Betty bomber crew positions
To meet the requirements, a Mitsubishi design team led by Kiro Honjo crafted an airplane called the G4M with fuel tanks in the wings that were not resistant to explosion when punctured during combat.
When carrying an 800-kg (1,768 lb) torpedo or the same weight in bombs, the Navy needed the bomber to fly at least 3,700 km (2,300 mi). At that time, the requirements were unprecedented for a twin-engine, land-based attack bomber: flying at a top speed of 398 kph (247 mph) and an altitude of 3,000 m (9,845 ft), the new bomber had to fly a distance of 4,722 km (2,933 miles) without a torpedo or equivalent weight in bombs. Only two months later, the Navy issued a specification to Mitsubishi for a NELL replacement. In July 1937, the new Mitsubishi G3M bomber (Allied codename NELL) went into service in China. Like its stablemate, Mitsubishi's Zero Fighter (see NASM collection for two examples), the Hamaki soldiered on long after it became obsolete, even dangerous, to fly wherever Allied interceptors prowled. From the first day of war until after the surrender, BETTY bombers saw service throughout the Pacific and Indian Oceans. The Japanese built more of them than any other bomber during World War II. The Allies called it the BETTY but to the men that flew the airplane, it was popularly, but unofficially, the 'Hamaki,' Japanese for cigar, in honor of the airplane's rotund, cigar-shaped fuselage. Few would know it by its official designation, the Navy Type 1 Attack Bomber.