A Study on Aerodynamic Behavior of Subsonic UAVs' Wing Sections with Flaps

In this study, it is aimed to assess the aerodynamic and flight effects of the flap design on an airfoil. For this purpose, NACA 4415 type wing profile, which can also be used in unmanned aerial vehicles (UAVs), is selected. The original design and the +5-degree flapped design which has constant other design features are compared. Assessments are performed under constant Reynolds numbers and an angle of attack between 0-10 degrees with a 1-degree interval. Analyses are made using the open-source software XFLR5. For the flapped design is named NACA 4415-2, some basic aerodynamic performance parameters such as coefficient of drag (CD), coefficient of lift (CL) coefficient of pressure (Cp) maximum lift coefficient (Clmax) and minimum stall velocity (Vstall) have been observed. According to results, when the flap with 5o is added to the airfoil, it has been observed that the CL and Lift force of the original design of the airfoil increase significantly, CD of the airfoil increase partially, and the pressure coefficient tends to decrease significantly. Furthermore, it has been observed that while the minimum stall velocity has decreased, Clmax values increased.