The Yer-2 (DB-240) was a Soviet piston-engine strategic bomber that served in the Soviet Long Range Aviation during World War II. Originally developed as a passenger aircraft, the Stal-7, by Robert Ludwigovich Bartini, the aircraft had a range of 5,000 km. However, after Bartini's arrest in 1938, his design bureau proposed converting the aircraft into a strategic bomber to the Soviet leadership. After receiving approval, the Stal-7 was redesigned under the direction of the new chief designer, Vladimir Grigoryevich Yermolaev, and entered operational service in May–June 1941 under the designation Yer-2. The bomber did not become widely used due to its poor flight characteristics, frequent accidents, and engine fires. From 1940 to 1945, a total of 462 Yer-2 bombers of various modifications were built.
The Yer-2 was originally designed for M-106 engines. However, due to delays in their development, the aircraft was fitted with less powerful M-105 engines, which resulted in its relatively poor performance. The first Yer-2 production aircraft had a “MV-3” turret with a ShKAS machine gun instead of the upper turret “TAT-BT” with a heavy Berezin machine gun.
