An engine system has a gas generator, a bi-fi wall surrounding at least a portion of the gas generator, a casing surrounding a fan, and the casing having first and second thrust reverser doors which in a deployed position abut each other and the bi-fi wall.

An engine system has a gas generator, a bi-fi wall surrounding at least a portion of the gas generator, a casing surrounding a fan, and the casing having first and second thrust reverser doors which in a deployed position abut each other and the bi-fi wall.

Technologies are described herein for a drag recovery scheme using a boundary layer bypass duct system. In some examples, boundary layer air is routed around the intake of one or more of the engines and reintroduced aft of the engine fan in the nozzle duct in a mixer-ejector scheme. Mixer-ejectors mix the boundary layer flow to increase mass flow.

Technologies are described herein for a drag recovery scheme using a boundary layer bypass duct system. In some examples, boundary layer air is routed around the intake of one or more of the engines and reintroduced aft of the engine fan in the nozzle duct in a mixer-ejector scheme. Mixer-ejectors mix the boundary layer flow to increase mass flow.

A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle (501) defining a duct (502), and a fan (503) located within the duct. The fan comprises a hub arranged to rotate around a rotational axis (A-A) and a plurality of blades attached to the hub. Each blade has a span (r) from a root at the hub defining a 0 percent span position (r=0) to a tip defining a 100 percent span position (r=1) and a plurality of span positions therebetween (r ∈ [0, 1]), and a stagger angle at the 0 percent span position (ζ.sub.hub) relative to the rotational axis of 40 degrees or greater.

An aircraft is disclosed having a boundary layer ingestion propulsor. The aircraft comprises an elongated fuselage extending between a nose section and a tail section. The fuselage has an upswept underside in the tail section. The boundary layer ingestion propulsor is positioned in the tail section. The propulsor comprises a fan radially encased by a nacelle circumscribing the fuselage. The nacelle defines a leading edge line extending from a top dead center to a bottom dead center of the nacelle intersecting an axis of rotation of the fan at an angle no greater than seventy degrees.

An aircraft is disclosed having a boundary layer ingestion propulsor. The aircraft comprises an elongated fuselage extending between a nose section and a tail section. The fuselage has an upswept underside in the tail section. The boundary layer ingestion propulsor is positioned in the tail section. The propulsor comprises a fan radially encased by a nacelle circumscribing the fuselage. The nacelle defines a leading edge line extending from a top dead center to a bottom dead center of the nacelle intersecting an axis of rotation of the fan at an angle no greater than seventy degrees.

There is provided a vehicle configuration to reduce drag in a fluid stream. The vehicle configuration has a vehicle body. The vehicle configuration further has at least one auxiliary body coupled to, and positioned a distance from, the vehicle body, to form a channel between the at least one auxiliary body and the vehicle body. The vehicle configuration further has one or more exterior profiles of one or more of, the vehicle body and the at least one auxiliary body. The one or more exterior profiles are positioned in proximity to the channel, and are shaped with an aerodynamic shaping, so that the one or more exterior profiles each comprises one or more concave shape portions. When a fluid flow from the fluid stream flows through the channel, the drag resulting from fluid flow interactions between the vehicle body and the at least one auxiliary body is reduced.

There is provided a vehicle configuration to reduce drag in a fluid stream. The vehicle configuration has a vehicle body. The vehicle configuration further has at least one auxiliary body coupled to, and positioned a distance from, the vehicle body, to form a channel between the at least one auxiliary body and the vehicle body. The vehicle configuration further has one or more exterior profiles of one or more of, the vehicle body and the at least one auxiliary body. The one or more exterior profiles are positioned in proximity to the channel, and are shaped with an aerodynamic shaping, so that the one or more exterior profiles each comprises one or more concave shape portions. When a fluid flow from the fluid stream flows through the channel, the drag resulting from fluid flow interactions between the vehicle body and the at least one auxiliary body is reduced.

A battery assembly for an aircraft includes a cold plate having an upper planar member, a lower planar member, and at least one fluid channel positioned between the upper and lower planar members and configured to receive a cooling fluid. The battery assembly also includes an upper battery mounted to the upper planar member for transferring heat from the upper battery to the cooling fluid through the upper planar member. The battery assembly further includes a lower battery mounted to the lower planar member for transferring heat from the lower battery to the cooling fluid through the lower planar member.