The Ford Trimotor

Silent. 

The Ford Trimotor was a development of previous designs by William Bushnell Stout,  using structural principles copied from the work of Professor Hugo Junkers, the noted German all-metal aircraft design pioneer, and adapted to an airframe very similar to the single engine Fokker F.Vii - even using the same airfoil cross section at the wing root. 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