Stinson Model U Trimotor of 1932

The Stinson trimotored “Model U” was basically a transport-type high-wing monoplane with seating arranged for 10 passengers and a crew of two. Often called a sesqui-plane (wing and a half) because of the thick lower stub wing that the new “Trimotor” used to mount the recently developed Lycoming transport-type engines of 240 hp each. The design made for a much “cleaner” aerodynamic configuration, despite its increased bulk. The Model U offered gains in operating efficiency and performance over its predecessor Model T. Stinson began delivering the Model U in 1932.

At least 16 of the new “Airliners” were hurriedly put into service on various American Airways routes. Transamerican Airlines operated one initially on alternate routes among Buffalo, Cleveland, Detroit and Chicago; Eastern Air Transport operated a special Wright-powered version (Model U-1) for evaluation on their eastern seaboard system. One example of the trimotored U was specially fitted as an eight-place deluxe“club plane,” with plush accommodations for the executives of the San Francisco Examiner, a Hearst newspaper.

A big beautiful airplane that was studded with an array of mechanical and aerodynamic refinements, the Model U offered more payload at better speeds over that of the “Model T” (SM-6000-B). But these increases were quite small in comparison to the rapidly mounting demands. As a consequence, its actual service life on major routes was quite short, as it was rapidly replaced by still larger and faster equipment. A good indication of the transition taking place in the nation’s airlines is illustrated by the fact that in July 1932 some 580 aircraft were operated by the various lines. One year later in July 1933, the number of aircraft operated had dropped to 544, but the lines were handling considerably more business.

The lower stub wing was arranged to offer bracing for the main wing, to offer mounts for the outboard engines and attachment point for the landing gear. Compartments for the stowage of baggage and cargo were also provided in the thick stub wings. Primarily arranged as a coach-type transport for 10 passengers, the “U” was also available in various other interior combinations. For combination loads of passengers and mail/cargo, either one or two of the front seats in the main cabin could be removed and replaced with auxiliary cargo bins. Initially operated by a crew of two, the copilot was later dispensed with . . .