The Ilyushin Il-2 (Russian: Илью́шин Ил-2) is a ground-attack plane that was produced by the Soviet Union in large numbers during the Second World War. The word shturmovík (), the generic Russian term for a ground-attack aircraft, became a synecdoche for the Il-2 in English sources, where it is commonly rendered Shturmovik, StormovikStapfer, 1995 and Sturmovik.Rastrenin, 2008
To Il-2 pilots, the aircraft was known by the diminutive "Ilyusha". To the soldiers on the ground, it was called the "Hunchback", the "Flying Tank" or the "Flying Infantryman". Its postwar NATO reporting name was Bark.Gunston 1995, p. 106.
During the war, 36,183 units of the Il-2 were produced, and in combination with its successor, the Ilyushin Il-10, a total of 42,330Jane's 1989, p. 529. were built, making it the single most produced military aircraft design in aviation history, as well as one of the most produced piloted aircraft in history along with the American postwar civilian Cessna 172 and the German contemporary Messerschmitt Bf 109.
The Il-2 played a crucial role on the Eastern Front. When factories fell behind on deliveries, Joseph Stalin told the factory managers that the Il-2s were "as essential to the Red Army as air and bread".Hardesty 1982, p. 170.
Design and development
Origins
The idea for a Soviet armored ground-attack aircraft dates to the early 1930s, when Dmitry Pavlovich Grigorovich designed TSh-1 and TSh-2 armored biplanes. However, Soviet engines at the time lacked the power needed to provide the heavy aircraft with good performance. The Il-2 was designed by Sergey Ilyushin and his team at the Central Design Bureau in 1938. TsKB-55 was a two-seat aircraft with an armoured shell weighing , protecting crew, engine, radiators, and the fuel tank. Standing loaded, the Ilyushin weighed more than ,Gunston 1995, p. 104. making the armoured shell about 15% of the aircraft's gross weight. Uniquely for a World War II attack aircraft, and similarly to the forward fuselage design of the World War I-era Imperial German Junkers J.I armored, all-metal biplane, the Il-2's armor was designed as a load-bearing part of the Ilyushin's monocoque structure, thus saving considerable weight. The prototype TsKB-55, which first flew on 2 October 1939, won the government competition against the Sukhoi Su-6 and received the VVS designation BSh-2 (the BSh stood for "Bronirovani Shturmovik" or armoured ground attack). The prototypes – TsKB-55 and TskB-57 – were built at Moscow plant #39, at that time the Ilyushin design bureau's base.
The BSh-2 was overweight and underpowered, with the original Mikulin AM-35 engine designed to give its greatest power outputs at high altitude. Because of this, it was redesigned as the TsKB-57, a lighter single-seat design with the more powerful Mikulin AM-38 engine, a development of the AM-35 optimised for low-level operation.Green and Swanborough 1980, p. 2. The TsKB-57 first flew on 12 October 1940. The production aircraft passed State Acceptance Trials in March 1941, and was redesignated Il-2 in April.Gunston 1995, pp. 105–106. Deliveries to operational units commenced in May 1941.Green and Swanborough 1980, p. 3.
The armament of Il-2 was subject to a competition. One of the first 1940 photographs of the Il-2 show it equipped with two MP-6 23 mm autocannons developed by Yakov Taubin (Яков Таубин) at OKB-16. The MP-6 gun weighed and developed an initial muzzle velocity of . It operated on the short recoil principle and had a rate of fire of about 600 rpm. (The development of the MP-6 gun can be traced back to 1937. The initial version was tested in the spring of 1940 on a Messerschmitt Bf 110 bought from Germany, because there was no suitable Soviet aircraft on which to mount it. In the summer of 1940 it was tested on the Pashinin I-21.) Factory trials of the MP-6 gun on the Il-2 were conducted in August 1940. In the early Il-2 prototypes, these guns were fed by 81-round clips. In flight, these clips sometimes became dislodged because of their large surface, which caused them to experience significant aerodynamic pressure. Competitive tests were conducted in the spring of 1941 between the MP-6 gun modified to belt-fed and the newly developed, gas-operated Volkov-Yartsev VYa-23, which had otherwise rather similar characteristics. The VYa-23 was declared the winner at this trial. Subsequently, in May 1941, development of the MP-6 gun was terminated. Taubin was arrested and summarily executed in October that year for plotting to continue production of his failed weapon.
Technical description The Il-2 is a single-engine, propeller-driven, low-wing monoplane of mixed construction with a crew of two (one in early versions), specially designed for assault operations. Its most notable feature was the inclusion of armor in an airframe load-bearing scheme. Armor plates replaced the frame and paneling throughout the nacelle and middle part of the fuselage, and an armored hull made of riveted homogeneous armor steel AB-1 (AB-2) secured the aircraft's engine, cockpit, water and oil radiators, and fuel tanks.
The extreme survivability of the Il-2 Sturmovik—frequently termed the "Flying Tank"—was made possible by a revolutionary approach to armored protection engineered by VIAM metallurgists Sergey T. Kishkin and Nikolai M. Sklyarov. Rather than simply bolting heavy armor plates onto an existing airframe, Kishkin and Sklyarov designed a load-bearing, highly complex armored shell made of heterogeneous and homogeneous steel plates that functioned simultaneously as the aircraft's forward structural fuselage and fuel tank protection. This armor could deflect high-explosive and armor-piercing rounds from German autocannons without shattering.
Production In early 1941, the Il-2 was ordered into production at four factories, and was eventually produced in greater numbers than any other military aircraft in aviation history, but by the time Nazi Germany invaded the Soviet Union on 22 June 1941, only State Aviation Factory No. 18 at Voronezh and Factory No. 381 at Leningrad had commenced production, with 249 having been built by the time of the German attack.Gordon, Komissarov and Komissarov 2004, p. 18.
Production early in the war was slow because after the German invasion the aircraft factories near Moscow and other major cities in western Russia had to be moved east of the Ural Mountains. Ilyushin and his engineers had time to reconsider production methods, and two months after the move Il-2s were again being produced. The tempo was not to Premier Stalin's liking, however, and he issued the following telegram to Shenkman and Tretyakov:
As a result, "the production of Shturmoviks rapidly gained speed. Stalin's notion of the Il-2 being 'like bread' to the Red Army took hold in Ilyushin's aircraft plants, and the army soon had their Shturmoviks available in quantity."
State Aviation Factory No. 1, which was evacuated from Moscow to Kuibyshev (now Samara), came online in October 1941 and would ultimately produce 11,863 Il-2s over four years while also producing smaller numbers of MiG-3s and the Il-2s successor, the Il-10, at the same factory.
Operational history
Initial use and operational confusion The first use in action of the Il-2 was with the 4th ShAP (Ground Attack Regiment) over the Berezina River days after German invasion began.Gordon, Komissarov and Komissarov 2004, p. 38. The aircraft was so new that the pilots had no training in flight characteristics or tactics, and the ground crew no training in servicing or re-arming. The training received enabled the pilots only to take-off and land; none of the pilots had fired the armament, let alone learned tactics. There were 249 Il-2s available on 22 June 1941. In the first three days, 4th ShAP had lost 10 Il-2s to enemy action, a further 19 were lost to other causes, and 20 pilots were killed.Bergstrom 2007, p. 26. Cites document "TsAMO f. 319, op.4799d.25." Russian Central Military Archive at Podolsk. By 10 July, 4th ShAP was down to 10 aircraft from a strength of 65.Shores 1977, p. 73.
New tactics Tactics improved as Soviet aircrews became used to the Il-2's strengths. Instead of a low horizontal straight approach at altitude, the target was usually kept to the pilot's left and a turn and shallow dive of 30 degrees was used, using an echeloned assault by four to twelve aircraft at a time. Although the Il-2's RS-82 and RS-132 rockets could destroy armored vehicles with one hit, they were so inaccurate that experienced Il-2 pilots mainly used the cannon.Shores 1977, pp. 72–82. Another potent weapon of the Il-2 were high-explosive anti-tank (HEAT) shaped charge bomblets named protivotankovaya aviabomba (PTAB, "anti-tank aviation bomb"). They were designated PTAB-2.5-1.5, as they had a total weight of , and an explosive charge of . Up to 192 were carried in four external dispensers (cluster bombs) or up to 220 in the inner wing panels' internal ventral weapon bays. The charge could easily penetrate the relatively thin upper armor of all heavy German tanks. PTABs were first used on a large scale in the Battle of Kursk.
The Il-2 was thereafter deployed widely on the Eastern Front. The aircraft could fly in low light conditions and carried weapons able to defeat the thick armor of the Panther and Tiger I tanks.
Effectiveness as attack aircraft
The true capabilities of the Il-2 are difficult to determine from existing documentary evidence. W. Liss in Aircraft profile 88: Ilyushin Il-2 mentions an engagement during the Battle of Kursk on 7 July 1943, in which 70 tanks from the German 9th Panzer Division were claimed to be destroyed by Ilyushin Il-2s in just 20 minutes.Liss 1966 In another report of the action on the same day, a Soviet staff publication states that:
In the Battle of Kursk (Operation Citadel), General V. Ryazanov became a master in the use of attack aircraft en masse, developing and improving the tactics of Il-2 operations in co-ordination with infantry, artillery and armored troops. Il-2s at Kursk used the "circle of death" tactic: up to eight Shturmoviks formed a defensive circle, each plane protecting the one ahead with its forward machine guns, while individual Il-2s took turns leaving the circle, attacking a target, and rejoining the circle. Ryazanov was later awarded the Gold Star of Hero of Soviet Union twice, and the 1st Assault Aviation Corps under his command became the first unit to be awarded the honorific title of Guards.Gordon 2008, p. 296. In 1943, one aircraft was lost for every 26 Shturmovik sorties. About half of those lost were shot down by fighters, the rest falling to anti-aircraft fire.
Other studies of the fighting at Kursk suggest that very few of German armour losses were caused by the IL-2 or any other Soviet aircraft. In fact, total German tank losses in Operation Citadel amounted to 323 destroyed, the vast majority by anti-tank guns and armored fighting vehicles.D. M. Glantz, J.M. House. The Battle of Kursk. Ian Allan Publishing Ltd, Surrey, UK, 1999, p. 349. In addition, it is difficult to find any first-hand accounts by German panzer crews on the Eastern Front describing anything more than the occasional loss to direct air attack. The vast majority, around 95–98%, of tank losses were due to enemy anti-tank guns, tanks, mines, artillery, and infantry assault, or simply abandonment as operational losses (due to causes such as mechanical breakdown or running out of fuel), which mostly happened during the last eleven months of the war.