Abstract: An insulation assembly for use with an APU having an exhaust muffler is disclosed herein. The insulation assembly includes, but is not limited to, a first insulating member that is configured for placement on a top portion of the exhaust muffler and a second insulating member attached to the first insulating member and configured for placement on a bottom portion of the exhaust muffler. The second insulating member is less resistant to heat transfer than the first insulating member.

Abstract: A compressor scroll is provided for redirecting an airflow from a compressor. The compressor scroll includes a spiral-shaped body; a radial inlet formed in the body for receiving the airflow from the compressor as inlet airflow; and an outlet formed in the body such that inlet airflow flows through the body and exits the outlet as outlet airflow, with at least a portion of the outlet airflow crossing at least a portion of the inlet airflow.

Abstract: A ducted fan air-vehicle having a duct lip shape is described. The duct lip has an internal duct lip portion and an external duct lip portion, both of which are substantially curvature continuous around the circumference of the air duct. The duct has a plurality of cross-sections along its circumference and at least some of the plurality of cross-sections have a different shape. Further, each cross-section around the circumference of the duct has an a/b ratio and the a/b ratio for each cross-section is substantially the same.

Abstract: A ducted fan air-vehicle having a duct lip shape is described. The duct lip has an internal duct lip portion and an external duct lip portion, both of which are substantially curvature continuous around the circumference of the air duct. The duct has a plurality of cross-sections along its circumference and at least some of the plurality of cross-sections have a different shape. Further, each cross-section around the circumference of the duct has an a/b ratio and the a/b ratio for each cross-section is substantially the same.

Abstract: A ram door assembly is provided for an intake opening of an intake duct of an auxiliary power unit of an aircraft. The ram door assembly includes a ram door hingeably mounted adjacent to the intake opening and moveable between an open position to a closed position. The ram door has an interior surface and an exterior surface. The ram door assembly further includes a fairing positioned on the interior surface of the ram door.

Abstract: An insulation assembly for use with an APU having an exhaust muffler is disclosed herein. The insulation assembly includes, but is not limited to, a first insulating member that is configured for placement on a top portion of the exhaust muffler and a second insulating member attached to the first insulating member and configured for placement on a bottom portion of the exhaust muffler. The second insulating member is less resistant to heat transfer than the first insulating member.

Abstract: A strut support system for a ducted fan unmanned aerial vehicle to suppress noise comprising: a ducted fan fuselage that defines an opening; an engine that extends longitudinally through the opening in the fuselage; a drive mechanism rotatably mounted to the engine, wherein a fan is mounted on the drive mechanism within a duct defined by the opening; and a plurality of struts extending between the ducted fan fuselage and the engine each comprising a first leg and a second leg joined together by a curvilinear junction, wherein the first leg is attached to the ducted fan fuselage and the second leg is attached to the engine, wherein the plurality of struts are positioned upstream of the fan, wherein the junction between the first leg of each of the plurality of struts and the ducted fan fuselage is outside the highlight of the ducted fan fuselage's leading edge.

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.

Abstract: A ram door assembly is provided for an intake opening of an intake duct of an auxiliary power unit of an aircraft. The ram door assembly includes a ram door hingeably mounted adjacent to the intake opening and moveable between an open position to a closed position. The ram door has an interior surface and an exterior surface. The ram door assembly further includes a fairing positioned on the interior surface of the ram door.

Abstract: A strut support system for a ducted fan unmanned aerial vehicle to suppress noise comprising: a ducted fan fuselage that defines an opening; an engine that extends longitudinally through the opening in the fuselage; a drive mechanism rotatably mounted to the engine, wherein a fan is mounted on the drive mechanism within a duct defined by the opening; and a plurality of struts extending between the ducted fan fuselage and the engine each comprising a first leg and a second leg joined together by a curvilinear junction, wherein the first leg is attached to the ducted fan fuselage and the second leg is attached to the engine, wherein the plurality of struts are positioned upstream of the fan, wherein the junction between the first leg of each of the plurality of struts and the ducted fan fuselage is outside the highlight of the ducted fan fuselage's leading edge.

Abstract: A compressor scroll is provided for redirecting an airflow from a compressor. The compressor scroll includes a spiral-shaped body; a radial inlet formed in the body for receiving the airflow from the compressor as inlet airflow; and an outlet formed in the body such that inlet airflow flows through the body and exits the outlet as outlet airflow, with at least a portion of the outlet airflow crossing at least a portion of the inlet airflow.