That there were senior officers of the US Army Air Corps who were well aware of the need to procure long-range strategic bombers had been made clear in the entry dealing with the Boeing B-17. In addition to the long and drawn out process of getting B-17s into squadron service, the USAAC had also initiated procurement of more potent aircraft, ordering a prototype XBLR-1 (Experimental Bomber Long Range-1) from Boeing, which was built and flown as the XB-15. A competitive XBLR-2 (later XB-19) was ordered from Douglas Aircraft Company, and after it and the XB-15 had been evaluated, both were put into 'cold storage' until more powerful engines became available.

The outbreak of war in Europe in 1939 made it essential that USAAC planners should at least talk about long-range bomber projects, and the initial identification of such was VHB (very heavy bomber). When it seemed likely that such an aircraft might have to be deployed over the vast reaches of the Pacific Ocean the identification VLR (very long-range) seemed more apt, and it was the VLR project which General Henry H. ('Hap') Arnold, head of the USAAC, got under way at the beginning of 1940.

Requests for Proposals were sent to five US aircraft manufacturers on 29 January 1940: in due course design studies were submitted by Boeing, Consolidated, Douglas and Lockheed, these being allocated the respective designations XB-29, XB-32, XB-31 and XB- 30. Douglas and Lockheed subsequently withdrew from the competition, and on 6 September 1940 contracts were awarded to Boeing and Consolidated (Convair) for the construction and development of two (later three) prototypes of their respective designs. Convair's XB-32 Dominator was the first to fly, on 7 September 1942, but extensive development delayed its entry into service.

Boeing, because of the company's foresight, was much further along the design road in 1940, and being able to convince the USAAC that they would have production aircraft available within two or three years, had received orders for more than 1,500 before a prototype was flown. The reason for the advanced design state of Boeing's proposal was due to the fact that as early as 1938 the company had offered to the USAAC its ideas for an improved B-17, with a pressurised cabin to make high-altitude operations less demanding on the crew. While there was then no requirement for such an aircraft, the US Army encouraged Boeing to keep the design updated to meet the changing conditions of war. This was reflected by the designs identified as Models 316, 322, 333, 334 and 341. The design for the XB-29 was a development of the Model 341, designated Model 345, and the first of the prototypes made its maiden flight on 21 September 1942.

The USAAC's specification had called for a speed of 400 mph (644 km/h), so the XB-29 had a high aspect ratio cantilever monoplane wing rnid-set on the circular- section fuselage. Because such a wing would entail a high landing speed, the wide-span trailing-edge flaps were of the Fowler type which effectively increased wing area by almost 20 per cent, thus allowing a landing to be made at lower speed. Electrically- retractable tricycle landing gear was provided and, as originally proposed by Boeing, pressurised accommodation was included for the flight crew. In addition, a second pressurised compartment just aft of the wing gave accommodation to crew members who, in the third XB-29 and production aircraft, sighted defensive gun turrets from adjacent blister windows. The crew and aft compartments were connected by a crawl- tunnel which passed over the fore and aft bomb bays. The tail gunner was accommodated in a pressurised compartment, but this was isolated from the other crew positions. The powerplant consisted of four Wright R-3350 Cyclone twin-row radial engines, each with two General Electric turbochargers mounted one in each side of the engine nacelle. The 16 ft 7 in (5.05 m) diameter four-blade metal propellers were of the constant-speed and fully-feathering type.

Prototype production was followed by 14 YB-29 service test aircraft, the first of these flying on 26 June 1943. Deliveries of YB-29s began almost immediately to the 58th Very Heavy Bombardment Wing (VHBW), a unit which had been established on 1 June in advance of the first flight. B-29 production was the largest aircraft manufacturing project undertaken in the USA during World War 11, with literally thousands of sub- contractors supplying components or assemblies to the four main production plants: Boeing at Renton and Wichita; Bell at Mariettal Georgia; and Martin at Omaha, Nebraska.

Deliveries of production B-29s started in the autumn of 1943, and these began to equip the 58th VHBW so that it could proceed with training and get groups ready for operational service. One of the tricky questions was where to send the units initially, for the Allied/US agreement to end the war in Europe first would suggest their deployment against Germany and German- occupied territories. However, as 1943 was nearing its end, the situation in the Far East suggested that they could be used more effectively in that area, and the decision was made to send them to operate in the theatre for which they had been designed.

On 4 April 1944, the 20th Air Force was established to operate the B-29s, but as at that time no island bases were available from which the B-29s could strike at the Japanese home islands, preparations had already been made for them to operate initially from bases in China. Something like half a million Chinese farmers and peasants laboured with simple hand tools to create four airfields for the B-29s in the Chengtu area of Szechwan province, and the first aircraft landed at Kwanghan air base on 24 April 1944. By 10 May all four bases were operational and the first attack against a Japanese home island target, the Imperial Iron and Steel Works at Yawata, Kyushu, was made by 77 aircraft of XX Bomber Command on 15 June 1944. There were many problems to these operations from the Chinese bases, not least of which was logistics. about 150 B-29s were used continually to haul essential fuel and supplies to Kunming, over the Himalayan 'hump' from India, thus making it possible for 100 B-29s to remain operational. But it was not until the establishment of bases on Saipan, Guam and Tinian in the Marianas that the major B-29 offensive could be launched against Japan.

The first of XXI Bomber Command's Superfortresses landed on Saipan's Isley Field on 12 October 1944; Tinian's first airstrip was operational in late December; and that on Guwn on 2 February 1945. But the answer to the question of how to employ the B-29s most effectively was not resolved until the night of 9/10 March 1945, when 334 aircraft flying from Guam, Saipan and Tinian set out to attack Tokyo, some 1,600 miles (2 575 km) distant. When they returned they had recorded the most devastating air attack ever made, with 83,793 people dead, 40,918 injured and 1,008,005 rendered homeless.

This was to be the continuing pattern for XXI Bomber Command, while XX Bomber Command reduced Formosa's towns and docks to little more than rubble. It remained only for the B-29s Enola Gay and Bock's Car, of the 393rd Bombardment Squadron, to drop the world's only operational atomic bombs over Hiroshima and Nagasaki on 6 and 9 August 1945 respectively to bring World War 11 to a close. In these closing stages XXI Bomber Command B-29s had dropped some 160,000 tons (162 560 tonnes) of bombs on Japanese targets, averaging 1,193 tons (1 212 tonnes) per day during the last three months: the USAAC's VLR project was justified.

B-29 production totalled 1,644 from Boeing's Wichita plant, with 668 built by Bell and 536 by Martin. The Renton plant produced only B-29As, with slightly increased span and changes in fuel capacity and armament: production continued until May 1946 and totalled 1,122 aircraft. 

Nicknames: Washington (RAF name for B-29s loaned to the UK between 1950-1958); Bull (NATO code name for Russian TU-4, a near-exact copy of the B-29).

Specifications:

Engines: Four 2,200-hp Wright R-3350-23-23A/-41 Cyclone 18 turbocharged radial piston engines.
Weight: Empty 70,140 lbs., Max Takeoff 124,000 lbs.
Wing Span: 141ft. 3in.
Length: 99ft. 0in.
Height: 29ft. 7in.

Performance:
Maximum Speed: 358 mph
Cruising Speed: 230 mph
Ceiling: 31,850 ft.
Range: 3,250 miles

Armament:
wo 12.7-mm (0.5-inch) machine guns in each of remote-controlled turrets, plus three 12.7-mm (0.5-inch) machine guns, or two 12.7-mm guns and one 20-mm cannon in the tail turret.

Number Built: 3,970

Number Still Airworthy:  One