Wing weight estimation in conceptual design: a method for strut-braced wings considering static aeroelastic effects

Abstract

This paper presents a method for the wing weight estimation of strut-braced wing aircraft in conceptual design. The method is simple to implement while still capturing important effects for early design estimates. Static aeroelastic loads, aeroelastic divergence and aileron reversal criteria are calculated directly with small matrices suitable for implementation in spreadsheet software. Maneuver, gust and ground cases are considered. A direct non-iterative method is used for the strut and wing internal loads calculation. The wing and strut load-carrying structures are sized with analytical box-beam equations for strength, buckling and fatigue criteria. Aluminum or composite laminates can be considered. Semi-empirical methods are presented for non-optimal mass components and the secondary structure. The aeroelastic effects and strut reaction estimations are compared for a wide range of design parameters with Nastran validating the proposed method. The weight estimations are verified with conventional aircraft data and strut-braced wing studies available in the literature, showing good accuracy. Design trade studies are presented illustrating typical applications of the method. A potential to reduce the wing mass in about 18 % or to increase the aspect ratio from 10 to 16 compared to a cantilever wing is identified.