F-102 "Delta Dagger"
Convair F-102, like the subsequent F-106, grew out of the company's experimental XF-92A the world's first delta wing airplane, originally known only as Model-7002, was successfully flown in September 1948. Like many other aerodynamic innovations, the delta wing had its inception in the wind tunnels of wartime Germany, although low aspect ratio wing forms were also studied by the US National Advisory Committee for Aeronautics. Dr. Alexander M. Lippisch (leader of the German program) helped develop the spectacular Me-163 rocket propelled interceptor for the Messerschmitt combine. Early design studies by NACA, captured reports of the Lippisch program, and later conferences with Lippisch himself convinced engineers of the Consolidated Vultee Aircraft Corporation (Convair) that the delta wing might be the answer to many of the problems of supersonic flight.
The Development Objective called for an advanced, specially designed interceptor (dubbed the "1954 Interceptor" for the year it was expected to become operational) that could surpass the estimated speed and altitude of Soviet intercontinental jet bombers. Recent intelligence warning and growth limits of the F-86, F-89, and F-94 interceptors spurred development of the Air Force ADO.
The ADO of January 1949 also departed radically from past procedures. The Air Force recognized that the increasing complexity of weapons no longer permitted the isolated and compartmented development of equipment and components which, when put together in a structural shell, formed an aircraft or missile. It concluded that the new interceptor should be developed in conformity with the Weapon System Concept. This concept (yet to be tried) integrated the design of the entire weapon system, making each component compatible with the others.
As one of the coordinated steps toward development of the new interceptor (Project MX-1554), the Air Force requested an airframe structurally capable of withstanding a speed of more than Mach 1, at an altitude of 50,000+ ft. The 1954 operational date was included in the bidding announcement. In October 1950, 3 months before the MX-1554 bidding ended, the Hughes Aircraft Company was awarded a contract for Project MX-1179, the Electronic Control System (ECS), "around" which the MX-1554 airframe would be built. Hughes had been working on new radars, fire-control systems (beginning with the E-1, developed for the gunfiring F-94A and F-86A aircraft) and related components since 1946. Production of the M-1179 ECS was programmed for 1953.
When the MX-1554 bidding closed in January 1951, six contractors had submitted nine proposals. Republic submitted three bids, North American two. Single proposals were made by Lockheed, Chance-Vought, Douglas and Convair. The Air Force on 2 July named three winners: Convair, Republic, and Lockheed, who were all to proceed with development through the mockup stage. At that time the firm providing the most promising design would be awarded a production contract. The MX-1554 three pronged development was short lived, however. The Air Force soon decided it was unwise to finance three concurrent Phase I development programs. It cancelled the Lockheed project in its entirety.
The LC awarded Convair authorized use of the Westinghouse J-40 power plant for the MX-1554, pending availability of the much more powerful Wright J-67. Performance requirements for the MX-1554/J-40 prototype were set at Mach 1.88 with a 56,500 ft altitude. The J-67 equipped MX-1554 combination, officially designated by the Air Force as the F-102 and also referred to as the 1954 or Ultimate Interceptor, would include the Hughes MX-1179 ECS and was expected to reach Mach 1.93 at 62,000 feet. Production, if approved, was programmed for 1953 or early 1954 at the latest. Although development of one of the Republic proposals (the Air Force designated XF-103) was still authorized, the LC of September 1951, in effect, declared Convair the undisputed winner of the design competition for the 1954 Interceptor.
The XF-103, one of the winning entries of the MX-1554 competition, was developed by the Republic Aviation Corporation from its AP-44A, a 1948 design for an all weather, high altitude defensive fighter. Like the AP-44A, the XF-103 (AP-57) presented numerous innovations, including all titanium construction, dual cycle propulsion, periscope for forward vision, and downward ejecting capsule for escape. The F-103 concept of a high altitude (80,Q00 feet) Mach 3 interceptor was also far ahead of the state of the art. After a full scale mockup inspection in March 1953, the Air Force decided to defer the XF-103 Phase II work and to extend for some 18 months the Republic Phase I development contract of September 1951. Republic finally received a contract for three experimental aircraft in June 1954 and the XF-103 (Weapon System 204A) Phase II program began 3 months later. In the following years, however, significant set backs slowed the development pace of the new XF-103. Low titanium priority, difficulties encountered in the titanium alloy fabrication process, difficulties in engine development, funding problems all had a hand in program slippage. After being reduced from three to one aircraft, the XF-103 program, still hampered by budgetary restrictions, was cancelled in September 1957--about 1 year before the aircraft's programmed first flight.
The Air Force decided to expedite the 1954 Interceptor program. The decision to accelerate Convair interceptor program halted further development of the Republic XF-91A, originally slated as an interim interceptor. Work stopped in October 1951, following the mockup inspection. The two experimental F-91s, already available, were modified to serve as high speed armament test vehicles by augmenting their jet engines with rocket motors.
The Air Force also confirmed that production of the new aircraft would follow the Cook Craigie Plan for early tooling, limited production at first, elimination of faults by test flights, and accelerated production thereafter. The Cook Craigie production plan was actually a mere concept, developed in the late forties by USAF Generals Laurence C. Craigie, DCS/Development, and Orval R. Cook, DCS/Materiel. This concept (closely related to the "fly before you buy" concept of the late sixties) could be expensive. The generals both thought "it was only applicable where you had a high degree of confidence that you were going to go into production."
To permit full scale testing prior to full scale production, initial production would use the existing Westinghouse J-40 engine (previously earmarked for the MX-1554 F-102 prototype). As also called for by the LC of September 1951, Convair would equip the MX-1554 F-102 with the more powerful J-67, as soon as feasible.
The November production go ahead, while reflecting the Air Force's urgent need of the 1954 Interceptor, did not ignore the fact that the J-67 engine and the MX-1179 ECS were yet to be produced. In December 1961, convinced that the J-67 would not be ready on schedule, the MX-1179 ECS might also be late, and the so called 1954 Interceptor would never meet its operational deadline, the Air Force changed plans. After surveying once again all existing fighter aircraft and future programmed designs that could be modified to an interceptor configuration, the Air Force gave Convair a new letter contract calling for the June 1953 production of an interim version of the MX-1564 interceptor. It decided to omit industrial competition, considering it time consuming as well as useless so soon after the MX-1554 competition. Moreover (and of primary concern to the Air Force) use of the Convair MX-1554 airframe for the interim interceptor would allow a thorough, rational, carefully phased development of both the interim and ultimate interceptors. One would lead into the other an arrangement very similar to that originally devised under the new weapon system concept and the Cook Craigie production plan.
The Air Force in December 1961 drew no specific operational requirements for the interim interceptor. The only stipulation (and the basis for the Air Force decision to buy the Convair aircraft) was that the interim interceptor be sufficiently advanced over North American's forth-coming F-86D to warrant its procurement. Similarly, the single guideline for selection of components specified that the engine, armament, and, if need be, the electronic control system (while being as technically progressive as possible) would be available to meet the production of the MX-1554 airframe. In any case, the Air Force in late 1951 did not contemplate any largescale production of the interim interceptor.
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