NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC
Full-scale nose-slot cowlings were tested in a wind tunnel to furnish information on the pressure drop available for cooling. Of the two basic nose shapes tested, the one with the smaller radius of curvature gave the higher pressure drop across the engine. The maximum pressure drop for high-speed conditions with an engine conductance equivalent to a double-row radial engine is 1.45 and for take-off conditions it is 3.75. When using a propeller with a round blade shank, the values are 1.23 and 1.65 respectively.