Igor Vyacheslavovich Chetverikov joined Central Construction Bureau 1931 and soon appointed head of marine brigade at old Menzhinskii factory. Major task new long-range flying-boat for Morskaya Aviatsya. This flew as No. 11 on 14 January 1932, service designation MDR-3, led to Tupolev’s ANT-27 MDR-4. SPL (OSGA-101) was small flying-boat foldable for carriage aboard submarine, complete December 1934 after Chetverikov opened OKB at Sevastopol to build ARK-3 Arctic flying-boat, flown 1936 but abandoned after failures. MDR-6 (Chye-2), high-performance patrol/bomber flying-boat, flown July 1937, was designer's only real success. TA 10-seat amphibian 1947 remained 3 prototypes, OKB closed 1948.