Design and Verification of Large-Scaled Flapping Wings for High Altitude Environment

Large-scaled flapping wings for high altitude environments have great potential for border patrol and biodiversity exploration due to their high flight efficiency and concealment. In this paper, wind tunnel experimental techniques, neural network models, and flight tests are implemented to optimize and validate the performance of flapping wings. Numerical simulation methods were used to give recommendations for the flight state of the vehicle at high altitudes. From sea level to 4000 m altitude, the Reynolds number was subsequently reduced by 27.98%, and the time-averaged lift, drag, and pitching moment decreased by 33.31%, 33.08%, and 33.33%, respectively. A combination of planform with an increase in the internal area of the wing, six wing ribs, and linen film material was selected for its moderate stiffness to generate at least 1300 g of lift and considerable positive thrust, making it easier to reach a trim state. For high altitude environments, the vehicle needs to increase its flight speed and frequency to compensate for the loss of lift and drag due to reduced air density, but this is at the cost of power consumption, which results in reduced endurance, as verified by flight tests. Finally, this study aims to provide guidance on the design of large-scaled flapping wings for high-altitude environments.