Abstract: A bearing support assembly includes a squirrel cage defining a longitudinal axis and having a cylindrical portion defining a bearing seat. The squirrel cage is configured and adapted to provide a first level of radial support stiffness between a housing and a bearing seated in the bearing seat. A damper sleeve is operatively coupled to the cylindrical portion of the squirrel cage through a fluid film to dampen relative radial motion between the damper sleeve and the squirrel cage. A radial spring component is operatively connected to a side of the damper sleeve radially opposite the cylindrical portion of the squirrel cage to provide a second level of radial support stiffness.

Abstract: An aircraft system includes a component configured to operate with a minimum power demand. The aircraft system also includes an auxiliary power unit including an engine. The auxiliary power unit is configured to power the component and to operate the engine in a plurality of operating modes including a power mode and a standby mode. The auxiliary power unit generates a first power output at least equal to the minimum power demand during the power mode. The auxiliary power unit generates a second power output less than the minimum power demand during the standby mode.

Abstract: Systems and methods of monitoring health of rotating engine components are provided. The systems and methods may receive a measurement from a speed sensor, detect the measurement from the speed sensor indicates a vibration of an engine, determine the vibration of the engine persisted for a predetermined duration, and signal the vibration of the engine is detected.

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: An auxiliary power unit for an aircraft includes a turbine engine. An inlet includes an opening and a passageway between the opening and the turbine engine. An acoustic aplitter is supported within the passageway for attenuating noise within the inlet. An inlet door is movable between a closed position and a fully open position. A portion of the inlet door aligns with a part of the passageway in at least a first position and divides the passageway to deflect ice and noise in at least a second position. An air inlet and a method are also disclosed.

Abstract: A technique for mounting a turbine retention device is provided. The technique comprises forming openings in a diffuser, aligning a mounting bracket with the openings, and installing fasteners through the openings and the mounting bracket. A turbine retention device mounted to a diffuser may is also provided. The turbine retention device may comprise a bullet, wings coupled to the bullet, mounting brackets coupled to the wings, and fasteners disposed through the mounting brackets and openings formed in the diffuser.

Abstract: A turbine retention device is made by forming a bullet having a cylindrical geometry, forming a wing, coupling the wing to the bullet with a proximal portion of the wing along an axial length of the bullet, and coupling a mounting bracket to a distal end of the wing.

Abstract: A bearing support assembly includes a squirrel cage defining a longitudinal axis and having a cylindrical portion defining a bearing seat. The squirrel cage is configured and adapted to provide a first level of radial support stiffness between a housing and a bearing seated in the bearing seat. A damper sleeve is operatively coupled to the cylindrical portion of the squirrel cage through a fluid film to dampen relative radial motion between the damper sleeve and the squirrel cage. A radial spring component is operatively connected to a side of the damper sleeve radially opposite the cylindrical portion of the squirrel cage to provide a second level of radial support stiffness.

Abstract: A fuel system for an auxiliary power unit includes a mechanical fuel pump, an electric fuel pump, and a controller. The mechanical fuel pump provides fuel flow to the auxiliary power unit and has an output dependent upon an operational speed of the auxiliary power unit. The electric fuel pump provides fuel flow to the auxiliary power unit, and is located in flow series with the mechanical fuel pump. The controller causes the electric fuel pump to provide fuel flow during starting of the auxiliary power unit.

Abstract: An exemplary pressure influencing assembly for an aircraft auxiliary system an inlet opening to an aircraft auxiliary system and an exhaust opening from the aircraft auxiliary system. Both the inlet opening and the exhaust opening face at least partially radially away from an axis. At least some of the inlet opening is circumferentially aligned with at least some of the exhaust opening relative to the axis.

Abstract: The presently disclosed embodiments utilize an ice separator vessel to trap ice particles in a non-homogeneous ice/fuel mixture flowing in a fuel system. A source of heat, such as heated fuel provided to the ice separator vessel, is used to melt at least a portion of the ice particles so that they do not enter the fuel system downstream of the ice separator vessel.

Abstract: According to one aspect of the present invention, a preloaded hybrid duplex bearing assembly is disclosed. A hybrid duplex ball bearing assembly includes a forward bearing, an aft bearing, and a preload spring, the preload spring disposed adjacent the aft bearing and configured to apply an axial force to push the aft bearing toward the forward bearing, where the forward bearing and aft bearing share an inner race. The forward bearing and the aft bearing are angular contact bearings each including a contact angle, and the contact angles of the forward bearing and the aft bearing converge at a point within the bearing assembly. In one embodiment, the aft bearing is not radially loaded and carries only the axial force of the preload spring. In at least one embodiment, the forward bearing forms a radial clearance fit with the aft bearing such that the aft bearing carries no radial load.

Abstract: A fuel system for an auxiliary power unit includes a mechanical fuel pump, an electric fuel pump, and a controller. The mechanical fuel pump provides fuel flow to the auxiliary power unit and has an output dependent upon an operational speed of the auxiliary power unit. The electric fuel pump is located in flow series with the mechanical fuel pump. The controller causes the electric fuel pump to circulate and thereby warm fuel prior to start up of the auxiliary power unit.

Abstract: A catcher for a gas turbine engine includes a central hub, a plurality of struts, and a first ring. The plurality of struts are connected to and extend outward from the central hub. The first ring is connected to a mid-section of the plurality of struts and extends therebetween.

Abstract: A combination fuel-oil and air-oil heat exchanger comprising: a first heat exchanger section that has an oil circulation path and a fuel circulation path thermally coupled to the oil circulation path; a second heat exchanger section that has an oil circulation path and an air circulation path thermally coupled to the oil circulation path; an oil coupling path that couples an oil circulation path outlet of the first heat exchanger section to an oil circulation path inlet of the second heat exchanger section to establish a combined oil circulation path; an oil path by-pass valve that selectively diverts oil from the combined oil circulation path to an outlet of the oil path by-pass valve; and a fuel path by-pass valve that selectively diverts fuel from the fuel circulation path of the first heat exchanger section to an outlet of the fuel path by-pass valve.

Abstract: An impeller for use in a containment structure has a hub, a blade attaching to the hub for compressing air as the blade rotates with the hub, and an annulus disposed about the hub whereby the annulus reduces an effect of the hub breaking apart such that a weight of the containment structure is reduced.

Abstract: A catcher for a gas turbine engine includes a central hub, a plurality of struts, and a first ring. The plurality of struts are connected to and extend outward from the central hub. The first ring is connected to a mid-section of the plurality of struts and extends therebetween.

Abstract: A fuel system for an auxiliary power unit includes a mechanical fuel pump, an electric fuel pump, and a controller. The mechanical fuel pump provides fuel flow to the auxiliary power unit and has an output dependent upon an operational speed of the auxiliary power unit. The electric fuel pump provides fuel flow to the auxiliary power unit, and is located in flow series with the mechanical fuel pump. The controller causes the electric fuel pump to provide fuel flow during starting of the auxiliary power unit.

Abstract: A fuel system for an auxiliary power unit includes a mechanical fuel pump, an electric fuel pump, and a controller. The mechanical fuel pump provides fuel flow to the auxiliary power unit and has an output dependent upon an operational speed of the auxiliary power unit. The electric fuel pump is located in flow series with the mechanical fuel pump. The controller causes the electric fuel pump to circulate and thereby warm fuel prior to start up of the auxiliary power unit.

Abstract: An example ice separator device includes an ice separator that removes ice particles from a flow of fuel moving through the ice separator.