An air inlet system for an auxiliary power unit (APU) has an intake duct having a wall defining an inlet plenum and forming an inlet opening configured to direct air into the inlet plenum. The system further comprising a load compressor passage in fluid communication with the inlet plenum and leading to a load compressor of the APU; and a core compressor passage in fluid communication with the inlet plenum and leading to a core compressor of the APU. A deflector is provided in the inlet plenum between the inlet opening and the core compressor inlet to deflect at least part of particles carried by an incoming airflow away from the core compressor inlet toward the load compressor inlet.

An air intake system comprising an air duct suitable for providing airflow to the inside of an aircraft, preferably to an auxiliary power unit; an inlet arranged at one end of the air duct; a skin surrounding the inlet; a plurality of slots arranged on the skin; a driving arrangement, a flap door connected to the driving arrangement, and a plurality of fins connected to the driving means. The driving arrangement is configured for moving the flap door between at least two positions, the positions being a closed position wherein the flap door closes the inlet, and an opened position wherein the flap door is driven away from the closed position. The driving arrangement is also configured for moving the plurality of fins such that the plurality of fins protrudes through the slots.

An inlet assembly for an auxiliary power unit for an aircraft, including a particle separator and a plenum having first and second inlets. A first duct configured to deliver air to an engine of the auxiliary power unit is in fluid communication with an outlet of the plenum. A second duct configured to deliver air to a compartment containing the auxiliary power unit is in fluid communication with the outlet of the plenum. The assembly is selectively configurable between a first configuration where the plenum is in fluid communication with the environment of the aircraft through the second inlet and through the particle separator, and a second configuration where the plenum is in fluid communication with the environment of the aircraft through the first inlet independently of the particle separator. An auxiliary power unit assembly and a method of feeding air to an auxiliary power unit assembly are also discussed.

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 includes a fuselage, a main entry door with an associated passenger loading zone, an auxiliary power unit (APU) in the fuselage, and an APU inlet assembly. The APU inlet assembly has an inlet duct, and inlet door, and means for redirecting sound waves coupled to or integrated with an interior side of the inlet door. The inlet duct has a first end coupled to the APU, and a second end associated with the inlet door. The inlet door moves between a closed position and an open position. The means for redirecting sound waves is positioned at a particular location on the interior side of the inlet door, and includes certain acoustic features and characteristics. The particular location and the acoustic features and characteristics cooperate to redirect sound waves generated by the APU away from the passenger loading zone when the inlet door is in the open position.

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 inlet assembly for an auxiliary power unit for an aircraft, including a duct configured to provide fluid communication from an environment of the aircraft to an inlet of an engine of the auxiliary power unit, and a filter received in and extending across the duct. The filter includes a first filter portion permeable to air, positioned across only part of the duct and defining a transverse edge in the duct; a second filter portion permeable to air and extending from the transverse edge to an end downstream of the transverse edge, and a collection member impermeable to water. The collection member extends between the downstream end and a duct wall. The first and second filter portions are non-parallel and the second filter portion and the collection member are non-parallel. An auxiliary power unit assembly and a method of feeding air to an internal combustion engine are also discussed.

A system and method for controlling a position of an inlet door of an auxiliary power unit are provided. A first control signal comprising instructions for opening the inlet door to a selected one of at least a first position and a second position is output. A possible failure in a feedback signal associated with the selected one of the at least first position and second position is detected and a second control signal comprising instructions for opening the inlet door to the other one of the at least first position and second position is then output.

An auxetic bi-stable structure that comprises an auxetic curved shell movable between a first and a second stable position, and a rigid element. At least part of the surface of the auxetic curved shell is joined to the rigid element such that the curved shell is movable with respect to the rigid element between the first and second stable positions.

An aircraft removable equipment fitting device, the aircraft comprising a structure to which the removable equipment is configured to be attached. The aircraft removable equipment fitting device includes a first coupling configured to be joined to the aircraft structure, a second coupling configured to be joined to the removable equipment and to be coupled to the first coupling, and a fastener configured to tighten the removable equipment and the second coupling to the first coupling so that the removable equipment is fastened to the aircraft structure.