APRIL 2016 | 11 When the U.S. Army Air Corps wanted a bigger bomber, Douglas Aircraft BY MICHAEL LOMBARDI On the shoulders of giants eventy five years ago, when it was rolled out of the Douglas Aircraft plant in Santa Monica, Calif., the XB-19 was hailed as the “Guardian of the Hemisphere.” The four-engine experimental bomber took off from Clover Field for its first flight in June 1941. At the time, it was the largest airplane in the world, with a wingspan greater than the first 747 that would follow many years later. And much like the legendary 747, the XB-19 had required a bigger building, bigger tools and a bigger imagination. Donald Douglas called it “a triumph of American initiative and engineering.” But only one was ever built. The Douglas XB-19 began in the mid-1930s as a U.S. Army Air Corps project and was designated the XBLR-2 (Experimental Bomber Long Range). It was an X-plane designed to test the limits of size, capacity and range. Boeing had worked on a similar project designated the XBLR-1, and later the XB-15. When introduced in 1937, the Boeing aircraft was the largest and heaviest ever flown in the United States. But the Army Air Corps wanted Douglas to go bigger. Preliminary design of the XB-19 began in July 1935 and although the size and scope of the project caused some delays, the biggest obstacle was budget. With escalating cost that quickly exceeded the original $1.4 million government contract, Douglas contributed an additional $4 million of its own funds to complete the project, which was not finished until May 1941. At 212 feet (65 meters), its wingspan was 63 feet (19 meters) more than the XB-15 and 17 feet (5 meters) greater than the early models of the 747. The XB-19’s empty weight of 86,000 pounds (39,000 kilograms) easily doubled the XB-15. It had a crew of 16 and HISTORICAL PERSPECT I V E accommodations for eight additional crew members, plus a large galley to prepare hot meals for long-range missions up to a maximum of 7,710 miles (12,400 kilometers). Douglas had indeed gone bigger. Designing the airplane was not considered a great challenge for Douglas engineers, who had been evolving bigger airplane designs and were working toward the four-engine DC-4E. What the Douglas workers found to be a problem, however, was installation of the massive amounts of equipment. Powerful airborne electrical systems were new in the 1930s and the XB-19 had one of the most powerful, with twin 15-kilowatt generators that powered four large radios and 24 intercom stations throughout the plane. It was one of the first planes to have an oxygen distribution system and the first to have power-boosted controls. The plane had a tricycle landing gear, a rarity at the time, and the main landing gear struts were so large that no tool was available to machine them—the closest were naval arsenal lathes used to manufacture 16-inch (40-centimeter) battleship guns. The voluminous hangar at the Douglas plant in Santa Monica housed the showpiece of XB-19 manufacturing—the largest jig used anywhere in the aircraft industry. The wings and center fuselage were built vertically as one piece in the jig, which was more than 200 feet (60 meters) long, 48 feet (15 meters) high and weighed 105,000 pounds (47,600 kilograms). Almost 200 workers were needed on the jig, distributed over seven different levels. When the aircraft’s huge sections were completed, Douglas consulted with the engineers who worked on the Golden Gate Bridge in San Francisco to move and join them together. On June 27, 1941, a crew of seven, led by Maj. Stanley Umstead, took off in the XB-19 from Clover Field, Santa Monica. Unnoticed in the crowd of onlookers was actress Carole Lombard, sitting on top of her Cadillac coupe; beside the car was actor Clark Gable. The airplane was transferred to Wright Field, Ohio, in January 1942, where it was used as a flying laboratory, contributing data and experience that assisted the design and operation of other large airplanes such as the Boeing B-29 and especially the Convair B-36, which assumed the mantle of America’s largest airplane in 1946. The 1940s were a period of accelerated technological advancement and the XB-19’s long development ensured its rapid obsolescence. By 1943 the usefulness of the airplane as a flying laboratory had come to an end. Its 2,000-horsepower Wright R-3350 radial engines were replaced with the unique 2,600-horsepower Allison V-3420 inline engines and it was redesignated the XB-19A and used as a cargo plane. On Aug. 17, 1946, the XB-19A made its final flight to Davis- Monthan Field in Arizona, where it eventually was scrapped. Despite its limited success, the size, complexity and audacity of the program served as a source of pride and inspiration for the men and women of Douglas Aircraft and, indeed, the entire fledgling U.S. aerospace industry. Most important, perhaps, it encouraged them to design bigger and better aircraft and take on seemingly impossible challenges. As Donald Douglas wrote, the XB-19 was “a tribute to the vision and daring of men who plan and build. It is the product of a thousand brains and million hands.” • MICHAEL.J.LOMBARDI@BOEING.COM responded with a giant—the XB-19 S
Frontiers April 2016 Issue
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