An airflow proximate to leading edges of a turbofan nacelle is ejected substantially normal to a fan face of the turbofan, creating suction proximate to the leading edge and mitigating flow separation proximate to the leading edge. One embodiment comprises a turbofan engine that includes a nacelle, a bypass fan, and a recirculation channel. The recirculation channel is disposed within the nacelle and has a recirculation channel inlet downstream of a leading edge of the bypass fan. The recirculation channel has one or more recirculation channel outlets upstream of the bypass fan that are proximate to a leading edge of a nacelle inlet, where the recirculation channel outlets redirect an airflow from the recirculation channel towards an inside edge of the nacelle inlet to mitigate flow separation at the leading edge of the nacelle inlet.

The disclosure is towards an inlet cowl for a turbine engine including a surface defining an inlet with a flow path and a method towards controlling the airflow in the flow path. The inlet cowl further includes an inlet lip and inner and outer barrels. The inlet lip confronts the inner barrel at a junction defining a gap.

A boundary layer ingestion engine includes a gas generator and a turbine fluidly connected to the gas generator. A fan is mechanically linked to the turbine via a shaft such that rotation of the turbine is translated to the fan. A boundary layer ingestion inlet is aligned with an expected boundary layer, such that the boundary layer ingestion inlet is configured to ingest fluid from a boundary layer during operation of the boundary layer ingestion engine.

An aircraft comprising a fuselage extending along a longitudinal axis between a fore section and an aft section, wings mounted to the fuselage, a tail unit mounted to the aft section of the fuselage, and a first propulsion unit and a second propulsion unit both mounted to the aft section of the fuselage in such a way that a first axis of rotation of the first propulsion unit and a second axis of rotation of the second propulsion unit both extend in a vertical center plane spanned by the longitudinal axis and a yaw axis. The provided centerline mounted double-engine aircraft allows for a simple manufacture, maintenance and retrofit of the engines, in that the first propulsion unit and/or the second propulsion unit are arranged outside the fuselage.

A tandem fan for a boundary layer ingestion engine is disclosed. In various embodiments, the tandem fan includes a fan disk configured for rotation about a longitudinal axis; a primary fan blade extending radially from the fan disk, the primary fan blade having a primary fan blade span; and a secondary fan blade extending radially from the fan disk, the secondary fan blade having a secondary fan blade span within about ninety percent to about one-hundred percent of the primary fan blade span.

An aircraft includes an airframe, an engine mounted to the airframe, and an engine inlet for receiving an ambient airflow and providing the ambient airflow to the engine. An amount of airflow provided to the engine inlet is controllable.

A gas turbine engine comprises a housing having an inlet leading to a fan rotor. A bypass door is mounted upstream of the inlet to the fan rotor, and is moveable away from a non-bypass position to a bypass position to selectively bypass boundary layer air vertically beneath the engine. An aircraft is also disclosed.

An inlet diffuser for a jet engine and methods for mixing boundary layers of air in compact inlet diffusers with high offset and high aspect ratio apertures are disclosed. The inlet diffuser includes an inlet diffuser body that includes elongate structures that are configured to allow a first portion of boundary layer air located between the elongate structures to flow within a channel, restrict the first portion of boundary layer air from flowing across either elongate structure, and allow a second portion of boundary layer air located outboard of the elongate structures to flow across the elongate structures and into a region of internal volume inward of the channel, wherein the second portion of boundary layer air is pushed away from the internal surface of the diffuser body by the elongate structures as the second portion of boundary layer air flows across the elongate structures in an inboard direction.

An aircraft including an aft-mounted boundary layer energisation system is shown. The system comprises a nacelle arranged around a tailcone of the aircraft which thereby defines a duct, the duct having, in axial flow series, an intake, a heat exchanger, and a nozzle, and no turbomachinery therein, whereby the system energises a boundary layer of the aircraft by means of Meredith effect.

An engine for mounting in or to an aircraft includes a stage of compression airfoils rotatable about a central axis; a casing surrounding the stage of compression airfoils and defining an inlet; and a low-distortion inlet assembly mounted within the inlet. The inlet assembly includes one or more structural members mounted at predetermined locations around a circumference of the central axis within the inlet, the predetermined locations defining an airflow distortion exceeding a predetermined threshold; and at least one airflow modifying element configured within the inlet so as to reduce airflow distortion entering the stage of compression airfoils.