THE National Advisory Committee for Aeronautics has undertaken a research to determine the effect of the fundamental factors influencing the cooling of air-cooled radial engines. This paper presents some of the results of an investigation made to obtain information that can be used in the design of fins for the cooling of heated cylindrical surfaces in an airstream.
An equation has been developed for calculating the quantity of heat dissipated by a given fin-design, using experimentally determined heat-transfer coefficients. The agreement between the quantity of heat dissipated, as determined by experiment and calculated by the equation, was found to be sufficiently close to justify its use.
A method has been developed for determining the fin dimensions, utilizing a minimum of material for a variety of conditions of heat transfer, airflow, and metals. The design of cylinder baffles has also been investigated and results are presented that show the improvement in cylinder-temperature distribution and the increase in the average heat-transfer coefficient to be obtained by the use of shell and integral cylinder-baffles.