From the Planes You’ve (Probably) Never Heard Of Department of Wingspan, we bring you the Boeing XB-15 and Douglas XB-19.
In the days before aerial refueling, the main limiting factor of any bombing mission was range. The great Boeing B-17 Flying Fortress and Consolidated B-24 Liberator, fully loaded, were both capable of flying about 2,000 miles. The Boeing B-29 Superfortress, which ranged across the western Pacific Ocean improved on that, managing 3,250 miles with a load of bombs. But even before the outbreak of war, military planners had envisioned a bomber that could fly tremendous distances, one with a range of as much as 5,000 miles. Such a reach would make possible flights across the Atlantic on a single load of fuel. Once there, the bomber would be capable of attacking all points in Europe from bases in England. And it could even reach Japan from the US mainland, though it would be a one-way trip.
Boeing began construction of a long-range bomber in 1933 in response to the US Army Air Corps’ Project A, which called for a new bomber that could carry a 2,000 pound bomb load at 200 mph and cover what was then the fantastic distance of 5,000 miles. By 1935, the program became known as the “Bomber, Long Range” program. Boeing’s new plane would be known as the XBLR-1, or XB-15. At this point, Douglas joined the project with plans to develop their own mega-bomber that would be designated the XBLR-2, or XB-19.
Both aircraft were huge. The XB-15 had a wingspan of 149 feet, a length of 89 feet, and a height of 18 feet. The XB-19 was bigger still, with a wingspan of 212 feet, a length of 112 feet and a height almost 43 feet. On both aircraft, the wings were so large that crawl spaces were included that allowed engineers to service the engines from inside the wing while in flight. And it would take a whole lot of engine to power these behemoths. Boeing had wanted to use Allison V-3420 liquid cooled engines for the XB-15, but those were not available at the time, so they substituted Pratt & Whitney R-1830 radials instead. The difference in performance was stark, and the XB-15 could only manage 197 mph when empty. Fully loaded with 2000 pounds of bombs, it could only manage a feeble 145 mph. They did, however, hit the range target, managing 5,13o miles. The XB-19, coming later, would make use of the more powerful Allison engines, and it managed a somewhat better 265 mph, but still cruised at only 165 mph when loaded. And while it was a bit faster, it could not match the range of the XB-15, managing (only) 4,2oo miles.
Despite the disappointing performance, the XB-15 did make some historic flights, setting a load-to-altitude record in 1939 when it carried a 31,205 pound load to 8,200 feet, proving that while the plane wasn’t particularly fast, it could carry a very heavy load for its day. Following more record setting flights, and some bombing tests with meagre results, the XB-15 was converted to cargo/passenger duty and renamed the XC-105. But after proving difficult to fly and maintain, and suffering some in-flight fires, the XB-15 was unceremoniously scrapped in Panama in 1945. Stripped of its engines, internals and vertical stabilizer, the fuselage was dumped in a swamp at Albrook Field in Panama, where it slowly sank out of sight, and where it remains to this day.
The XB-19 didn’t fare much better. Douglas never really wanted to build the giant bomber, but the Army wanted to use it for testing and convinced Douglas to build a single prototype. However, problems with its construction led to significant delays, and when the XB-19 finally took its first flight in 1941, it was just two months before the USAAC signed the development contract for the Northrop YB-35 and the Convair YB-36, a competition that would produce the first strategic bomber with truly global reach. Like its Boeing counterpart, the XB-19 finished its days as a cargo and passenger aircraft. On its retirement, the Air Force wanted to preserve the giant bomber, but there was no program in place to do so, nor was there any place to display it. The XB-19 was ultimately scrapped in 1949, though two of its enormous tires were saved. One is displayed at the Hill Aerospace Museum at Hill AFB in Utah, and the other can be seen at the National Museum of the Air Force in Dayton, Ohio.
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