Methods of Visually Determining the Air Flow Around Airplanes
This is a 1932 NACA technical report issued by the National Advisory Committee for Aeronautics in the United States, written for aeronautical engineers and researchers, describing ways to make airflow around aircraft visible. Its pictures are grainy black-and-white photographs and line diagrams of airplane wings, fuselages and propeller hubs marked with smoke trails and streamer lines, showing how flow patterns can be read directly from the air. A designer could take from them the look of flow lines and smoke streaks traced over solid forms, a useful reference for motion and directional graphics.
