Staff Writer (Updated: 4/22/2016):
However, the F-102 was ever only truly an "interim" interceptor package for the envisioned engine and FCS development were delayed. As such, the series was fielded with the lower-performance Wright J57 turbojet engine and was only capable of Mach 1 speed flight. It was seen that the initial F-102A production model would serve to "bridge the gap" to the upcoming - and finalized F-102 form - this to become the "F-102B" production mark with its true engine and weapons package in place. The F-102B portion was evolved with the introduction of the Pratt & Whitney J-75-P-17 turbojet engine by way of larger air intakes and a variable geometry inlet duct (required of high-speed, high-altitude flight) within a lengthened fuselage assembly. The wings and vertical tailplane were revised to include additional surface area while improving stability. At the rear of the fuselage, an idle thrust reducer was added to the engine exhaust ring. Such were the myriad of major changes that the aircraft was ordered as a pair of "YF-106A" prototype models by the USAF. First flight was on December 26th, 1956 with the USAF envisioning a fleet of 1,000 such aircraft in its inventory.
As with the trial F-102 aircraft before it, the YF-106 proved limited in its initial performance gains despite the additions and changes to her design. Complications soon arose with the highly-advanced fire control system and temperamental engine that the project teetered on oblivion due to rising costs and delays. This led the USAF to cut back on the total procurement contract of 1,000 aircraft to just 350 examples. Engineers continued their work on the YF-106 until it satisfied USAF requirements - including the Mach 2 speed potential. The aircraft was finalized and formally accepted into service as the "F-106A" single-seat production mark to which 277 examples were ultimately produced. Introduction of the series was announced in June 1959 with deliveries to the 539th Fighter Interceptor Squadron.
Externally, the F-106 shared much of the sharp lines and contours of the F-102 before it. It retained the large-area, low-mounted delta-wing configuration including its triangular vertical tail fin atop the fuselage spine aft. The cockpit also retained the two-piece framed canopy with the emplacement sitting directly behind the nose cone assembly housing the radar. The engine was buried within the tubular fuselage which was gradually "pinched" at amidships. The engine was aspirated by a pair of rounded, trapezoidal-shaped air intakes aft of the cockpit (the F-102 sported its intakes directly against the cockpit sides). As in the F-102, the F-106 utilized a standardized three-legged undercarriage made up of two main landing gear legs and a nose landing gear leg. The production F-106 was fitted with the Hughes MA-1 fire control system which could automatically guide the aircraft to the target in question, select the appropriate missile armament and fire without input from the pilot - the pilot more or less supervising the process for quality control.