Tupolev TB-3

The Red Army Air Force under the command of Yakov Alksnis during 1931–1937 developed into a semi-independent military service with a combat potential, good training, and a logistics infrastructure spreading from European Russia into Central Asia and the Far East. Still, the Red Army Air Force exhibited marked deficiencies in several local conflicts (e. g., against the Chinese in 1929 and in the Spanish civil war, 1936–1939). In contrast, during the 1937–1939 air conflicts with Japan (China, Lake Khasan, Khalkin Gol) the Soviets effectively challenged the Japanese air domination and provided decisive close air support in the campaigns on Soviet and Mongolian borders. During the Winter War with Finland (1939–1940), however, the Red Air Force suffered heavy losses due to inflexibility of organization, its command-and-control structure, poor training of personnel, and deficiency of equipment.

He sponsored the introduction of the truly remarkable Tupolev TB-3, the world’s first four-engine monoplane bomber in squadron service. Although a force of several hundred aircraft was built up, it was not intended as a classical strategic bombing force in the manner advocated by Douhet, who actually had little influence on Soviet thinking. Alksnis simply saw the need for heavy bombers to complement the other Soviet forces. He was, unfortunately, a friend of Tukachevski, and was arrested on a false charge of treason in December 1937 but not executed until 1940.

In June 1941 almost all Soviet bombers were of two totally different designs by A. N. Tupolev. One was the monster TB-3, which in 1930 was by far the greatest and most formidable bomber in the world. The last of the 819 built came off the line in 1938. The TB-3 was a major type in the Winter War, and nearly all survivors were still in service when Hitler invaded, but by 1941 these noble aircraft – despite repeated updates and numerous interesting armament fits – were no longer modern enough for combat duty. Instead they performed prodigious feats as transports.

At the very beginning of serial production the American engine was replaced by a German-built BMW-VI and then by the M-17F, the Soviet copy of the German engine. In late 1931 a new engine, designated M-34 and rated at 750 to 830hp (559 to 619kW), passed all of its tests and went into serial production. In January 1933 the drawings for replacement of the M- 17Fs with the M-34 were ready, and on 8th March the ANT-6 made its first flight with the new powerplant. Unfortunately it suffered an accident and was heavily damaged. It was not until the autumn that the second prototype was moved to the Air Force Scientific Research Institute for flight testing. This aircraft passed all the tests without any trouble, and showed its superiority over the earlier M-17Fengined version in speed, payload capacity, stability and controllability, as well as in its take-off and landing performance. When the modified M-34 with an increased compression ratio, designated M-34R, and the M-34RN with an even greater compression ratio and supercharging (the power increased to 840 to 970hp – 626 to 723kW) were put into production, all of the TB-3’s flying characteristics were significantly improved.

The flypast of the first nine new production bombers over Red Square during the May Day celebration caused a sensation and puzzled Western air force attaches.

Changing the powerplant was not the only way to improve the aircraft. In 1933 the spring shock absorbers of the undercarriage were replaced by oleo-pneumatic shock examples, enhancing safety during take-off and landing. In 1935 the corrugated surface was replaced by a smooth skin, and tests of this modification showed much better flying characteristics. The first serial production bombers had a maximum speed of about 112mph (180km/h) and a service ceiling of 12,500ft (3,800m). Installation of the new powerplant increased maximum speed to 179mph (288km/h) and service ceiling to more than 12,500ft (3,800m). With its new engines the bomber could carry four tonnes of bombs, and the maximum range with a two-tonne bomb load increased to 1,553 miles (2,500km). Defensive armament comprised a single or twin TUR-6 gun turret with 7.62mm calibre DA machine guns, movable TUR-5 turrets installed immediately aft of the wing and housing one or two DA machine guns, and a dorsal turret with one DA machine gun.

The bombers with M-34R and M-34RN engines differed from the first production TB-3s in the design of their engine cowlings, and the M-34FRN also had a fully glazed cockpit canopy. The two inboard engines of aircraft powered by M-34RNs were installed closer to the fuselage and had four-blade propellers, while the two outboard engines had two-blade propellers. Three-blade propellers were installed on M-34FRN engines.

A large number of heavy bombers were needed to equip the Soviet Army Air Force’s newly-created long range bomber force. Only one factory was producing the TB-3, and it could not meet demands. Peotr Baranov, head of Aaviaprom, issued an order for TB-3 production to begin at a second plant which was then busy producing smaller aircraft. Andrei Tupolev appointed Joseph Nezval, a very experienced designer, consultant and director for the introduction of new technologies at the chosen plant.

Many difficulties were encountered, and as a result the products suffered from a mass of production defects. Nevertheless, work continued and progress was made in spite of the problems. The first aircraft rolled out of this factory was flown by Yulian Piontkovsky, and most of the production bombers were tested by Valery Chkalov.

From 1932 to 1939 the factories manufactured 818 TB-3s of different variants for a number of roles. In addition, under the designation G-l and G-2 the type was also used in civil aviation as a long range heavy cargo carrier to transport bulky loads to Siberia and the Far East. Using specially modified aircraft, personnel and equipment were delivered right to the North Pole, and on some flights landings were made on drifting ice. Some of the most skilled Russian pilots; Mikhail Vodopyanov, Vasily Molokov, Anatoly Alexeev, Ilya Mazuruk and Mikhail Babushkin, took part in these historic flights.

Large numbers of TB-3s served with the air force. A bomber with big bomb load and strong defensive armament was a significant force in mid-1930s and the very existence of the TB-3 served to restrain Japanese militarism on the USSR’s eastern borders. The TB-3 was used in real combat conditions for the first time in the late 1930s. In the summer of 1938, 60 TB-3s, flying in large formations, attacked Japanese ground forces in the region of Hasan Lake. The same tactic was used in the spring of 1939, during the Japanese invasion in Khalkhin-Gol. In January 1940 the TB-3s bombed Finnish troops on the Karelia peninsula.

Under direction of the Headquarters of the Supreme Commander-in-Chief, during six days in August 1941 TB-3s repeatedly attacked the German tank columns in the Starodub, Trubachevsk and Unech regions.

In the late 1930s the speed of fighters grew considerably, so the demands placed upon bombers also had to change. At the very beginning of the Second World War it became obvious that Soviet long-range aviation force must be equipped with new types of aeroplanes. The TB-3 was used as a heavy bomber only in the first year of war. As the fighter units had suffered heavy losses, the bombers flew their missions without escorts, and mainly at night.

It was still not really safe to use the aircraft for bombing, so in an attempt to avoid heavy losses the command decided to use it only as a transport to drop cargo by parachute. The TB-3 had been evaluated in this role before the war. In the Kiev Military District in September 1935, large scale manoeuvres by different Soviet Army arms took place. During these manoeuvres, for the first time in Soviet military history, a mass airborne invasion force including 1,188 paratroopers was used. In an operation lasting only 110 minutes, heavy aircraft delivered 1,975 soldiers, one T-37 tank, six trucks and ten artillery pieces on to a ‘captured enemy airfield’. To transport bulky loads the TB-3 was fitted with a special suspended frame, and it could also accommodate 35 soldiers with ammunition or 30 equipped paratroopers.

In the autumn of 1941, having an advantage over the Soviet Army in combat capable troops and weapons, the Germans opened an offensive in the direction of Moscow. There was a threat that German troops attacking from the south would take Moscow and also capture the Soviet 3rd and 13th Armies, and ground forces in the Orel area required urgent reinforcement.

The Soviet command decided to transport the 5th Air Assault Corps to the region, and 6,000 personnel along with ammunition, armament, trucks and guns were delivered there by air in three days. Two-thirds of the 60 aeroplanes which participated in this operation were TB-3s, and all of the flights were made in daytime without fighter escort. No losses were reported during the operation.

From 18th to 22nd January 1942 TB-3s participated in an operation in which two battalions of the 201st Airborne Brigade and the 250th Airborne Regiment were delivered to the region south of Vyazma. In late September 1942 an airborne force of many thousands was landed at the Bukrinsk foreland by order of Georgy Zhukov, to support units that had crossed the Dnepr. The 53rd Air Division, commanded by Col I Georgiev and equipped with TB-3s, took part.

Variants

TB-3 4M-17F

    The first production version, comprised about half of all TB-3s built.

TB-3 4M-34

    Mikulin AM-34 engines with revised radiators, added oil coolers, several dozen built.

TB-3 4M-34R

    Mikulin AM-34R engines with reduction gearboxes providing significantly improved performance, additional turret aft of the tail fin, tail wheels with hydraulic brakes, aerodynamic refinements of the wing-fuselage join and radiators, retractable wind generators.

TB-3 4AM-34RD

    A series of long-range demonstration aircraft with streamlined fuselages and wheel brakes. Some aircraft had single main gear wheels 2 metres (6.6 ft) in diameter and three-blade metal propellers. Used for flights to Warsaw, Paris, and Rome in 1933–1934.

TB-3 4AM-34RN

    High-altitude version with AM-34RN engines, four-blade propellers on inboard engines and two-blade on outboard, 2 metres (6.6 ft) single main wheels, turrets upgraded to ShKAS machine guns, top speed 288 kilometres per hour (156 kn; 179 mph) at 4,200 metres (13,800 ft), service ceiling 7,740 metres (25,390 ft). Tested in August–October 1935 but did not enter production as the basic TB-3 design was becoming obsolete.

TB-3 4AM-34FRN/FRNV

    AM-34FRN/FRNV engines with increased power output and four-blade propellers, aerodynamic refinements including streamlined turrets, 2 metres (6.6 ft) main wheels with brakes, top speed over 300 kilometres per hour (160 kn; 190 mph).

TB-3D

    Proposed variant with Charomsky AN-1 diesel engines of 750 PS (740 hp) and projected range of 4,280 km (2,310 nm, 2,660 mi), did not enter production as other performance characteristics were inferior to TB-3 4AM-34RN.

G-2

    Retired TB-3s with M-17 and M-34 engines converted for freight duties with Aeroflot

ANT-6-4M-34R “Aviaarktika”

    TB-3 modified for the 1937 expedition to the North Pole with enclosed cockpit, single 2 metres (6.6 ft) main wheels, three-blade metal propellers.

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

General characteristics

    Crew: 8-10

    Length: 24.4 m (80 ft 1 in)

    Wingspan: 41.8 m (137 ft 2 in)

    Height: 8.5 m (27 ft 11 in)

    Wing area: 234.5 m2 (2,524 sq ft)

    Airfoil: Tupolev A0 (20%) ; tip: Tupolev A0 (10%)[17]

    Empty weight: 11,200 kg (24,692 lb)

    Gross weight: 17,200 kg (37,920 lb)

    Max takeoff weight: 19,300 kg (42,549 lb)

    Powerplant: 4 × Mikulin M-17F V-12 liquid-cooled piston engines 715 PS (705 hp; 526 kW)

    Propellers: 2-bladed fixed-pitch propellers

Performance

    Maximum speed: 212 km/h (132 mph, 114 kn)

    Range: 2,000 km (1,200 mi, 1,100 nmi)

    Service ceiling: 4,800 m (15,700 ft)

    Rate of climb: 1.25 m/s (246 ft/min)

    Time to altitude: 1,000 m (3,281 ft) in 4 minutes

                                   3,000 m (9,843 ft) in 22 minutes

    Wing loading: 73 kg/m2 (15 lb/sq ft)

    Power/mass: 0.15 kW/kg (0.091 hp/lb)

    Take-off run: 300 m (984 ft)

    Landing run: 330 m (1,083 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

ZVENO

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