Mikulin AM-37
The Mikulin AM-37 was a Soviet aircraft piston engine designed prior to Russia's entry into World War II. An improved version of the Mikulin AM-35 V12 engine, it was only produced in small numbers because of its unreliability. == Development == Design work on a development of the AM-35 with boosted supercharging and an intercooler positioned behind the supercharger began on the factory's initiative in December 1939.