Abstract: 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.

Abstract: A coupling device for supporting a first wing section against a second wing section of an aircraft, and configured for passive flight load alleviation includes a housing including a chamber including a first portion and a second portion and filled with a fluid, a piston device movably arranged in the chamber and separating the first portion from the second portion in a fluid tight manner, a first fluid pathway connecting the first portion to the second portion, a first pressure relief valve arranged in the first fluid pathway and blocking the first fluid pathway, if the pressure in the second portion is smaller than a first relief pressure and opening the first fluid pathway, if the pressure in the second portion is greater than the first relief pressure. In addition, the coupling device can be used to actuate the second wing section against the first wing section.

Abstract: There is disclosed an aircraft wing rib comprising a structural rib section to which a wing skin can be attached; and a suction conduit to which, in use, a negative pressure can be applied so as to cause air to be drawn through suction holes provided in the outer surface of the wing skin. There is also disclosed an aircraft wing including such a wing rib.

Abstract: 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.

Abstract: For establishment of a laminar attachment line flow, an aircraft wing includes a leading edge including an attachment line, where air impinging on the region flows in a boundary layer spanwise along the leading edge. The leading edge and the attachment line are at least partially formed at first and second slats. The second slat is located adjacent to the first slat in the downstream direction of the attachment line flow, so that the leading edge includes a slat-to-slat junction, where a slat cavity is formed. A duct has a duct entrance at the slat-to-slat junction for receiving spanwise flow along the leading edge of the wing. The duct entrance extends around the leading edge and over the range of positions of the attachment line at the slat-to-slat junction.

Abstract: A coupling device for supporting a first wing section against a second wing section of an aircraft, and configured for passive flight load alleviation includes a housing including a chamber including a first portion and a second portion and filled with a fluid, a piston device movably arranged in the chamber and separating the first portion from the second portion in a fluid tight manner, a first fluid pathway connecting the first portion to the second portion, a first pressure relief valve arranged in the first fluid pathway and blocking the first fluid pathway, if the pressure in the second portion is smaller than a first relief pressure and opening the first fluid pathway, if the pressure in the second portion is greater than the first relief pressure. In addition, the coupling device can be used to actuate the second wing section against the first wing section.

Abstract: There is disclosed an aircraft wing rib comprising a structural rib section to which a wing skin can be attached; and a suction conduit to which, in use, a negative pressure can be applied so as to cause air to be drawn through suction holes provided in the outer surface of the wing skin. There is also disclosed an aircraft wing including such a wing rib.

Abstract: Modern aircraft wings generally have a lower surface the rear part of which is concave over at least some of its length, for additional lift. Sometimes it is desirable to reduce the wing lift, for instance during turbulence. To this end the wing 1 has, located at least partly in or forward of this concave part and forward of the trailing edge, a spoiler device such as a deployable spoiler 20 operable to change between a configuration in which the surface is uninterrupted and one in which the device separates flow, so as to reduce local lift over the concave portion. An actuator 26 can be provided for deploying the spoiler, and an upper spoiler 40 can also be present, operated by the same or a separate actuator. Alternatively the spoiler device can include a flexible or deforming material 120 operable to protrude from the wing surface.

Abstract: For establishment of a laminar attachment line flow, an aircraft wing includes a leading edge including an attachment line, where air impinging on the region flows in a boundary layer spanwise along the leading edge. The leading edge and the attachment line are at least partially formed at first and second slats. The second slat is located adjacent to the first slat in the downstream direction of the attachment line flow, so that the leading edge includes a slat-to-slat junction, where a slat cavity is formed. A duct has a duct entrance at the slat-to-slat junction for receiving spanwise flow along the leading edge of the wing. The duct entrance extends around the leading edge and over the range of positions of the attachment line at the slat-to-slat junction.