Experiments with a Counter-propeller
A 1933 NACA technical report, issued by the National Advisory Committee for Aeronautics and later archived by NASA's Technical Reports Server, written for aeronautical engineers and researchers testing propeller designs. Its two plates are technical diagrams and graphs rather than decorative illustrations. The first plate shows angular geometry of airflow around a wing-like profile with labelled angles and lines, and the second plots curves of angle of attack against a measured quantity, with dashed and solid lines across a gridded chart. A designer might borrow the clean, precise line-and-label vocabulary of early engineering drawings for technical or retro infographic layouts.
