Aerodynamic characteristics of a novel catapult launched morphing tandem-wing unmanned aerial vehicle

A novel morphing unmanned aerial vehicle with tandem-wing configuration could fold into a tubular catapult and deploy the four airfoils after launching. Because of the rapid deploying process, the aerodynamic characteristics will become largely different. Numerically investigating the aerodynamic characteristics at low Reynolds numbers (Re < 10(6)) is of great significance for control-stability analysis, control laws design, and overall design. By comparing the numerical simulation results of the different airfoils arrangements, the authors have found that model A is more appropriate for folding configuration and model B will generate more obvious unbalanced downwash flow influence. The lift, drag, and hinge moment of the canard and wing vary significantly during the deploying process. This phenomenon is due to the aerodynamic interference and mutual coupling between the canard and wing. Moreover, the rapider deformation rate will cause higher variable quantity of the unsteady aerodynamic characteristics. The additional movement plays a dominant role in the variable quantity compared with the hysteresis effect. The authors have also tested the catapult launching under folded condition and unfolded condition. And the experimental results coincide better with the simulation results.