The D-12 was a 12-cylinder, water-cooled, V-type engine that was introduced in 1921. It became a successful and popular engine of the 1920's in military aircraft and Curtiss racing airplanes because of its relatively low frontal area. Arthur Nutt designed the D-12 as an improvement to the earlier Curtiss K-12. The engine has cast cylinder blocks for each bank of 6 cylinders and 4 valves per cylinder. The power output was about 400 hp at 2,000 rpm.
When it powered the Fairey Fox in 1925, the fastest airplane in England, it inspired Rolls-Royce to develop its famous Merlin engine. It was used in mail planes until the Pratt & Whitney 9-cylinder, air-cooled Wasp engine came along.
This example was manufactured in 1921. The D-12 was a great step forward in liquid-cooled engines and influenced inline military and racing engines through the start of World War II.
This engine is located in the connector between the Military and Civilian hangars.