The mount of numerous Guards units, the Ilyushin Il-2 fully deserves its place in history. Not only was it built in larger numbers than any other combat aircraft in World War 2, but to the people of the Soviet Union it represented a symbol of their resistance to Nazi aggression. As a specialised ground attack aircraft, with armour protection for the crew and vital systems, it was one of the conflict’s most decisive weapons.
Yet the Il-2 was not a highly sophisticated machine. In fact, with its mixed wood and metal construction, it was comparatively crude, but this made it easy to produce using relatively unskilled labour. Outstandingly robust, it could absorb considerable battle damage, but although undemanding to fly, it was not a nimble performer, and was consequently highly vulnerable to fighter attack in the early war years. In the late 1930s, the Soviets were placing much emphasis on ground attack aircraft. While experience in Spain and China had confirmed their effectiveness, it had also demonstrated that such aircraft needed protection against ground fire. In January 1938, Ilyushin and his team put forward ideas for a dedicated attack aircraft. Designated TsKB-55, it was a two-seater powered by a supercharged AM-35 engine, with the crew, fuel and oil systems protected by armour plate varying in thickness from 4 mm up to 8 mm. Four 100-kg bombs could be carried in internal bays, with an additional pair hung from underwing racks.
The design was accepted and two prototypes were ordered, the first making its maiden flight on 2 October 1939 and the second following on 30 December. During State acceptance trials, the aircraft was found to be underpowered, but with the fitment of the specially-developed low altitude unsupercharged AM-38 engine, and the deletion of the gunner’s position, test pilots reported a major improvement in performance.
Fixed armament comprised two 23 mm PTB-23 cannon and two 7.62 mm SkHAS machine guns, with eight launching rails for rocket projectiles fitted beneath the wing outer panels. In this form the aircraft was cleared for service, and the first production Il-2 was completed by Zavod No 18 at Voronezh. It flew for the first time on 10 March 1941, just three months after the drawings had been delivered to the factory.
Although in full-scale production by the time of the German invasion on 22 June 1941, only 70 of the 249 Il-2s built up to then were actually in service. Production increased rapidly, however, and during the second half of 1941, 1293 left various factories in the USSR.
The first offensive mission mounted by a Shturmovik unit was flown on 1 July during the fighting around the city of Bobruysk and along the Berezina River. Heavy losses were inflicted by German fighter pilots during these operations, the Jagdwaffe units having quickly discovered the Il-2’s blind spots. Soviet ground attack units in turn called on Ilyushin to build a two-seat variant with a gunner operating a flexibly-mounted 12.7 mm BT machine gun. This version started rolling off the assembly lines in 1942, and some earlier single-seat machines were also converted.
By 1943 one-third of all Soviet-built combat aircraft in frontline service were Il-2s. When production ended in November 1944, 36,163 Shturmoviks had been built.
The early two-seater prototype proved to be too heavy for the limited power of the early AM-35 engine. A redesigned single-seat version was soon developed and saw combat, particularly in the early phase of the war in the Soviet Union. While the Il-2 proved to be a deadly air-to-ground weapon, heavy losses were caused by its vulnerability to fighter attack. Consequently, in February 1942, the two-seat design was revived. The Il-2M, with a rear gunner under the stretched canopy, entered service in September 1942 with the surviving single-seaters eventually modified to this standard. Later changes included an upgrade from 20 mm to 23 mm or 37 mm cannons, aerodynamic improvements, use of wooden outer wing panels instead of metal and increased fuel capacity. In 1943, the Il-2 Type 3 or Il-2m3 came out with redesigned “arrow-wings” that possessed leading edges that were swept back 15 degrees on the outer panels, and nearly straight trailing edges, resulting in a wing planform somewhat like the AT-6 trainer. Performance and handling were much improved from the resulting shift of the Il-2’s aerodynamic center rearwards with the revised “arrow wing” planform to correct the earlier problem, and this became the most common version of the Il-2. A radial engine powered variant of the Il-2 with the Shvetsov ASh-82 engine was proposed in 1942 to remedy projected shortages in the Mikulin inline engines. However, the ASh-82 was also used in the new Lavochkin La-5 fighter which effectively secured all available engines to the Lavochkin bureau. The radial engine Sukhoi Su-2 ground attack aircraft was produced in small quantities, but was generally considered unsuitable due to inadequate performance and lack of defensive armament.
- Two-seat prototype, AM-35 engine, first flight on 2 October 1939.
- VVS designation for TsKB-55 prototype.
- Single-seat prototype, AM-38 engine, first flight on 12 October 1940.
- Il-2 (TsKB-57P)
- Single-seat serial aircraft, AM-38 engine, first flight on 29 December 1940, some delivered to combat units in May–June 1941. Renamed the Il-2 in April 1941. Cannons 20 mm ShVAK or 23 mm VYa-23 (depending on which factory the Il-2 was manufactured in).
- Il-2 two-seat
- Two-seat version, AM-38 engine, first action on 30 October 1942 near Stalingrad. Maximum bomb load reduced from 600 kg to 400 kg. Used on edges of flight formations for defense against German fighters. Quickly replaced by the “Il-2 production of 1943”.
- Il-2 production of 1943
- Referred in the west as the “Il-2M”. Powered by an upgraded AM-38F engine. Delivered to the front units from early 1943. In 1943, the 20 mm ShVAK armed Il-2s faded out, leaving only the 23 mm VYa variant.
- Il-2 with NS-37
- Referred in the west as the “Il-2 Type 3M”. Based on the two-seat Il-2, armed with Nudelman-Suranov NS-37 in conformal gun pods under the wings, instead of the 20/23 mm cannons, this version is an attempt to create an anti-tank aircraft, first used in combat during the Battle of Kursk. However, the combat effectiveness was quite low and production of the variant was limited to about 3,500. Moreover, bomb load was decreased from 600 kg to 200 kg. It was replaced by the conventional Il-2 attackers armed with cassettes with cumulative bomblets.
- Il-2 production 1944 “wing with arrow”
- Referred in West as “Il-2M3” or “Il-2 Type 3”. As more duralumin became available for the Soviet aviation industry, the Il-2 received a set of all-metal wing panels. At the same time, the outer wing planform was swept back, with a straight trailing edge, since the centre of gravity was shifted rearwards after the gunner was added. The wing planform change regained controllability of the two-seat Il-2 back to level of the single-seat Il-2.
- Training version, also known as UIl-2.
- Torpedo bomber version for the Soviet Navy with the VYa-23 cannons removed to save weight, it was able to carry a single 45 cm (18 in) torpedo. Evidently, it was only a design as the 23rd Attack Air Regiment of the Black Sea Fleet flew regular Il-2M-3s fitted with torpedo racks as a field modification, and that no such aircraft were ever noted in the battle sortie logs.
- Armoured fighter, prototype only. Concept based on several dogfights between Il-2 and Luftwaffe bombers. Proved infeasible due to its low speed which causes it to only be able to intercept older Luftwaffe bombers.
- Il-2 with M-82
- A backup project prepared while plants producing AM-35/AM-38 were evacuated. Trials demonstrated that with the fighter engine, low-altitude performance and controllability were unacceptable.