Abstract: A method for tuning a vibration response of an aircraft system is disclosed, where the aircraft system comprises an airframe and at least one engine dynamically coupled, the at least one engine having an engine rotor including a nose cone. The method comprises obtaining a range of frequencies associated with at least one resonance mode of the aircraft system and adding mass within the nose cone to offset at least one dominant excitation frequency of the turbofan engine outside the range of frequencies associated with the at least one resonance mode of the aircraft system. A method of tuning dynamic coupling of an aircraft system comprising an airframe and an engine mounted thereto is also disclosed.

Abstract: A hybrid electric aircraft powerplant arrangement can include a first wing pair of powerplants for a first wing of an aircraft, the first wing pair comprising a first electric powerplant configured to drive a first air mover and a first heat engine powerplant configured to drive a second air mover separate from the first air mover. The arrangement can include a second wing pair of powerplants for a second wing of the aircraft, the second wing pair comprising a second electric powerplant configured to drive a third air mover separate from the first and second air movers, and a second heat engine powerplant configured to drive a fourth air mover separate from the first, second, and third air movers.

Abstract: A method for tuning a vibration response of an aircraft system is disclosed, where the aircraft system comprises an airframe and at least one engine dynamically coupled, the at least one engine having an engine rotor including a nose cone. The method comprises obtaining a range of frequencies associated with at least one resonance mode of the aircraft system and adding mass within the nose cone to offset at least one dominant excitation frequency of the turbofan engine outside the range of frequencies associated with the at least one resonance mode of the aircraft system. A method of tuning dynamic coupling of an aircraft system comprising an airframe and an engine mounted thereto is also disclosed.

Abstract: An auxiliary power unit for an aircraft includes a rotary intermittent internal combustion engine drivingly engaged to an engine shaft, a turbine section having an inlet in fluid communication with an outlet of the engine(s), the turbine section including at least one turbine compounded with the engine shaft, and a compressor having an inlet in fluid communication with an environment of the aircraft and an outlet in fluid communication with a bleed duct for providing bleed air to the aircraft, the compressor having a compressor rotor connected to a compressor shaft, the compressor shaft drivingly engaged to the engine shaft. The driving engagement between the compressor shaft and the engine shaft is configurable to provide at least two alternate speed ratios between the compressor shaft and the engine shaft.

Abstract: A turboprop engine assembly for an aircraft, including an internal combustion engine having a liquid coolant system, an air duct in fluid communication with an environment of the aircraft, a heat exchanger received within the air duct having coolant passages in fluid communication with the liquid coolant system and air passages air passages in fluid communication with the air duct, and an exhaust duct in fluid communication with an exhaust of the internal combustion engine. The exhaust duct has an outlet positioned within the air duct downstream of the heat exchanger and upstream of an outlet of the air duct, the outlet of the exhaust duct spaced inwardly from a peripheral wall of the air duct. In use, a flow of cooling air surrounds a flow of exhaust gases. A method of discharging air and exhaust gases in an turboprop engine assembly having an internal combustion engine is also discussed.

Abstract: An engine assembly for an aircraft, including an internal combustion engine having a liquid coolant system in fluid communication with a heat exchanger, an exhaust duct in fluid communication with air passages of the heat exchanger, a fan in fluid communication with the exhaust duct for driving a cooling air flow through the air passages of the heat exchanger and into the exhaust duct, and an intermediate duct in fluid communication with an exhaust of the engine and having an outlet positioned within the exhaust duct downstream of the fan and upstream of the outlet of the exhaust duct. The outlet of the intermediate duct is spaced inwardly from a peripheral wall of the exhaust duct. The engine assembly may be configured as an auxiliary power unit. A method of discharging air and exhaust gases in an auxiliary power unit having an internal combustion engine is also discussed.

Abstract: A compound cycle engine having a rotary internal combustion engine, a first turbine, and a second turbine is discussed. The exhaust port of the internal combustion engine is in fluid communication with the flowpath of the first turbine upstream of its rotor. The rotors of the first turbine and of each rotary unit drive a common load. The inlet of the second turbine is in fluid communication with the flowpath of the first turbine downstream of its rotor. The first turbine is configured as a velocity turbine and the first turbine has a pressure ratio smaller than that of the second turbine. A method of compounding a rotary engine is also discussed.

Abstract: An engine assembly including an engine core including at least one internal combustion engine each including a rotor sealingly and rotationally received within a respective internal cavity to provide rotating chambers of variable volume in the respective internal cavity, a compressor having an outlet in fluid communication with an inlet of the engine core, a first intake conduit in fluid communication with an inlet of the compressor and with a first source of air, a second intake conduit in fluid communication with the inlet of the compressor and with a second source of air warmer than the first source of air, and a selector valve configurable to selectively open and close at least the fluid communication between the inlet of the compressor and the first intake conduit. A method of supplying air to a compressor is also discussed.

Abstract: An engine assembly including an internal combustion engine configured to be received in an engine compartment and a heat exchanger having a first conduit fluidly connected to a fluid circuitry of the engine and a second conduit fluidly connecting an interior of the engine compartment to its environment. The first conduit is in heat exchange relationship with the second conduit. The assembly further includes a forced air system operable in use to provide an air flow from the environment to the outlet via the second conduit of the heat exchanger and the engine compartment. The assembly further includes a selector valve configurable to selectively fluidly connect an air intake of the internal combustion engine with the interior of the engine compartment in a first valve position and with the environment in a second valve position. A method for supplying air to an internal combustion engine is also discussed.

Abstract: An assembly for an aircraft having a propeller, including a wheel well configured for receiving a retracted landing gear, the wheel well including walls and a closable bottom opening for deploying the landing gear therethrough, an engine assembly having an engine shaft configured for driving engagement with the propeller, and a mount assembly for supporting the engine assembly, the mount assembly connected to at least one of the walls of the wheel well. A method of supporting an engine assembly in an aircraft having a retractable landing gear and a propeller driven by the engine assembly is also discussed.

Abstract: There is described a system and method for controlling a temperature in the subchamber of a rotary engine. At least one first measurement of at least one engine operating parameter, a second measurement of the actual value of a temperature in the subchamber, and at least one third measurement of at least one aircraft operating parameter are received. A setpoint for the temperature in the subchamber is determined from the at least one first measurement and the at least one third measurement. At least one control signal is output to the engine for adjusting the actual value of the temperature in the subchamber towards the setpoint.

Abstract: An integrated turbo-compressor includes a compressor with a compressor outlet, a turbine with a turbine inlet, the turbine operatively connected to the compressor by an interconnect shaft, and a compounding drive. The compounding drive is connected to the turbine and has a variable gear ratio and an output member, the variable gear ratio coupling the turbine to the output member to compound output of an internal combustion engine using energy recovered from an exhaust flow received from the internal combustion engine and in excess of energy required to compress combustion air provided to the internal combustion engine. Internal combustion engines, aircraft, and methods of compounding output of internal combustion engines are also described.

Abstract: An assembly for an aircraft having a propeller, including a wheel well for a retracted landing gear, first and second cooling ducts; and an engine assembly having an engine shaft configured for driving engagement with the propeller, the engine assembly including a coolant circulation system for circulation of a liquid coolant, a lubricant circulation system for circulation of a lubricant, a first heat exchanger in fluid communication with at least the coolant circulation system, and a second heat exchanger in fluid communication with at least the lubricant circulation system. Each heat exchanger is positioned and configured for receiving a cooling airflow from the respective cooling duct. The wheel well is located between the heat exchangers. A method of cooling a lubricant and a liquid coolant of an engine assembly is also discussed.

Abstract: An auxiliary power unit for an aircraft, having a compressor, an intercooler including first conduit(s) having an inlet in fluid communication with the compressor outlet and second conduit(s) configured for circulation of a coolant therethrough, an engine core having an inlet in fluid communication with an outlet of the first conduit(s), and a bleed conduit in fluid communication with the outlet of the first conduit(s) through a bleed air valve. The auxiliary power unit may include a generator in driving engagement with the shaft of the engine core to provide electrical power for the aircraft. A method of providing compressed air and electrical power to an aircraft is also discussed.

Abstract: A hybrid propulsion system includes a heat engine configured to drive a heat engine shaft. An electric motor is configured to drive an electric motor shaft. A transmission system includes at least one gearbox. The transmission system is configured to receive rotational input power from each of the heat engine shaft and the electric motor shaft and to convert the rotation input power to output power.

Abstract: A hybrid electric engine control module (ECU) configured to be operatively connected to a hybrid electric aircraft powerplant having a heat engine system and an electric motor system to control a torque output from each of the heat engine system and the electric motor system, the ECU being configured to determine whether the electric motor system and/or the heat engine system are in a normal mode such that the electric motor system and/or the heat engine can provide a predetermined amount of torque (e.g., full power). The ECU can be configured to receive a total torque setting and split output power between the electric motor system and the heat engine system in accordance with the normal mode as a function of the total torque setting. The ECU can be configured to detect and command recharging or regenerating of the battery system in some flight conditions.

Abstract: A hybrid electric engine control module (ECU) configured to be operatively connected to a hybrid electric aircraft powerplant having a heat engine system and an electric motor system to control a torque output from each of the heat engine system and the electric motor system. The ECU can be configured to receive a torque command and split output power between the electric motor system and the heat engine system. Additionally and/or alternatively, the ECU can be configured to balance a total torque against a second total torque of a second aircraft powerplant.

Abstract: A hybrid electric engine control module (ECU) can be configured to be operatively connected to a hybrid electric aircraft powerplant having a heat engine system and an electric motor system to control a torque output from each of the heat engine system and the electric motor system. The ECU can be configured to determine whether at least one of the electric motor system or the heat engine system are in a normal mode such that one of the electric motor system and/or the heat engine can provide a predetermined amount of torque. The ECU can be configured to switch to a degraded mode if either of the electric motor system or the heat engine system cannot provide the predetermined amount of torque. In the degraded mode the ECU can be configured to control the electric motor system and the heat engine system differently than in the normal mode or to not control one or both of the electric motor system or the heat engine system.

Abstract: An aircraft propulsion system having dual powerplants is disclosed that includes a combustion powerplant on one wing of the aircraft and a hybrid-electric powerplant on the other wing of the aircraft, wherein the combustion powerplant includes a gas turbine turboprop engine and the hybrid-electric powerplant includes a heat engine and an electric motor that are arranged in either a parallel drive configuration or an in-line drive configuration.

Abstract: An aircraft propulsion system is disclosed that includes at least one hybrid-electric powerplant for delivering power to an air mover for propelling the aircraft, wherein the at least one hybrid-electric powerplant includes a heat engine and an electric motor arranged in a parallel drive configuration or an in-line drive configuration.