21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-2.3.2

VISCOUS DRAG OPTIMIZATION FOR A TRANSPORT AIRCRAFT MISSION ADAPTIVE WING

Martins A. L., Catalano F. M.
University of Sao Paulo, Brazil

Keywords: viscous drag, optimization, transport aircraft, adaptive wing

A direct optimization study has been performed to produce a preliminary evaluation of the potential benefits of a mission adaptive wing employing variable camber technology in typical jet transport aircraft missions, in terms of fuel efficiency increase directly obtainable from airfoil viscous (pressure + friction) drag reduction alone. A 2-D airfoil analysis approach has been adopted, associated with an proposed idealized variable camber mechanism based on elastic deformation and surface extension. Using a direct function optimization program coupled to a viscous-inviscid airfoil analysis routine, optimized variable camber configurations were obtained for several of the decreasing weight conditions a typical transport aircraft faces along a cruise mission leg, due to fuel consumption. Independent runs have been executed considering only trailing and both leading and trailing edge camber variation and, for each of them, an integrated range parameter has been obtained, proportional to the maximum possible aircraft range. Results indicate that range increases up to 7.03% over the base airfoil could be reached with camber variation in the trailing edge region only, a figure that rose up to 24.6% when leading edge adaptation was considered simultaneously. However, pressure distribution results indicate that the high leading edge curvatures required for that would probably not be allowed by efficient supercritical cruise requirements. Coincidentally, on the other hand, the trailing edge only approach seems to offer a better substract for supercritical cruise.

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