Abstract: Systems and methods include providing an aircraft with a direct drive dual-concentric valve (D3V) having a body, an outer secondary spool coaxially located within a bore of the body and linearly displaceable relative to the body, an inner primary spool coaxially located within a bore of the secondary spool and linearly displaceable relative to the secondary spool and the body. A plurality of piezo stacks is coupled to a first end of the primary spool, and applying a voltage to at least one of the piezo stacks causes an output stroke of the plurality of the piezo strokes for displacing the primary spool. The secondary spool is displaced together with the primary spool relative to the body if displacement of the primary spool relative to the secondary spool cannot occur.

Abstract: A boundary layer utilization apparatus for intake of air to a high speed aircraft, comprises a first air inlet adjacent an exterior surface of a fuselage of the aircraft and offset from the fuselage enough to integrate a second air inlet in the offset space to ingest and divert the boundary layer air flowing next to the fuselage into the aircraft for a useful purpose such as cooling the engine compartment. The second air inlet is disposed aft of the first air inlet to minimize hot gas re-ingestion.

Abstract: A hydraulic system for an aircraft having an engine and an auxiliary power unit includes a first hydraulic subsystem including a first hydraulic pump and a first set of hydraulic-powered components in fluid communication with the first hydraulic pump. The first hydraulic pump is powered by the engine to pump shared hydraulic fluid to the first set of hydraulic-powered components. The hydraulic system includes a second hydraulic subsystem including a second hydraulic pump and a second set of hydraulic-powered components in fluid communication with the second hydraulic pump. The second hydraulic pump is powered by the auxiliary power unit to pump the shared hydraulic fluid to the second set of hydraulic-powered components. A shared return line subsystem and reservoir is in fluid communication with the first and second hydraulic subsystems to return the shared hydraulic fluid to the first and second hydraulic pumps.

Abstract: A boundary layer utilization apparatus for intake of air to a high speed aircraft, comprises a first air inlet adjacent an exterior surface of a fuselage of the aircraft and offset from the fuselage enough to integrate a second air inlet in the offset space to ingest and divert the boundary layer air flowing next to the fuselage into the aircraft for a useful purpose such as cooling the engine compartment. The second air inlet is disposed aft of the first air inlet to minimize hot gas re-ingestion.

Abstract: Systems and methods include providing an aircraft with a direct drive dual-concentric valve (D3V) having a body, an outer secondary spool coaxially located within a bore of the body and linearly displaceable relative to the body, an inner primary spool coaxially located within a bore of the secondary spool and linearly displaceable relative to the secondary spool and the body, and multiple motor assemblies coupled to the primary spool that provide selective displacement of the primary spool or the secondary spool. Each motor assembly includes a clutching mechanism that selectively couples a motor of the motor assembly to and from the primary spool.

Abstract: A hydraulic system for an aircraft having an engine and an auxiliary power unit includes a first hydraulic subsystem including a first hydraulic pump and a first set of hydraulic-powered components in fluid communication with the first hydraulic pump. The first hydraulic pump is powered by the engine to pump shared hydraulic fluid to the first set of hydraulic-powered components. The hydraulic system includes a second hydraulic subsystem including a second hydraulic pump and a second set of hydraulic-powered components in fluid communication with the second hydraulic pump. The second hydraulic pump is powered by the auxiliary power unit to pump the shared hydraulic fluid to the second set of hydraulic-powered components. A shared return line subsystem and reservoir is in fluid communication with the first and second hydraulic subsystems to return the shared hydraulic fluid to the first and second hydraulic pumps.