SMART Hawk: A Shape-Morphing Artificial Red-Tailed Hawk

Introduction: The red-tailed hawk (RTH) is a remarkable soaring raptor with a broad wingspan that grants it impressive aerodynamic efficiency, allowing for effortless gliding and rapid transitions into high-speed dives for instant prey capture. These capabilities make the RTH an ideal biological model for developing a feathered, morphing drone that is capable of achieving glider-like aerodynamic efficiency while retaining the maneuverability of quadcopters. Methods: This work presents “SMART Hawk,” a biomimetic, non-flapping Unmanned Aerial Vehicle (UAV) with wing- and tail-morphing capabilities. SMART Hawk’s target weight and size are based on the physical characteristics of a female RTH. A mathematical model was first developed in MachUpX to guide the selection of the design parameters for optimal aerodynamic performance at various morphing configurations. SMART Hawk’s wing incorporates artificial composite feathers that are distributed along the wingspan and connected to a linkage mechanism modeled after avian wing bones, allowing the wing to sweep in a way that mimics the natural deformation of the hawk’s wing natural. The wing’s airfoil profile was extracted from the cross-section of the RTH obtained through 3D scanning of an RTH cadaver. A compact tail mechanism was designed to actuate three degrees of freedom: pitching, tilting, and feather expansion. Composite shells, balsa wood, and 3D-printed ASA plastic were used strategically for the structural and load-bearing components. Propulsion was achieved via a single electric motor located at the nose of the fuselage. Computational fluid dynamics (CFD) and finite element analysis (FEA) simulations were performed to validate the design of all UAV components. Results: A proof-of-concept prototype was built and flight tests were performed to prove the effectiveness of the proposed design. Conclusions: The proposed biomimetic morphing UAV design can replicate the aerodynamic qualities of the RTH. The selected materials and servomotors enabled the achievement of the design objectives.