Wind-tunnel tests of a Clark Y wing having split flaps with gaps
This is a 1938 NACA technical report of wind-tunnel test data on a Clark Y airfoil fitted with split flaps that have gaps, issued by the NASA Technical Reports Server collection for aeronautical engineers and researchers. Its pictures are plain line graphs of lift, drag, pitching moment and centre of pressure against angle of attack, plus a cross-section diagram of the wing profiles with flap geometry, drawn in thin black lines on squared grids; a designer could take their clean grid-and-curve layout as a model for technical charts.
