This paper describes an experimental investigation into the surface heat transfer coefficient of finned metal cylinders in a free air stream. Eight cast aluminium alloy cylinders were tested with three different fin pitches and three different fin lengths. The cylinders and their fins were designed to be representative of those found on a small engine. Each electrically heated cylinder was mounted in a wind tunnel and subjected to a range of air speeds between 12 and 50 m/s. The surface heat transfer coefficient, h, was found primarily to be a function of the air speed and the fin separation, with fin length having little effect.