The redesign was supposed to increase internal fuel capacity while reducing the number of tanks, but the more powerful engines consumed fuel faster. That penalty joined the Il-4's heavy control forces and demanding long-range workload. Finnish and Soviet operators continued to find uses for the aircraft after the Second World War, and some remained in service into the Soviet space-race era. The Il-4 could be tiring and inefficient without being mechanically fragile. Reliability inherited from the DB-3 prolonged its value after the design's flying qualities and performance were no longer modern.
Notable Point · 32:14-34:20
Fuel thirst and handling did not erase Il-4 reliability
A simplified fuel system could not offset thirstier engines, yet inherited dependability kept the difficult Il-4 useful after the war.