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.

Provided are wingtip torque boxes and methods of fabricating such boxes using friction stir welding. Specifically, a wingtip torque box may be formed by friction stir welding two monolithic clamshells along their respective spars thereby forming a new monolithic structure. Use of the friction stir welding and monolithic clamshells simplifies the overall fabrication process and yields a robust wingtip torque box that can be bolted on or otherwise attached to an aircraft wing. The wingtip torque box may include internal grid stiffeners and/or external stiffeners that may be also monolithic with other components of the box. For example, the stiffeners may be machined in spars or skin portions of the clamshells during fabrication of clamshells. The wingtip torque box may have a continuous cavity extending between the ends and, in some embodiments, between spars of the box and providing access for performing various operations inside the box.

An aircraft includes a fuselage, a wing attached thereto, a wing tip device attached to a wing end of the wing (2), a wing-like element having a wing root, a wing leading edge and a wing trailing edge, and a torque control device having a rotatable interface means. The torque control device is adapted for rotatably supporting the wing root of the wing-like element on the interface means about a rotational axis extending from the interface means into the wing-like element and to limit the degree of rotation depending on a torque introduced into the interface means by the wing-like element. The wing-like element is adapted to induce a rotation around the rotational axis in an air flow. The wing root is coupled with the wing tip device, the wing or the fuselage through the torque control device such that the leading edge extends into an airflow surrounding the aircraft.

A propeller system combines innovative strategies to create a new methodology to reduce propeller or rotor noise. The propeller is specifically aimed for ultra-quiet electrically powered aircraft for use in high proximity aviation, but its low-noise advantages will extend to other purposes. The propeller blade includes geometries, along with size and operational limitations that minimize rotational and vortex noise, vibration and span-wise air flow on the blade. To further reduce noise, the propeller provides greater relative thrust on the inboard portions of the blade than do conventional propellers and provides less than conventional relative thrust including negative thrust at the outermost portions of the blade. The propeller blade includes stepped changes in shape at calculated intervals that can reduce resonant blade vibrations and their resultant noise. This ultra-quiet propeller design can also be used for quieting hovercraft, drones, surveillance aircraft, indoor fans, wind tunnels and other applications.

A wing tip device for fixing to the outboard end of a wing, the wing defining a wing plane, the wing tip device comprising: an upper wing-like element projecting upwardly with respect to the wing plane and having a trailing edge; and a lower wing-like element fixed with respect to the upper wing-like element and having a root chord and a trailing edge, the lower wing-like element root chord intersecting with the upper wing-like element, and the lower wing-like element projecting downwardly from the intersection, wherein the upper wing-like element is larger than the lower wing-like element and the trailing edge of the lower wing-like element is adjacent the trailing edge of the upper wing-like element at the intersection, and wherein an included angle between the upper and lower wing-like elements at the intersection is less than, or equal to, 160 degrees.

An aircraft wing is disclosed having a root end, a tip end, a span extending between the root end and the tip end, a leading edge, a trailing edge and a chord extending between the leading edge and the trailing edge, and including a main fixed wing portion having an inboard portion adjacent the root end, and an outboard portion adjacent the tip end. A wing tip device attached to the tip end of the wing; and a movable flight control surface connected at the outboard portion of the main fixed wing portion and having a leading edge, a trailing edge and a chord extending between the leading edge and the trailing edge. A ratio of the local chord length of the movable flight control surface to the local chord length of the wing varies in the spanwise direction.

The invention relates to a wing with two winglets (9-12) and a respective airplane. An upstream winglet (9, 11) broadens a region of inclined airflow and a downstream winglet (10, 12) produces a thrust contribution therein.

Example active flow control systems and methods for aircraft are described herein. An example active flow control system includes a plurality of nozzles arranged in an array across a surface of an aircraft. The nozzles are oriented to eject air across the surface to reduce airflow separation. The active flow control system also includes an air source coupled to the nozzles and a controller to activate the nozzles to eject air from the air source in sequence from outboard to inboard and then from inboard to outboard to create a wave of air moving from outboard to inboard and then from inboard to outboard across the surface.

An airplane including a wing and a wing tip attached to an end of the wing. The wing has a wing leading edge and a wing trailing edge in a wing chord plane. The wing tip includes a winglet and a ventral fin. The winglet has a winglet leading edge continuously transitioning from the wing leading edge, and a winglet trailing edge continuously transitioning from the wing trailing edge. The winglet leading edge may be swept rearward. The winglet includes an adapter section attached to the end of the wing, a transition section attached to the adapter section, a blade section attached to the transition section, the blade section extending above the wing chord plane, and a first tip section attached to the blade section. The ventral fin may be coupled to the winglet at an attachment location adjacent the transition section, and extends below the wing chord plane.

The invention concerns an aircraft propulsion system having an engine core within which fuel is combusted to produce an exhaust containing water produced from the combustion of fuel, at least one propulsive fan for generating a mass flow of air which mixes with the exhaust of the engine core, and one or more sensor arranged to sense a condition indicative of vapor trail formation by the exhaust flow from the engine; and a controller arranged to control the ratio of the mass flow of water in the exhaust to the mass flow of air propulsed by the propulsive fan such that the ratio is reduced upon sensing of said condition by the one or more sensor.