The effects of partial-span slotted flaps on the aerodynamic characteristics of a rectangular and a tapered N.A.C.A. 23012 wing
This is a 1939 NACA technical report from the NASA Technical Reports Server, issued as an aeronautical engineering study of wind-tunnel test results for partial-span slotted flaps on rectangular and tapered wings. Its pictures are dense engineering charts of lift, drag and pitching-moment curves plotted on gridded axes, plus one cross-section airfoil diagram with dimensioned flap geometry. A designer might take from them only the restrained, functional visual language of mid-century technical graphics: fine black line work, grid structure, and labelled dimension callouts.
