Wind-tunnel investigation of an N.A.C.A. 23012 airfoil with two arrangements of a wide-chord slotted flap
This is a 1939 NACA technical report from the NASA Technical Reports Server, a wind-tunnel test study of an airfoil with a wide-chord slotted flap, written for aeronautical engineers. The pictures are engineering line graphs of drag coefficient, lift coefficient, and pitching moment against angle of attack and flap deflection, with a small airfoil cross-section sketch; a designer might take from them the plain grid-and-curve chart style and the clean stepped plotting of data.
