Systems and methods are presented for acoustic dampening in a rotating machine. The rotating machine has a rotatable shaft defining an axis of rotation and a gas flowpath. A system comprises an acoustic panel affixed to an annular casing. The acoustic panel comprises an acoustic treatment member extending between a radially inner skin and radially outer skin. The radially inner skin extends the full axial and circumferential dimensions of the acoustic panel, and the acoustic treatment member overlays the entirety of the radially inner skin. The acoustic panel is positioned so that the radially outer skin abuts the casing, the abutting surfaces being configured to effect relative axial movement between the surfaces while maintaining contact between the surfaces. The acoustic panel is affixed in position to the casing by one or more fasteners passing through the casing and a portion of the radially outer skin.

In an air mobility vehicle, an engine operates as required to provide mechanical driving force or electric energy. A battery is charged with the electric energy from the engine. Main rotors operate using the electric energy of the battery and electric power generated by the engine to perform takeoff, landing, and cruising. Auxiliary rotors are disposed at or adjacent to the center of gravity of a vehicle body and mechanically connected to the engine via a clutch. The auxiliary rotors perform the takeoff, the landing, or the cruising by receiving the mechanical driving force from the engine when the clutch is in an engaged position. A controller monitors the states of the battery and the main rotors and controls the operations of the engine and the clutch.

An airplane has main propulsion engines and a first fuel supply for the main propulsion engines. The airplane further has an auxiliary propulsion engine and a second fuel supply for the auxiliary propulsion engine, this second fuel supply being separate from the first fuel supply. The auxiliary propulsion engine can be switched on independently from the main propulsion engines. Such airplane has increased safety, since it will be possible to maintain flight, particularly when at high altitude, even if all main propulsion engines have failed.

Engine bleed air power recovery systems and related methods are disclosed. An example power recovery system for an aircraft engine includes a power recovery turbine coupled to aa shaft-driven device. A bleed air valve coupled between the power recovery turbine and a bleed air source. A controller configured to operate the bleed air valve to allow bleed air to flow to the power recovery turbine when the aircraft engine operates in a predetermined mode of operation.

The invention relates to an aircraft incorporating an enhanced power unit for generating electric, pneumatic and/or hydraulic power for the aircraft during all stages of the aircraft operation. The power unit (1) comprises: a heat engine (14) with a drive shaft (2) and a combustion gases exhaust (7). The power unit (1) also includes a Rankine cycle system (12) for recovering thermal energy from a heat source of the power unit (1) for the assistance of the heat engine (14). The heat source for the Rankine cycle system can be taken from the exhaust gases of the heat engine, from the oil coolant circuit of the heat engine or from the output of a compressor driven by the heat engine. Preferably, the aircraft cabin air is reused as a source of oxygen for the combustion. The invention reduces bleed air extraction from the aircraft main engines thereby reducing fuel consumption.

An aircraft heating assembly including an internal combustion engine having a liquid coolant system distinct from any fuel and lubricating system of the engine and including cooling passages in the internal combustion engine for circulating a liquid coolant from a coolant inlet to a coolant outlet, a coolant circulation path outside of the internal combustion engine and in fluid communication with the coolant inlet and the coolant outlet, and a heating element in heat exchange relationship with a portion of the aircraft to be heated. The coolant circulation path extends through a heat exchanger configured to remove a portion of a waste heat from the liquid coolant. The heating element is in heat exchange relationship with the coolant circulation path to receive another portion of the waste heat therefrom. A method of heating a portion of an aircraft is also discussed.

Engine bleed air power recovery systems and related methods are disclosed. An example power recovery system for an aircraft engine includes a power recovery turbine coupled to aa shaft-driven device. A bleed air valve coupled between the power recovery turbine and a bleed air source. A controller configured to operate the bleed air valve to allow bleed air to flow to the power recovery turbine when the aircraft engine operates in a predetermined mode of operation.

In an air mobility vehicle, an engine operates as required to provide mechanical driving force or electric energy. A battery is charged with the electric energy from the engine. Main rotors operate using the electric energy of the battery and electric power generated by the engine to perform takeoff, landing, and cruising. Auxiliary rotors are disposed at or adjacent to the center of gravity of a vehicle body and mechanically connected to the engine via a clutch. The auxiliary rotors perform the takeoff, the landing, or the cruising by receiving the mechanical driving force from the engine when the clutch is in an engaged position. A controller monitors the states of the battery and the main rotors and controls the operations of the engine and the clutch.

An aircraft auxiliary power unit is equipped with a charging compressor. A method determines a surge parameter indicative of a risk that the charging compressor will display the phenomenon known as surge. A method and a system control a relief valve of this charging compressor. The method for determining the surge parameter includes calculating this surge parameter Ppomp as being the sum of a first term T1 and of a second term T2, the first term T1 being calculated on the basis of a first pressure P1 measured downstream of a diffuser of the charging compressor, and of a second pressure P2 measured upstream of the diffuser, the second term T2 being calculated on the basis of a third pressure P3 measured upstream of the diffuser and of an ambient pressure Psamb indicative of a pressure of an ambient environment.

A system and method for adaptively controlling a cooldown cycle of an auxiliary power unit (APU) that is operating and rotating at a rotational speed includes reducing the rotational speed of the APU to a predetermined cooldown speed magnitude that ensures combustor inlet temperature has reached a predetermined temperature value, determining, based on one or more of operational parameters of the APU, when a lean blowout of the APU is either imminent or has occurred, and when a lean blowout is imminent or has occurred, varying one or more parameters associated with the shutdown/cooldown cycle.