Mil Mi-10 "Harke"

Mil Mi-10 "Harke"

The Mil Mi-10 (NATO reporting name Harke), given the product number izdeliye 60, was a Soviet military transport helicopter of flying crane configuration, developed from the Mi-6, entering service in 1963.

The advent of the Mi-6 gave the Soviet Union the very useful ability to move and place large, bulky or heavy loads with precision. Limitations of the Mi-6 in the flying crane role included a weight to payload ratio and the inability of the crew to easily see the load and its intended final position. A Council of Ministers directive of 20 February 1958 tasked OKB-329 (OKB Mil) with the development of a dedicated flying crane helicopter for carrying bulky loads unable to be carried in the hold of a Mi-6. The Mil OKB's response drew heavily on the Mi-6, utilising the dynamic components and 4,100 kW (5,500 hp) Soloviev D-25V turboshaft engines, on a slim fuselage sitting on four tall strut braced undercarriage legs, with a wide track allowing the helicopter to taxi over loads, or for mobile loads to be moved underneath. The fuselage can carry 28 passengers inside the cabin as well as 3 t (3,000 kg; 6,600 lb) of cargo loaded through a side door in the aft fuselage, by an integral boom and winch. Underslung loads can be attached directly to the fuselage by hydraulically operated clamps, or carried on a 8.5 m × 3.6 m (28 ft × 12 ft) pallet lifted by the winch and braced by cables and/or struts to the undercarriage legs. The external sling system, with a capacity of 8 t (8,000 kg; 18,000 lb), of the Mi-6 could also be fitted under the centre fuselage.

The first prototype V-10 emerged with canted main undercarriage legs with single wheels on all four legs, as well as a retractable emergency escape chute extending below the cockpit and external auxiliary fuel tanks either side of the centre fuselage. As development progressed the main undercarriage legs were replaced with vertical units carrying twin wheels, twin nose undercarriage wheels after a period retaining the single wheels, an Auxiliary power unit (APU) installed behind the cockpit on the starboard side and emergency escape slide cables for use when the pallet is carried. The first prototype V-10 was completed in 1959 and was soon allocated the service designation Mi-10. The first flight took place on 15 June 1960 and flight testing continued successfully until in May 1960 the first prototype crashed during a precautionary landing resulting from loss of gearbox oil pressure, only the Navigator/ radio operator surviving. After joining the flight test programme the second prototype began a series of world record breaking altitude/payload flights for turbine powered helicopters. State acceptance trials were passed successfully in 1961, but production did not commence until 5 March 1964 at the Rostov-on-Don factory, with first flight of a production aircraft on 10 September 1964, leading to a total of forty of the long-legged Mi-10 helicopters built, from 1964 to 1969.

The operational service of the Mi-10 was of moderate success, being distributed mainly to units of the VVS (Voyenno-Vozdushnyye Sily - Soviet Air Force) which already operated the Mi-6. Operations with no load were found to be unstable, and the best procedure for take-off was found to be a rolling take-off, which usually also resulted in nose-wheel shimmy when lightly loaded. The main mission of the early Mi-10 virtually evaporated with the improvements in contemporary ballistic missiles; thus the majority of the long-legged variants were converted to Mi-10PP, (or mi-10P), airborne Electronic Counter-Measures helicopters, carrying a large ST-900 Step' (Step' - Steppe) ECM pod under the fuselage mounted on a pallet.[1] Other Mi-10 long legged aircraft were converted to carry out a wide variety of missions but usually only as single prototypes. Of special note was the Mi-10R (R - recordnyy- record) record breaking helicopter, converted from a production machine, with the undercarriage of a Mi-6 fitted with fairings and spats, as well as a tail bumper to reduce the risk of damage to the rear fuselage on landing. Other variants are noted or described below in the variants section.

General characteristics

• Crew: 4 or 5 (pilot, copilot, flight engineer, navigator/radio operator and optional technician)
• Capacity:
  
  • 28 passengers or
  • 3 t (3,000 kg; 6,600 lb) internally
  • up to 15 t (15,000 kg; 33,000 lb) payload on platform or
  • 8 t (8,000 kg; 18,000 lb) max slung payload
• Length: 32.86 m (107 ft 10 in) , Mi-10K 32.4 m (106 ft) ignoring rotors
• Empty weight: 27,100 kg (59,745 lb) , Mi-10K 25,450 kg (56,100 lb)
• Gross weight: 43,550 kg (96,011 lb) , Mi-10K 37,000 kg (82,000 lb)
• Max takeoff weight: 43,700 kg (96,342 lb) , Mi-10K 38,000 kg (84,000 lb)Ground clearance under fuselage: 3.75 m (12.3 ft)
• Powerplant: 2 × Soloviev D-25V turboshaft, 4,100 kW (5,500 hp) each
• Main rotor diameter: 35 m (114 ft 10 in)
• Main rotor area: 962 m² (10,350 sq ft)

Performance

• Maximum speed: 335 km/h (208 mph; 181 kn) , Mi-10K 350 km/h (220 mph; 190 kn)
• Cruising speed: 180 km/h (112 mph; 97 kn) , Mi-10K 228 km/h (142 mph; 123 kn)
• Range: 430 km (267 mi; 232 nmi) , Mi-10K 500 km/h (310 mph; 270 kn)
• Disk loading: 45.27 kg/m² (9.27 lb/sq ft) , Mi-10K - 38.46 kg/m² (7.87 lb/sqft) at normal AUW
• Hovering ceiling out of ground effect: Mi-10 3,000 m (9,800 ft), Mi-10K 1,000 m (3,300 ft)
• Hovering ceiling in ground effect: Mi-10K 3,000 m (9,800 ft)
• Dynamic ceiling: Mi-10K 4,750 m (15,580 ft)