Aviation of World War II

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DB-3

Ilushin DB-3
  • Long-range bomber
  • First flight: 1935
  • Ilyushin

The DB-3 went into production at Plant No.39 in Moscow and Plant No. 18 in Voronezh. To perfect the bomber during series production, Plant No.39's experimental workshop was transformed into a design bureau, with Sergei Ilyushin as chief designer. This was simply a formality, because by that time the Ilyushin OKB had already been formed as a united team of designers capable of solving different problems concerning the development and updating of advanced combat aircraft.

From May to October 1937 pre-production DB-3 No.3039002 underwent state tests at the Nauchno Issledovatelyskii Institut (NII - scientific and research institute of the WS). Its performance proved to be slightly inferior to that of the prototype. At a weight of 14,550 lb (6,600kg) it had a sea level speed of 201mph (325km/h), attained 242mph (390km/h) at 16,100 ft (5,000m) and reached its service ceiling in 46 minutes. With such a performance the DB-3 considerably outperformed Germany's Junkers Ju86D and even the new Heinkel He 111B then under test at Rechlin. The He 111B was 6.2 to 12.4mph (10 to 20km/h) slower at all altitudes and its service ceiling was 4,600 ft (1,400m) lower, while its armament was the same and controllability and stability were better.

Not only were the DB-3's aerodynamics excellent, but its fuel and oil capacity were equal to one-third of its maximum take-off weight. As a result it had ranges of 2,485 miles (4,000km) with a 1,102 lb (500kg) bomb load and 1,926 miles (3,100km) with a bomb load of 2,204 lb (1,000kg), while the He 111В managed 1,031 miles (1,660km) with 1,653 lb (750kg) and 565 miles (910km) with 3,306 lb (1,500kg). Early in its successful life the DB-3 gained the high appreciation of its pilots. Particularly notable were its ease to take-off, rapid climb, good stability without any suggestion of yaw, steady level flight (which made it a good bombing platform), tight turns with 40° to 60° of bank, and easy landing approach. It had no dangerous tendencies such as rapid loss of speed, wing stall and arbitrary ballooning during landing. The DB-3 also had good single-engine capabilities, and at a normal flying weight of 15,432 lb (7,000kg) could climb and turn in both directions on one engine. However, pilots noted a lack of longitudinal stability owing to the generally accepted aft cg position.

In 1937, with the help of a number of Ilyushin Design Bureau designers including A Belov, V Biryulin, M Yefimenko and A Levin, the two plants manufactured 45 DB-3s, and that year the bomber was introduced into the inventory of the Soviet VVS. It considerably outperformed similar bombers built in Germany, England, France and the USA.

Its high performance, especially with regard to range, was proved during two long range flights made by the modified TsKB-30, now named Moskva, during 1938-1939. On one of these, flown on 28/29th April 1939, pilot V Kokkinaki and navigator M Gordienko covered 4,971 miles 8,000km (4,048 miles/ 6,515km in a straight line) non-stop at an average speed of 216mph (348km/h). This was a significant achievement for Soviet aviation at that time. The Moskva's long distance flights greatly influenced the development of the DB-3's airframe, engines and equipment. More over, flights by Kokkinaki and many other Soviet pilots enabled piloting techniques for long range flights to be developed and revealed the crew fatigue limits. These aspects also promoted efficient weather survey and communication services.

All of this elevated the combat capabilities of Soviet long range aviation, based at that time on different variants of the DB-3, which was constantly being improved. In 1938 the M-85 engine was replaced by the M-86 with an augmented rating of 950hp (708kW) This allowed the DB-3's good take-off performance to be retained in spite of increased weight. The maximum speeds at an various altitudes remained the same. From 1938 the bomber's speed was increased by the installation of M-87As and the use of VlSh-3 variable-pitch propellers instead of fixed-pitch units, which meant that engine power was used to best advantage during different phases of flight. The M-87A, which had the same take-off power as the M-86, provided 800hp (596kW) at an altitude of 15,500 ft (4,700m).

During tests at the NII VVS early in 1939, two bombers produced at Plants Nos.18 and 39 demonstrated improved performance. At a flying weight of 15,873 to 17,195 lb (7,200 to 7,800kg) their sea level speeds were equal to 265 to 270mph (428 to 436km/h) at a critical altitude of 16,300ft (4,960m). The service ceiling had increased to 30,200 to 30,500 ft (9,200 to 9,300m), and the time to climb to 16,400ft (5,000m) was 10.7 minutes. The take-off run was 1,148 to 1,312 ft (350 to 400m) and the maximum overloaded weight had risen to 21,375 lb (9,696kg). In the final test report it was noted that the aeroplanes produced by Plant No.39 were of higher quality. In 1938 another factory, No.126 in Komsomolsk, was also converted to DB-3 production, increasing output by 400 aircraft.



Ilyushin's long-range bombers
DB-3 DB-3F IL-4
Crew 3 4 4
Year of issue 1939 1940 1941
Dimensions
Length, m 14.22 14.76 14.76
Wing span, m 21.44 21.44 21.44
Wing area, m² 65.6 66.7 66.7
Weight, kg:
Loaded weight 7450 8030 9470
Maximum takeoff weight 9450 10150 11570
Powerplant
Engine М-87 М-88 М-88B
Power, hp 2x950 2x1100 2x1100
Performance
Maximum speed, km/h at altitude 439 429 422
m 4900 6600 6800
Service ceiling, m 9600 9700 8900
Service range with normal bomb load, km 3800 3300 3800
Armament
Bomb load, kg Normal 1000
Maximum 2500 2500 2500
Defensive Armament Machine guns 3 3 3
Cannon - - -
Photo Description
Drawing DB-3 2 × M-85 Drawing DB-3 2 × M-85
The DB-3 with the M-85 engines The DB-3 with the M-85 engines.
The DB-3, captured by the Finns The DB-3, captured by the Finns

Bibliography

  • "The history of designs of planes in USSR 1938-1950" /Vadim Shavrov/
  • "Planes of Stalin falcons" /Konstantin Kosminkov and Dmitriy Grinyuk/
  • "Planes of Ilyushin`s design bureau" /Genrih Novojilov/
  • "The Soviet planes" /Alexander Yakovlev/