Mil Mi-4 "Hound"

Mil Mi-4 "Hound"

Design of the Mil Mi-4, a conventional helicopter with about four times the capacity of the Mi-1, was initiated in 1951 and the first example was flown during May 1952. Produced initially for use by the Soviet armed forces in assault and troop transport roles, the Mi-4 'Hound-A' has clamshell rear doors to simplify the loading of vehicles and freight; alternatively, the cabin can accommodate up to 14 troops. Military Mi-4s are recognisable easily by having a ventral gondola which was intended originally for a navigator or observer, but can also house avionics equipment. Produced in large numbers for Soviet military use, the Mi-4 was also exported for service with more than 20 foreign air arms. A number remain in current use, and in more recent years conversions have been reported in Soviet use for ASW ('Hound-B') armed close support and ECM ('Hound-C'). From 1964 production of civil versions was initiated and combined civil/military production by Mil was estimated at 3,500 when production terminated in 1969. All versions can be equipped with inflatable pontoons which, mounted so that the landing wheels project below them, can be used for amphibious operations. The Mi-4 was also manufactured under licence in China, a total of about 1,000 built when production ended in 1979, and of which approximately two-thirds were for civil use.

The Mi-4 was produced initially as a troop and assault transport helicopter for the Soviet armed forces. This version is characterised by circular cabin windows and a ventral fairing in which an observer can be stationed if required. Alternatively an additional fuel tank can be fitted in this position. One major difference between the Mi-4 and the S-55 is that the former has clamshell rear loading doors through which a maximum internal payload of 1600kg can be admitted. Typical military loads of the Mi-4 include 14 fully equipped troops, a GAZ-59 command vehicle, a 76mm anti-tank gun or 2 motorcycle combinations. Military Mi-4's have been exported to a number of air forces in the Soviet bloc, among the largest users being India, which has sixty, and Cuba, which has twenty-four.

From 1964 two civil versions of the Mi-4 were also built in considerable numbers. These were the Mi-4P (Passajirskii == passenger) and the Mi-4S (Selskokhoziaistvennii = rural economy). The Mi-4P is the standard version for Aeroflot, carrying 11 passengers normally or up to 16 in high density seating or, in the ambulance role, 8 stretchers and a medical attendant. The Mi-4P is distinguished by having square cabin windows, wheel spats and no ventral fairing; 100kg of baggage can be carried in addition to the normal passenger complement. The Mi-4S is normally used for agricultural operations, when it can be fitted with a 1000kg dust hopper or a 1600-l tank holding pesticide or fire-fighting chemical. All versions of the Mi-4 have provision for fitting inflatable pontoons in addition to the wheeled landing gear. A stripped-down Mi-4 established a number of speed-with-payload and payload-to-altitude records in 1956, and in more recent years both military and civil Mi-4's have performed a considerable amount of useful work in the Polar regions, their tasks including ice patrol and geological survey.

General characteristics

• Crew: One or two pilots
• Capacity: 16 troops or up to 1,600 kg (3,520 lb) of cargo
• Length: 16.80 m (55 ft 1.4 in)
• Rotor diameter: 21.00 m (68 ft 11 in)
• Height: 4.40 m (14 ft 5 in)
• Disc area: 346.4 m² (3,727 ft²)
• Empty weight: 5,100 kg (11,220 lb)
• Loaded weight: 7,150 kg (15,730 lb)
• Max. takeoff weight: 7,550 kg (16,610 lb)
• Powerplant: 1 × Shvetsov ASh-82V radial engine, 1,250 kW (1,675 hp)

Performance

• Maximum speed: 185 km/h (116 mph)
• Range: 500 km (313 mi)
• Service ceiling: 5,500 m (18,040 ft)
• Rate of climb: m/s (ft/min)
• Disc loading: 41 kg/m² (8 lb/ft²)
• Power/mass: 0.21 kW/kg (0.13 hp/lb)