Clerget are best known for their well engineered rotary engines produced from 1911 to the end of World War I in 1918, the first of their type to deliver fuel-air mixture to the cylinder heads by external induction tubes via externally push rod operated inlet valves. They later made a series of static radial aircraft diesel engines. The experimental 16X was a departure from all of these, first run in 1918. Despite contemporary descriptions as a radial engine, it was in more modern terms an X-type, four stroke water-cooled petrol engine, essentially two 90° V-8 cylinder engines, one inverted, coupled to a common output shaft.
Type: 16-cylinder X-type piston engine, with four 4-cylinder banks separated by 90°. Single sparking plug on the upper side of each cylinder.