Optimum Transverse Span Loads for Transport Category Aircraft

Abstract

This paper utilizes a higher-fidelity MDO approach to investigate the optimum transverse span load for transport category aircraft. The results developed here substantiate that, under most conditions, the classical minimum induced drag span load is the best choice for an aircraft. The method shown here allocates the span-wise distribution of thickness proportional to the local section lift coefficient of the equivalent 2D airfoil (Korn Equation), and twists the resulting wing to attain the traditional elliptical span load, as well as more “triangular” reduced root bending moment span loads. Both a traditional empirical and a rapid, computational structural optimization approach to wing design will be used to estimate structural weight. Two configurations will be examined: a large and small transonic transport aircraft (545,000-lb and 29,000-lb design weight). In each of these cases, the traditional elliptical span load was found to offer reduced fuel burns and reduced maximum take-off weight.