Abstract: A system for delivering a flow stream of a gas to a compressor. A shroud extends from an inlet to the compressor and defines a main inlet passage configured to direct the flow stream from the inlet to the compressor. A communication plenum is separated from the main inlet passage. A port system includes first and second port subsystems that each provide an opening between the main inlet passage and the communication plenum. The first port subsystem is disposed further from the compressor than the second port subsystem. The port system is configured so that a portion of the gas enters or exits the compressor through the second port subsystem, depending on operating conditions of the compressor.

Abstract: A turboprop engine system for an aircraft includes an engine, a propeller, and a gear train coupled to and configured to provide power from the engine to the propeller at a predetermined gear reduction. The engine system also includes a gearbox that houses at least part of the gear train. The gearbox includes a gearbox flow structure and an inlet flow structure that is removably attached to the gearbox. The inlet flow structure and the gearbox flow structure cooperate to define an inlet flow passage to the engine. The inlet flow passage has an upstream end and a downstream end that are cooperatively defined by the inlet flow structure and the gearbox flow structure. The upstream end is configured to receive an airstream that is directed along the inlet flow passage to the downstream end and toward the engine.

Abstract: A turboprop engine system for an aircraft includes an engine, a propeller, and a gear train coupled to and configured to provide power from the engine to the propeller at a predetermined gear reduction. The engine system also includes a gearbox that houses at least part of the gear train. The gearbox includes a gearbox flow structure and an inlet flow structure that is removably attached to the gearbox. The inlet flow structure and the gearbox flow structure cooperate to define an inlet flow passage to the engine. The inlet flow passage has an upstream end and a downstream end that are cooperatively defined by the inlet flow structure and the gearbox flow structure. The upstream end is configured to receive an airstream that is directed along the inlet flow passage to the downstream end and toward the engine.

Abstract: A system for delivering a flow stream of a gas to a compressor. A shroud extends from an inlet to the compressor and defines a main inlet passage configured to direct the flow stream from the inlet to the compressor. A communication plenum is separated from the main inlet passage. A port system includes first and second port subsystems that each provide an opening between the main inlet passage and the communication plenum. The first port subsystem is disposed further from the compressor than the second port subsystem. The port system is configured so that a portion of the gas enters or exits the compressor through the second port subsystem, depending on operating conditions of the compressor.

Abstract: Eductor systems and methods improve eduction by increasing swirl. An eductor housing defines a primary plenum channeling a flow stream from an inlet opening to an exit opening, and defines a secondary plenum separated from the primary plenum and channeling another flow stream from a duct inlet to exit slots. A gas flow stream is delivered into the eductor housing and is directed through the exit opening so that the gas flow stream educes the flow stream through the inlet opening and the exit opening. The second flow stream is delivered to the secondary plenum through a duct connected at an angle to induce a swirl in the secondary plenum to effect a static pressure reduction at the exit opening that draws the flow stream from the inlet opening through the exit opening.

Abstract: An outflow valve is provided. The outflow valve includes a frame and a first door rotatably coupled to the frame. The first door has a first side opposite a second side and a bellmouth. The bellmouth is defined by a super-ellipse, with a major axis of the super-ellipse substantially parallel to the second side and a minor axis of the super-ellipse substantially perpendicular to the second side. The outflow valve also includes a second door rotatably coupled to the frame. The first door and the second door are substantially simultaneously movable between at least a first position and a second position.

Abstract: Eductor systems and methods improve eduction by increasing swirl. An eductor housing defines a primary plenum channeling a flow stream from an inlet opening to an exit opening, and defines a secondary plenum separated from the primary plenum and channeling another flow stream from a duct inlet to exit slots. A gas flow stream is delivered into the eductor housing and is directed through the exit opening so that the gas flow stream educes the flow stream through the inlet opening and the exit opening. The second flow stream is delivered to the secondary plenum through a duct connected at an angle to induce a swirl in the secondary plenum to effect a static pressure reduction at the exit opening that draws the flow stream from the inlet opening through the exit opening.

Abstract: An inlet particle separator system for a vehicle engine includes a hub section, a shroud section, and a splitter. The hub section has a hub outer surface that diverges, relative to the axis of symmetry, to a hub apex. The shroud section has a shroud inner surface that surrounds, and is spaced apart from, at least a portion of the hub section to define a main flow passageway between the hub outer surface and the shroud inner surface. The splitter is disposed downstream of the air inlet and extends into the main flow passageway to divide the main flow passageway into a scavenge flow path and an engine flow path. The hub section and the shroud section are configured such that the cross sectional flow area of the main flow passageway decreases downstream of the air inlet to define a throat section that is disposed upstream of the hub apex.

Abstract: A multi-channel particle separator includes a plurality of vanes. Each vane is spaced apart from at least one other adjacent vane to define a flow channel, and includes a leading edge, a trailing edge, a first side wall, a second sidewall, and a splitter. The first side wall extends between the leading edge and the trailing edge. The second side wall is spaced apart from the first side wall and extends from the leading edge toward the trailing edge. The splitter may be rotationally coupled to the trailing edge and extend toward the leading edge. The splitter is spaced apart from the first side wall to define a scavenge volume and is rotatable between an extended position and a retracted position. The vanes may also or instead be coupled to a ring-shaped structure.

Abstract: An inlet particle separator system includes a shroud section and a hub section that is at least partly surrounded by the shroud section. The hub section is spaced apart from the shroud section. The inlet particle separator system also includes a flow passageway with an air inlet defined between the hub section and the shroud section. The flow passageway branches downstream of the air inlet into a main passage and a pre-cleaner passage. The main passage is defined between the hub section and the shroud section. The pre-cleaner passage includes a pre-cleaner inlet and extends at least partially through the hub section. Furthermore, the system includes a splitter that divides the main passage into scavenge and engine flow paths. The pre-cleaner inlet is partly defined by a first surface of the hub section. The first surface faces substantially in an upstream direction toward the air inlet.

Abstract: A compartment based inlet particle separator system for an aircraft that includes an auxiliary power unit (APU) system compartment is provided. The system includes a separation barrier wall, a ram air inlet opening, a diffuser, and an inlet particle separator (IPS). The separation barrier wall is disposed within the APU system compartment and divides the APU system compartment into two compartments. The ram air inlet opening is formed one of the compartments. The diffuser receives ram air from a ram air inlet opening and discharges ram air into a compartment. The IPS is disposed within the a compartment between the diffuser outlet and the APU air inlet port.

Abstract: An inlet particle separator system for a vehicle engine includes a hub section, a shroud section, and a splitter. The hub section has a hub outer surface that diverges, relative to the axis of symmetry, to a hub apex. The shroud section has a shroud inner surface that surrounds, and is spaced apart from, at least a portion of the hub section to define a main flow passageway between the hub outer surface and the shroud inner surface. The splitter is disposed downstream of the air inlet and extends into the main flow passageway to divide the main flow passageway into a scavenge flow path and an engine flow path. The hub section and the shroud section are configured such that the cross sectional flow area of the main flow passageway decreases downstream of the air inlet to define a throat section that is disposed upstream of the hub apex.

Abstract: An outflow valve is provided. The outflow valve includes a frame and a first door rotatably coupled to the frame. The first door has a first side opposite a second side and a bellmouth. The bellmouth is defined by a super-ellipse, with a major axis of the super-ellipse substantially parallel to the second side and a minor axis of the super-ellipse substantially perpendicular to the second side. The outflow valve also includes a second door rotatably coupled to the frame. The first door and the second door are substantially simultaneously movable between at least a first position and a second position.

Abstract: A multi-channel particle separator includes a plurality of vanes. Each vane is spaced apart from at least one other adjacent vane to define a flow channel, and includes a leading edge, a trailing edge, a first side wall, a second sidewall, and a splitter. The first side wall extends between the leading edge and the trailing edge. The second side wall is spaced apart from the first side wall and extends from the leading edge toward the trailing edge. The splitter may be rotationally coupled to the trailing edge and extend toward the leading edge. The splitter is spaced apart from the first side wall to define a scavenge volume and is rotatable between an extended position and a retracted position. The vanes may also or instead be coupled to a ring-shaped structure.

Abstract: A compartment based inlet particle separator system for an aircraft that includes an auxiliary power unit (APU) system compartment is provided. The system includes a separation barrier wall, a ram air inlet opening, a diffuser, and an inlet particle separator (IPS). The separation barrier wall is disposed within the APU system compartment and divides the APU system compartment into two compartments. The ram air inlet opening is formed one of the compartments. The diffuser receives ram air from a ram air inlet opening and discharges ram air into a compartment. The IPS is disposed within the a compartment between the diffuser outlet and the APU air inlet port.

Abstract: An inlet door system includes a duct, an inlet door, and a plurality of openings. The duct is configured to extend from the auxiliary power unit (APU) to an intake opening formed in an outer surface of an aircraft. The duct includes an inlet port, an outlet port, and a duct sidewall extending between the inlet port and the outlet port. The inlet door includes an inner surface, an outer surface, and an outer peripheral edge between the inner and outer surfaces. The door is rotationally coupled to the duct, and is configured to selectively rotate between a closed position and a plurality of open positions. The openings extend through the inlet door between the inner surface and outer surface, and each opening is disposed adjacent to the outer peripheral edge.

Abstract: An inlet door system includes a duct, an inlet door, and a plurality of openings. The duct is configured to extend from the auxiliary power unit (APU) to an intake opening formed in an outer surface of an aircraft. The duct includes an inlet port, an outlet port, and a duct sidewall extending between the inlet port and the outlet port. The inlet door includes an inner surface, an outer surface, and an outer peripheral edge between the inner and outer surfaces. The door is rotationally coupled to the duct, and is configured to selectively rotate between a closed position and a plurality of open positions. The openings extend through the inlet door between the inner surface and outer surface, and each opening is disposed adjacent to the outer peripheral edge.

Abstract: An eductor assembly comprises a primary nozzle configured to discharge turbine exhaust gas therefrom. The eductor assembly further comprises a cooler plenum having an inlet and an outlet and a surge plenum at least partially surrounding the cooler plenum and the nozzle, the surge plenum for conducting a surge flow. Cooling air flows through a vent between the cooler plenum and the surge plenum when there is no surge flow.

Abstract: An eductor assembly comprises a primary nozzle configured to discharge turbine exhaust gas therefrom. The eductor assembly further comprises a cooler plenum having an inlet and an outlet and a surge plenum at least partially surrounding the cooler plenum and the nozzle, the surge plenum for conducting a surge flow. Cooling air flows through a vent between the cooler plenum and the surge plenum when there is no surge flow.

Abstract: Assemblies for cooling an aft bearing assembly mounted to a rotor are provided. An assembly includes a static aft bearing structure configured to surround the aft bearing assembly and including a cylindrical section defining a cavity for disposal of the aft bearing assembly, a plurality of hollow struts extending from the static aft bearing structure, each hollow strut including an outer radial end configured to receive a gas from an air source and to provide a pathway for the gas to flow into the cavity, and a center-body cap disposed over an end of the static aft bearing structure, the center-body cap including a rim configured to create a low pressure region at an interface between the static aft bearing structure and the center-body cap, wherein the low pressure region has a pressure that is lower than a pressure within the cavity.