The Convair F-106 Delta Dart was the primary all-weather interceptor aircraft of the US Air Force from the 1960s through to the 1980s.
Designed as the so-called “Ultimate Interceptor”, F-106 Delta Dart proved to be the last dedicated interceptor in U.S. Air Force service to date. It was gradually retired during the 1980s, with the QF-106 drone conversions of the aircraft being used until 1998 under the Pacer Six Program.
The F-106 was developed from the F-102 Delta Dagger delta-wing fighter. The Convair F-102 Delta Dagger was an American interceptor aircraft that was built as part of the backbone of the US Air Force’s air defenses in the late 1950s. Entering service in 1956, its main purpose was to intercept invading Soviet strategic bomber fleets (primarily the Tupolev Tu-95) during the Cold War. 1,000 F-102s were built.
The 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.
A further improved version, the F-102B, was later renamed the F-106 Delta Dart. The new aircraft would be powered by a much more powerful afterburning turbojet engine. The first engine considered was a license-built version of the Bristol Olympus engine used in the Avro Vulcan to be built by Wright and designated J67 in US Air Force service. However, these engine problems were not resolved, and in early 1955 the Air Force approved the switch to the Pratt & Whitney J75.
The air force’s order plan is 1,000, but in fact this jet has only ordered 350 units, much less than originally planned. By the time the F-106A Delta Dart entered service during October of 1959, the jet was much closer to its designed capabilities than it had been during initial test. The single seat F-106A and the tandem twin seat F-106B combat-capable trainer became the country’s primary air defense weapons system and remained so for many years. With J-75 afterburning turbojet engine, the F-106 can reach a maximum speed of Mach 2.3.
Developed from F-102, it was no wonder that the F-106 had many similarities to its predecessor. Still the large-area, low-mounted delta-wing configuration including its triangular vertical tail fin atop the fuselage spine aft. The cockpit also retains the two-piece canopy with the position immediately behind the nose cone cluster containing 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. A standard 3-legged undercarriage with two main landing gear legs and a nose landing gear leg.
The production F-106 was fitted with the Hughes MA-1 integrated fire-control system, which when linked to the Semi-Automatic Ground Environment network for ground control interception missions, allowed the aircraft to be steered by ground-based controllers. The MA-1 proved extremely troublesome and was eventually upgraded more than 60 times in service.
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 AIM-26A Falcon nuclear-tipped semi-active radar homing missile, or a 1.5 kiloton-warhead AIR-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.
Ejection seats used in the F-106A evolved from the initial Weber catapult seat, which was inadequate for ejections above supersonic speeds or below 220 kilometres per hour at less than 610 metres. The second seat that replaced the Weber interim seat was the Convair Supersonic Rotational B-seat. Capable of use at supersonic speeds, the ejection sequence was complicated enough that pilots lost their lives using it. The final solution was another Weber seat which was adequate under zero-zero conditions. The end result was that the first twelve pilots to attempt ejection from the F-106A were killed in the attempt, but the final Weber ejection seat solution was adequate.
Convair built a total of 277 F-106As and 63 F-106Bs. The F-106A went into service in May of 1959. The F-106B entered service in July of 1960. In service, the F-106’s official name, “Delta Dart,” was rarely used, and the aircraft was universally known simply as “The Six.” Although contemplated for use in the Vietnam War the F-106 never saw combat, nor was it exported to foreign users.
Despite the level of sophistication found in the F-106 Delta Dart it was regarded by the Air Force as having the greatest mission-task loaded cockpit among all active US Air Force service aircraft flown in the 1970s. And despite being an excellent aircraft to fly, it required a competent and proficient pilot to wring every bit of its excellence out of it. It was also a very complex and sophisticated aircraft for its day, requiring a rather extensive and demanding ground service & maintenance schedule. Much of this was attributable to the intricacies of the complex Hughes MA-I Fire Control System that formed the heart and soul of the Six.
Given these requirements however, it was a reliable, dependable, and deadly accurate weapons platform with which to counter any conceivable threat of airspace penetration. Above all the Six was an absolute joy to fly – truly a pilot’s airplane – and was loved by all who worked in or around it. It was regarded with almost as much affection by those who maintained it, despite its time-intensive nature, as by those who actually flew it.Finally, the arrival of the McDonnell Douglas F-15A Eagle “air superiority” fighter brought an end to America’s last dedicated interceptor. Many of the remaining Delta Darts were expended as QF-106 targets during the 1990s.
