Skorostnoi Bombardirovshik SB

On October 1936 the Republican Spanish Air Force received an infusion of about 50 Russian aircraft. SB[SD-2] Katuska bombers began operations before the month was out.

The well known workhorse of the Spanish Civil War and 1939-40 Russo-Finnish “Talvisota” (winter-war),  the Tupolev SB, which certainly fits the stated engine and armament criteria you proposed. The SB was obsolete by the outbreak of Barbarossa in June 1941, and many were shot-up on the ground by the Luftwaffe during the first hours and days of the attack. However, enough survived until at least early 1942 to have been employed as night attack aircraft, which was in fact, the only role they were actually suited for because of their vulnerability to German day fighters. In this role, the remaining SB’s reportedly did well, until phased into rear-area transport and target-tug duties.

The SB was driven by twin 850-horsepower M100 V-12 piston engines to a top speed of 255 miles per hour and a service ceiling of 27,885 feet. Its range was a modest 746 miles. Wingspan was 66 feet 8 ½ inches, and defensive armament consisted of two 0.3-inch machine guns in a nose turret, one in a dorsal turret, and one in the ventral position. Bomb capacity was 2,205 pounds, and the plane was crewed by three.

The two ANT-40 light bomber prototypes of Andrei N. Tupolev’s design bureau were years ahead of their time when they first flew in October 1934: the all-metal construction, enclosed cockpit and retractable landing gear were then comparatively novel features. Indeed the ANT-40’s maximum speed of 325 km/h (202 mph) at operating height was faster than the biplane interceptor fighters that equipped most of the peacetime air forces. The initial production version as selected for export and service with the VVS was based on the second prototype, and was known as the Tupolev SB (skorostnoi bombardirovshchik, or fast bomber); the engines were two 830-hp (619-kW) licence-built Hispano-Suiza 12Ybr engines, termed M-100 by Soviet industry, and initially these were fitted with two-bladed fixed pitch propellers. The first SBs were passed to the VVS’s bomber aviation regiments in February 1936, and in October of that year the first of 210 were transferred with Soviet crews to Spain to fight on the side of the Republican air force against the insurgent Nationalists.

The theory that fast, well-armed bombers would survive (particularly if flying in tight formations protected by interlocking fire from their machine- guns) held water at first – but only because the fighters of 1936 lacked the speed to reach them and the, armament to do serious damage. For example, a Russian Tupolev SB [SB-2] twin-engine monoplane with a speed of 255 mph was a difficult target to intercept by an Italian biplane Fiat CR32 with a top speed of 233 mph – although on occasion this feat was performed. Evidence of this sort underlined the widespread opinion of those, such as the British Prime Minister Stanley Baldwin, that `the bomber will always get through’. It was assumed that this technical imbalance would persist and that, in any case, fighter actions would be impossible if their speeds increased much beyond the extant 220-mph mark. A natural reaction was to build bigger, faster and heavily-defended bombers in the pious hope that their existence would deter an aggressor from using his bombers – in much the same way as it was hoped that the possession of gas would deter its use.

Familiarly called the Katyusha, the Tupolev SB was first flown on October 7, 1933. Intended as a high-speed bomber, it was at the time one of the Tupolev organization’s most advanced designs, based on a heavy fighter airframe rather than a bomber. Construction was all metal and, in service during the Spanish civil war, its 255-mile-per-hour speed outflew many enemy fighters-until the appearance of the German Bf- 109 fighter. A total of 6,656 SBs were built up to 1940, and some remained in service until 1943, despite heavy losses to the Bf-109s.

Fast-flying SBs were among the world’s best bombers when they appeared in 1936. They enjoyed a distinguished career in Spain, Mongolia, and Finland before suffering heavy losses in World War II.

In 1933 the Soviet government announced specifications for an entirely new light bomber, one so fast that it could operate without escort fighters. The Tupolev design bureau finessed the problem with great skill, and in 1934 it built two prototypes with radial and in-line engines respectively. The new SB was Russia’s first stressed-skin aircraft, a midwing, all-metal monoplane bomber. It was modern in every respect to Western contemporaries and possessed such advanced features as retractable landing gear and flush-riveting. A crew of four was comfortably housed, and the plane flew faster than any fighter or bomber then in service, including the highly touted Bristol Blenheim. In 1936 the in-line engine prototype entered production as the SB, and nearly 7,000 were produced. These modern, capable craft formed the bulk of Soviet tactical aviation over the next five years and played a major role in modernizing and revitalizing the Soviet bomber forces.

SBs were bloodied in the Spanish Civil War (1936-1939), where they proved impervious to slower Nationalist fighters. They also enjoyed similar success in Mongolia against the Japanese and were exported to China in quantity. Several new versions were also introduced with more powerful engines, but this robust design was growing obsolete in light of developments elsewhere. SBs again fought well against Finland during 1939-1940, but when Germany invaded Russia the following year they lost their speed advantage. The SB’s record as a day bomber came to an abrupt end during the fierce fighting following the German invasion of the USSR on 22 June 1941. Those that were not destroyed on the ground ventured into the air on numerous and gallantly-flown missions over the front line and paid a heavy price to the Luftwaffe’s Messerschmitt Bf 109F fighters. Thereafter the SB and SBbis bombers were relegated to night work with the VVS and the Soviet naval air arm. They did so in a wide variety of roles, including that of night intruder and torpedo-bomber. By the time SBs withdrew in 1943, they had sustained the heaviest losses of any Russian aircraft in World War II. Production amounted to 6,967 of all marks.

Specifications (SB 2M-103)

General characteristics

Crew: 3

Length: 12.57 m (41 ft 2¾ in)

Wingspan: 20.33 m (66 ft 8 in)

Height: 3.60 m (11 ft 9¾ in)

Wing area: 56.7 m² (610.3 ft2)

Empty weight: 4,768 kg (10,512 lb)

Loaded weight: 6,308 kg (14,065 lb)

Max. takeoff weight: 7,880 kg (17,370 lb)

Powerplant: 2 × Klimov M-103 liquid-cooled V12 engine, 716 kW (960 hp) each

Performance

Maximum speed: 450 km/h (243 knots, 280 mph) at 4,100 m (13,450 ft)

Range: 2,300 km (1,243 nmi, 1,429 mi)

Service ceiling: 9,300 m (30,510 ft)

Climb to 1,000 m (3,280 ft): 1.8 min

Climb to 9,000 m (29,500 ft): 32 min

Armament

Guns: 4 × 7.62 mm ShKAS machine guns (two in nose, one in dorsal and one in ventral position)

Bombs: 6 × 100 kg (220 lb) or six 50 kg (110 lb) bombs in bomb-bay, 2 × 250 kg (550 lb) bombs on wing racks

Note

Index SB of Arkhangelsky’s high-velocity bomber comes from plain meaning:

“Skorostnoi Bombardirovshik”.

skorostnOi = high velocity

bombardirOvshik = bomber

Actual index must be like below

SB 2RTs

SB 2IS

SB 2M-100

SB 2M-100A

SB 2M-103

etc.

the index reads “SB with TWO engines <namely>”.

I don’t know why west took TWO as a part of plane’s name.

It is not SECOND bomber or SECOND design.

All articles related to the Tupolev SB still carry the misnomer of SB-2 [including this one for familiarity]. It may well be that the Germans started this incorrect nomenclature.

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