Seversky SEV-3 / BT-8
Built by EDO for refugee Russian WWI pilot Alexander de Seversky, the SEV-3 set several speed records in 1933. Seversky and fellow Russkies had formed an American corporation in 1931 but since they didn't have a factory of their own at the time, the first airplane was built by EDO and given the SEV-3 classification, with the "3" standing for its three seat configuration. Seversky set amphibian speed records in the plane, powered by a 420 hp Wright Whirlwind, and then went after military business.
The Army tested the Seversky but since it had no need for an amphibian at the time, the builder converted it into a landplane which was given the stamp of approval and the result was the order for the BT-8 basic trainer. This was the Army's first monoplane training aircraft and its first all-metal trainer built using modern construction techniques.
Seversky went on to build other versions of the plane. A single-seat design won the Air Corps pursuit plane competition in 1935 and the basic aircraft evolved into the P-43, later, with a stretch of the fuselage and a 2,000 hp Pratt & Whitney R-2800 engine, it became the P-47 Thunderbolt.