Developmental History
Designed to incredibly difficult 1938 Navy spec, the G4M1 'Betty' Bomber was the Japanese Navy's premier heavy bomber in WWII. The British heavily influenced the Japanese Navy during the formative years of their naval air arm. One lesson they took to heart was the idea of supporting the carrier-based planes with land-based attackers, long-ranged multi-engined bombers. Mitsubishi wanted to create a four-engined bomber, but the Navy insisted that the new bomber be a twin. The new bomber made its first flight on October 23, 1939. Its remarkable long range and speed was achieved by depriving the aircraft of armor while providing it with huge fuel tanks in the wings. Since the tanks were not self-sealing the Betty was extremely vulnerable. Use in the Guadalcanal campaign revealed its flaws and its tendency to burst into flames when the wing tanks were punctured. This property was a delight amongst Allied fighter pilots. The Japanese crew was less enamored with this tendency. The G4M was called the Hamaki or “Flying Cigar” by its crews but Allied pilots referred to it as “The One-Shot Lighter”.
The "Betty" played for the heavy bombers the same role that the Zero played for the fighter of the Imperial Navy. Sovereign at the start of the Pacific War, it went on fighting and being produced until the bitter end, despite a growing inferiority facing the allied air opposition. The Betty made a spectacular entry in the Pacific War: as soon as the second day sinking two capital ships, the Prince of Wales and the Repulse off the Malaysian coast. In January of 1943, it added the heavy cruiser Chicago to its score during the battle of the Rennels Islands in the Solomons. The Betty was somewhat unique in that the bomb bay door was non-functional in flight. This meant the door was removed for bombing missions, and had a panel removed from it for carrying torpedoes. Only for transfer or reconnaissance missions was the door on the plane.
On February 20, 1942, while defending his carrier, the Lexington, against a bombing attack by nine G4M1s, Lieutenant (jg) Edward “Butch” O’Hare of the US Navy shot down five of the attackers. This was the first time ever that an American fighter pilot had shot down five enemy planes in a single sortie, and O’Hare won the Medal of Honor for this feat. Evading the tail cannon of his victims, he concentrated his fire on the port or starboard wing and engine. Each of his five victories either exploded, or lurched out of formation and dived for the sea in flames. Admiral Isoroku Yamamoto was flying in a G4M1 Model 12 when he was shot down and killed by P-38 Lightnings over Bougainville on April 18, 1943.
From 1943 onwards luck turned against it. It remained on the frontline only because there was no available replacement. The few progressions in armament and protection were not enough and the losses mounted. The increasing losses in the South Pacific forced the Japanese to sacrifice some of its range to protect the fuel tanks and equip the plane with fire extinguishers. Forced improvements to the model before obsolescence led to its replacement by the G4M2. The last G4M1 left the frontline in the autumn of 1944. In 1945 some survivors were employed to carry suicide devices to attack the allied ships around Okinawa. Having played such a prominent part in the opening phase of the Pacific War the G4M was to figure in the final drama of that conflict, when on August 19th, 1945 two G4M1s carried the Imperial delegation to Ie-Shima to discuss the final requirements for Japan's surrender, both painted white with green crosses. Total production of the G4M was 2,479 - a remarkably high figure for a Japanese medium or heavy bomber. The final word on the G4M Betty must be that it began its career in the Pacific with a rare blaze of glory, but in the majority of cases, aircraft of this type ended their careers in blazes of glory, with all too fatal results for the seven-man crews.
