The Convair F-106A Delta Dart is regarded by many as being the finest all-weather interceptor ever built. It served on active duty with the US Air Force for almost 28 years, much longer than most of its contemporaries.
The F-106 had its origin in an early-1949 request by the USAF for an advanced interceptor capable of supersonic performance that would surpass the speed and altitude performance of new Soviet intercontinental bombers which intelligence services warned would soon be available. The North American F-86D Sabre, the Northrop F-89 Scorpion, and the Lockheed F-94 Starfire were all subsonic aircraft, and were deemed to have insufficient growth potential to be able to meet this new threat. This project came to be known as the "1954 Interceptor", after the year that new interceptor would supposedly be entering service.
At that time, the Air Force recognized that the increasing complexity of modern weapons made it no longer practical to attempt to develop equipment, airframes, electronics, engines, and other components in isolation and to expect them to work properly when they were put together in the final product. To address this problem, the Air Force introduced the "weapons system" concept, in which components of the the new interceptor would be integrated with each other from the very beginning, making sure that the various systems would be compatible with each other when they were incorporated into the final aircraft. The project was given the designation WS-201A, where WS stood for "Weapons System". As originally conceived, WS-201A was a weapons system consisting of air-to-air guided missiles, all-weather search and fire control radar, all housed in an airframe capable of supersonic flight.
The electronics package for the new WS-201A system came first. Project MX-1179 was the designation given to that portion of the project dedicated to the armament and electronic fire-control system of the 1954 Interceptor. In October of 1950, the Hughes Aircraft Company was named the winner of the MX-1179 contract. The Hughes proposal consisted of a MA-1 fire control system acting in conjunction with GAR-1 Falcon air-to-air guided missiles. For a brief time, the Falcon missile was known as the F-98, a fighter designation.
The airframe part of the project was designated MX-1554. Proposals for the airframe portion were requested by the Air Force on June 18, 1950. When the bidding closed in January of 1951, nine proposals had been submitted by six different manufacturers. Republic submitted three separate proposals, North American submitted two, and single proposals were made by Chance-Vought, Douglas, Lockheed, and Convair.
On July 2, 1951, the Air Force announced that designs by Convair, Lockheed, and Republic had been selected to proceed with preliminary development. All three companies were to proceed with their designs all the way to the mockup stage, with the design deemed most promising at that time being awarded a production contract. Later, the USAF deemed it too costly to carry through with three concurrent development programs, and it cancelled the Lockheed project in its entirety. The Convair and Republic entries were given the go-ahead to proceed.
The Republic entry bore the company designation of AP-57, where the AP stood for "Advanced Project". It called for an extremely advanced aircraft capable of achieving a Mach 4 performance at altitudes of up to 80,000 feet. This was clearly a quantum leap in the state of the art for the early 1950s.
The Convair entry in the MX-1554 project was closely related to the experimental XF-92A which Convair had built in 1948 as a test bed to provide data for the proposed F-92 Mach 1.5 fighter. This work had been performed in consulation with Dr. Alexander Lippisch, who had done pioneering work in Germany on delta-winged aircraft during the war, and Convair had become convinced that the delta configuration provided a viable solution to the problems of supersonic flight. The XF-92A had been the first powered delta-wined aircraft to fly, but the F-92 project had itself been cancelled before any prototype could be built.
On September 11, 1951, Convair received a contract for its delta winged design which was assigned the designation F-102. Work on the competing Republic design was also authorized, and that aircraft was assigned the designation XF-103. However, the XF-103 was so far ahead of the state of the art that it was deemed too risky to be a serious contender for the 1954 Interceptor project, which made the F-102 for all practical purposes the winner of the contest.
The Air Force authorized the fitting of a Westinghouse J40 turbojet in the first few examples of the F-102, but later production aircraft were to be powered by the appreciably more-powerful Wright J67 turbojet, which was a license-built version of the Bristol Olympus. The J40-powered F-102 was to be capable of a speed of Mach 1.88 at 56,500 feet, with the J67 production version capable of Mach 1.93 at 62,000 feet.
In order to expedite the development of its 1954 Interceptor program, the Air Force adopted the so-called "Cook-Craigie" program, named for its originators, Generals Laurence C. Craigie and Orval R. Cook. During the late 1940s, these two officers had developed a concept of an aircraft development program in which the usual prototype stage would be skipped. Instead of waiting to start full-scale production until the prototypes had passed flight testing and the bugs had been ironed out, the Cook-Craigie plan called for the delivery of a small number of production aircraft during the flight testing phase so that any major changes could be incorporated into permanent factory tooling in order for combat-ready aircraft to be delivered when mass production started. This program is inherently risky--it can produce a new combat aircraft in a hurry if everything goes according to plan during flight testing, but can result in a lot of costly and time-consuming fixes in the field if unexpected problems turn up. The Cook-Cragie plan is really viable only if there is a high degree of confidence that the aircraft is really going to go into production. Since the F-102 was basically a scaled-up XF-92A, the risk was deemed work taking.
By December of 1951, it was apparent that the Wright J67 engine and the MA-1 fire-control system would not be ready in time. This forced the USAF to change its plans. At that time, the Air Force decided to proceed with an interim version of its 1954 Interceptor, one which could be introduced into service at an early date, pending the availability of the fully-developed version at a later time. The interim version was to be designated F-102A, with the fully-developed advanced version being designated F-102B. The F-102A was to be powered by the less-powerful Pratt & Whitney J57 turbojet, but the F-102B was to retain the high-thrust J67. The F-102A would be equipped with an interim fire-control system, but the F-102B would be equipped from the outset with the highly-sophisticated fire control system being developed by Hughes under project MX-1179.
Although the F-102A was considered only as an interim version pending the availability of the F-102B, the F-102A ran into some unexpected developmental difficulties and fell behind schedule. A lot of money that had originally been planned for the F-102B now had to be diverted into fixing the F-102A's problems. Consequently, the F-102B fell even further behind schedule and began to lose some of its original high priority.
By mid-1953, the MX-1179 fire control system (later to be known as the MA-1) was slipping badly, and it took another year before an experimental installation could be installed aboard a T-29B for testing. At the same time, the Wright J67 engine was experiencing difficulties of its own. The Air Force had to consider alternative powerplants, and finally settled on the Pratt & Whitney J75, which was an advanced version of the J57 which was used in the F-102A. The substitution of the J75 engine for the J67 was approved in early 1955.
In the early 1950s, the Canadian government considered getting involved in the F-102B program. However, they opted instead to pursue a separate interceptor project, known as the Avro CF-105 Arrow.
Seventeen F-102Bs were ordered in November of 1955. Their serials were 56-451/467. The F-102B mockup was ready for inspection in December of 1955. On April 18, 1956, the Air Force finalized the F-102B production contract of the previous November, earmarking all of the 17 aircraft ordered exclusively for testing. One prototype was to be delivered in December of 1956, with the others to follow in January of 1957.
On June 17, 1956, the designation of the F-102B was changed to F-106A. This redesignation was a recognition of the past technical differences that had distorted the original F-102 program and also a recognition that the F-102B was by now a completely different aircraft from the F-102A and was far more advanced.
In September of 1956, the Air Force specified that the F-106A would be available by August of 1958 (some four years later than initially planned) and that it had to compatible with the Semi-Automatic Ground Environment (SAGE) up to a radius of 430 miles and an altitude as high as 70,000 feet. Interceptions would be accomplished at speeds of up to Mach 2 at 35,000 feet. It was to be capable of launching air-to-air guided missiles and rockets under the control of the Hughes MA-1 fire control system.
The wing of the F-106A was virtually identical to that of the F-102A. The aircraft with FY 1956 serial numbers had outer-wing boundary layer fences as on the F-102A, but these were replaced on FY 1957 and later aircraft by leading edge slots. The wing was "wet" with no fuel bladders. Fuel transfer was accomplished by low air pressure bleeding off low-psi air pressure from engine into tanks. It was thought, however, that combat damage (even perhaps a single bullet hole in the wing) could incapacitate the entire system.
The major external difference was in the fuselage, which had a much more streamlined shape. The variable-ramp air intakes were moved well aft of the nose and mounted closer to the engine. The shape of the fin and rudder were changed and a clamshell-type airbrake was fitted at the base of the vertical fin.
A new undercarriage was fitted with steerable twin-nosewheels.
On the first F-106s, the upper and lower rotating navigation beacon lights (located immediately aft of the canopy in the dorsal position and immediately behind the nosewheel on the belly of the aircraft) retracted when the aircraft went supersonic. In later years, this feature was disabled.
The Pratt & Whitney J75 twin-spool, axial-flow afterburning turbojet was the same engine which powered the Republic F-105 Thunderchief. It was rated at 15,000 lb.st dry and 23,500 lb.s.t with afterburner.
The pilot sat well ahead of the engine air intakes. As with the F-102, the F-106 featured optically-flat windscreens which met at their forward edges. The metal strip that was located where the windscreens met was directly in front of the pilot's face and severely restricted his forward vision.
As on the F-102A, the all-missile armament was housed internally in a spacious ventral weapons bay that was closed by pneumatically-operated double-folding doors. The all-missile armament consisted of a single Douglas MB-1 (AIR-2A or 2B) Genie unguided missile equipped with a 1.5 kT nuclear warhead plus four Hughes GAR-3 Falcon radar- homing or GAR-4 infrared-homing (later redesignated AIM-4E and AIM-4G respectively) air-to-air missiles. The unguided 2.75-inch missile armament of the F-102A was omitted.
The Genie missile was carried in the rear half of the missile bay. It was powered by a 36,600 lb.st. Thiokol TU-389 rocket motor and was unguided, relying on its 1.5 kT nuclear warhead to ensure a kill. Launch weight was 822 pounds and maximum velocity was Mach 3.3. Snap-out fins gave the missile stability during flight. Range was about 8 miles, and flight time to target was about 12 seconds and a blast radius of about 1000 feet.
The Falcons were conventional warhead adaptations of the nuclear-tipped AIM-26A Falcon. The two semi-active radar homing AIM-4E Falcons were carried in the forward half of the weapons bay, whereas the AIM-4G infrared-homing missiles were carried in the rear half of the weapons bay flanking the Genie missile. All Falcon missiles were contact fused, with the fuses located on the leading edges of all four fins, so that a direct hit on the target was needed to score a kill.
The Falcon missiles could be launched in salvo or in pairs. Because the aerodynamic range of the AIM-4F was greater than the range of its seeker and tracker radar sensor, the IR-guided AIM-4G was the preferred means of attacking a fast-moving target. At high closure speeds, the MA-1 fire control system would present two separate firing solutions, one for the AIM-4G and the other for the AIM-4F. If all four missiles were to be fired, the 4Gs were fired first so that they would not inadvertently lock onto the radar guided missiles rather than the target. As a further precaution, the 4F pair was carried in the rear bay. The 4F and 4G missiles were fired in like pairs and ripple-fired so that one would always be ahead of the other. The missiles were fired in pairs because the pneumatic system had only enough high pressure stored for three cycles of the armament system. There were essentially three shots available-one Genie, one pair of AIM-4Fs and one pair of AIM-4Gs.
The Hughes MA-1 fire control system incorporated the first digital computer to be built into a fire control system. A datalink with NORAD's SAGE system meant that radio silence could be maintained throughout the intercept, while an autopilot allowed the ground controllers to "fly" the aircraft during the final approach to the target. A Tactical Situation Display (TSD) between the pilot's feet showed a moving map of the route across the ground during the intercept.
The first F-106A (56-0451) was finally available by the end of 1956. The first flight was made by Convair test pilot Richard L. Johnson at Edwards AFB on December 26, 1956. He was the same pilot who had made the maiden flight of the F-102. The flight was not entirely glitch-free--it had to be aborted early due to air turbine motor frequency fluctuations, and the speed brakes opened but would not close. Consequently, the aircraft did not go supersonic on its first flight. The second aircraft (56-0452) followed on February 26, 1957. They were both powered by the YJ75-P-1 engine. The first two aircraft were not equipped with the MA-1 system, carrying nose ballast to compensate for the missing weight.
The test and development work on the F-16 was divided into six phases. Phase I was conducted by the contractor, and Phase II was conducted by the Air Force. Phase II tests wee carried out between May and June of 1957. The first 12 aircraft off the production line were devoted to tests at Edwards AFB in California. They differed from the prototypes in having J75-P-9 engines. Early testing reached a speed of Mach 1.9 and an altitude of 57,000 feet, but this was still well below expectations. In addition, the F-106A's acceleration was significantly below Convair's estimates, and it took almost 4 1/2 minutes to accelerate from Mach 1 to Mach 1.7 and another 2 1/2 minutes to accelerate to Mach 1.8. With such poor acceleration, it was felt that Mach numbers above 1.7 would not be tactically usable.
The poor speed and acceleration was cured by altering the aircraft's air intake cowling and charging ejectors. The capture area of the intake ducts was enlarged and the duct lips were thinned down. There were also problems with the reliability of the J75-P-9 engine. Eventually, the more powerful J75-P-17 engine was substituted, which was rated at 17,200 lb.s.t. dry and 24,500 lb.s.t. with afterburner. There were further problems with the MA-1 fire control system and with the cockpit layout. Originally, the control column had occupied the traditional center location, but was later moved to the side at USAF insistence in order to ensure an unrestricted view of the Horizontal Situation Indicator. This arrangement turned out not to be viable, and the control column was later moved back to the center and provided with a two-handed grip for both radar and aircraft control. The right-hand grip was used for control of the aircraft and the left-hand grip was used for operation of the radar. A button in the middle of the yoke gave the pilot control of the radar antenna, and another button on the left grip enabled the pilot to put the pipper on the target by following directions on the radar scope. The pilot selected the missiles to be fired by using a switch on the left console, with the trigger that was used to launch the missiles being on the right hand grip.
Early test aircraft had explored both conventional round-faced instrument panels and panels with vertical-tape instruments. However, the first three squadrons of F-106As were sent to the field with analog or round instrument dials. Eventually, the vertical-tape instrument set (know as Integrated Instrument Display, or IID) was made standard with aircraft 58-0759. Some of the early aircraft were subsequently upgraded with IID, but many never got the vertical tapes.
Initial aircraft had boundary layer fences as on the F-102, but production aircraft had wing leading-edge slots instead. The first twelve aircraft were temporarily designated JF-106A for flight tests, but a total of thirty-seven (including the first two aircraft) were used for flight test development.
In mid-1957, the F-106A was given the popular name Delta Dart.
Originally, the Air Force had planned to acquire 1000 Delta Darts, enough to equip some forty Air Defense Command (ADC) squadrons. However, by 1957 the delays in the F-106 program and the problems with the engine and the fire control system had resulted in the necessity of other interceptors such as the McDonnell F-101B Voodoo having been ordered as a stop-gap measure, and the F-106 had lost some of its urgent priority. For a while, serious consideration was given to cancelling the entire F-106 program, or else to redesigning the aircraft as a long-range interceptor. Although the F-106 survived intact, shortages of funds caused a drastic cutback in the number of F-106As on order. By September 1958 the total order of F-106 interceptors had been cut by a factor of three, enabling only fourteen squadrons and a training unit to be equipped. As a result, only a further 260 F-106As were ordered. Since the cutback was so drastic, a decision was made in August of 1959 to convert all of the existing 35 F-106A test aircraft to operational status (Model 8-24 standards) and turn them over to the interceptor squadrons.
In September of 1958, an early F-106A (serial number 57-0235) was allocated to Ames Research Center at Moffett Field in California for tests of the MA-1 fire control system.
On May 30, 1959, the first F-106As were delivered to the Air Defense Command's 539th FIS at McGuire AFB in New Jersey, replacing the F-86L. However, the first operational unit was the 498th Fighter Interceptor Squadron based at Geiger AFB in Washington. This was no less than five years later than originally planned. Even then, numerous problems kept the Delta Dart from being declared fully operational until October 31, 1959. The remaining 13 squadrons were re-equipped with the F-106A by the end of 1960.
On December 15, 1959, a Delta Dart (56-467) flown by Major Joseph W. Rogers set a world's absolute speed record of 1525.96 mph at 40,500 feet. This beat the previous record of 1483.83 mph, set by Georgiy Mossolov in the Soviet Ye-6/3 on October 31 of that year.
Initial operational deployment turned up all sorts of problems--generator defects, fuel-flow deficiencies (particularly acute in cold weather), and fuel-combustion-starter malfunctions. In December of 1959, after a canopy had been accidentally jettisoned in flight, all F-106s were temporarily grounded until the problem could be fixed.
The MA-1 fire control system carried by the F-106A was initially quite unreliable and was subjected to lots of in-service modifications in an attempt to fix its chronic problems. The MA-1 system was upgraded no less than 60 times during the Delta Dart's long service life. In 1960, devices for long-range detection and electronic counter-countermeasures equipment were added, along with the capability for using angle chaff, silent lobing, and pulse-to-pulse frequency techniques. Anti-chaff devices were added in an effort to defeat enemy attempts to confuse the fire control system by dropping bits of radar-reflective strips. The modification programs involved 314 F-106As and were completed by the end of 1963.
The F-106A operated in conjunction with the SAGE (Semi-Automatic Ground Environment) network which was linked via the Hughes MA-1 fire-control system to the F-106. It operated by plotting the course needed to intercept an enemy aircraft, automatically sighted the target, fired the air-to-air missiles, and then automatically placed the F-106 on the correct course to disengage. The F-106 could actually be fully computer-flown during most of its mission, the pilot actually being needed only for takeoff, landing, or in case something went wrong with the automation.
Flight testing continued until early 1961, with each phase of the test program turning up a whole host of problems which required important engineering changes. Each change had to be defined, engineered, reviewed, and approved for production before modification of aircraft off the assembly line could begin. The Cook-Cragie production policy only made problems worse, and by 1960, the Air Defense Command had so many different F-106 configurations out in the field that maintenance support was a nightmare.
Because of the numerous modifications to the MA-1 fire control system made during production, a major modification project named *Wild Goose* was initiated in September of 1960 to bring the earlier F-106s up to the latest production standard. Early in 1960, ADC could list 63 changes in the F-106A's fire control system and 67 changes in the airframe that would be required to make early F-106s equivalent to the machines currently coming off the production line. Lasting a full year, the program involved roving AMC field assistance teams supported by ADC maintenance teams working at ADC bases.
The 277th and last F-106A was delivered on July 20, 1961. The production run also included 63 F-106B two-seaters, for a total of 340 aircraft.
In late 1961, Secretary of Defense Robert S. McNamara spoke of reopening the F-106 production line to build another 36 aircraft (rather than the 80 originally budgeted for in FY 1961). However, the ADC had heard so much about the capabilities of the Navy's F4H-1 Phantom two-seat interceptor that it thought that it might be a better idea to purchase some F4H-1s rather than buy additional F-106s. The USAF called for a competition-named Project High Speed-between the F-106 and the Navy's F4H-1 Phantom. It was designed to evaluate the capabilities of these two aircraft to perform similar missions. During the competition, the Phantom's APQ-72 radar was more reliable and had longer detection and lock-on ranges than the MA-1 system of the F-106. However, in many sorties F-106 pilots "shot down" their F4H adversaries in visual range combat situations. In the event, neither aircraft got the nod for additional ADC interceptor orders, and in December of 1961, the USAF announced that the F4H/F-110 would be acquired for the Tactical Air Command and that ADC would get no new interceptors.
Even after all aircraft had been delivered, reliability problems continued to plague the MA-1 and ASQ-25 systems. Throughout its long service life, the F-106A was continually upgraded and improved to correct these problems. The *Broad Jump* modification program started in late 1960 was a long-term program for general improvements in the F-106A. This program was carried out by people at the Sacramento Air Material Area, and it extended through early 1963. Among the changes introduced by this program was the fitting of an infrared search-and-track sight that could operate at low altitudes and against varied backgrounds. The unit retracted into a fairing in front of the cockpit.
In 1962, F-106As were fitted with a Sheaffer Spring Hook arrester system designed to engage wires at the end of the runway in the event of an landing overshoot, becoming the first USAF combat aircraft to be so equipped. The F-106A was definitely NEVER intended for carrier-based operations! :-)
The F-106 had to be grounded again on September 26, 1961 to make repairs to the fuel system which had caused two crashes. This order did not affect the F-106s that were on alert with ADC, but it did affect those used for training and transition flying. In response to this grounding, the *Dart Board* retrofit and modification program took place in 1961-62. This program finally fixed the problem with flame-outs from fuel starvation which had affected earlier Delta Darts. A thermal flash blindness protection hood was also fitted. Perhaps the most significant of these changes was, however, the revision of the ejection system for the F-106.
The ejection seat fitted to early F-106s was a Weber-built variation of the seat used by the F-102. It was an open, catapult-only seat which used an explosive charge to throw it out of the aircraft. It was thought that this seat would be inadequate for ejections at supersonic speeds, and it was replaced by a Convair-designed "B"-seat. It is not sure what the letter B stood for, but pilots believed that it was so named because it resembled a bobsled. It was designed with supersonic ejection specifically in mind. It was demonstrated in 15 sled tests and 11 flight tests. The first live test ejection with the Convair-designed seat took place when Technical Sergeant Games Howell ejected safely from an F-106B piloted by Major James Hendrix on June 6, 1961.
The ejection sequence with the Convar B-type seat was quite complicated. The pilot initiated the sequence by pulling a D-ring, which jettisoned the canopy, retracted and locked the shoulder harness, retracted the occupant's feet, and raised the foot pans, seat pan and leg guards. While all this was happening, the pilot had to pull the D-ring a second time to disconnect the seat actuator and fire the vertical thruster which propelled the seat up on its rail. The rotational thrusters then fired, causing the seat to rotate into a horizontal position on top of the aircraft. Once there, gas-operated stabilization booms extended, attachment bolts fired, and the rocket motor ignited to propel the seat away from the aircraft.
The new Convair-designed ejector seat was not very popular with F-106 pilots, and there were some unsuccessful ejections that resulted in pilot fatalities. Frustrated with the complexity and unreliability of the Convair B-seat, the USAF contracted in 1965 with the Weber Aircraft Corporation for the design of a "zero-zero" seat for the F-106. It was recognized that high-altitude supersonic ejections were actually quite rare, and that the high-runner cases were more likely to be ejections at relatively low altitudes and low speeds. Weber delivered the first seat in only 45 days. The new Weber seat was quite effective, and was quickly retrofitted through the entire F-106 fleet.
In 1965, an new TACAN system was installed which used microelectronic circuits and was one-third the size and weight of the existing system.
The F-106A surprised everyone by having a good maneuverability and showing potential as being an excellent dogfighter. There was some thought to using the F-106 for top cover in Vietnam. Among the suggestions was to apply tactical camouflage, to fit a clear-view canopy, and to add an internal cannon armament. Although the F-106 never actually did serve in Vietnam, the suggestion of the addition of a gun was taken seriously. The gun was not intended for air-to-air combat against enemy fighters, but was primarily intended to provide extra firepower for a better close-in kill potential against enemy bombers, but it was thought that it might also be useful in attacking bombers flying at low altitude.
In support of this program, Convair issued a proposal to re-equip the F-106 with an internal cannon, an optical gunsight, and a clear-view cockpit canopy in a program known as Project Sharp Shooter. An internal 20-mm M61A1 rotary cannon with 650 rounds was fitted inside the rear half of the weapons bay, replacing the Genie nuclear-tipped rocket. However, the four AIM-4F/G Super Falcon missiles could still be carried. The gun system was installed as a package inside an enclosure which was mounted inside the missile bay and which provided an aerodynamic shield for the portion of the gun protruding below the missile bay. Gun-equipped F-106As could be distinguished by a bulged fairing underneath the fuselage which provided clearance for the rotating barrels of the cannon. As part of the program, a new "clear-topped" canopy was tested, which eliminated the metal strip above the pilot's head, markedly improving the cockpit visibility, at least immediately above.
The gun installation was first tried on F-106A 58-795 and subsequently on 59-092. A prototype gunsight was developed at Tyndall AFB. The gun was installed only on those F-106s that had vertical tape instruments. When firing, the Vulcan was limited to only 4500 rounds per minute (rather than the 6000 rpm available when installed on the F-4E) due to limitations in the hydraulic pump which rotated the weapon. However, this innovation was not provided for the F-106B two-seater. The first test of the gun installation took place on February 10, 1969 on 58-795.
The idea of painting the F-106 in camouflage scheme was abandoned, when it was found that there was no significant advantage in doing so. In the event, the F-106 never went to Vietnam.
In the late 1960s, the F-106 was provided with newly-designed larger-capacity underwing tanks. These new tanks were often called "supersonic tanks", since they could be carried underneath the wings at any speed. They had a 360 US-gallon capacity, 50 percent larger than the 227-gallon tanks that were previously carried. The tanks were jettisonable, but this capability was rarely used in practice. The tanks were routinely carried on all but the shortest-range intercepts.
In conjunction with the new underwing tanks, an inflight refuelling capability was retrofitted to all surviving F-106s. This was done by retrofitting a slipway receptacle in a dorsal position behind the pilot. The first refuelling installations were installed in 1967.
The F-106 served mainly in the continental United States, in Alaska, Iceland, and in Canada, but it did serve for short spells in Germany and South Korea. Although the F-106 was briefly deployed to Osan AFB in Korea in February of 1968 to provide air defense during the *Pueblo* incident, the Delta Dart never saw any combat.
From 1972 onwards, the McDonnell Douglas F-15 Eagle gradually began to replace the Delta Dart in ADC squadrons. As they were removed from Air Force service, they were passed along to the Air National Guard. First ANG unit to receive the F-106 was the 186th FIS of the Montana ANG, based at Great Falls, which took delivery of its first planes on April 3, 1972. Six ANG units flew the F-106 on Air Defense Command mission. The last Delta Dart-equipped Air Force squadron, the 119th FIS based at Atlantic City, New Jersey flew its final alert duty on July 7, 1988. The ANG units continued to fly the last few Delta Darts for only a few months longer after the USAF had relinquished the type. The last ANG to relinquish its F-106s was the 119th FIS of the New Jersey ANG, which sent its last plane to AMARC in August of 1988.
During its long service life, the F-106A had the distinction of recording the lowest single-engined aircraft accident record in USAF history. Despite this, out of a total production of 340 aircraft, 112 (including 17 two-seat F-106Bs) were lost in crashes or in ground fires during the 29 year career of the Delta Dart.
As F-106As were withdrawn from active duty, they were ferried out to Davis-Monthan AFB in Arizona where they were placed in storage. The first F-106 went to storage in January of 1982. The last three F-106s (from the Atlantic City-based 119th FIS of the New Jersey ANG) departed for Davis Monthan AFB in August of 1988.
In 1986, a contract was awarded to Flight Systems Inc. (later Honeywell) to modify 194 surplus Delta Darts stored at Davis-Monthan AFB in Arizona to QF-106A target drone configuration. This program came to be known as Pacer Six, and the first flight of a converted drone took place in July of 1987. Following the completion of an initial batch of ten QF-106s in 1990, most of the work was transferred to the USAF itself. Much of the conversion work was done before the aircraft were removed from storage at AMARC, with further work being carried out at East St Louis, Illinois. The QF-106s began operating as a Full-Scale Aerial Target (FSAT) in late 1991 at White Sands Missile Range in New Mexico, and later at the Eglin Gulf Test Range in Florida (based at Holloman and Tyndall). A typical mission would employ the QF-106 as a target for an infrared homing missile. The aircraft had burners placed on pylons underneath the wings to act as IR sources for heat-seeking missiles, but it must be admitted that no real enemy would be so accommodating as to add these burners to make their planes better targets. However, the intention of the program was for the QF-106 to survive repeated engagements with air-to-air missiles, to make it possible for each QF-106 to last as long as possible before it was destroyed. The last shootdown of a QF-106 (57-2524) took place at Holloman AFB on February 20, 1997. Today, the QF-106 has been replaced by QF-4 Phantom drones.
The last mission flown by an F-106 was as a participant in Project Eclipse, a joint USAF/NASA project to demonstrate the validity of a concept for a reusable launch vehicle that would carry payloads into orbit. QF-106 59-130 was towed into the air by an NC-141A Starlifter (61-2775) by using a synthetic rope. The first flight was made on December 20, 1997 and the last test took place on February 6, 1998. The tests were made to explore the feasiblity of having a Boeing 747 to tow a RLV known as the Astroliner to 45,000 feet, where the Astroliner would fire its rocket engines and fly into orbit. On May 1, 1998, this last flyable F-106 flew from Edwards to AMARC. I do not believe that this concept was explored any further.
Today, there are 10 F-106s in museums, and at least 21 are still in storage at Davis Monthan AFB. Some of these may end up in museums as well.
56-451/467 Convair F-106A Delta Dart 57-229/246 Convair F-106A-CO Delta Dart 57-2453/2455 Convair F-106A-64-CO Delta Dart 57-2456/2460 Convair F-106A-70-CO Delta Dart 57-2461/2465 Convair F-106A-75-CO Delta Dart 57-2466/2477 Convair F-106A-80-CO Delta Dart 57-2478/2485 Convair F-106A-85-CO Delta Dart 57-2486/2506 Convair F-106A-90-CO Delta Dart 58-759/771 Convair F-106A-95-CO Delta Dart 58-772/798 Convair F-106A-100-CO Delta Dart 58-799/899 Cancelled contract for Convair F-106A Delta Dart 59-001/030 Convair F-106A-105-CO Delta Dart 59-031/059 Convair F-106A-110-CO Delta Dart 59-060/086 Convair F-106A-120-CO Delta Dart 59-087/111 Convair F-106A-125-CO Delta Dart 59-112/135 Convair F-106A-130-CO Delta Dart 59-136/148 Convair F-106A-135-CO Delta Dart 59-166/204 Cancelled contract for F-106A
Engine: One Pratt & Whitney J75-P-17 turbojet, 17,200 lb.s.t. dry and 24,500 lb.s.t with afterburning. Performance: Maximum speed: 1525 mph at 40,000 feet (Mach 2.31), 1327 mph at 35,000 feet. Landing speed was 173 mph Initial climb rate was 42,800 feet per minute. Service ceiling was 57,000 feet. Combat radius was 575 miles. Maximum range with maximum external fuel was 1809 miles. Maximum ferry range was 2700 miles at 610 mph at 41,000 feet Weights were 23,646 pounds empty, 38,700 pounds combat weight, 35,500 pounds gross, and 41,831 pounds maximum takeoff. Dimensions: wingspan 38 feet 3 1/2 inches, length 70 feet 8 3/4 inches, height 20 feet 3 1/4 inches, wing area 697.8 square feet. Maximum fuel load was 1440 US gallons. Armament consisted of one Douglas MB-1 (AIR-2A or 2B) Genie unguided missile with a nuclear warhead of 1.5 kT yield and four Hughes GAR-3 or GAR-4 (later redesignated AIM-4E and AIM-4G respectively) radar or infrared-homing missiles. All these missiles were housed within the internal weapons bay. In later installations, a single 20-mm M61A1 rotary cannon replaced the Genie nuclear-tipped missile in the internal weapons bay.