Samuel Dalziel Heron (18 May 1891 – 10 July 1963) was a British born aerospace engineer who made major contributions to the design of piston engines. While working in Britain he carried out the first systematic research into air-cooled cylinders. In the U.S.A he contributed to the design of the Curtiss R1454, invented the sodium cooled poppet valve and became technical director for aeronautical research for the Ethyl Corporation.