Hi!
http://alternathistory.com/passazhirskii-variant-samoleta-bb-2
"It is considered that the IL-12 is the firstborn passenger of the Design Bureau. This is only partly true. In 1935, S. V. Ilyushin, in an initiative order, proposed a passenger version of the BB-2 (TsKB-30) bomber. The opening was detailed enough, as evidenced by the documents found. Below we present the full text of the memorandum, signed by the head of the brigade No. 3, S. V. Ilyushin. The oldest employee of the OKB - E. S. Chernikov, - on the old tracing paper restored the look and layout of this interesting aircraft. "
https://en.wikipedia.org/wiki/Ilyushin_DB-3
"The genesis of the DB-3 lay in the BB-2, Sergey Ilyushin's failed competitor to the Tupolev SB. Ilyushin was able to salvage the work and time invested in the BB-2's design by recasting it as a long-range bomber, again competing against a Tupolev design, the DB-2, to meet the stringent requirements of an aircraft capable of delivering a 1,000 kg (2,200 lb) bombload to a range of 3,000 km (1,900 mi) at a maximum speed no less than 350 km/h (220 mph). 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.
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. To speed the construction process, it had a wooden fuselage and fin with metal wings and tail surfaces. It made its first flight in the summer of 1935 and proved to be stable, easily controllable and highly maneuverable; it performed the first loop made by a twin-engined aircraft in the Soviet Union. 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.
The real prototype of the DB-3 was called the TsKB-30 and it was completed in March 1936. It had a number of improvements over the TsKB-26, notably an all-metal structure, an extended nose, an aft-sliding canopy with a fixed windscreen and improved engine cowlings. It successfully passed the State acceptance trials and was ordered into production in August 1936 as the DB-3, although some sources refer to this initial series as the DB-3S for seriynyy (series-built)."
"TsKB-30First real prototype. Later modified, including removal of armament, for long-range record attempts as the "Moskva". It flew from Moscow to Spassk-Dalny (7,580 km (4,710 mi)) in 24 h 36 min (an average speed of 307 km/h (191 mph)) mostly at 7,000 m (23,000 ft) under control of Vladimir Kokkinaki and A. M. Berdyanskij, then from Moscow to Miscou Island (New Brunswick, Canada) in 22 h 56 min. covering 8,000 km (5,000 mi) at 348 km/h (216 mph) average airspeed (Kokkinaki and Mikhail Gordienko)."
TsKB-26 prototype.
http://massimotessitori.altervista.org/sovietwarplanes/pages/db3-il4/tapanidb3/TsKB-26-prototype.htm
TsKB-30 Moskva record aircraft.
http://massimotessitori.altervista.org/sovietwarplanes/pages/db3-il4/tapanidb3/moskva.htm
