Drawing by Tapani Tuomanen
Sergey V.Ilyushin, chief of the 3rd Brigade of TsKB (Central Design Bureau) started to work on a two-engined long-range bomber in 1933, as a smaller and faster replacement for the large TB-3.
The prototype TsKB-26 was a simplified technological demonstrator, combining wooden fuselage and vertical stabilizer with metal wings and horizontal stabilizers, while the production aircraft was thought as an all- metal plane. A bomb bay was installed, but without racks and defensive armament. The engines were the two-row 14 cylinders M-85 radials of 765 hp, a licensed copy of the French Gnome-Rhone 14 Kdrs.
It is different from successive DB-3s for having a 52 cm shorter nose, a forward sliding canopy as that of early I-16s and a tail skid instead of a wheel, the front glazing and the lack of windows and of the escape hatch on the top of the nose.
The construction of TsKB-26 started in Zavod 39 in Moscow-Khodinka in June 1934; the plane made its first roll out at June 1, 1935, and was flown by test pilot Vladimir K.Kokkinaki few days later, showing good flight characteristcs. It reached a speed of 330 km/h at sea level amd 390 km/h at 3250 m.
On 1 May 1936, the plane flew during the Parade in Moscow, greatly impressing the Soviet leaders, and in the following year obtained many world records for its high performances: for example, it reached an altitude of 12101m with a 1000 kg payload, and in another occasion it flew 5000 km with a 1000 kg payload at an average speed of 325.4 km/h.
The plane looks painted in light grey (or silver?) overall with red engine cowlings.
Images from : DB3-Il-4 in Actiom Squadron Signal, and from the books of V. Kotelnikov.