An investigation was made in the 7- by 10-foot wind tunnel of an NACA 23012 airfoil equipped with a Handley Page slat and a slotted and a split flap. The purpose of the investigation was to determine the aerodynamic section characteristics of this airfoil with and without flaps, as affected by the location of the Handley Page slat. A range of slat-nose locations was investigated both with and without flaps at a constant slat gap, and the effect of slat gap was investigated for the slotted flap deflected 40º. The slat position for maximum lift, polars for slotted and split flaps for the most favorable slat arrangements for maximum lift, and complete section data for the most favorable slat arrangements are included. Contours of slat-nose location are given for maximum lift coefficient, for angle of attack for maximum lift coefficient, and for drag and pitching moments at selected lift coefficients.