Study on Small UAVs' Deep Stall Landing Procedure

In the actual combat application, obstructions or adverse terrain make the landing of UAV the most difficult and most complex stage. In order to achieve the accurate undamaged retrieval of small UAV, the deep stall landing approach is proposed. This paper takes a certain UAV for example where only its longitudinal movement is concerned. Adopting the combination of spring-based smoothing and local cell remeshing method, commercial software FLUENT is used to simulate numerically by calculating unsteady flow equation coupled with six degrees of freedom motion. Then the kinetic process of UAVS deep stall landing as well as the trajectory, force condition and other impressive motion information are obtained. The enlargement of elevator input and decrease of static stability margin do facilitate the development of deep stall state while posing adverse effect during the falling phase. Numerical results show that the deep stall recovery is feasible. Moreover, the CFD-6DOF coupling calculation and the simulation of aircraft deep stall landing process are validated using unstructured dynamic mesh technology.