The Curtiss K-12 was a milestone in the development of liquid-cooled aircraft engines and was regarded as one of the most advanced in the world for its time.

It relied upon high rpm and reduction gearing to develop the same power as larger engines.

The K-12 design led to the development of the very successful Curtiss D-12 (1922) engine used in fighters and racing planes.

By 1926 the D-12 design had evolved into the more powerful Curtiss V-1570 "Conqueror," noted for its use in military aircraft.

This article incorporates text from a public domain work of the United States Government.