For the Allied effort in World War I, the talents of three future automotive legends came together to produce  an aircraft engine that, unfortunately, never saw duty in combat. Still, it’s a fascinating story.

Not that they require any introduction, but the three mechanical wizards responsible for this remarkable engine were:

+   Ettore Bugatti, the Italian-Alsatian designer whose creations, including the sinewy T35 Grand Prix racer and the collossal Royale, were equal parts art and science.

+   Charles Brady King, who built and drove the first automobile on the streets of Detroit in 1896 and lent his engineering expertise to numerous pioneer car makers, from Maxwell to Oldsmobile.

+   The Duesenberg brothers, Fred and August, who went on to win the Indianapolis 500 three times and create the mighty Duesenberg J, the greatest American car of the Classic era.

The U16 saga begins with Bugatti, who in 1915 completed the design of a large and impressive aircraft engine that caught the attention of the U.S. government’s Bolling Commission, led by Col. R.C. Bolling and American auto industry executive Howard Marmon. They obtained a license from Bugatti to have the engine manufactured in the USA.

The design was then immediately turned over to King for further development, and he directed a series of revisions, mainly in the three-valve, overhead-cam cylinder head and cooling system. This couldn’t have given Bugatti much pleasure, but at least he had the U.S. government’s $100,000 licensing fee to comfort him. The contract to manufacture the engine, in turn, was awarded to the Duesenberg Motors Corporation, which was backed by a group of investors led by J.R. Harbeck, and a large new state-of-the-art factory was built in New Jersey to handle the production. (Duesenberg’s own V16 aircraft engine, featured here, was also built in the New Jersey plant.)

Among the engine’s noteworthy features was its modular construction: It could be assembled as an inline four or a straight eight, with one Miller carburetor and one Dixie magneto for each four-cylinder unit. Or two straight eights could be joined to form a U16, with the two crankshafts coupled via a gear drive. In its giant U16 form, the engine displaced 1483 cubic inches, weighed nearly 1,300 lbs, and was rated at 410 hp. With its twin crankshafts, the U16 was wider and heavier than other engines in its class, notably the Liberty L12, and the engine never flew in combat during the war. However, there are multiple examples of the U16 on display in the USA, including at the Auburn Cord Duesenberg Museum in Auburn, Indiana, below.

WIth the hostilities ended, the big new plant in New Jersey was acquired by Willys and then Durant, while the rights to the U16 engine were acquired by Bréguet, a French aircraft maker. Bréguet’s ambitious development plans for the engine included the Breguet-Bugatti 32A Quadrimotor, below, which combined two U16s on a common output shaft, and it eventually flew in the Bréguet Type XX Leviathan aircraft.