The third of Mikhail Mil's current quartet of turbine-powered helicopters, the Mi-8, appeared in prototype form towards the end of 1961. In broad terms it bears the same relationship to the Mi-4 as the Mi-2 has to the Mi-1, and (initially at least) the rotor hub, rotor blades, rear fuselage boom and certain undercarriage components were similar to those employed in the Mi-4. The original prototype was powered by a single 2700shp Soloviev shaft turbine mounted over the cabin roof, but in the second machine, which flew for the first time on 17 September 1962, this was replaced by two of the smaller Isotov engines of 1500shp each. The latter has been the standard installation on all subsequent aircraft, the only major design change being the substitution of a 5-blade rotor for the original 4-blade one in 1964.

Intended primarily for Aeroflot, the Mi-8 carries a 2- or 3-man crew and has seating accommodation for up to 28 passengers in its standard airline form. Alternative internal arrangements include a de luxe saloon cabin for executive travel or a cargo layout for an internal payload of 4000kg. Emergency conversion of the cargo model to a passenger carrier can be carried out quickly by installing 24 tip-up seats along the cabin sides. Clamshell rear doors are provided for loading large items of cargo or, in the ambulance role, 12 stretchers which can be carried with an accompanying medical attendant.

Like the other Mil turbine helicopters, the Mi-8 can also be used as a rescue machine with a winch on the cabin side capable of lifting a 250kg load, or with an under-fuselage hook for an external sling load of about 2500kg.

K.Munson "Helicopters And Other Rotorcraft Since 1907", 1968

Designed originally in 1960, the V-8 'Hip-A' prototype helicopter was basically a turbine-powered version of the Mi-4, retaining initially its rotor, transmission and a number of other components. Intended powerplant was two Isotov turboshaft engines, but as these were not fully developed when the V-8 was nearing completion, it was powered instead by a single large Soloviev turboshaft derated to the 2013kW limit of the transmission, for its first flight in June 1960. However, the second machine (flown for the first time on 17 September 1962) introduced the Isotov engines, each then rated at 1119kW, and this became the standard installation on early production aircraft, designated Mil Mi-8 (NATO reporting name 'Hip'). The only other major change to be introduced since that time resulted from problems with the main rotor inherited from the Mi-4, replaced in 1964 by a five-bladed rotor of more advanced design in the 'Hip-B' prototype. The availability of so much engine power, by comparison with the 1268kW of the Mi-4, meant the new helicopter had a larger cabin, providing accommodation for a crew of two or three and up to 28 passengers in a standard airline configuration. Since series construction began, a total of 10,000 Mi-8s have been built, for both civil and military use. Some components are built in China.

Large numbers of Mi-8s are used by Aeroflot in the transport role, being deployed also for ice reconnaissance, rescue operations and logistic support, but even greater numbers are operated by the Soviet Union's Frontal and Naval Aviation and, in addition, these helicopters have been supplied to the armed forces of about 40 other nations. The military versions are identified usually by their NATO reporting names.

Variants

Mi-8: standard production passenger version, accommodating 28 to 32 passengers

Mi-8T: utility civil transport, intended primarily for the carriage of internal or external freight, but able to accommodate 24 passengers on sidewall tip-up seats

Mi-8 Salon: de luxe civil transport with optional nine- and 11-seat interiors

'Hip-C': military assault transport with external stores racks on each side of cabin for 128 rockets or other weapons; some uprated to Mi-17 standard as Mi-8T and Mi-8TB, with port-side tail rotor

'Hip-D': airborne communications version

'Hip-E': heavily-armed attack helicopter, with 12.7mm machine-gun in nose, external racks for up to 192 rockets and four AT-2 'Swatter' anti-tank missiles

'Hip-F': export version generally similar to 'Hip-E' but with six AT-3 'Sagger' ATMs

'Hip-G': communications-relay model

'Hip-H': updated Mi-8 with uprated engines giving improved performance; redesignated Mi-17

'Hip-J’: ECM version

‘Hip-K': ECM jammer version with antenna array on each side of boom; some uprated to Mi-17 standard, with port-side tail rotor.

D.Donald "The Complete Encyclopedia of World Aircraft", 1997

Development began May 1960, to replace piston-engined Mi-4; first prototype, with single AI-24V turboshaft and four-blade main rotor, flew June 1961, given NATO reporting name 'Hip-A'; second prototype ('Hip-B'), with two production standard TV2-117 engines and five-blade main rotor, flew August 1962; more than 10,000 Mi-8s, Mi-17s and Mi-171s marketed and delivered from Kazan (Mi-8, Mi-17, Mi-172) and Ulan-Ude (Mi-8T, Mi-171) plants for civil and military use, including 2,800 exported; many Mi-8s converted to Mi-17 standard.

VERSIONS

Mi-8APS: Military VIP transport with enhanced communications fit and more luxurious interior; used as Russian Presidential aircraft.

Mi-8AT: Civil transport version produced by Ulan-Ude; TV2-117AG turboshafts; optional 8A-813 weather radar, DISS-32-90 Doppler radar and A-723 long-range radio navigation.

Mi-8ATS: Agricultural helicopter with spray hoppers on each side, and with 'wing'-type spraybars.

Mi-8AV: Dedicated minelayer, despatching mines down steep, ladder-like slide projecting from gap between lower corners of clamshell doors.

Mi-8BT: Equipped for minesweeping, towing sled from winch in cabin. Clamshell doors removed for missions.

Mi-8K: Reconnaissance and artillery fire correction version; large window for camera in rear clamshell doors.

Mi-8MT: Flying crane version with operator's glazed gondola in place of rear clamshell doors. SSSR-254444 may have been the prototype. Designation re-used for Mi-17.

Mi-8P ('Hip-C'): Civil passenger helicopter; standard seating for 28 to 32 persons in main cabin with large square windows.

Detailed description refers to this version, except where indicated.

Mi-8PD (punkt dowodzenia): Polish airborne command post version.

Mi-8PPA ('Hip-K'): Active communications jammer; rectangular container and array of six cruciform dipole antennae each side of cabin; no Doppler box under tailboom; heat exchangers under front fuselage; some uprated to Mi-17 standard, with port-side tail rotor.

Mi-8PS ('Hip-C'): Military VIP transport; basically as civil Mi-8 Salon.

Mi-8R: Reconnaissance version.

Mi-8S (Salon) ('Hip-C'): Original de luxe version of standard Mi-8; normally 11 passengers, on eight-place inward-facing couch on port side, two chairs and swivelling seat on starboard side, with table; square windows; air-to-ground radiotelephone and removable ventilation fans; compartment for attendant, with buffet and crew wardrobe forward of cabin; toilet (port) and passenger wardrobe (starboard) to each side of cabin rear entrance; alternative nine-passenger configuration; maximum T-O weight 10,400kg; range 380km with 30 minutes fuel reserve.

Mi-8SMV ('Hip-J'): ECM version with R-949 jamming system; additional small boxes each side of fuselage, fore and aft of main landing gear legs. Also four containers with 32 droppable short-range jammers. Range 54 n miles (100 km; 62 miles).

Mi-8T ('Hip-C'): Civil utility transport version, with TV2-117A turboshafts and circular cabin windows, built by Ulan-Ude plant. Alternative payloads include internal or external freight; 24 passengers on removable folding seats; 26 passengers on conventional seats; 12 stretcher patients or executive layout similar to Mi-8S.

Mi-8T ('Hip-C'): Also available as standard assault transport of Russian Federation and Associated States (RFAS) army support forces; carrying 24 fully armed troops. Able to dispense 200 anti-personnel or anti-tank mines in flight, by conveyor belt through rear doors.

Mi-8TB ('Hip-E'): Development of 'Hip-C'; KV-4 flexibly mounted 12.7 mm machine gun, with 700 rounds, in nose; triple stores rack each side, to carry total 192 S-5 rockets in six UV-32-57 packs, plus four 9M17P Scorpion (AT-2 'Swatter') anti-tank missiles (semi-automatic command to line of sight) on rails above racks; about 250 in RFAS ground forces; some uprated to Mi-17 standard as Mi-8MTV, with port-side tail rotor.

Mi-8TBK ('Hip-F'): Export 'Hip-E'; missiles changed to six 9M14 Malyutka (NATO AT-3 'Saggers'; manual command to line of sight).

Mi-8TG: Modified TV2-117TG engines permit operation on Liquefied Petroleum Gas (LPG) and Kerosene. LPG contained in large tanks, on each side of cabin, under low pressure. Engines switch to Kerosene for take-off and landing. Reduced harmful exhaust emissions in flight offer anti-pollution benefits. Modification to operate on LPG requires no special equipment and can be effected on in-service Mi-8s at normal maintenance centre. Weights unchanged. Large external tanks, each side of cabin, reduce payload by 100 to 150kg over comparable ranges, with little effect on performance. First flight on LPG made 1987.

Mi-8T(K) : Dedicated photo-reconnaissance platform with AFA-42/100 or AFA-A87P starboard oblique camera in forward part of the cabin, possibly with some onboard processing capability. May be used as fire correction platform.

Mi-8TM : Upgraded civil transport version of Mi-8T; weather radar and rotor head integrity system.

Mi-8TP : Military executive version; upgraded communications include R-832 radio with two-blade antennae under front fuselage and tailboom and R-111 with rod antenna lowered under cabin.

Mi-8TS (tropichesky sukhoi: tropical): Export version for hot and dusty climates.

Mi-8TV (vooruzhonnyi: armed) ('Hip-C'): As Mi-8T, but with added twin-rack each side, to carry total of 64 57 mm S-5 rockets in four UV-16-57 packs, or bombs, for army assault forces.

Mi-8TZ: Adapted to deliver fuel to front-line areas.

Mi-8 VIP: Current de luxe version by Kazan; three crew and seven to nine passengers; main rotor has vibration damper; hinged airstair door; interior divided into vestibule, passenger cabin crew department, cloakroom and toilet; optional water heater, TV and GPS. Maximum take-off weight 12,000kg.

Mi-8VZPU (vozduzhnyi zapasnoi punkt upravlenya: airborne reserve command post) ('Hip-D'): As 'Hip-C' but rectangular-section canisters on outer stores racks; two large dorsal antennae above forward part of tailboom; no armament.

Mi8AMT, Mi-8MT and Mi-8MTV are versions of the Mi-17, with more powerful turboshafts and port-side tail rotor.

All helicopters of Mi-8/Mi-17 series in Russian military service are known as Mi-8s of various subtypes, regardless of engines fitted.

Mi-9 ('Hip-G'): Airborne command post variant of Mi-8; 'hockey stick' antennae projecting from rear of cabin and from undersurface of tailboom, aft of Doppler radar box; rearward inclined short whip antenna above forward end of tailboom; strakes on fuselage undersurface. Crew of three to six.

Long-range modification: AEFT (Auxilliary External Fuel Tanks) by Aeroton adds another 1,900 litres in two internal tanks, plus same quantity in four external tanks on the stores pylons of the Mi-8T and Mi-8AT. Operational range with all six tanks is 1,100km; ferry range 1,600km.

CUSTOMERS: RFAS ground forces (estimated 2,400 Mi-8/17s); RFAS air forces; at least 40 other air forces; civil operators worldwide.

DESIGN FEATURES: Conventional pod and boom configuration; five-blade main rotor, inclined forward 4° 30' from vertical; interchangeable blades of basic NACA 230 section, solidity 0.0777; spar failure warning system; drag and flapping hinges a few inches apart; blades carried on machined spider; pendulum vibration damper; three-blade starboard tail rotor; transmission comprises VR-8 two-stage planetary main reduction gearbox giving main rotor shaft/engine rpm ratio of 0.016:1, intermediate and tail rotor gearboxes, main rotor brake, and drives off main gearbox for tail rotor, fan, AC generator, hydraulic pumps and tachometer generators; tail rotor pylon forms small vertical stabiliser; horizontal stabiliser near end of tailboom; clamshell rear-loading freight doors.

FLYING CONTROLS: Mechanical system, with irreversible hydraulic boosters; main rotor collective pitch control linked to throttles.

STRUCTURE: All-metal; main rotor blades each have extruded light-alloy spar carrying root fitting, 21 honeycomb-filled trailing-edge pockets and blade tip; balance tab on each blade; each tail rotor blade made of spar and honeycomb-filled trailing-edge; semi-monocoque fuselage.

LANDING GEAR: Non-retractable tricycle type; steerable twin-wheel nose unit, locked in flight; single wheel on each main unit; oleo-pneumatic (gas) shock-absorbers. Mainwheel tyres 865 x 280mm; nosewheel tyres 595 x 185mm. Pneumatic brakes on mainwheels; pneumatic system can also recharge tyres in the field, using air stored in main landing gear struts. Optional mainwheel fairings.

POWER PLANT: Two 1,250kW Klimov TV2-117A turboshafts (1,434 kW TV3-117MTs in Mi-8MT). Main rotor speed governed automatically, with manual override. Single flexible internal fuel tank, capacity 445 litres; two external tanks, each side of cabin, capacity 745 litres in port tank, 680 litres in starboard tank; total standard fuel capacity 1,870 litres. Provision for one or two ferry tanks in cabin, raising maximum total capacity to 3,700 litres. Fairing over starboard external tank houses optional cabin air conditioning equipment at front. Engine cowling side panels form maintenance platforms when open, with access via hatch on flight deck. Total oil capacity 60kg.

ACCOMMODATION: Two pilots side by side on flight deck, with provision for flight engineer's station. Military versions can be fitted with external flight deck armour. Windscreen de-icing standard. Basic passenger version furnished with 24 to 26 four-abreast track-mounted tip-up seats at pitch of 72 to 75cm, with centre aisle 32cm wide; removable bar, wardrobe and baggage compartment. Seats and bulkheads of basic version quickly removable for cargo carrying. Mi-8T and standard military versions have cargo tiedown rings in floor, winch of 150kg capacity and pulley block system to facilitate loading of heavy freight, an external cargo sling system (capacity 3,000kg), and 24 tip-up seats along sidewalls of cabin. All versions can be converted for air ambulance duties, with accommodation for 12 stretchers and tip-up seat for medical attendant. Large windows on each side of flight deck slide rearward. Sliding, jettisonable main passenger door at front of cabin on port side; electrically operated rescue hoist (capacity 150kg) can be installed at this doorway. Rear of cabin made up of clamshell freight-loading doors, which are smaller on commercial versions, with downward-hinged passenger airstair door centrally at rear. Hook-on ramps used for vehicle loading.

SYSTEMS: Standard heating system can be replaced by full air conditioning system; heating of main cabin cut out when carrying refrigerated cargoes. Two independent hydraulic systems, each with own pump; operating pressure 44 to 64 bars. DC electrical supply from two 27V 18kW starter/generators and six 28Ah storage batteries; AC supply for automatically controlled electrothermal de-icing system and some radio equipment supplied by 208/115/36/7.5V 400Hz generator, with 36V three-phase standby system. Engine air intake de-icing standard. Provision for oxygen system for crew and, in ambulance version, for patients. Freon fire extinguishing system in power plant bays and service fuel tank compartments, actuated automatically or manually. Two portable fire extinguishers in cabin.

AVIONICS: Comms: R-842 HF transceiver, frequency range 2 to 8MHz and range up to 1,000km; R-860 VHF transceiver on 118 to 135.9MHz effective up to 100km, intercom, radiotelephone.
Flight: Four-axis autopilot to give yaw, roll and pitch stabilisation under any flight conditions, stabilisation of altitude in level flight or hover, and stabilisation of preset flying speed; Doppler radar box under tailboom.
Instrumentation: For all-weather flying by day and night: two gyro horizons, two airspeed indicators, two main rotor speed indicators, turn indicator, two altimeters, two rate of climb indicators, magnetic compass, astrocompass for Polar flying; ARK-9 automatic radio compass, RV-3 radio altimeter with 'dangerous height' warning.
Self-defence (optional): Infra-red jammer ('Hot Brick') above forward end of tailboom; three ASO-2V flare dispensers above rear cabin window on each side.

ARMAMENT: See individual model descriptions of military versions.

Jane's Helicopter Markets and Systems

- More than 10,000 Mi-8s and Mi-17s have been built, with many hundreds being exported to more than 40 operators.

- The Mil Mi-17 is basically a Mi-8 with more power and a new tail rotor.

- The rare Mi-8PPA is a special communications jammer variant.

- The Mi-8 has fought in Afghanistan, Angola, Chechnya, Egypt, Mozambique and Nicaragua.

- The Czech Republic, Hungary and Russia use the 'Hip-G' command post version.

- The Mil Mi-14 'Haze' anti-submarine helicopter is derived from the Mi-8.