Considerations about Wingtip Devices Design of Transport Airplane

Bento S. Mattos, Paulo J. Komatsu (Technological Institute of Aeronautics)

CHALLENGE - There is a constant need to reduce the required fuel burn of commercial aircraft, which can be achieved with the reduction of drag by optimizing wings and winglets. Two winglet optimization studies were carried out for a 70-seat airliner: one for wing/winglets optimized for cruise and field performance, and the other for wings without winglets.

SOLUTION - In the second optimization study, the methodology for winglet and raked wing design was developed using modeFRONTIER's genetic algorithm MOGA-II. Objectives were the maximization of the wing-body-winglet maximum lift coefficient and maximization of the lift-to-drag ratio at a desired cruise condition. Design variables are wing planform parameters, wing airfoil shape parameters, and wing planform characteristics. The methodology modeled airfoil shapes of root, break station, and tip. The Pareto frontier for configuration with winglets lie above the one obtained from the optimization for wing-body alone, justifying the adoption of winglets from an aerodynamic point of view.

BENEFITS - Results from the optimization method carried out in modeFRONTIER show that configurations without winglets experience a considerable drop of the lift-to-drag ratio when compared to their counterpart with winglets. Solution 6772, shown above, presents the highest lift-to-drag ratio, 25.42 at cruise condition.