A Preliminary Design Method for High Aspect Ratio Wings Including Load Alleviation Devices

Most preliminary design methods, which are often based on regressions of actual aircraft measurements, do not capture how unconventional aircraft designs - including wings with load alleviation technology - could affect performance. Therefore, a physics based aero-structural preliminary design tool has been developed to predict the mass and drag of wings. The approach was validated by using it to analyse existing civil aircraft, and performs well in comparison to standard approaches. This method also allows physics-based understanding of high aspect ratio wings, and to demonstrate its flexibility it was used to perform an aspect ratio study. Three scenarios were considered: a normal cantilever wing, a strut-braced wing, and a wing with a semi-aeroelastic hinged wing-tip. The tool was integrated into Pacelab APD - a commercial whole aircraft sizing software - and it was found that, even at an early design stage, considering the impact of wing design on the rest of the aircraft is essential. For the baseline aircraft considered, both load alleviation devices were shown to reduce wing mass by 20-25 % when aspect ratio was increased to 20; design mission fuel burn was also reduced. The method presented here is an improvement on traditional empirical approaches, and is particularly suited for conceptual and preliminary design of unconventional wings.