Ilyushin Il-4

The Ilyushin Il-4 (Cyrillic Илью́шин Ил-4, NATO reporting name: "Bob"[1] ) was a Soviet World War II bomber aircraft, widely used by the Soviet Air Force (VVS, Voenno-Vozdushnye Sily), although not well known.[citation needed] {| class="toc" id="toc"

Contents
[hide] *1 Design and development
 * 2 Operational history
 * 3 Operators
 * 4 Specifications (Il-4)
 * 5 See also
 * 6 References
 * 6.1 Notes
 * 6.2 Bibliography
 * }

Design and development
In 1938, the Ilyushin design bureau redesigned the Ilyushin DB-3 to ease production and improve performance, the revised version receiving the designation DB-3F (Forsirovannyi or "boosted"). The aircraft's internal structure, particularly the wings, was extensively changed, eliminating the need for hand finishing of the structure and with Duralumin replacing the large scale use of steel in the earlier aircraft.[2] [3] The aircraft's fuel system was redesigned, increasing capacity while reducing the number of fuel tanks.[2] The fuselage nose was lengthened to give more room for the navigator/bomb-aimer while reducing drag. The prototype DB-3F, powered by the same 708 kW (949 hp) Tumansky M-87B engines of the DB-3M, was piloted on its maiden flight by Vladimir Kokkinaki on 21 May 1939.[4] It successfully passed through state acceptance tests and entered production in January 1940, with the 1,100 hp (820 kW) Tumansky M-88 quickly replacing the M-87.[5] [6] The DB-3F was redesignated Il-4 in March 1942.[6] Some series had wooden outer wings and front fuselage to conserve metals, and throughout the production engines and fuel tanks were upgraded for more performance while keeping the same range. However the most notable change was the addition of larger defensive guns in the turret, using the 12.7 mm (0.5 in) UBT machine gun in place of the earlier 7.62 mm (0.3 in) weapons. In addition it was found that the gunners were attacked first, so blocks of armor were placed around the gunner positions.

All this extra weight wasn't offset by the newer engines however, and the Il-4 proved to be slower than the earlier versions at only 404 km/h (251 mph). An attempt to improve performance was made as the Il-6, adding large diesel engines and heavier armament. The engine proved unreliable and production was never started. The Il-4 remained in production until 1944, when just over 5,200 had been built.

Operational history
Although the Il-4 was only a medium bomber, it had the range to be used on strategic missions. The VVS wasn't terribly interested in this role, but nevertheless the Il-4 was used on several highly publicized raids against Berlin. Most would be used on much shorter range missions, often adding another 1,000 kg (2,204 lb) of bombs under the wings, in addition to the internal 2,500 kg (5,512 lb).

Finland bought four captured DB-3Fs from German stocks. These were given the Finnish Air Force serials DF-22 to DF-25 and flown from Bryansk, Russia to Finland (one aircraft, DF-22, was destroyed en route and crashed near Syeschtschinskaya airfield). The aircraft were later flown by No. 48 Sqn during 1943 (DF-23, DF-24 and DF-25), No. 46 Sqn during 1944 (DF-23 and DF-24) and No. 45 Sqn for a short time in 1945 (DF-23), until the last remaining serviceable aircraft went into depot, February 23, 1945. DF-25 got after the war lost in snowbliz, landed on the ice and crashed in to the woods in Öja near the city of Kokkola. Most parts of the plane rescued and taken to a depot.[7]

Operators
Ilyushin DB-3M with Finnish markings;China
 * Chinese Nationalist Air Force 24 aircraft
 * Finland
 * Finnish Air Force 11 aircraft of the type DB-3M and 4 aircraft of the type DB-3F (Il-4)
 * Germany
 * Luftwaffe
 * Soviet Union
 * Soviet Air Force
 * Regiments as at 1945-46:[8]
 * 10th Guards Bomber Aviation Regiment
 * 290th Bomber Aviation Regiment
 * 303rd Bomber Aviation Regiment (Zavitinsk, Amur Oblast)
 * 442nd Bomber Aviation Regiment (Belogorsk, Amur Oblast)with Il-4
 * other regiments


 * Soviet Naval Aviation

Specifications (Il-4)
Il-4 at MoscowIl-4 (1942)Data from From DB-3 To Il-4...The Soviet Long-Range Bomber[9]

General characteristics Performance Armament
 * Crew: 4 (pilot, bombardier/navigator, dorsal gunner/wireless-operator, ventral gunner)
 * Length: 14.76 m (48 ft 5 in)
 * Wingspan: 21.44 m (70 ft 4 in)
 * Wing area: 66.70 m2 (718.0 sq ft)
 * Empty weight: 5,800 kg (12,787 lb)
 * Max takeoff weight: 9,470 kg (20,878 lb)
 * Powerplant: 2 × Tumansky M-88B 9-cyl. air-cooled radial piston engines, 820 kW (1,100 hp) each
 * Maximum speed: 410 km/h (255 mph; 221 kn) at 6,500 m (21,325 ft)
 * Range: 3,800 km (2,361 mi; 2,052 nmi) (max internal fuel), 2,600 km (1,404 nmi; 1,616 mi) with 1,000 kg (2,200 lb) bombs
 * Service ceiling: 8,700 m (28,543 ft)
 * Time to altitude: 13.6 min to 5,000 m (16,404 ft)


 * Guns: * 2 × 7.62 mm ShKAS machine guns (1 in nose, 1 in ventral hatch)
 * 1 × 12.7 mm UBT machine gun in dorsal turret
 * Rockets: 2 × BETAB-750DS 305 mm rockets.[11]
 * Missiles: 1 × 940 kg (2,100 lb) Type 45-36 torpedo[10]
 * Bombs: Up to 2,700 kg (6,000 lb) of bombs or mines.