Modelling the Impact of a Gust on a Small Unmanned Cruise Vehicle

This study investigates the performance and gust response of a modelled Unmanned Aerial Vehicle (UAV) during cruise flight, highlighting the effects of varying levels of structural flexibility. The UAV model used in this study is not intended to represent a specific real-world aircraft; it is employed solely as an academic example. Using the Bristol Nonlinear Beam Shape aeroelastic framework, which enables the accurate prediction of the aeroelastic responses of flexible structures, three configurations of the UAV were analysed: the original model, as well as 70% and 20% of its original flexibility. The research explores different operational altitudes and Mach numbers to understand how these factors influence the UAV's dynamics. Key results include an assessment of the effects of flexibility on trim conditions, the wing root bending moment envelopes subjected to 1-cos gust inputs with gradients of H = 10, 50, and 100 m, and the corresponding flight dynamics frequencies and damping characteristics for longitudinal and lateral-directional dynamics. The findings demonstrate that flexibility significantly influences the UAV's performance, particularly impacting the pitch angle and elevator deflection during trim conditions. Additionally, increased flexibility correlates with a reduction in wing root bending moments in response to gusts.