<div class="section abstract"><div class="htmlview paragraph">THE Free-Piston Engine Program described in this paper was concerned with determining thermodynamic relationships of small, high-speed engines. The purpose was to establish proper engine geometry and mechanical design which could then be applied to developing larger automotive engines.</div><div class="htmlview paragraph">The author outlines the problems encountered during the Program's beginnings: starting system, powerplant assembly, cooling system, and lubrication.</div><div class="htmlview paragraph">The results indicated that the free-piston engine would be particularly applicable to the farm tractor. The author thinks that such a powerplant may equal or better the diesel engine in economy.</div></div>