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.

A Laminar Inducing Apparatus (LIA) inducing laminar airflow to a turbine engine or a propulsion fan. The LIA produces turbulent-free airflow with a light aerospace structure that can replace single purpose structure in the wing or empennage. Laminar airflow to the propulsion fan or the turbine engine is ensured in a greater number of flight conditions and angles of attack. Active control of flight can be enhanced by the manipulating the turbulent boundary surface as a flight control surface. LIA simply reduces the risk of FOD or bird strike damage. In addition to the engineered, laminar benefits, LIA provides greater safety from ground ingested FOD and more silent vertical take-off and landing. In summary, LIA ensures laminar airflow and acoustic attenuation to a propulsion fan or a turbine engine for a greater number of flight conditions, angles of attack, and from ground ingested FOD during vertical takeoff and landing.

A system to predict a startup condition of an auxiliary power unit (APU) of an aircraft includes a machine learning device configured to receive data including sensor data of the aircraft and weather forecast data of a destination airport. The machine learning device is also configured to process the data to generate a prediction regarding the startup condition and to generate a message based on the prediction. The message indicates that an alternate startup procedure of the APU is to be performed after the aircraft has landed at the destination airport to avoid an error condition associated with a primary startup procedure of the APU.

This disclosure relates to a support device for an actuator. The support device includes a support unit adapted to be mounted to a stationary structure, an attachment unit adapted to be attached to an actuator casing and a single pivot shaft, and the attachment unit is pivotably connected to the support unit via the single pivot shaft. The support device according to the present disclosure has a simple structure and is stable in operation. The present disclosure further relates to an air intake system for an auxiliary power unit, which includes the above support device for the actuator. In addition, the present disclosure further relates to an aircraft including the air intake system for the auxiliary power unit.

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.

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.

The invention concerns a structure (3) for feeding air to an auxiliary power unit (2) of an aircraft (1) comprising a pressurized cabin (10) and an auxiliary power unit (2), the structure comprising: a pipe (30) for feeding air to the auxiliary power unit; a unit (4) for controlling the airflow fed to the auxiliary power unit; and a valve (31) for the intake of air outside the aircraft, disposed at the inlet of the feed pipe (30), the opening of the valve being driven by the control unit (4). The structure is characterized in that it further comprises a circuit (32) for injecting air from the pressurized cabin into the auxiliary power unit feed pipe. The invention also concerns a method for feeding air to an auxiliary power unit.

Auxiliary power systems, aircraft including the same, and related methods are disclosed herein. In one embodiment, the aircraft includes an airframe and an auxiliary power system that includes an auxiliary power unit (APU), an APU controller, and a bleed air temperature (BAT) sensor. The APU defines a bleed air outlet and is configured to regulate a BAT of a bleed air flow generated by the auxiliary power unit. The BAT sensor is positioned at a remote BAT location that is outside the bleed air outlet of the APU. In another embodiment, the auxiliary power system includes an APU configured to generate a bleed air flow, an APU controller configured to receive and transmit signals, and a BAT sensor suite configured to measure the BAT of the bleed air flow and to generate a BAT signal that is based, at least in part, on the BAT.

Auxiliary power unit inlet apparatus and methods are disclosed. An example apparatus includes an aircraft including a fuselage, the fuselage including an air inlet including a first sub-inlet and a second sub-inlet separated from the first sub-inlet; and a door coupled along the air inlet to enable air to separably flow into the first sub-inlet and the second sub-inlet, the door to deter the air from flowing between the first sub-inlet and the second sub-inlet.

A fire seal structure prevents flame from coming out of a fire-prevention region of an aircraft including a panel and a duct. The fire seal structure includes: a first member provided on the duct at a connection portion between the panel and the duct; and a second member that faces the first member around the opening and is provided on the panel. The panel defines the fire-prevention region. The duct communicates with an opening provided in the panel. The duct defines, together with the panel, the fire-prevention region. The first and the second members each contain refractory material, and the first and the second members form a labyrinth-shaped gap between the duct and the panel.