B-58 Development Problems
Approval of Convair's new design did not ease the Air Force's concern about the engine of the future aircraft. As summed up by General Partridge, every effort had to be made to safeguard the successful development of the J79 upon which the "vitally important B-58 and other projects will be so heavily dependent." The J79 turbojet became the world's first production Mach 2 engine. In addition to the B-58, it eventually powered the Lockheed F-104, the McDonnell F-4, and the North American Aviation A-5. Equally concerned, General Putt informed the General Electric Company that the J79 project controlled "to a very major degree, this country's ability to defend itself during the 1958-1965 period." "This responsibility;" General Putt wrote, "should not be treated lightly." The fact remained that the development histories of American and British turbojets showed that 4 to 5 years were needed from the beginning of design to completion of the 150-hour engine test. This was confirmed by the General Electric engineers, who insisted that delivery of the J79 engine could not be scheduled until July 1957. Based on experience, the Air Force thought this schedule might still be unrealistic. The solution therefore was to equip early B-58s with a version of the already tested Pratt and Whitney J57, but this temporary expedient also would pose problems.
This first development engineering inspection replaced the formal mockup inspection which, obviously, had been scheduled to occur too soon for major subsystems to be available (A second development engineering inspection took place on 29 September 1953. It covered portions of the RB-58 that differed from the B-58. Also held in Fort Worth, the inspection did not cover major subsystems, most of them still remaining a long way off). Nevertheless, except for the missing components (for which space was provided), the B-58 mockup was complete. Air Force inspectors, including representatives from SAC, were able to get a good idea of the new weapon system, by then known as Configuration II. The inspection group, and General LeMay in particular, asked for many changes, but none appeared vital. Just the same, as the inspection neared its end, General Boyd most likely expressed everyone's opinion in stating: "It is a radical design, and we must be careful in following through with these technical developments." He added, however, that Convair seemed to have done a very good job.
Military characteristics (No. 345) for the B-58 high-altitude bombardment system, at long last issued in September 1953, did not bring any great surprises. The requirements fairly matched the specifications proposed by Convair in August 1952, and the lesser USAF demands embodied in the September GOR of the same year: Yet the new characteristics required the carrying of payloads in addition to the warheads originally specified. While this requirement had been anticipated, it implied that greater performance standards would have to be achieved in order to preserve the aircraft's range, which was unchanged. The B-58 would carry 20,000 pounds of munitions, a 13,000-pound increase. This could be expected to entail a reduction of the aircraft's fuel load and, therefore, a significant loss of range. There were a few other changes, most of which stemmed from SAC's criticism. For instance, the side-by-side seating that General LeMay preferred to the tandem seating arrangement of most Air Force planes was not provided, but the B-58 would at least contain a jump seat (subsequently omitted, for lack of space) for one of the crew members to sit alongside of the pilot during take-off and landing. The new characteristics also included some concessions. Maximum dash speeds at altitudes of 55,000 feet were reduced slightly, and the B-58's operational date was postponed from 1957 to 1958 or later.
Much to the disappointment of ARDC, and despite application of the area rule, on-going wind tunnel tests of Configuration II continued to produce high-speed drag figures. Stability test results also caused concern. The elevons and rudder were not inherently balanced and depended on the rigidity of their actuating systems to prevent flutter. The engine positions and the anticipated Mach 2.1 speed similarly produced some qualms. In addition, as first identified by the development engineering inspection of August 1953, it had become obvious that the compartmented pod, housing the bomb and fuel, needed to be entirely redesigned. This was confirmed in October 1953, when the Air Force authorized Convair to shorten the B-58 pod and to sling it on a pylon under the fuselage. Finally, other changes had to be made to satisfy the anticipated new requirements of the September military characteristics. Meanwhile, other problems loomed ahead. Subsystem development, never considered to be easy, promised to be especially difficult in the B-58's case. As early as 1951, the Air Material Command strewed that it took much more time to design, develop, and produce new equipment such as guns, engines, and fire-control systems than it did to produce new airframes.
The future aircraft had already been acknowledged as a most complex, highly integrated, and mutually interdependent weapon system. The Air Force, consequently, kept a close watch on every component's progress. In December 1953, it asked for studies to determine if the Arma Company's A-3A Fire Control System could serve as a back-up for the Emerson Company's Active Defense System earmarked for the B-58. The Air Force also wanted to know if a modified M-2 Bombing System, built by the International Business Machine Corporation, could possibly substitute for the sophisticated Navigation-Bombing and Missile Guidance System, being developed by the Sperry Gyroscope Company. Aware of the state-ofthe-art's current and foreseeable limits, the Air Force attached great importance to the B-58's forthcoming bombing and navigation system. How a B-58 would find and hit its targets, given its speed and altitude design characteristics, was a difficult question to answer. Worrisome comparisons came to mind. For example, in order to obtain a 3-minute bomb run for a B-17 operating at 25,000 feet, the bombardier would have to get on his target about V miles away; in the same vein, with a B-58 operating at 40,000 feet at an airspeed of 450 knots, the bombardier would have to spot and track his target from at least 25 miles away. But to have a 3-minute bomb run at the B-58's designed speed of Mach 2 and at an altitude higher than 50,000 feet, the bombardier would have to be on target some 66 to 70 miles away. The problem was serious enough to justify organizing a special committee to monitor the development of B-58 bombing and navigation procedures. This committee consisted of representatives from the Air Staff, ARDC, SAC, Air Training Command, and the contractors. In early 1954, the B-58 Joint Project Office considered the adoption of the monitoring committee idea for other component systems as well.
Configuration III, as devised by Convair, did not fare as well as expected. The reconfigured B/RB-58 featured a new bomb and fuel pod that had been shortened from 89 feet to 30 feet, and was now detached from the fuselage and suspended on a pylon. Tb compensate for the smaller amount of fuel carried by the pod, external fuel tanks had been added to the wing tips. The search radar had also been removed from the pod and placed into the fuselage nose. There were other alterations and deletions. The droppable nose gear was eliminated, and the positions of the bombardiernavigator and the defensive systems operator were reversed. For lack of space, Configuration III omitted a jump seat, a new requirement of the military characteristics. In any case, the Air Force did not share Convair's confidence that the reconfigured B/RB-58 would achieve better performance. Early 1954 tests in the tunnels of the Wright Air Development Center and National Advisory Committee on Aeronautics soon confirmed that the contractor's estimates once again were wrong. In addition, a problem thought to be solved had reappeared. In 1953, the contractor and the Air Force had decided to abandon the previously endorsed split nacelle engine arrangement in favor of 2 strut-mounted Siamese nacelles. The change would save weight, ease engine maintenance, and facilitate retrofit of J57-powered aircraft with new J79s. Unknown to all at the time, this last advantage would have been of no value since the B-58 schedule slipped and production of the J79 engine caught up with the Convair program. Recent tests, however, indicated that Siamese nacelles induced extra drag on the composite (pod- or missilecarrying) B-58, although the airframe itself was affected almost equally by either type of nacelles. In practical terms, this meant a return to split nacelles, more testing, more delays, and postponement of the Configuration III's mockup inspection from the initially scheduled May date to September 1954.
Based on a preliminary review of the B/RB-58's third configuration, the Wright Air Development Center finally agreed on 4 December 1953 that Convair could begin the construction of airframe components. Yet, subsequent testing of Configuration III qualified this hopeful decision. In March, the B-58 program underwent a drastic change; research and development came to the fore at the expense of production, and the number of B-58s originally contemplated was reduced from 244 to 30, with the latter quota emphatically referred to as "test vehicles." Moreover, long lead time items such as ground training devices and maintenance and test equipment were cancelled. Secretary of the Air Force Harold E. Talbott approved the redirected program on 30 April 1954, and authorized release of the procurement funds necessary to support it (Secretary Talbott succeeded Thomas K. Finletter as Secretary of the Air Force on 4 February 1953. Mr. Finletter had replaced Mr. Symington, the first Secretary of the Air Force, on 24 April 1950). Yet, as illustrated by the June procurement directive that followed, the Air Force again qualified its authorization. The directive freed about $190 million of fiscal year 1955 money for 13 test aircraft, but no procurement of any kind could be initiated prior to determining a firm configuration. As it happened, these 13 aircraft were the only B-58s covered by the first definitive contract, at long last signed in December 1955. The remaining 17 test vehicles were carried on another procurement contract, finally initiated by a mid-1956 letter contract. Indicative of the uncertainties that surrounded the costly B-58 program, it took 5 definitive contracts to get less than half of the number of B-58s first ordered. Furthermore, most letter contracts ended with an unusually large number of supplements and amendments. The whole procedure eventually resulted in substantial amounts of termination costs.
Crucial events preceded Convair's achievement of its fourth B/RB-58 configuration. A development engineering inspection of Configuration III, held in mid-May, was a near fiasco. Not only did it endorse the poor results of past and concurrent wind tunnel tests, but SAC representatives insisted that the width of the configuration be altered to allow side-by-side seating of the pilot and the navigator-bombardier, a change considered totally impossible. But as the future of the B-58 appeared at its gloomiest, important research progressed. National Advisory Committee on Aeronautics aerodynamicist R. T. Jones at first had been mystified by the problems of airframes designed to the transonic area rule and tested at supersonic speeds. However, by the summer of 1954, he had ascertained that the position and the extent of the fuselage indentation was indicated by the aircraft's designed speed. This time, the Convair engineers did not question Jones' discovery. In August, Configuration III's fuselage was aligned to the modified transonic area rule for supersonic speeds (For a transonic body, the area rule is applied by subtracting from or adding to its cross-sectional area distribution normal to the airstream at various stations so as to make its cross-sectional area distribution approach that of an ideal body of minimum drag; for a supersonic body, the sectional areas are frontal projections of areas intercepted by planes inclined at the Mach angle).
Officially referred to as the B/RB-58A configuration, the new design featured other innovations. External wing fuel tanks were eliminated, the tail area was extended to 160 square feet, and the 4 engines were suspended by separate pylons, 2 under each wing. Convair was sure that the new B/RB-58A configuration would satisfy the performance requirements of the military characteristics of September 1953, but conceded that minor refinements might still be needed. The contractor also asserted that its new configuration was "the best design supportable by the current stateof-the-art." However, delivery of the first test aircraft, already delayed by the program reorientation, would slip further if production was not authorized soon. Still in a quandary, the Air Force doubted that the new configuration would meet Convair's expectations, and refused to approve the model specifications. Even so, the Air Force in November asked ARDC to develop 2 important back-up systems, one for the Sperry bombing and navigation system, the other for the Emerson tail defense armament. That same month, after learning that Convair was about to reduce its labor force, the Air Force finally authorized limited fabrication of the new airframe.
After seeming to improve, the B/RB-58A's future once again appeared on the brink of disaster. A chief factor in the new crisis was SAC's dislike of the proposed aircraft. True to character, General LeMay had not changed his mind. At the urging of General LeMay, the Air Force in July 1934 instructed ARDC to initiate the research and development of an intercontinental bomber to succeed the B-52. This eventually promoted North American's ill-fated B-70, a bomber which had its origin in May 1933. Boeing was the recipient of the May 1933 study contract for a nuclear- or chemical-powered weapon system of intercontinental range. In 1933, the Air Force Council agreed that development of a nuclear-powered aircraft would not negate the requirement for a bomber using conventional fuel, and weapon systems 123 (nuclear-powered aircraft) and 1lOA (B-70) assumed their individual identities. Reminiscent of the B-38's case, North American in 1937 won the B-70 design competition over Boeing. In fact, based on the command's arguments of November 1952, a mid-1954 staff study, prepared by Maj. Gen. John P McConnell, SAC's Director of Plans, had excluded the B-58 from the 51-wing bomber force proposed for the period 1958-1965. At first unimpressed by the SAC omission, the Air Staff in late 1954 was having second thoughts. In early 1955, after General LeMay had directly confirmed to Gen. Nathan R Twining (Air Force Chief of Staff since 30 June 1953), that SAC wanted no B-58 aircraft for its operational inventory, the Air Force endorsed a thorough review of the program. A B-58 review board was appointed in February and chaired by Maj. Gen. Clarence S. Irvine, AMC Deputy for Production. The board faced the difficult task of recommending whether the B-58 program should be continued, modified, or canceled. General Boyd, one of the board's members, admitted that Convair's latest configuration might again not meet all requirements of the military characteristics, but still believed, that the B-58 should be built, even if the Air Force could not use it as originally intended. The B-58, the Wright Air Development Center Commander argued, represented major technical advances and, therefore, entailed technical uncertainties and the risk of high costs. These uncertainties would remain until "we have flown such an aircraft;" and "we must accept such a risk sooner or later."
The board studied anew other valued opinions that had been discussed in previous months. As already stated by Lt. Gen. Thomas S. Power, in charge of ARDC since April 1954, the B-58 was the first attempt to build a supersonic bomber (making in retrospect the production of supersonic fighters look relatively simple), and this task demanded extensive knowledge of aircraft materials and aerodynamic heating. The board's chairman agreed that from this standpoint the program was probably worth the money it had already consumed. Nevertheless, after an investment of 2 years and almost $200 million, no tangible achievements could be claimed. If the B-58 should now be canceled, the money would actually be lost, whereas another $300 million might suffice to build the 13 test-aircraft included in the reoriented program of April 1954. There were other pro-B-58 arguments. In his testimony before the review board, Convair's chief engineer maintained that, if allowed, the B-58 effort would produce the earliest and most inexpensive integrated weapon system, as well as a very outstanding bomber. At worst, he added, the B-58 would be superior to the existing B-47 medium bomber, a contention fully supported by General Power, who also noted that the aircraft might fulfill Tactical Air Command's requirements for a short-range attack bomber.
On 10 March 1955, the review board submitted its recommendations to the Air Force Council and to the Secretary of the Air Force. Aware that whatever suggestion was adopted could have far-reaching effects for years to come, the board took no chances. First, it emphatically recommended that the reoriented program be continued on a modified basis. Only 13 test vehicles would be ordered; they would be equipped from the start with J79 engines; and all back-up subsystems would be eliminated in order to reduce costs. The board observed that Convair could be asked to submit several new design proposals, one for a B-58 tactical bomber, one for special reconnaissance aircraft, and one for a long range B-58 interceptor. Finally, to complete developments vital to the design and operation of future strategic bomber weapon systems, the board did not exclude another possibility. Instead of limiting the program to 13 test-vehicles, it might be wise to buy also a number of B-58s for the operational inventory.
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