The experience of local conflicts has demonstrated that a helicopter armed with anti-tank guided missiles is one of the most effective means of combating tanks. For one shot-down anti-tank helicopter, an average of 15-20 burned and wrecked tanks. But the conceptual approach to the creation of combat helicopters was diametrically opposite in our country and in the West.
In the armies of NATO countries, relatively light two-seat helicopters armed with an 4-6 ATGM, a pair of NAR units and 7,62-20-caliber artillery guns were developed to combat the Soviet many thousands of tank armadas. Often these helicopters were created on the basis of general-purpose helicopters, which did not have any significant booking. It was believed that due to the ease of operation 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 launch range of the 4-5 ATGM, there was the possibility of destroying armored vehicles without crossing the front line. When attacking attacking tank wedges, when a solid line of fire contact does not exist, helicopters must actively use the folds of the terrain, acting from the jump. In this case, the air defense troops have very little time for reaction.
In the USSR, a different approach prevailed: our top military leaders expressed a desire to get a well-protected combat helicopter with powerful weapons, which is also capable of delivering troops. It is clear that such a machine, a kind of "flying BMP", could not be easy and cheap. The main task of such a helicopter was not even fighting against tanks, but delivering massive blows to the centers of enemy defenses with unmanaged means of destruction. That is, the flying armored MLRS was supposed to fire its numerous advancing tanks with volleys of numerous NARs. The surviving firing points and the enemy's manpower 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 rear of the enemy, completing the encirclement and rout of the enemy’s defenses.
That 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 year. 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 of the engines, hub and main rotor blades, tail rotor, skew machine, main gearbox and transmission. Due to this, the design and construction of the prototype were carried out at a high rate, and in September 1969, the first instance of the helicopter entered testing.
One of the demands of the military was the high speed of the Mi-24, since it was also planned to be used to counter enemy combat helicopters and to conduct defensive air combat at low altitudes with enemy fighters. To achieve a flight speed of more than 300 km / h, not only high power engines, but also perfect aerodynamics were required. The straight wing, on which the armament suspension was carried out, yielded in steady-state flight up to 25% of the total lifting force. Especially this effect affects when performing vertical maneuvers, such as a "slide" or "combat reversal." Thanks to the wings of the Mi-24 it gains height much faster, and the overload can reach 4 g.
However, the helicopter cabin of the first production version of the Mi-24А was far from ideal. The flight technical structure for its characteristic form called it a "veranda". In the common cockpit in the front was the workplace of the navigator operator, behind him with a slight shift to the left sat the pilot. Such a layout hamper the actions of the crew and limited the review. In addition, when the armored glass was broken through, the navigator and the pilot could be injured from one projectile, which adversely affected the combat survivability as a whole. In the event of a pilot being injured, the navigator had simplified equipment necessary to control the flight parameters and controls of the helicopter. In addition, the cabin was quite cramped and cluttered with various equipment and sights, a lot of space occupied by the machine gun installation. In this regard, on serial machines the cabin was slightly extended.
The cockpit was protected by frontal transparent armor, side armor plates included in the power circuit of the fuselage. The navigator and pilot had armored seats. During the execution of combat missions, the crew had to use body armor and titanium helmets.
In the middle of the helicopter is a cargo cabin on the 8 paratroopers. Opening portholes have pivot installations that allow paratroopers to fire from a personal automatic rifle weapons. Both cabins are airtight; the filtration and air-conditioning system creates a slight overpressure in them to prevent the ingress of contaminated air when flying over contaminated terrain.
On the Mi-24, two TVZ-117 engines were installed. This new twin-shaft engine was already tested on the amphibious helicopter Mi-14. At the beginning of the 70-s, he was one of the best in the world and was not inferior in its performance to foreign models. TVZ-117 gave off take-off power 2200 hp, nominal - 1700 hp, specific fuel consumption - 0,23-0,26 kg / hp.hour. In the case of stopping one of the engines, the other automatically switched to take-off mode, which made it possible to return to its aerodrome. There were 2125 and kerosene in five soft, protected fuel tanks. To increase the flight distance inside the cargo compartment, it was planned to install two additional tanks with a total capacity of 1630 l.
The Mi-24A was handed over to state trials in June 1970. In the tests participated immediately 16 helicopters, which was unprecedented. During the test flights, the helicopter with a maximum take-off weight of 11000 kg with external weapon suspension was accelerated to 320 km / h. The payload of the transport and attack helicopter was 2400 kg, including 8 paratroopers.
Tests of the helicopter passed fairly quickly and in the second half of the 1971 of the year, even before their full completion, the first Mi-24А began to arrive in combat units. Since the designers of the Mil Design Bureau significantly outstripped the developers of advanced weapons, the Mi-24А used weapons that had already been tested on the Mi-4AB and Mi-8TV. Serial Mi-24Аs were equipped with the Phalanga-M ATGM with four ATGM 9М17М and a mobile rifle installation with a large-caliber machine gun A-12,7. On the six outer nodes could be placed: four blocks NAR UB-32-24, or eight 100-kg bombs OFAB-100, or four OFAB-250 or RBC-250, or two bombs FAB-500, or two one-time bomb cassettes RBC -500, or two volume-detonating ODAB-500, two or incendiary tank ST-500, container or two small submunitions KMGU-2, or two containers CPC-23-250 23-mm with quick-cannon GSH-23L. Like other Soviet helicopter gunships, the navigator-operator was guiding the ATGM to 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 a pilot.
The pilots who transferred to the Mi-24 with the Mi-1 and the Mi-4, noted the good flight data of the combat helicopter. In addition to high speed, they distinguished good maneuverability and controllability for a machine of this size and mass. It was possible to make turns with a roll exceeding 60 °, and climb from a pitch angle to 50 °. At the same time, the new helicopter had a number of flaws and was still raw. A lot of complaints caused a low engine life, not exceeding the first years of operation 50 hours. At first, the helicopter pilots who had previously flown in other cars, it was difficult to get used to the retractable landing gear. They often forgot to remove the landing gear after takeoff and, even worse, release when landing. This sometimes served as the cause of very serious flight accidents.
During the control and training launches of the ATGM, it suddenly became clear that the accuracy of using this weapon was worse than on the Mi-4AB and Mi-8TV. Only every third rocket hit the target. This was largely due to the unsuccessful location of the sight and guidance equipment of the Raduga-F in the cockpit and the shading of the antenna of the command radio control line. In addition, when launching guided missiles until it hit the target, it was necessary to strictly keep the helicopter on course and altitude. In this regard, the aircrew frankly did not complain about the ATGM and preferred to use unmanaged weapons - mainly 57-mm NAR C-5, which could have 24 projectiles on Mi-128А.
A total of around 5 Mi-250А was built at the aircraft plant in Arsenyev during the 24 years. In addition to the Soviet helicopter regiments, "twenty-fours" were delivered to the allies. The Mi-24A's baptism of fire took place in 1978 during the Ethiopian-Somali war. Mi-24A with Cuban crews caused serious damage to Somali troops. Combat helicopters were particularly effective against artillery positions and armored vehicles, with the NAR being mainly used. The situation was particularly piqued by the fact that both parties to the conflict were equipped with Soviet equipment and weapons, and Mi-24A burned Soviet-made T-54 tanks. As a result, the Somali troops who invaded Ethiopia suffered a crushing defeat, and this was a considerable merit of the combat helicopters. Due to the weakness of the Somali air defense and the low preparedness of the Mi-24A calculations, those involved in the conflict did not suffer any casualties. The operation of the Mi-24A abroad continued until the beginning of the 90-s.
During the establishment of mass production designers continued to improve the weapons of the helicopter. On an experimental modification of the Mi-24B, a USPU-24 mobile machine-gun unit with a high-speed (4000-4500 rds / min) four-barreled YaKB-12,7 machine gun with a rotating barrel assembly was installed. The cartridges and ballistics of the YakB-12,7 were similar to the A-12,7 machine gun. In addition, for the new four-barreled machine gun was adopted "two-cartridge" cartridge. The new cartridge about one and a half times increased the effectiveness of the machine gun when operating on manpower. Aim shooting range - to 1500 m.
Mobile machine-gun installation USPU-24 with machine gun YaKB-12,7
The operator-controlled installation allows you to fire at an angle 60 ° in the horizontal plane, 20 ° up and 40 ° down. The machine-gun installation was controlled by the KPS-53AB aiming station. An analog computer entered the system of mobile rifle armament, coupled with sensors of onboard parameters, thanks to which the accuracy of shooting increased significantly, as corrections were entered automatically. In addition, a modernized Phalanga-P ATGM with a semi-automatic guidance system was installed on the Mi-24B. This made it possible to increase the likelihood of missiles striking the target noticeably 3 times. Thanks to the gyro-stabilized device targeting the helicopter after launching the rocket could maneuver within 60 ° along the course, which significantly increased its combat effectiveness. Several experienced Mi-24Bs in 1972 were tested. According to their results, it became clear that for a comprehensive increase in combat effectiveness, the helicopter needs a complete redesign of the cockpit.
Developments on the Mi-24B were implemented on the serial Mi-24D. Production of the twenty-four version began in 1973 year. These helicopters were exported under the designation Mi-25.
The most noticeable difference between the Mi-24D and the Mi-24А is the new cab. All crew members of the Mi-24D had isolated jobs. Starting with this model, the helicopter acquired a familiar look, for which he was nicknamed the "crocodile". The cabin 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, their bulletproofness increased, which significantly increased the chances of survival when performing an attack. Thanks to the improved aerodynamics, the helicopter flight data somewhat increased, maneuverability became higher.
ATGM “Phalanx” and blocks NAR UB-32 on the Mi-24D helicopter
In view of the unavailability of the promising Sturm ATGM on the Mi-24D, the Phalanga-P ATGM 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 did not change compared to the experienced Mi-24B. Anti-tank radio command ATGM "Phalanx" were in service in our country from 1960 to 1993 year. In a number of countries they are still used.
The most massive modification was the Mi-24В. This machine was able to introduce a new ATGM 9K113 "Sturm-V" with the guidance system "Rainbow-III". The eyepiece of the ATGM guidance system was located on the right side of the weapon operator’s cabin. On the left side there is a radiotransparent fairing for the ATGM guidance antenna.
The 9М114 “Sturm” two-stage rocket has an aiming 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 for hitting the target after the launch of an anti-tank missile system has been significantly reduced. When firing at a maximum range, the rocket’s flight time is 14 with.
ATGM “Storm” and the NAR B-8B20A unit on the Mi-24В
With a missile launch weight of about 32 kg, it is equipped with a warhead weighing a little more than 5 kg. Penetration is 500 mm of homogeneous armor at a meeting angle of 90 °. At the test site during the tests, it was possible to achieve the probability of hitting the target 0,92. According to expert estimates, during real combat operations, when a helicopter is forced to actively maneuver due to anti-aircraft resistance, the probability of hitting a tank at a distance of 3500-4000 m will be 0,6-0,8. The Mi-24В combat helicopter with the Sturm-B complex was commissioned in the 1976 year.
By the beginning of the mass production of the Mi-24В in the front-line helicopter shelves, there were already about 400 Mi-24А and Mi-24Д. Over the years, 10 serial production was transferred to the customer about 1000 Mi-24В.
Start NAR C-8 with Mi-24В
In addition to 57-mm unguided missiles, new powerful 80-mm NAR C-8 in 20-i B-8В20А charging units were included in the armament. Cumulative fragmentation unguided C-8KO missiles with armor penetration along the normal 400 mm of homogeneous armor, in the 70-s were able to ensure the effective defeat of any tanks.
Exit NAR C-8 from the starting block
Compared with 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 on a combat helicopter could be used 122-mm NAR S-13. Although the S-13 was created mainly for the destruction of capital defensive structures and reinforced concrete aviation shelters, large enough 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.
NAR C-13, five-charge B-13 unit and the “Sturm-V” ATGM in TPK near the Mi-24В
During the tests, it was found out that the fragments of the high-explosive fragmentation warhead weighing 33 kg at a distance of up to 5-10 m are able to penetrate the armor of the BTR and BMP. At the same time, after breaking through the armor, the fragments have a good incendiary effect. During the control tests against armored vehicles, as a result of a direct hit by the C-13OF, a guide and two road wheels, as well as the 3 track, were pulled out into the heavy tank EC-1,5M. Bullet proof blinds 50 mm thick on the engine compartment caved in to the 25-30 mm. The tank gun was pierced in several places. If this were a real enemy tank, he would need to be evacuated to the rear for a long overhaul. When it hit the stern of the decommissioned BMP-1, the landing party was completely destroyed. An explosion tore out three skating rinks and blew off the tower. In the salvo, when launching from 1500-1600 m, the missile dispersion at the target did not exceed 8 m. Thus, the NAR C-13 could be effectively used to attack enemy armor columns, being outside the effective range of anti-aircraft heavy machine guns.
The launch of the NAR is carried out by the pilot using the ASP-17В collimator sight, which can also be used for firing a machine gun while fixing it on the axis of the helicopter and bombing. On the Mi-24V, a suspension of four aerial bombs in caliber up to 250 kg is possible. The helicopter can take two bombs FAB-500 or incendiary tanks ZB-500, or containers KMGU-2. It is possible to simultaneously hang bombs and NAR units. On internal pylons, when operating against enemy manpower, two UPK-23-250 containers with 23-mm guns, as well as universal helicopter gondolas with 30-mm grenade launcher, or with two 7,62-mm GSHG-7,62 machine guns and one 12,7- can be placed mm machine gun YakB-12,7. In the middle of the 80-x the number of anti-tank guided missiles in a helicopter was doubled.
The Mi-24B received fairly sophisticated on-board equipment by the standards of the 70-s. Including three VHF and one HF radio station. For the first time in a combat helicopter, designed to fight tanks and direct fire support for ground units, a secret communications equipment appeared, which was used to communicate with ground-based aircraft manufacturers.
To counteract ground-based air defense systems and to protect against missiles with thermal homing heads, there was an indicator of radar exposure of the Sirena C-3M or Bereza L-006 radar, the SOEP-B1A Lipa station and a device for ejection of heat traps. In the generator of thermal noise "Lipa" 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 IR rays was formed.
Equipment of Mi-24V heat traps in Afghanistan, under the main rotor visible emitter SOEP-V1A "Lipa"
In the case of simultaneous use of “Lipy” with heat traps and GOS, in most cases it was disoriented, and the “yaw” of the rocket between the traps and the helicopter took place. The experience of combat operations demonstrated the high effectiveness of this method of protection against MANPADS. The disadvantage of the jamming station installed on the Mi-24В is the presence of a "dead zone" below and the failure to provide protection from the Stingers in this direction. The total efficiency of the Lipa optoelectronic jamming station with simultaneous use of heat traps and means of reducing IR-visibility under the conditions of Afghanistan was 70-85%.
In general, the Mi-24В 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 put a lot of effort to eliminate the design flaws and numerous "children's sores." In the second half of the 70-ies, the flight and technical staff mastered the Twenty-Fours well, and they were a formidable force that could have a significant impact on the course of hostilities. In total, in the first half of the 80s, the Soviet Army had 15 separate combat helicopter regiments. As a rule, each regiment consisted of three squadrons: two 20 Mi-24 and one 20 Mi-8. In addition, the Mi-24 were part of the individual helicopter regiments of combat control.
Продолжение следует ...
AB Shirokorad. History aviation weapons.