Named in honour of the fearless US Army Air Corps officer who was court-martialled in 1924 for his tiresome (to officialdom) belief in air power, the B-25 - designed by a company with no previous experience of twins, of bombers or of high performance warplanes - was made in larger quantities than any other American twin-engined combat aircraft and has often been described as the best aircraft in its class in World War II. Led by Lee Atwood and Ray Rice, the design team first created the Twin-Wasp powered NA-40, but had to start again and build a sleeker and more powerful machine to meet revised Army specifications demanding twice the bomb load (2,400 lb, 1,089 kg). The army ordered 184 off the drawing board, the first 24 being B-25s and the rest B-25As with armour and self-sealing tanks. The defensive armament was a 0.5 in gun manually aimed in the cramped tail and single 0.3 in manually aimed from waist windows and the nose; bomb load was 3,000 lb (1,361 kg). The B had an electrically driven dorsal turret and a retractable ventral turret, both containing twin 0.5 in machine guns; the tail gun having been removed. On 18 April 1942, 16 B-25Bs led by Lt Col Jimmy Doolittle made the daring and morale-raising raid on Tokyo, having made free take-offs at gross weight from the carrier Hornet 800 miles distant. Extra fuel, external bomb racks and other additions led to the C, supplied to the RAF, China and Soviet Union, and as PBJ-1C to the US Navy. The D was similar, but built at the new plant at Kansas City. In 1942 came the G, with solid nose fitted with a 75mm M-4 gun, loaded manually with 21 rounds. At first two 0.5 in were also fixed in the nose, for flak suppression and sighting, but in July 1943 tests against Japanese ships showed that more was needed and the answer was four 0.5 in "package guns" on the sides of the nose. Next came the B-25H with the fearsome armament of a 75mm, 15 0.5 in guns (eight firing ahead, two in waist bulges and four in dorsal and tail turrets) and a 2,000 lb (907 kg) torpedo or 3,200 lb (1,451 kg) of bombs. Biggest production of all was of the J, with glazed nose, normal bomb load of 4,000 lb (1,814 kg) and 13 0.5 in guns supplied with 5,000 rounds. The corresponding attack version had a solid nose with five additional 0.5 in guns. Total J output was 4,318 and the last delivery in August 1945 brought total output to 9,816. The F-10 was an unarmed multi-camera reconnaisance version, and the CB-25 was a post-war transport model. The wartime AT-24 trainers were redesignated TB-25 and, after 1947, supplemented by more than 900 bombers rebuilt as the TB-25J, K, L and M. Many ended their days as research hacks or target tugs and one carried the cameras for the early Cinerama films.