The DB-3 / Il-4 was designed by Sergei Vladimirovich Ilyushin in 1936.
The DB-3 changed its name in 1940 and it became the Ilyushin Il-4.
The construction of the DB-3F / Il-4 was initially metal. After the German invasion, wood was used in the main spars. Wood also was used in the cabin floor, tail, and outer wing panels.
The cockpit had a wooden floor due to metal shortages.
Had a glazed nose with a simple MG mounting.
Most Il-4s had a cleat for towing an A-7 or G-11 glider.
Starting in 1942 the wings had wooden spars that replaced the metal.
Starting in 1942 the propellers were fully feathered.