Considerations about wingtip devices design of transport airplane

Abstract

© 2015, American Institute of Aeronautics and Astronautics Inc, AIAA. All rigths reserved.From the beginning of aviation designers are searching for methods and technologies for reducing the required fuel burn of commercial aircraft. Wingtip devices in special winglets offer a way of significative drag reduction for transport airplanes. Winglet alongside with tip tanks, raked wingtips, aligned fans belong to this class of wingtip devices. Although winglets are targeted to induced drag reduction their effects can be extended to wave and zero-lift drag as well. Induced drag alone is responsible for 30-40% of the overall drag of a transport airplane at long-range cruise condition and for considerably downgrading the climb performance of fixed-wing aircraft. Better investigation in this field employing CFD tools and extensive wind-tunnel testing has allowed the rising of efficient winglet designs in recent times. Several of newly designed aircraft configurations embody winglets and many older ones are being retrofitted. However, there are discussions concerning the best cost/benefit of reducing induced drag of a transport plane with wingtip devices. Another big issue is the associated penalties to the configuration caused by winglets when compared to a simple wingtip extension. This paper addresses some of these issues based on the expertise obtained designing winglets for several airplane configurations, ranging from a business jet and a twinjet airliner for 70 passengers to an AEW&C military airplane.

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