1919 King-Bugatti,U-16
In 1915 Ettore Bugatti designed a U-16 engine. In 1917 the USA sent a delegation, the Bolling Commission, to Europe to identify military aircraft and engines that could be produced in the USA. The U-16 was chosen as a design to be produced in the USA. Duesenberg was selected to manufacture the engine
This U-16 engine consist of two banks of eight cylinders each. Each of the banks are made up of two four cylinder blocks. Each crank shaft consist of two parts, joined in the middle with a keyed taper. Both crankshafts are geared to the propeller shaft with a reduction of 0.667:1. At 2000 rpm this engine produces 410 hp
This engine caused the first U.S. casualty in WW I when a service man walked into the propeller while it was running on a test stand in Paris.
The prototype built by Bugatti was sent to the U.S. after only 37 hours of testing. Charles Brady King made a number of improvements. Only about 40 engines were completed by Duesenberg before the end of the war. Some sources clams it was never user in a U.S. aircraft.
National Air and Space Museum, Jan 2014
A good book on Duesenberg aircraft engines from Old Machine Press is Duesenberg Aircraft Engines: A Technical Description by William Pearce.