Abstract: A system for selectively controlling deformation. The system includes a first mechanism for resisting deformation about an axis of an accompanying fluid foil. A second mechanism, in communication with the first mechanism, enables deformation along the axis and/or at an angle to the axis. In more a specific embodiment, the axis is a lengthwise axis of the fluid foil, which is a transformable airfoil, and the system includes a bellows device that is approximately concentric with the axis. The bellows device is supported by first base structure at one end and a second base structure at another end. The deformation at an angle to the first axis includes shear deformation or bending deformation. The deformation along the axis includes extension or strain deformation. The deformation about the axis includes torsion deformation.

Abstract: An adjustable fluid foil. The fluid foil includes one or more adjustable spars that are connected to one or more adjustable ribs. A deformable surface substantially houses the one or more adjustable spars and ribs. In a specific embodiment, the deformable surface is sufficient to enable changes in one or more span-wise fluid foil geometries in response to adjusting of the frame. In the specific embodiment, the one or more adjustable spars and ribs are substantially coplanar, sharing a plane that is approximately parallel to a surface area of the fluid foil. The one or more adjustable spars and ribs include a mechanism for adjusting the position and/or a mechanism for adjusting the size of one or more adjustable spars and ribs. In one embodiment, the one or more adjustable spars and ribs are pivotally interconnected to facilitate adjustments in relative angles formed therebetween.