Tupolev SB-2

Tupolev SB (ANT-40)
Tupolev SB of the Finnish Air Force (around 1941)
Type:	bomber
Design country:	Soviet Union
Manufacturer:	Tupolev / ZAGI
First flight:	October 7, 1934 (ANT-40/1) December 30, 1934 (ANT-40/2)
Commissioning:	1935
Production time:	1935 to 1941
Number of pieces:	6656

The Tupolev SB ( Russian Туполев СБ-2 , factory designation ANT-40 , АНТ-40), usually referred to in its versions as SB-2, was developed in the early 1930s and during the Spanish Civil War and among other conflicts in World War II deployed twin-engine Soviet bomber . On its maiden flight in 1934, it was still one of the most modern and fastest models in its class, but with the development of more modern fighters in the second half of the 1930s it quickly became obsolete and from 1943 onwards it was only used for training and communication purposes. In addition to the bomb version there was also a few copies PS-40 called passenger and one as Ar-2 designated dive bomber version.

history

The Tupolev SB was developed from 1933 by a design team under the direction of Alexander Archangelski , which was subordinate to OKB Tupolew , which in turn was a department of the ZAGI . Therefore, the two prototypes were traditionally the abbreviation "ANT" what the initials of A nThree N ikolajewitsch T upolew corresponded. The machine, known as ANT-40/1 (also SB 2RZ, Russian abbreviation for Wright Cyclone) was powered by two American radial engines Wright Cyclone with 700 HP each, while the ANT-40/2 (also SB 2IS, Russian abbreviation for Hispano-Suiza) was equipped with French Hispano Suiza 12Ybrs V12 engines .

The test program with prototype No. 1 of the ANT-40 began on October 7, 1934 under the official designation SB ( S korostnyi B ombardirovschtschik , Скоростной бомбардировщик , high-speed bomber ), No. 2 followed on December 30 of the same year. After the tests, it was decided to go for the second test model of the SB, which underwent state acceptance from February to August 1935 and was then immediately put into series production, which has now been prepared. The Klimow M-100 , a licensed version of the Hispano-Suiza 12Ybrs, was installed, which is why the aircraft was called the SB 2M-100 . A little later the self-improved M-100A was used; the designation of these copies is SB 2M-100A . From these names, which were often used at the time, the name Tupolev SB-2, which is still very widespread today, arose with the engine names omitted.

The Tupolev SB was when they appeared in the first half of the 1930s due to its all-metal construction of the most modern aircraft of its kind. For the first time in the Soviet Union were doing aerodynamic, smooth verplankte support and hull surfaces instead of the usual corrugated iron construction used . With a top speed of over 400 km / h, it flew faster than most fighter planes of the time, which in most cases were still biplanes . Equipped with a retractable landing gear was also very modern in the early 1930s , which significantly improved aerodynamics and thus flight performance .

When the Spanish Civil War broke out, the Soviet Union delivered 210 SBs to support the Air Forces of the Spanish Republic ( Fuerzas Aéreas de la República Española - FARE) from October 1936 , some of which were flown by Soviet volunteers. During this war she was nicknamed "Katyushka" by the Spanish. Because of its similarity to the American Martin B-10 , the SB was often confused with this and therefore referred to as Martin .

Taking into account the experiences from this conflict, Alexander Archangelski constructed the SB into a dive bomber in 1938. To do this, he reduced the wing area and the tail unit, equipped the fuselage with a new, tapered nose pulpit and installed dive brakes under the wings. The engines were given aerodynamically more favorable fairings. This type, known as Archangelski Ar-2 , flew for the first time in 1939 and 200 machines were built by 1941.

The SB was also used from July 1937 in the Second Sino-Japanese War , in 1938/1939 in the Japanese-Soviet border conflict and in 1939/1940 in the Soviet-Finnish winter war .

At the beginning of the Second World War, the versions of the SB were already out of date and were replaced from service at the front in December 1941. Numerous examples were used as bombers in the front until 1943, when they were finally relocated to the rear lines only for training and connection purposes.

In Czechoslovakia (ČSR), 111 copies of this model were manufactured under license under the designation Avia B-71 from 1938 onwards, some of which were also used in the Wehrmacht air force or passed on to allied states after the occupation of Czechoslovakia in April 1939 during World War II . The aircraft was continued to be built under German direction in an unknown number at the Avia plant .

Airliner version of PS-40 of Aeroflot

There were some machines used as passenger and mail planes under the designation PS-40 for the state airline Aeroflot , which could carry five passengers. A school version was used under the name USB or SB-2U .

The SB also served as a test vehicle in numerous experiments. For example, a nose wheel landing gear with adjustable geometry was attached to an SB-2bis under the direction of Igor Tolstych and tested in 1940 by Mark Gallai . A camera was located under the fuselage on a suspension that filmed the nose wheel during the take-off and landing phases. This machine was given the unofficial name "Pterodactyl" by the pilots (from the prehistoric pterosaur Pterodactylus ).

A total of 6656 copies of the Tupolev SB were built in the Soviet Union.

variants

designation	features
ANT-40	Name of the development office, also called ZAGI -40 .
SB 2M-100	Basic series version equipped with two M-100 motors and two-bladed WISch-2 propellers. The passenger version was called PS-40 (Passaschirskij Samoljot).
SB 2M-100A	Further development with two M-100 A motors
SB 2M-103	More powerful further development from 1936 with two M-103 engines and three-bladed WISch-22 propellers. A civilian passenger version was designated as the PS-41 .
SB 2M-103A	Further development from 1937 with two M-103A engines.
USB	Training version with an extended fuselage nose and an additional open cockpit for the flight instructor and double controls.
Arkhangelsky Ar-2	Further development from 1938, see text. Compared to the conventional SB, it had a larger fuel supply and a higher bomb load. Project name SB-RK
Arkhangelski SBB-1	Prototype of a fast close-range bomber from 1939 based on the SB-2 further development MMN with shortened wings and modified, more strongly glazed bow. The machine, also known as Project B , had a shortened fuselage and an attached pilot's cabin. The tests took place in early 1941, in favor of the Pe-2 there was no series production.
Avia B-71	Czechoslovak license production, 111 units built.

commitment

Spanish Air Force SB, 1940

In the Spanish Civil War , the 210 SB 2M-100 and M-100A, which were delivered to the Republicans from October 1936 and some of which were flown by Soviet volunteers, proved to be quite effective at the beginning, as they were in most cases faster than the opposing fighters the nationalists were. However, this advantage was quickly put into perspective, as the machines were very maintenance-intensive and often suffered from engine problems, which led to high failure rates. In addition, a short time later the nationalists also had a bomber, the Italian Savoia Marchetti SM.79 , which was again faster than the Republican fighters. The slower Fiat CR.32 - Double Decker -Jägern nevertheless managed to achieve 48 confirmed kills of self by lying in wait for them at higher altitudes or cut off the road. At the latest when the then very modern Messerschmitt Bf 109 B and C were used by the Condor Legion , every advantage of the SB was gone. In the end, the machine did not come close to living up to expectations in this war. About 18 copies were captured by the Franquists after the civil war and flown with the Spanish Air Force until 1948 .

In the Second Sino-Japanese War from July 1937, the SB was reasonably successful because the Japanese fighters used were not the most modern or fastest. But even the bombing raids with the SB could not stop the Japanese advance in China. Again, the SB proved difficult to maintain and had a high number of failures.

Tupolev SB 2M-103, 38th SBAP, summer 1939

During the Japanese-Soviet border conflict in 1938/1939, the SB was used again, but this time it had a harder time against the newer Japanese fighters, so that the Soviets were ultimately forced to use escort fighters. The effectiveness of the SB in this brief conflict was ultimately not overwhelming for the Soviets, but it was still acceptable.

In the Soviet-Finnish winter war from 1939 to 1940, the SB of all versions was only moderately successful. The Finns succeeded in shooting down numerous machines of this type, not least because the Soviets initially completely lacked hunting protection. One of the first bombing raids on Helsinki turned into a disaster, as the Soviets were surprised by the stubborn resistance. A single Finnish pilot shot down four of these bombers over the capital within five minutes. The SB were used until the end of the hostilities, although losses continued to rise with the influx of more modern fighters to Finland.

Captured SB in Finnish service, October 1943

In the Second World War, the SB was already outdated and had practically no chance against the fighters of the German Air Force . It was therefore hardly possible to carry out missions with success, and of the machines that took off only a few returned to their airfields. However, the German troops captured numerous aircraft of this type on their advance. Some Avia B-71s were also taken over during the occupation of the ČSR in 1938 or continued to be built under German supervision, with the Air Force itself using some for a short time and others passing them on to the allies Bulgaria and Finland . In the Luftwaffe, all aircraft were called Avia B-71s, regardless of whether they were formerly Czech or Soviet aircraft.

In the Continuation War of Finland on the side of the German Reich from 1941, the SB played practically no role. In return, the Finns used the captured SB delivered by Germany against the Soviet Union. On the Soviet side, some of the 6656 units built remained in service at the front until 1943, when they were then moved to the rear lines for training and connection purposes.

Technical specifications

Three-sided view of ANT-40

Parameter	SB-2	SB-2bis	Ar-2
crew	3
length	12.27 m	12.57 m	12.50 m
span	20.33 m	20.33 m	18.50 m
height	4.78 m	3.25 m	4.20 m
Wing area	51.95 m²	56.70 m²	43.95 m²
Wing extension	8.0	7.3	7.8
Empty mass	4,060 kg	4,770 kg	4,430 kg
Takeoff mass	5,732 kg	7,880 kg	6,650 kg
drive	two liquid-cooled 12-cylinder V-engines M-100	two liquid-cooled 12-cylinder V-engines M-103	two liquid-cooled 12-cylinder V-engines M-105R
Starting power	750 PS (552 kW) each	960 PS (706 kW) each	1,000 PS (735 kW) each
Top speed	424 km / h at 4000 m	450 km / h	480 km / h at 4700 m
Summit height	9,500 m	7,800 m	10,100 m
Range	1,000 km	2,300 km	1,500 km
Armament	3 × 7.62 mm MG SchKAS	6 × 7.62 mm MG SchKAS	3 × 7.62 mm MG SchKAS
Bomb load	500 kg	600 kg	1,500 kg

Preserved copies

SB in the Monino Museum

Today a Tupolev SB from an early production series with the original engine covers is still in the Central Museum of the Air Force of the Russian Federation in Monino near Moscow . The poorly preserved wreckage of the aircraft was found in August 1979 by an expedition led by E. Konopljew on the bank of the Ukschum and rebuilt from August 1980 to mid-1982 by a special department of OKB Tupolev using original parts from other SB-2s. The Klimow M-100A of the SB-2, which has also been on display since 1982, is the only original engine of this series that still exists.

User states

•  Soviet Union : SB-2, SB-2bis (total 6656) and PS-40, PS-41 and PS-41bis; USB (SB-3)
•  Spain : 93 SB 2 M-100 or M-100A
•  Czechoslovakia : 53 SB 2 M-100A imported, 111 Avia B-71 manufactured under license
•  Finland : 24 SB-2 and SB-2bis
•  China : around 200 SB
•  German Empire : Avia B-71 and SB 2 M-100A captured by Czechoslovakia

See also

• List of aircraft types

literature

• Olaf Groehler : History of the Air War 1910 to 1980 . Military publishing house of the German Democratic Republic , Berlin 1981.
• Wilfried Copenhagen : Soviet bomb planes . Transpress, Berlin 1989, ISBN 3-344-00391-7 .
• Types of aircraft in the world . Models, technology, data. Bechtermünz, Augsburg 1997, ISBN 3-86047-593-2 , p. 880 (American English: The encyclopedia of world aircraft . Translated by Thema Produktmarketing und Werbung mbH, Munich).
• Lennart Andersson: Soviet Aircraft and Aviation 1917–1941. Putnam, London 1997, ISBN 0-85177-859-3 .

Web links

Commons : Tupolev SB (ANT-40)  - collection of pictures, videos and audio files

Individual evidence

1. ^ Olaf Groehler: History of the Air War 1910 to 1980 . Military Publishing House of the German Democratic Republic, Berlin 1981, p. 151 .
2. ↑ Архангельский СБ 2РЦ (АНТ-40). Retrieved December 25, 2019 (Russian). 
3. ↑ Архангельский СБ. Retrieved December 25, 2019 (Russian). 
4. ↑ ^{a b} types of aircraft in the world . Models, technology, data. Bechtermünz, Augsburg 1997, ISBN 3-86047-593-2 , p. 880 (American English: The encyclopedia of world aircraft . Translated by Thema Produktmarketing und Werbung mbH, Munich).
5. ↑ Aerosport 10/1968, p. 402
6. ^ Aircraft types - Archangelski SBB-1 . In: Fliegerrevue . No. 9 , 1981, pp. 430 .
7. ^ Riccardo Niccoli: Airplanes: The most important types of aircraft in the world . Kaiser, ISBN 3-7043-2188-5 , p. 206 .
8. ↑ ^{a b c} Aerosport No. 6/1966, p. 213
9. ↑ Flieger Revue 10/82, Umschau International, section aircraft construction, p. 442.
10. ↑ Flieger Revue 2/83, Umschau International, category exhibitions / museums, p. 58