Icons of Aviation History: B-25 Mitchell

The B-25 medium bomber is most famous for its part in the Doolittle raid over Tokyo. But it was an extremely versatile aircraft that carried out multiple roles in every theater of the war, for the US Army, Navy and Marines as well as for the British and Soviet air forces.

B-25 Mitchell on exhibit with the Commemorative Air Force in Phoenix AZ

In 1938, the United States Army Air Corps was in the midst of a frantic expansion, as it became more and more apparent that the world was heading towards war and the US was not equipped to face it. In virtually every aspect of modern war, America was far behind its potential enemies.

When the Army issued a request in March 1939 for new medium bomber designs, it wanted a capability to deliver 2400 pounds of bombs over 1200 miles at an average speed of at least 300mph. One of the companies that submitted a proposal was North American Aviation. North American had submitted proposals in previous years and none had ever been selected, but now they learned from those earlier designs and pushed them ahead.

The new design was labeled “NA-62”. It called for a twin-engine bomber powered by the Wright R-2600-9 radial engine, with two vertical tail fins, powered gun turrets with five machine guns, and a bomb load of 3600 pounds. The Martin aircraft company, meanwhile, had submitted a proposal of their own with similar capabilities. The Air Corps liked them both, and ordered both into production. The Martin bomber became the B-26 Marauder, and North American’s bid became the B-25 Mitchell.

North American hurriedly built a new factory in Kansas City KS, and installed another B-25 production line in its main plant in Inglewood CA. By 1942, several changes had been made to improve the bomber,  and the new B-25B model began rolling off the assembly lines. Modifications continued to be added throughout the war, and at one point North American was making different models at each of its assembly lines. By the time the final B-25J model appeared, the engines had become more powerful, there were more machine guns for defense, and the bomb load had gotten bigger. There were also photoreconnaissance, transport, and weather monitoring versions, and a specialized fire-support “gunship” variant that packed up to 14 .50-caliber machine guns into the nose and turrets for strafing ground targets, while another alternative mounted a huge 75mm cannon for use against bunkers or small ships. The Navy had its own model called the PBJ for anti-submarine duty and coastal patrol, which carried torpedoes or depth charges. Export versions were also sent to England, Canada, China and Holland, and a few were sent to the Soviet Union. In all, about 10,000 B-25s were manufactured, and they continued in use until the early 1950s.

Each bomber carried a crew of six. The pilot and co-pilot sat in the cockpit, with the bombardier (who doubled as the navigator) below them in the Plexiglas nose turret. The engineer sat behind the cockpit, and manned the upper gun turret when necessary, likewise, the radio operator also doubled as the waist gunner. And the tail gunner sat in the back by himself.

The Mitchells served in every theater of the war, but most were assigned to the Pacific, where their ability to use short runways was helpful on small airfields, and their range gave them enough reach to deliver bomb loads to Japanese-occupied islands. By the end of the war, B-25s based on Okinawa were flying missions against targets in Japan. The bomber had originally been designed with the intention that its defensive turrets would provide enough firepower to defend it against enemy fighters, but hard experience soon shattered that illusion, and the bombers were usually escorted by friendly fighters.

The most famous of the B-25’s missions came in April 1942, when 16 B-25s, stripped of unnecessary equipment, took off from the US carrier Hornet and attacked Japan, dropping bombs on Tokyo. The actual damage was only slight, but the psychological impact was enormous: it gave a much-needed boost to American morale, and also scared the Japanese and led them into a final effort to lure out and destroy the American aircraft carriers—which ultimately led to the decisive Battle of Midway.

After the war, many B-25s were converted to civilian use as transports, cargo planes, or firefighters. Because of this, around 100 WW2-era Mitchells still survive, many of them in flyable condition.


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