In the U.S.A he contributed to the design of the Curtiss R-1454, invented the sodium cooled poppet valve and became technical director for aeronautical research for the Ethyl Corporation.

From 1915 to 1916 he worked with Professor A.H. Gibson on the first systematic research into the design of air-cooled engine cylinders.

They concluded that (1) aluminium should be used for efficient conduction (2) the cylinder head should be in one piece because conduction through metal-to-metal interfaces could not be guaranteed (3) the cylinder head should provide the shortest escape path for heat at the hottest parts across the greatest cross section.

He disagreed with J.D Siddeley over the redesign of the Siddeley-Deasy Puma cylinder head and other design policies.

[6] Heron arrived in the United States in 1921 to work on military applications of the two-valve air-cooled cylinder.