Iljušin DB-4

History:

Sergei Vladimirovich Ilyushin had worked since the second half of the thirties in the CKB (Centrlnoje Konstruktorskoje Bjuro) in Moscow. Besides the many other aircraft he fashioned a fairly successful long-range bomber DB-3 (TSKB-30). Iljušinově the design office, it was clear that for the coming forty years, bud should be a long-range bomber to fundamentally improve, to accomplish as much with his performances. Recorded the fact and another fact – at the very end of the thirties it seemed that the motorář And. And. Mikulin will soon complete the development of-high-performance the height osmnáctiválce M-120, the engine featured an unusual construction, its cylinders were arranged in an inverted "Y". Since this engine was expected to power around 1 350 kW, installation of such engines would be bomber obtained the good performance and good carrying capacity of bombs. These engines like to use in their bombers also other design offices and so next Iljušinova project DB-4 (TSKB-56) there are additional projects Tupolev 103-D, Mjasiščev DB-102 and Jermolajev DB-240.

Unfortunately, the motor M-120 made it seem far from the calculated performance and eventually stayed built in few specimens. The first prototype of the Ilyushin DB-4 (TSKB-56) received two such engines and started with them passing the test, the engines were also unreliable and so were built another high-rise engines Mikulin AM-37 performance 1 043 kW, the installation was fairly simple, because it was a smaller dvanáctiválcové engines. With these new engines launched a test pilot In the. To. Kokkinaki first years ago. Test flights were conducted at the factory level, but they suspect that the plane will have good flight characteristics, directional instability removed the design team for the second prototype assembly of one SOP of a larger area (the first prototype had a double). The second prototype also had a bigger defensive armament – on the back of the trunk had a gun turret with dvacetimilimetrovým cannon ŠVAK.

The performances of the airplane, due to less powerful engines, compared to the originally calculated, of course, declined, but With. In. Ilyushin assumed that the later these engines will replace engines And. D. Švecova e.g. osmnáctiválci AL-71 or promising čtrnátiválci AL-82, but in the summer of 1941 was not yet their performance is completed. Air force after Iljušinovi wanted to new aircraft introduced into production, but that again did not have suitable engines that would use the potential of the airframe. Everything finally solved the state committee of defense, which after the ambush of the USSR ended the development of many prototypes of planes and also soon stopped production of high-altitude engines AM-37. Prototype workshop in Moscow were evacuated behind the Ural mountains and their task was to improve the battle Il-2 and renovation , Il-4 Il-6 diesel engines AC-30B.

sources:
L+K no 22 / 1984, Václav Němeček, Aircraft 39-45, Ilyushin CKB/DB-4
http://www.airwar.ru/enc/bww2/db4.html.