The experience of local conflicts has shown that a helicopter armed with anti-tank guided missiles is one of the most effective means of fighting tanks. For one shot down anti-tank helicopter, on average, there are 15-20 burned and destroyed tanks. But the conceptual approach to the creation of combat helicopters in our country and in the West was diametrically opposite.
In the armies of the NATO countries, relatively light two-seater helicopters armed with 4-6 ATGMs, a pair of NAR blocks and small arms and cannon armament of 7.62-20mm caliber were developed to combat the Soviet armada of many thousands. Often, such rotary-wing machines were created on the basis of general-purpose helicopters, which did not have any significant reservation. It was believed that due to the ease of control and good maneuverability, light anti-tank helicopters would avoid large losses. Their main purpose was to repel tank attacks on the battlefield, taking into account the ATGM launch range of 4-5 km, it was possible to defeat armored vehicles without crossing the front line. When striking attacking tank wedges, when there is no solid line of fire contact, helicopters should actively use the terrain folds, acting from a jump. In this case, the military air defense systems have very little time to react.
In the USSR, a different approach prevailed: our top military leadership expressed a desire to receive a well-protected combat helicopter with powerful weapons, capable, moreover, of delivering troops. It is clear that such a machine, a kind of "flying infantry fighting vehicle", could not be light and cheap. The main task of such a helicopter was not even to fight tanks, but to deliver massive strikes against the foci of enemy defense with unguided weapons. That is, the flying armored MLRS was supposed to clear the way for its advancing tanks with volleys of numerous NARs. The surviving firing points and manpower of the enemy were to be destroyed by the fire of onboard cannons and machine guns. At the same time, the helicopter could also land troops in the near rear of the enemy, completing the encirclement and defeat of the enemy's defense.
This is how the Soviet top military leaders saw the concept of using a promising combat helicopter. The order for its creation was issued in 1968. During the design of the helicopter, which later received the designation Mi-24, technical solutions, components and assemblies already used on the Mi-8 and Mi-14 helicopters were widely used. It was possible to achieve unification in terms of engines, hub and rotor blades, tail rotor, swashplate, main gearbox and transmission. Thanks to this, the design and construction of the prototype was carried out at a high pace, and already in September 1969 the first copy of the helicopter entered testing.
One of the requirements of the military was the high flight speed of the Mi-24, since it was also planned to use it to counter enemy combat helicopters and conduct defensive air combat at low altitudes with enemy fighters. To achieve a flight speed of more than 300 km / h, not only engines with a high power density were required, but also perfect aerodynamics. The straight wing, on which the weapons were suspended, provided up to 25% of the total lift in steady flight. This effect is especially pronounced when performing vertical maneuvers, such as "slide" or "combat turn". Thanks to the wings, the Mi-24 gains altitude much faster, while the overload can reach 4 g.
However, the cockpit of the first serial modification of the Mi-24A was far from ideal. The flight crew called it a "veranda" for its characteristic shape. In the common cockpit, in front, there was a navigator-operator's workplace, behind him, with some displacement to the left, sat the pilot. This arrangement hampered the actions of the crew and limited the view. In addition, when the bulletproof glass was penetrated, the navigator and pilot could be injured from one shell, which negatively affected the combat survivability as a whole. In case the pilot was injured, the navigator had simplified equipment necessary to control the flight parameters and helicopter controls. In addition, the cockpit was quite cramped and cluttered with various equipment and sights, a machine gun mount took up a lot of space. In this regard, the cab was slightly lengthened on production vehicles.
The cockpit was protected by transparent frontal armor, side armor plates included in the fuselage power scheme. The navigator and pilot had armored seats. During combat missions, the crew had to use body armor and titanium helmets.
In the middle part of the helicopter there is a cargo-passenger cabin for 8 paratroopers. Opening portholes have pivot mountings that allow paratroopers to fire from personal small arms automatic weapons. Both cabins are sealed, the filtration and air conditioning system creates a slight overpressure in them to prevent the ingress of contaminated air when flying over contaminated terrain.
The Mi-24A was powered by two TVZ-117 engines. This new twin-shaft engine has already been tested on the Mi-14 amphibious helicopter. In the early 70s, he was one of the best in the world and was not inferior in terms of its performance to foreign models. TVZ-117 produced a take-off power of 2200 hp, nominal - 1700 hp, specific fuel consumption - 0.23-0.26 kg / hp hour. If one of the engines stopped, the other automatically switched to takeoff mode, which made it possible to return to its airfield. Five soft-sealed fuel tanks contained 2125 liters of kerosene. To increase the flight range inside the cargo compartment, it was planned to install two additional tanks with a total capacity of 1630 liters.
The Mi-24A was submitted for state testing in June 1970. Sixteen helicopters took part in the tests at once, which was unprecedented. During test flights, a helicopter with a maximum take-off weight of 11,000 kg with external weapon suspensions accelerated to 320 km / h. The carrying capacity of the transport-attack helicopter was 2,400 kg, including 8 paratroopers.
The tests of the helicopter took place quite quickly and in the second half of 1971, even before their full completion, the first Mi-24A began to enter combat units. Since the designers of the Mil Design Bureau were significantly ahead of the developers of promising weapons, the Mi-24A used weapons that had already been tested on the Mi-4AV and Mi-8TV. Serial Mi-24A were equipped with ATGM "Falanga-M" with four ATGM 9M17M and a mobile rifle mount with a large-caliber machine gun A-12, 7. On six external nodes could be placed: four blocks NAR UB-32A-24, or eight 100-kg OFAB-100 bombs, or four OFAB-250 or RBK-250 bombs, or two FAB-500 bombs, or two single RBK-500 cluster bombs, or two ODAB-500 volumetric detonating bombs, or two ZB-500 incendiary tanks, or two container of small-sized submunitions KMGU-2, or two containers UPK-23-250 with 23-mm rapid-fire guns GSH-23L. As in other Soviet combat helicopters, the navigator-operator was engaged in aiming the ATGM at the target, he also fired from a large-caliber machine gun with the help of a simple collimator sight. The launch of unguided rockets, as a rule, was carried out by the pilot.
The pilots who transferred to the Mi-24A from the Mi-1 and Mi-4 noted the good flight performance of the combat helicopter. In addition to high speed, they distinguished maneuverability and controllability good for a car of this dimension and weight. It was possible to perform combat turns with a roll exceeding 60 °, and climb with a pitch angle of up to 50 °. At the same time, the new helicopter had a number of drawbacks and was still damp. A lot of criticism was caused by the low resource of the engines, which did not exceed 50 hours in the first years of operation. At first, helicopter pilots who had previously flown other aircraft found it difficult to get used to the retractable landing gear. They often forgot to retract the landing gear after takeoff and, even worse, release it upon landing. This sometimes served as the reason for very serious flight accidents.
During the control and training launches of the ATGM, it suddenly became clear that the accuracy of the use of this weapon is worse than on the Mi-4AV and Mi-8TV. Only every third missile hit the target. This was largely due to the unsuccessful location of the sight and guidance equipment "Raduga-F" in the cockpit and the shading of the antenna of the command radio control line. In addition, when launching guided missiles, until they hit the target, it was required to strictly hold the helicopter along the course and altitude. In this regard, the flight crew frankly did not favor ATGMs and preferred to use unguided weapons - mainly 57-mm NAR S-5, of which the Mi-24A could have 128 shells.
In total, about 250 Mi-24A were built at the Arsenyev aircraft plant within 5 years. In addition to Soviet helicopter regiments, "twenty-fours" were supplied to the allies. The baptism of fire of the Mi-24A took place in 1978 during the Ethiopian-Somali war. Mi-24A with Cuban crews inflicted serious damage on Somali troops. Combat helicopters were especially effective against artillery positions and armored vehicles, with the main use of NAR. A special piquancy of the situation was given by the fact that both sides of the conflict were equipped with Soviet equipment and weapons, and the Mi-24A burned Soviet-made T-54 tanks. As a result, the Somali troops invading Ethiopia suffered a crushing defeat, and this was not a small merit of the combat helicopters. Due to the weakness of the Somali air defense and the low preparedness of the Mi-24A crews, the combatants involved in that conflict did not suffer combat losses. Operation of the Mi-24A abroad continued until the early 90s.
During the establishment of mass production, the designers continued to improve the armament of the helicopter. On the experimental modification of the Mi-24B, a mobile machine gun installation USPU-24 was installed with a high-speed (4000-4500 rounds per minute) four-barreled machine gun YAKB-12, 7 with a rotating block of barrels. The cartridges and ballistics of the YakB-12, 7 were similar to the A-12, 7 machine gun. In addition, a "double-bullet" cartridge was adopted for the new four-barreled machine gun. The new cartridge increased the effectiveness of the machine gun by about one and a half times when operating on manpower. Sighting range - up to 1500 m.
The installation, remotely controlled by the operator, allows firing at an angle of 60 ° in the horizontal plane, 20 ° up and 40 ° down. The machine gun mount was controlled using the KPS-53AV sighting station. The system of mobile small arms included an analog computer, coupled with sensors of onboard parameters, thanks to this, the accuracy of shooting increased significantly, since the amendments were introduced automatically. In addition, a modernized Falanga-P anti-tank missile system with a semi-automatic guidance system was installed on the Mi-24B. This made it possible to increase the probability of missiles hitting the target noticeably 3 times. Thanks to the gyro-stabilized guidance device, the helicopter, after launching the rocket, could maneuver within 60 ° along the course, which significantly increased its combat effectiveness. Several experienced Mi-24Bs were tested in 1972. According to their results, it became clear that for a comprehensive increase in combat effectiveness, the helicopter needs a complete redesign of the cockpit.
The developments on the Mi-24B were implemented on the serial Mi-24D. The production of a new modification of the "twenty-four" began in 1973. These helicopters were supplied for export under the designation Mi-25.
The most notable difference between the Mi-24D and the Mi-24A is the new cockpit. All crew members of the Mi-24D had isolated workplaces. Starting with this model, the helicopter acquired its familiar appearance, for which it was nicknamed "crocodile". The cockpit became "tandem", the pilot and navigator-operator were placed in different compartments, separated by an armored partition. Also, thanks to the double curvature of the frontal bulletproof glasses, their bullet resistance increased, which significantly increased the chances of survival when performing an attack. Thanks to the improved aerodynamics, the flight data of the helicopter increased slightly, and the maneuverability became higher.
Due to the unavailability of the promising ATGM "Shturm" on the Mi-24D, the ATGM "Falanga-P" with a semi-automatic guidance system was installed. In this regard, despite slightly improved flight data and increased visibility from the cockpit, the anti-tank capabilities of the helicopter have not changed compared to the experienced Mi-24B. Anti-tank radio command ATGM "Phalanx" were in service in our country from 1960 to 1993. They are still used in a number of countries.
The most massive modification was the Mi-24V. On this machine, it was possible to introduce a new 9K113 "Shturm-V" ATGM with the "Raduga-Sh" guidance system. The eyepiece of the ATGM guidance system was located on the starboard side of the weapons operator's cabin. On the left side there is a radio-transparent radome for the ATGM guidance antenna.
The two-stage missile 9M114 "Shturm" has an aimed launch range of up to 5000 m, and develops a speed of up to 400 m / s in flight. Thanks to the supersonic flight speed, the time required to hit the target after the launch of the ATGM has been significantly reduced. When firing at the maximum range, the missile flight time is 14 s.
With a launch mass of a rocket of about 32 kg, it is equipped with a warhead weighing just over 5 kg. Armor penetration is 500 mm of homogeneous armor at an encounter angle of 90 °. At the test site, the probability of hitting the target 0.92 0, 8. Combat helicopter Mi-24V with the Shturm-V complex was adopted in 1976.
By the beginning of the serial production of the Mi-24V, the combat helicopter regiments already had approximately 400 Mi-24A and Mi-24D. For 10 years of serial production, about 1000 Mi-24V was handed over to the customer.
In addition to 57-mm unguided missiles, the armament includes new powerful 80-mm NAR S-8 in 20 B-8V20A charging blocks. The S-8KO cumulative fragmentation unguided missiles with normal penetration of 400 mm of homogeneous armor were able to effectively defeat any tanks in the 70s.
Compared to the "twenty-four" of earlier modifications, the range of weapons of the Mi-24V has expanded significantly. In addition to four ATGM "Shturm-V", 80-mm NAR S-8, for the first time a 122-mm NAR S-13 could be used on a combat helicopter. Although the S-13 was created primarily for the destruction of capital defensive structures and reinforced concrete aviation shelters, sufficiently large rockets weighing 57-75 kg, depending on the modification, can be successfully used against armored vehicles. NAR S-13 are loaded into five-charge blocks B-13.
During the tests, it turned out that fragments of a high-explosive fragmentation warhead weighing 33 kg at a distance of up to 5-10 m are capable of penetrating the armor of armored personnel carriers and infantry fighting vehicles. Moreover, after breaking through the armor, the fragments have a good incendiary effect. During control tests against armored vehicles, as a result of a direct hit of the S-13OF in a heavy tank IS-3M, a guide and two road wheels, as well as 1.5 m of a caterpillar, were torn out. The bulletproof blinds 50 mm thick on the engine compartment bent 25-30 mm. The tank gun was pierced in several places. If it was a real enemy tank, it would need to be evacuated to the rear for long-term repairs. When the decommissioned BMP-1 entered the stern part, the landing squad was completely destroyed. The explosion tore out three rollers and tore off the tower. In a salvo when launched from a distance of 1500-1600 m, the spread of missiles at the target did not exceed 8 m. Thus, the NAR S-13 could be effectively used to attack a column of enemy armored vehicles, being outside the effective range of anti-aircraft large-caliber machine guns.
The NAR is launched by the pilot using the ASP-17V collimator sight, which can also be used for firing a machine gun when fixing it along the helicopter axis and bombing. The Mi-24V can carry four aerial bombs with a caliber of up to 250 kg. The helicopter can take two FAB-500 bombs or ZB-500 incendiary tanks or KMGU-2 containers. It is possible to simultaneously suspend bombs and NAR blocks. On the inner pylons, when operating against enemy manpower, two UPK-23-250 containers with 23-mm cannons can be placed, as well as universal helicopter nacelles with a 30-mm grenade launcher, or with two 7, 62-mm machine guns GSHG-7, 62 and one 12, 7-mm machine gun YakB-12, 7. In the mid-80s, the number of ATGMs on a helicopter was doubled.
The Mi-24V received onboard equipment that was quite perfect by the standards of the 70s. Including three VHF and one HF radio stations. For the first time on a combat helicopter, designed to combat tanks and direct fire support of ground units, there was a secret communication equipment, with the help of which communication with ground aircraft controllers was provided.
To counteract ground-based air defense and protect against missiles with thermal homing heads, there was an indicator of radar exposure of the S-3M "Sirena" or L-006 "Bereza" radar, an optical-electronic jamming station SOEP-V1A "Lipa" and a device for shooting heat traps. In the “Lipa” thermal noise generator with the help of a heating element of a powerful xenon lamp and a system of rotating lenses around the helicopter, a pulsed stream of continuously moving infrared rays was formed.
In the case of the simultaneous use of "Lipa" with heat traps and the seeker, in most cases it was disoriented, and the rocket "yawned" between the traps and the helicopter. The experience of combat operations has demonstrated the high effectiveness of this method of protection against MANPADS. The disadvantage of the jamming station installed on the Mi-24V is the presence of a "dead zone" at the bottom and the lack of protection from "Stingers" in this direction. The total efficiency of the Lipa optical-electronic jamming station with the simultaneous use of heat traps and means of reducing IR signature in Afghanistan was 70-85%.
In general, the Mi-24V helicopter managed to achieve an optimal balance of combat and flight characteristics with an acceptable level of technical reliability and performance. Designers and production workers have made a lot of effort to eliminate design flaws and numerous "children's sores". In the second half of the 70s, the flight and technical personnel mastered the "twenty-four" well, and they represented a formidable force that could have a significant impact on the course of hostilities. In total, in the first half of the 1980s, the Soviet Army had 15 separate combat helicopter regiments. As a rule, each regiment consisted of three squadrons: two 20 Mi-24s and one 20 Mi-8s. In addition, Mi-24s were part of separate helicopter combat control regiments.
