Design, aerodynamic analysis and test flight of a bat-inspired tailless flapping wing unmanned aerial vehicle

Abstract

This paper provided a design of bat-inspired tailless flapping wing unmanned aerial vehicle (UAV) based on the biological data of the large flying fox. The wing span of the UAV is 1.68 m and the total mass is 289 g. Aerodynamic characteristics at design cruise speed were analyzed based on the computational fluid dynamics (CFD) method. Selected variables within the analysis are angle of attack and flapping frequency. Prototype of the UAV has been manufactured follows the design parameters. The flapping mechanism employed a 2-DOFs revolute-spherical-spherical-revolute (RSSR) system to reflect the flapping attitude of bats. An outdoor test flight was then processed with the manufactured prototype. Onboard flight data recorder (FDR) was equipped to conserve the flight data such as flight speed, pitching angle and the three-dimensional position of the flight. It is shown by the data obtained from the FDR that the bat-inspired UAV is able to achieve the stable cruise with circular route at flight speed 6.8 m/s with the average angle of attack 4.1 degrees and flapping frequency 3.7 Hz. Test flight shows that the UAV is able to provide a 5 minutes free outdoor cruise with the equipped Li-Po battery. Research proves that the tailless configuration flapping wing UAV is able to sustain a stable flight, which provides a new design possibility for future researches.