In the spring of 1912 Thomas Wesley Benoist announced the completion of his firm's newest aircraft, the Type XII. It was a two-place tractor biplane, powered by a Roberts six-cylinder, 75-horsepower engine. It was one of the first closed-fuselage tractor airplanes to appear in the United States. Perhaps five Type XII aircraft were produced by the Benoist factory during the next year.The NASM Benoist Type XII was constructed in the Benoist shop in St. Louis by its purchasers, Edward and Milton Korn. The Korn brothers began work on their airplane in March 1912. It was completed on May 20, and it was flown soon thereafter at Anna, Illinois. During the following year, the Korns performed numerous exhibitions with their Benoist. Most American aircraft produced during this period were close copies of Wright, Curtiss, or European machines. Benoist was one of the very few U.S. firms building and selling original designs in the pioneer era.