electric powerplant. A second control loop runs in parallel with the first control loop for commanding the thermal engine based on error between maximum thermal engine output and total response commanded. A third control loop runs in parallel with the first and second control loops for commanding engine/propeller speed, wherein the third control loop outputs a speed control enable or disable status. A fourth control loop runs in parallel with the first, second, and third control loops for commanding the electric motor with non-zero demand when the second control loop is above control to add response from the electric motor to response from the thermal engine to achieve the response commanded.

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: A control system for a hybrid electric powerplant of an aircraft can include a throttle controller configured to receive one or more power settings and to output a heat engine setting and an electric motor setting, a heat engine controller operatively connected to the throttle controller. The heat engine controller can be configured to receive the heat engine setting and to control a heat engine system as a function of the heat engine setting to control torque output by a heat engine. The system can include a heat engine protection module that is part of or connected to the heat engine controller and configured to provide one or more protection commands to directly control one or more heat engine protection systems. The system can include an electric motor controller operatively connected to the throttle controller.

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: Lubricant pump systems and associated methods for aircraft engines are provided. The method includes receiving an input torque, dividing the input torque between a first load path receiving a first portion of the input torque, and a second load path receiving a second portion of the input torque. A first lubricant pump of the aircraft engine is driven via the first load path using the first portion of the input torque. A second lubricant pump of the aircraft engine is driven via the second load path using the second portion of the input torque. When a malfunction of the second lubricant pump occurs, the method includes ceasing to drive the first lubricant pump and the second lubricant pump using the input torque.

Abstract: There is described a system for manufacturing a part. The system generally has a receiving area receiving said part, a first reference gauge and a second reference gauge which are subjected to common environmental conditions, said first reference gauge having a first nominal dimension and said second reference gauge having a second nominal dimension different from said first nominal dimension; a measurement device measuring dimensions of said first and second reference gauges, and measuring dimensions of said part; and a controller communicatively coupled to said measurement device, said controller determining a calibration curve by performing a mathematical fit based on said first and second nominal dimensions and said measured dimensions of said first and second reference gauges; and constructing a machine-readable dataset representative of said part, including modifying said measured dimensions of said part based on said calibration curve.

Abstract: An apparatus for a gas turbine engine includes a shaft base, a flange and a plurality of lobes. The shaft base extends axially along an axis between a shaft first end and a shaft second end. The flange is connected to the shaft base at the shaft first end. The flange projects radially out from the shaft base. The flange includes a plurality of fastener apertures, and the fastener apertures include a first fastener aperture. The lobes are arranged circumferentially about the axis. Each of the lobes is connected to and projects radially away from the shaft base. Each of the lobes is connected to and projects axially out from the flange. The lobes include a first lobe and a second lobe. The first fastener aperture is arranged circumferentially between the first lobe and the second lobe. The second lobe radially overlaps the first fastener aperture.

Abstract: Aircraft power plants including combustion engines, and associated methods for recuperating waste heat from such aircraft power plants are described. A method includes transferring the heat rejected by the internal combustion engine to supercritical CO2 (sCO2) used as a working fluid in a heat engine. The heat engine converts at least some the heat transferred to the sCO2 to mechanical energy to perform useful work onboard the aircraft.

Abstract: The present disclosure provides methods and systems for operating a multi-engine rotorcraft. The method comprises driving a rotor of the rotorcraft with a first engine while a second engine is de-clutched from a transmission clutch system that couples the rotor and the second engine, instructing the second engine to accelerate to a re-clutching speed, and controlling an output shaft speed of the second engine during acceleration of the second engine to the re-clutching speed by applying a damping function to a speed control loop of the second engine.

Abstract: There is provided a blade angle feedback assembly for a propeller of an aircraft engine. The propeller is rotatable about an axis and has propeller blades rotatable about respective spanwise axes to adjust a blade angle thereof. The blade angle feedback assembly comprises a feedback ring having a plurality of position markers disposed thereon, at least one sensor configured to provide feedback on the blade angle of the propeller blades by detecting a relative movement between the feedback ring and the at least one sensor, and at least one shielding element provided between the feedback ring and the propeller, the at least one shielding element configured to shield the feedback ring from electromagnetism.

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: In accordance with at least one aspect of this disclosure, there is provided a system for an aircraft engine. In embodiments, the system includes an accessory box and a fuel accessory located in an interior space within the accessory box, where a vent is defined through a wall of the accessory box. In embodiments, the vent includes a plurality of holes or slots in an outer wall of the accessory box for passage of gaseous fuel from the interior space. In embodiments, the vent is configured for passive ventilation of the interior space.

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: 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.