Embodiments of the present disclosure include a curved planar wingtip for a straight wing and a curved planar wingtip for a swept wing of an aircraft. The curved planar wingtips include a member that extends from the end of the wing in a direction aft of the wing trailing edge while remaining substantially planar with the wing. The curved planar wingtips curve continuously from leading and trailing edges of the wing to form a tip located aft of the wing. Other embodiments of the curved planar wingtip are configured for a horizontal or vertical tail. Yet another embodiment includes a curved wingtip that extends aft of a trailing edge of the wing by a distance greater than the curved wingtip extends above a top surface of the wing.

A structure adapted to traverse a fluid environment includes an elongate body having a root, a wingtip, a leading edge and a trailing edge; and a rigid winglet associated with the wingtip and having a winglet body extending substantially normal to one of a suction side and a pressure side of the elongate body to a termination point that is rearward of the trailing edge. In an embodiment, the structure is a rotor blade that may be incorporated into a wind turbine.

A cross-flow fan includes a plurality of fan blades provided to be circumferentially spaced apart from each other. The fan blade has an inner edge portion arranged on the radially inner side to/from which air flows in/out, and an outer edge portion arranged on the radially outer side to/from which air flows in/out. Fan blade has a blade surface extending between the inner edge portion and the outer edge portion. The blade surface includes a pressure surface arranged on the rotation direction side of the cross-flow fan and a suction surface arranged on the back side of the pressure surface. When cut along a plane orthogonal to the rotation axis of the cross-flow fan, the fan blade has a blade cross-sectional shape in which a concave portion concave from the pressure surface is formed.

A cross-flow fan includes a plurality of fan blades provided to be circumferentially spaced apart from each other. The fan blade has an inner edge portion arranged on the radially inner side to/from which air flows in/out, and an outer edge portion arranged on the radially outer side to/from which air flows in/out. Fan blade has a blade surface extending between the inner edge portion and the outer edge portion. The blade surface includes a pressure surface arranged on the rotation direction side of the cross-flow fan and a suction surface arranged on the back side of the pressure surface. When cut along a plane orthogonal to the rotation axis of the cross-flow fan, the fan blade has a blade cross-sectional shape in which a concave portion concave from the pressure surface is formed.

An airplane wing assembly includes a wing, a winglet and a connection element. The wing has a wing box. The wing box is located at a wing tip of the wing and the winglet is connected with the wing by the wing box. The connection element includes a butt joint rib, which is assembled with the wing box, and a center connection, which is assembled with the winglet. The butt joint rib has a first shearing pin hole and a second shearing pin hole, into which are press fitted a corresponding first and a second shearing pin respectively to form interference fit. The center connector has a first sleeve hole and a second sleeve hole.

An aerodynamic structure for use on an upper surface of an aircraft wing is disclosed. The wing includes a slat operable between a stowed configuration in which the slat is stowed in a slat recess of the wing, and a deployed configuration in which the slat extends out of the slat recess. When the slat is in the deployed configuration, an end face of the slat recess is exposed, the end face intersecting with the upper surface of the wing at a recess edge. The aerodynamic structure, adjacent to the recess edge, has a volume shaped to encourage air flowing over the recess edge onto the upper surface during flight, to remain attached.

Embodiments of methods and apparatus for close formation flight are provided herein. In some embodiments, a method of operating aircraft for flight in close formation includes establishing a communication link between a first aircraft and a second aircraft, assigning to at least one of the first aircraft or the second aircraft, via the communication link, initial positions relative to one another in the close formation, providing flight control input for aligning the first and second aircraft in their respective initial positions, tracking, by at least one aircraft in the close formation, at least one vortex-generated by at least one other aircraft in the close formation, and based on the tracking, providing flight control input to adjust a relative position between the first aircraft and the second aircraft.

An active winglet includes a body portion substantially parallel to a wing of an aircraft, as if it were an extension of the wing. The body portion is attachable to an aircraft wing and includes a controllable airflow modification device coupled thereto. By virtue of having a controllable airflow modification device, the winglet is capable of adjusting a control surface of the controllable airflow modification device in response to in-flight conditions, to reduce wing loads, increase range, and/or increase efficiency.

A vortex generator system has at least two vortex generators protrudable from an outer mold line of a vehicle surface at a location upstream of a cavity leading edge of a cavity in the vehicle surface. The vortex generators are spaced apart from each other and oriented such that the vortex generator aft ends are nearer to each than the vortex generator forward ends. The vortex generator lengthwise direction of each one of the vortex generators is oriented at a vortex generator directional angle relative to a direction of an airflow. The vortex generators are configured to generate a pair of counter-rotating vortices when the airflow passes over through or over the vortex generators. The counter-rotating vortices interact to produce a downwash of air away from the cavity that urges the store away from the vehicle as the store exits the cavity.

A swept gradient air boundary layer diverter for an aircraft. The aircraft includes a fuselage and an air inlet for an engine of the aircraft, where the air inlet includes a cowl at a leading edge of the inlet. The diverter includes a V-shaped ramp portion formed in the fuselage in an area proximate to and in front of the cowl where the ramp portion extends downward away from an outer surface of the fuselage towards an inside of the aircraft. The diverter also includes a V-shaped trough portion formed into the fuselage and being positioned adjacent to and integral with the ramp portion between the ramp portion and the air inlet. Air flowing over the fuselage towards the cowl is expanded and compressed by the ramp portion and the trough portion so as to create pressure gradients that generate vortices to redirect boundary layer airflow around the air inlet.