Aviation Ancestry - July 2011
Buff: Part 1
By Scott Schwartz
The XB-52 had the pilot and co-pilot sitting in tandem, under a fighter-like canopy. Then-SAC Commander Gen. Curtis LeMay objected to this arrangement, and production models had side-by-side seating for the pilots. (Photo courtesy of the National Museum of the United States Air Force)With a wary eye on Nazi aggression, the U.S. was in need of a bomber that could fly directly to targets in Europe from bases on the North American continent. This was the early 1940s, and several long-range bomber programs were launched. None came to fruition until just after the end of the war, when Convair rolled out its piston-engine XB-36, and Northrop presented its XB-35, which was also powered by piston engines. Nevertheless, the U.S. Army Force had already set its sights on more modern, post-war designs as early as 1945. By the end of that year, the desired specifications for a high-speed/high altitude bomber had coalesced into an official requirement. The new bomber had to be able to carry ten thousand pounds of bombs, be able to carry those bombs for 5,000 miles, and it had to cruise at 300 mph while flying at 35,000 feet. At the time, the new Consolidated-Vultee B-36 could fly high and far, but not fast enough.
In response to this new bomber requirement, Consolidated-Vultee came up with an aircraft that was basically a swept-wing, jet engine version of the B-36. Boeing’s design – the Model 462 looked suspiciously like the B-29. And, with good reason; the Model 462 was essentially a scaled-up version of the B-29/B-50 Superfortress.
The difference, though, was that the Model 462 was to be powered by six Wright T35 turbo-prop engines. Although the Model 462 initially met most of the Army’s requirements, its projected top speed wasn’t great enough, so more powerful turbo-prop engines were figured into the mix. Plus, the wings changed so that the leading edges were slightly swept back. The end result was a descendant of the B-29/B-50 with swept wings and six turbo-prop engines that drove contra-rotating propellers. The new U.S. Air Force authorized construction of two prototypes plus one mock-up of the new bomber, which was now designated as the……B-52.
The B-52 that we know today would have turned out quite differently, had it not been for three things. Item number one was the successful development of the swept-wing XB-47 jet powered medium all-jet bomber. Item number two was the mechanical problems that were being encountered with the turbo-prop engines. Not to mention the fact that the turbo-prop design would have yielded performance that was only marginally superior to that of the B-36. Item number three was the development of an air-to-air refueling system that actually worked.
Not surprisingly, Boeing engineers wanted to revise the XB-52 design.
During an October, 1948 meeting between Boeing engineers and Air Force Colonel Pete Warden (who was in charge of the new bomber program), Warden went further than merely agreeing with the engineers’ request to make changes. Warden actually suggested that a new jet engine – the Pratt & Whitney J57- be considered for use in the XB-52. He also recommended that the wings be swept back at a 35-degree angle, instead of the 20-degree sweep that was being suggested by the Boeing engineers.
Since the meeting was held on a Friday, the engineers were able to revise the XB-52 design over the following weekend. One of them even built a balsa-wood model of the new design
The model was shown to Col. Warden on Monday morning; he was pleased with the changes and approved the revised design.
With power provided by eight of the new Pratt & Whitney YJ-57 engines, the aircraft had a wing span of 185 feet and was expected to weigh 152,300 pounds- empty.
Like the B-47, the XB-52’s main landing gear was placed in the fuselage, and there were “out-rigger” wheels mounted in the wing tips. However, all four of the XB-52’s main landing gear were steerable for cross-wind compensation.
With a projected average cruise speed of 453 mph, the XB-52 was expected to have a combat range of 5,270 miles at that speed. Top speed was expected to be 538 mph at 20,000 feet.
Although the XB-52 design had been revised numerous times during its evolution – resembling at times, its B-17, B-29, and B-50 forerunners, the aircraft that emerged from the Boeing plant on November 19, 1951, was a swept-wing, turbo-jet powered, modern-looking beauty. Its modern appearance was only slightly marred by the framed cockpit canopy that covered the pilot and co-pilot in tandem.
Naturally, an exhaustive-series of tests had to be performed on the ground before the XB-52 could be flown. At one point during the testing, a hydraulic explosion blew the trailing edge off one of its wings. The needed repairs kept the XB-52 grounded until October 2, 1952, while the second prototype- the YB-52- actually flew first - in April of that same year.
As with any new airplane, a few bugs had to be ironed out of the new airplane. After both prototypes had been flown, the biggest complaint seemed to be that the airplane was “heavy on the controls” and that it “handled like a truck.” More work was done, and this problem was corrected.
Overall, the Air Force was quite pleased, at this point. The new airplane (now called “Stratofortress” in honor of its famous “Fortress” predecessors) proved to be extremely fast for a heavy bomber. In fact, the YB-52 averaged 624 mph on a record-flight between Seattle, Washington and Dayton, Ohio in September, 1954. This, by the way, was actually a higher speed than the one attained by the F-86 Sabrejets which had made the same flight earlier that same year.
The then-commander of the Strategic Air Command, General Curtis LeMay, had only one issue with the X/YB-52. A former B-29 pilot himself, LeMay wanted the pilot and co-pilot of the new bomber to sit side-by-side.
Boeing engineers complied and re-designed the cockpit. With that, the aircraft was cleared by the Air Force for production.
