Louis Coatalen concentrated on water-cooled engines for the most part, but did design an air-cooled V-12 named Spartan. Little is known of this engine which had a bore of 105 mm (4 in) and stroke of 130 mm (5 in), capacity of 14.03 l (856 cu in) and output of 149 kW (200 hp) driving a propeller through a reduction gearbox. The single overhead camshaft operated two inlet and two exhaust valves per cylinder via rockers and ignition was supplied by two 6-cyl. Magnetos supplying spark to one spark-plug per cylinder.
Produced in 1916/17 as prototypes only, testing was conducted in a Saunders T.1.