Aerodynamic analysis of a VTOL fixed-wing UAV aircraft with conventional control surfaces

Abstract

Vertical Take-Off and Landing (VTOL) Unmanned Aerial Vehicles (UAVs) offer significant advantages in operations requiring both vertical lift and efficient forward flight. However, VTOL aircraft design is challenge in terms of stability, control, and aerodynamic efficiency across flight regimes. Aerodynamic analysis is conducted to determine the variations of pressure distributions, lift and drag forces and center-of-pressure (CP) movement all of which are important towards design optimization and control modeling. This study focuses on aerodynamic analysis of a small VTOL fixed-wing UAV without using any additional actuators or complex tilting mechanisms. The designed UAV only uses the regular control surfaces such as Aileron, Rudder and Elevator of the fixed wing aircraft for maneuverability. Computational fluid dynamics (CFD) has become a essential tool in aerodynamic design and analysis. Studies of flyingwing VTOL UAVs revealed that CFD is effective in the prediction of stability and flow separation which is critical in transition controllability [1]. The structural and CFD studies were also coupled which showed that aeroelastic effects at high lift and inertia can be critical to performance and safety [2]. CFD has also been useful in wing and fuselage optimization to minimize drag and preserve lift as well as in the prediction of aerodynamic coefficients by use of turbulence models to provide reliable control inputs [3]. In addition to CFD, low-order methods like XFLR5 have been used to facilitate initial design through evaluation of centerof-gravity balance and optimization of wing geometry under structural constraints [4] [5]. On this basis, th present work implements CFD and XFLR5 to examine the aerodynamic forces, pressure field, and CP-CG interaction in a fixed-wing UAV-VTOL.