B-70 Valkyrie Construction
Naturally enough, the preliminary design proposals submitted in mid-1956 by Boeing and North American were quite different. Boeing utilized a conventional swept-wing configuration; North American, a canard-type, resembling a scaled-up Navaho missile. The North American SM-64A Navaho (System 104A) was a vertically launched, air-breathing, intercontinental surface-to-surface, delta-wing missile, with a length of 87 feet and a diameter of 0i feet. Production was canceled in July 1957 because of budgetary and technical problems. The Navaho development cost over $600 million, but the work expended on the canceled program was not a loss and benefited other projects significantly. Still, in order to attempt meeting the payload requirements and ranges stipulated in the spring of the year, the contractors had incorporated similar features in their respective designs. The aircraft envisioned by both would weigh some 750,000 pounds and require the use of cumbersome floating wing panels. These panels would carry fuel for the outgoing trip and be jettisoned when empty. Maximum speed might then exceed mach 2 by a significant margin.
The Boeing and North American preliminary designs had another common factor: both were unsatisfactory. The gross weights were excessive. The proposed fuel devices, whether fuel panels or straight floating wing tips, while promising to extend the aircraft's subsonic range, seemed impractical. To begin with, the enormous expendable panels (or non-folding floating wing tips) would create logistical problems and runway difficulties because of the total width of any airplane so equipped. In September, a disappointed Air Staff recommended that both contractors "return to the drawing board." And money being short, a more drastic decision followed that nearly spelled the program's cancellation. On 18 October, the Air Force discontinued the weapon system's Phase I development. Boeing and North American were allowed to resume their studies, but solely on a reduced research and development basis.
Concerned that the contractors might construe their contract's reorientation as resulting from lack of funds-an interpretation not far from the truth-and would merely mark time while refining their current designs, the Air Force promptly minimized the impact of its October decision. First, new work statements were issued, underscoring the necessity of achieving acceptable, but less exacting, performance characteristics. Then on 20 December, the Air Force sent identical letters to the presidents of Boeing and North American, asking that every possible means be explored to improve the aircraft's range "through complete redesign if necessary."
After the delay induced by the rejected proposals, events moved swiftly. By March 1957, it seemed almost certain that the new weapon system could be an all-supersonic cruise air vehicle as opposed to a "split-mission" (subsonic cruise-supersonic dash) aircraft. Theoretical research on the "supersonic wedge principle" conducted by the National Advisory Committee for Aerononautics in 1956, actually had much to do with the "graduation" to an all-supersonic flight pattern. In other words, aircraft designers had discovered that, if the entire design (especially engines, air induction system, and airframe) was geared for a single flight condition such as mach 3, the range of the supersonic system would compare favorably with that of a subsonic vehicle. Both contractors, independently, had also concluded that, as suggested by the Air Force, high-energy fuel would be needed and that its use should be extended to the engine afterburner.
In mid-1957, believing their re-oriented contractual commitments had been fulfilled, Boeing and North American asked for an early competitive selection of 1 contractor over the other. Dual contracting and dual funding made extra work and was costly. Moreover, the Air Research and Development Command was convinced that state-of-the-art advances had been fully exploited by both contractors. Further study of the project would mean more delay and be self-defeating. Hence, the tempo of activities quickened. On 30 August, the Air Force directed a 45-day competitive design period, ending with the onsite inspection of each contractor's facilities. On 18 September, the Air Force gave Boeing and North American the new system characteristics established for the competition. These characteristics called for a speed of mach 3 to mach 3.2, a target altitude of 70,000 to 75,000 feet, a range of 6,100 to 10,500 miles, and a gross weight between 475,000 and 490,000 pounds.
Meanwhile, a source selection evaluation group had been organized. It comprised 3 teams: representatives from the Air Research and Development Command, the Air Materiel Command, and, for the first time, a using command-the Strategic Air Command, in this case. The evaluation group, numbering about 60 members, reviewed the North American proposal during the last week of October; that of Boeing, during the first week of November. Due to the success of the 3-team evaluation group, the Air Force changed its source selection procedures, the using command becoming an integral part of the selecting process. The 3-team evaluations were presented to the Air Force Councilon 15 December. The North American proposal was found unaminously to be substantially superior to that of Boeing. The Air Force formally announced North American's selection on 23 December.
As winner of the 1957 competition, North American on 24 January 1958 signed contract AF33(600)-36599. Strictly speaking, this document again covered only the new weapon system's Phase I development. Just the same, availability of the first operational wing (30 planes and 15 test vehicles) was already planned for late 1965. In February 1958, believing that by late 1965 or thereabouts, when the RB-70 would become operational, other systems could better satisfy the reconnaissance requirements, the Air Force canceled the development of Weapon System 110L (part of WS 110A since 1956).
While the reconnaissance requirement was being deleted, an 18-month acceleration of the B-70 program was planned. This change, endorsed by the Air Research and Development Command and Air Materiel Command, scheduled the aircraft's first flight for December 1961 and formation of the first operational wing for August 1964. No performance decrease would result, and the increase in costs would not exceed $165 million. The Air Staff approved the accelerated plan in principle on 19 March 1958. In the same month, a revised general operational requirement was issued, updating such matters as the speed specification. In April, a preliminary operational concept was published.
In the fall of 1958, the Air Force's apparent optimism had a severe jolt. Gen. Thomas D. White, Air Force Chief of Staff since August 1957, announced that the B-70 program's planned acceleration was no longer viable because of funding limitations. A first flight, therefore, should not be expected before January 1962; an operational wing, in August 1965, at the earliest. This reversal damaged the program, particularly the weapon system's components. General White wanted more judicious use of currently available equipment and flight test inventory. He further wished to reduce the overall complexity of the bombing-navigation and missile guidance subsystems. Of greater import, and a harbinger that worse might yet come, General White also told his staff that the Eisenhower Administration believed that no large sums of money should be committed to the program before the B-70 prototype had proven itself. General White's words reflected the Administration's determination to hold military expenditures for radically new or unproven weapon systems to a minimum, while taking advantage of technological advances. Deployment of the free world's first long-range ballistic missiles, and accelerating the operational readiness of additional weapons systems of this type, which appeared more cost-effective and less speculative, fell under the purview of such a philosophy.
A development engineering inspection and mockup review were conducted at North American's Inglewood plant on 2 and 30 March 1959, respectively. The mockup review differed from the inspection in that it was styled to present the operational characteristics and suitability of the weapon system's configuration, rather than to introduce detailed system analysis and theory. On both occasions, the Air Force requested a great many changes, some of which were considered of primary importance. Nevertheless, almost 95 percent of the work generated by the requested alterations was accomplished before the end of the year.
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