The F-102 was designed in response to a requirement, known as the1954 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 approachingSovietstrategic bomber fleets (primarily theTupolev Tu-95) during theCold War. The aircraft was designed alongside a sophisticatedfire-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 itsmaiden 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 achieveMach 1supersonic flight.
To improve its performance prior to quantity production commencing, the F-102 was redesigned, its fuselage was reshaped in accordance with thearea 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 varioussubsonic fighter types, such as theNorthrop F-89 Scorpion, in the interceptor role. TheF-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 theHellenic Air Force and theTurkish Air Force.
By the 1960s, USAF F-102s had participated in a limited capacity in theVietnam War as abomber escort and even in theground-attack role. The aircraft was supplemented byMcDonnell F-101 Voodoos and, later on, byMcDonnell Douglas F-4 Phantom IIs. Over time, many F-102s were retrofitted withinfrared search/tracking systems,radar warning receivers, transponders, backupartificial 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 theAir National Guard, and, with the exception of those examples converted to unmannedQF-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-capableConvair F-106 Delta Dart, which was an extensive redesign of the F-102.
On 8 October 1948, the board of senior officers of theUnited 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 afire-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'sAir Materiel Command issuedrequest 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 byMajor GeneralGordon P. Saville reviewed the proposals, and distributed some to theGeorge 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 andNorth 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, andLockheed, 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 nameProject 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 nameP-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 reducedrag; despite this, Republic's design was even more radical, proposing to useramjet 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 designatedXF-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-powerfulWestinghouse J40turbojet.[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, includingwind tunnel testing that revealed early performance projections to have been overly optimistic.[13] Furthermore, there had been sustained delays to both theCurtiss-Wright J67 engine, a licensed derivative of theBristol-Siddeley Olympus which was still in development,[14] and the MA-1 (formerlyMX-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 asE-9) into production as theF-102A.[16] The failure of the J40 led to thePratt & 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, theYF-102 prototype conducted its first flight fromEdwards 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.Transonicdrag was much higher than expected, and the aircraft was limited to Mach 0.98 (i.e. subsonic), with a ceiling of 48,000 ft (15,000 m), far below the requirements.[22]
YF-102A with pinched "area rule" fuselage, narrower canopy and redesigned intakes
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 discoveredarea 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 (3.4 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. Theleading 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, designatedYF-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 (16,000 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 forair-to-air missiles. Initial armament was three pairs ofGAR-1/2/3/4 (Later re-designated as AIM-4) Falcon missiles, which included bothinfrared homing andsemi-active radar homing variants. The doors of the two forward bays each had tubes for 12Folding-Fin Aerial Rockets for a total of 24 "FFAR", with initially 2-inch (51 mm) rockets being fitted and later 2.75-inch (70 mm) replacing them.[34] The F-102 was later upgraded to allow the carrying of up to twoGAR-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 theMB-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]
Hughes MC-3 fire control system and radar antenna
The F-102 received several major modifications during its operational lifetime, with most airframes being retrofitted withinfra-red search and tracking systems,radar warning receivers, transponders, backupartificial horizons, and improvements to thefire control system.[38][39] A proposed close-support version (never built) would have incorporated an internalGatling gun, and an extra twohardpoints for bombs, supplementing the two underwing pylons all production F-102s were fitted with fordrop tanks (the use of which reduced the craft to subsonic performance[40]). To alleviate this, bigger internal fuel tanks and anin-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 AmericanCessna T-37, BritishHawker Hunter T.7 andEnglish 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 aPratt & 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 classConvair B-58 Hustler bomber.
In June 1956, operational use of the F-102A commenced, the first unit to be equipped with the type being the327th Fighter-Interceptor Squadron, which was initially based atGeorge Air Force Base.[36][47] In June 1958, the 327th was redeployed toThule Air Base onGreenland, 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 theUnited States Air Forces in Europe (USAFE) and the57th Fighter-Interceptor Squadron, based atKeflavik,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 theAtlantic Ocean along with various aircraft that were flying to and fromCuba.[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 (17,000 m). A modification was required to the landing gear doors due to the wing redesign.
By 1960, theAir 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 atPerrin 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 theStrategic Air Command (SAC).
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 VietnameseVietnam 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]
F-102As of the 509th FIS over Vietnam, November 1966. These aircraft wear standard Southeast Asia camouflage (T.O. 1-1-4).
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 VPAFMikoyan-Gurevich MiG-21 using anAA-2 Atollheat-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. The509th Fighter-Interceptor Squadron's (FIS) Deuces arrived atDa Nang Air Base fromClark Air Base, Philippines, on 4 August 1964.[56] The interceptor was equipped with 24 2.75-inch (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 theHo 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.
Summary of (14) USAF F-102 Delta Daggers lost in the Vietnam War 1964–1969
During 1973, six aircraft were converted totarget drones as QF-102As and later PQM-102Bs (simulating MiG-21 threat aircraft) under a Full Scale Aerial Target (FSAT) project known asPave 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'sPatriot 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 1974Turkish invasion of Cyprus. There have been claims of air combat between GreekF-5s and Turkish F-102s above theAegean 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 asgate guardians at Air Force and Air National Guard installations.
In 1969, Greece acquired 24 of these aircraft for use by the342nd All-Weather Squadron atTanagra 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 byMirage 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]
56-1252 –Ellington Field Joint Reserve Base,Houston, Texas. Future President of the United States George W. Bush flew this model with the 147th Fighter Interceptor Group, 111th Fighter Interceptor Squadron of the Texas Air National Guard in the early 1970s. It is mounted on a pole that exits the burner. His name is on the canopy.[citation needed]
^Aircraft Recognition Manual, Supplement No. 5 (Army Field Manual), Volume FM 30-30, June 1954, p. 11. Washington, D.C.: United States Department of Defense.
^Baugher, Joseph F."Convair F-102A Delta Dagger".JoeBaugher.com. Joseph F. Baugher.Archived from the original on 5 November 2010. Retrieved8 February 2022.
^"F-102 Drones".www.joebaugher.com.Archived from the original on 25 September 2017. Retrieved28 April 2018.
^Stergiou, Demetrius."The Shooting Down of the Turkish F-102s" (translation and verbatim by Nicholas Tselepidis).Cyprus 1974: Greek Point of View viaacig.org, 28 October 2003. Retrieved: 27 October 2010.
^Baugher, Joe."Convair F-102C."Archived 24 November 2010 at theWayback MachineUSAAC/USAAF/USAF Fighter and Pursuit Aircraft: Original Fighter Series-1922 to 1962, 4 December 1999. Retrieved: 25 March 2011.
^Baugher, Joe."Squadron Service of F-102A"Archived 24 November 2010 at theWayback MachineUSAAC/USAAF/USAF Fighter and Pursuit Aircraft: Original Fighter Series-1922 to 1962, 14 February 2004. Retrieved: 9 October 2011.
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