Mil Mi-6 "Hook"

Mil Mi-6 "Hook"

For more than ten years the Mi-6 has remained, dimensionally at least, the world's largest helicopter, and it was also the first turbine-powered helicopter to go into production in the Soviet Union. The first of five prototypes, flown by Rafail Kaprelian, made its maiden flight in autumn 1957, originally without the shoulder-mounted stub wings which are sometimes fitted to production Mi-6's. Considering the size of the machine, the flight development period of the Mi-6 was relatively short, and production is believed to have started early in 1960. During flight trials the Mi-6 established a number of impressive load-to-altitude and speed-with-payload records in 1959, most of which it bettered three years later when it set a total of eleven new FAI world records. In one of these, still unbeaten by early 1968, it lifted a payload of 20,117kg - greater than the entire weight of the biggest helicopter outside of the Soviet Union, the Sikorsky S-64A.

An initial batch of thirty production Mi-6's was undertaken, but this has undoubtedly now been exceeded, since the Mi-6 is known to be in both military and civil service inside the USSR and examples have also been supplied to the air forces of Algeria, Egypt, Ethiopia, Iraq, Syria, Vietnam and Peru. As a military transport the Mi-6 is capable of carrying up to 70 armed troops and has large rear clamshell loading doors for heavy loads such as army vehicles or large palleted items of freight. The Mi-6's in service with Aeroflot are employed mainly as freighters, in which role they have an internal capacity for 12000kg of payload. The standard passenger version seats 65 people normally, although up to 120 persons can be accommodated in a high density seating arrangement. If used as an ambulance, the Mi-6 can carry 41 stretchers and 2 medical attendants.

Despite the existence of the later Mi-10, the Mi-6 is still utilised in the flying crane role, when the stub wings (which provide some 20 per cent of the total lift) are usually omitted. The Mi-6 has already demonstrated publicly its ability to airlift such large items as the Vostok space capsule and would clearly be of equal use in large engineering projects, such as bridge-laying, the transport of oil drilling rigs, or even the transport of radio towers. The under-fuselage hook can support an externally slung load of 9000kg.

When first announced, following its maiden flight in September 1957, the Mil Mi-6 (NATO reporting name 'Hook') was by far the world's largest helicopter. Its maximum payload exceeds the total weight of the Sikorsky S-64A, which on its appearance a decade later was the largest helicopter outside the USSR. Developed to meet both VVS and Aeroflot requirements, the Mi-6 was also the first turbine-powered helicopter to enter production in the USSR. Five aircraft were involved in the development programme, which was completed very quickly for such a revolutionary aircraft, with production beginning in 1960. O.f conventional helicopter configuration, the Mi-6 introduced two readily-detachable short-span shoulder wings which offload the rotor by some 20 per cent in cruising flight; for heavy-lift operations the stub wings are removed to give greater payload capability. The Mi-6 was used in 1962 to set up no fewer than 14 speed and height-with-payload records that were ratified by the FAI; four of these remained unbeaten in 1983. Major production version was the Mi-6A of which more than 800 had been delivered when manufacture ended in 1981. The 'Hook' was exported to Algeria, Egypt, Ethiopia, Iraq, Syria, Vietnam and Peru, where it. is used by both the air force and army. Flown by a crew of five, the Mi-6 has also seen extensive use with Aeroflot in civil engineering support work on projects such as bridge-laying, and as a versatile heavy transport in areas inaccessible to other vehicles. Another version, developed into the Mil-10 'Harke', is optimized as a flying crane.

General characteristics

• Crew: 6 (pilot, copilot, navigator, flight engineer, radio operator, technician)
• Capacity: ** 90 passengers or
  • 70 airborne troops or
  • 41 stretcher cases with 2 medical personnel
• Payload: 12,000 kg (26,400 lb) of internal cargo
• Length: 33.18 m (108 ft 10 in)
• Rotor diameter: 35.00 m (114 ft 10 in)
• Height: 9.86 m (32 ft 4 in)
• Disc area: 962.1 m² (10,356 ft²)
• Empty weight: 27,240 kg (60,055 lb)
• Loaded weight: 40,500 kg (89,285 lb)
• Max. takeoff weight: 42,500 kg (93,700 lb)
• Powerplant: 2 × Soloviev D-25V turboshaft, 4,100 kW (5,500 shp) each
• Fuel load: 6,315 kg (13,922 lb)

Performance

• Maximum speed: 300 km/h (162 kt)
• Cruise speed: 250 km/h (135 kt)
• Range: 620 km (385 miles)
• Ferry range: 1,450 km(900 miles)
• Service ceiling: 4,500 m (14,750 ft)
• Disc loading: 44.17 kg/m² (9.05 lb/ft²)
• Power/mass: 0.21 kW/kg (0.13 hp/lb)