Boeing B-29 Superfortress
The Boeing B-29 Superfortress was the United States Army Air Forces' four-engined heavy bomber of the Second World War, designed by Boeing around pressurized crew compartments, remote-controlled gun turrets and the range to bomb Japan from distant island bases. First flown in 1942, it flew incendiary and mine-laying campaigns against Japan in 1944-45, and Silverplate B-29s dropped the atomic bombs on Hiroshima and Nagasaki. It served again in the Korean War, was retired in the early 1960s, and about two dozen survive, two of them still flying.
Why It Mattered
The B-29 began with a reach problem: in January 1940 the United States Army Air Corps asked five manufacturers for a four-engine bomber able to strike across an ocean and come home. Boeing's design grew into the most advanced propeller-driven bomber of the Second World War, and its development and production became the most expensive American weapons program of the war. From 1944 it carried the air war to Japan itself, first in daylight at high altitude and later in low-altitude incendiary raids and mine-laying against Japanese ports. In August 1945, modified B-29s dropped the atomic bombs on Hiroshima and Nagasaki, the only nuclear weapons ever used in combat.
Design Notes
Pressurization set the B-29 apart: it was the first bomber to house its crew in pressurized compartments, so men could work at high altitude in relative comfort. Its defensive guns sat in turrets that gunners operated by remote control, aiming through sights rather than from inside the turret. An analog computer-controlled fire-control system let one gunner and a fire-control officer direct four remote machine gun turrets at once. The airframe paired that equipment with a pressurized cabin, dual-wheeled tricycle landing gear and four Wright R-3350 engines. Those engines were the type's weak point at first: early R-3350s were beset with dangerous reliability problems and were cured only gradually. Production was too big for one company: four main-assembly factories, run by Boeing, Bell and Martin, shared the work of building the B-29.
Operational History
The XB-29 prototype first flew on September 21, 1942, lifting off from Boeing Field in Seattle, but the type was rushed and troubled, and it reached combat slowly. Combat began on 5 June 1944, when B-29s flew their first mission against Bangkok from bases in India. Raids on Japan followed from China, where all supplies had to be flown over the Himalayas, an effort that limited what the bombers could do. The answer was to capture the Mariana Islands, which would bring targets such as Tokyo within range; from Saipan, Tinian and Guam the campaign against Japan's cities grew through late 1944. High-altitude precision bombing produced poor results in the winds and cloud over Japan, so in early 1945 the Marianas command changed to low-altitude night raids using incendiary bombs. The incendiary campaign went on devastating most large Japanese cities, and B-29s also took up the mining of Japanese ports and shipping routes, strangling coastal traffic. On 6 August 1945 the type's most consequential mission was flown: a Silverplate B-29, Enola Gay, dropped the first atomic weapon used in combat on Hiroshima, Japan. Three days later a second Silverplate aircraft, Bockscar, dropped an atomic bomb on Nagasaki, and within days Japan accepted Allied surrender terms. B-29s flew again in combat during the Korean War of 1950–1953, at first by day, but after Soviet MiG-15 jets appeared, later raids were restricted to night missions.
Afterlife
The B-29 was retired in the early 1960s after 3,970 had been built, its bombing role taken over by jets. Britain flew the type as well: loaned aircraft were known as the Washington B.1 in RAF service from 1950 to 1954. The Soviet Union built the Tupolev Tu-4, an unlicensed reverse-engineered copy of the B-29, from aircraft interned during the war. Twenty-two B-29s are reported to survive to preservation, most of them on static display in museums. The two atomic-mission aircraft survive as museum pieces: Enola Gay, fully restored, is exhibited by the Smithsonian at its Steven F. Udvar-Hazy Center, and Bockscar is exhibited at the National Museum of the United States Air Force. Two airframes, FIFI and Doc, still fly, the last airworthy examples of the thousands built.