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Cold War interceptor of the US Air Force From Wikipedia, the free encyclopedia
The Convair F-102 Delta Dagger[N 2] is an interceptor aircraft designed and produced by the American aircraft manufacturer Convair. A member of the Century Series, the F-102 was the first operational supersonic interceptor and delta-wing fighter operated by the United States Air Force (USAF).
| F-102 Delta Dagger | |
|---|---|
| YF-102 prototype | |
| General information | |
| Type | Interceptor aircraft |
| Manufacturer | Convair |
| Primary users | United States Air Force |
| Number built | 1,000 |
| History | |
| Introduction date | April 1956 |
| First flight | 24 October 1953 |
| Retired | 1979[N 1] |
| Developed from | Convair XF-92 |
| Developed into | Convair F-106 Delta Dart |
The F-102 was designed in response to a requirement, known as the 1954 Ultimate Interceptor, produced by USAF officials during the late 1940s. Its main purpose was to be the backbone of American air defences and to intercept approaching Soviet strategic bomber fleets (primarily the Tupolev Tu-95) during the Cold War. The aircraft was designed alongside a sophisticated fire-control system (FCS); however, a simplified unit had to be adopted due to development difficulties. It used an internal weapons bay to carry both guided missiles and rockets. On 23 October 1953, the prototype YF-102 performed its maiden flight; however, it was destroyed in an accident only nine days later. The second prototype allowed flight testing to resume three months later, but results were disappointing: as originally designed, the aircraft could not achieve Mach 1 supersonic flight.
To improve its performance prior to quantity production commencing, the F-102 was redesigned, its fuselage was reshaped in accordance with the area rule while a thinner and wider wing was also adopted. Flight testing demonstrated sufficient performance improvements for the USAF to be persuaded to permit its production; a new production contract was signed during March 1954. Following its entry to USAF service in 1956, the F-102 promptly replaced various subsonic fighter types, such as the Northrop F-89 Scorpion, in the interceptor role. The F-102C tactical attack model, equipped with several improvements, including a more powerful engine and Gatling gun, was proposed but not ultimately pursued. A total of 1,000 F-102s were built, both for the USAF and a handful of export customers, including the Hellenic Air Force and the Turkish Air Force.
By the 1960s, USAF F-102s had participated in a limited capacity in the Vietnam War as a bomber escort and even in the ground-attack role. The aircraft was supplemented by McDonnell F-101 Voodoos and, later on, by McDonnell Douglas F-4 Phantom IIs. Over time, many F-102s were retrofitted with infrared search/tracking systems, radar warning receivers, transponders, backup artificial horizons, and modified fire-control systems. Throughout the mid-to-late 1960s, many USAF F-102s were transferred from the active duty Air Force to the Air National Guard, and, with the exception of those examples converted to unmanned QF-102 Full Scale Aerial Target (FSAT) drones, the type was totally retired from operational service in 1976. Its principal successor in the interceptor role was the Mach 2-capable Convair F-106 Delta Dart, which was an extensive redesign of the F-102.
On 8 October 1948, the board of senior officers of the United States Air Force (USAF) issued recommendations that the service organize a competition for a new interceptor scheduled to enter service in 1954; as such, the all-new design would initially be dubbed the "1954 Ultimate Interceptor".[2] Four months later, on 4 February 1949, the USAF approved the recommendation and prepared to hold a corresponding competition during the following year.[3] In November 1949, the USAF decided that the new aircraft would be built around a fire-control system (FCS). The FCS was to be designed before the airframe to ensure compatibility.[4][5] The airframe and FCS together were called the weapon system.
In January 1950, the USAF's Air Materiel Command issued request for proposals (RFPs) to 50 companies for the FCS, of which 18 responded. By May, the list was revised downward to 10. Meanwhile, a board at the U.S. Department of Defense headed by Major General Gordon P. Saville reviewed the proposals, and distributed some to the George E. Valley-led Air Defense Engineering Committee. Following recommendations by the committee to the Saville Board, the proposals were further reduced to two competitors, Hughes Aircraft and North American Aviation. Although the Valley Committee thought it was best to award the contract to both companies, Hughes was chosen by Saville and his team on 2 October 1950.[6][7]
In June 1950, the requirement for the airframe was formally issued; during January 1951, six aircraft manufacturers submitted nine responses.[7] On 2 July 1954, three of the responding companies, Convair, Republic, and Lockheed, were authorised to proceed with the building of a mockup. Upon completion, the three designs would be competitively reviewed, the best of which would lead to the awarding of a single production contract under the name Project MX-1554. Prior to this requirement, Convair had performed considerable early research into delta-winged aircraft and had experimented with various different designs, two of which fell under the name P-92.[8] For the era, Convair's submitted design was relatively unorthodox, not only in terms of the delta wing configuration but the decision to carry all munitions within an internal weapons bay to reduce drag; despite this, Republic's design was even more radical, proposing to use ramjet propulsion to attain speeds in excess of Mach 3.[7]
Ultimately, Convair's design emerged as the front runner for the requirement, which was officially designated XF-102. Lockheed had chosen to drop out to concentrate on other opportunities while Republic's design had been judged to involve too much technical risk to meet the 1954 deadline for service entry, thus was disqualified, making Convair the de facto winner.[6][9] The development of three different designs has been considered to be too expensive to proceed with, thus only Convair was permitted to do so in November 1951.[10] From an early stage, USAF officials had decided to use the Cook-Craigie Plan for the aircraft's manufacturing; under this concept, production tooling and facilities would be created while a small pre-production batch of aircraft would be completed, the aim being to eliminate the need for a lengthy prototype program, instead incorporating any changes required into the production line. However, if substantial modifications were necessary, re-tooling would then become necessary as well.[11] In December 1951, in order to accelerate the aircraft's development, it was proposed to equip the prototypes and pre-production aircraft with the less-powerful Westinghouse J40 turbojet.[12]
During early 1953, by which point construction of the first aircraft had reached an advanced stage, it had become clear that there were serious design challenges present, including wind tunnel testing that revealed early performance projections to have been overly optimistic.[13] Furthermore, there had been sustained delays to both the Curtiss-Wright J67 engine, a licensed derivative of the Bristol-Siddeley Olympus which was still in development,[14] and the MA-1 (formerly MX-1179) FCS;[15] to address the latter, decision makers opted to order an interim aircraft with the J40 and a simpler FCS (initially referred to as E-9) into production as the F-102A.[16] The failure of the J40 led to the Pratt & Whitney J57 turbojet with afterburner, rated with 10,000 pounds-force (44 kN) of thrust,[17] being substituted for the prototypes and F-102As.[18][19] This aircraft was intended to be temporary, pending the development of the more advanced F-102B, which would employ the more advanced J67. The F-102B would later evolve to become the F-106A, dubbed the "Ultimate Interceptor".[17][16]
On 23 October 1953, the YF-102 prototype conducted its first flight from Edwards Air Force Base, piloted by Convair's chief test pilot Richard L. Johnson.[20] Its flying career was very brief as it was lost in an accident only nine days later during a failed attempt to reach Mach 1. The accident, which was caused by severe buffeting, seriously injured Johnson.[21] The second aircraft flew on 11 January 1954, confirming a dismal performance. Transonic drag was much higher than expected, and the aircraft was limited to Mach 0.98 (i.e. subsonic), with a ceiling of 48,000 ft (14,630 m), far below the requirements.[22]
During mid 1953, Convair concluded that it needed to take action to address the F-102's shortcomings to prevent its cancellation, and promptly embarked on a major redesign effort.[20] It was decided to incorporate the recently discovered area rule, the application of which simultaneously simplified both production and maintenance of the aircraft.[23] This redesign entailed the lengthening of the fuselage by 11 ft (3.35 m), being "pinched" at the midsection (dubbed the "Coke Bottle configuration"), with two large fairings on either side of the engine nozzle, with revised intakes and a new, narrower canopy. A more powerful model of the J57 was installed while the aircraft structure was also lightened.[24][25]
In parallel to this effort, the wing was also redesigned to be both thinner and wider. The leading edge was reprofiled with a conical droop, with the apex at the root, as to improve handling at low speeds. Because the droop remained within the shock cone of the leading edge, the drag rise at supersonic speeds was minimal. A second, inboard fence was also added at the time.[26][27] A new canopy was also adopted while the tail was shifted slightly aft. The level of changes that could be implemented were restrained by the redesign having occurred at such an advanced stage of development.[28] Yet, the overall changes made were so substantial that two-thirds of the roughly 30,000 tools created to manufacture the YF-102 were scrapped or modified before quantity production had even commenced.[21]
On 20 December 1954, the first revised aircraft, designated YF-102A, made its first flight only 118 days after work on the redesign had started.[28] The next day, it exceeded Mach 1 for the first time.[25][29] The revised design quickly demonstrated that it could attain a speed of Mach 1.22 and a ceiling of 53,000 ft (16,154 m). These performance improvements were sufficient for the USAF to agree to procure the F-102; accordingly, a new production contract was signed during March 1954.[30] On 24 June 1955, the first flight of a production standard F-102 occurred.[31] From the 26th production aircraft onwards, a taller vertical tail with a 40 percent greater surface area was fitted to counteract flutter and a lack of directional control at high speeds; existing aircraft were also retrofitted with this change.[32]
The production F-102A had the Hughes MC-3 FCS, which was later upgraded in service to the MG-10; it was used to locate enemy targets, steer interception courses, and control weapons deployment.[33] The F-102 was the first USAF fighter to be designed without a gun, instead relying on missiles as its primary armament.[32] It had a three-segment internal weapons bay under the fuselage for air-to-air missiles. Initial armament was three pairs of GAR-1/2/3/4 (Later re-designated as AIM-4) Falcon missiles, which included both infrared homing and semi-active radar homing variants. The doors of the two forward bays each had tubes for 12 Folding-Fin Aerial Rockets (for a total of 24 "FFAR", with initially 2 in (51 mm) being fitted and later 2.75 in (70 mm) replacing them.[34] The F-102 was later upgraded to allow the carrying of up to two GAR-11/AIM-26 Nuclear Falcon missiles in the center bay.[35] The larger size of this weapon required redesigned center bay doors with no rocket tubes. Plans were considered to fit the MB-1 Genie nuclear rocket to the design, but although a Genie was test fired from a YF-102A in May 1956, it was never adopted.[36][37]
The F-102 received several major modifications during its operational lifetime, with most airframes being retrofitted with infra-red search and tracking systems, radar warning receivers, transponders, backup artificial horizons, and improvements to the fire control system.[38][39] A proposed close-support version (never built) would have incorporated an internal Gatling gun, and an extra two hardpoints for bombs, supplementing the two underwing pylons all production F-102s were fitted with for drop tanks (the use of which reduced the craft to subsonic performance[40]). To alleviate this, bigger internal fuel tanks and an in-flight-refueling probe were fitted.[38]
In response to a USAF request for a specialized twin-seat trainer, Convair begun development of the TF-102A in April 1952.[41] The side-by-side seating design, popularized in the 1950s (and used with the American Cessna T-37, British Hawker Hunter T.7 and English Electric Lightning T.4, among others), would require a redesign of the cockpit and a nose almost as wide as that of a Convair 340 commercial airliner. Development was put on hold despite being authorized on 16 April 1953 until issues with the fighter model were sufficiently addressed; the first firm order for the TF-102A was issued in July 1954, and a maiden flight made on 8 November 1955.[42] The new nose introduced buffeting, the source of which was traced to the bulbous canopy. Vortex generators were added to the top of the canopy to prevent the buffet which had started at about Mach 0.72.[43][44] The intake ducts were revised as the inlets were repositioned. Despite the many changes, the aircraft was combat-capable, although this variant was predictably slower, reaching only subsonic speeds in level flight.[45] A total of 111 TF-102As were eventually manufactured.[46]
The numerous inherent design and technical limitations of the F-102 led to a proposed successor, initially known as the F-102B "Ultimate Interceptor". The improved design, in which the proposed Curtiss-Wright J67 jet engine was eventually replaced by a Pratt & Whitney J75, underwent so many aerodynamic changes (including variable-geometry inlets) that it essentially became an entirely new aircraft and hence was redesignated and produced as the F-106 Delta Dart. Convair would also use a delta wing design in the Mach 2 class Convair B-58 Hustler bomber.
In June 1956, operational use of the F-102A commenced, the first unit to be equipped with the type being the 327th Fighter-Interceptor Squadron, which was initially based at George Air Force Base.[36][47] In June 1958, the 327th was redeployed to Thule Air Base on Greenland, the USAF's northernmost base, which permitted the interception of Soviet aircraft at a greater distance from the continental United States.[48] Other overseas units, such as the United States Air Forces in Europe (USAFE) and the 57th Fighter-Interceptor Squadron, based at Keflavik, Iceland, would similarly adopt the type and as such used the F-102 in the interceptor role through into the early 1970s until it was displaced by the arrival of newer fighter aircraft.[49] Typical interceptions included Soviet long range reconnaissance flights and bomber patrols over the Atlantic Ocean along with various aircraft that were flying to and from Cuba.[50]
The F-102's official name, "Delta Dagger", was never used in common parlance, with the aircraft being universally known as the "Deuce".[31] The TF-102 was known as the "Tub" because of its wider fuselage to accommodate its side-by-side twin seating arrangement.[51]
During the decades in which the F-102A was in service, several new wing designs were used to experiment with the application of increased conical camber to the wings. Ultimately, a design was selected that actually increased elevon area, reduced takeoff speed, improved the supersonic L/D ratio and increased the aircraft's ceiling to 56,000 ft (17,069 m). A modification was required to the landing gear doors due to the wing redesign.
By 1960, the Air Defense Command (ADC) had F-102 Delta Daggers in service. Throughout the 1960s, a considerable number of the ADC's TF-102s and F-102s were stationed at Perrin AFB, Texas, for the purpose of training new F-102 pilots. They also provided platform training on flight characteristics of delta-winged aircraft for pilots who were destined to fly the B-58 Hustler bomber for the Strategic Air Command (SAC).
The type continued to serve in large numbers with both Air Force and Air National Guard units well into the 1970s. George W. Bush, later President of the United States, flew the F-102 in the 147th Fighter Interceptor Group based at Ellington AFB in Houston, Texas as part of his Texas Air National Guard service from 1968 to 1972.[52]
The F-102 served in the Vietnam War, flying fighter patrols and serving as bomber escorts. A total of 14 aircraft were lost in Vietnam: one to air-to-air combat,[53] several to ground fire and the remainder to accidents.
Initially, F-102 detachments began to be sent to bases in Southeast Asia in 1962 after radar contacts detected by ground radars were thought to possibly be North Vietnamese Vietnam People's Air Force (VPAF) Il-28 "Beagle" bombers – considered to be a credible threat in that time period. The F-102s were sent to Thailand and other nearby countries to intercept these aircraft if they threatened South Vietnam.[54]
Later on, Boeing B-52 Stratofortress strikes, codenamed "Arc Light", were escorted by F-102s based in the theater. It was during one of these missions that an F-102 was shot down by a VPAF Mikoyan-Gurevich MiG-21 using an AA-2 Atoll heat-seeking missile. The MiGs approached undetected, and one of the F-102s was hit by an air-to-air missile, which did not explode immediately, but remained lodged in the aft end of the aircraft, causing stability problems. As the pilot reported the problem to his wingman, the wingman observed the damaged Delta Dagger explode in midair, killing the pilot.[55] This was the only air-to-air loss for the F-102 during the Vietnam War. The other F-102 pilot fired AIM-4 missiles at the departing MiG-21s, but no hit was recorded.
The F-102 was occasionally employed in the air-to-ground role with limited success, although neither the aircraft nor the training for its pilots were designed for that role. The 509th Fighter-Interceptor Squadron's (FIS) Deuces arrived at Da Nang Air Base from Clark Air Base, Philippines, on 4 August 1964.[56] The interceptor was equipped with 24 2.75 in (70 mm) FFARs in the fuselage bay doors; these could be used to good effect against various types of North Vietnamese targets in daylight. At night, it proved less dangerous to use heat-seeking Falcon missiles in conjunction with the F-102's nose-mounted IRST (Infrared Search & Track), thus it often performed nighttime harassment raids along the Ho Chi Minh Trail.[57] Some F-102As were configured to accommodate a single AIM-26 Super Falcon in each side bay in lieu of the two conventional AIM-4 Falcons. Operations with both the F-102A and TF-102A two-seaters (which were used in a Forward Air Control role because its two seats and 2.75 in/70 mm rockets offered good versatility for the mission) continued in Vietnam until 1968 when all F-102s were returned to the United States.
| Date | F-102 model | Unit | Cause of loss/remarks |
|---|---|---|---|
| 27 November 1964 | F-102A | 509th FIS | Engine failure.[58] |
| 1 July 1965 | F-102A | 509th FIS | (3) F-102As destroyed on the ground by enemy sappers at Da Nang Air Base.[59] |
| 15 December 1965 | F-102A | 509th FIS | Downed by ground fire while providing close air support (CAS).[60] |
| 19 August 1966 | F-102A | 509th FIS | Operational loss, crashed during night landing.[61] |
| 14 December 1966 | F-102A | 64th FIS | Downed by small arms fire within 60 seconds after takeoff.[62] |
| 15 January 1967 | TF-102A | 509th FIS | Operational loss, ferry mission.[63] |
| 2 April 1967 | F-102A | 509th FIS | Operational loss, engine failure. Also served with 16th & 64th FIS.[64] |
| 12 May 1967 | F-102A | 509th FIS | Destroyed during enemy ground attack; mortar fire at Biên Hòa Air Base.[65] |
| 3 February 1968 | F-102A | 509th FIS | Downed by MiG-21 K-13 (missile) at 36,000 feet (11,000 m).[66] |
| 16 July 1968 | F-102A | 509th FIS | Operational loss, engine failure.[67] |
| 16 September 1968 | F-102A | 509th FIS | Operational loss, ground collision after landing with an RF-4 Phantom II.[68] |
| 7 January 1969 | F-102A | 509th FIS | Operational loss, engine failure.[69] |
During 1973, six aircraft were converted to target drones as QF-102As and later PQM-102Bs (simulating MiG-21 threat aircraft) under a Full Scale Aerial Target (FSAT) project known as Pave Deuce.[70][71] Eventually, the program converted hundreds of F-102s for use as target drones for newer fighter aircraft, as well as testing of the U.S. Army's Patriot missile system.[72]
The F-102 and TF-102 were exported overseas to both Turkey and Greece. The Turkish F-102s saw combat missions during the 1974 Turkish invasion of Cyprus. There have been claims of air combat between Greek F-5s and Turkish F-102s above the Aegean Sea during the Turkish invasion. A Greek internet website editor, Demetrius Stergiou, claims that the Greek F-5s had shot down two Turkish F-102s, while the Turkish side has claimed that their F-102s had shot down two Greek F-5s;[73] however, both Greece and Turkey still officially deny any aircraft losses. The F-102 was finally retired from both of those air forces in 1979.
In 1976, the F-102 was withdrawn from U.S. service, while the last QF-102A / PQM-102B drone was expended in 1986. As of 2023, no F-102s remain in flyable condition, although many can be seen at museums or as permanent static displays as gate guardians at Air Force and Air National Guard installations.
In 1969, Greece acquired 24 of these aircraft for use by the 342nd All-Weather Squadron at Tanagra Air Base. 19 of them were single-seat F-102As, five were two-seat TF-102As. They served with the Greek air force until 1977, when the F-102s were replaced by Mirage F1CG fighters.[77]
Beginning in 1968, approximately 50 F-102As and TF-102As were transferred to Turkey from USAF stocks. Before transfer to Turkey, they were overhauled by CASA in Seville. They were initially assigned to the 191st Filo (Squadron) based at Murted, replacing the F-84F Thunderstreaks previously assigned to this unit. This unit was redesignated 142nd Filo in early 1973. In 1971, F-102s were also assigned to the 182nd Filo based at Diyarbakır, replacing the F-84Fs previously being flown by this unit. F-102s remained in service with these two squadrons until mid-1979, when they were replaced by the F-104G in the 142nd Filo and by the F-100C in the 182nd Filo.[citation needed]
United StatesNational Aeronautics and Space Administration
Data from The Great Book of Fighters[112]
General characteristics
Performance
Armament
Avionics
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Aircraft of comparable role, configuration, and era
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