Bombers with an extremely long range were in dire need for such missions, and this could be achieved by designing the entire wing as integral fuel tanks ad keeping the structure as light as possible, without and armor or self-sealing protection. Defensive weapons and armor protection for the crew were also kept to a minimum. To reduce the drag, bombs or torpedo were stored within a thick, cigar-like fuselage. The thin, wide wing contributed to obtain an excellent stability and maneuverability during flight. Using two 1530hp Mitsubishi "Kasei" type-11 radial engines, the G4M achieved a maximum speed of more than 420Km/h and an outstanding 4,200km or range. However, the 5,000 liters of fuel in the unprotected tanks made the bomber extremely vulnerable, and it soon became known to U.S. gunners as the "one-shot lighter."