Staff Writer (Updated: 4/13/2016):
The Boeing firm had made a name for itself beginning with its aircraft developments throughout the interwar years following World War 1. By World War 2, the company would become a household name thanks to its development of the stellar B-17 "Flying Fortress", serving in both the Pacific and European Theaters, as well as its follow-up design - the B-29 "Superfortress" long range, high-altitude heavy bomber charged with dropping the two atomic bombs on Japan. The commercial "Stratocruiser" appeared in the post-war years as did the military B-47 "Stratojet" bomber. It was no surprise then that the designation of "Stratofortress" was selected for what would become one of the Boeing's biggest successes to date.
Origins of the B-52 stemmed from a specification issued through the forward-looking Air Material Command (AMC) on November 23rd, 1945. AMC fell under the branch of the United States Air Force at the end of World War 2 though it originally began service in 1917 as part of the US Army Signal Corps. This new specification called for a next generation long-range, intercontinental, high-altitude strategic bomber to replace the already-in-development Convair B-36 Peacemakers. In February of 1946, the Boeing Aircraft Company, Consolidated Aircraft Corporation and the Glenn L. Martin Company all jumped into the fray with their respective responses. Boeing's team devised the Model 462 as a straight-wing, multi-engine design powered by 6 x Wright T35 Typhoon turboprop engines rated at 5,500shp each. On June 5th, 1946, Model 462 was selected ahead of the pack and the legacy of the B-52 was born in the designation of XB-52. A full-scale mockup contract was then awarded.
By now, the USAAF (United States Army Air Forces) was already looking beyond the qualities of the Model 462, fearing that the aircraft was already rendered obsolete in its conventional design approach and could never reach the intended goals of the original specification - especially in terms of its range. As such, the USAAF cancelled their contract with Boeing and the Model 462 was dead.
Boeing chief engineer Ed Wells took the Model 462 and evolved a pair of smaller concepts with four turboprops each appearing in their respective 464-16 and 464-17 forms. Essentially, the 464-16 was a short-range bomber made to carry a greater bombload while the 464-17 was a long-range bomber made to carry a smaller bombload. Neither idea stuck with the USAAF as a replacement for the B-36 though interest did center on the 464-17 design. Several more concepts were developed but interest on the part of the Air Force was waning. The Model 464-29 appeared, complete with swept-back wings at 20 degrees and fitting 4 x Pratt & Whitney turboprop engines. Again, this concept failed to answer the key points of the specification which, by now, was ever-changing to include increased performance specs along with long range.
The Model 464-35 was another Boeing design team proposal fitting 4 x turboprop engines with contra-rotating propellers. Wing sweep was increased moreso than previous attempts, beginning to define the look of the Stratofortress. With in-flight refueling becoming more of a USAF operational norm, the design team now had some leeway in the overall size of their aircraft. Events in Europe in the latter part of the 1940's pushed the XB-52 project forward, rewarding the Boeing Company with a hard-earned contract for a single mock-up and at least two flyable prototypes.
Upon a visit to Wright-Patterson AFB by the Boeing design team, it was learned that the USSAF was now more interested in a jet-powered solution, seeing it as the only way to achieve the desired performance specs it required of the XB-52. In the course of a single weekend in a Dayton hotel room Ed Wells company set to work on new ideas for a Monday morning presentation. The resulting design combined elements of their Model 464-35 design with a four-engine, jet-powered medium bomber concept that had been brought along. The new aircraft became an eight-engine, Pratt & Whitney JT3 jet-powered heavy bomber with 35-degree swept wings. A small balsa wood model was constructed to further develop the idea and accompanied a detailed Model 464-49 design document of some 33 pages. The weekend effort paid off for Boeing as the USAF became greatly interested in the aircraft after Monday morning. The design was revised into the Model 464-67 accepted the new aircraft for construction as two prototypes. Despite this progress, the USAF was still looking at alternatives to their next generation bomber design including modifying B-36's (as the YB-60) and B-47's (as the B-47Z) still in development.