Tupolev TB-3

https://en.wikipedia.org/wiki/Tupolev_TB-3

The Tupolev TB-3 (Russian: ??????? ??????????????, Tyazholy Bombardirovschik,
Heavy Bomber, civilian designation ANT-6) was a heavy bomber aircraft which was
deployed by the Soviet Air Force in the 1930s and during World War II. It was
the world's first cantilever wing four-engine heavy bomber. Despite obsolescence
and being officially withdrawn from service in 1939, the TB-3 performed bomber
and transport duties throughout much of World War II. The TB-3 also saw combat
as a Zveno project fighter mothership and as a light tank transport.

The TB-3 was an all-metal aircraft of steel construction, as one of the designs
from Andrei Tupolev's design bureau to be based on the 1918-onward all-metal
aircraft design practices and technology pioneered by Hugo Junkers. The frame
was composed of V-section beams covered with non-stressed corrugated skin
ranging from 0.3 mm (1/64 in) to 0.8 mm (1/32 in) in thickness. The corrugations
were 13 mm (0.51 in) deep and 50 mm (1.97 in) apart. The cantilever wing was
supported by four tube-section spars. In 1934, thanks to the development of
stronger steel alloys, the wingspan was increased from 39.5 to 41.85 metres
(129.6 to 137.3 ft) with a concurrent wing area increase from 230 to 234.5 m2
(2,476 to 2,524 sq ft). Any part of the aircraft could be walked on in soft
shoes without damaging the skin, and the leading edges of the wings swung down
to form walkways for engine maintenance. Controls were cable-actuated with a
variable-incidence tailplane and a trim compensation system in case of engine
failures on one side. Fixed main landing gear was not fitted with brakes. The
fuel tanks did not have fire or leak protection, although the engines had an
internal fire-extinguishing system. The M-17 engines were tuned to provide a
maximum theoretical range of 3,250 kilometres (1,750 nmi; 2,020 mi) without
spark plug or carburetor fouling. Defensive armament consisted of light machine
guns in five turrets — one in the nose, two on top of mid-fuselage, and one
retractable "dustbin" under each wing between the engine nacelles. Later
variants moved one of the top fuselage turrets aft of the tail fin.


Role
Heavy bomber

Manufacturer
Voronezh Aircraft Production Association

Designer
Andrei Tupolev

First flight
22 December 1930

Introduction
1932

Retired
1939 Soviet Air Force (officially)
1945 Soviet Air Force (de facto)

Primary users
Soviet Air Force
Aeroflot

Produced
1932–1934, 1935–1937

Number built
818

Developed from
Tupolev TB-1

Developed into
Tupolev ANT-16

The TB-3 was used operationally during the Battle of Khalkhin Gol against Japan
and in the Winter War with Finland. Although it was officially withdrawn from
service in 1939, at the start of the Great Patriotic War on 22 June 1941, the
Soviet Air Force had 516 operational TB-3s, with an additional 25 operated by
the Soviet Navy. Stationed far from the USSR's western border, the ?B-3s avoided
catastrophic losses during the first German air strikes, after which TB-3s from
3rd TBAP (Heavy Bomber Regiment) began flying night bombing missions on 23 June.
A shortage of combat-ready aircraft also required daytime use of TB-3s without
fighter escort and in this role the bombers, operating at low-to-medium
altitudes, suffered heavy losses to enemy fighters and ground fire. By August
1941, TB-3s made up 25% of the Soviet bomber force and, operated by elite air
force crews, were flying up to three combat missions per night. The aircraft
participated in all major battles through 1943, including the first Battle of
Smolensk, the Battle of Moscow, the Battle of Stalingrad, the Siege of
Leningrad, and the Battle of Kursk. On 1 July 1945, 18th Air Army still had ten
TB-3s on the active roster.

The TB-3 served extensively as a cargo and paratroop transport, carrying up to
35 soldiers in the latter role. In the first five months of the war, the
aircraft transported 2,797 tons of cargo and 2,300 personnel.

The TB-3 was also used in several special projects as a fighter mothership in
the Zveno project and for delivering light T-27, T-37, and T-38 tanks. On 1
August 1941, a pair of TB-3s in Zveno-SPB configuration, each with two
Polikarpov I-16 fighters carrying a pair of 250 kilograms (550 lb) bombs,
destroyed an oil depot with no losses in the port of Constan?a, Romania. On 11
August and 13 August 1941, Zveno-SPB successfully damaged the King Carol I
Bridge over the Danube in Romania. Zveno operations ended in the autumn of 1942
due to high vulnerability of the motherships.

In recognition of the role TB-3 played during the war, three aircraft were
included in the first post-war air parade on 18 June 1945.

Specifications (TB-3 4M-17F, 1934 model)

General characteristics
Crew: Eight - Ten
Length: 24.4 m (80 ft 1 in)
Wingspan: 41.80 m (137 ft 2 in)
Height: 8.50 m (27 ft 11 in)
Wing area: 234.5 m2 (2,524 ft2)
Empty weight: 11,200 kg (24,690 lb)
Loaded weight: 17,200 kg (37,920 lb)
Max. takeoff weight: 19,300 kg (42,550 lb)
Powerplant: 4 × Mikulin M-17F V12 engine, 525 kW (705 hp) each

Performance
Maximum speed: 212 km/h (114 knots, 129 mph) at 3,000 metres (9,800 ft)
Range: 2,000 km (1,080 NM, 1,240 mi)
Service ceiling: 4800 m (15,750 ft)
Rate of climb: 1.25 m/s (246 ft/min)
Wing loading: 73 kg/m² (15 lb/ft²)
Power/mass: 0.15 kW/kg (0.09 hp/lb)
Time to altitude: 4 min to 1,000 metres (3,300 ft), 22 min to 3,000 metres
(9,800 ft)
Best turn time: 40 seconds
Takeoff roll: 300 metres (980 ft)
Landing roll: 330 metres (1,080 ft)

Armament

Guns: 6–8× 7.62×54mmR DA machine guns, 100 63-round magazines
Bombs: Up to 5,000 kilograms (11,000 lb) of bombs standard load




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