Overview

The Tupolev Tu-4 (NATO reporting name: "Bull") was the Soviet Union's first strategic heavy bomber, essentially a reverse-engineered copy of the American Boeing B-29 Superfortress. Entering service in 1949, it provided the USSR with intercontinental bombing capability and served as the delivery platform for the first Soviet atomic weapons. The Tu-4 remained operational until the early 1960s, bridging the gap until indigenous jet bombers like the Tu-16 became available.

Historical context

In 1944, three U.S. B-29 bombers made emergency landings in Soviet territory after missions over Japan. Despite American requests for their return (the USSR was neutral toward Japan at the time), Stalin ordered Andrei Tupolev to reverse-engineer the aircraft within two years. Soviet engineers meticulously disassembled the B-29s, creating over 105,000 drawings and converting Imperial measurements to metric standards while maintaining structural integrity.

The first Tu-4 prototype flew in May 1947, with serial production beginning in 1948 at factories in Kazan and Kuibyshev. By 1949, a public fly-past of multiple Tu-4s shocked Western observers who had underestimated Soviet reverse-engineering capability. The aircraft became operational just in time for the Soviet nuclear program, dropping the first Soviet atomic bomb during tests at Semipalatinsk in 1951.

Specifications

Commonly cited specifications (Tu-4 baseline):

Dimensions:

  • Length: 30.18 m (99 ft)
  • Wingspan: 43.05 m (141 ft 3 in)
  • Height: 8.46 m (27 ft 9 in)
  • Wing area: 161.7 m² (1,740 sq ft)

Weights:

  • Empty weight: 32,270 kg (71,120 lb)
  • Normal loaded: 47,500 kg (104,719 lb)
  • Maximum takeoff: 66,000 kg (145,505 lb)

Powerplant:

  • Engines: 4 × Shvetsov ASh-73TK 18-cylinder radial piston engines
  • Power: 2,400 hp (1,790 kW) each at takeoff
  • Supercharging: Two-stage mechanically driven + turbosupercharger

Performance:

  • Maximum speed: 558 km/h (347 mph, 301 kn) at 10,250 m
  • Cruising speed: 400 km/h (249 mph)
  • Combat radius: 2,700 km (1,678 mi) with 3,000 kg bomb load
  • Ferry range: 6,200 km (3,852 mi) maximum
  • Service ceiling: 11,200 m (36,745 ft)
  • Rate of climb: 4.7 m/s (925 ft/min)
  • Wing loading: 294 kg/m² (60 lb/sq ft)

Armament:

Defensive guns: 10 × 23 mm Nudelman-Rikhter NS-23 cannons

  • Turrets: 2 × dorsal, 2 × ventral, 1 × tail (twin guns each)
  • Total ammunition: 6,000 rounds

Bomb load:

  • Normal: 6,000 kg (13,228 lb) internal
  • Maximum overload: 8,000 kg (17,637 lb)
  • Nuclear: 1 × RDS-3 atomic bomb (up to 42 kt yield)

Crew:

  • Complement: 11 (pilot, copilot, navigator, bombardier, flight engineer, radio operator, 5 gunners)

Design characteristics

Airframe

The Tu-4 copied the B-29's distinctive features:

Pressurized compartments: Forward (cockpit, bombardier) and rear (gunners) cabins connected by crawlway over bomb bays

High aspect ratio wings: Long, narrow planform optimized for high-altitude efficiency

Retractable tricycle landing gear: Main gear housed in nacelles, nose wheel forward

Dual bomb bays: Two compartments with roller-type doors, accommodating various ordnance configurations

Soviet modifications

While superficially identical to the B-29, Soviet engineers made numerous changes:

ASh-73TK engines: Shvetsov radials replacing Wright R-3350s, slightly less powerful but using available Soviet metallurgy

NS-23 cannons: 23 mm high-velocity guns instead of .50 caliber machine guns, providing superior hitting power

Metric fasteners: All fittings converted to Soviet standards

Radio equipment: Soviet-designed avionics replacing American sets

Structural reinforcement: Heavier gauge metal in critical areas to compensate for inferior Soviet aluminum alloys

These changes increased empty weight by approximately 3,000 kg versus the original B-29.

Defensive systems

Remote-controlled turrets: Gunners operated turrets via computerized fire control system (copied from B-29's General Electric system)

Sighting stations: Periscopic sights with lead-computing capability

Tail turret: Manually operated by dedicated gunner with independent fire control

Armor protection: Limited crew armor and self-sealing fuel tanks

Variants and developments

Operational variants

Tu-4 (baseline): Standard strategic bomber (1948-1953 production)

Tu-4A: Nuclear-capable variant with RDS-3/RDS-4 atomic bomb shackles, upgraded electrical systems (1952+)

Tu-4R: Photographic reconnaissance with camera suite replacing bomb bay equipment

Tu-4T: Torpedo bomber for Soviet Naval Aviation, could carry 2 × 45-36-AN torpedoes

Tu-4D: Long-range paratroop transport with passenger seating and jump doors

Tu-4LL: Engine testbed for early Soviet jet engines (Lyulka TR-1, Mikulin AM-3)

Experimental developments

Tu-80: Stretched fuselage variant with increased range (prototype only, 1949)

Tu-85: Deep redesign with more powerful ASh-82FN engines, 8,000 km range (3 prototypes, 1951-1952, cancelled in favor of jet bombers)

Tu-4K (KS-1 carrier): Anti-shipping platform carrying 2 × KS-1 "Komet" cruise missiles under wings (1950s conversion)

Operational deployment

Service timeline

  • 1947: First Tu-4 prototype flight (May 19)
  • 1948-1949: Initial production and crew training
  • 1949: Public debut at Tushino Aviation Day (August), operational deployment begins
  • 1951: First Soviet atomic bomb drop from Tu-4A at Semipalatinsk test site
  • 1952-1953: Peak deployment (~300 aircraft operational)
  • 1954-1956: Gradual replacement by Tu-16 jet bombers begins
  • 1960s: Retirement from bomber role, continued use as transports and testbeds
  • 1963: Final Tu-4 variants withdrawn from Soviet service

Operational units

Long-Range Aviation (Дальня Авиация): Primary operator, equipped strategic bomber regiments

Naval Aviation: Tu-4T torpedo bombers for anti-shipping missions

Transport Aviation: Tu-4D conversions for paratroop/cargo duties

The Tu-4 never saw combat, serving purely as a strategic deterrent during the early Cold War.

Strategic significance

Nuclear deterrent

The Tu-4A provided the USSR's only strategic nuclear delivery capability from 1951-1955. While vulnerable to NATO jet interceptors and unable to reach most U.S. targets from Soviet bases, it could threaten:

  • Western Europe from Soviet territory
  • Alaska and northern Canada from Arctic staging bases
  • U.S. bases in Japan and Guam
  • NATO installations in Turkey and Middle East

Technology transfer

Reverse-engineering the B-29 accelerated Soviet aviation technology by 5-10 years:

Pressurization systems: Enabled high-altitude passenger aircraft (Tu-104, Il-18)

Remote turret control: Influenced later bomber defensive systems

Heavy bomber construction: Techniques applied to Tu-16, Tu-95, Tu-22 designs

Fire control computers: Analog computing technology adapted for other applications

Engine development: ASh-73TK experience contributed to improved radials

Limitations

Obsolescence upon entry: By 1949, jet fighters like the F-86 Sabre and MiG-15 rendered propeller-driven bombers vulnerable

Range constraints: 2,700 km combat radius insufficient for intercontinental missions without forward staging bases

Speed: 558 km/h maximum speed made Tu-4 easy prey for contemporary jets

Maintenance intensity: 11-man crew and four complex engines created logistics burden

Engine reliability: ASh-73TK turbosuperchargers prone to failure, requiring frequent overhauls

Comparison with contemporaries

vs. B-29 Superfortress: Tu-4 approximately 3-5% heavier with marginally reduced performance due to inferior Soviet metallurgy and engines

vs. B-36 Peacemaker: American intercontinental bomber had 8,000+ km range and 435,000 lb MTOW, making B-36 far more capable strategically

vs. Tu-16 "Badger": Jet successor offered 900+ km/h speed, similar range, entered service 1954 rendering Tu-4 obsolete

Legacy

The Tu-4 gave the Soviet Union strategic bombing capability during the critical early Cold War years when the USSR developed its nuclear arsenal. While technologically derivative, the reverse-engineering program demonstrated Soviet industrial capacity and provided invaluable experience in heavy aircraft construction.

China received 10 Tu-4s in 1953 (designated Tupolev H-4), operated until the mid-1960s. These were the only Tu-4 exports.

The aircraft influenced subsequent Tupolev designs, with the company's long-range bomber lineage (Tu-16, Tu-22M, Tu-95, Tu-160) tracing conceptual origins to lessons learned from the Tu-4 program.

Related equipment

Related sections

Technical glossary

Strategic bomber : Heavy aircraft designed for long-range missions targeting enemy heartland infrastructure and industry

Reverse engineering : Disassembling and analyzing existing technology to recreate design and manufacturing processes

Turbosupercharger : Exhaust-driven compressor maintaining engine power at high altitude

Pressurized cabin : Sealed compartment maintaining sea-level atmospheric pressure for crew comfort and efficiency at altitude

Remote turret : Gun installation controlled from separate gunner position via electronic/hydraulic systems