Previous Model Series B-50A
An increase in gross weight, from 168,480 to 170,400 pounds, a new type of fuel cell, and a few minor improvements were the basic differences between the B-50B and the preceding B-50A. The B-50B, however, was immediately reconfigured for the reconnaissance role. In this capacity, the RB-50B featured 4 camera stations (numbering a total of 9 cameras), weather reconnaissance instruments, and extra crew members housed in a capsule that was located in the aircraft's rear bomb bay. In addition, the RB-50B carried fittings for two 700-US. gallon underwing fuel tanks.
The Air Force had planned to use its next lot of 45 B-50s as atomic carriers. It also expected that the forthcoming aircraft, identified as B-50Bs, would be capable of carrying both the Mark 3 and Mark 4 bombs. However, neither plans nor expectations materialized. Indeed, besides the 45 non-atomic capable B-50Bs, 35 subsequent B-50 models would also fail to incorporate from the start the B-50A's initial post-production improvements. Meanwhile, the older RB-29's deficiencies in speed, range, and altitude prompted the Air Force to endorse the immediate reconfiguration of its 45 new B-50Bs. The decision did not reflect the Air Force's preferences. Ideally, reconnaissance aircraft should be superior in performance to the bomber type dependent upon their information. But limited funds had not permitted the development of such a specialized aircraft, and the proposed RB-36B remained a long way off. Acquisition of the RB-50B, therefore, appeared to be the best as well as the only alternative. Although all 45 aircraft were re-fitted for the reconnaissance role, the Air Force's financial ledgers kept on carrying the planes as B-50Bs.
The first B-50B, initially flown early in January 1949, was accepted by the Air Force on the 18th. Within a short period, 14 B-50Bs were delivered to SAC, the first of the 14 being received by the command on 31 January. This aircraft (Serial No. 47-119) was immediately sent to the Boeing Wichita plant for modification as reconnaissance aircraft, marking the beginning of the B-50B fleet's reconfiguration.
Adapting the B-50B to the reconnaissance role became a fairly involved project for a number of reasons. At first, the Air Force thought of exempting 15 B-50Bs from the proposed modifications. Then, because of new requirements, the Air Force decided to reconfigure all the B-50Bs and further, to fit them for a variety of reconnaissance purposes. Eventually, 3 different types of reconnaissance B-50Bs came into being. Although identified from the start as RB-50Es, RB-50Fs, and RB-50Gs, the reconfigured B-50Bs were not formally redesignated until 16 April 1951.
The RB-50E, first of the 3 types, was returned from the Wichita plant in May 1950. The Air Force acquired 14 RB-50Es, all of them in just a few months. Earmarked for photographic reconnaissance and observation missions, the RB-50E normally required a crew of 10. According to the type of mission being flown, the left-side gunner served as weather observer, or as in-flight refueling operator. When at this station, at altitudes above 10,000 feet, the left gunner had to use oxygen and wear heated clothing. As in the case of the original B-29,31 compartments for the other crew members were pressurized and featured heating and ventilating equipment. The RB-50E's defensive armament, like that of other B-50 models, also dated back to the B-29. The only difference was that the number of .50 caliber machine guns had been increased from 10 to 13, all of which were still housed in 5 electrically operated turrets. The turrets were controlled remotely from the sighting stations.
The RB-50F, the second reconfigured version, was returned from Wichita in July 1950. The Air Force received 14 RB-50Fs, Boeing completing the required modifications in January 1951. The RB-50F closely resembled the RB-50E, but was equipped with the Shoran32 radar system for the specific purpose of conducting mapping, charting, and geodetic surveys. However, the Shoran radar prevented the RB-50F from making use of its defensive armament, which was identical to that of the RB-50E. To give the weapon system additional versatility, the Shoran radar and associated components were housed in removable kits. Deletion of the kits and a simple adjustment restored the RB-50F's defensive power. Therefore, if needed, the 2 aircraft types could be used for the same basic reconnaissance missions.
The RB-50G, the third and last reconnaissance version derived from the B-5011, entered SAC's inventory between June and October 1951. The 15 reconfigured aircraft (Manufacturer's Model 345-30-25) differed significantly from the RB-50E and RB-50F Electronic reconnaissance was the principal mission of the RB-50G. The aircraft featured 6 electronic countermeasures stations, an addition which had necessitated a number of internal structural changes. Some external modifications had also been necessary to accommodate the radomes and antennae of the aircraft's new radar equipment. Finally, during the reconfiguration process, the 16-crew member RB-50G had been fitted with the improved nose of the B-50D, the production model which actually followed the B-50B. In contrast to the RB-50F, the RB-50G could use its defensive armament while operating its new radars and electronic countermeasures equipment.
Reconfiguration of the RB-50s did not necessarily eliminate some of the B-model's flaws. As a result, several modifications were accomplished either before, during, or after the basic aircraft had been adapted to the reconnaissance role. Problems of various importance were identified, some of them as soon as the aircraft reentered the Boeing plant. Leaks from fuel cells were an unexpected dilemma-probably attributable to the aircraft's thin, light-weight fuel cells . The B-50A, equipped with heavyweight fuel cells, had not encountered such difficulties. While AMC wrestled with the problem, interim measures were taken, including the tightening of cell interconnect bolts and replacement of defective tanks. In October, instead of improving, the fuel cell problem became worse, "a considerable increase in fuel tanks leaks [being] attributed to the arrival of cool weather." By year's end, AMC decided to replace the defective cells of the B-50B and all subsequent B-50s with a new type of fuel cell, as soon as it became available. Meanwhile, there were other problems. Like the previous B-50As, the new aircraft experienced fuel tank overflows, leaks in fuel check valves, failures of the engine turbochargers, warped turbos and warped turbo bucket wheels, generator defects, and the like. In addition, since all B-50 airframes were basically alike, the B/RB-50s shared the B-50A's trailing wing problems. This was not a new experience. Several years before, cracks had also appeared in the metal skin at both forward and trailing edge of the upper side of the B-29's wing assembly. In all cases, stress beyond metal strength had been the most probable cause. The permanent solution, finally endorsed in 1949, was to use heavier metal in the fabrication of future wing flaps. This was a simple enough solution, but not quickly implemented.
Cancellation of the B-50 program was not seriously considered before the aircraft entered the inventory in substantial numbers, but the program was drastically altered in 1949. An early B-50A, set aside to serve as prototype for the model due to follow the B-50B, did not fare well. Initially known as the YB-50C, this aircraft was expected to feature a longer fuselage, a single bomb bay, larger wings, and 4 new R-4360-43 turbocompound engines. The YB-SOC's take-off weight was tentatively set at 207,000 pounds, a significant 50,000-pound increase over the weight of most B-50 models. By November 1948, the B-50C mockup had been completed, inspection of the prototype was scheduled for May 1949, and 43 production aircraft (14 B-50C and 29 RB-50Cs) were already on order. In late 1948, because of the many changes embodied in its design, the future B-50C became the B-54, the original quantity of aircraft under contract remaining unchanged. The new designation, however, did not help the aircraft's prospects.
President Truman's curtailment of the fiscal year 1949 defense budget forced the Air Force to make some difficult adjustments. While the B-54's high price was known, the cost effectiveness of the aircraft was not clear. Yet for good reasons, neither Secretary of the Air Force W. Stuart Symington nor General Vandenberg wished to give up the new aircraft. No B-54s had been produced, but work was underway by the manufacturer and subcontractors. Therefore, the program's cancellation would entail some financial loss and disturb the industry. On the other hand, certain facts could not be overlooked. Whether known as B-50C or B-54, the aircraft had no growth potential; its design represented Boeing's effort to extract the last ounce of performance out of the final development of the basic B-29. Actually, the B-54 configuration provided an undesirable outrigger landing gear requiring wider taxiways than existed at operating bases; jet engines could not be added without designing entirely new wings; and the new K-1 bombing system could not be installed without sacrificing a belly turret or without a drastic alteration of the aircraft's fuselage. Finally, and of great importance, General LeMay39 wanted no part of the B-54.
On 21 February 1949, while appearing before the Board of Senior Officers, General LeMay again strongly reiterated that the B-54 program should be canceled in favor of additional B-36s, since development of the B-36 with jet pods indicated superior performance in speed, altitude, and range. Pending quantity production of the B-52, the SAC Commander stated, the B-36 provided the best capability to carry out his command's primary mission, a mission vital to national security.
Although Secretary Symington and General Vandenberg did not question General LeMay's expertise, both remained reluctant to terminate the procurement of the B-54. The crux of the problem was that canceling the B-54s and getting more B-36s would alter the medium/heavy bomber group-combination, included in the program recently approved by the Joint Chiefs of Staff. As an alternative, Secretary Symington then suggested substituting less costly B-50s for the B-54s. But the SAC Commander quickly pointed out that the substitution, even if acceptable on the basis of economy, would still be a very bad solution. Instead, General LeMay testified, if all programmed B-54s could not be replaced by B-36s, the best course of action would be to secure extra B-47s, as soon as possible. After weighing and balancing all factors involved, the Board of Senior Officers concluded that production of the B-47 should be accelerated, and additional B-36s bought. The board's recommendations were approved by Mr. Symington and General Vandenberg in April 1949, marking the end of the B-54 program.
The B-50B production ended in April 1949, with the delivery of 7 aircraft.
The RB-50s began leaving SAC's operational inventory in 1954, when modern but still troublesome RB-47s finally became available. SAC had 40 RB-50s in 1951, a peak total reduced to 12 in 1954 and 1955, with the last aircraft leaving the command in December 1956. However, in contrast to the B-50A, phaseout from SAC did not signify the end of the RB-50's primary role. In 1954, although reassigned from the command, several RB-50s, their Shoran equipment greatly improved, still performed photo-mapping missions; in 1957, a few RB-50Es and RB-50Gs continued to be utilized by the Air Force Security Service. However, these were exceptional cases, and the RB-50's primary career came to a close before the end of the decade.
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