In September 1927 Mid-Continent Aircraft Co. at Tulsa, OK, taken over by group of investors, and Spartan Aircraft Co. formed 17 January 1928, building Spartan 3C-1 and various derived versions by late 1930. Production switched to C4-225 and derivatives, all 4-seat cabin monoplanes, followed by 5-seat C5 and C2-60 braced low-wing side-by-side sport/trainer (165-hp Wright 3-cyl). In 1936 7-X prototype led to 7W Executive low-wing retractable-gear 4-seater, 34 built by 1940 followed by 201 NP-1 trainers for Navy based on C3.