He had redesigned the BB-2 to take advantage of the radial Gnome-Rhône Mistral Major 14Kdrs engine, for which the Soviets had purchased a license in 1934 as the M-85, and had begun construction of the prototype of the BB-2 2K-14 as the TsKB-26 that same year.

[1] The TsKB-26 was more of a proof-of-concept vehicle to validate Ilyushin's ideas on how to obtain long range than an actual bomber prototype.

[2] It went on to set six world records in its class, generally in payloads to height and speed over a 5,000 km (3,100 mi) closed circuit.

It passed the State acceptance trials and was ordered into production in August 1936 as the DB-3,[2] although some sources refer to this initial series as the DB-3S for seriynyy (series-built).

[3] The DB-3 was not a simple or easy aircraft to manufacture as Ilyushin had pushed the limits of the available construction technology to make it as light as possible.

For example, the spar in each wing panel had four parts which had to be riveted together and there were numerous welds that each had to be inspected by an X-ray machine, with many failures.

[4] Flight tests of the second example pre-production aircraft, conducted May–October 1937, revealed that it was slightly inferior to the TsKB-30 in performance, but still exceeded its requirements by a considerable margin.

In 1939, 30 DB-3s were supplied to the Republic of China Air Force during the Second Sino-Japanese War and they saw heavy action against Japanese targets in the Wuhan region from their bases in Sichuan (mostly used by the 8th Group), before being replaced by B-24 Liberators in 1943.

Two DB-3s were responsible for shooting down the neutral Finnish civilian Junkers Ju 52 passenger and transport plane Kaleva on June 14, 1940.

[8] On the night of August 7–8, 1941, fifteen DB-3T torpedo bombers of the Baltic Fleet dropped the first Soviet bombs on Berlin.

It was recovered in September 1988 and brought to the Irkutsk Aircraft Industrial Association (IAIA) factory on board an Ilyushin Il-76 transport.

[13] This aircraft should not be confused with the Ilyushin Il-4 (cn 17404) exhibited in the Victory Park collection of the Central museum of Great Patriotic War, Moscow.