The Effect of Surface Irregularities on Wing Drag. I. Rivets and Spot Welds. 1; Rivets and Spot Welds
This is a NACA technical report from 1938 by the National Advisory Committee for Aeronautics, studying how rivets and spot welds on aircraft wing surfaces add drag. Its charts plot increase in drag coefficient against airspeed, Mach number, head height and rivet pitch for flush, brazier-head and countersunk fasteners. A designer can take from them the clean line graphs, dashed and dotted series keyed by symbols, and the small profile sketches of rivet heads above each chart.
