Viktor Federovich Bolkhovitinov was mercurial professor at VVA (Zhukovskii air force academy) 1932. Following year became head of group, in effect an OKB, with first task to design replacement for TB-3 heavy bomber. Result was DB-A, designation from long-range bomber, academy (5 March 1936). Two prototypes, one of which (N-209) vanished beyond N. Pole 12 August 1937. Second design, S, 2-seat fighter with 2 engines in tandem in nose 1939. Other projects incomplete.