DB-A (Far Bomber-Academy)
Heavy four-engine bomber DB-A (Far Bomber-Academy) was developed under the guidance of the teacher of the Zhukovsky institute, V.F. Bolkhovitinov. The aircraft was a deep modification of the TB-3 bomber designed by AN Tupolev and was intended as its replacement.
The collective of the aircraft factory that produced the TB-3 aircraft proposed to modernize this heavy bomber in order to significantly increase its speed and ceiling. The initiative was supported. To help workers and engineers of the plant came teachers of the Air Force Academy. N.E. Zhukovsky. The group was headed by Professor Viktor Fedorovich Bolkhovitinov (1899 -1970). The work was carried out at a high pace and at the beginning of 1936, two aircraft, which received the letters DB-A , climbed into the air.
Viktor Fedorovich Bolkhovitinov (1899-1970)-one of the first graduates of the military Air Engineering Academy. N. E. Zhukovsky, unchanged for almost 45 years worked in it as a teacher, then a professor, head of the Department of Aircraft Designs; He led in addition and a great work on new aircraft, heading the design team Vvia, then-his bureau at the factory, where he was the director. Design activity of V. F. Bolkhovitinov lasted thirteen years from 1934 to 1946 the first work was a plane db-A, then there were seven more, some of which were not finished or remained in the projects.
In 1933-1934, in the serial construction of the aircraft TB-3, there was a thought to overhaul the aircraft or to release a new one on its basis in order to achieve a significant improvement in its performance in light of the new requirements. Plant on its own initiative, supported by Commander, invited a group of teachers and Engineers of the Air Force Academy (about 20 people) to perform this work. Viktor Fedorovich Bolkhovitinov headed the group; The group included M. M. Flack (construction and calculations for strength), I. M. Kurickes (aerodynamics), etc. In 1934, the plant was organized by the design bureau, where two copies of the new aircraft were designed and constructed very quickly. A. N. Tupolev from this work refused, as he designed more advanced TB-7.
According to the scheme and dimensions, the new long-range bomber hardly differed from TB-3. It also had four M-34RN engines, but its aerodynamics were significantly improved: the corrugated casing was everywhere replaced by a smooth one, the cabins and rifles were closed, the bomb suspension was only internal, and the chassis with semi-scraped wheels was covered with fairings.
The plane was released in November 1934, the first flight-in May 1935 by March 5, 1936 was carried out its factory tests (pilots N. G. Kastanaev and I. N. Moses), continued as a state in May-June of the same year. At a flight weight of 19500 kg the horizontal flight on two engines at height of 2500 m was possible, on three engines the ceiling was 5100 m. Aircraft DB-A showed advantages over TB-3. Speed was more on 42-50 km/h, takeoff was 400 m, mileage 300 m, landing speed 85 km/h. After elimination of a number of shortcomings of tests were repeated with engines of AM-34 rnv, the plane again has passed tests and has been considered quite successful.
November 10, 1936 pilots M. A. Njuhtikov and M. A. Tacky raised on this plane cargo 10 tons at a height of 7032 m, and November 20-cargo 13 T to a height of 4535 m, setting two international records. May 14, 1937 pilots G. F. Bajdukov and N. G. Kastanaev with Navigator-operator L. L. Kerberom carried out a flight on the route Moscow-Melitopol-Moscow on distance 2002.6 km for 7 H 2 min 11.7 with the control cargo of 5 T, having established two international records of Speed 280 and 246 km/h at distances of 1000 and 2000 km with a load of 5 T.
The successes of the aircraft led to the idea of applying it for the transarctic flight across the North Pole to America. On the same first instance of the aircraft, receives the designation N-209, some constructive improvements were made. The flight started on August 12, 1937 from Moscow, was conducted in difficult weather conditions. On 13 August at 13 h 40 min The plane passed over the North Pole, and at 14 h 32 min from the plane was received the last telegram with the message that one of the engines Stopped. The connection was broken. The plane was never found, despite long and thorough searches for almost a year. This flight had not been carefully prepared.
Despite the death of the first instance, the work on the aircraft continued. On the second plane were installed engines am-34 NGF with turbochargers, and in 1938 were held tests (pilot M. A. Njuhtikov). A series of 16 aircraft was laid, of which 12 aircraft were handed over in 1939. In 1940, production was stopped due to the launch of a series of aircraft TB-7, unflappable significantly higher flight qualities.
The plane DB-A was only a transient type to the high-speed heavy bomber. But because of the fact that the plane TB-7 was released with big breaks and twice was removed from production, and then again restored, was even thought to release a few more Series DB-A.
In March 1936, Bolkhovitinov had a project of the transport aircraft with four engines M-34 NGF in 1200 L. S., wingspan-36.2 m, length 26.0 m, wing area-180 m2, hermetic cabins, flight weight 20 000-27 000 kg, weight return-38%, specific load on wing 11 1-150 kg/m2, power-5-6.7 kg/L. S., speed near the earth 350 km/h at an altitude of 4000 m-400 km/h, at an altitude of 8000 m-460 km/h, ceiling 9.0-11.0 km, time set height 5000 m-10.5 min, 8000 m-17.4 min. The aircraft for the project was similar to the TB-7 bomber but was not built, although it was listed in the 1938 plan.
In December, 1939 the Tactical and technical requirements (TTT) were developed for the heavy cruiser TC-1-Modification DB-2a with four engines M-34 NGF, with powerful armament (3 guns ShVAK, 5 machine guns ShKAS and 8 RS) with unprecedented ammunition (3,000 shells and 11 thousand rounds). For a similar aircraft TC-4 were assigned: Crew-11 people, bombs-5000 kg and flight weight from 16 880 to 23 900 kg. The planes were not built on these requirements.
|Height, meters||No data available|
|Wing area, M2||230|
|Weight of empty, kg||15400|
|Weight normal takeoff, kg||21900|
|Weight of full load, kg||6500|
|Power Plant||4ham-34 ph|
|Volume of fuel tanks, liters||14000|
|Power, HP, KW||4 970 (4 713)|
|Cruising speed, km/h||No data available|
|The maximum speed of km/h at the ground||280|
|Maximum speed km/h, M||330 at 4000|
|Wing load, kg/2||95|
|Length of mileage, meters||300|
|Length of run, meters||400|
|Practical range, km||4500|
|Practical Ceiling, M||7220|
|Weapons, machine guns, MM||6x 7.62|
|Weapons, guns, MM||1h20|
|Bomb load, kg||5000|
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