Not at posted coordinates! Be sure to check the logbook for the bonus codes!
The saga of the BUFF begins in 1945. America had won WWII, demobilized nearly completely, and wanted a big bomber. The Pacific theater demonstrated the need for a long range, heavy capacity bomber that could make long range sorties with an significant bomb load. The B-29 in the war could do that, but was limited in speed. The Army Air Corps wanted a faster, higher service ceiling capability, so on 23 November, 1945 it issued Military Characteristics for Heavy Bombardment Aircraft. It specified max airspeed at least 450 MPH, 40,000 feet ceiling, 5,000-mile combat radius with a 10,000 lb bomb, and an enormous 80,000 lb bomb load, with accommodations for a 6-man crew plus a full relief crew. The normal acquisition process then began, consisting of Requests for Proposals (RFP), manufacturer submissions of design and cost quotes for the RFP, issuance of contracts to develop the prototypes, mock-ups, testing data and other preliminary (before production) steps.
In April 1946, Boeing Aircraft Co, Glenn L. Martin Co and Consolidated-Vultee Aircraft Corp. (later Convair) all submitted designs to compete for the RFP contracts. Boeing’s proposal was an aircraft heavier than the gigantic B-36 (yet to make its first flight as of the date when the proposals were submitted), also with six propeller-driven engines and a 3,570-mile operating radius, under the minimum of 5,000 miles. Martin and Convair designs were smaller, and the Martin operating radius was well under the specification. Convair’s was also less, but higher than Martin’s. All were turboprop engines.
By 23 May 1946, the Army Air Force (AAF) recommended Boeing’s design be selected, and a week later, the development contract was issued. The first week of June, Air Materiel Command (AMC) notified Boeing it had won the competition. On 14 June 1946, the AAF designated the heavy bombardment aircraft the XB-52.
The XB-52 came under intense fire due to its similarity to the B-36, and its seemingly “unrealistic” size. At the time, the top brass (general officers in the AAF) wanted jets as enemy fighter technology was advancing too fast for propeller bombers. The XB-52 either needed to fly faster and farther, or it had to carry a lot of extra (heavy) defensive guns. In aircraft, weight costs speed and range. The aircraft was under a lot of criticism for its substandard performance and range. In January 1947, after the AAF requested Boeing study a “special weapons” bomber with the 5,000-mile range and at least 400 MPH cruise speed, Boeing submitted designs for two propeller-driven bombers: the Model 464-16 and 464-17. The former was a monster, at 480,000 lbs max gross weight, and combat radius of 5,100 miles and a 10,000 lb nuclear bomb in the belly. The latter was smaller, at only 400,000 lbs gross weight and a staggering 90,000 lb bomb load, but could only carry it 1,950 miles combat radius. At the conference where the two designs were assessed, the powers-that-be selected the 464-17, and the Boeing contract was amended to match.
In March of 1947, aircraft engine manufacturer Pratt & Whitney started to develop what they called the JT3-6 Turbojet engine; it would eventually be developed into the J57 jet engine. While this occurred, the Model 464-17 was still being designed with turboprop engines. By 26 July, the War Department, and AAF were superseded by the Department of Defense, and the creation of the US Air Force (itself becoming a new service on 18 September 1947). Tensions remained high for a bomber that checked all the proverbial boxes, but was still not jet-powered. On the first day of December, another conference with the top brass considered giving the XB-52 the axe as it was too slow for enemy fighters. On 8 December, they then issued updated military characteristics for the XB-52: cruise speed was now 500+ MPH, range down to 8,000 miles, and deleted a gross weight limit. Now the airplane had to meet certain takeoff and landing runway maximum lengths over a 50-foot-tall obstacle (9,000 feet for each). In addition, only the tail would have defensive armament, and capability for aerial refueling was required. Three days later, a 3-star general in HQ Air Force ordered AMC to cancel the Boeing XB-52 contract to allow other manufacturers to compete for the contract.
Since the size of the XB-52 was determined by the enormous size of the stockpiled atomic bombs of the late 1940s, the president of Boeing and the Commander of AMC argued against the cancellation of the contract, contending that the Atomic Energy Commission (AEC) was redesigning the atomic bombs, and Boeing’s work could save the government money by doing the studies on making the aircraft suitable to carry the bomb when it was finalized. Other points in the protest seemed to have sufficient weight that the cancellation was reversed on the last day of 1947. On 7 January 1948, the new design requirements were provided to Boeing. Boeing dubbed its design of an aircraft to meet the new requirements the Model 464-35, and depended on aerial refueling to reach the range requirements.
At that time, the only deployed air refueling method was a probe and drogue hose system developed by the British. The system was slow to transfer fuel (200 gallons/minute) and the refueling aircraft as well as the receiver required an operator to manage the fuel transfer. Finally, the refueling aircraft then used were slow (200 MPH). Boeing was already developing the flying boom system, which was easier to connect between aircraft, transferred 250% more fuel than the rate of the probe and drogue hose system, and only the tanker aircraft required an operator to transfer fuel. In September 1948, the flying boom refueling equipment successfully completed flight tests.
On December 17, 1947, the XB-47 jet bomber made its first flight. It was powered by six turbojet engines, and the engine pairs in pods seemed to impress the test pilot. Jet propulsion was the wave of the future, but Boeing still hadn’t committed it to the XB-52 yet. The YB-49, an experimental jet-powered flying wing (similar to the B-2 Sprit bomber today—no tail) also first flew in October 1947, and its jet propulsion delivered the speed the AF wanted. Although impressive, 1940s technology was not up to the task of managing the instability of a flying wing, and human pilots would fatigue quickly attempting to make the continuous control inputs to maintain flight. When the second YB-49 crashed due to instability, the idea was scrapped for decades.
On 3 March 1948, the AF again updated the design requirements for the XB-52: Max speed: 550+ MPH desired, 500+ MPH required; 45,000 feet ceiling desired, 40,000 feet required, and a requirement for a 20,000-foot ceiling with half of the engines running. Range was revised as well, 9,500 miles with a 4,000-mile operational radius. The obstacle takeoff and landing requirements also revised to 6,500-feet desired, 9,000-feet required, and raised the average bomb load to 15,000 lbs. The cockpit crew would be tandem-seated as in the XB-47, which boosted visibility and aerodynamics for the aircraft. Boeing’s Model 464-35 design proposal was submitted on 20 April 1948 for manufacture, delivery and flight tests for two aircraft. In May 1948, AMC asked Boeing to consider using Westinghouse XJ-40 jet engines. There were fundamental issues with pushing propeller and turboprop engines to this extreme—the jet engine had been in development since 1941, and the XJ-40 was the most powerful known in the US at that time. Boeing’s answer to the request was design Model 464-40, with eight XJ-40 jet engines. It was expected to have a 536 MPH top speed, and increased 45,200 feet ceiling, but reduced range over the -35 model.
In global news, on 24 June 1948 the Soviet Union blockaded Berlin, Germany and the AF thereafter began its Berlin Airlift to ferry supplies to keep the Berliners from starving. The AF began to understand the need for bomber aircraft, and to understand its role in protecting freedom for its allies and partners globally. Three years after the second combat use of the atomic bomb, the AF only had one unit of B-29s that could deliver it (See Feelin’ BUFF 44: Key B-52 Wings: 509th Bombardment Wing, Pease AFB, NH). The first production all-turboprop B-36As reached Carswell AFB, Texas (See Feelin’ BUFF 46: Key B-52 Wings: 7th Bombardment Wing at Carswell AFB), by the end of June, although they were used only for training. The AF still had no jet atomic bomber, although by October 1948 the B-36D was approved for its addition of four General Electric J47 jet engines. Even with jet engines, the B-36D couldn’t compete with the XB-52 in ceiling, operating radius or speed.
In October of 1948, a couple of developments would change BUFF history forever. On the 16th, one AMC general complained that the turboprop XB-52 would not be able to evolve into a capable bomber. On the 21st, some Boeing personnel (the project engineer, an aerodynamicist and Chief of aerodynamics) met with AMC at Wright Field (later Wright-Patterson AFB, Ohio); AMC’s concern was that the XB-52 was an insufficient improvement over the lumbering B-36 to warrant spending the vast sums of money on its development. On the 22nd, the Boeing officials met with their Vice President of Engineering and two other engineers in their hotel room to thoughtfully discuss the jet-powered option.
They worked into the weekend to meld what they knew from the XB-47 program and the variable ratio thickness (thick at wing root and thin at wingtip) wings from the design of the XB-55 (medium bomber to replace the B-47—cancelled in January 1949). The swept wing of the XB-47 was applied to the XB-52 at 35 degrees, and the redesigned “second generation swept wing” could hold fuel to increase range. To the revolutionary new wings, they added the XJ-40 jet engine, and a relatively-unknown Pratt & Whitney jet engine, the JT3 (later J57), due to its higher thrust and lower fuel consumption. The new wing and engine combo promised a 49,000-foot ceiling at 520 MPH cruise speed and max speed of 572 MPH. The 25th of October arrived with a Boeing proposal for the Model 464-49 with JT3 turbojets. The most important redesign of the XB-52 began in a hotel room!
On 17 November 1948, Boeing received an agreement to build two Model 464-35 (the turboprop version) aircraft. Propellers then could hardly withstand 300 MPH operation much less 500+ MPH. Maintenance was far more intensive on turboprop engines and vibration demanded heavier/thicker airframe structures. Turbojet engines could fly faster and higher. In the AF’s view, jets were the only way to go. In late January 1949, the AF approved the Model 464-49 and allowed Boeing to develop the turbojet design, without going to a new design competition (due to the model closely meeting design requirements). On 10 March 1949, AMC amended the agreement for experimental aircraft under Model 464-49 (phase 2 version dubbed 464-54). In late April 1949, Boeing hosted a mockup evaluation of the jet version of the XB-52, the Model 464-54. In June, Pratt & Whitney received a supplemental agreement to build two XJ57-P-1 engines for testing, including modifying a B-50 aircraft on which to test them. Bicycle-style landing gear like that used on the XB-47 was changed on the XB-52 to quadricycle landing gear, with wing tip gear. This eliminated the need for a bomb loading pit and increased clearance.
On 29 August 1949, America’s monopoly on the atomic bomb ended, as the Soviet Union detonated their own copy of the Fat Man (implosion) bomb, shamelessly stolen from Manhattan Project engineers by their own spies. The need for an intercontinental, jet bomber to deliver the atomic bomb was as grave as ever! The Soviet test also hastened development of the “super” or hydrogen (thermonuclear) bomb in America.
Also in August, Pratt & Whitney’s (P&W) J57-P-1 was redesigned to be more efficient and lighter, so it was dubbed the J57-P-3. Throughout the Fall of 1949, various reviews continually threatened the XB-52 as a whole—the range wasn’t meeting requirements, and could have the project axed altogether. Reopening the competition to regain the lost range was considered, as the range minimum might not be reached by 1956/57. General Curtis Lemay (the commander of Strategic Air Command) revectored AMC’s effort regarding range—speed loss to regain range was unacceptable. The J57 would have priority over all other jet engine development to regain efficiency/range. On 8 March 1951 and mounted to the B-50 bomber, the experimental J57 engine made its first flight. Three months later, Boeing received the first prototypes.
AMC would not authorize production until the XB-52 could meet range requirements; more threats of cancellation loomed. In mid-December, AMC was ordered to study using B-47s with aerial refueling to meet the mission of the XB-52—one B-47 would need three tankers, vast numbers of aircrew and maintenance personnel plus fuel and the cost would exceed $100 million MORE than the XB-52 program, which helped save the program (again!).
In November 1949, Boeing proposed Model 464-67 with 4,313-mile radius for 1953 production models and a 500-mile upgrade by 1957. General Lemay also directed SAC would only take delivery if the range be met WITHOUT aerial refueling, no loss in speed, and at least half a dozen test aircraft, as working the kinks out of a design could only be done by flying it. In early December, P&W received a contract to build 18 experimental YJ57-P-3 engines for testing. On 6 June 1950, the engine pod mockup was completed and evaluated—officials were finally confident the aircraft would meet range minimums. Later that month, 45% of the design of Model 464-67 was completed and some parts were fabricated.
On 9 January 1951, the XB-52 production program was launched by the AF. By February, 35% of the two experimental aircraft were built. Two weeks later, AMC issued a production contract for 13 B-52As to be delivered by April 1953. On 1-2 March, a mock-up meeting at Boeing led to major change recommendations—SAC’s commander, General Lemay wanted a side-by-side cockpit arrangement (although SAC had requested tandem during designing), added 3 crew members into the forward fuselage and changed the hydraulic system to electrical—essentially changing the airplane design entirely. By May, the design changes were made, another mockup inspection occurred, and on 13 June 1951, the second XB-52 prototype was designated YB-52, and carried serial number 49-231. The first XB-52, Model 464-67 carried serial number 49-230. On 29 November 1951, amid strict secrecy and covered with tarps, XB-52 49-230 rolled out of the Boeing assembly hangar for the first time. On 15 March 1952, YB-52 49-231 rolled out of the Boeing factory. It flew for the first time with the experimental J57 engines on 15 April 1952; its stablemate, 49-230 had a maintenance problem that caused a pneumatic system explosion that damaged the wing and prevented its first flight until 2 October 1952. Formal contracts for production were received at Boeing on 16 December 1952 and revised quantities to 3 B-52As and 17 B-52Bs.
The XB-52 survived numerous threats of cancellation, competition by multiple designs, experimental, unproven engines, a myriad of changes and redesigns, and eventually became a production model. The saga of the XB-52 ends here, but the BUFF would emerge from production in many variants, by the hundreds, to populate dozens of SAC wings across the planet. Stay with us as we explore each version and so much more!
To find this cache, calculate the coordinates from the information in this listing.
N 48° 20.ABC W 101° 17.DEF
A= Minimum airspeed, per on 23 November 1945 Military Characteristics, NXX MPH A=(N)
B= Later name of JT3 Pratt & Whitney jet engine, J-XN, B=(N)
C= Year the experimental J57 engine made its first flight mounted to a B-50, XXNX, C=(N)
D= Designation of November 1949 Boeing proposal with 4,313-mile radius, Model 464-NX, D=(N/2)
E= Serial number of first XB-52, Model 464-67, serial number 49-XXN, E=(N)
F= 16 December 1952 revised quantities for production B-52As, N quantity, F=(N)
Tagg, L. (2004). Development of the B-52: The Wright Field Story. History Office, Aeronautical Systems Center, AFMC: Wright-Patterson AFB, Ohio.