PART_2 Operational history Construction of the first prototype was completed in 1968. A first flight on 27 June 1967 ended prematurely due to oscillations caused by control problems; one set of main wheels contacted the ground hard bursting a tyre and bending a wheel hub. The cause of the oscillations proved to be a harmonic amplification of vibrations in the cockpit floor feeding back into the control column when a roll demand was input into the cyclic stick. It was widely but erroneously reported in the Western press that the aircraft had been destroyed. The first prototype, given the registration SSSR-21142, made its first flight on 10 July 1968 from the Mil factory pad in Panki to the Mil OKB test flight facility in Lyubertsy. In February 1969, the first prototype lifted a record 31,030 kg (68,410 lb) payload to 2,951 m (9,682 ft). On 6 August 1969, the V-12 lifted 44,205 kg (97,455 lb) to a height of 2,255 m (7,398 ft), also a world record. The second prototype was also assembled at the Mil experimental production facility in Panki but sat in the workshop for a full year awaiting engines, flying for the first time in March 1973 from Panki to the flight test facilities in Lyubertsy. Curiously the second prototype was also registered SSSR-21142. The prototype V-12s outperformed their design specifications, setting numerous world records which still stand today, and brought its designers numerous awards such as the prestigious Sikorsky Prize awarded by the American Helicopter Society for outstanding achievements in helicopter technology. The V-12 design was patented in the USA, Great Britain and other countries. Despite all of these achievements the Soviet Air Force refused to accept the helicopter for state acceptance trials for many reasons, the main one being that the V-12s most important intended mission no longer existed, i.e. the rapid deployment of strategic ballistic missiles. This also led to a reduction in Antonov An-22 production. In May–June 1971 the first prototype V-12 SSSR-21142 made a series of flights over Europe culminating in an appearance at the 29th Paris Air Show at Le Bourget wearing exhibit code H-833. All development on the V-12 was stopped in 1974. The first prototype remained at the Mikhail Leontyevich Mil Moscow helicopter plant in Panki-Tomilino, Lyuberetsky District near Moscow and is still there today (17 August 2013) at 55°40′2″N 37°55′56″E The second prototype was donated to Monino Air Force Museum 50 km (31 mi) east of Moscow for public display. Specifications (V-12) Data from Mils heavylift helicopters : Mi-6, Mi-10, V-12 and Mi-26, Janes All The Worlds Aircraft 1975-76 General characteristics Crew: 6 (pilot, copilot, flight engineer, electrician, navigator, radio operator) Capacity: 196 passengers normal 20,000 kg (44,000 lb) maximum 40,000 kg (88,000 lb) Length: 37 m (121 ft 5 in) Wingspan: 67 m (219 ft 10 in) across rotors Height: 12.5 m (41 ft 0 in) Empty weight: 69,100 kg (152,339 lb) Gross weight: 97,000 kg (213,848 lb) Max takeoff weight: 105,000 kg (231,485 lb) Freight compartment: 28.15×4.4×4.4 m (92.4×14.4×14.4 ft) Powerplant: 4 × Soloviev D-25VF turboshaft engines, 4,800 kW (6,500 shp) each Main rotor diameter: 2× 35 m (114 ft 10 in) Main rotor area: 962 m2 (10,350 sq ft) 5-bladed rotors located transversely Performance Maximum speed: 260 km/h (162 mph; 140 kn) Cruising speed: 240 km/h (149 mph; 130 kn) Range: 500 km (311 mi; 270 nmi) Ferry range: 1,000 km (621 mi; 540 nmi) with external fuel tanks Service ceiling: 3,500 m (11,483 ft) Disk loading: 101 kg/m2 (21 lb/sq ft) at gross weight Hovering ceiling in ground effect: 600 m (2,000 ft) Hovering ceiling out of ground effect: 10 m (33 ft) Avionics AP-44 autopilot VUAP-2 EXPERIMENTAL AUTOPILOT ROZ-1 Lotsiya weather and navigational radar
Posted on: Thu, 08 Jan 2015 17:54:26 +0000
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