Ilyushin Il-4 "Bob"
The Ilyushin IL-4 started life as a major upgrade to the DB-3 planned in 1938.
While outwardly similar to the DB-3, the new model was a complete redesign, incorporating the new constuction methodologies of Douglas in the USA. This meant the new DB-3F (Forced/intensive) could be assembled in less than half the manhours of the oiginal DB-3.
Production stated in 1939, and the original dorsal turret was quickly replaced with the definitive enlarged version. Problems with engine cooling led to reworked cowlings and oil cooling, and by 1941 the decision was made to cancel further production in favour of the Yer-2.
The disruption of Barbarossa saved production, and new aircraft featured an uparmoured dorsal turret with a higher calibre gun, and in 1942 the aircraft was redesignated as the Il-4.
In 1943 the troublesome M-87 engine was finally replaced by the M-88, and reinforcing strips were added along the sides of the fuselage.
In parallel with the standard bomber version, Ilyushin produced a torpedo-bomber version as the Il-4T from 1941. Externally the IL-4T was almost identical to the standard aircraft, although many had enlarged nose windows for better visibilty when launching torpedos.
In 1942 a high altitude pressurised version was designed, the IL-4TK (Turbo Kompressor). As the Soviets gained air superiority the need for the aircraft waned and the project was cancelled.
Il-4's emained in service until 1952, and two years later in 1954 NATO gave the reporting name "Bob" to the aircraft.
The DB-3's entered service in bare metal.
In 1940 the aircraft stated to be delivered painted in the initial plain green/blue camouflage scheme, while aircraft already in service received a splotchy hand spotting of green over the bare metal, but like most Soviet types this did little to help and the DB-3F's suffered heavy losses in Barbarossa. Later aircraft followed in the standard Soviet camouflage patterns, including winter whiting.
The Il-4TK existed only as a single prototype. The engine superchargers were problematic and the aircraft's best altitude was 1700m lower than projected. As the threat to Soviet bombers receded as the Soviets went on the offensive the aircraft was scapped.
