Curtiss K-12, V-12 Engine, ca. 1918. Creator: Curtiss Aeroplane and Motor Company.

In 1916 Curtiss engineer Charles Kirkham began designing an engine to compete with the Wright Corporation's Hispano-Suiza. By late 1917, the prototype K-12 (K for Kirkham) was bench tested. While it met its design objectives of high power, low frontal area, compact size, and low weight, the engine encountered technical difficulties during development. Kirkham left Curtiss in 1919, and Arthur Nutt took over the project, eventually producing the D-12, which became a highly successful racing and military power plant in the 1920s. This engine is manufacturer's number 5 out of about 20 built. The K-12 powered the Curtiss Navy 18T Wasp triplane and the Army Curtiss 18B Hornet biplane. In 1919 Curtiss test pilot Roland Rholfs set a new world's altitude record of 10,641 m (34,910 ft) with the 18T.