History of the Convair F-106 Delta Dart

Manufacture Model 8-24   /   Weapon System 201B

Convair Aircraft Plant, San Diego, CA


The Convair F-106 Delta Dart was a supersonic, all-weather delta wing interceptor aircraft of the United States Air Force from the 1960s through 1988. Referred to as the "Ultimate Interceptor" it was the last dedicated interceptor in USAF to date. Originally envisioned as an advanced derivative of the F-102A Delta Dagger and given the designation F-102B, the "Ultimate Interceptor", as it was known, entailed such extensive changes that in June, 1956, the designation was changed to F-106.  It was designed from the ground up as an Interceptor and nothing but an interceptor.  Originally designated the F-102B, it was re-designated the F-106 due to it's extensive structural changes and the more powerful Pratt & Whitney J75 engine.   The single seat F-106A first flew on December 26, 1956, was delivered to and entered operational service with the US Air Force (USAF) in May 1959 and achieved initial operational capability in October, 1959.  The two-seat F-106B made its maiden flight on April 9, 1958, achieved initial operational capability in July 1960, and retained the full combat capability of the F-106A.  All F-106 production ended in late 1960 with a total of 277 F-106A's and 63 F-106B's being built at a cost of about $5 million each.

The F-106 Delta Dart was manufactured by the Convair Division of General Dynamics. It's design, andthat of its predecessor the F-102A, is closely linked to Langley and the development of "area ruling" (Area Rule) in the early 1950's.  Area Rule reduces drag at transonic speeds and is reflected in the "coke bottle" or "wasp waist" shaped fuselage of the F-106.  Area ruling enabled the YF-102A to easily exceed the speed of sound and subsequently led to the go-ahead for the advanced version which became the F-106. The significance of area ruling was recognized by the National Aeronautic Association which awarded the originator, Richard T. Whitcomb, its prestigious Collier Trophy for the greatest achievement in aeronautics in 1955. It was powered by a single Pratt and Whitney J75-P-17 turbojet engine of 16,100 LB thrust (24,500 LB thrust with afterburning).

Developed as an interceptor, its mission was to shoot down other aircraft, bombers in particular. It used a Hughes MA-1 electronic guidance and fire control system. As quoted to me in an e-mail by Dick Stultz, LtCol, USAF (Ret) who was an F-106 Pilot and who "Fired simulated AIR2A in William Tell Competition without Operational MA-1", "The MA-1 NEVER had full control of the aircraft, a capability so many publications erroneously extol. The MA-1, using its data link target information or command information, would provide directives for altitude, airspeed, xyz coordinates and command directions, which would be flown by the autopilot, however, the MA-1 NEVER regulated the throttle at any time, for forward and aft movement, thus the MA-1 could never really fully control the airplane except to provide requested directions that required coupling and thrust selection by the pilot. The pilot HAD to take it off, climb, descend, and land the aircraft, every time!" The F-106 proved its ultimate performance capabilities in providing aggressor "enemy" delta-wing familiarization training to the Navy's best pilots during the time they were implementing TOP GUN. The Navy jocks learned valuable lessons that the Delta winged 106 was almost unconquerable in the dogfight arena, with guns in the air-to-air environment, which you read so little about in the Navy publications. Wing loading of 43 lbs/sq ft and a .8 -1 TWT put it in a class of its own against the A4s, F-104s, F4B,C,D, F-105, F-100, F8 fighters of its time.....not to mention the many many '14s and '15s that blew engines in attempting to fight when it took them above 40,000 feet, to a guns-only environment. Good thing they finally fixed those great fighters to handle the altitudes the 106s formerly ruled.

The F-106 also came in a 2 seat "B". Unlike other popular 2 seat aircraft, such as the F-4, the back seater in the "SIX" had the exact same control capability as the front seater. He could fly the aircraft and perform all operations from his rear seat. The F-106B also could carry the same armament.

On December 15, 1959, Colonel Joe Rogers piloted an F-106A to a World Speed Record of 1,525.695 mph (Mach 2.41). The F-106 still holds the record as the fastest single-engine turbojet-powered airplane.

The F-106 served with the USAF Air Defense Command (ADC), Tactical Air Command (TAC), and Air National Guard (ANG). The Air Force gradually retired the aircraft from active service after a long and distinguished career during the 1980s, last unit in 1988. The post Delta Dart period saw them used as drone targets during air-to-air missile training for our current generation of fighter aircraftThe with the QF-106 drone conversions being used until 1998 under the Pacer Six Program. The Six also saw continued use with many NASA projects. While there are no flyable F-106's remaining, all survivors have been de-milled with most survivors on static display in museums and parks

Mark Foxwell writes on 1 Feb 2015: "I flew several sorties in the F-106 in a full pressure suit... while we were developing new High Altitude Intercept Tactics at IWS. I had the Six above 75,000 ft." --Mark Foxwell Col USAF (Ret) Commander USAF IWS


On 11 September 1951, Convair received a contract for its delta wing design, designated the F-102. Work on the competing Republic design was also authorized, and was designated XF-103, however, the XF-103 was so far ahead of the state of the art, it was deemed too risky to be a serious contender for the 1954 Interceptor project.  This made the F-102 for all practical purposes the winner of the contest.

The USAF authorized fitting a Westinghouse J40 turbojet into the first few examples of the F-102, but production aircraft were to be powered by the 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

"Cook-Craigie" Program to Expedite 1954 Interceptor Development

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, who during the late 1940s developed a concept of an aircraft development program where the usual prototype stage would be skipped. Rather than waiting to start full-scale production until the prototypes had passed flight testing and the bugs ironed out, the Cook-Craigie plan called for delivery of a small number of production aircraft during the flight testing phase so 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, as it can produce a new combat aircraft in a hurry if everything goes right during flight testing, but can result in costly and time consuming fixes in the field if unexpected problems turn up. The Cook-Cragie plan is viable if there's a high degree of confidence that the aircraft is really going to go into production, and since the F-102 was basically a scaled-up XF-92A, the risk seemed worth taking.

From the F-102A    F-102B    F-106

By December of 1951, it was apparent the Wright J67 engine and the MA-1 fire-control system would not be ready in time, which forced the USAF to change its plans. They 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 later on. The interim version was designated F-102A, and the fully-developed advanced version designated F-102B. The F-102A would use the less-powerful Pratt & Whitney J57 turbojet, but the F-102B would retain the high-thrust J67. The F-102A would be equipped with an interim fire-control system, but the F-102B would be equipped with the highly-sophisticated Hughes fire control system under project MX-1179. Although the F-102A was considered only an interim version pending availability of the F-102B, it ran into some unexpected developmental difficulties and fell behind schedule. A lot of money originally planned for the F-102B, now had to be diverted into fixing F-102A 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 known as the MA-1) was slipping badly.  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, and the Air Force needed to consider alternative powerplants, finally settling on the Pratt & Whitney J75, which was an advanced version of the J57 used in the F-102A. The substitution of the J75 engine for the J67 was approved in early 1955. Seventeen F-102Bs were ordered in November of 1955, with their serials ranging from 56-0451 t0 56-0467. The F-102B mockup was ready for inspection in December of 1955. On 18 April 1956, the Air Force finalized the F-102B production contract of the previous November, ear-marking all 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. That prototype was serial number 56-0451, the first F-106 built and was the only aircraft to carry the 'YF' MDS designation as well as still being an F-102B.

Buzz Number Codes 'FC' and 'FE'

The first 3 F-106's, 56-0451, 56-0452 and 56-0453, were initially designated as F-102B and carried a buzz number designator as 'FC' since the F-102 designator was 'FC'. When the aircraft was redesignated as the F-106 it was given a buzz number designator of 'FE'. The buzz number designator would be painted on the fuselage, which stopped sometime in the late 1960's.

On 17 June 1956, the F-102B designation was changed to F-106A, which was in affect an official 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 due to  so many aerodynamic changes and far more advances to include a variable-geometry inlet design. In September of 1956, the Air Force specified that the F-106A would be available by August 1958, four years later than initially planned, and it had to be 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, and would 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, which were replaced in FY 1957 with leading edge slots. The "wet" wing used no fuel bladders, and fuel transfer was accomplished using low pressure bleed-air from engine into the tanks. It was thought, however combat damage, even 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 and a "coke-bottle" design. The variable-ramp air intakes were moved well aft of the nose and mounted closer to the engine, and the shape of the fin and rudder were changed with a clamshell-type airbrake fitted at the base of the vertical fin. A new undercarriage was fitted with steerable twin-nose wheels. On the first F-106s, the upper and lower rotating navigation beacon lights retracted when the aircraft went supersonic.  They were located immediately aft of the canopy in the dorsal position and immediately behind the nose wheel on the belly of the aircraft, but the retractable feature was disabled in later years. The Pratt & Whitney J75 twin-spool, axial-flow afterburning turbojet was the same engine which powered the Republic F-105 Thunderchief, and was rated at 15,000 lbs thrust dry, and 23,500 lbs thrust in 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. The wingtips changed after the 1956 built F-106's. All 1956 models has the Case 14 wing tips, while all remaining had Case 29 wingtips. The difference was the amount of leading edge camber towards the wing tips. That's why the rear of those 1956 model Case 14 wing tips had a slight upward curl. An interesting anecdote to this was in the MACH tuck region condition -- these 1956 Case 14 aircraft handled it a little bit differently in relation to the later Case 29 winged aircraft. It was Doctor Richard Whitcomb of "Area Rule" fame whom took the lead in refining the F-106's wing designs. His refinements to the wings up to the Case 29 were wind tunnel tested at Langley through many hours of development.

Electronics Package, WS-201A System - Project MX-1179

The electronics package of the projects design came first, known as the new WS-201A system. Project MX-1179 was the designation given to the 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, with the Hughes proposal consisting of an 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.

Airframe - MX-1554 Project

The airframe portion of the project was designated MX-1554.  Proposals were requested by the Air Force on June 18, 1950, and 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
  - Single proposals were made by Chance-Vought, Douglas, Lockheed, and Convair.

On July 2, 1951, the Air Force announced designs by Convair, Lockheed, and Republic had been selected to proceed with preliminary development.  All three were to proceed with their designs all the way to the mockup stage, with the design deemed most promising being awarded a production contract.  Later, the USAF deemed it too costly to carry through with three concurrent development programs, so it cancelled the Lockheed project entirely. The Convair and Republic entries were given the go-ahead to proceed. Republic's entry bore the company designation of AP-57 (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. Convair's entry was closely related to the experimental XF-92A, which Convair 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 consultation with Dr. Alexander Lippisch, who had done pioneering work in Germany on delta wing 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 wing aircraft to fly, but the F-92 project had itself been cancelled before any prototype could be built.

First Flights

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 as 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 26 February 1957. They were both powered by the YJ75-P-1 engine.

F-106A: Serial number 56-0451, the first F-102B/F-106 (YF-106A) produced by Convair at San Diego CA, on 14 Dec 1956 was trucked from Convair to AFFTC Edwards AFB CA.  On 22 Dec 1956 it began Taxi tests.  On 26 Dec 1956 it made its first flight, which included an air abort due to air turbine motor frequency fluctuations and speed boards that opened and wouldn't close.  This first take-off was performed without afterburner, which was comperable to an F-102 Delta Dagger take-off 'with' afterburner.  The 20 minute flight took the aircraft to an altitude of 30,000 miles and 0.8 Mach.

F-106B: Serial number 57-2507 was the first F-106B produced by Convair, which was also trucked from Convair to AFFTC Edwards AFB CA.  Taxi test runs were completed on 8 April 1958.  The first B model flight was made on 10 April 1958 piloted by pilot Fitzpatrick.  The first flight lasted for 50 minutes, almost twice as long as the F-106A first flight. The aircraft also reached higher altitudes and obtained faster supersonic speeds than is normal for a first flight.  Your author here can only imagine that was due largely but the fact the F-106A was already a tried and true model, which the 'B' models were so much like.

Armament and Engine

As on the F-102A, the all-missile armament was housed internally in a spacious ventral weapons bay, which 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 re-designated AIM-4E and AIM-4G respectively) air-to-air missiles. The unguided 2.75-inch missile armament of the F-102A was omitted.

Missile Bay door system operated on 3,000 psi air pressure to drive the doors open in 1.5 seconds and after the selected munitions are fired fired closed in 0.75 seconds. A main Air Flask wwas charged to 3000 psi, and the weapon system actuators worked at 1500 psi via a regulator. The cycle time on the missile bay doors however, did vary with whatever weapon(s) were being fired. The AIR-2A Genie was fastest because it was ejected from the bay (it took .23 seconds from ejection to forward motion); but could also fire either 2 AIM 4F radar missiles at a time (could NOT fire just one missile) OR 2 AIM 4G IR missles; OR Both, which fired 2 IR missles from the back set of rails first (so the IR missles would not guide on the radar missiles). Then after those rails retracted, the front set of AIM 4F radar missiles would extend, fire and retract, then the doors would close. There was also a "guts" button, as it was called, in the cockpit to close the doors if the sequence got screwed up and the doors didn't close automatically. HGavimng the doors remain open might cause STRUCTURAL DAMAGE if the rails hadn't retracted. The "guts" button would be used only with visual confirmation from another plane as to whether or not the rails were still extended.

An operations test of the entire process by maintenacne crews called a "Trigger Salvo" was quite an experiance to behold... and hear, especially for the maintenacne troop up in the Nose Wheel Well holding the gear positon switch, which simulater the gear being up (required to launch missles). This was a common test during Phase Inspections.

The Air-2A Genie rocket was carried in the rear half of the missile bay. It was powered by a 36,600 lbs thrust 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 Genie rocket was ejected from the weapons bay by gas pressure generated when 5 impulse cartridges fired on the special weapons rack, kicking the rocket down and away from the aircraft. There were 2 lanyards attached to the rocket from the special weapons rack that when pulled out of the Genie which would ignite the solid fuel motor. The AIM-4 Falcon missiles 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 and made its first flight on December 26, 1956. The second aircraft (56-0452) followed on 26 February 1957.  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-106 was divided into six phases. Phase I was conducted by the contractor, and Phase II was conducted by the Air Force. Phase II tests were 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.

Initial Speed and Acceleration Problems

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, rated at 17,200 lbs thrust dry and 24,500 lbs thrust in 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 equipped 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 (IID), was made standard starting with aircraft 58-0759. Some of the early aircraft were subsequently upgraded with IID, but many never got the vertical tapes. Initial aircraft had wing 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 to equip forty plus Air Defense Command (ADC) squadrons. However, by 1957 the delays in the F-106 program and the problems with the engine and fire control system had resulted in the necessity of a stop-gap measure of ordering other interceptors such as the McDonnell F-101B Voodoo, and the F-106 lost some of its urgent priority. For a while, serious consideration was given to canceling the entire F-106 program, or else 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 260 more 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 30 May 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 at Geiger AFB in Washington. This was five years later than originally planned, and even then, numerous problems kept the Delta Dart from being declared fully operational until 31 October 1959. The remaining 13 squadrons were re-equipped with the F-106A by the end of 1960. On 15 December 1959, 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, which beat the previous record of 1483.83 mph, set by Georgiy Mossolov in a Soviet Ye-6/3 on 31 October that same 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.

MA-1 Fire Control System

Also see MA-1 and SAGE page
The MA-1 fire control system was initially quite unreliable and was subjected to a lot of in-service modifications in an attempt to fix its chronic problems. The MA-1 system was upgraded 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 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 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. In September of 1960, due to the numerous modifications to the MA-1 fire control system made during production, a major modification project named "Wild Goose" was initiated 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 roaming AMC field assistance teams supported by ADC maintenance teams working at ADC bases. The 277th and last F-106A was delivered on 20 July 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 never intended for carrier-based operations. The F-106 had to be grounded again on 26 September 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, however, was the revision of the ejection system.

Ejection System Development

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's not clear what the B designation stood for, but pilots believed that it was so named because it resembled a bobsled. It was designed with supersonic ejection specifically in mind, and 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 James HowellNote 1 ejected safely from an F-106B piloted by Major James Hendrix on 6 June 1961.

The ejection sequence with the Convair 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. 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.

Note 1Technical Sergeant James Howell was a USAF Combat Controller on a Special Duty Assignment as a Test Parachutist located at El Centro, California. He also was part of a joint Army, Air Force High Altitude Low Opening (HALO) world record. Source: William Howell, son of Technical Sergeant James Howell, as e-mailed to the webmaster 27 June 2009

M61A1 20-MM 'Six Shooter' Cannon

The F-106A surprised everyone by having good maneuverability and showing potential as being an excellent dogfighter. There were some thought to using the F-106 for top cover in Vietnam. Among suggestions were to apply tactical camouflage, fit a clear-view canopy, and add 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 the cannon armament program, Convair issued a proposal to re-equip the F-106 with an internal cannon, an optical gun-sight, and a clear-view cockpit canopy in a program known as Project Six 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 mounted inside the missile bay providing an aerodynamic shield for the portion of the gun protruding below the missile bay and out into the air stream. 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.The gun installation was first tested 10 February 1969 on F-106A 58-0795 and subsequently on 59-092. A prototype gun-sight 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, compared to 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 idea of painting the F-106 in camouflage scheme was abandoned, when it was found that there was no significant advantage in doing so seeing as the F-106 would never go to Vietnam.In the late 1960s, the F-106 was provided with newly-designed larger-capacity under-wing external fuel tanks, often called "supersonic tanks", since they could be carried underneath the wings at any speed. They were a 360 US-gallon capacity, 50 percent larger than the previous 227-gallon tanks, and were jettison able, although this was rarely used in practice. The tanks were routinely carried on all but the shortest-range intercepts.In conjunction with the new under-wing tanks, in-flight refueling capability was retrofitted to all surviving F-106s, by retrofitting a slipway receptacle in a dorsal position behind the pilot. The first refueling installations were installed in 1967.The F-106 served mainly in the continental United States, 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 combat.

F-106 Phase-out to the F-15

Beginning in 1972, the McDonnell Douglas F-15 Eagle gradually began replacing the Delta Dart in ADC squadrons. As they were removed from Air Force active duty service, the F-106's were passed on to the Air National Guard.  The first ANG unit to receive the F-106 was the 186th FIS of the Montana ANG, based at Great Falls, taking delivery of its first planes on 3 April 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 7 July 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 also the 119th FIS, 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-engine 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 1982, and 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.

QF-106 Target Drone Program

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 shoot down 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.

Eclipse Tow Launch Project

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) using a synthetic rope. The first flight was made on 20 December 1997, and the last test took place on 6 February 1998. The tests were made to explore the feasibility of having a Boeing 747 tow an RLV known as the Astroliner to 45,000 feet, where the Astroliner would fire its rocket engines and fly into orbit. On 1 May 1998, this last flyable F-106 flew from Edwards to AMARC.

F-106B Two-Seat Model

The F-106B (Model 8-27) was a two-seat combat trainer version of the Delta Dart. 63 examples were ordered on 3 August 1956. The aircraft was originally intended as a pure trainer and was initially designated TF-102B and then later re-designated TF-106A. The designation F-106B was eventually chosen when in late August of 1956 the Air Force specified that full combat capability was to be provided for the two-seater.

To avoid the problems experienced with the side-by-side TF-102A trainer version of the Delta Dagger, a tandem seating arrangement was chosen. The two crew members sat under a large, single-piece clamshell- type canopy. The fitting of the aft seat reduced the fuel capacity removing a fuel cell, and displaced some of the avionics to the weapons bay. The external dimensions of the F-106B were exactly the same as those of the F-106A. The F-106B was equipped with the Hughes AN-ASQ-25 fire control system, which was equivalent to the MA-1 of the F-106A, and had the same armament capability, which was a quartet of Falcon air-to-air missiles plus one Genie rocket equipped with a nuclear warhead, all housed in the internal weapons bay.

Procurement of the F-106B was included in the third F-106A contract, but the F-106B definitive contract was not finalized until 3 June 1957.

The first flight of the F-106B (57-2507) was made on 10 April 1958. The first eight aircraft off the production line were temporarily designated JF-106B for flight tests. The first delivery to the USAF was made in February of 1959, however, the F-106B suffered from the same development problems as the F-106A single-seater, and was not declared fully operational until July of 1960.

The first 12 F-106Bs off the production line were initially allocated to testing, but they were eventually brought up to the standards of the rest of the F-106 fleet.  The last F-106B aircraft were completed as Model 8-32s, with improved MA-1 fire control systems, supersonic ejector seats, vertical instrument display panels, Case 29 wings with revised camber, and with provision for 230-US gallon under-wing tanks.

Production of the F-106B ended in December of 1960 with the delivery of the last two examples.

The F-106B participated in all of the F-106A modification programs, since the aircraft were so similar. Like the F-106A, the F-106B was initially powered by the J75-P-9 turbojet later replaced by the more powerful J75-P-17. All 64 F-106Bs built received Convair's new supersonic ejector seats with two-stage booms. The Convair supersonic seats were, however, replaced by Weber "zero-zero" seats later in the 1960s, however, the F-106B never received the weapons bay cannon installation.

In the field, each ADC and ANG squadron was provided with several two seat "B" models, which were used to perform combat proficiency training and checks. They were fully capable of performing normal intercept missions.

F-106's with NASA

Two F-106Bs (57-2507 and 57-2516) were supplied to NASA for use as systems development aircraft. They were re-designated NF-106B and assigned the civilian registration numbers N607NA and N616NA respectively.

F-106B 57-2516 arrived at Lewis Research Center in October of 1966 where it was assigned the NASA number 616. It was used for research and development in support of supersonic transport engine inlet design. It was later modified with two additional jet engines mounted underneath the wings. 616 was transferred to the Dryden Flight Research Facility at Edwards AFB in January of 1979, where it was renumbered 816. This plane was later loaned to Langley, where it was modified by the Langley Research Center in 1979 to evaluate the effect of lightning strikes on aircraft. In 1988, it was fitted with Langley-designed and manufactured wing leading-edge vortex flaps in connection with the Advanced Technology Fighter program. This aircraft was retired on 17 May 1991 and was the last flight having been flown on 5 March from Langley AFB in Virginia.  The aircraft is now display at the Virginia Air and SpaceCenter at Hampton.

In March of 1981, F-106A serial number 59-0123 was transferred to NASA at Langley to serve as a spare for 816.

F-106B 57-2507 arrived at Lewis in September of 1972, where it was assigned the number 607. It was used for solar cell and ocean color scanning tests, which were designed to be used in water and land quality evaluation. In May of 1981, 607 was transferred to Langley.  It was cut in half in 1984 for use in full-scale wind tunnel testing.

F-106B 59-2545 arrived at Langley on 30 January 1985, and is a non-flyable aircraft used for various tests.

F-106B number 57-2513 was used as a Rockwell B-1 chase aircraft by the San Antonio Air Logistics Center at Kelly AFB in Texas.

F-106C/D/X Models

The F-106X (Model 8-28/8-29) was a 1956 design study for a Delta Dart follow-on. With the XF-108 effectively dead, Convair attempted to modernize the F-106 design. This study envisaged an interceptor with a canard layout that was powered by a JT4B-22 turbojet fed by rectangular air intakes. It was envisaged as an alternative to the Lockheed YF-12 (later SR-71), and was to have had a fire control system with "look-down, shoot-down" capability fed by a 40-inch radar dish.  The F-106X was extremely advanced for its time with Mach 5 performance envisaged by Convair. Carried over from the F-106, the only thing would have been the basic delta design. A more powerful engine was to be mounted with redesigned intakes to account for the new engine. Canards were added on the intakes and the cockpit was raised to improve visibility. The fire control systems were to be given a complete overhaul with the AN/ASG-18 previousy developed for the XF-108.

The project was later re-designated F-106C/D, with "C" being the single-seat version, the "D" being the two-seat version.  At one time the Air Force had considered acquiring 350 of these advanced interceptors, but the F-106C/D project was cancelled on 23 September 1958. Convair got as far as mounting a new nose on an F-106 to test the practicality of the design before the project was cancelled.

Following the cancellation of the Model 8-28/29 project, two production F-106A's; 57-0239 and 57-0240, were modified to test the new radar housing with a five-foot nose extension. They were re-designated F-106C. Only 57-0239 actually flew, and made ten flights with this new nose in 1959. The plane was later destroyed in fatigue tests.  57-0240 eventually reverted to standard F-106A configuration.

F-106E/F Models

On 9 February 1968, the Defense Department announced they were not going to purchase the Lockheed F-12A interceptor (later the SR-71), opting instead to remain with the F-106 as the primary interceptor to protect the continental USA from air attack.

On 3 September 1968, Convair issued a proposal for an "improved" interceptor that was to be designated F-106E/F. It was to be compatible with the upcoming airborne warning and control systems as well as with the over the horizon radar defense network. The F-106E/F would have had a longer lose, with a new and improved radar with a "look-down/shoot-down" tracking and missile launch capability. It would also have had a two-way UHF voice and datalink radio. It would be capable of launching both nuclear and non-nuclear missiles, including the AIM-26 Nuclear Falcon and the AIM-47. Unfortunately for Convair, this project never got off the drawing board.

Foreign Customers

The Delta Dart was never exported to foreign air forces.  A pair of F-106's were displayed at the 25th Paris Air Show in June of 1963, but no customers were forthcoming. Convair tried to interest Canada in a Canadian version-not merely as in interceptor but also for the strike role. Nothing ever came of this idea. There were also plans for F-106 final assembly and production in Germany, but these plans never reached fruition. There was a proposal for an F-106 version for Japan with an MG-10 fire control system (the same one that was fitted to the F-102A Delta Dagger) and six Super Falcon missiles. It was also to have ground-attack capability, with a pair of pylons underneath each wing capable of carrying bombs or fuel tanks. The Japanese sale never took place and several years later Japan undertook manufacture of the F-4EJ Phantom.

OCONUS Deployments

The F-106 Delta Dart served primarily in the continental United States, in Alaska and in Canada, and while never permenantly assigned to any overseas location, did serve short TDY spells, deployments and special appearances around the world. The the Delta Dart however, never saw any combat.
  • Korea: Several F-106 FIS units deployed to sit Alert at Osan AB, South Korea as part of the Korean buildup to support two distinct actions of the USS Pueblo' and EC-121 Shoot-down incidents. They sat Alert following the USS Pueblo incident and to fly shotgun for the EC-121 Constellation's after one got shot down by North Korea on 15 Apr 1969. The first F-106's deployed from the 318th FIS McChord AFB on 22 Mar 1968, conducting in flight refueling en route, the first such refueling of F-106's. The last unit to serve in Korea was the 95th FIS which departed Korea on 1 May 1970. In between those dates (and units) also served the 48th, 71st and 94th FIS'.

  • Germany: September 1975, 5th FIS deployed 7 F-106's tail numbers F-106A 56-0460, 59-0005, 59-0010, 59-0015, 59-0019, 59-0063, F106B 58-0901 to Hahn AB, Germany (Europe) to participate in the NATO exercise Autumn Forge/Cold Fire '75, 4 to 27 September 1975.

  • Iceland: The 87th FIS Red Bulls deployed to Keflavik Iceland in April 1978 to assisted the 57th FIS with Alert Duties as that unit transitioned from F-4Cs to F-4Es.

  • France: Two F-106's deployed from the 48th FIS for displayd at the 25th Paris Air Show, June 1963.  F-106A 59-0136 was on display, while F-106A 59-0124 was the spare.

  • Panama: Spring 1974, 318th FIS deployed F-106's to Howard AFB in the Panama Canal Zone for Exercise Blackhawk '74

  • Canada:


  1. History of the Convair F-106 Delta Dart, Joe Baugher Research
  2. General Dynamics Aircraft and their Predecessors, John Wegg, Naval Institute Press, 1990
  3. The Illustrated Encyclopedia of Aircraft Armament, Bill Gunston, Orion, 1988
  4. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989
  5. The American Fighter, Enzo Angelucci and Peter Bowers, Orion, 1987
  6. Fighters of the United States Air Force, Robert F. Dorr and David Donald, Temple Press Aerospace, 1990
  7. American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday, 1982
  8. Post-World War II Fighters, 1945-1973, Marcelle Size Knaack, Office of Air Force History, 1986
  9. The World Guide to Combat Planes, William Green, MacDonald, London, 1966
  10. The World's Fighting Planes, William Green, Doubleday, 1964
  11. The Aircraft of the World, William Green and Gerald Pollinger, Doubleday, 1965
  12. F-102 Delta Dagger, Benoit Colin, Combat Aircraft, Vol 1 No 3, September 1997
  13. Mancus, Peter, "Red Alert: The F106 and the Case for Manned Interceptors," Wings, June, 1981 (magazine article).
  14. (Author unknown), "Flying the 'Six" Air Force Magazine, October 1973 (magazine article).
  15. Tokunaga, Katsuhiko, "Dart Out," Koku Fan Magazine, (issue & date ?--magazine article)
  16. "The History of the Air Force Flight Test Center," Chapter 15, July-December 1957, Vol 1. (official USAF history publication, Edwards Flight Test Center)
  17. Gamble, Maj. Gen. Jack and Capt. Patrick K. "Convair's Deadly Delta," USAF-USN Jet Fighters, 1988 (magazine article)
  18. (Editors), "FANG: We Fly with the Convair F106s of the Florida Air National Guard", Air Combat Magazine, (1985?-magazine article)
  19. Peacock, Lindsay, 'Aircraft Illustrated’, (magazine article, date & issue unknown)
  20. Detail & Scale Publications: "F102A Delta Dagger" (illustrated book)
  21. Detail & Scale Publications: "F106A Delta Dart" (illustrated book)
  22. Dabrouski, Hans-Peter, "Lippisch P13A & Experimental DM-I," Schiffer Military History, Volume 67, Atglen, Pennsylvania, 1990 (illustrated book)
  23. USAF Technical Order 1F-106A-23
  24. USAF Technical Order T.O. 1F-106A-2-1 General Airplane
  25. USAF Technical Order T.O. 1F-106A-2-3 Hydraulic & Pneumatic Power Systems
  26. USAF Technical Order T.O. 1F-106A-2-6 Air-condtioning, Anti-icing and Oxygen Systems
  27. USAF Technical Order T.O. 1F-106A-01 List of Applicable Publications
  28. USAF Technical Order T.O. 1F-106A-1 Flight Manual
  29. USAF Technical Order T.O. 1F-106A-CL-1-I Pilot's Checklist
  30. USAF Technical Order T.O. 1F-106B-543 Ejection Seat. Weber
History - Encyclopedia USAF Aircraft-Missile Systems (AFD-100526-027) F-106 Delta Dart
Convair F-106 Development History by Christopher T. Carey (Life Support Historian, McClellan Aviation Museum)

HISTORY of the Convair F-106 Delta Dart Interceptor by Christopher T. Carey

Life Support Historian, McClellan Aviation Museum


The period of American aeronautical engineering innovation which characterized the two decades following the end of the Second World War was one of great significance to the history of American military aviation. From 1945 through 1965 many notable aircraft designs emerged from the project rooms of the major US aviation firms of the Lockheed, North American, Republic, Bell, and Convair (Consolidated- Vultee) companies. The advanced fighter aircraft that ultimately took shape and were flight tested during these years at the Edwards Flight Test Center in California's Mojave Desert were in many cases considerably influenced by exhaustive evaluation of captured German aeronautical research performed both before and during the war years (1939-1945).

Today, many knowledgeable individuals and aeronautical historians consider these two decades of American aviation development as the modern Golden Age of US aeronautical design. Chief among the machines produced in this era were the so-called Century Series fighter aircraft. These were fighter aircraft with designations in the 100 series, and included the North American F100 Super Sabre, the McDonnell F101 Voodoo, the Convair F102 Delta Dagger, the Lockheed F104 Starfighter, the Republic F105 Thunderchief, and the Convair F106 Delta Dart.

Of all of these, perhaps the most interesting and enduring of these aircraft was the spectacular Convair Delta Dart, a high performance, dedicated aerial interception airplane configured with delta wing design and capable of sustained Mach II flight. Curiously, whereas such aircraft as the Lockheed Starfighter are well known around the world, the Convair F106A remains possibly the most important and yet least known of the jet age Century Series aircraft produced after the war.

To view the Convair Delta Dart sitting silent and still on the ramp is to immediately recognize the beauty of its clean design--a design that cries out speed and performance. To fly it is to fall instantly in love with the 24,038 pound (empty weight; gross weight was 39,195 pounds) gleaming gray beast. It is no wonder that pilots who were privileged to accumulate hours in the Six, as it was commonly referred to, found that their wives sometimes suspected that their relationships with their F106 pilot husbands were somehow less intense than the affair the typical Six pilot carried on with his sensual delta winged marvel.

The Convair F106A interceptor has now passed out of the active inventory of first line American aircraft, the last units operated by the American Air National Guard having relinquished their aircraft in late 1988 to the Davis-Monthan Air Force Base Aircraft Maintenance and Regeneration Center (AMARC) in the dry Arizona desert. While it served as our primary air defense interceptor, first with Air Defense Command and finally in service with Tactical Air Command (an amazing span of almost 30 years of service), it justifiably captured the imagination of just about every pilot who ever had the good fortune to fly the bird. It is further remarkable to note that in all of its extensive service life throughout the "Cold War" era as the principal US area defense aircraft, it never fired an angry shot in a war action (unlike its immediate predecessor, F102A, which saw limited service in Vietnam).

With the retirement of the last operational F106A Delta Dart in 1988, the 277 single seat and 63 two seat versions (F106B) were converted into remotely targetable drones for use as high performance weapons test vehicles under the "Pacer Six Program." At this writing, the QF-106A &. B drones have been entirely replaced by the QF4C Phantom II drones, and the Pacer Six Program is officially history. The few survivors of Pacer Six have largely met their final fate. Most were destroyed in weapons tests at Holloman and Tyndall air force bases, although some severely damaged specimens were unceremoniously dumped into the Gulf of Mexico, where they serve as artificial fish reefs. A handful (about 6 in number) were sold to civilian concerns (notably to David Talof's GrecoAir in El Paso Texas), and two dozen or so have been consigned to various aviation museums around the nation.


The story of the Convair Delta Dart really begins back before Second World War, with the historic aeronautical designs of Germany's Dr. Professor Alexander M. Lippisch. Lippisch was one of the earliest proponents of delta-winged tail-less designs (sharing that vision of the advantages of the delta concept with the Horton brothers), and in the early 1930s had already begun design studies of a number of delta designs. One of these concepts (the DFS 39) later took form as the Messerschmitt Me163 Komet, a rocket powered point-defense interceptor that, although it came too late to significantly deter the massive saturation bombing of the German homeland, pioneered entirely new parameters in advanced aircraft design and pointed the path to the future.

Among Dr. Lippisch's advanced concepts was the idea of combining the delta platform with a ramjet propulsion system; in the late years of the war his researches anticipated a progressive series of delta-winged ramjet powered supersonic aircraft, each capable of higher and higher performance capabilities, through and into the hypersonic region of flight.

In particular, the Lippisch Project 13A (or P13A) was a design for a 960 mph, ramjet powered fighter aircraft weighing approximately 5060 pounds, capable of reaching altitudes of nearly 64,062 feet. It was to test the flight characteristics of the projected P13A aircraft that a near full scale, un-powered test model was constructed, known as the Lippisch DM1. A subsequent series of three powered supersonic experimental aircraft were to follow, the final DM4 being capable of more than 6,000 mph! A conventionally powered (Focke-Wulf 58) launch aircraft was to have been used to carry the research vehicle "piggy-back" to a sufficiently high altitude to allow the ramjet powerplant to be tested, in a manner not too dissimilar to the system used to conduct initial (un-powered) flight testing of the first American space shuttle.

Due to the final ravages of the Allied air war against Germany, the DM1 test glider was not yet completed when it was captured by American forces in 1945. Fortunately for American aeronautical researchers, the advanced nature of Dr. Lippisch's design was recognized, and largely due to the urgent prompting of renown aeronautical scientist Dr. Professor Theodore von Karman (under the auspices of the American Air Force Scientific Advisory Group. or SAG), the DM1 experimental test glider was authorized to be completed by Lippisch group engineers in Germany under American supervision.


Shortly thereafter, however, a decision was made to bring Dr. Lippisch and his DM1 test model back to the United States, rather than conduct flight studies in occupied Germany. The DM1 was exhaustively analyzed and tested by the NASA-precursor body, the National Advisory Council on Aeronautics (NACA), in 1946. This rigorous examination of the design in Langley wind tunnels led to a series of 8 major changes being made in the basic DM1 design that explored the characteristics of delta wings and provided an initial analysis of the potential for delta- winged supersonic flight. By the time NACA was through with the Lippisch DM1 it was almost unrecognizable, but much valuable information had been obtained which would provide a comprehensive basic database for the American delta-wing fighters to come.

At this time, immediately after the end of the Second World War, it was becoming clear to a number of military and political elements within the United States that the threat of growing Soviet military power would constitute the most urgent future focus for US defense research in aeronautical design. Specifically, in recognition of the role that strategic airpower would play in any future conflict, the continuing need for development of an advanced fighter interceptor was officially acknowledged by the US Air Force, which had earlier canceled 1945-46 experimental interceptor projects due to post-war demobilizations. As evidence that the Soviet Union was interested in building a massive strategic air force continued to mount, new concerns evolved with regard to America's ability to intercept and deflect future Soviet strategic bomber forces, since Stalin gave every indication of wishing to match America's post-war strengths in bomber technology.


The US pioneering aviation firm Convair, formerly Consolidated-Vultee, was an early US advocate of the delta wing planform for supersonic and hypersonic flight. Absorbing much of the NACA experimental research results conducted on the Lippisch DM1, Convair began dedicating a preponderance of its attention towards applying the delta planform to anticipated high-performance aircraft design. In 1945, subsequent to a conference attended by Convair, the US Air Force, and Dr. Lippisch, a determination was made that a new and considerably advanced interception aircraft, utilizing Dr. Lippisch's theoretical concepts, was needed; consequently, a contract was awarded to Convair for the development of a new experimental supersonic fighter aircraft under requirements of Air Force Project MX-82. The design that resulted, designated by Convair as Model 7002 (known as the "Seven Balls Two" to project engineers and soon to be identified as the US Air Force XP-92) took early form on the drawing board as a ramjet powered delta- wing aircraft with the pilot's cockpit placed inside the forward end of the ramjet intake tube. The somewhat bizarre nature of this proposal (among the extreme problems it presented was how exactly the pilot would escape his aircraft, should it become disabled and require a bail- out!) soon became recognized and a decision was made to utilize a more conventional turbojet and rocket propulsion system, after it was determined that the combination of advanced delta design and ramjet propulsion in a single test vehicle was pushing the limits of then state-of-the-art technology too far. Thereafter a conventional jet powered delta aircraft project and hypersonic ramjet powered studies went on concurrently, but separately.


After a number of tests and simulations were carried out with models of the proposed design mounted on rockets, the final design for a turbojet powered delta design was configured and designated the Convair XF-92A The XF-92A was fitted with a then typically underpowered turbojet engine initially, and somewhat later with a more powerful afterburning engine. Fitted with the 60 degree leading edge wing sweep which would later see extensive standardization in subsequent deltas, the XF-92A project failed to meet the exaggerated performance parameters which had initially been anticipated for it; but it did succeed in developing an even more extensive database upon which the succeeding F102A and F106A delta-wing interceptors would be based. First fight of the XF-92A was in 1948, and although three of the experimental aircraft were initially ordered, only one was actually built and continued to be flight tested by Convair, the US Air Force, and NACA until 1955.

Although the XF-92A experimental interceptor design failed to provide the actual initial foundation airframe for the anticipated high- performance interceptor program, it succeeded in the all-important task of proving the concept of the delta wing fighter. As such, it remains a significant and historical ancestor of the final, perfected F106A Delta Dart, and is an important link in the chain of events that gave rise to the ultimate interceptor' that was the Six.


In 1941, the US Air Force formally identified the urgent requirement for an advanced pure air-to-air weapons system, capable of meeting the threat posed by Soviet long-range bombers. Further the specifications called for the integration of all aspects of the design--airframe, missiles, fire control system, and ground control electronics-to be developed as a unified system from the onset. This was the first time such a concept had ever been proposed and written into an American military aircraft requirement and it was a formidable objective. Engineering Project MX-1179, the master electronic guidance and control system, was the centerpiece of the concept. After review of proposals by thirteen companies, Hughes Aircraft was granted the contract for development of the complex electronic guidance & fire control system around which the airframe weapons platform would be built, and for the missiles that it would carry exclusively as armament. Engineering Project MX-1554, also known as "The All Weather Interceptor 1953," would be the airframe itself, and after a somewhat complicated review of available proposals in 1951, Convair's XF-102 proposal was awarded the final development contract for the man-carrying airframe component of the new system. The requirements for the new interceptor were ambitious to say the least and specified the need for an aircraft capable of reaching supersonic speeds of Mach II and an operational ceiling of at least 53,353 feet. All of this integrated system was envisioned as being completely flight tested and ready to start active service by 1954�a very optimistic outlook, to say the least!

As was soon seen, considering the early state of the art in "advanced" jet propelled aircraft at the time, the expectations for a pure interceptor aircraft capable of this sort of extremely enhanced performance were not fully realistic. Much had yet to be done to explore the potential of both aeronautical airframe design and powerplant combinations which would prove suitable for the successful aircraft, and there were many areas of uncertainty in all areas of the project's systems which needed to be resolved before the program would bear fruit.


Although the Convair proposal was now in the works, the Air Force was not fully convinced that Convair's projections on the drag aspects of the F102 delta design were accurate, and in fact Clarence Kelly (chief of Lockheed's design section) went on record as stating that the delta design was not as superbly suitable for high-speed flight as was supposed (one of the few occasions when Kelly got it wrong!). Thus it was that when the first flight of the new Convair YF-102 took place in October of 1953 at Edwards Flight Test Center in California, it became rather quickly apparent that the proposed F102 design would not achieve the ambitious flight performance levels being sought after for the Air Force's Ultimate Interceptor'. Consequently, the requirement was changed to allow for what would be termed an interim interceptor design (the F102A), to be followed somewhat later by the definitive, very high performance ultimate interceptor version, initially designated the F102B.

The first pre-production YF102 Delta Dagger (known by its crews simply as The Deuce') flight test prototypes were indeed found to be far from perfect and chief among the faults of the design was the YF102's embarrassing inability to exceed the speed of sound in level flight (the best it could achieve was Mach .98 and 50,918 feet ceiling). This was due largely to problems with transonic drag that combined with available engine thrust insufficiency to prevent sonic penetration. Although the Bell XS-1 research rocket had in 1947 famously blasted its way through the sonic barrier by sheer force alone, available turbojet designs were not then powerful enough to overcome the drag defects in the initial F102 design: it was only after the fuselage's proportions had incorporated changes specified by NACA aeronautical scientist Richard Whitcomb`s Area Rule that subsequent versions (designated the YF102A) were able to achieve the sought after interim interceptor performance specifications. Supersonic wind-tunnels were still not available when the bulk of the Convair studies had been done in the late 40s, and the somewhat portly YF102's drag problems were seriously compounded by a lack of sufficient engine thrust, a characteristic problem associated with early jet engine developments of the immediate post-war period. Together, these two obstacles resulted in the original YF102�'s failure to meet expectations.


The Air Force had justifiable reservations about the Convair design by this time, and it was only fast and dedicated work by the Convair design team which turned what appeared initially to be a near failure into an acceptably near success. Since the US Air Force was considerably displeased by this shortcoming, Convair's contract was in jeopardy. Therefore, a major reworking of the entire airframe was immediately undertaken and within 117 days of almost non-stop work, the vastly modified F102A took shape. The modifications were so extensive that a visual comparison of the two airframe designs (compare diagrammatic profiles of the YF102 and the YF102, found elsewhere in this paper) instantly reveals the extent of the changes wrought in the original YF102 to achieve more reasonable performance parameters.

Additionally, the Hughes Aircraft fire control system planned for the��1954 Interceptor' had also lagged in development, and as a result it was only after extensive work that the Hughes integral fire control system was sufficiently developed and re-engineered to incorporate it into the considerably reworked YF102A airframe.

Thus only after extensive, protracted testing and development of the original components of the "weapons system" that the F102 and Hughes fire control components together comprised, did the final standard F102A configuration take to the air in mid-1955. In mid-year of1956 the first production F102A became operational, carrying the early Hughes MG-3 fire control system, along with the (AIM-4) GAR-1 Falcon air-to-air missiles that were initially its sole weapons. The final F102A aircraft proved to be a Mach 1.22 capable aircraft with a combat ceiling of 55,692 feet. Further, with an airframe limit of Mach 1.5, the F102A airframe proved itself unsuited as the basis for development of the enhanced ultimate interceptor' (still designated the FI 02B, and not yet as the F106A).

The aircraft that entered service as the "interim interceptor" (F102A) was considerably larger and heavier than the original specifications had called for in 1951. This was due to the radical alterations that had been necessary to perfect the original subsonic YF102 airframe. Changes contributing to extra weight included extensive lengthening of the fuselage, modifications to the wing (camber changes to augment lift coefficient and reduce drag), canopy and air intakes, and of course the reshaping of the F102A fuselage to comply with "area rule" calculations. Nevertheless, when the final production F102A was introduced in quantity in 1956 and 57, it was an adequate interim interceptor. In 1958 the initial MG-3 airborne fire control system was upgraded to the more advanced Hughes MG-10 development, which further enhanced the system's seek-out and shoot-down capability. Armament eventually included both the GAR-1 missiles and 2 (diameter) inch rockets stored in the leading edges of the missile doors, which were a back-up system to employ, should the GARs fail to take out their target.

A note in passing warrants brief mention here: when the F102 was still in service test, the Stanley Aircraft Company (later famed for its egress systems) proposed a fully encapsulated pilot escape module, which it hoped to develop for all of the new Century Series aircraft. Although a working model was never built, and the F102 had a conventional ballistic ejection seat installed, the Stanley Company did go on to pioneer many innovative egress systems of the 60s and 70s (including the encapsulated crew module used in the Convair B-58 Hustler Mach 2 bomber).


The Hughes integrated weapons system, which the aircraft weapons, guidance electronics, and missile armament comprised, was directed by what was termed the SAGE ground controller (also known as NAGE in Europe). Initial detection of hostile airspace intrusion and guidance to the intercept target for the F102 and its MG-10 targeting and fire control system were provided by verbal link (later in 1965 by digital data link) through the Semi-Automatic Ground Environment controller complex. Although conceptually configured for fully automatic flight control from the ground, the F102A system was never quite completely capable of this advanced design objective. In theory the SAGE system would scramble the aircraft and guide the fighters to the initial interception, whereupon the on-board MG-10 system would then automatically select the target, lock on, and fire the missiles. The Hughes GAR-1 type missiles were of both infrared and radar semi-active homing types and once lock-on was achieved, the kill was virtually assured. In actual service, pilots flying the F102/MG-10 system would confirm the fact that the operational ideal fell slightly short of the intended goal, although the end result was quite near to meeting what the Air Force had anticipated for its interim interceptor specifications. Although adequate in the short haul, the early result of the Air Force's advanced interceptor project was still somewhat less than what had been envisioned and anticipated.

In combination with North American Air Defense Command's Distant Early Warning (DEW line) detection radar arrayed in the polar regions of North America, the SAGE-directed F102A/MG-10 weapons system was indeed an adequate temporary air defense system against Soviet bombers. However, with aircraft development increasing ever onwards on both sides of the so-called Iron Curtain the need for the successor to this system initially designated the F-102B (or the Ultimate Interceptor'), was keenly felt.

Although the service life of the interim F102A interceptor was relatively brief, more than 600 of the type were eventually built (as opposed to over 310 of the subsequent and definitive F106A & B models) and found service use in several foreign nations, as well as in the US Air Force.


As events had developed in the early 50s (with the early indications showing that the F102A was still not the hoped for ultimate interceptor', progress was maintained towards developing the advanced version of the interceptor, concurrent with the F102A (interim) program. As has been previously mentioned, the final product of the Convair interceptor project was to have been designated the F102B, but as work continued it became clear that the ultimate interceptor product would be so radically enhanced and improved as to be almost an entirely new aircraft design in its own right. Therefore, in 1956 the advanced F102B ultimate interceptor' version was formally re-designated F106. Benefiting from all the simultaneous developmental research and flight testing of the F102A project, the new ultimate interceptor' took shape far more quickly than its predecessor, and in December of 1956 the initial prototype F106A first flew from Edwards Flight Test Center, coming quite close to the US Air Force requirements of Mach 1.9 and an operational ceiling of 57,000 feet. It quickly gave promising early evidence of being everything the US Air Force had hoped for in an advanced, pure interceptor aircraft.

About two years after the flight testing had begun on the single seat F106A version, the two-seat F106B version was introduced at Edwards Flight Test Center. Both variations were studied and evaluated for several years subsequent to this at the desert air base in continuing Phase Two Flight Test programs.

Chief among the improvements incorporated in the new F106A aircraft were a much higher rated engine (the General Electric J-75), capable of putting out 15,984 pounds of thrust at full military power (24,000 pounds of thrust on full reheat), relocated and much modified variable-ramp air intakes, and the very advanced Hughes MA-1 Fire Control System (a major step-up from the F102A's MG-10 system). The most obvious change in the new design was the elegant, slim and aerodynamically perfected fuselage that unlike the F102 predecessor had benefited by having the Area Rule theory incorporated in its construction from the onset. Also notable were the truncated tail fin (interestingly, despite the change in the vertical fin shape, the area of both the F102A and F106A fins remained the same) and the newer, more streamlined canopy design.

Aside from the inherent beauty of the F106A with its aerodynamically "clean" design that enclosed its ordinance internally in fully enclosed weapons bays, the new pure interceptor design was an exceptional performer right from the start. Finally, by the end of the 50s, the US Air Force had the long sought after ultimate interceptor' it had anticipated in the late 40s. The first F106A squadrons became operation with the US Air Force in May of 1959, and the production aircraft were quickly pressed into service with Air Defense Command on area defense duty in overall coordination with NORAD command and control. This was the beginning of nearly 30 years of excellent service in the air defense role that the F106A would deliver. The dawn of the F106A Delta Dart era had finally begun.


When the Dart (or "Six�) was new, it was something of a marvel to fly. Aside from its high performance flight envelope capabilities that made it a challenge to pilot, it was an extremely deadly and effective weapons system that any hostile airspace intruder had reason to fear. The heart of its deadliness was the advanced MA-1 airborne fire control system, developed by Hughes Aircraft and based upon the earlier F102A MG-10 system. Comprised of over 2512 pounds of navigational and fire control electronics, the MA-1 system's 200 separate black boxes full of hollow state devices' (vacuum tubes) formed a very formidable all-weather, fully automatic weapons suite for its time. While technologically obsolesced by today's state of the art aircraft guidance and control systems, the MA-1 system nevertheless represented the apex of contemporary aerial targeting and fire control systems of its day.

Due to advancements in SAGE and on-board data transmission links, it was fully capable of completely automatic interception and destruction of designated targets, as well as blind GCA and ILS flight in all categories of weather. In such a mode, the pilot was almost a redundant component! In the course of its development, the electronics (originally utilizing vacuum tubes in its black boxes) underwent continuous upgrading and improvement as solid state (transistorized) devices became the norm. There were, however, circumstances in which a human computer' on board was handy (such as in conditions involving fully automatic digital data link intercepts under unusual or divergent jet- stream and target heading situations), but no real Dart pilot worth his stuff would ever admit to the contrary, in any event!

It is worthwhile here to take a moment and examine a few of the characteristics & parameters of the F106A Delta Dart. With a fully loaded flight weight of over 40,992 pounds, a wing area of 705 square feet, and a single axial flow Pratt and Whitney J-75 turbojet engine rated at 24,000 pounds of thrust on full reheat, the F106A was a spectacular performer. If there was any criticism of the aircraft by its crews it was that it was hard to slow it down, for the aircraft liked to keep fast company. Zoom climb altitude was 74,255 feet, and normal service ceiling was 60,466 feet. Maximum maneuvering speed was Mach 1.9 at 42,431 feet. The length of the Six was 75 feet; its wing span was 40 feet, and its aspect ratio 2.2. Maximum speed was officially specified as Mach 2.31 at 42,431 feet altitude. Empty weight was listed as 23,695 pounds, while maximum take-off weight was given as 38,330 pounds. With two supersonic-rated external fuel tanks, each holding 360 gallons of JP4, maximum range was listed as 2,684 miles at 606.5 mph airspeed and 43,819 feet altitude, while combat radius was 572 miles with internal fuel only. Useable fuel load carried internally in the A model was 1740 gallons of JP4, stored in 8 wing tanks and one fuselage tank located behind the cockpit. Standard interception armament consisted of a combination of AIR-2A or AIR-2G Genie Nuclear Rockets, AIM4E/4F Super Falcon radar guided missiles, AIM-4G Super Falcon infrared seeking missiles, and an internally fitted General Electric M-61 20mm multi-barrel cannon with 75 rounds of ammunition (fitted only to some models later in the aircraft's development and which replaced the nuclear-tipped Genie rocket in the weapons bay).

One of the chief concerns arising with the new generation of supersonic aircraft of the Century Series, and particularly with the new Convair F106A was the need for a new generation supersonic-rated aircrew ejection seat system. The seat used in the F102A was limited in that it was not supersonic rated, nor was it useful in zero (altitude)-zero (speed) situations. In October of 1957 a requirement for a supersonic ejection system was issued by the US Air Force, which resulted in the ICESC Seat Program (Industry Crew Escape System Committee). Convair, under the supervisory administration of the ICESC, undertook primary development of a new seat that was to provide emergency escape for aircrew in all situational parameters, including supersonic and zero-zero ejections.

The ICESC Seat Program involved over 6 years of extensive testing (1 January 1956 through 30 June 1961) of the resulting Convair / ICESC "B" Seat system on rocket-powered sleds at Edwards Flight Test Center and Holloman AFB in New Mexico. These tests ultimately culminated with a live ejection test using a human volunteer at the White Sands missile test range in New Mexico. TSgt. James A. Howell ejected from a specially instrumented F106B aircraft at an altitude of 23,336 feet, and traveling at 497 mph. The seat, which employed a unique tilt-articulated, rocket boosted system, was installed in the early serial block F106A aircraft. Sled test ejections with dummies were run at speeds simulating Mach 2.5 at 9,700 meters altitude, with statistically satisfactory results. Additionally, 35 human test subject sled runs were concluded, verifying that ejections up to 560 mph airspeed were within the range of human endurance. The "tilt-seat", as some life support people came to know it, was not entirely satisfactory, however, and after several fatalities were sustained during actual in-flight emergency ejections in the supersonic rated tilt-seat, it was replaced in the F106 aircraft by a more conventional, rocket-powered seat made by the Weber Corporation (this seat was known simply as the "Weber Seat"), from 1964 through 1967. The Weber seat remained in the F106A & B type aircraft throughout the rest of the type's service life, and gave a satisfactory zero-zero escape capability, as well as a satisfactory high-speed ejection performance for almost all emergency aircrew escape situations. It should be noted that one of the motivations for replacement of the imperfect supersonic tilt-seat' with a conventional, rocket ejected seat stemmed from a gradual de-emphasis on high altitude, high speed parameter ejection capability, as actual operational experience had shown that most in-flight emergency ejections took place at much lower altitudes and slower speeds.

Another interesting aspect of the F106A advanced interceptor was that as originally designed, the first two prototype aircraft assigned to Edwards flight Test Phase Two evaluations were fitted with what would have been the first side-stick controls in an American military jet. Due to combined Convair / Air Force evolutional consensus, however, the prototype F106A aircraft were retrofitted with conventional center-stick controls (as were the subsequent production aircraft) prior to the start of the Phase Two (Air Force operational flight test) testing, and it was not until the introduction of the General Dynamics F16 Viper' that a side- controller stick became a standard military jet cockpit feature. As in other of its advanced design areas, the early form of this unique aircraft's control system was an expression of forward thinking, and had to be marginally conventionalized for practical purposes.

As with the earliest F102 interim' interceptor, the 60 degree leading edge wing sweep was kept and used just as had been called for in the original Lippisch experimental studies. In 1958 and 1959 the two-seat, air defense capable version of the Dart, designated the F106B, was delivered to Edwards Flight Test Center and following extensive testing, approximately 63 of these two-place aircraft were subsequently manufactured and used principally for training purposes (although they could be configured with the same weapons as the single seater and used for air defense, and performance specifications for both models were essentially identical).

By 1962 US Air Defense Command had 251 of the single seat F106A models, assigned to 14 squadrons in strategic sites around the perimeter of the United States. Although superbly suited to its primary area air defense role against strategic bomber penetration, by the late 60s it became apparent that there was a need to confer point-defense and general theatre air-superiority capability upon the F106. In view of its ability to engage in air-to-air refueling with world-wide deployment now possible, there was an increasing likelihood that it would come into contact with hostile fighters in some future conflict that took it out of its nominal pure interception environment. Thus a 20 mm M-61 Vulcan rotary barrel cannon was specially configured for use by the Six, the bulk of which could be carried within its internal weapons bay. The Vulcan equipped Dart was nicknamed "Six-shooter," and new training and tactics subsequently demonstrated that the venerable F106 Delta Dart was also quite well suited for use in its new air superiority role. Part of the Six-shooter modification included a new and very accurate "snapshot" gun-sight, and the installed Vulcan M-61 cannon could be carried and used with no interference to deployment of the normal load of Super Falcon missiles carried in the internal weapons bay. Among further refinements engineered into the Six was a cockpit heads-up display, an arrest barrier tail-hook, a clear bubble canopy' hood, and improved variable ramp air inlet ramps. F106 cockpit improvements included installation of advanced vertical tape' instrument displays, proven far superior to conventional "round-eye" (analogue) instrument gauges for conveying precise data quickly.

Further, over the course of its long service life, improvements in solid- state electronics provided welcome weight reductions in the massive and complex MA-I guidance and control system components, and which also reduced lengthy maintenance requirements substantially.


Ask any pilot who has piloted the Six and he will quite readily tell you that it was one of the best aircraft he had ever flown. In typical delta-winged control configuration (equipped with elevons' instead of horizontal stabilizer and elevators), the Six felt much the same as any conventionally designed aircraft in flight, according to Six pilots familiar with other conventionally winged aircraft. The Six handled well at low speeds as well as high ones, even when operating at or near specified minimums. General flight characteristics of the Six fitted with the supersonic rated external fuel tanks are essentially the same as in clean' configuration, except that control at lower speeds is somewhat more demanding. Advantages of the delta wing with its high surface area included excellent performance at high altitudes, and agile turning ability at intermediate and lower altitudes. Furthermore, the Six was a straightforward and "honest" aircraft when flown within the parameters of its flight envelope. As with any advanced high-performance aircraft, however, flying beyond the envelope could occasionally become a hazardous undertaking. An indication of the structural integrity of the airframe was to be found in the fact that the original fuselage airframe lifespan of about 4,000 hours had been doubled, with no indications of its exceeding its lifetime limitations ever having been reached, in extensive ongoing structural testing.

Pilots flying the Six have described the plane's commendable feather light pitch responsiveness and its approach to a stall as being straightforward with progressive light, medium, and heavy buffeting leading to well indicated lateral instability that induced nose yaw. Any increase in angle of attack beyond the critical limit at this point and adverse yaw induced by any aileron input initiated a violent roll & pitch- up condition known as post-stall. The next step beyond this was a severe oscillation about all three axes and the likelihood of an imminent flat spin. All of these responses were predictably clear, and more than enough progressive warning of exceeding the flight specifications was given. Checks on the Six were a Mach 2 restriction, a 752 KIAS "Q" limit, and a skin temperature limit (the "AM3 gray" color that the Sixes were painted was to protect the skin from effects of high temperature, and was not solely for aesthetic effect).

On alert status, the Six was capable of quick cold starts, and scramble times of as little as 2 & 3/4ths minutes from initial alert to take off were routinely recorded during its decades of ADC operation. Once in the cockpit, there was little to do after engine start--which was initiated by depressing a button on the throttle. 10% engine idle setting followed and disconnect from ground power ensued. As soon as the generators were on line and the radar was display-configured, the aircraft was ready to taxi, after a last chance' look-over from the ground crew on the verge of the active runway.

Engine run-up and last minute checks for engine performance indications took place; flight controls were checked, nose wheel steering positively engaged and then brakes were released for takeoff. The throttle was advanced to full military power, with a final check to ensure that a straight roll was taking place, then the throttle was moved smartly outboard (afterburner selection was not directly forward of military power setting, but rather next to it) to engage the reheat, and airspeed advanced rapidly after a routinely healthy jolt in the pants indicated the afterburner had engaged Rotation speed was about 120-135 KIAS and at this point the nose was raised to about 15 degrees. Taking care not to exceed 17 degrees vertical (to keep the tail from scraping); you let the aircraft fly itself off the runway. The Six became airborne at about 184 KIAS, and at 250 KIAS the reheat was chopped and the aircraft accelerated to 400 knots for the climb out, keeping the rate to .93 Mach. This speed was maintained for subsequent climb-out and cruise under normal conditions.

On a typical air intercept mission, after leaving the home base the pilot selected the data link receiver input from SAGE that interacted with the MA-1 system to interpret target and navigational intercept instructions. Under automatic control the aircraft was then flown to the predetermined interception point. Verbal control communications were not necessary, and the MA-I system interacted with the aircraft in that the aircraft "told' the MA-1 system what it was doing and the MA-I system told the aircraft what it ought to do to carry out the intercept properly. A consensus in the ensuing dialogue resulted in appropriate automatic vectoring to the target.

Once the intercept point had been reached, and the target displayed on the radar screen as a blip, the pilot then used the left half of the unique U-shaped control stick to lock the target on the display. As soon as the lock was achieved by bracketing the scope blip with a "gate", the MA-I system took over; after pre-selecting the weapons to be used, the pilot allowed the MA-1 to determine the successful fire and release point to ensure a kill.

Anticipating interception of Soviet nuclear armed bombers, the Douglas AIR-2A Genie nuclear tipped rocket was carried by the F106A for destruction of such formidable targets in the first decade of the Six's service. The typical Genie launch was carried out in a characteristic looping maneuver that released the missile and allowed the Six to get as far away from the anticipated blast as possible, so as to avoid being cremated in the ensuing melee. Since the small but effective nuclear warhead of the Genie did not require precise guidance to a direct hit, in order to ensure destruction, the missile was guided to within a predetermined kill radius of the warhead and summarily detonated Somewhat later, the effective but messy Genie was retired from active use as the Soviet nuclear bomber threat diminished in proportion to the growing Soviet intercontinental missile threat of the 70s.

Once an interception had been made and missiles released, with the fast-acting bay doors snapped closed shortly after firing, the Six was brought back to home base either under manual or fully automatic control via the SAGE control center. If desired, the aircraft could be brought in, finaled, flared and landed--all under automatic control and in full Category 3 conditions, if need be.

Back home, initial approach was flown at about 325 knots. Break was carried out clean, rolling out on the downwind at about 1591 feet altitude, with landing gear lowered at about 250 knots (gear retraction was mandated on takeoff before reaching 280 KIAS to avoid damage, as acceleration was so great with reheat that this was quite easy to exceed). Landing approach speed of 180 knots was usual, and characteristic increased nose-high attitude resulting from delta-wing speed bleed-off was easy to misjudge without prior delta wing experience. Resultant loss of altitude could occur rapidly, therefore, and airspeed and rate of descent were controlled largely by power adjustment. Speed brakes (which also housed the drogue chute) were opened at any point on final turn or approach. Power was then incrementally reduced after the final roll out to reach prior-to-flared' speed, and then reduced to idle as aerodynamic braking killed airspeed until the main gear wheels touched The drag chute was deployed at touchdown and the nose was maintained at about 15 degrees to further scrub speed until the nose-gear dropped on its own to the runway as the aircraft slowed down.

Pilots reported that coming in hot across the end of the runway at 180 knots was a source of some major excitement in a high-performance delta-winged fighter such as the Six, and reliable word has it those landings in cold areas where icy runways were common during winter operations were even more thrilling. The margin for error was small in these circumstances, and flight proficiency was the key operative phrase for Six pilots. A normal interception mission was anywhere from 100 to 120 minutes in duration, depending upon the type and profile of mission flown.

Once off the active runway, the drag chute handle was pressed fully home, which action released it, and a taxi back to the ramp usually brought a gratifying feeling of great fulfillment to Sixers' in having once more flown a satisfying mission in this beautiful beast.


Despite the level of sophistication found in the F106A Delta Dart in its service life, it was regarded by the US Air Force as having the greatest mission-task loaded cockpit' among all active USAF service aircraft types flown in the 70s, 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 its heart and soul. 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.

Inevitably, though, as the years progressed, it was the MA-I weapons navigation and control system, comprising the core of the aircraft, which brought the career of this greatest of interceptor aircraft to an end By today's standards the marvel that was the Hughes Aircraft Company MA-I system of the late 50s, 60s, and 70s is now an obsolesced, archaic relic and it finally became too burdensome to attempt to maintain the MA-1 systems in repair....especially with the technologically advanced avionics systems being brought into use on the newer generation F15 and F16 aircraft of today.

When the last F106A & B model interceptors were retired from regular and ANG service between 1985 and 1988, they were flown to the USAF�'s AMARC depot and placed in storage. Most were converted to remotely flyable QF-106 (man-rated) target drones and sent to Tyndall and Holloman air force bases for use as target aircraft. Of the total of 340 A & 63 B models produced, about 230 were eventually converted to QF-106 target drone status by Tracor Flight Systems at Mojave Airport in California. When the last target drone flight was completed at Tyndall AFB in 1997, there were about two dozen un-flyable QF-106s left in the area at Tyndall known as The Swamp'. There were also about 7 flight-worthy Six survivors, all of which were flown back to AMARC for storage, joining about 35 other Sixes that had been designated as parts donors and kept at AMARC to support the Pacer Six' program. As stated earlier, about 7 of the non-flying Sixes left at Tyndall were sold (through DRMO) to David Talofa's GrecoAir in El Paso Texas, where they are being restored for museum display. Two of the QF-106 drones had been requisitioned for use in the Delta Dagger' reusable towed space flight vehicle project at Dryden, designated Project Eclipse' (59- 0130 and 59-0010). At the end of that program both were again flown back to AMARC. Interestingly, a significant number of the last flyable Six drones were former 5th FIS aircraft (including both 59-0130 and 59- 0010). Most of these few remaining examples of the "Ultimate Interceptor"' have now found their way to air museums, via charge through US Air Force Museum authority, and it pleases me to no end that one of my old Minot AFB 5thFIS birds (59-0010) is now on its way to join our Sacramento McClellan Aviation Museum Foundation (former McClellan AFB Air Museum) collection, as the crown jewel' of our Century Series aircraft sub-collection. [Please see the associated history of that amazingly lucky survivor of the Sexy Six' aircraft, described by some (myself included) appreciators as The Class of the Century Series'].

One other 5th FIS survivor that is a particular favorite is 59-0003 (known as Balls 3�, of course). Balls-3 was designated as a parts donor airframe many years ago and escaped the fate of being used as a flying target; it was fortunate enough to find its way to the PIMA Air & Space Museum in Tucson AZ (adjacent to AMARC), where is has rested peacefully and undisturbed for the last 15 years on loan as part of the PIMA collection. It has recently been officially handed over to PIMA once and for all, and has now undergone the required demil procedure that is today required for all ex-military aircraft on loan to museums. It always gives me great pleasure to visit PIMA and renew old times with Balls 3. Shortly, however, we will have one of Balls-3�'s stable-mates right here at our McClellan Air Park, when 59-0010 arrives in March of 2005.

There was an old saying not long ago, spoken in reference to the Convair F-106 Delta Dart: When you're out of Sixes, you're out of interceptors� Pure air defense interceptors may now be relegated to aerospace history, but for many of us who served in the US Air Force during the Cold War�' era, there will never be another aircraft quite like the ultimate progeny of Herr Doktor Professor Lippisch�'s forward looking delta winged aircraft designs!


  • Mancus, Peter, "Red Alert: The F106 and the Case for Manned Interceptors," Wings, June, 1981 (magazine article).
  • (Author unknown), "Flying the 'Six" Air Force Magazine, October 1973 (magazine article).
  • Tokunaga, Katsuhiko, "Dart Out," Koku Fan Magazine, (issue & date ?--magazine article).
  • "The History of the Air Force Flight Test Center," Chapter 15, July- December 1957, Vol 1. (official USAF history publication, Edwards Flight Test Center).
  • Gamble, Maj. Gen. Jack and Capt. Patrick K. "Convair's Deadly Delta," USAF-USN Jet Fighters, 1988 (magazine article).
  • (Editors), "FANG: We Fly with the Convair F106s of the Florida Air National Guard", Air Combat Magazine, (1985?-magazine article).
  • Peacock, Lindsay, 'Aircraft Illustrated', (magazine article, date & issue unknown).
  • Detail & Scale Publications: "F102A Delta Dagger" (illustrated book).
  • Detail & Scale Publications: "F106A Delta Dart" (illustrated book).
  • Dabrouski, Hans-Peter, "Lippisch P13A & Experimental DM-I," Schiffer Military History, Volume 67, Atglen, Pennsylvania, 1990 (illustrated book).
  • USAF Technical Order 1F-106A-23, [Downloadable Manuals here]