The Russian Civil War pushed the Russian Empire out of World War 1 (1914-1918) and lasted until October of 1922 to which the Soviet Empire emerged from its ruins. From the remnants of the Imperial Russian Air Service was also formed the air branch of the Soviets recognized rather simply as the "Soviet Air Force". During the middle of 1924, the service called on local ingenuity to fulfill a long-range heavy bomber need and this resulted in the Tupolev concern taking the lead on the project.
The design would be a large undertaking for the recovering nation, powered by multiple engines and requiring the attention of multiple crewmen. All-metal construction (to include Duralumin corrugated skinning influenced by Hugo Junker's earlier work) would give it a modern appearance and advanced capabilities for the period. The end result was the Tupolev TB-1 by Andrei Tupolev - known to the company as the "ANT-4".
This aircraft became the largest all-metal aircraft to be constructed in the Soviet Union up to that point when it was unveiled in 1925. The selected engine series was the British Napier "Lion" of which two would be fitted to the wings (one per wing). A low-set monoplane wing mainplane was selected and a traditional single-finned tail unit used. A stepped cockpit was fitted at front of the slab-sided fuselage. A tail-dragger undercarriage arrangement was used.
A first-flight was recorded on November 26th of that year. After successful evaluation of the system it was ordered into serial production as the "TB-1".
Internally, the bomber was crewed by six. Structurally it held a length of 59 feet with a wingspan of 94.1 feet and a height of 16.8 feet. Empty weight was 10,000lb with a Maximum Take-Off-Weight (MTOW) of 15,015lb. Production forms were powered by the M-17 V-12 liquid-cooled inline piston engine developing 680 horsepower - these were licensed-built BMW VI series V-12 engines.
Performance-wise the aircraft was able to reach speeds of 110 miles per hour and comfortably cruise at nearly 100 miles per hour. Range was out to 620 miles and its service ceiling was 15,845 feet. Rate-of-climb was 595 feet-per-minute.
For point defense, the bomber was outfitted with 6 x 7.62mm Degtyaryov (DA) Machine Guns fitted at various positions about the frame. Provision was made for up to 2,205lb of conventional drop ordnance to be carried.
After completion of two prototypes, the TB-1's arrival as an operational weapon system was slow as there proved logistical issues in obtaining the required engines (the original Napier Lions) and aluminum. Serial production, therefore, did not begin until 1929 and lasted until 1932 by which point a total of 216 aircraft would be completed (not counting the two prototypes). Most of the lot were completed with a wheeled undercarriage though some sixty-six emerged with floats to serve on water (in the TB-1P torpedo bomber role). ANT-4bis became a third prototype while the G-1 designation marked designated transport version of the bomber.
The first available example was delivered for civilian service and flew from Moscow to New York City as a newsreel initiative. The voyage took 137 total flight hours to complete but nonetheless caused a sensation. From this point forward deliveries to the Soviet Air Force commenced and it soon became the service's standardized "heavy". The aircraft went on to serve the Air Force, Soviet Naval Aviation and passenger carrier Aeroflot before it met its end.
The TB-1 also became the focus of Soviet "parasite fighter" experimentation in which the large aircraft was to serve as mothership to smaller, recoverable fighters launched from her hold. This project was known by the name of "Zveno" and involved a pair of Tupolev I-4 biplane fighters.
The TB-1 series was superseded by the more-modern TB-3, also by Tupolev, in 1932. Eight hundred eighteen of this design followed.
Many TB-1 bombers ended their days as the aforementioned G-1 transports under the direction of Aeroflot.
Soviet Union
