Tupolev SB

Infobox Aircraft
name = ANT-40 / SB
type = Light bomber
manufacturer = Tupolev

---

caption = Finnish SB
designer = Alexander Arkhangelsky
first flight = 7 october 1934
introduced = 1936
retired = 1950 (Spanish Air Force)
status =
primary user = Soviet Air Forces
more users = Czechoslovakian Air Force
Chinese Nationalist Air Force
Luftwaffe
produced = 1936-1941
number built = 6,656
unit cost =
variants with their own articles = The Tupolev ANT-40, also known by its service name Tupolev SB ( _ru. Скоростной бомбардировщик - "Skorostnoi Bombardirovschik" - "high speed bomber"), and development co-name TsAGI-40, was a high speed twin-engined three-seat monoplane bomber, first flown in 1934.

The design was very advanced, but lacked refinement, much to the dismay of crews and maintenance personnel - and of Stalin, who pointed out that "there are no trivialities in aviation".

Numerically the most important bomber in the world in the late 1930s, the SB was the first modern stressed-skin aircraft produced in quantity in the Soviet Union and probably the most formidable bomber of the mid-1930s. Many versions saw extensive action in Spain, the Republic of China, Mongolia, Finland and at the beginning of the War against Germany in 1941. It was also used in various duties in civil variants, as trainers and in many secondary roles.

Successful in the Spanish Civil War because it outpaced most fighters, the aircraft was obsolete by 1941. By June, 1941, 94% of bombers in the Red Army air force (VVS RKKA) were SBs.

Development

In 1933 the Soviet Air Force ministry (UVVS) issued an outline requirement for a high-speed bomber. Work on this proposal at TsAGI began in January 1934. The SB was designed and developed in the Tupolev KB ("Design Bureau") by a team led by A. A. Arkhangelski. Two versions were planned - with Wright Cyclone engines, and with the Hispano-Suiza 12Y. The skills gained in the design of the MI-3 and DI-8 aircraft were widely used. The first two prototypes were designed as ANT-40.1 and ANT-40.2.

ANT-40.2 was considered a production prototype, and its performance was impressive. The production aircraft designation was SB, and the first SB rolled off the production line before the end of 1935, and before ANT-40.2 had completed its flight test programme. The aircraft entered full production in 1936, and was produced in two plants until 1941.

Despite the fact that the assembly lines were plagued with a constant string of modifications, some 400 SBs were delivered by the end of 1936 - a number of these being diverted to Spain - and 24 VVS squadrons were in the process of working up with the new bomber. Giving excellent performance in the Spanish Civil War, it acquired the popular name "Katyushka".

In 1937 negotiations were successfully concluded between the Soviet and Czechoslovak governments. The version of the SB to be supplied to, and subsequently license-built in, Czechoslovakia was fundamentally the SB-2M-100A and, as the Avia B-71, was to be fitted with the Avia-built Hispano-Suiza 12-Ydrs engine. A single 7.92mm ZB-30 machine gun supplanted the twin ShKAS machine guns in the nose and similar weapons were provided for the dorsal and ventral stations.

Sixty aircraft were to be flown to Czechoslovakia by mid-1938. The planned licensed production program took a decidedly leisurely course, despite the increasingly dangerous political situation. By 15 March 1939, when the German Wehrmacht occupied Bohemia and Moravia, not one Czech-built aircraft had been delivered.

Design

The SB was an all-metal monoplane powered by two Klimov M-100 12-cylinder water-cooled engines (license production version of Hispano-Suiza 12-Yrds engine) which drove fixed-pitch two-bladed metal propellers. The engines were provided with honeycomb-type frontal radiators enclosed by vertical thermostat-controlled cooling shutters. At an early production stage, the M-100 engine gave place to an improved M-100A engine, driving ground-adjustable three-pitch propellers, with speed being boosted to 423 km/h (264 mph) at 4,000 meters (13,100 ft).

Variants

* ANT-38 - prototype with radial engines (Possibly the ANT-40.1)
* ANT-39 - (related?)
* ANT-40.1 or ANT-40 2RTs - the first variant with 545 kW (730 hp) Wright-Cyclone engines built in October 1934. Smaller than most of the later SBs. Test flights by I.S. Zhurov and K.K. Popov from 7-31 October 1934 ended in a crash landing. The aircraft was repaired by February 1935 and a second set of test flights were made 5 February 1935 to 31 July 1935. Used as experimental (ski gears, etc). model.
* ANT-40.2 or ANT-40 2IS - built in late 1934. Preliminary test flights in January 1935 gave a speed of 430 km/h (269 mph). More test flights from February 1935 to April 1936. Then given to the production plant as a standard.
* SB-2M-100 - first production model. Wing area increased to 56.7 m² (610 ft²). Equipped with Klimov M-100 engines (the Hispano-Suiza 12Y built under licence). Sometimes unofficially referred to simply as the SB.
* DI-8/ANT-46 - two-seat heavy fighter modification equipped with the 800 hp Gnome-Rhône 14K engines and armed with two recoilless 100mm cannon. 1935.
* SB-2M-100A - new engines of 642 kW (860 hp). Modified engine covers. Produced from late 1936. Sometimes unofficially referred to as the SBbis
* SB-2M-100A Modernized - new rear gun installation "Tur" MV-3. Tested in 1937. Accepted, but no production.
* SB-2M-103/SBbis - new engines, bigger navigator cockpit, new controllable rear wheel. First tested in September 1937. Further tests from 27 June 1938 to 19 September 1938. Starting with this version the SB-2 had retractable ski gears. On 2 September 1937 M.Yu. Alexeev set an official altitude record of 40,169 ft (12,244 m) with load of 1,000 kg (2,200 lb). On 1 November 1936 he had set an unofficial record of 41,639 ft or 12,692 m. Sometimes referred to as the SB-3.
* PS-40 2M-100A - cargo version for Aeroflot in 1938.
* USB - trainer, tested in 1938. The navigator was replaced by the instructor. Only produced in small numbers.
* SBbis2-2M-103 - with polished wings. No production.
* SBbis3-2M-103 - new propeller and engine. Tested from 1 November 1937 to 17 January 1938. Significant increase in speed. Few were built.
* SB-2M103-1939 - production model development of the SBbis3. New radiators and partially polished wings. Propeller: VISh-2, then VISh-22. Tested in September-October 1939. New gunner's cockpit and guns from 1940.
* PS-41-2M103U - an old SBbis3 "written off" to Aeroflot for civil use.
* PS-41bis-2M-103U - mail carrier. PS-41 with additional external fuel tanks. 180 kg (396 lb) cargo load.
* MMN-2M-105 - new engines, reduced wing area, 3x ShKAS machine guns only. Tested in 1939 and rejected. Used as an experimental model for the SB-RK.
* SB-RK - Dive bomber, also known as the RK, KR or Ar-2. Two Klimov M-105R engines with VISh-22E props. Wing area reduced as for MMN. The cooling radiators were buried within the wings, with an air intake on the leading and the exhaust on the wing's upper surface. Equipped with four ShKAS machine guns, and it could carry a bomb payload of 6 x 100 kg (220 lb), 2 x 250 kg (550 lb), 1 x 500 kg (1,100 lb), VAP-500, ZAP-500 and others internally, plus up to 1,500 kg (3,300 lb) externally. This was the final model of the SB-2. Few were built before it was superseded by the Pe-2 and Tu-2.
* 3-wheel SB - experimental TsAGI model. Tested by M.L. Gallay. 1940-1941.
* T-1/ANT-41 - torpedo bomber modification.

Operators

;flag|Bulgaria|1878
*Bulgarian Air Force operated 32 Avia B-71 aircraft redesignated Avia-Katiusza Ě-8.;China as ROC
*Chinese Nationalist Air Force received 62 SB-2M-100 bombers in the autumn 1937. The Soviet Union delivered more SB-2M-100 and SB-2M-105 bombers between August 1938 and June 1941.;CZS
*Czechoslovakian Air Force received 60 Russian-built SB with Hispano Suiza 12Ybrs engines in April and May 1938. Another 101 bombers and 60 reconnaissance aircraft were license-built Avia B-71 but only 101 were built.;FIN
*Finnish Air Force operated 24 SB bombers. The first eight aircraft (seven powered by M-103 engines, one by M-100 engines) were captured during the Winter War, another 16 aircraft were converted from captured German materiel between 5 November 1941 and 27 August 1942. All aircraft were refitted with M-103 engines and were used as anti-submarine aircraft in the LeLv 6 squadron. Two aircraft were rebuilt and were used as trainers. The Finnish Air Force withdrew all SB aircraft in 1945, and all were scrapped in 1950.;flag|Germany|Nazi
*Luftwaffe operated captured aircraft, Czech-built Avia B-71 and Soviet SB.;POL
*Polish Air Force operated few USB-2M-103 aircraft for training after World War II.;flagicon|Slovakia|1938 Slovakia
*Slovak Air Force operated one Avia B-71 aircraft until August 1944.;USSR
*Soviet Air Force
*Aeroflot received an unknown number of retired military SB-2M-100 aircraft in 1938 and after rebuild, used them under the designation PS-40. Another batch of retired SB bis 3 bombers was rebuilt in 1940 and used under the designation PS-41.;flagicon|Spain|1931 Spanish Republic
*Republican Spanish Air Force received its first 31 SB-2M-100A bombers on 14 October 1936. The second batch of 31 aircraft was delivered in June 1937. The Soviet Union delivered about 70 aircraft total.;flagicon|Spain|1939 Spanish State
*Nationalist Spanish Air Force captured 19 SB-2M-100A bombers. All were overhauled and Soviet M-100 engines were replaced with French Hispano Suiza 12Ybrs. These aircraft were used operationally and later for training duties, and were retired in 1950. Spanish pilots called captured SB bombers "Sofia".

pecifications (SB)

aircraft specifications
plane or copter?=plane
jet or prop?=prop
ref=
crew=three
capacity=
payload main=
payload alt=
length main= 12.57 m
length alt= 41 ft 3 in
span main= 20.33 m
span alt= 66 ft 8 in
height main= 3.48 m
height alt= 11 ft 5 in
area main= 56.0 m²
area alt= 602 ft²
airfoil=
empty weight main= 4,768 kg
empty weight alt= 10,512 lb
loaded weight main= 7,880 kg
loaded weight alt= 17,370 lb
useful load main=
useful load alt=
max takeoff weight main=
max takeoff weight alt=
more general=
engine (prop)= Klimov M-103
type of prop=
number of props=2
power main= 716 kW
power alt= 960 hp
power original=
max speed main=450 km/h
max speed alt= 280 mph
cruise speed main=
cruise speed alt=
stall speed main=
stall speed alt=
never exceed speed main=
never exceed speed alt=
range main= 2,300 km
range alt=1,430 miles
ceiling main= 7,800 m
ceiling alt= 25,600 ft
climb rate main= 570 m/min
climb rate alt= 1,870 ft/min
loading main=141 kg/m²
loading alt=29 lb/ft²
thrust/weight=
power/mass main=0.18 kW/kg
power/mass alt=0.11 hp/lb
more performance=
armament=
* 6 × 7.62 mm ShKAS machine guns
* 600 kg (1,320 lb) of bombs
avionics=

References

* Kulikov, Victor and Michulec, Robert."Tupolew SB, Monografie Lotnicze 83". Gdańsk, AJ-Press, 2002. ISBN 83-7237-113-X (Polish publication).
* MPM (Modely Plastikvym Modelarum) manual to SB-2M-100 model kit
* http://www.aviation.ru/Tu/#ANT-40

ee also

aircontent
related=
Tupolev ANT-38 -
Tupolev ANT-41 -
Arkhangelski Ar-2
similar aircraft=
Bristol Blenheim
sequence=
ANT-35 -
ANT-37 -
ANT-38 -ANT-40 -
ANT-41 -
ANT-42 -
ANT-44
lists=
see also=