CGull: a non-flapping seagull-inspired composite morphing drone

Introduction: Many avian species are well equipped for dynamic flight with flexible morphing wings and tails that optimize aerodynamic performance across various environmental conditions. As a result, imitating the shape-changing anatomical characteristics of birds can result in unmanned aerial vehicle (UAV) designs that outperform conventional fixed-wing UAVs in terms of flight performance. This rationale is the guiding principle behind the research on morphing aerospace structures. Methods: This work presents CGull, a bio-inspired, non-flapping UAV with wing- and tail-morphing capabilities. CGull’s target weight and size are based on the characteristics of the Great Black-Backed Gull (GBBG). A mathematical model was first developed in MachUpX to guide the selection of the design parameters for optimal performance at various morphing configurations. Only one morphing degree of freedom (DOF) was used in CGull’s wing, which bends the inner wing forward and the feathered outer wing backward, replicating the seagull’s wing deformation. A compact design of an actuation mechanism was proposed to control three DOFs in the tail: pitching, tilting, and feather expansion. Laminated composite structures were utilized in various components, such as the outer shell of the central body and the feathers. Computational fluid dynamics (CFD) and finite element analysis (FEA) simulations were performed to validate the design choices. Results: A proof-of-concept prototype was built, and various tests were performed to prove the effectiveness of the proposed design. Conclusions: The proposed bio-inspired morphing UAV design can replicate the GBBG’s non-flapping flight effectively. The selected composite materials and servomotors enabled us to achieve the design objectives.