US Patent 7537270 Air foil

An airfoil which has one or more laminar flow control features to enhance the aerodynamic performance of bluff body vehicles such as buses and truck-tractor trailer rigs. Theses features include a combination of curved and tapered airfoil surfaces, air ejectors or other vacuum producing devices that reduces the air drag over the moving surface. The basic form of structure is a hollow curved and tapered airfoil surface with its base mounted against the rear vehicle wall with hinges such that the airfoil can be folded back against the side of the vehicle.