CFD-BASED COMPARATIVE AERODYNAMIC ANALYSIS AND AIRFOIL SELECTION FOR ENHANCED CRUISE PERFORMANCE OF HYBRID VTOL UAVs

Hybrid Vertical Take-Off and Landing (VTOL) unmanned aerial vehicles (UAVs) combine the hovering capability of multirotor platforms with the efficient forward-flight performance of fixed-wing aircraft. However, achieving high aerodynamic efficiency during cruise flight remains a significant challenge because the wing operates at relatively low Reynolds numbers, where boundary-layer separation and increased drag can substantially reduce endurance and flight range. This study presents a computational fluid dynamics (CFD)-based comparative aerodynamic analysis of three representative NACA airfoils, namely NACA 0012, NACA 4412, and NACA 23012, to identify a suitable wing section for hybrid VTOL UAV applications. Two-dimensional steady-state simulations were conducted under incompressible flow conditions using the Reynolds-Averaged Navier–Stokes (RANS) equations coupled with the SST k–ω turbulence model. Aerodynamic characteristics, including pressure distribution, velocity field, lift coefficient, drag coefficient, and lift-to-drag ratio, were evaluated under identical operating conditions representative of cruise flight. The numerical results demonstrate that the NACA 4412 airfoil provides the most favorable aerodynamic performance, achieving a lift coefficient of 0.429, a drag coefficient of 0.0817, and the highest lift-to-drag ratio of 5.26 among the investigated configurations. In contrast, NACA 0012 exhibits the lowest drag but produces negligible lift, while NACA 23012 offers moderate aerodynamic performance. These findings indicate that NACA 4412 is the most suitable candidate for improving the cruise efficiency of hybrid VTOL UAVs and provides a practical reference for preliminary wing design and airfoil selection.