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The Convair F-106 Delta Dart served in the continental US, Alaska, and Iceland, as well as for brief periods in Germany and South Korea. In service, the official name ,"Delta Dart", was rarely used and was universally known as "The Six". Its first test flight was 26 December 1956. The Six was the primary all-weather interceptor aircraft of the US Air Force from the 1960s through the 1980s. Designed as the so-called "Ultimate Interceptor", it proved to be the last dedicated interceptor in US Air Force service to date.
The F-106 was the ultimate development of the USAF's interceptor program of the early 1950s.. The initial winner of this competition had been the F-102 Delta Dagger, but early versions of this aircraft had demonstrated extremely poor performance, limited to subsonic speeds and relatively low altitudes. During the testing program the F-102 underwent numerous changes to improve its performance. On 17 June 1956, the aircraft was officially re-designated as the F-106A.
The first prototype F-106, an aerodynamic test bed, flew on 26 December 1956 from Edwards Air Force Base, with the second, fitted with a fuller set of equipment, following 26 February 1957. Initial flight tests at the end of 1956 and beginning of 1957 were disappointing, with performance less than anticipated, while the engine and avionics proved unreliable. These problems, and the delays associated with them, nearly led to the abandoning of the program, but the Air Force decided to order 350 F-106s instead of the planned 1,000. After some minor redesign, the new aircraft, designated F-106A, were delivered to 15 fighter interceptor squadrons along with the F-106B two-seat combat-capable trainer variant, starting in October 1959.
On 15 December 1959, Major Joseph W. Rogers set a world speed record of 1,525.96 mph (2,455.79 km/h) in a Delta Dart at 40,500 ft (12,300 m). That year, Charles E. Myers flew the same model aircraft at 1,544 mph (2484 km/h). Nevertheless, Major Rogers received the award because cold war pressures dictated that a military pilot should be recognized.
Similar to the F-102, the F-106 was designed without a gun, or provision for carrying bombs, but it carried its missiles in an internal weapons bay for clean supersonic flight. It was armed with four Hughes AIM-4 Falcon air-to-air missiles, along with a single GAR-11/AIM-26A Falcon nuclear-tipped semi-active radar homing (SARH) missile (which detected reflected radar signals), or a 1.5 kiloton-warhead AIR-2 (MB-2) Genie air-to-air rocket intended to be fired into enemy bomber formations. Like its predecessor, the F-102 Delta Dagger, it could carry a drop tank under each wing. Later fighters such as the McDonnell Douglas F-4 Phantom II and McDonnell Douglas F-15 Eagle carried missiles recessed in the fuselage or externally, but stealth aircraft would re-adopt the idea of carrying missiles or bombs internally for reduced radar signature.
Although contemplated for use in the Vietnam War the F-106 never saw combat, nor was it exported to foreign users. Following the resolution of initial teething problems, in particular an ejection seat that killed the first 12 pilots to eject from the aircraft, its exceptional performance made it very popular with its pilots. After the cancellation of their own Avro Arrow, the Canadian government briefly considered purchasing the F-106C/D.
The F-106 was progressively updated in service, with improved avionics, a modified wing featuring a noticeable conical camber, an infrared search and track system, streamlined supersonic wing tanks which provided virtually no degradation to overall aircraft performance, better instrumentation, and features like an inflight refuelling receptacle and an arrestor hook for landing emergencies.
Air-to-air combat testing suggested "The Six" was a reasonable match for the McDonnell Douglas F-4 Phantom II in a dogfight, with superior high-altitude turn performance and overall maneuverability (aided by the aircraft's lower wing loading). However, the Phantom had better radar – operated by an additional crewman – and could carry a load of up to four radar-guided Sparrow and four infrared Sidewinder missiles, while the Falcon missiles proved a disappointment for dogfighting over Vietnam. The F-4 had a higher thrust/weight ratio, superior climb performance, and better high speed/low-altitude maneuverability, and could be used as a fighter-bomber. Air combat experience over Vietnam showed the need for increased pilot visibility and the utility of a built-in gun, which had been added to the "E" variant of USAF Phantoms.
The F-15A started replacing the F-106 in 1981, with "The Sixes" typically passed on to Air National Guard units. The F-106 remained in service in various USAF and ANG units until 1988.
Between 1 June 1983 and 1 August 1988 the Delta Darts were incrementally retired and sent to the Military Storage and Disposition Center in Arizona. When the need for a high performance Full Scaled Aerial Target Drone was required the USAF began withdrawing Delta Darts from storage. Starting in 1986, 194 of the surviving surplus aircraft were converted into target drones and these were designated QF-106As and used for target practice vehicles under the Pacer Six Program by the Aerial Targets Squadron. The last was destroyed in January 1998.
Six F-106s were retained by NASA for test purposes through 1998. An F-106B two-seat trainer was operated by NASA Langley Research Center between 1979 and 1991. This Delta Dart was used in research programs ranging from testing supersonic engines to improving maneuverability of fighters. Between 1980 and 1986 the aircraft was modified for the purpose of lightning strike research and became known as the Lightning Strike Plane and was struck 714 times without damage.