Ford Trimotor - Design and Development

Design and Development

The story of the Ford Trimotor began with William Bushnell Stout, an aeronautical engineer who had previously designed several aircraft using principles similar to those of Professor Hugo Junkers, the noted German aircraft designer.

In the early 1920s Henry Ford, along with a group of 19 other investors including his son Edsel, invested in the Stout Metal Airplane Company. Stout, a bold and imaginative salesman, sent a mimeographed form letter to leading manufacturers, blithely asking for $1,000 and adding: "For your one thousand dollars you will get one definite promise: You will never get your money back." Stout raised $20,000, including $1,000 each from Edsel and Henry Ford.

In 1925, Ford bought Stout and its aircraft designs. The single-engine Stout design was turned into a multi-engine design the Stout 3-AT with three Curtiss-Wright air-cooled radial engines. After a prototype was built and test flown with poor results, and a suspicious fire causing the complete destruction of all previous designs, the "4-AT" and "5-AT" emerged.

That the Ford Trimotor used an all-metal construction was not a revolutionary concept, but certainly more advanced than the standard construction techniques in the 1920s. The aircraft resembled the Fokker F.VII Trimotor, but unlike the Fokker, the Ford was all-metal, allowing Ford to claim it was "the safest airliner around." Its fuselage and wings were constructed of aluminum alloy which was corrugated for added strength, although the drag reduced its overall performance. This has become something of a trademark for the Trimotor. Although designed primarily for passenger use, the Trimotor could be easily adapted for hauling cargo, since its seats in the fuselage could be removed. To increase cargo capacity, one unusual feature was the provision of "drop-down" cargo holds below the lower inner wing sections of the 5-AT version.

One 4-AT with Wright J-4 200 hp engines was built for the U.S. Army Air Corps as the C-3, and seven with Wright R-790-3 (235 hp) as C-3As. The latter were upgraded to Wright R-975-1 (J6-9) radials at 300 hp and redesignated C-9. Five 5-ATs were built as C-4s or C-4As.

The original (commercial production) 4-AT had three air-cooled Wright radial engines. It carried a crew of three: a pilot, a co-pilot, and a stewardess as well as eight or nine passengers . The later 5-AT had more powerful Pratt & Whitney engines. All models had aluminum corrugated sheet metal body and wings. However, unlike many aircraft of this era, extending through World War II, its flight control surfaces (ailerons, elevators, and rudders) were not fabric covered, but rather, they were also made of corrugated metal. As was common for the time, its rudder and elevators were controlled by wires that were strung along the external surface of the aircraft. Similarly, engine gauges were mounted externally, on the engines, to be read by the pilot while looking through the aircraft windshield. Another anachronism was the use of the hand-operated "Johnny Brake."

Like Ford cars and tractors, these Ford aircraft were well-designed, relatively inexpensive, and reliable (for the era). The combination of metal structure and simple systems led to their reputation for ruggedness. Rudimentary service could be accomplished "in the field" with ground crew able to work on engines using scaffolding and platforms. In order to fly into otherwise-inaccessible sites, the Ford Trimotor could be fitted with skis or floats.

The rapid development of aircraft at this time (the vastly superior Douglas DC-2 was first conceived in 1932), along with the death of his personal pilot Harry J. Brooks on a test flight, led to Henry Ford's losing interest in aviation. While Ford did not make a profit on its aircraft business, Henry Ford's reputation lent credibility to the infant aviation and airline industries, and Ford helped introduce many aspects of the modern aviation infrastructure, including paved runways, passenger terminals, hangars, airmail, and radio navigation.

In the late 1920s, the Ford Aircraft Division was reputedly the "largest manufacturer of commercial airplanes in the world." Alongside the Ford Trimotor, a new single-seat commuter aircraft, the Ford Flivver or "Sky Flivver" had been designed and flown in prototype form but never entered series production. The Trimotor was not to be Ford's last venture in aircraft production. During World War II, the largest aircraft manufacturing plant in the world was built at the Willow Run, Michigan plant, where Ford produced thousands of B-24 Liberator bombers under license from Consolidated Aircraft.

William Stout left the Metal Airplane division of the Ford Motor Company in 1930. He continued to operate the Stout Engineering Laboratory, producing various aircraft. In 1954, Stout purchased the rights to the Ford Trimotor in an attempt to produce new examples. A new company formed from this effort brought back two modern examples of the trimotor aircraft, renamed the Stout Bushmaster 2000, but even with improvements that had been incorporated, performance was judged inferior to modern designs.