In support of an official event 

The Museum will be closed Sunday, May 25
In addition, the Fourth Hangar will be closed Saturday, May 24

Access to the Presidential Gallery will be limited from May 15 to June 5
 

Four-Engine Bomber

In the summer of 1935, the Boeing Airplane Co. unveiled its Model 299, a remarkable four-engine, high-speed, long-range, heavy bomber which was eventually designated the B-17 Flying Fortress. This plane, although destined to change the complexion of aerial warfare, initially failed to convince the Army's General Staff of its merits and capabilities. As a result, the General Staff directed that the major portion of funds for the purchase of bombers be spent for cheaper two-engine Douglas B-18s, rather than more costly four-engine B-17s, believing the latter type an expensive and unnecessary luxury. 

Proving the Flying Fortress
As a result of the General Staff's decision, only 13 YB-17s and one YB-17A were ordered by mid-1937 as compared to 133 B-18s and 177 B-18As. The Air Corps was determined to prove the value of the four-engine B-17 with this handful of service test planes. It flew its YB-17s at every opportunity over the U.S. and even scheduled good will flights to South America to demonstrate the long-range capabilities of the plane. It eventually proved its point, and by the end of 1938, contracts for 39 additional B-17Bs were awarded. In addition, a new four-engine bomber, the Consolidated XB-24, was ordered on March 30, 1939. At the time World War II began in Europe in September 1939, the first B-17Bs were beginning to come off the production line. 

Pre-war Super Bombers
Although the Boeing B-17 was to gain greater fame, Boeing also designed and built an even larger four-engine bomber in the mid-1930s, the XB-15. Its design was actually begun before the B-17, but it did not make its first flight until 1937, more than two years after that of the B-17. With a wingspan of 149 feet, almost half again as large as the B-17, the XB-15 was the victim of lag in engine development -- there were simply no engines available which were powerful enough to give it the performance it deserved. Numerous test projects were made with the XB-15, but in 1943 it was relegated to the role of a cargo airplane and redesignated the XC-105. At the end of World War II, it was dismantled in Panama.

Douglas became involved with the super-bomber in 1935 when it began design of an enormous airplane having a 212-foot wingspan and a tricycle landing gear. Designated the XB-19, it made its first flight on June 27, 1941. Like the XB-15, the XB-19 was underpowered, and after numerous test projects were conducted with the plane, it also began carrying cargo. During WWII, its Wright radial engines were replaced by Allison in-line engines of greater power, but by the end of the war, bomber technology had far outdistanced the XB-19, making further development of the plane uneconomical. In 1949 the XB-19 was reduced to scrap metal at Davis-Monthan Air Force Base, Ariz.
 

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Boeing B-17G Flying Fortress
Douglas B-18 Bolo
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