The lightness and high thermal conductivity of aluminum pistons are conceded and the paper deals principally with their thermal properties, inclusive of the actual operating temperature of the pistons, the temperature distributions in the piston and the effects of the cooling-water temperature and the piston material on the piston temperature. The apparatus is illustrated and described, and charts are presented and commented upon in connection with a discussion of the results obtained.
Theories affecting piston design are presented and discussed, reference being made to diagrams relating to design procedure: The work is supplementary to that done in 1921 by the authors, which they presented in a similar paper to which they refer.