Numerical and experimental investigation of aerodynamic optimization of an MQ-9 UAV wing using functionally graded materials

The present study addresses the challenge of improving the aerodynamic efficiency of the MQ-9 Reaper unmanned aerial vehicles (UAV) wing while maintaining its original mass. A parametric analysis was conducted using CFD simulation software to evaluate the effects of taper ratio, twist angle, and flight speed on aerodynamic performance across 125 case studies. The simulations were performed for taper ratios of 0.4, 0.55, 0.7, 0.85, and 1; twist angles of −4°, −2°, 0°, 2°, and 4°; and flight speeds of 5, 10, 15, 20, and 25 m/s. Based on these analyses, an algorithmic optimisation was applied to determine the optimal aerodynamic configuration, resulting in a taper ratio = 1, a twist angle = 4°, and a maximum speed = 25 m/s, which increased aerodynamic efficiency by approximately 39.5% compared to the original wing. To counteract the mass increase associated with the optimised geometry, Functionally Graded Materials (FGM) were applied, distributing material properties along the wing span while maintaining the original mass. The FGM approach was realised through Material Extrusion Additive Manufacturing (ME-AM). Both the original and FGM-optimised wing models were subsequently tested in a wind tunnel. The results demonstrate that combining aerodynamic optimisation, FGM, and AM enables significant performance improvements without increasing mass, providing a viable methodology for experimental UAV wing studies.