Aerodynamic and stability analysis of a HVTOL transition unmanned aerial vehicle.

The ability of the Hybrid VTOL UAV to operate for both hovering and level flight makes it highly appealing. A transitional flight is one in which both the rotors and the forward propeller are active and the interaction between the rotors and the main wing takes place. This phenomenon, which influences the lift produced by the primary wing, is not entirely understood. This paper studies the interaction between the propellers and the main wing during straight and level flight conditions and how it affects lift generation. The vertical motors were modelled as actuator disks (AD) to represent the spinning rotors. The wing is designed by careful physical characteristics comparison, selection, and performing CFD analysis of aerofoil DEA-31, at low Reynolds number, i.e., Re = 2 × 105 with varying angle of attack, i.e., α = – 4° to 20° with an interval of 2° to obtain maximum lift generated by the wing. The CFD analysis is performed in ANSYS Fluent and the stability analysis in XFLR5. It has been found that the FWD rotor impacts the oncoming air, causing rotor wash on the wing, which reduces momentum on the bottom of the wing, reducing the lift produced by the wing. The AFT rotor, on the other hand, increases the momentum of the airflow over the upper surface of the wing, decreasing the pressure and enhancing the wing's overall lift. Thus, it is suggested that the AFT rotor be located towards the trailing edge and that the throttle be adjusted somewhat higher to enhance the lift generated by the wing. [ABSTRACT FROM AUTHOR]