Abstract: An airfoil used in a ruddevator assembly for controlling movement of an aircraft refueling boom, where there are two airfoils (i.e. ruddevators) mounted to the boom, each at a dihedral angle of about 42.degree.. Each airfoil has an outboard section, which is an advanced technology cambered airfoil for high lift at transonic speeds, with a raked wing tip. The inboard portion of the airfoil has a forwardly extending strake-like member having a sharp leading edge which in planform comprises three sections. There is a curved forward edge section and two rearwardly extending edge sections, which in operation are positioned at high sweep angles. The side edge portions of the strake-like member create vortices which travel over the inboard portion of the airfoil to augment lift over a wide range of surface deflection of the airfoil (i.e., angle of attack).

Abstract: A wing extension or tip fin is disclosed wherein the tip fin is joined to an aircraft wing to form a nonplanar wing configuration which minimizes induced drag during both low speed and high speed operation of an aircraft. The tip fin which is of generally trapezoidal geometry, extends streamwise along the end of the aircraft wing and is canted to project upwardly and outwardly therefrom. Additionally, the tip fin is twisted to toe-out relative to the freestream direction with the angle of twist varying along the lower portion of the tip fin length. Viewed from the side, the tip fin has a sweep angle at least equal to the sweep angle of the aircraft wings with the leading edge of the tip fin intersecting the wing tip chord at a position aft of the wing leading edge. A strake which extends along the upper surface of the wing from the wing leading edge to the tip fin leading edge, forms a smooth transition between the wing and tip fin.

Abstract: A ruddevator assembly for controlling movement of an aircraft refueling boom, comprising two ruddevators mounted to the boom, each at a dihedral angle of about 42.degree.. Each ruddevator has an outboard section, which is an advanced technology cambered airfoil for high lift at transonic speeds, with a raked wing tip. The inboard portion of the airfoil has a forwardly extending strake-like member having a sharp leading edge which in planform comprises three sections. There is a curved forward edge section and two rearwardly extending edge sections, which in operation are positioned at high sweep angles. The side edge portions of the strake-like member create vortices which travel over the inboard portion of the ruddevator to augment lift over a wide range of surface deflection of the ruddevator (i.e., angle of attack).

Abstract: A tip fin or wing extension is disclosed wherein the tip fin is mountable to a conventional aircraft wing to form a nonplanar wing configuration which minimizes induced drag during both low speed and high speed operation of the aircraft. The tip fin is of generally trapezoidal geometry extending streamwise along the end of the aircraft wing and projecting vertically upward therefrom. The height of the tip fin and its cross sectional geometry are established to provide a substantial reduction in induced drag relative to that exhibited by the aircraft wing alone. Further, the tip fin is joined to the wing by a smoothly contoured upwardly extending arcuate region and the maximum thickness ratio of the tip fin airfoil section is established to minimize interference drag caused by the interaction of the tip fin within the wing flow field.