The TB-3 was a Soviet Heavy Bomber that served with distinction with the Soviet Air Forces
The TB-3 bears more than a slight resemblance to it's predecessor, the TB-1. It has many of the same features of the TB-1 such as similar defensive armament, a similar outward appearance due to the use of corrugated metal skin, and low-set monoplane wings. However, the most visible difference between the two aircraft is also the most important difference. The TB-3 originally had four Mikulin M-17 engines. These engines were unreliable in service as they had a tendency to overheat very rapidly. Therefore, later TB-3's were fitted with four Mikulin M-34 engines. In both cases, the engines were in the leading edge of the wing,and each wing's leading edge contained two of said engines. The TB-1 however, had only two Mikulin M-17 engines in it's leading wing edge. The Soviet plane for its time was a game changer as it was the first monoplane to incorporate engines in the leading edges of the wings, and gave it an advantage over most other bombers at the time.
- ANT-6 Development Designation
- TB-3-4M-17F Initial Production model
- TB-3-4M-34 Improved version fitted with improved Mikulin M-34 Engines
- TB-3-4M-34R Improved Mikulin M-34R Engines mounted.
- TB-3-4AM-34RD Long range version with streamlining and metal propellers
- G-2 Transport model
The TB-3 saw extensive service in the Soviet Air Force. It entered service in 1932 and remained active in some squadrons all the way up to 1945 (although in most squadrons it was phased out of service in 1939).  It officially saw its first combat in the Sino-Japanese War during the Battle of Khalkhin Gol in 1939. The TB-3 served not just in the bombing role in that conflict. It also served as a transport because of constant accidents by the Ilyushin DB-3s serving in that role. It also fought in the Winter War against Finland. They were officially declared obsolete in 1939, but the aircraft were kept in serviceable condition. 516 of the bombers were also still in the Voyenno-Vozdushnye Sily when the Germans began Operation Barbarossa, and another 25 bombers were in service with the Soviet Navy.  . With the TB-3, representing 25% of the Soviet Bomber Force, it serving in World War II was an inevitability. The Tupolev bomber served with the 3rd Heavy Bomber Regiment performing night raids beginning on June 23rd, 1941. The TB-3 served with the Voyenno-Vozdushnye Sily in the bomber role in significant numbers until 1943, although they were used by some squadrons in limited numbers until 1945. The TB-3 also served in various other roles such as transport and even served as a transport plane for paratroopers.
By far the most unusual role played by the Soviet Bomber was its involvement in the Zveno Combinations. The Zveno (Link) was the brainchild of Vladimir Vakhmistrovin 1931 and involved attaching fighters equipped with bombs to the bomber to extend the reach of the aircraft. This unorthodox experiments were initially performed on a TB-1 known as Zveno 1. When the new Tupolev aircraft was introduced in 1932, trials with such experiments carried on with the TB-3. The Zveno 2 was a TB-3 with three I-5 fighters equipped with bombs carried on top of the wings. By 1941, such experiments were still being performed using the TB-3, however the planes carried by the TB-3 had changed to two Polikarpov I-16s.  This version is significant as it saw actual combat and in said attack successfully destroyed an important bridge. However, its debut in combat would be the only time this combination saw action, mainly due to the effects the fighters had on the performance on the bomber.
- Winchester, Jim. The Aviation Factfile: Aircraft of World War II. London: Amber Books Ltd, 2012.
- Winchester, Jim. X-Planes and Prototypes. New York: Sterling Publishing, 2015.