An inlet flow distortion control system employs a plurality of flow control devices forming at least one array integrated into an internal surface of the inlet. The at least one array extends over an azimuthal range relative to a normal flow axis of the inlet and has a plurality of circumferential rows spaced at increasing distance from a highlight of the inlet. A control system is operably connected to the flow control devices and adapted to activate flow control devices in selected subarrays of the array responsive to a predetermined flight condition.

An aircraft propulsion system with a drag reduction portion adapted to reduce skin friction on at least a portion of the external surface of an aircraft. The drag reduction portion may include an inlet to ingest airflow. The aircraft may also have an internally cooled electric motor adapted for use in an aerial vehicle. The motor may have its stator towards the center and have an external rotor. The rotor structure may be air cooled and may be a complex structure with an internal lattice adapted for airflow. The stator structure may be liquid cooled and may be a complex structure with an internal lattice adapted for liquid to flow through. A fluid pump may pump a liquid coolant through non-rotating portions of the motor stator and then through heat exchangers cooled in part by air which has flowed through the rotating portions of the motor rotor. The drag reduction portion and the cooled electric motor portion may share the same inlet.

An aircraft engine nacelle for coupling to a wing of an aircraft is disclosed having a fore end, and an aft end that is immoveable relative to the fore end. The aft end includes a major axis Mj and a minor axis Mi, and the nacelle is configured such the minor axis Mi is closer to vertical V than the major axis Mj when the nacelle is coupled to the wing and the aircraft is stationary on the ground. An aircraft system and an aircraft are disclosed each including the aircraft engine nacelle.

Methods, apparatus, systems, and articles of manufacture are to control air flow separation of an engine. An example turbofan includes a nacelle having an outer lip surface, an inner lip surface, a first opening and a second opening, the first opening coupled to a first region forward of a fan of the turbofan, the second opening coupled to a second region aft of the fan, the nacelle including a first pressure sensor coupled to the outer lip surface, a second pressure sensor coupled to the inner lip surface, and an actuator, and a conduit coupled to the actuator, the conduit configured to have a first end and a second end, the first end coupled to the first opening, the second end coupled to the second opening.

An airfoil is provided defining a spanwise direction, a chordwise direction, a root end, a tip end, a leading edge end, and a trailing edge end. The airfoil includes: a leading edge extending from the leading edge end; a body extending along the spanwise direction between the root end and the tip end, the body including a plurality of cavity walls defining a plurality of cavities, each of the plurality of cavities having an inlet located at the leading edge; and a porous face sheet positioned on at least one inlet of the plurality of cavities.

A turbine engine including a fan, a nacelle circumscribing at least the fan, a compressor section downstream of the fan, and a conduit defined, at least in part, by the nacelle. The conduit includes a first opening at the compressor section, a second opening downstream of the fan and upstream of the compressor section, and a third opening upstream of the fan. Pressure sensors coupled to the nacelle are communicatively coupled to at least one actuator. The at least one actuator can adjust airflow between the first opening and the second opening, or between the first opening and the third opening. The pressure sensors can provide outputs for generating commands that control the at least one actuator.

An aircraft including a fuselage and an aft engine is provided. The fuselage extends from a forward end of the aircraft towards an aft end of the aircraft. The aft engine is mounted to the fuselage proximate the aft end of the aircraft and includes a fan and a nacelle. The fan is rotatable about a central axis of the aft engine and includes a plurality of fan blades. The nacelle of the aft engine surrounds the plurality of fan blades and defines a bottom portion having a forward end. Additionally, the nacelle defines a curved surface at the forward end of the bottom portion, the curved surface including a reference point where the curved surface defines the smallest radius of curvature. The nacelle further defines a normal reference line extending normal from the reference point. The normal reference line defines an angle with the central axis of the aft engine greater than zero to, e.g., allow for a maximum amount of airflow into the aft engine.

An assembly is provided for active laminar flow control. This assembly includes a panel, which panel includes an outer skin, an inner skin and a plurality of plenums between the outer skin and the inner skin. Each of the plurality of plenums is fluidly coupled with a respective array of perforations through the outer skin. The panel is constructed from fiber-reinforced composite material.

An active laminar flow control arrangement may comprise an outer skin having an inner surface, an outer surface, and a perforated area, and a panel coupled to the inner surface. The panel may comprise a longitudinal wall, a sidewall extending from the longitudinal wall, a ridge intersecting the sidewall, a cavity disposed in the panel and at least partially defined by the sidewall and the longitudinal wall, and a division wall disposed in the cavity and extending from the longitudinal wall, wherein the division wall divides the cavity into a first plenum and a second plenum. The longitudinal wall, the sidewall, the ridge, and the division wall may comprise a single, monolithic piece.

A hybrid electric gas turbine propulsion system may comprise: a first propulsion system, a second propulsion system, and a third propulsion system. The first propulsion system may comprise a first fan, a first turbine, a first compressor, and a first electric motor, the first fan operably coupled to the first turbine and the first compressor by a first shaft, the first shaft coupled to the first electric motor, the first shaft configured to be disposed radially inward of a fuselage of an aircraft. The second propulsion system and the third propulsion system may be in accordance with the first propulsion system. The hybrid electric gas turbine propulsion system may be symmetric about a vertical plane extending through a neutral aerodynamic axis.