Aerodynamic data for a wing section of the Republic XF-12 airplane equipped with a double slotted flap

Abstract : An investigation was carried out in the Langley two-dimensional low-turbulence tunnels for the purpose of developing an optimum flap configuration for maximum lift on an airfoil section for the Republic XF-12 airplane equipped with a double slotted flap. Lift and flap loads were obtained at several flap deflections for two flap paths. Drag characteristics of the section with flaps retracted were also determined. A maximum lift coefficient of 3.43 was measured for this airfoil-flap combination for a flap deflection of 60 deg at a Reynolds number of 14 million. An investigation of flap and fore flap configurations showed that the configuration for which this maximum lift coefficient was measured was very nearly the optimum. Maximum lift coefficients were shown to increase with Reynolds number for all deflections except the best maximum lift deflection, at which a decrease in Reynolds number from 14 million to 3.5 million caused an increase of about 0.1 in maximum lift coefficient.