A fluid control system includes a deformable surface that covers a body in at least a first and second direction. The first direction is orthogonal to the second direction. The deformable surface includes a bottom side that faces the body and a top side that is opposite the bottom side. The fluid control system also includes at least one deformer between the deformable surface and the body. The at least one deformer is configured to modify a boundary layer of a fluid that is flowing over the deformable surface by selectively deforming the top side of the surface.

A Short Takeoff and Landing (STOL) aircraft has a fuselage with an axis and an engine providing thrust, a first aileron at an end of a first wing, a second aileron at an end of a second wing, a first slot having a length through the first wing proximate the first aileron, orthogonal to the axis; a second slot having a length through the second wing proximate the second aileron, orthogonal to the axis; a first electric motor in the first wing driving a first two-blade propeller in the first slot, a second electric motor in the second wing driving a second two-blade propeller in the second slot, and a control mechanism enabling a user to drive the first and second electric motors in a same rotary direction, to reverse the rotary direction, and to drive the first and second motors at a same rpm.

A method of using a split winglet includes providing an aircraft having a winglet attach fitting attaching a split winglet to a wing. The split winglet has an upper winglet and a lower winglet. The method additionally includes maintaining the winglet attach fitting and winglet at a first height relative to a fuselage when the aircraft is non-flying, and moving the winglet attach fitting and winglet to a second height relative to the fuselage when the aircraft is flying, the second height being higher than the first height.

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. Also, a wing with the wing tip device; an aircraft with the wing; a method of fitting, or retro-fitting, the wing tip device to a wing; a method of modifying an existing wing tip device; and a method of operating a wing with the wing tip device.

A locking pin associated with one of a fixed wing and a wing tip device, and a bush associated with the other of the fixed wing and wing tip device, the bush configured to receive the locking pin. The bush is located within a bush housing arranged to allow relative movement of the bush in the direction of a longitudinal axis of the locking pin when the locking pin is received within the bush.

A rotor blade for an aircraft includes first and second blade tips, a blade body, and a vortex-generating blade. The blade body has an end forming the first blade tip of the rotor blade and an airfoil section configured such that during rotation, pressure acting on a lower surface of the blade body is greater than pressure acting on an upper surface of the blade body. The vortex-generating blade is disposed at an end of the rotor blade and forms the second blade tip. The vortex-generating blade also has an airfoil section configured such that during rotation, pressure acting on a lower surface of the vortex-generating blade is smaller than pressure acting on an upper surface of the vortex-generating blade.

An ionic propulsion system for an aircraft having an airfoil includes a first conductor and a second conductor, the first conductor and the second conductor being disposed at least partially within the airfoil when not in use. The propulsion system includes an actuator for extending the first conductor and the second conductor from an end of the airfoil such that the first conductor and the second conductor are in the airstream of the aircraft, the first conductor being upstream of the second conductor in the airstream. The propulsion system includes a power supply for supplying current to the first conductor and the second conductor to ionize the air particles in the vicinity of the first conductor and the end of the airfoil to create a flow of the ionized particles from the first conductor toward the second conductor.

A flow control device on a structure such that strain in the structure is at least partially transferred to the flow control device is disclosed having at least two states, or shapes, separated by an elastic instability region. The flow control device is arranged to rapidly transition, or snap through, from the first state to the second state when strain in the structure exceeds an activation threshold of the flow control device. A spoiler on an aerofoil has a rest position where it is substantially flush with the low pressure surface and an activated position where it protrudes from the low pressure surface and modifies the airflow over that surface. The spoiler bends to move from the rest position to the activated position when the strain in the aerofoil crosses a threshold. The deployed spoiler reduces the lift on the aerofoil, acting to reduce the lift induced strain of the aerofoil to which the spoiler is attached.

Aircraft nacelles having adjustable chines are described. An example apparatus includes a multi-segment chine coupled to a nacelle. The multi-segment chine includes a first segment and a second segment. The first segment is oriented along a fore-aft direction. The first segment is rotatable relative to the nacelle about an axis of rotation. The axis of rotation is substantially perpendicular to a plane of the first segment defined by an outer mold line of the first segment. The second segment is fixedly coupled to the nacelle. The second segment is oriented along the fore-aft direction. The second segment is substantially coplanar with the first segment.

Aircraft nacelles having adjustable chines are described. An example apparatus includes a multi-segment chine coupled to a nacelle. The multi-segment chine includes a first segment and a second segment. The first segment is oriented along a fore-aft direction. The first segment is rotatable relative to the nacelle about an axis of rotation. The axis of rotation is substantially perpendicular to a plane of the first segment defined by an outer mold line of the first segment. The second segment is fixedly coupled to the nacelle. The second segment is oriented along the fore-aft direction. The second segment is substantially coplanar with the first segment.