The few MBR-6’s built were the only real success of designer Igor V. Chyetverikov. A little more than 50 of these highly advanced long range flying boats were produced in the late 1930’s-early 1940’s. The MDR-6’s of the main variant were powered by a pair of radial engines (Shvetsov M-25, M-62 and M-63) and served with the Baltic, Black Sea and Far East fleets until late 1942. Structural defects and faulty fuel system caused their hasty retirement. War then was going badly for the USSR and there was no time to spare in these small production assets…..and there were Lend-Lease Catalinas to burn.
Very beautiful aircraft in their more pedestrian form, the MDR-6 became just gorgeous in its later prototype iterations. In this photo, the first -and prettiest- of those prototypes. The B1 was a total redesign. Slicker and smaller, its designer cleaned it out thoroughly -retracting floats included- and replaced the radial engines with a pair of Klimov M-105 liquid-cooled engines. Add to those features a gorgeous twin-finned tail and the result was just irresistible. It was test flown, crash included, during late 1940-1941.