The Mil Mi-24 (Cyrillic Миль Ми-24, NATO reporting name "Hind") is a large helicopter gunship and low-capacity troop transport produced by Mil Moscow Helicopter Plant and operated from 1972 by the Soviet Air Force, its successors, and over thirty other nations.
In NATO circles the export versions, Mi-25 and Mi-35, are simply denoted with a letter suffix as "Hind D" and "Hind E" respectively. Soviet pilots called the aircraft летающий танк (letayushchiy tank, “flying tank”). More common unofficial nicknames were Крокодил (Krokodil, “Crocodile”), due to the helicopter's new camouflage scheme and Стакан (Stakan, “Glass”), because of the flat glass plates which surrounded the three place cockpit of the Hind A version.
During the early 1960s, it became apparent to Soviet designer Mikhail Leont'yevich Mil that the trend towards ever-increasing battlefield mobility would result in the creation of flying infantry fighting vehicles, which could be used to perform both fire support and infantry transport missions. The first expression of this concept was a mock-up unveiled in 1966 in the experimental shop of the Ministry of Aircraft's factory number 329 where Mil was head designer. The mock-up designated V-24 was based on another project, the V-22 utility helicopter, which itself never flew. The V-24 was similar in layout and configuration to the UH-1A Huey, with a central infantry compartment that could hold eight troops sitting back to back, and a set of small wings positioned to the top rear of the passenger cabin, capable of holding up to six missiles or rockets, with a twin-barreled GSh-23L cannon fixed to the landing skid.
Mil proposed the design to the heads of the Soviet armed forces, and while he had the support of a number of strategists in the armed forces, he was opposed by several more senior members of the armed forces who believed that conventional weapons were a better use of resources. Despite the opposition, Mil managed to persuade the defence minister's first deputy, Marshal Andrey A. Grechko, to convene an expert panel to look into the matter. While the panel's opinions were mixed, supporters of the project eventually held sway, and a request for design proposals for a battlefield support helicopter was issued.
Mil engineers prepared two basic designs: a 7-ton single-engine design and a 10.5-ton twin-engine design, both based on the 1,700 hp Izotov TV3-177A turboshaft. Later, three complete mock-ups were produced, along with five cockpit mock-ups to allow the pilot and weapon station operator positions to be fine-tuned.
The Kamov bureau suggested an army version of their Ka-25 Hormone ASW helicopter as a low-cost option. This was considered but later dropped in favor of the new Mil twin-engine design. A number of changes were made at the insistence of the military, including the replacement of the 23 mm cannon with a rapid-fire heavy machine gun mounted in a chin turret, and the use of the then-under development 9K114 Shturm (AT-6 Spiral) anti-tank missile.
A directive was issued on 6 May 1968 to proceed with development of the twin-engine design. Work proceeded under Mil until his death in 1970. Detailed design work began in August 1968 under the codename Yellow 24. A full scale mock-up of the design was reviewed and approved in February 1969. Flight tests with a prototype began on 15 September 1969 with a tethered hover, and four days later the first free flight was conducted. A second prototype was built, followed by a test batch of ten helicopters.
Acceptance testing for the design began in June 1970, continuing for 18 months. Changes made in the design addressed structural strength and fatigue problems, and reduced vibration levels. Also, a 12-degree anhedral was introduced to the wings to address the aircraft's tendency to Dutch roll at speeds in excess of 200 km/h, and the Falanga missile pylons were moved from the fuselage to the wingtips. This gave the helicopter its characteristic wings. The tail rotor was moved from the right to the left side of the tail, and the rotation direction reversed. The tail rotor now rotated up on the side towards the front of the aircraft, into the downwash of the rotor, which increased the efficiency of the tail rotor. A number of other design changes were made until the production version Mi-24A (izdeliye 245) entered production in 1970, obtaining its IOC in 1971. It was officially accepted into the state arsenal in 1972.
The core of the aircraft was derived from the Mil Mi-8 (NATO reporting name "Hip"), two top-mounted turboshaft engines driving a mid-mounted 17.3 m five-blade main rotor and a three-blade tail rotor. The engine configuration gave the aircraft its distinctive double air intake. Original versions have an angular greenhouse-style cockpit; Model D and later have a characteristic tandem cockpit with a "double bubble" canopy. Other airframe components came from the Mi-14 "Haze". Two mid-mounted stub wings provide weapon hardpoints, each offering three stations, in addition to providing lift. The load-out mix is mission dependent; Hinds can be tasked with close air support, anti-tank operations, or aerial combat. The body is heavily armored and the titanium rotor blades can resist impacts from .50 caliber (12.7 mm) rounds. The cockpit is overpressurized to protect the crew in NBC conditions.
Considerable attention was given to making the Mi-24 fast. The airframe was streamlined, and fitted with retractable tricycle undercarriage landing gear to reduce drag. The wings provide considerable lift at high speed, up to a quarter of total lift. The main rotor was tilted 2.5° to the right from the fuselage to counteract dissymmetry of lift at high speed and provide a more stable firing platform. The landing gear was also tilted to the left so the rotor would still be level when the aircraft was on the ground, making the rest of the airframe tilt to the left. The tail was also asymmetrical to give a side force at speed, thus unloading the tail rotor.
As a combination gunship and troop transport, the Mi-24 has no direct NATO counterpart. While some have compared the UH-1 ("Huey") as NATO's direct counterpart to the Mi-24, this is inaccurate. While UH-1s were used in Vietnam to ferry troops, and were used as gunships, they were not able to do both at the same time. Converting a UH-1 into a gunship meant stripping the entire passenger area to accommodate extra fuel and ammunition, making it useless for troop transport. The Mi-24 was designed to do both, and this was greatly exploited by airborne units of the Soviet Army during the 1980-1989 Soviet invasion of Afghanistan. The closest Western equivalent was the Sikorsky S-67 Blackhawk, which utilized many of the same design principles and was also built as a high-speed, high-agility attack helicopter with limited troop transport capability; it, like the Hind, was also designed using many components from an already existing product, the Sikorsky S-61, itself a close approximation to the Mi-8/Mi-14. The S-67, however, was never adopted for service.
In March 1987 the Armed Forces of the North, which were backed by the USA and France, managed to seize a Libyan airforce base at Ouadi-Doum in Northern Chad. Among the aircraft captured during this raid were three Mi-25s. These were turned over to France, which in turn sent one to the United Kingdom and one to the USA.
The situation in Afghanistan grew worse and on 25 December 1979 Soviet troops were committed to the war, an action that would prove a major blunder. The Red Army found itself involved in a guerrilla war in a country where the rugged terrain favored the locals, who were enthusiastic, competent, and thoroughly determined fighters. The Hind seemed like an excellent weapon to help deal with the Mujahideen. Soviet field commanders requested all the Hinds they could get.
The Hind's favored munition was the 80mm (3.15 in) S-8 rocket, the 57mm (2.24 in) S-5 having proven too light to be effective. The 23 mm (0.98 in) gun pod was also popular. Extra rounds of rocket ammunition were often carried internally so that the crew could land and self-reload in the field. The Hind could carry ten 100-kilogram (220-pound) iron bombs for attacks on strongpoints, while harder targets could be dealt with a load of four 250-kilogram (550-pound) or two 500-kilogram (1,100-pound) iron bombs. Some Hind crews became expert "snipers" dropping or tossing bombs precisely on targets. Fuel-air explosive bombs were also used in a few instances, though crews initially underestimated the sheer blast force of such weapons and were caught by shock waves that rattled their teeth.
Combat experience quickly demonstrated the disadvantages of having Hinds carrying troops. Gunship crews found the soldiers a concern and a distraction while being shot at, and preferred to fly lightly loaded anyway, especially given their operations from high ground altitudes in Afghanistan. Hind troop compartment armor was often removed to reduce weight. Troops would be carried in Mi-8 helicopters while the Hinds provided fire support.
It did prove useful to carry a technician in the Hind's crew compartment, handling a light machine gun in a window port. This gave the Hind some ability to "watch its back" while leaving a target area. In some cases a light machine gun was fitted on both sides to allow the technician to move from one side to the other without having to take the machine gun with him. Trying to shift a machine gun from one side of a helicopter to another while it maneuvered under fire was not merely clumsy and inconvenient, it was an invitation to deadly accidents.
This weapon configuration still left the gunship blind to the direct rear, and Mil experimented with fitting a machine gun in the back of the fuselage, accessible to the gunner through a narrow crawlway. The experiment was highly unsuccessful, as the space was cramped, full of engine exhaust fumes and was otherwise unbearable. During a demonstration an overweight Soviet Air Force general got stuck in the crawlway. Operational Hinds were retrofitted with rear-view mirrors to help the pilot spot threats and take evasive action.
The Hinds not only protected helicopter troop assaults and supported ground actions; they also protected convoys, using rockets with flechette warheads to drive off Mujahideen ambushes, performed strikes on predesignated targets, and engaged in "hunter-killer" sweeps. The hunter-killer Hinds operated in pairs at minimum, more often groups of four or eight, to provide mutual fire support. The Mujahideen learned to move mostly at night to avoid the gunships, and in response the Soviets trained their Hind crews in night-fighting, dropping parachute flares to illuminate potential targets for attack. The Mujahideen quickly caught on and scattered as quickly as possible when Soviet target designation flares were lit nearby.
Then CIA began to supply the rebels with Stinger shoulder-launched, heat-seeking SAMs, and the situation got considerably worse. The Mi-24's exhaust that the heat-seeking missiles sought out was located directly under the main rotor, which caused the aircraft to disintegrate when hit. This was later remedied by countermeasure flares and a missile warning systems installed in all Soviet Mi-4, Mi-8, and Mi-24 helicopters, giving pilots a chance to evade the missile or crash-land. Heat dissipaters were also fitted to exhausts to decrease the Hind's heat signature. These alleviated the Stinger threat without eliminating it.
Hinds were also used to shield jet transports flying in and out of Kabul from Stingers. The gunships carried flares to blind the missiles, and if worse came to worst, were under orders to try to take the hit from the missile themselves. The crews called themselves "Mandatory Matrosovs", after a hero of the Second World War who threw himself across a German machine gun to let his comrades break through.
In such a kill-or-be-killed environment, Hind crews acquired a certain edge. Early in the war, head of Mil Marat Timoschenko visited Afghanistan to see what the troops thought of his helicopters, and gunship crews put on spectacular displays for him. They even demonstrated maneuvers, such as barrel rolls, which design engineers considered impossible. An astounded Dr. Timoschenko commented, "I thought I knew what my helicopters could do, now I'm not so sure!"
Hinds passed on to pro-Soviet Afghan forces during the war remained in dwindling service in the grinding civil war that followed the Soviet withdrawal. Some were flown by defectors to Pakistan, and a few of these machines apparently found their way into the hands of the US Army.
Afghan Hinds in the hands of the ascendant Taliban gradually became inoperable, but a few flown by the Northern Alliance, which had Russian assistance and access to spares, remained operational up to the US intervention in Afghanistan in the fall of 2001. In 2008, the Afghan National Air Corps took delivery of six refurbished Mi-35 Hind helicopters, purchased from the Czech Republic with US money. The Afghan pilots were trained by India and were due to begin live firing exercises in May 2008 in order to escort Mi-17 transport helicopters on operations in restive parts of the country.
This war also saw the only confirmed air-to-air helicopter battles in history with the Iraqi Mi-25s flying against Iranian AH-1J SeaCobras (supplied by the United States before the revolution) on several separate occasions. Not long after Iraq's initial invasion of Iran on 22 September 1980, two Iranian SeaCobras crept up on two Hinds and hit them with TOW wire-guided antitank missiles. One Mi-25 went down immediately, the other was badly damaged and crashed before reaching base. The Iranians pulled off a repeat performance on 24 April 1981, destroying two Mi-25s without incurring losses to themselves.
The Iraqis hit back, claiming the destruction of a SeaCobra on 14 September 1983; three SeaCobras on 5 February 1984; and three more on 25 February 1984. After a lull in helicopter losses, each side lost a gunship on 13 February 1986. A few days later, on 16 February, a Mi-25 shot down a SeaCobra, and a SeaCobra claimed a Hind on 18 February. The last engagement between the two types was on 22 May 1986, when Hinds shot down a SeaCobra.
The final claim tally was 10 SeaCobras destroyed and 6 Mi-25s destroyed. The relatively small numbers and the inevitable disputes over actual kill numbers makes it unclear if one gunship had a real technical superiority over the other. It appears that the outcome of the fights was dependent more on the tactical situation and pilot skill than the inherent merits of each machine. Iraqi Hinds also claimed a total of 43 kills against other Iranian helicopters, such as Agusta-Bell Hueys. However, these findings are disputed, and it has been suggested by unclassified sources that "Iranian AH-1 pilots achieved a 10:1 kill ratio over the Iraqi [MI-8 Hip and MI-24 Hind] pilots during these engagements (1:5)".
In general the Iraqi pilots liked the Mi-25, in particular for its high speed, long range, high versatility and large weapon load, but disliked the relatively ineffectual weapons and lack of agility.
Two Mi-25s were shot down by Stingers fired by the Contras. A third Hind was damaged while pursuing Contras near the Honduran border, when it was pounced on by Honduran F-86 Sabres and A-37 Dragonflies. A fourth was flown by a defecting Sandinista pilot to Honduras in December 1988.
The Indian Peace Keeping Force (1987-1990) in Sri Lanka used Mi-24s when an Indian Air Force detachment was deployed there in support of the Indian and Sri Lankan armed forces in their fight against various Tamil militant groups such as the LTTE. It is believed that Indian losses were considerably reduced by the heavy fire support provided by their Mi-24 gunships. The Indians lost no Mi-24s in the operation, as the Tigers had no weapons capable of dealing with the Crocodile at the time, although several sustained heavy damage from machine gun fire.
Since 14 November 1995, the Mi-24 has been used by the Sri Lanka Air Force in the continuing war against the LTTE and has proved highly effective providing close air support for ground forces. The Sri Lanka Air Force currently operates a mix of Mi-24/-35P and Mi-24V/-35 versions. They have recently been upgraded with modern Israeli FLIR and electronic warfare systems. Five were upgraded to intercept aircraft by adding radar, fully functional helmet mounted target tracking systems, and AAMs. At least five Hinds have been lost to LTTE MANPADs, and another two lost in attacks on airbases, with one heavily damaged but later returned to service.
The Mi-24 was also heavily employed by Iraqis during their invasion of Kuwait, although most were withdrawn by Saddam Hussein when it became apparent they would be needed to help retain his grip on power in the aftermath of the war.
A few Hinds were later sent over the border into Iran, along with many other Iraqi military aircraft, in the hope of sparing them from destruction by allied air strikes. As with the previous Iraqi aircraft however, the Iranians kept them and used them in their own service.
On the night of 1 March 1998, during the fighting against KLA forces in Kosovo, a Serbian Special Operations Unit landed in the village of Prekaz. One of its Mi-24Ds was hit by small arms fire and made an emergency landing, but the KLA fighters were allegedly pushed back by JSO personnel. During the summer of 1998, Mi-24Ds took part in several combat missions. On June 27, JSO forces used four helicopters to come to the aid of approximately 100 police officers and Serbian civilians fleeing a NATO blockade in the village of Kijevo. The Mi-24Ds and Mi-17s transported ammunition and evacuated wounded.
The Macedonian armed forces acquired second hand Ukranian Mi-24Vs. They were used frequently against Albanian armed resistance during the 2001 conflict in Macedonia. The main areas of action were in Tetovo, Radusha and Aracinovo. The aircraft saw heavy use and proved to be highly in-effective against guerilla forces in a guerilla war, the helicopters spend most of their time flying low and fast over the villages and towns under Albanian control firing flares to scare and panic people. Till this day there has not been a single proven kill of Guerilla forces by an Mi-24.
Afghanistan: 115 have been delivered to the Afghan Air Force since 1979, and four remain operational. Algeria Angola Armenia: 12 in service with the Armenian Air Force. : 44 delivered in 1979-1986. Still in service. maroc: 12 Mi-35Ps delivered in 2001-2005. Croatia: Grounded and retired. Cuba Czech Republic: East German Air Force : 51 taken over from East Germany's Army, sold to Hungary, Poland and two to the US Army. Equatorial Guinea Eritrea Ethiopia Georgia: 32 MI-24,5 MI-35 Georgian Air Force. Guinea: 49, 20 from the German Army (taken over from East German Army) Indonesia: Two Mi-35Ps operated by the Army Corps/TNI-AD (bought in 2004), five Mi-35Ps ordered in 2006, and an additional three Mi-35s in 2007. So far eight are in service. Iraq Kazakhstan Kyrgyzstan Libya Republic of Macedonia Mongolia Mozambique Namibia: Namibian Air Force Nicaragua Nigeria North Korea Pakistan: One in service. Peru Poland
Since 1978 around 2,000 Mi-24s have been manufactured, 600 for export.