- Length: 99 ft.
- Wingspan: 141 ft. 3 in.
- Height: 29 ft. 7 in.
- Wing Area: 1,736 sq. ft.
- Empty Weight: 74,500 lbs.
- Loaded Weight: 120,000 lbs.
- Maximum Takeoff Weight: 133,500 lbs.
- Crew: 11
- Maximum Speed: 310 knots (357 mph)
- Cruising Speed: 190 knots (220 mph)
- Combat Radius: 3,250 miles
- Rate of Climb: 900 ft./min.
- Service Ceiling: 33,600 ft.
- Power Plant: 4 × Wright R-3350-23 turbosupercharged radial engines, 2,200 hp each
- 12 × .50 cal. M2 Browning machine guns in remote controlled turrets
- 20,000 lbs. of bombs (standard load)
One of the most advanced bombers of World War II, design of the Boeing B-29 began in the late 1930s. In 1939, the initial design was presented to the Army Air Corps who, while impressed, requested an increase in defensive armament and the addition of self-sealing fuel tanks. These changes were incorporated and three initial prototypes were requested in 1940. The following year, the Army Air Corps examined a mock-up of the aircraft and were sufficiently impressed that they ordered 264 B-29s before ever seeing the aircraft fly. The aircraft first flew on September 21, 1942, and testing continued through next year.
Among the features incorporated into the B-29 were a fully pressurized cabin and remote-controlled machine gun turrets. Designed as a high-altitude daytime bomber, the aircraft was capable of reaching 40,000 ft., allowing it to fly higher than most Axis fighters. Dubbed the "Superfortress" as a nod to its predecessor the B-17 Flying Fortress, the B-29 was beset with problems throughout its development. The most common of these involved issues with the aircraft's Wright R-3350 engines which had a habit of overheating and causing fires. A variety of solutions were ultimately designed to counter this problem.
A highly sophisticated aircraft, problems persisted even after the B-29 entered production. Built at Boeing plants in Renton, WA and Wichita, KS, contracts were also given Bell and Martin who built the aircraft at plants in Marietta, GA and Omaha, NE respectively. Changes to the design occurred so frequently in 1944, that special modification plants were built to alter the aircraft as they came off the assembly line. Many of the problems were the result of rushing the aircraft in order to get it into combat as quickly as possible.
The first B-29s arrived at Allied airfields in India and China in April 1944. Originally, the XX Bomber Command was to operate two wings of B-29s from China, however this number was reduced to one due to a lack of aircraft. Flying from India, B-29s first saw combat on June 5, 1944, when 98 planes struck Bangkok. A month later, B-29s flying from Chengdu, China struck Yawata, Japan in the first raid on the Japanese home islands since the Doolittle Raid in 1942. While the aircraft were able to attack Japan, operating the bases in China proved costly as all supplies needed to be flown in over the Himalayas.
The problems of operating from China were averted in the fall of 1944, following the US capture of the Marianas Islands. Soon five major airfields were constructed on Saipan, Tinian, and Guam to support B-29 raids on Japan. Flying from the Marianas, B-29s struck every major city in Japan with increasing frequency. In addition to destroying industrial targets and firebombing, B-29s mined harbors and sea lanes damaging Japan's ability to resupply its troops. Though meant to be a daytime, high-altitude precision bomber, the B-29 frequently flew at night on carpet-bombing incendiary raids.
In August 1945, the B-29 flew its two most famous missions. Departing Tinian on August 6, the B-29 Enola Gay, Colonel Paul W. Tibbets commanding, dropped the first atomic bom on Hiroshima. Three days later the B-29 Bockscar dropped the second bomb on Nagasaki. Following the war, the B-29 was retained by the US Air Force and later saw combat during the Korean War. Flying primarily at night to avoid Communist jets, the B-29 was used in an interdictive role.
Following World War II, the USAF embarked on a modernization program to enhance the B-29 and correct many of the problems that had plagued the aircraft. The "improved" B-29 was designated the B-50 and entered service in 1947. That same year, a Soviet version of the aircraft, the Tu-4, began production. Based on reverse-engineered American aircraft downed during the war, it stayed in use until the 1960s. In 1955, the B-29/50 was withdrawn from service as an atomic bomber. It continued in use until the mid-1960s as an experimental test bed aircraft as well as an aerial tanker. All told, 3,900 B-29s were built.