The Yermolayev Yer-2 was a long-range Soviet medium bomber used during World War II.
It was developed from the Bartini Stal-7 prototype airliner before the war.
It was used to bomb Berlin from airbases in Estonia after Operation Barbarossa began in 1941.
Production was terminated in August 1941 to allow the factory to concentrate on building higher-priority Ilyushin Il-2 ground-attack aircraft, it was restarted at the end of 1943 with new, fuel-efficient, Charomskiy ACh-30B aircraft Diesel engines.
Two prototypes of the Yer-2 series with two 1,050 hp M-105 engines.
Production version with two M-105 engines, 128 built.
One aircraft re-engine with two prototype 1,380 hp Mikulin AM-37 engines, the fastest of all Yer-2s.
The first diesel-powered Yer-2, with modified wings.
One converted with two 1,500 hp Charomskiy M-40F diesel engines.
Production model of the diesel-engine version.
Performance was excellent despite the poor reliability and rough running of the Charomskiy ACh-30B diesel engines.
Range increased 1,500 km (930 mi) from the version with M-105 engines.
Two aircraft from the Yer-2/ACh-30B production line were modified with a 12-seat VIP cabin, military equipment removed and long-range fuel tanks in the bomb-bay.
A third aircraft was converted from a Yer-2 and used for shuttle flights between Irkutsk and Moscow.
One aircraft was modified as an engine testbed for captured Argus As 014 pulse jet engines.
One production aircraft used as a testbed for the 2,200 horsepower (1,600 kW) Dobrotvorskii MB-100 engine in 1945.
The final model of the Yer-2 series was a 1941 production aircraft re-engine with ACh-30BF engines and redesignated as the Yer-4.
It had a slightly larger wingspan, increased take-off weight and improved armament.
The prototype was tested in December 1943 but did not enter production.