Measurement of Profile Drag on an Airplane in Flight by the Momentum Method. Part I
This is a 1930 NACA Technical Memorandum, issued by the National Advisory Committee for Aeronautics, reporting flight measurements of profile drag on an airplane using the momentum method. Its pages are dense engineering plots of drag coefficients against speed and pressure for test surfaces such as corrugated sheet metal, plywood covering and duralumin sheet, written for aircraft engineers and researchers. The pictures are grids of intersecting curves, dotted data points and labelled axes, offering a designer little beyond a sparse, technical line-graph vocabulary of thin lines on squared paper.
