Design and Analysis of Winglets for Military Aircraft

Abstract : A study of the design and analysis on winglets for military Aircraft has been completed. The program consisted of investigating analytically winglet concepts for application to the KC-135 and C-141 designing and building winglets for an 0.035 and 0.070 scale model KC-135, and conducting a structural feasibility investigation of the winglet installation on the KC-135. The analysis of the winglets showed a 14% reduction in induced drag for the KC-135 and a 11% reduction for the C-141. The structural design study of the KC-135A winglet installation estimated a 592 lb weight increase. An 8.4% improvement was estimated in M(L/D) sub MAX and an 8.1% improvement in range factor for the KC- 135A. An 0.070 scale half span KC-135 wind tunnel model has been tested in the NASA 8 Ft Transonic Tunnel. Preliminary unpublished test data have substantiated the analytical procedures used by The Boeing Company to determine the aerodynamic characteristics and performance benefits from winglets on the KC-135 aircraft.