The Pressure Available for Ground Cooling in Front of the Cowling of Air-cooled Airplane Engines
This is a 1938 NACA technical note on aerodynamics, published by the National Advisory Committee for Aeronautics for aeronautical engineers and researchers studying air-cooled aircraft engines. Its pages carry measured pressure curves plotted against propeller radius and blade-angle settings, dimensioned drawings of test propeller noses and blades, and photographs of a model engine set-up with a propeller. A designer could take from them the clean line-graph layout, the technical drawing conventions, and the propeller silhouettes.
