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 wing droop leading edge apparatus and methods are described. An example aircraft includes a wing having a front spar and an outer skin covering the front spar. The outer skin includes a forward portion located forward of the front spar. The forward portion of the outer skin includes a leading edge movable between a neutral position and a drooped position deflected downward relative to the neutral position. The forward portion of the outer skin has a continuous outer mold line when the leading edge is in the drooped position.

Systems and processes that integrate thermoplastic and shape memory alloy materials to form an adaptive composite structure capable of changing its shape. For example, the adaptive composite structure may be designed to serve as a multifunctional adaptive wing flight control surface. Other applications for such adaptive composite structures include in variable area fan nozzles, winglets, fairings, elevators, rudders, or other aircraft components having an aerodynamic surface whose shape is preferably controllable. The material systems can be integrated by means of overbraiding (interwoven) with tows of both thermoplastic and shape memory alloy materials or separate layers of each material can be consolidated (e.g., using induction heating) to make a flight control surface that does not require separate actuation.

In a method for manufacturing prestressed shells having tunable bistability, in order to determine the appropriate prestress to be applied to the bistable structure/shell, it provides: clamping a shell by applying a predetermined curvature on a portion of its edge; defining a discrete shell model dependent on a small number of configuration parameters q_i, (i<5), by projecting the non-linear shell model of Marguerre-von Kármán onto an appropriate finite dimensional space so that the projection does not significantly alter the strain elastic energy; tracing the stability maps in the space of the design parameters by minimizing the discrete representation of the strain elastic energy E(q_i;p_i) thus obtained; and choosing the design parameters providing the prestress needed to obtain the desired response in terms of project requirements.

A morphing airfoil system includes an airfoil including a bulkhead and an airfoil body extending from the bulkhead, at least one inflatable/deflatable bladder positioned within the airfoil body, and a bladder pressurization mechanism configured for controlling pressurization of the at least one bladder. The system also includes one or more processors and a memory communicably coupled to the one or more processors and storing an airfoil control module including instructions that when executed by the processor(s) cause the processor(s) to control operation of the bladder pressurization mechanism to increase or decrease internal pressure in the at least one bladder to change a configuration of the airfoil.

A shock wave suppression device is configured to suppress a shock wave generated on a blade surface of a blade, the shock wave suppression device including a bump cover provided to follow the blade surface and deformable to protrude outward from the blade surface, and a displacing unit configured to displace the bump cover between a steady state to follow the blade surface and a deformed state to protrude outward from the blade surface. The bump cover has a curved shape in the deformed state configured to be a continuous surface from an upstream side to a downstream side in a flow direction of a fluid flowing through the blade surface.

A disclosed method reduces a wave drag on an airfoil traveling at a speed. At least a portion of the airfoil is configured to be selectively moveable between a first position and a second position. The first position is a neutral position, and the second position generates a shock wave near to the leading edge of the airfoil. The method includes the steps of maintaining the airfoil in the first position when the speed is less than a first limit and moving the airfoil to the second position when the speed is greater than a first limit.

A morphing airfoil system includes an airfoil having a bulkhead structured to form a leading edge of the airfoil. A first spool is rotatably coupled to the bulkhead, and a second spool is rotatably coupled to the bulkhead opposite the first spool. An airfoil skin has a first end secured to the first spool, a second end secured to the second spool, and a portion extending between the first and second spools to form an exterior surface of the airfoil. The airfoil skin is structured to be windable around the first and second spools such that a configuration of the airfoil is controllable by rotating at least one of the first spool and the second spool so as to wind a portion of the airfoil skin around, or unwind a portion of the airfoil skin from, the at least one of the first spool and the second spool.

A flight control system for an aircraft having a multi-functional flight control surface. The aircraft has at least one multi-functional flight control surface formed by a sequence of flaps. The shape of each multi-functional flight control surface may be configured by a flight control to simultaneously adjust a trajectory of the aircraft in two or more of a pitch direction, a roll direction, and a yaw direction. The flight control for operating said the multi-functional flight control surface responds to both pilot commands and machine-generated commands. The machine-generated commands configure the shape of the surface of each multi-functional flight control surface in real-time based, at least in part, upon a set of flight objectives comprising: (a) minimizing drag of the aircraft, (b) aeroelastic modal suppression for the aircraft, and (c) maneuver load alleviation in the aircraft.

A fluid actuator arrangement comprises a first cylinder housing including a first head member and a second head member; a first piston body is slidable arranged in said first cylinder housing; the first piston body divides the first cylinder housing interior into a first cylinder chamber and a second cylinder chamber, at least the first cylinder chamber is coupled to a fluid supply. The first piston body exhibits a first through-bore and a second through-bore that extend through the first piston body in an axial direction; a first piston rod is arranged slidable in the first through-bore and a second piston rod is arranged slidable in the second through-bore; and the first through-bore comprises a first engagement and disengagement device and the second through-bore comprises a second engagement and disengagement device, which are arranged for providing individual engagement or disengagement to or from the respective first and second piston rod.