Mil Mi-4

The Mil Mi-4 (USAF/DoD reporting name "Type 36", NATO reporting name "Hound") is a Soviet transport helicopter that served in both military and civilian roles.

Design and development
The Mi-4 was designed in response to the American H-19 Chickasaw and the deployment of U.S. helicopters during the Korean War. While the Mi-4 strongly resembles the H-19 Chickasaw in general layout, including the innovative engine position in front of the cockpit, it is a larger helicopter, able to lift more weight and built in larger numbers. The first model entered service in 1953. The helicopter was first displayed to the outside world in 1952 at the Soviet Aviation Day in Tushino Airfield.

Operational history
The Mi-4 transport helicopter laid the groundwork of Soviet Army Aviation. It was widely used both in the armed forces and in Soviet civil aviation, and for several decades remained the main type of helicopter in the inventory of the Soviet Armed Forces and of the Civil Air Fleet. The Mi-4 went out of service with the development of the Mi-8. It is no longer used by the Russian Air Force, though it remained in service in some countries as a utility helicopter or as a military transport a while longer. Albania was thought to be the final country using the helicopter, and by 2005 all were out of service. The Mi-4 played a very important role in the Bangladesh liberation war of 1971. The Mi-4 was the workhorse of the Indian Air Force covering the medium lift role at the time. A highly successful heli-borne operation, the Meghna Heli Bridge, using Mi-4s helped the Indian Army's 57 Mountain Division clear the Meghna River. The helilift of a battalion of Indian troops to the outskirts of Sylhet was the first heli-borne operation of the Indian army.

Much like the UH-1 Huey, after it was gradually phased out of military service, it was used in various domestic roles: search and rescue, firefighting, polar expeditioning, construction site cargo helicopter, commercial flights and many others.

An official video of a North Korean Air Force combat flying skills competition released in 2014 shows that the Mi-4 is still in limited service in North Korea.

Variants

 * V-12
 * Prototype. Designation reused for the Mi-12.


 * Mi-4 (NATO – Hound-A)
 * Basic production version.


 * Mi-4A
 * Assault transport helicopter.


 * Mi-4AV
 * Armed versions based on the Mi-4A. V for Vooruzhenniy (Armed). Mi-4A with additional armament. Modification of 1967 had weapons complex K-4V, included four 9М17М ATGM "Phalanga" and 96 57-mm NAR S-5M in six blocks UB-16-57U (or six 100-kg bombs or four 250-kg bombs or tanks with an incendiary substance); 185 helicopters were converted to Mi-4AV.


 * Mi-4GF
 * Factory designation for demilitarised Mi-4 for use in the Civil Air Fleet.


 * Mi-4L Lyukes
 * Six-seat VIP transport version, sometimes converted into an air ambulance helicopter.


 * Mi-4VL
 * Fire-fighting version of Mi-4L.


 * Mi-4M (NATO – Hound-C)
 * Anti-submarine warfare helicopter with searching radar station SPRS-1 ("Kurs-M"), hydroacoustic station "Baku", additional fuel tank and rescue boat with operator in under-fuselage gun turret.


 * Mi-4ME
 * Export modification of Mi-4M.


 * Mi-4VM
 * Slightly modified version of Mi-4M, differed by some avionics system.


 * Mi-4MR
 * Upgraded version of Mi-4VM with the searching radar station "Rubin-V" instead of "Kurs-M".


 * Mi-4P / Mi-4VP
 * Civil transport helicopter, with accommodation for between 8 and 11 passengers, plus eight stretchers and a medical attendant for air ambulance duties. It has square. windows compared to the circular windows of the military versions.


 * Mi-4PL (NATO – Hound-B)
 * Anti-submarine warfare helicopter.


 * Mi-4PS
 * SAR version.


 * Mi-4S Salon
 * VIP transport helicopter.


 * Mi-4Skh
 * Multi-role agricultural helicopter, with a large chemical container in the main cabin. Also used as a fire-fighting helicopter.


 * Mi-4T
 * Major military production version, equipped with a large diameter main rotor and bulged windows.


 * Mi-4VM (VM-12)
 * Anti-submarine warfare helicopter.


 * Mi-4BT
 * Minesweeper with floats.


 * Mi-4RI
 * Mi-4M equipped with the Rion experimental sonar.


 * Mi-4MT
 * Torpedo-carrying ASW attack (killer) aircraft derived from Mi-4M.


 * Mi-4MU
 * Attack helicopter.


 * Mi-4MO
 * Search helicopter with Oka sonar.


 * Mi-4MS
 * Search helicopter with Soora infra-red sensor.


 * Mi-4FV (Mi-4KV)
 * Photographic and guidance helicopter.


 * Mi-4Schch
 * "Polar version" of Mi-4FV for working at the Soviet Arctic and Antarctic research stations.


 * Mi-4SP
 * Special rescue modification.


 * Mi-4PG
 * Experimental version equipped with an external load sling system.


 * Mi-4SV
 * Mi-4 with improved heat insulation for working in the Far North.


 * Mi-4N "Filin" (Horned owl)
 * Experimental reconnaissance version intended for night-time use.


 * Mi-4KK (Mi-4VKP)
 * Mobile command post.


 * Mi-4KU (Mi-4VPU)
 * Mobile command post for controlling Air Force units.


 * Mi-4U
 * Target-designator version carrying the Oospekh (Success) system.


 * Mi-4GR
 * Mi-4 fitted with Grebeshok-3 (Haircomb-3) wide-range panoramic detection and relay radar.


 * Mi-4TARK
 * TV-equipped artillery reconnaissance and spotting helicopter.


 * Mi-4MK (Mi-4PP)
 * ECM version.


 * Mi-4UM
 * Radio-controlled target drone version.


 * Harbin Z-5
 * Chinese military transport helicopter. Chinese production version.


 * Harbin Z-6
 * Prototype turbine powered version of the Z-5, no production undertaken.


 * Xuanfeng
 * Chinese civil transport helicopter. Chinese production version.


 * Unnamed Variants


 * Mi-4 minelayer version produced by converting troop-carrier helicopters.
 * Mi-4 modified for transporting and laying gas pipelines.
 * Mi-4 with Panorama 360 cin  camera system produced by conversion.
 * Mi-4 with the Pristavka (Add-on) radio equipment developed in 1957 for guidance of remote-controlled reconnaissance balloons.
 * Mi-4s used as testbeds. Apart from the above-mentioned versions, the Mi-4 and Mi-4A were widely used as testbeds of various kinds for testing subassemblies and systems of future aircraft, as well as equipment for other branches of industry.

Operators
Since 1957, 22 Mi-4 Hound A have been imported. After severing diplomatic relations with the Soviet Union in 1967, Albania imported 37 Chinese-made Z-5s. In 1961 and 1974, 85 Mi-4 Hound A were imported.
 * Afghan Air Force
 * Afghan Air Force
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 * Algerian Air Force
 * 🇧🇩 Bangladesh
 * Bangladesh Air Force
 * People's Republic of Bulgaria
 * Bulgarian Air Force
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 * Cambodian Air Force
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 * Revolutionary Armed Forces
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 * East German Air Force
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 * Lufthansa
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 * Egyptian Air Force
 * Finnish Air Force
 * Hungarian People's Republic
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 * Indian Air Force
 * Indonesian Air Force
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 * Khmer Republic
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 * Laos
 * Royal Lao Air Force
 * Lao People's Liberation Army Air Force
 * undefined
 * Mali Air Force
 * Laos
 * Royal Lao Air Force
 * Lao People's Liberation Army Air Force
 * undefined
 * Mali Air Force
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 * Mongolian Air Force
 * North Korean Air Force
 * Polish People's Republic
 * Polish Air Force
 * Polish Navy
 * Socialist Republic of Romania
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 * Somali Air Corps
 * Aeroflot
 * Soviet Air Force
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 * Aeroflot
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