Analysis of flight and wind-tunnel tests on Udet airplanes with reference to spinning characteristics
This is a 1929 NACA technical memorandum by the National Advisory Committee for Aeronautics, analysing flight and wind-tunnel tests on Udet aircraft to study spinning behaviour, written for aeronautical engineers. Its pictures are dense technical line graphs with plotted curves, axis labels and dashed and solid traces comparing angle of attack against speed ratios, rudder deflection and moments. A designer might take from them the restrained grid-and-curve vocabulary of early engineering documentation, with its sparse palette, fine hairlines and labelled annotation.
