Study of Mild-Stall Wings with a Fixed Slat

Much attention has been paid to PAY (Personal Air Vehicle) as a new-generation small aircraft, It is expected that PAY will be widely used as a short-range transport aircraft in the future for countermeasure against traffic jam, One of the key technologies to make PAY much popular is to enhance the safety, which is crucial to small planes, In order to enhance the safety of PAY, mild-stall high-lift characteristics of the wing are especially needed. This study aims to propose a mild-stall wing with a fixed slat for PAY use, Two mild-stall airfoils are combined to form a new rectangular wing: NACA4415 and SLAT4415, NACA4415 is known as a conventional mild-stall airfoil, and SLAT4415 is a fixed slat airfoil based on NACA4415 for further improvement in stall characteristic, The higher lift characteristic ofSLAT4415 was obtained via the optimization by Genetic Algorithm. Designed wings composed ofNAC4415 and SLAT4415 airfoils are numerically analyzed by solving the Navier-Stokes equations on the unstructured mesh to examine the performance at high-angle of attack for low-speed region, The computational results indicate that designed wings are able to achieve mild-stall characteristics, Lift coefficients of the designed wings tend to drop at 22 degrees of A.o.A, however, increase again as A.o.A becomes higher, For further analysis, numerical simulations for the wing that has a taper or that has only SLAT4415 airfoil were also conducted, As a result, it was proved that the designed rectangular wing that has SLAT4415 airfoil of fixed slat only in outboard wing had very mild stall characteristic.