The Mil Mi-4 assault transport was the product of an October 1951 ultimatum given by Josef Stalin to design and construct a transport helicopter within 12 months. It is a piston-engined aircraft developed for unarmed military transportation. Approximately 3,000 Mi-4 Hounds were built for military service within the Soviet Union and Warsaw Pact countries and for civil operations with the Soviet national airline Aeroflot before production ended in 1969. It was also under production license in the People’s helicopters for transport and antisubmarine operations. The large four-blade main rotor is mounted on top of the fuselage midsection and the single-piston engine in mounted in the nose. The fuselage is short and oval with a solid round nose and stepped-up cockpit. It features a high-mounted, long, thin tail boom with a gun mount under the belly and four-wheeled landing gear. The tail is small, with a three-blade rotor attached to right side of the thin fin and small flats forward of the fin.