DB-4

The Ilyushin DB‑4 was a Soviet long‑range bomber prototype developed in the late 1930s as the next evolution of the successful DB‑3 family. Initiated in 1939, the project sought to increase payload, range and defensive capability by incorporating a strengthened airframe, more powerful Shvetsov M‑71 radial engines and an enlarged bomb bay that could carry up to 2,500 kg of ordnance. The aircraft featured a low‑drag, semi‑monocoque fuselage, retractable main gear, and a revised dorsal and ventral turret layout that improved crew survivability on high‑altitude missions. Though flight testing in 1941 demonstrated respectable performance – a top speed of 540 km/h, a service ceiling of 9,500 m and a range exceeding 3,500 km – production was halted in favor of the refined Il‑4, which borrowed most of the DB‑4’s aerodynamic refinements. The DB‑4’s brief development cycle nonetheless left a lasting imprint on Soviet bomber design, providing valuable data on high‑output engines and advanced defensive armament. Its legacy is evident in the reliability and combat effectiveness of later Ilyushin bombers that served throughout World War II and shaped post‑war strategic aviation concepts. Today, aviation historians regard the DB‑4 as a pivotal stepping stone toward modern long‑range strike aircraft.

Ilyushin

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Design & Classification