The effects of full-span and partial-span split flaps on the aerodynamic characteristics of a tapered wing
This is a 1934 NASA technical report on wind-tunnel tests of split flaps on a tapered aircraft wing, issued by NACA for aeronautical engineers and researchers. The pictures are engineering graphs of lift, drag and centre-of-pressure curves plotted against angle of attack and flap deflection, drawn in plain black lines on grid paper, with no decorative content a designer could borrow beyond the rigorous plotted form and grid structure.
