Klimov M-103
The Klimov M-103 is a V12 liquid-cooled piston aircraft engine used by Soviet aircraft during World War II. Offering around 1,000 hp for takeoff, it was used in a fairly small number of designs, with its greatest success being the Tupolev SB. It was soon replaced by the more powerful 1,100 hp Klimov M-105, which arrived in late 1939. Production continued until 1942, by which time almost twelve thousand had been delivered.