Bomber, Long Range: The XBLR Aircraft

"ttyymmnn" (ttyymmnn) 10/15/2015 at 12:35 • Filed to: planelopnik, planelopnik history, Planes you've (probably) never heard of, wingspan

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From the Planes You’ve (Probably) Never Heard Of Department of Wingspan, we bring you the Boeing XB-15 and Douglas XB-19.

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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 XB-15 (US Air Force)

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.

Douglas XB-19 (US Air Force)

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.

A publicity shot showing just how many dancing girls and their dates can fit on the wing of the XB-15 (US Air Force)

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.

XB-19 at March Field in California (US Air Force)

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 !!!error: Indecipherable SUB-paragraph formatting!!! and the !!!error: Indecipherable SUB-paragraph formatting!!! , 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.

XB-19 tire, with suitably impressed young woman for scale. (US Air Force)

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For more stories about aviation, aviation history, aviators and airplane oddities, visit !!!error: Indecipherable SUB-paragraph formatting!!! .

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T5Killer > ttyymmnn 10/15/2015 at 12:50

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Love it. The XB-15 and -19 I only recently found out about and I thought I was versed in US military aviation of the era. Great write up keep them coming.

ttyymmnn > T5Killer 10/15/2015 at 12:55

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Thanks! I had read, but forgotten, about the XB-15, and it popped up again during the course of writing my regular Aviation History posts. It took its first flight on this date in 1937. I was going to write about it, but then decided it worked better to lump these two together. I had never heard of the XB-19. This one was fun to write.

HammerheadFistpunch > ttyymmnn 10/15/2015 at 13:05

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This tire?

Man that was a long time ago.

ttyymmnn > HammerheadFistpunch 10/15/2015 at 13:08

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That would be it. And, that would be you?

HammerheadFistpunch > ttyymmnn 10/15/2015 at 13:08

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many moons ago, yes.

ttyymmnn > HammerheadFistpunch 10/15/2015 at 13:16

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I trust you’ve gotten a haircut since then.

HammerheadFistpunch > ttyymmnn 10/15/2015 at 13:18

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at least one.

sunnydaysam > ttyymmnn 10/15/2015 at 13:31

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ah, the dreaded ‘dancing girls and their dates’ wing loading test.

thanks for another great post ttyymmnn. I look forward to every one.

ttyymmnn > sunnydaysam 10/15/2015 at 13:35

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Thanks for reading! I’m not certain, so I didn’t write it, but I think that is a shot from what was called the “Georgia Peach Run,” where they flew entertainers down to the Panama Canal Zone. The thing is, though, by that time the XB-15 had been dubbed “Grandpappy” (and, incidentally, it was one of the few aircraft that crews referred to as “he” rather than “she”) and painted in green Army camouflage. This photo is still in its factory aluminum. So I just couldn’t be sure about the timing. Nevertheless, it’s a pretty awesome picture. Now, designers just use rigs to test the wing stresses. How boring is that??

Viggen > ttyymmnn 10/15/2015 at 14:16

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Good quick read. Never seen a picture of the XB-19. Those tires are massive. Wonder how they compare to the single wheel bogey originally used on the B-36?

It’s important to note just how much the XB-15 influenced the design of the B-17.

ttyymmnn > Viggen 10/15/2015 at 14:44

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There is definitely a noticeable lineage from the Model 247 all the way through the B-17. It was really just a matter of scaling up a successful design.

Model 247

ttyymmnn > Viggen 10/15/2015 at 14:49

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Good quick read

Thanks. I think I’m finding the sweet spot on just how much people are willing to read. It’s a challenge to include just enough to be informative while not so much that folks stop reading.

Viggen > ttyymmnn 10/15/2015 at 14:50

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Oh yeah, for sure. Love the B-17. First aircraft I was able to say the name of. Probably one of my first words too.

Viggen > ttyymmnn 10/15/2015 at 14:55

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That’s the problem with our hobby of aviation. You either say a little, which causes misunderstanding or say too much and people stop reading.

If I tried that with the F-4 I’d be writing the latter, certainly. Actually reminds me I need to crack open my F-4J NATOPS manual.

ttyymmnn > Viggen 10/15/2015 at 15:07

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The trick is to find interesting facts that are unassailable, which usually requires checking multiple sources, and not writing another Wikipedia article. Nobody wants to read that much—including me!

Viggen > ttyymmnn 10/15/2015 at 15:11

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See I can spend all day reading about aviation. In fact, I do sometimes. But that’s not why I come to Oppo.

Grindintosecond > ttyymmnn 10/15/2015 at 17:48

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This is the bombload. Once having been dropped over enemy targets, all of these women and their escorts would elicit massive ‘hitting’ on the girls from the enemy where the servicemen would then begin punching the daylights out of anyone trying to ‘steal their dates’. Later they realized that a generally armed paratrooper was a better idea and they no longer needed that many girls in one mission. The paratroopers were ordered to ‘get over it.’