Cooling of Air-cooled Engines by Forced Circulation of Air
A 1926 NASA technical report on cooling air-cooled aircraft engines by forcing air through them, issued as a government aeronautics document for engineers and researchers. The first picture is a photograph of a disassembled engine with its propeller group open for inspection, while the second is a lettered line drawing of a streamlined nose cowl with a propeller and airflow arrows, offering a designer clear mechanical schematics of how air moves around a machine.
