The rotary airfoil 100 defines a cross section and a span, wherein the cross section is a function of the point along the span (e.g., spanwise point) and defines an upper surface and a lower surface at each spanwise point. The rotary airfoil 100 also defines, at a cross section, a lift coefficient (C.sub.L) that is a function of the angle of attack at which the airfoil is rotated through the air. The system can optionally include: a rotor hub to mount the rotary airfoil, a tilt mechanism to pivot the rotary airfoil between a forward configuration and a hover configuration, and a pitching mechanism to change the angle of attack of the rotary airfoil 100.

The invention discloses an aircraft generating a larger thrust and lift by fluid continuity. First open channels used to extend fluid paths are formed in front parts and/or middle parts of windward sides of wings of the aircraft and extend from sides, close to the fuselage, of the wings to sides, away from the fuselage, of the wings, and the first open channels are concave channels or convex channels, so that a pressure difference in a direction identical with a moving direction is generated from back to front due to different flow speeds of fluid flowing over the windward sides of the wings in a lengthwise direction and a widthwise direction to reduce fluid resistance, and a larger pressure difference and lift are generated due to different flow speeds on the windward sides and leeward sides of the wings.

An aircraft wing has an upper surface element and a first actuator powered mechanism for varying the shape of the surface element which includes: an upstream segment SEG.sub.1, a downstream segment SEG.sub.2, an interconnecting segment SEG.sub.3 interconnecting a downstream edge of SEG.sub.1 with an upstream edge of SEG.sub.2, wherein the interconnecting segment SEG.sub.3 extends along the whole or at least a major part of the downstream edge of SEG.sub.1 and the whole or at least a major part of the upstream edge of SEG.sub.2, and a link element LNK interconnecting an upstream edge of SEG.sub.1 with an upper surface of the aircraft wing, and the first mechanism interconnecting a contact C1 on a lower side of the upper surface element with a contact C2 on an inner structure of the airfoil. The first mechanism controls the shape of the upper surface element by controlling the distance between C1 and C2.

In one embodiment, an airfoil includes a first end and a second end opposite the first end. The airfoil also includes a first side and a second side opposite the first side. The airfoil includes a continuous panel coupled to the first side of the airfoil. The continuous panel includes a first edge having a first uneven edge pattern. The first edge has at least four vertices disposed thereon. The continuous panel extends from the first end of the airfoil to a second end of the airfoil.

A fixed wing aircraft has a wing with an aerofoil cross-section defining an upper and lower geometric surfaces which meet at a geometric leading edge of the wing. The wing has an upper and lower aerodynamic surfaces while in flight. The upper aerodynamic surface and the lower aerodynamic surface meet at an aerodynamic leading edge at the intersection with an attachment line dividing the air that passes over the upper aerodynamic surface from the air that passes over the lower aerodynamic surface. The lower geometric surface adjacent the geometric leading edge has a roughness strip with a step height of at least 50 microns over the lower geometric surface. The roughness strip is located on the lower aerodynamic surface of the wing when the aircraft is flown at a load factor of 1 g and is located on the upper aerodynamic surface when the load factor is above 1.2 g.

A flow interrupting device may cause a flow to separate from a wingtip device at a desired angle of attack. The flow interrupting device may be coupled to a leading edge of a wingtip device where a flow disruptor may be configured to alleviate a load on the wingtip device. The flow disrupter may comprise an edge that extends into a boundary layer at a threshold angle of attack that may disrupt the boundary layer and cause a flow to separate from the wingtip device. This separated flow may reduce stresses experienced by the wingtip device and wing during various flight conditions where a transverse flow is encountered.

An aerofoil component defines an in use leading edge and a trailing edge. The leading edge has at least one serration defining an apex and a nadir. The leading edge has a generally chordwise extending slot located at the nadir of each serration.

Airfoil and hydrofoils systems with structures having a surface texture defined by fractal geometries are described. Raised portions or fractal bumps can be included on the surfaces, forming a surface texture. The surface textures can be defined by two-dimensional fractal shapes, partial two-dimensional fractal shapes, non-contiguous fractal shapes, three-dimensional fractal objects, and partial three-dimensional fractal objects. The surfaces can include indents having fractal geometries. The indents can have varying depths and can be bordered by other indents, or bumps, or smooth portions of the airfoil or hydrofoil structure. The fractal surface textures can reduce vortices inherent from airfoil and hydrofoil structures. The roughness and distribution of the fractal surface textures reduce the vortices, improving laminar flow characteristics and at the same time reducing drag. The systems are passive and do not require applied power.

An aerodynamic element is provided with at least one set of protruding elements, each of the protruding elements is produced in the form of an elongate and profiled rib projecting from a surface of the aerodynamic element. The protruding elements are arranged at the surface of the aerodynamic element, one beside the other, being oriented substantially parallel to one another so that each of them generates a vortex, the set of vortices thus generated making it possible to reduce crossflow instability.

A multirotor aircraft with an airframe and at least one wing that is mounted to the airframe, the at least one wing being provided with at least four thrust producing units that are arranged in spanwise direction of the at least one wing, wherein each one of the at least four thrust producing units comprises at least one rotor assembly that is accommodated in an associated shrouding, the associated shrouding being integrated into the at least one wing, wherein the associated shrouding defines an air duct that is axially delimited by an air inlet region and an air outlet region, wherein the air inlet region exhibits in circumferential direction of the air duct at least two different aerodynamic profiles.