Tupolev Tu-4

Tupolev

Industry	Aerospace, Defense
Founded	1922
Headquarters	Moscow , Soviet Union (now Russia)
Products	Aircraft including Tupolev Tu-4 strategic bomber

Template:Infobox aircraft

The Tupolev Tu-4 (Russian: Туполев Ту-4; NATO reporting name: Bull) was a piston-engine strategic bomber operated by the Soviet Air Force from the late 1940s through the mid-1960s. This aircraft was essentially a reverse-engineered copy of the American Boeing B-29 Superfortress, reconstructed from B-29s that had made emergency landings on Soviet soil.

Design and development

Near the conclusion of World War II, the Soviet Union recognized the necessity of possessing a strategic bombing platform comparable to that of Western Allied forces. At the war’s outset, the Soviet VVS operated the indigenous four-engine heavy bomber, the Petlyakov Pe-8, but its complex engines and limited production—only 93 units by war’s end—rendered it outdated. Meanwhile, the U.S. executed regular bombing missions over Japan utilizing B-29 Superfortresses launched from remote Pacific bases. Responding to this threat, Joseph Stalin mandated the creation of an equivalent bomber.

The United States declined twice to supply B-29 bombers to the USSR under the Lend-Lease program. Nevertheless, in 1944, four B-29s were forced to make emergency landings within Soviet territory; one crashed after its crew bailed out. Due to the terms of the Soviet–Japanese Neutrality Pact, which kept the USSR neutral in the Pacific conflict, these bombers were interned and retained by Soviet authorities. Despite American demands for their return, the Soviets refused. Three operable B-29s were flown to Moscow and handed over to Tupolev’s design bureau (OKB). One was dismantled for study, another used for flight testing and crew training, and a third served as a reference standard. These aircraft represented three different variants from two production plants—Boeing-Wichita and Boeing-Renton—and only one featured deicing boots similar to those later installed on the Tu-4. The fourth B-29 was eventually returned along with its crew after Soviet entry into the war against Japan following the atomic bombing of Hiroshima.

Stalin instructed Tupolev to replicate the Superfortress as quickly as possible rather than continue development on his own ANT-64/Tu-10 design. The reverse engineering process engaged approximately 900 factories and research centers, completing design work within a year and producing around 105,000 drawings. By the second year, Soviet industry aimed to manufacture twenty copies ready for state trials.

Since Soviet manufacturing employed metric measurements, matching U.S. customary sheet aluminum thicknesses was impossible; metric gauge metals differed in thickness. New alloys and materials unfamiliar to Soviet industry had to be introduced, requiring extensive redesign efforts to accommodate these differences while reducing official strength margins to avoid further modifications. Despite these hurdles, the prototype Tu-4's weight exceeded that of the B-29 by only about 340 kilograms—less than one percent.

Pressure from Tupolev, Stalin, and government officials demanded an exact duplicate of the original B-29 to streamline production. Tupolev faced significant opposition when attempting to substitute some components with existing or superior Soviet equipment. Every modification underwent rigorous scrutiny and prolonged bureaucratic approval processes; for example, authorization from a senior general was necessary even to utilize domestically produced parachutes. Differences between the Tu-4 and B-29 were limited primarily to sheet metal gauges, engines, defensive armament, radio equipment (the Tu-4 employed radios similar to those used in lend-lease B-25s instead of those found in interned B-29s), and identification friend or foe (IFF) systems due to incompatibility with American IFF technology.

The Tu-4’s powerplants were Shvetsov ASh-73 radial engines—a development based on the Wright R-1820 but unrelated to the Wright R-3350 engines used by the B-29. The ASh-73 also powered some remaining obsolete Petlyakov Pe-8 bombers whose production had been curtailed due to prioritization of other programs. The bomber’s remote-controlled gun turrets were redesigned to mount Soviet Nudelman NS-23 cannons with greater range and firepower than their American counterparts. Additional modifications addressed engine and propeller reliability issues discovered during testing, with equipment upgrades continuing throughout operational service.

The maiden flight of the Tu-4 occurred on 19 May 1947 under test pilot Nikolai Rybko. Production commenced immediately thereafter, with large-scale service entry by 1949. The aircraft was publicly unveiled during a flypast at Tushino Aviation Day on 3 August 1947: initially three aircraft flew overhead—Western observers assumed these were simply three of the original interned B-29s—but when a fourth appeared moments later, it became evident that a full-scale reverse engineering effort had been accomplished.

The introduction of the Tu-4 caused alarm within the United States Air Force, as its range permitted one-way strikes against cities such as Chicago or Los Angeles without refueling (although New York would have required aerial refueling even for a one-way mission). This threat likely influenced joint US-British air combat exercises conducted in 1948 involving squadrons of B-29s. These tests, organized by the RAF Central Fighter Establishment alongside US B-29 units, demonstrated tactics for intercepting bombers like the B-29/Tu-4 using jet fighters such as Gloster Meteors and de Havilland Vampires.

To extend operational range, Soviet engineers developed four distinct aerial refueling systems; however, only a limited number of aircraft were equipped with these before production shifted focus toward more advanced designs like the Tupolev Tu-16.

Operational history

Production of the Tu-4 concluded in the Soviet Union in 1952, with a total of 847 units manufactured. During the late 1950s, some of these aircraft were transferred to China. Numerous experimental models were developed, providing valuable insights that propelled the Soviet strategic bomber initiative forward. Throughout the 1960s, Tu-4s were gradually phased out from Soviet military use, replaced by more modern bombers such as the jet-powered Tupolev Tu-16 (introduced in 1954) and the turboprop Tupolev Tu-95 (introduced in 1956). By the early 1960s, the remaining Tu-4s in Soviet service were primarily assigned to transport roles or utilized as airborne laboratories. Notably, a Tu-4A was the first Soviet plane to deliver a nuclear weapon, specifically the RDS-3.

Variants

File:Tu-4 .jpg

Tu-4 displayed at China Aviation Museum

Tu-4

primary production model, initially designated B-4

Tu-4 Variants without specific designations:

Tu-4 equipped for ELINT and ECM missions

Tu-4 serving as a mothership for the DFS 346A. (Note: other DFS346 prototypes were carried by one of the Boeing B-29s interned during World War II.)

Tu-4 modified to carry escort fighters under Project Burlaki

Tu-4 converted into remotely piloted target drones from retired bombers

Tu-4 adapted as an aerial fuel tanker

Tu-4 utilized as test platforms for various in-flight refuelling systems (four distinct configurations tested)

Tu-4 configured for radiation reconnaissance missions

Tu-4 functioning as a communications relay aircraft

Tu-4A

Nuclear-capable bomber variant designed to test Soviet nuclear devices including RDS-1, RDS-3, and RDS-5, capabilities absent in the standard Tu-4

Tu-4D

Troop transport conversion with approximately 300 units modified; also referred to as Tu-76

Tu-4K/KS

Anti-shipping variant armed with KS-1 Komet missiles mounted between wing engines

Tu-4LL

Engine testbed for multiple powerplants including the Mikulin AM-3 jet engine, Ivchenko AI-20, Kuznetsov NK-4, and Kuznetsov 2TV-2F turboprops, as well as the Dobrynin VD-3K radial engine and AV-28 contra-rotating propellers

Tu-4NM

Drone carrier variant carrying underwing Lavochkin La-17 unmanned aerial vehicles

Tu-4R

Designed for long-range reconnaissance missions

Tu-4T

Paratrooper transport version, produced in a single example

Tu-4TRZhK

Aircraft configured as a liquid oxygen tanker

Tu-4UShS

Navigational training aircraft

ShR-1

Test platform developed to assist with the development of bicycle-type landing gear for the Myasishchev M-4

UR-1/-2

Testbeds used for evaluating powered control systems intended for the Myasishchev M-4

File:KJ-1.jpg

KJ-1 at China Aviation Museum, Beijing

Tu-4 AWACS

Chinese prototype outfitted with KJ-1 AEWC radar for airborne early warning and control, powered by Ivchenko AI-20K turboprop engines. Two units were converted to enable Chinese monitoring of US nuclear tests conducted in the Pacific.

Tu-70

Airliner variant that did not enter mass production.

Tu-75

Cargo transport derivative that likewise did not reach mass production.

Tu-79

Variant powered by M-49TK engines.

Tu-80

Long-range bomber prototype that never proceeded to mass production.

Tu-85

Another long-range bomber development project that was not mass-produced.

Tu-94

Tu-4 equipped with Kuznetsov TV-2 turboprop engines.

Operators

Template:USSR

• Soviet Air Force

Between 1948 and the early 1960s, the Soviet Air Force operated a fleet of 847 Tupolev Tu-4 bombers, primarily utilized as long-range strike aircraft. The initial unit to transition to the Tu-4 was the 185th Guards Aviation Regiment, part of the 13th Guards Bomber Aviation Division, based at Poltava Air Base in the Ukrainian SSR. Crew training took place in Kazan at the 890th long-range bomber regiment, which was converted into a dedicated training formation. Pilots from the 890th had significant experience flying American Boeing B-17 Flying Fortress and Consolidated B-24 Liberator bombers. In March 1949, the 52nd Guards Heavy Bomber Aviation Regiment began receiving Tu-4 aircraft; later, in 1953, the 121st Guards were equipped with Tu-4Rs.

Starting in 1954, the introduction of Tupolev Tu-16 bombers initiated the gradual retirement of Tu-4s from frontline service, followed by further replacements with Tupolev Tu-95 bombers from 1956 onward. Aircraft withdrawn from combat roles were reassigned to transport functions.

Template:PRC

• People's Liberation Army Air Force

On 28 February 1953, China received ten Tu-4 heavy bombers as a gift from Joseph Stalin, with an additional two units configured for navigation training delivered to Beijing in 1960. Between 1970 and 1973, eleven of these Tu-4s were upgraded with AI-20K turboprop engines. The People's Liberation Army Air Force (PLAAF) retired its last Tu-4 in 1988.

In 1969, China embarked on developing its first airborne early warning system based on the Tu-4 platform, known as the KJ-1. This project featured a Type 843 rotodome mounted above the fuselage. However, excessive clutter interference prevented the KJ-1 from meeting PLAAF operational standards, leading to cancellation of the program in 1979 despite proposals for further developments using the Tu-4 airframe. Due to its obsolescence, the Tu-4 was excluded from future airborne early warning projects. The sole prototype is preserved and exhibited at the PLAAF museum north of Beijing.

Survivors

File:KJ-1 (Tupolev Tu-4).jpg

China Aviation Museum, KJ-1.

File:WuZhen-5 under the wing of an aircraft carrier - 2.jpg

China Aviation Museum, Tupolev Tu-4.

File:Tu-4-2008-Monino.jpg

Tupolev Tu-4 at Monino

Tu-4 4114 (c/n 2805601), formerly KJ-1 AEWC, "4114"

Currently preserved at Datangshan, China

Tu-4 4134 (c/n 2205008), "4134"

Housed at Datangshan, China

Tu-4 unknown (c/n 2805103), designated "01"

Exhibited at the Central Air Force Museum, located in Monino, Russia