This engine was designed and built by Hugh M. Rockwell in Plainville, CT. In 1917, this developmental engine demonstrated the extensive application of anti-friction bearings to aircraft engine technology. It is an opposed twin, 40 hp, air-cooled engine with two valves per cylinder and weighed 135 lbs. giving it a very favorable power-to-weigh ratio. In the 1920's the cylinder headers were changed along with some other modifications.
The engine on display is a single overhead valve which included Rockwell's patented rudimentary fuel injection system.
In 1960, Albert Rockwell (descendant of the founder of New Departure Manufacturing Company in Bristol, CT, and nephew of Hugh M. Rockwell) donated the engine to the Connecticut Aeronautical Historical Association.
This engine is located in the Military Hangar near the Sikorsky S-16.