Abstract: An airfoil member having an upper surface contoured to create lift. The lower airfoil surface has a lower forward surface portion which, in a rearward direction, curves concavely into an expanded convexly curved lower surface belly portion. This enables a primary load carrying member (e.g. a spar) to be located in the belly section and have a relatively greater depth, without unnecesary sacrifice of aerodynamic performance. In another embodiment, both the upper and lower surfaces of the airfoil are contoured with the expanded belly portion.

Abstract: A combined, liner retainer and seal for use with hydrofoils in which fluid foils have trailing control flaps, keyed together. The control flaps are hingedly engaged to the trailing end of the foils and are rotated on the hinge for control purposes. The flaps are segmented to form a series and in each pair a key extends from a driving flap into a keyway in a driven flap so that the flaps are rotatable together. There is an elastic liner within the keyways and into which the key fits, the liner serving to protect the metallic surfaces of the keys and keyways. The combined seal and retainer extends between the flaps from the trailing end of the foil to the trailing edge of the flaps and has openings through which a hinge pin and the key extends. The retainer is elastic and holds the liner within the keyway so as to prevent its dislodgment and destruction.

Abstract: A hinge assembly between a lifting foil (12) and an associated flap (14) wherein the flap (14) includes a series of sections (20, 22). In one embodiment, each section (20,22) may be rotatably mounted by a single hinge (24) to the foil (12) and interconnected by a coupling device (34) to an adjacent flap section. Additionally, a shear key coupling device (40) may be arranged between each pair of sections (20, 22) substantially extending to the trailing edge of each section (20, 22).