[1.0] Mi-8 Variants (original) (raw)
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v1.1.1 / chapter 1 of 2 / 01 may 10 / greg goebel / public domain
* The Mi-8 series has been produced in a wide number of variants, running through three generations, with development continuing in the 21st century. This chapter outlines the evolution of the Mi-8 series.
[1.1] MI-8 ORIGINS
[1.2] MI-8T DESCRIBED / MI-8TV
[1.3] MILITARY MI-8 VARIANTS
[1.4] CIVIL MI-8 VARIANTS
[1.5] SECOND-GENERATION MI-8MT
[1.6] MI-8 SERIES IN THE POST-SOVIET ERA
[1.1] MI-8 ORIGINS
* The design bureau under Mikhail Lyeontivich Mil was responsible for several early Soviet helicopters, including the piston-powered "Mi-1 Hare" and larger "Mi-4 Hound", leading to the turboshaft-powered heavy-lift "Mi-6 Hook". In 1957, the Mil OKB began to consider a successor to the medium-lift Mi-4, powered by twin turboshaft engines. At the time, there was for various reasons a bias against the development of new aircraft types, and so the new machine was sold as an "upgrade" of the Mi-4 -- which was something of a stretch, it was basically a new design, but it did leverage off the Mi-4's tailboom, rotor system, landing gear, and so on.
In February 1958, the Soviet Council of Ministers guardedly approved the plan. The ministers authorized development of a medium-lift helicopter, with the OKB designation of "V-8" -- where "V" stood for "vertolyot (helicopter)" -- to be powered by a single Ivchenko Al-24V turboshaft engine, providing 1,420 kW (1,900 SHP). The Al-24V was a derated turboshaft version of the 1,790 kW (2,400 SHP) Al-24 turboprop then in development for the Antonov An-24 twin-engine transport aircraft.
Mil OKB engineers were not at all happy with the requirement to use a single engine since it compromised safety, and also did not like the fact that the Al-24V was a fuel hog. Mikhail Mil lobbied the authorities to approve parallel development of a twin-engine version, pointing out that the machine would be used as a VIP transport and that it would be unwise to compromise the safety of Soviet leadership. The appeal to self-interest proved successful; after preliminary designs and a full-scale mockup were inspected, approval for the twin-engine "V-8A" was given in May 1960. There were the problems that no appropriate turboshaft engine actually existed to power the V-8A and that twin engines would require a new main gearbox to mesh their output power, but the Isotov engine OKB came on board to design a new turboshaft, the TV2, with a power rating of 930 kW (1,250 SHP) and also to implement the two-into-one gearbox.
The single-engine V-8 was the first to fly, performing its initial flight on 24 June 1961, with test pilot Boris V. Zemskov. This machine had the rotor system and other elements taken direct from the Mi-4 -- the engineers actually wanted to improve on Mi-4 based components, but that would take a bit of time, and Mil wanted to get the machine flying quickly. It was configured as a passenger liner, with 18 seats and rectangular windows, and also had mainwheel spats, which would not be featured in production machines.
The V-8 was displayed to the world on 9 July 1961 at the Moscow Tushino Airport airshow, with NATO assigning the type the codename "Hip", to become "Hip-A" after other versions appeared. By the time the V-8 took to the air, whatever interest there had been in putting it into production had generally faded out, and it was simply used as a test rig, finally being grounded in 1963 and later scrapped. Two other V-8 prototypes were built but they never flew, being used as ground-test airframes.
Initial full flight of the first prototype of the twin-engine V-8A was on 17 September 1961, with test pilot V.N. Loshkin at the controls. As it initially flew, it was very similar to the V-8 -- 18 seat heliliner configuration with mainwheel spats and four-bladed rotor -- except for twin TV2 turboshafts. It was gradually fitted with new kit as it became available, particularly a five-bladed rotor leveraged from the Mi-4 four-bladed rotor, bringing the machine closer to production spec. When NATO became aware of the V-8A, it was assigned the codename "Hip-B". This prototype served faithfully as a development platform until it crashed in January 1966, killing all three crew on board.
Two more initial V-8A series flight prototypes were built, including the "V-8AT" military assault transport prototype, and the "V-8AP" VIP transport. The V-8AT performed its initial flight in the summer of 1963; although it had a military configuration and good military green paintjob, it retained rectangular windows of the heliliner configuration. It was temporarily modified the next spring, 1964, to a VIP transport configuration to act as a demonstrator for the V-8AP, which performed its own initial flight in the spring of 1964. It was later modified to a heliliner configuration.
The trials went very well, with the V-8A prototypes demonstrating that they had twice the lift capability and 50% more speed than the Mi-4, and were three times as economical to operate. The military version was ordered into production as the "Mi-8T" in the fall of 1964, with the heliliner version authorized as the "Mi-8P" in the spring of 1965. Both were assigned the NATO codename of "Hip-C". Initially, production was assigned to State Factory 387 in Kazan, now capitol of the Republic of Tatarstan. Factory 387 was already building the Mi-4 and the first Mi-8s began rolling off the production line in late 1965. In 1970, with demand for the Mi-8 running high, State Factory 99 at Ulan-Ude in Siberia also would begin production of the type.
The "Hip" was in fact an outstanding machine, an example of Soviet engineering at its best: sturdy, reliable, easy to maintain and operate, capable, and relatively inexpensive. It would prove to be one of the most important helicopters ever built.
[1.2] MI-8T DESCRIBED / MI-8TV
* Although the Mi-8 family would undergo considerable evolution during its lifetime -- in fact, it is still evolving -- the Mi-8T provides a useful baseline for the time.
The Mi-8T was built mostly of aircraft aluminum, with a bus-like body slung under an engine assembly consisting of twin Isotov TV2-117A turboshafts, trailed by a tail boom. Each engine provided 1,120 kW (1,500 SHP) max but the rotor system couldn't tolerate the full power of both engines, and so there was a limiter system to restrict engine output power; however, if one engine went down the other could then operate at full rated power. The engine inlets featured a de-icing system using hot engine bleed air.
Later production had uprated TV2-117F engines with 1,268 kW (1,700 SHP) each, to be followed in turn by TV2-117AG engines with the same ratings but lower cost and greater reliability, partly thanks to graphite seals. It is very difficult to determine exactly which variants of the Mi-8 were fitted with which TV2 engine variant, all the more so because it's very possible some early machines were upgraded to improved engines over their service lives.
The engine service doors hinged down and were sturdy enough to be used as work platforms when open, a common gimmick among Mil helicopters. There was an access hatch in the roof of the cargo bay to allow service personnel to climb on top of the helicopter.
The main rotor system had five blades, while the tail rotor had three, with the tail rotor mounted to the right. All the rotor blades were made of metal and featured an electrothermal de-icing system. A tailplane was fitted forward of the tail rotor, and most (though not all) Mi-8T production had a boxy fairing underneath the tailboom for a Doppler speed sensor. The tailboom could be detached with relative ease for transport or storage.
Tricycle landing gear was fitted, with the castoring nose gear featuring two wheels and the main gear featuring one wheel each; the main gear was mounted on shock-absorbing tripod frames. Steering while taxiing was by differential braking. The mainwheel spats fitted to prototypes were deleted in production machines. Fuel storage was in external fuel tanks, one on each side of the fuselage forward of the main landing gear; initially, fuel capacity was 745 liters (196 US gallons) for the left-side tank and 680 liters (179 US gallons) for the right-side tank, but late production featured enlarged tanks with 1,140 liters (301 US gallons) and 1,030 liters (272 US gallons) respectively. The right-side external tank had an extended fairing on the nose to accommodate a cabin heating system. There was also a reserve tank with a capacity of 445 liters (117 US gallons) mounted behind the main gearbox, and twin ferry tanks with a capacity of 915 liters (241 US gallons) could be temporarily fitted in the cabin.
The pilot and copilot sat side-by-side in the nose, with a jump seat for a flight engineer behind them; the cockpit was separated from the cargo bay by a bulkhead with a door. Although consideration had been given in the design phase to a "stepped" nose like that of the big Mi-6, as developed the Mi-8 had a glassed-in front that gave it a "snubbed nose" appearance. The three main windshield panels were made of glass -- the others were Perspex -- and were electrically deiced, with the pilot's and copilot's panels also featuring a windshield wiper. The (sliding) cockpit side windows were bulged to give the aircrew a better view back and down. There had been an additional small lower window under the side windows in the prototypes, but it was deleted in production.
There was a sliding entry door with fold-down steps behind the cockpit on the left, with provision for mounting a rescue hoist above the door. The standard configuration included 24 tip-up seats alongside the cargo bay walls for troop transport, though this configuration could be changed to a medevac configuration with 12 stretchers and one tilt-down seat for a medical attendant. There were circular portholes along each side of the fuselage that could be tilted in and up to be locked in open position, allowing troops to fire their weapons from mounts fitted to the porthole frames.
Clamshell doors were fitted at the rear for freight loading, with an escape hatch in one door. Twin hook-on ramps were carried to allow vehicles to drive in; an integral ramp had been featured in prototype development, but the integral ramp wasn't always a benefit: when loading from the back of a truck, it was easier to get rid of the ramps and just back the truck up to the rear of the helicopter.
The cargo bay had a length of 5.34 meters (17 feet six inches), a width of 2.3 meters (7 feet 6 inches), and a height of 1.82 meters (6 feet). There were cargo tie-downs on the floor and an electric hoist system in the ceiling with load capacity of 200 kilograms (440 pounds). Maximum internal cargo capacity was 4,000 kilograms (8,800 pounds), with loads including light vehicles, artillery pieces, and the like. Twin ferry tanks could be installed in the cargo bay. There was an external sling system underneath the helicopter with a capacity of 3,000 kilograms (6,600 pounds) for carrying loads too bulky to fit in the cargo bay.
MIL MI-8T "HIP-C": _____________________ _________________ _______________________
spec metric english _____________________ _________________ _______________________
main rotor diameter 21.29 meters 69 feet 10 inches tail rotor diameter 3.8 meters 12 feet 6 inches fuselage length 18.31 meters 60 feet footprint length 25.35 meters 83 feet height (tail rotor) 5.54 meters 18 feet 2 inches height (rotor head) 4.76 meters 15 feet 7 inches
empty weight 7,160 kilograms 15,785 pounds max loaded weight 12,000 kilograms 26,455 pounds
maximum speed 250 KPH 155 MPH / 135 KT service ceiling 4,500 meters 14,760 feet range 425 kilometers 265 MI / 230 NMI _____________________ _________________ _______________________
Performance specifications are given for normal loaded weight.
* The Mi-8T was designed from the outset to carry armament, though the machine wasn't actually available in armed form until 1968. It could be fitted with the weapons outrigger system from the Mi-4AV, with twin stores racks on either side, typically carrying a total of four 16-round 57 millimeter unguided rocket pods, targeted by a sight fitted in the cockpit. Bombs of up to 500 kilograms (1,100 pounds) each could also be carried, though that seems to have been an unusual fit. The lower forward cockpit window could be replaced with a panel featuring a swivel mount for a 7.62 millimeter Kalashnikov PKT machine gun. The armed version was eventually referred to as the "Mi-8TV" -- where the "V" stood for "voruzhonniy (armed)" -- but it wasn't at all different from any other Mi-8T except for the weapons kit, and any Mi-8T could be easily equipped with the same armament configuration. NATO still gave it the "Hip-C" codename.
In 1974, the Kazan plant decided to "up-arm" the Mi-8TV. The "Mi-8TV-2" -- an informal designation, the improved machine was still an Mi-8TV -- featured a new armament system with three stores racks on either side, capable of carrying heavier loads, generally a 32-round 57 millimeter rocket pod, providing a total of six pods and 192 rockets. A total of four 9M17P Falanga-P (NATO AT-2 Swatter-C) anti-tank rockets could be mounted on top of the outrigger as well, with the helicopter fitted with a radio link to control the missiles and the copilot directing them with a gyrostabilized sight.
The nose-mounted machine gun was retained. The fuel tanks were filled with polyurethane foam to improve combat survivability. A similar "Mi-8TVK" was built for export, differing only in replacing the four Falanga-Ps with six wire-guided 9M914M Malyutka (NATO AT-3 Sagger) antitank missiles. NATO gave the up-armed Mi-8TV the codename "Hip-E", with the export model given the codename "Hip-F". It appears that Soviet practice was to use them generally as dedicated gunships, since when they had a full load of munitions they couldn't carry much else.
Note that late-production military Hip variants were sometimes fitted with chaff-flare dispensers, along with an "infrared countermeasures (IRCM)" beacon on the back behind the rotor system, to provide defense against heat-seeking missiles. As with engine fits, it is unclear which variants had countermeasures, or if they were refitted to older machines later.
[1.3] MILITARY MI-8 VARIANTS
* The Mil-8T was used as the basis for a set of tactical airborne command posts for battlefield operations, beginning with the "Mi-8VKP" AKA "Mi-8VZPU" -- the suffixes corresponded to different Russian phrasings of the term "airborne command post". All were refits of stock Mi-8Ts. They featured a nonstandard antenna fit to support command and control communications, most significantly twin outward-canted "towel rack" antennas above the end of the fuselage, as well as rectangular equipment boxes permanently fitted to the external stores outriggers. It received the NATO codename of "Hip-D".
The "Mi-8IV" AKA "Mi-9" was a purpose-built tactical airborne command post, using an airframe that had porthole windows like the Mi-8T but the clamshell door arrangement of the Mi-8P heliliners. It didn't have the external equipment boxes, but it did have a nonstandard antenna arrangement, most significantly long strake antennas under the fuselage. It went into production in the late 1970s, and received the NATO codename of "Hip-G".
* There was also a series of electronic countermeasures (ECM) "Hips", intended for the battlefield jamming mission. One of the first was the "Mi-8MV", which carried the "Smalt'a-V" ECM system to jam battlefield air-defense radars. It was a relatively discreet modification of the Mi-8T, the main distinguishing feature being loss of a forward window on each side to permit fit of a dielectric panel for ECM gear; a similar dielectric panel on each side of the fuselage forward of the rear clamshell doors; and a short wire antenna strung on two short stubs and running down the belly. It was given the NATO codename of "Hip-J". Mi-8MVs were often upgraded in service to improved ECM packages, sporting a slightly altered set of antennas.
The "Mi-8PP" was introduced more or less in parallel. It also was designed to jam air-defense radars, but it had a signals intelligence (SIGINT) function as well. It featured a "Pole (Field)" ECM system and was much more cluttered in appearance than the Mi-8MV, with each side of the machine featuring a box on the middle fuselage and a rectangular array of six X-shaped antennas in a two-rows-of-three arrangement on the rear fuselage. Since the ECM gear generated a lot of heat, there were six heat exchangers in fairings in a row underneath the fuselage. It was given the NATO codename of "Hip-K".
An improved version, the "Mi-8PPA", featured the improved "Akatsiya (Acacia)" ECM suite. It looked almost exactly like the Mi-8PP and was also referred to as the "Hip-K" by NATO.
* There was very wide range of military Mi-8 subvariants that were only made in small numbers:
- The "Mi-8MB" was a medical evacuation ("medevac") helicopter, with some specialized kit for handling survivors of a nuclear attack. It was introduced in the mid-1970s.
- A variant of the Mi-8T to lay antitank mines was developed and assigned the designation of "Mi-8AV" AKA "Mi-8VSM". It featured a chute run out the back doors to drop the mines. The chute shifted back and forth to ensure a distributed pattern; it could be tucked up under the tailboom in normal flight but it could not be stowed inside. A similar variant was introduced to sow antipersonnel mines and was designated "Mi-8AD".
- The "Mi-8R" AKA "Mi-8GR" was a battlefield reconnaissance variant, with large rear observation windows. There was another battlefield reconnaissance variant, the "Mi-8TG" AKA "Mi-8TARK" with a different equipment fit for artillery spotting, as well as an "Mi-8VD" reconnaissance variant specifically for radiation monitoring on a nuclear battlefield.
- Some Mi-8Ts were used for the search and rescue (SAR) mission after being fitted with a heavy-duty door hoist. These machines were confusingly known with the designation of "Mi-8PS", though that was more commonly used as the designation for civil-type executive transport heliliner versions of the "Hip", as discussed below.
- Two Mi-8Ts were modified as specialized SAR machines, being used to track down and recover Soyuz space capsules and their crews after they parachuted back to Earth. It seems likely that they also recovered capsules returned by unmanned Soviet space missions -- Soviet reconnaissance and Earth remote sensing satellites were generally designed to send a payload capsule back to Earth, and they did it often enough to keep recovery crews busy. These two "Hips" were designated "Mi-8SP"; they were later upgraded and redesignated "Mi-8SPA". At least one Mi-8 was converted to a command post version to direct spacecraft recovery operations, this subvariant being designated "Mi-8KP".
- The "Mi-8TZ" was a tanker, designed to fly out to the forward lines and refuel ground vehicles or other helicopters. It had no inflight refueling capability.
- The "Mi-8TL" was a fire-fighter, its primary kit being a sling-load "bucket" that it could fill with water from a lake and then dump on a fire. Apparently the Mi-8TL saw fairly extensive use.
- After the Mideast Ramadan / Yom Kippur War of 1973, five Mi-8Ts were converted on a fast-track basis as aerial minesweepers to help clear the Suez Canal. These machines were designated "Mi-8BT" and had the gear to handle and tow a minesweeping sled. They were later used as trials machines for the Mi-14BT "Haze-B" naval minesweeping helicopter, discussed later. There are also hints that some Mi-8Ts were converted to an antisubmarine warfare (ASW) configuration, but this is difficult to confirm.
- A number of Mi-8Ts were fitted out as battlefield communications relay platforms, but details are obscure. Other obscure variants include Mi-8Ts fitted out for the Border Guards and the Ministry of the Interior; crop sprayer variants, the "Mi-8ATS" and the "Mi-8FSkh", that didn't go into production, the "Hip" simply being too much helicopter for the job; a flying maintenance shop, the "Mi-8TECh-24", intended for frontline helicopter maintenance, which also didn't go into production; and a "psychological warfare" version, equipped with loudspeakers, that was employed in some numbers.
There were a number of one-off modifications as well. One Mi-8T was modified to set a world speed record for its class of 273 KPH (170 MPH) on 23 August 1967, flying with an all-woman crew. This machine featured spats on the mainwheels and no external fuel tank pods, all fuel storage being moved inside. There was an interest in a high-speed "compound helicopter" to be designated the "Mi-8S", with stub wings and auxiliary turbojets, but it didn't happen.
The modifications included a number of trials machines, sometimes referred to with the designation of "Mi-8LL". The "LL" suffix means "Letauschchaya Laboratoriya / Flying Laboratory" and was commonly applied to trials machines of all sorts, though sometimes they were assigned specific designations or no particular new designation. Trials "Hips" were used to evaluate "flying crane" systems; night vision systems; laser target designators; and even to propulsion with liquid hydrogen and liquefied natural gas. Finally, there were conversions to perform geophysical and environmental surveys, and even one set up to perform on-site air accident investigations.
[1.4] CIVIL MI-8 VARIANTS
* As mentioned specific civil heliliners and the like were built as well. The Mi-8P passenger helicopter variant -- such machines built in Ulan-Ude were designated "Mi-8AP" -- was very similar to the military variant, with the same performance and load limits. The major distinguishing characteristic was rectangular windows instead of portholes; there were also emergency exits on each side of the fuselage at the rearmost window position. Clamshell doors were retained, though they were smaller and there was a passenger door nested into them. Standard seating was 28 seats, though 26-, 24-, and 20-seat layouts were eventually adopted as well. The seats could be yanked to permit cargo carriage, and of course sling loads could be carried even if the seats were retained.
The Mi-8P was the basis for the "Mi-8PS" VIP transport variant, with the "S" standing for "Salon" -- Ulan-Ude machines were designated "Mi-8APS", incidentally. The Mi-8PS was very similar to the M-8P, but which was configured with luxury accommodations for 11, 9, or 7 passengers -- the different configurations sometimes being distinguished by the designations "Mi-8PS-11", "Mi-8PS-9", and "Mi-8PS-7" respectively. The "Mi-8APS" was an Mi-8PS built at Ulan-Ude.
The Mi-8P also led to the "Mi-8S" VIP transport, which visibly differed from the Mi-8P in fit of an air-conditioning system as a forward extension of the left-side fuel tank, matching the heater system extension on the right. This led to replacement of the sliding door (which no longer had any place to slide to) with a fold-down door featuring integral stairs. A secure communications system was added. Interior fit and accommodations was semi-custom, essentially installed at customer request. In reality, the distinction between the Mi-8PS and Mi-8S was never very clear, with some Mi-8PS machines featuring the folding door and air conditioner, while some Mi-8S machines featured the sliding door and did without the air conditioner.
* Sources confusingly indicate that the Mi-8T military version of the Hip was also used in the civil utility role, though this is doubly confusing because in many cases flying machines assigned to Aeroflot, the state airline, were actually used by the military and were not all that different from military-spec machines. They all had round windows. For what it's worth, the list included:
- The "Mi-8TP" was essentially an Mi-8T that could be fitted with decent passenger seats instead of the tip-up seats of a standard troop transport. It was fitted with TV2-117AG engines as well as an enhanced communications suite, and went into relatively widespread service.
- The "Mi-8AT" appears to have been the Mi-8TP, but built at the Ulan-Ude plant in Siberia.
- Some very late Ulan-Ude Mi-8AT machines with Kontur (Contour) weather radar in the nose and emergency exits in each rear window were designated "Mi-8TM".
- A very small number of Mi-8Ts were built as VIP transports for the Red Navy and Air Force, with the designation of "Mi-8TS".
[1.5] SECOND-GENERATION MI-8MT
* The Kazan plant built about 4,500 first-generation "Hips" in all, with about 1,700 exported, with about 3,700 built at Ulan-Ude, all for Soviet use. That quantity alone would make the "Hip" significant, but the machine was really only beginning its design life.
From the mid-1960s there was work on an enlarged and improved version of the Mi-8, which was assigned the provisional designation of "Mi-8M", the "M" effectively standing for "modernized". The project bogged down and was cancelled in the early 1970s, but it served as the basis for the "Mi-8MT", the starting point of a less ambitious second-generation Mi-8 series -- here informally referred to as "Mi-8 Series II" as compared to first generation "Mi-8 Series I" machines, though these designations were never actually used in service.
The major improvement in the Series II was the fit of more powerful TV3-117MT turboshafts -- developed for the heavier Mi-14 "Haze" and with 1,420 kW (1,900 SHP) each -- along with an uprated rotor transmission system to handle the greater power. The tail rotor was switched from the right side of the tailboom to the left, which improved its effectiveness. An Ivchenko Al-9V auxiliary power unit (APU) was added, being placed at the rear of the engine fairing and making the fairing noticeably enlarged to the rear, with an exhaust for the APU on the left side. An emergency exit was added in a cabin window on the right side of the fuselage. Although the Mi-8-II otherwise looked much like the first generation, there were many production changes "under the skin" to reduce weight and improve durability.
As with the original Mi-8T, the Mi-8MT could be equipped with armament. Originally the armament was the same as with the Mi-8TV, consisting of a 7.62 millimeter PKT machine gun in the nose -- the gun position, however, was moved upward -- and outriggers for carriage of rocket pods and anti-tank guided missiles. There was no distinct designation for an armed Mi-8MT.
Since production of Mi-8 Series I machines was well-established, there was some resistance in the bureaucracy to take on the burden of shifting production to a substantially updated version. However, the performance of the Series I under "hot and high" (hot weather, high ground altitude) conditions was marginal and there was considerable pressure to move to the more powerful second generation.
The Mi-8MT went into production at the Kazan plant in 1977. The new variant was displayed at the Paris air show in 1981, with NATO assigning it the codename "Hip-H". Export variants were given the general designation of "Mi-17". Mi-8 Series I models remained in production in parallel for a time, partly because production of TV3-117MT engines was limited, partly because it wasn't possible to replace all the specialized Mi-8-I subvariants on the manufacturing lines right away. Series I "Hips" were finally out of production by 1986.
* Combat experience during the Soviet war in Afghanistan through the 1980s demonstrated that much needed to be done to improve the "Hip's" survivability. Given that "hot & high" conditions were normal in the country the Series I machines were clearly inadequate; but the Series II machines also left something to be desired. Necessary improvements were rolled into production on an ongoing basis:
- The hatch in the clamshell cargo doors was enlarged to permit better handling of a machine gun, or for escape in an emergency.
- Afghanistan tends toward the dry and dusty, which meant that Mi-8s tended to throw up a storm of dust on takeoffs and landings. The dust tended to be hard on engines, so intake filters were developed, in the form of hemispherical caps mounted over the engine intakes. The filters promoted a vortex that tossed the dust out of the intake airstream. They were known by the designation "PZU", for "piyle-zashchitnoye ustroystvo (anti-dust device)", and were often retrofitted on older machines in service.
- Combat experience suggested that better armament was required. Two or four PKT machine guns, complementing the nose gun, were fitted to the outriggers, and some "Hips" were fitted with a 12.7 millimeter (0.50 caliber) NSV-12.7 Utyos (Cliff) machine gun or 30 millimeter Plamya (Flame) automatic grenade launcher on a flexible mount in the side door and rear hatch.
Unguided rocket pods were a common outrigger store, though the 57 millimeter rocket was less well-liked than the 80 millimeter rocket, carried in 20-round pods. Gun pods were popular as well, particularly the UPK-23-250 with a two-barreled GSh-23L cannon and 250 rounds of ammunition - "UPK" stood for "unifitseerovanniy pusheschniy konteyner (standardized gun pod)".
- Combat also demonstrated the need for countermeasures against heat-seeking man-portable anti-aircraft missiles like the US Stinger. Exhaust filters to mask the hot exhaust flow with cool air were fitted to machines built from 1984 -- they couldn't be retrofitted to older machines. Chaff-flare dispensers were initially scabbed onto the bottom of the tailboom, to be later mounted on the fuselage, and an infrared countermeasures (IRCM) "disco light" was mounted behind the rotor mast.
- Internal cockpit and seat armor was added, along with armor panels were provided that could be scabbed on to the nose externally, with the total armor load amounting to 180 kilograms (400 pounds).
Floatation gear was developed for the Mi-8TV series, with inflatable packs alongside the nose and on the mainwheels, giving the misleading appearance of spats; they seem to be a rare fit, usually associated with civil and SAR variants.
* There was, to no surprise, a wide range of subvariants of the Mi-8-II series. The "Mi-19" was a follow-on to the Mi-9 aerial battlefield command post, with a specialized version, the "Mi-19R", produced for the Soviet Strategic Rocket Force, it seems for mobile missile launch units.
There was a wide range of ECM variants with designations such as "Mi-8MTI", "Mi-8MTP", "Mi-8MTPB", "Mi-8MTPI", "Mi-8MTPSh", "Mi-8MTD", "Mi-8MTS", "Mi-8MTR1" & "Mi-8MTR2", "Mi-8MTU", "Mi-8MTSh1", "Mi-8MTSh2", "Mi-8MTSh3", "Mi-8MTYa", and "Mi-8MT-1S". Export models were designated "Mi-17P", "Mi-17PI", and "Mi-17PG". Many were one-of-a-kind fits; NATO understandably shrugged and designated them all "Hip-K" since the alphabet was running out of letters.
A passenger version of the Mi-8TV was sold for export as the "M-17P". It was configured much like an Mi-8P but had circular windows. There were a number of VIP conversions as well, with a confusing variety of designations; the "Mi-8MS" designation is used here for all of them. Other subvariants included:
- A number of medevac and flying ambulance variants, the most prominent being the "Mi-8MTB", Which featured armor and a surgical station. It saw use during the conflict in Afghanistan.
- The "Mi-8MTL", a fire-bomber, similar to the Mi-8TL, which was put into relatively widespread service.
Other conversions and modifications of the Mi-8-II included a dozen modified for weather research; a testbed for radar systems; and test or trials machines.
[1.6] MI-8 SERIES IN THE POST-SOVIET ERA
* In the later 1980s, the Mi-8-II series was fitted with improved TV3-117VM turboshafts -- they had the same power rating as earlier TV3-117MT but, partly thanks to an electro-hydraulic engine control system, could maintain power much better under "hot & high" conditions. Development had been driven by experience in Afghanistan, but work on the improved engine variant was protracted and it wasn't available until the Soviets were on the way out of the conflict.
The baseline model of the revised "Hip" series was the "Mi-8MTV", where "V" stood for "vysotniy (high altitude)"; it was sold for export as the "Mi-17V". Other fits to the variant were continuation of and improvement on fixes gradually added in response to combat in Afghanistan, produced as standard: additional armor, foam-filled fuel tanks to reduce explosion hazard, modification of some components and layout to improve survivability, more chaff-flare dispensers, exhausts modified to permit fit of exhaust filters, and the rear mount for a PKT machine gun. There were three main production variations:
- The "Mi-8MTV-1 / Mi-17-1V", notice the odd suffix for the export version, was a civil variant, lacking armor and other combat kit. It was sold with a Kontur (Contour) weather radar in a pod fitted into the lower forward panel of the nose glazing.
- The "Mi-8MTV-2 / Mi-17-1V" was a transport / gunship variant, with full combat kit and the Kontur nose radar -- the export variant had the same designation as that for the Mi-8MTV-1. It had improved avionics and, given the increase in power, external sling load of 5 tonnes (11,000 pounds), passenger load increased from 24 to 30, with a centerline row of seats. Along with the nose and tail guns, there were mounts for up to eight light machine guns in the side doors and windows.
- The "Mi-8MTV-3 / Mi-17V-3" was a slight upgrade of the Mi-8. Oddly it eliminated the nose gun and reduced the stores pylons from six to four, but it permitted a greater variety of external stores and had other small improvements.
One Mi-8MTV-1 was modified into the "Mi-8MTV-K" flying crane, with a distinctive crane operator's cab replacing the rear clamshell doors; this subvariant didn't go into production. There was also an ambulance version, the "Mi-8MTVM"; its production status is unclear.
* After the collapse of the Soviet Union, the Kazan and Ulan-Ude plants continued to build and develop the Mi-8 series, but they did it more or less independently -- becoming "bitter friends" and competitors. The Kazan plant became the "Kazan Helicopters" company, while Ulan-Ude became very simply the "Ulan-Ude Aviation Plant (UUAP)". While domestic orders were slow, there was still considerable interest from the export market.
Kazan Helicopters proved aggressive in trying to update the Mi-8 series, developing a "third generation" series and introducing the "Mi-8MTV-5" in 1996. It was clearly a new machine. Instead of tacking on a radar in a nose pod, the nose was reprofiled with an integral tilt-up nose radome, which was not only a cleaner implementation but allowed relatively easy fit of different radars. The new nose is referred to as a "Dolphin" nose, partly because of its resemblance to the seagoing mammal but also because of its resemblance to the French Aerospatiale / Eurocopter "Dauphin" helicopter.
A double-wide door was added since it was hard for troops to get out if a machine gun or grenade launcher was mounted in the door. In addition, in full development the Mi-8MTV-5 dispensed with the classic clamshell rear doors of the Mi-8, replacing them with a tilt-down hydraulically-operated rear door / loading ramp like that of the Mi-26 "Halo" heavylift helicopter. The ramp could be opened in flight for airdrops. Maximum passenger capacity was raised to 40. Ceramic armor was added, and avionics systems were upgraded across the board. Very much the same machine was also sold as the "Mi-17V-5" for exports. First deliveries were in 2000.
A version with Westernized avionics, integrated by the Canadian firm Kelowna Flightcraft, was offered for export as the "Mi-17MD", with the "Mi-17MDN" being a derived version with a night vision turret for night combat.
Along with military variants, Kazan Helicopters offers an "Mi-172" series for civil and VIP transport service, with the latest options, square windows and soundproofing, but the traditional rear clamshell door arrangement. The office of the Russian president obtained one with armor, small square windows, exhaust filters, and chaff-flare dispensers. India has obtained the Mi-172 with a specified equipment fit.
Kazan Helicopters has been working on a fourth-generation "Hip", the "Mi-173", following the Mi-17MD but featuring a stretched fuselage, improved avionics including a glass cockpit, new and more powerful VK-2500 engines with 1,800 kW (2,425 SHP) each, composite rotors, and an X-type tail rotor derived from the Mil Mi-28N "Havoc" gunship. Some export machines, informally designated "Mi-17V-6", have already been shipped to China with the VK-2500 engines.
Work is underway on a further refined "Mi-38". Details are unclear; a prototype with twin Pratt & Whitney Canada (PWC) PW127TS turboshafts has been flown, but production is expected to use Russian-built TV7-117V turboshafts. Images of the prototype show it to be externally generally similar to other late-model Mi-8/17 variants, with a dolphin nose and rear loading ramp. Difficulties over engine issues have the program on hold for the time being, though officials believe that development should be completed by 2014.
* UUAP went on to their own "third generation", beginning with the "Mi-8AMT", designated "Mi-171" for export. It retained the rounded nose of previous "Hips" but added the improved TV3-117VT engines, the new tail ramp, and improved avionics. A dolphin nose with a slightly sharper profile from the Mi-8MTV-5 is offered as a option, though the traditional undernose radar pod may be selected instead.
Ulan-Ude created an updated combat version, the "Mi-8AMTSh", featuring armament derived from the Mil Mi-24V helicopter gunship, including Shturm (AT-6) or Ataka (AT-9) anti-armor missiles and Igla-V (SA-18) air-to-air missiles. The Mi-8AMTSh retains six pylons. The Shturm is the favored weapon system, with a pack of four on each outer pylon for a total of eight. Iglas can be carried in twinpacks on each inner pylon for a total of four. The Mi-8AMTSh features a sighting system under the nose on the left and a radio guidance link pod on the right. Initial flight of the Mi-8AMTSh was in 1996. The variant is offered for export sales as the "Mi-171Sh". A night combat version, the "Mi-8MN", has also been introduced.
* Over 12,500 Mi-8 series helicopters were built up to 2005, making it one of the most important helicopters ever built, and sales are still going strong. Given the type's sturdiness, there is also a considerable trade in used machines. The fact that purely civil "Hips" are available allows them to be sold over the table to countries under international arms embargoes. Not surprisingly, sometimes the "civil" machines are promptly fitted with combat kit after delivery.
Upgrades are now being offered to countries that are users of older Mi-8s. Russian upgrades range from simple refurbishment and "zero-lifing" of airframes -- with new, sturdier composite rotors offered as a somewhat expensive option -- to avionics and weapons upgrades. Kazan Helicopters developed a night combat upgrade for the Mi-MT, with a night vision goggle (NVG) compatible cockpit, a GOES-321 night vision turret, and improved avionics. That particular update was developed in response to a Russian military requirement; updated machines were designated "Mi-8MTKO" or "Mi-17N" for export, and saw combat in Chechnya during the conflicts of the Soviet Succession.
Israel Aircraft Industries (IAI) has been pushing their own range of upgrades, with their "Peak 17" demonstrator featuring a full "glass cockpit", other modernized Israeli avionics, an Israeli-built self-defense suite, and compatibility with Israeli-built weapons such as the Rafael Spike antitank missile series. Elbit of Israel also offers comparable upgrades. The Russians loudly objected to the Israeli "Hip" upgrade efforts, claiming the Israelis had no right to tinker with Russian-built machines without Russian authorization, and IAI did come to an agreement with the Russians on the matter.
Even SAGEM of France and BAE Systems of the UK have offered "Hip" upgrade packages. However, so far users of older "Hips" have not been interested in expensive upgrades, focusing more on refurbishment and a modest avionics enhancement to provide such straightforward items as a GPS navigation satellite receiver. Ex-Warsaw Pact nations that have now joined NATO have also opted to obtain NATO-compatible communications and identification friend or foe (IFF) systems. There are also upgrades to provide additional external fuel carriage, either by adding another external tank high on each side of the fuselage, or by providing "wet" outrigger pylons to permit the carriage of up to six external tanks.
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