Mil Mi-4
The Mil Mi-4 (NATO reporting name 'Hound') is a Soviet transport helicopter built by the Mil Moscow Helicopter Plant. Designed in response to the American H-19 Chickasaw and the Korean War, it first flew in 1952 and entered service in 1953, and for several decades it remained the main helicopter type in the Soviet armed forces and the Civil Air Fleet. More than 4,000 were built, including the Harbin Z-5 production version built in China, and variants filled transport, anti-submarine, search-and-rescue and air-ambulance roles for operators in dozens of countries. The Mi-8 replaced it in Soviet service; survivors are preserved in museums, and a North Korean video released in 2014 showed the type still in limited service there.
Why It Mattered
For several decades the Mi-4 remained the main type of helicopter in the inventory of the Soviet Armed Forces and of the Civil Air Fleet. It had been designed in response to the American H-19 Chickasaw and to the deployment of U.S. helicopters during the Korean War. It was also the larger machine of the two, able to lift more weight than the American design that prompted it. More than 4,000 were built, including the Z-5s built in China, and NATO gave the type the reporting name 'Hound'. In India, where it covered the medium-lift role of the time, it became the workhorse of the Indian Air Force.
Design Notes
Its general layout followed the H-19 Chickasaw's, most notably in the engine position in front of the cockpit, a resemblance the sources remark on rather than any claim of copying. Behind the cockpit, the cabin could carry up to 16 passengers, with a maximum internal payload of 1,600 kg. A single Shvetsov ASh-82V radial engine drove a four-bladed main rotor 21 metres in diameter. The basic transport was adapted into specialised versions: anti-submarine helicopters carrying a searching radar station, a dedicated search-and-rescue version, and a civil version fitted for air ambulance duties. An armed version, the Mi-4AV, followed in 1967, and 185 helicopters were converted to it. China built its own production version, the Harbin Z-5.
Operational History
The Mi-4 first flew in 1952 and entered service in 1953. It was first displayed to the outside world in 1952, at the Soviet Aviation Day at Tushino Airfield. Production began that same year, and the type was used by both the armed forces and Soviet civil aviation. For several decades it remained the main type of helicopter in the Soviet inventory. Exports took it to dozens of air forces: Poland's was a primary user, India made it the workhorse of its air force, and Cuba imported 85 in 1961 and 1974. In the Bangladesh Liberation War of 1971, Indian Mi-4s flew the operation known as the Meghna Heli Bridge, lifting a battalion of Indian troops to the outskirts of Sylhet in the Indian Army's first heli-borne operation. Later, as military use faded, Mi-4s took on domestic roles that included search and rescue, firefighting, polar expeditioning and construction-site cargo flying.
Afterlife
In Soviet service the Mi-4 went out of service with the development of the Mi-8, and it is no longer used by the Russian Air Force. Elsewhere it remained in service in some countries for a while longer, as a utility helicopter or a military transport. Albania was thought to be the final country using the helicopter, and by 2005 all were out of service. A North Korean air force combat flying skills competition video released in 2014 showed the Mi-4 still in limited service in North Korea. Vertipedia, the Vertical Flight Society's database, now lists the type's status as no longer flying. Survivors are preserved in museums, among them a Mi-4AV at the Prague Aviation Museum and examples at Belgrade and Riga.