The Mi-4 is a Soviet single-engine medium-lift helicopter. It can carry up to 15 passengers or 1,600 kg of internal cargo in addition to two pilots. The prototype made its first flight in 1952. Although larger, it was heavily influenced by the American Sikorsky S-55.
The Finnish Air Force acquired three Mi-4s in November 1961. They were transported by train to Pori, where they were assembled at the Satakunta Wing under the guidance of Soviet technicians. The helicopters were handed over to the Air Force in February 1962, and in June the wing’s Helicopter Flight with the Mi-4s were transferred to Utti.
In addition to training and general transport, the Mi-4s were used for medical evacuation and maritime search and rescue. The type was well-suited to erecting power line towers and other lifting operations. The Mi-4s also supported teams of the Departments of Geodesy, Topography and Forestry in Lapland during summer. Mi-4 operations gave the Finns a valuable insight into the principles and possibilities of large-helicopter employment.
The Mi-4s proved to be very reliable although maintenance-heavy. The type had good handling characteristics and could be flown very precisely when needed. The helicopters were sent to the Soviet Union for a major overhaul three times during their service life ‒ one example even went east four times. The Air Force’s Mi-4s clocked 8,324 hours, of which the museum’s HR-1 accounted for 2,489 hours. It was withdrawn from use in January 1978.
Mil Moscow Helicopter Plant, Soviet Union
Length of the fuselage 16.79 m; Maximum speed 185 km/h; Main rotor diameter 21 m; Height 4.40 m.
Single-engine medium-lift helicopter