The Effect of Fillets Between Wings and Fuselage on the Drag and Propulsive Efficiency of an Airplane
This is a 1928 NACA technical report, issued by the United States National Advisory Committee for Aeronautics, on how fillets joining wings to fuselage change drag and propulsive efficiency of an airplane. Its pictures are plain photographs of a cabin monoplane mounted for wind-tunnel testing, and a line chart of thrust, power and efficiency curves plotted against advance ratio. A designer might take from them the clean, technical look of early aviation research: grid-backed graphs and stark black-and-white model photographs.

