Lockheed F-104 Starfighter

The XF-104 Starfighter prototype

Clarence L. "Kelly" Johnson, vice president of engineering and research at Lockheed's Skunk Works, visited USAF air bases across South Korea in November 1951 to speak with fighter pilots about what they wanted and needed in a fighter aircraft.[6][7] At the time, the American pilots were confronting the MiG-15 with North American F-86 Sabres, and many felt that the MiGs were superior to the larger and more complex American design. The pilots requested a small and simple aircraft with excellent performance, especially high speed and altitude capabilities.[8] Armed with this information, Johnson immediately started the design of such an aircraft on his return to the United States. In March 1952, his team was assembled; they studied over 100 aircraft designs,[9] ranging from small designs at just 8,000 lb (3,600 kg),[10] to large ones up to 50,000 lb (23,000 kg).[11] In order to achieve the desired performance, Lockheed chose a small and simple aircraft, weighing in at 12,000 lb (5,400 kg) with a single powerful engine. The engine chosen was the new General Electric J79 turbojet, an engine of dramatically improved performance in comparison with contemporary designs.[12] The small L-246 design powered by a single J79 remained essentially identical to the Model 083 Starfighter as eventually delivered.[13]

Johnson presented the design to the Air Force on 5 November 1952, and they were interested enough to create a general operational requirement for a lightweight fighter to supplement and ultimately replace the yet-to-fly North American F-100. Three additional companies were named finalists for the requirement: Republic Aviation with the AP-55, an improved version of its prototype XF-91 Thunderceptor; North American Aviation with the NA-212, which eventually evolved into the F-107; and Northrop Corporation with the N-102 Fang, another J79-powered design. Although all three finalists' proposals were strong, Lockheed had what proved to be an insurmountable head start, and was granted a development contract on 12 March 1953 for two prototypes; these were given the designation "XF-104".[14][15]

Work progressed quickly, with a mock-up ready for inspection at the end of April,[14] and work starting on two prototypes that summer.[16] Meanwhile, the J79 engine was not ready; both prototypes were instead designed to use the Wright J65 engine, a licensed-built version of the Armstrong Siddeley Sapphire.[17] The first prototype was completed by early 1954 and first flew on 4 March at Edwards AFB.[1] The total time from contract to first flight was less than one year.[18]

Though development of the F-104 was never a secret, only a vague description of the aircraft was given when the USAF first revealed its existence. No photos of the airplane were released to the public until 1956, even though the XF-104 first flew in 1954. At the April 1956 public unveiling of the YF-104A, the engine inlets were obscured with metal covers and visible weapons, including the M61 Vulcan cannon, were also hidden.[19][20] Despite the secrecy, an artist's rendering of the yet-unseen F-104 appeared in the September 1954 edition of Popular Mechanics that was very close to the actual design.[21]

The prototype made a hop into the air during taxi trials on 28 February 1954 and flew about five feet (1.5 m) off the ground for a short distance, but was not counted as a first flight. On 4 March, Lockheed test pilot Tony LeVier flew the XF-104 for its first official flight; he was airborne for only 21 minutes, much shorter than planned, due to landing gear retraction problems.[22][23] The second prototype was destroyed several weeks later during gun-firing trials,[24] but on 1 November 1955 the XF-104 was accepted by the USAF.[25]

Based on the XF-104 testing and evaluations, the next variant, the YF-104A, was lengthened and fitted with a General Electric J79 engine, modified landing gear, and modified air intakes.[26] The YF-104A and subsequent models were 5 feet 6 inches (1.68 m) longer than the XF-104 to accommodate the larger GE J79 engine. The YF-104 initially flew with the GE XJ79-GE-3 turbojet with 9,300 pounds of dry thrust (14,800 with afterburner), which was later replaced by the J79-GE-3A with an improved afterburner.[27]

The first YF-104A flew on 17 February 1956 and, with the other 16 trial aircraft, were soon carrying out aircraft and equipment evaluation and tests. Lockheed made several improvements to the aircraft throughout the YF-10A testing period, including strengthening the airframe, adding a ventral fin to improve directional stability at supersonic speed, and installing a boundary layer control system (BLCS) to reduce landing speed.[27]

Problems were encountered with the J79 afterburner; further delays were caused by the need to add AIM-9 Sidewinder air-to-air missiles. On 28 January 1958, the first production F-104A to enter service was delivered to the 83rd Fighter Interceptor Wing.[28]

A total of 2,578 F-104s were produced by Lockheed and under license by various foreign manufacturers.[29]

The Starfighter's airframe was all-metal, primarily duralumin with some stainless steel and titanium. The fuselage was approximately two and a half times longer than the airplane's wingspan. The wings themselves were centered on the horizontal reference plane, and were located substantially farther back on the fuselage than most contemporary designs. The aft fuselage was somewhat elevated from the horizontal reference plane, and the nose was "drooped"; this caused the aircraft to assume a slight "nose-up" attitude, which allowed the plane to fly at the minimum-drag angle of attack. As a result, the pitot tube, air inlet scoops, and engine thrust line were all canted slightly with respect to the longitudinal centerline of the fuselage.[30][31]

The F-104 featured a radical wing design. Most jet fighters of the period used a swept-wing or delta-wing, which provided a reasonable balance between aerodynamic performance, lift, and internal space for fuel and equipment. The Lockheed tests, however, determined that the most efficient shape for high-speed supersonic flight was a very small, straight, mid-mounted, trapezoidal wing. Much of the data on the wing shape was derived from testing done with the experimental unmanned Lockheed X-7, which used a similar-shaped wing.[32] The leading edge of the wing was swept back at 26 degrees, with the trailing edge swept forward by a slightly smaller amount.[31]

Lockheed F-104A

The new wing design was extremely thin, with a thickness-to-chord ratio of only 3.36% and an aspect ratio of 2.45.[33] The wing's leading edges were so thin (.016 in, 0.41 mm)[33] that they presented a cut hazard to ground crews: protective guards had to be installed on the edges during ground operations maintenance.[34] The thinness of the wings required fuel tanks and landing gear to be placed in the fuselage, and the hydraulic cylinders driving the ailerons were limited to 1-inch (25 mm) thickness in order to fit.[35]

The small, highly loaded wing resulted in an unacceptably high landing speed, even after adding both leading- and trailing-edge flaps. As a result, the aircraft designers developed a boundary layer control system, or BLCS, of high-pressure bleed air, which was blown over the trailing-edge flaps to lower landing speeds by more than 30 knots (56 km/h; 35 mph) and help make landing the airplane safer.[36][37] Flapless landings, however, would unfortunately be without the BLCS engaged, as flaps in the "land" position were required for its operation. Landing without the BLCS engaged was only done in emergencies and could be a harrowing experience, especially at night.[38]

The stabilator (fully moving horizontal stabilizer) was mounted high atop the fin to reduce inertia coupling. Because the vertical fin was only slightly shorter than the length of each wing and nearly as aerodynamically effective, it could act as a wing-on-rudder application, rolling the aircraft in the opposite direction of rudder input. To offset this effect, the wings were canted downward at a 10° negative-dihedral (anhedral) angle.[39] This downward canting also had the effect of improving roll control during high-g maneuvers during air-to-air combat.[33]

The fuselage had a high fineness ratio, i.e. slender, tapered towards the sharp nose, and a small frontal area. The tightly packed fuselage contained the radar, cockpit, cannon, fuel, landing gear, and engine. The fuselage and wing combination provided low drag except at high angle of attack (alpha), at which point induced drag became very high. The F-104 had good acceleration, rate of climb, and potential top speed, but its sustained turn performance was poor. A "clean" (no external weapons or fuel tanks) F-104 could sustain a 7-g turn below 5,000 feet with full afterburner, but given the aircraft's prodigious fuel consumption at that altitude and relatively small fuel capacity, such a maneuver would dramatically reduce its time on station.[40]

Detail of F-104G's J79 turbojet exhaust (the red coloring has been added by the museum)

The F-104 was designed to use the General Electric J79 turbojet engine,[41] fed by side-mounted intakes with fixed inlet cones optimized for performance at Mach 1.7 (increased to Mach 2 for later F-104s equipped with more powerful J79-GE-19 engines).[42] Unlike some supersonic aircraft, the F-104 did not have variable-geometry inlets; instead at high Mach numbers excess air was bypassed around the engine. This bypass air also helped cool the engine. Its thrust-to-drag ratio was excellent, allowing a maximum speed well in excess of Mach 2. Available thrust was actually limited by the geometry of the inlet scoop and duct; the aircraft was capable even higher Mach numbers except for the aerodynamic heating limitations of the aluminum structure.[43]

The engine consisted of a 17-stage compressor, accessory drive section, annular combustion chamber, three-stage turbine, and afterburner. The most powerful version of the J79, the J79-GE-19, was rated at 52.8 kN (11,900 lb_f) dry thrust and 79.6 kN (17,900 lb_f) with afterburner. Bleed air from the compressor's 17th stage was used for a number of purposes: the BLCS, cabin pressurization and air conditioning, hot-air jet rain removal, fuel transfer, canopy and windshield defogging and defrosting, pressure for the pilot's anti-G suit, pressurization and cooling of the nose-mounted radar equipment, and purging of gas from the M61 autocannon. The accessory drive ran two hydraulic pumps, two variable-frequency generators, the generator for the tachometer, and pumps for engine fuel and oil.[44][45]

The basic armament of the F-104 was the 20 mm (0.79 in) M61 Vulcan autocannon. As the first aircraft to carry the weapon, testing of the Starfighter revealed issues with the initial version of the M61: the Gatling-mechanism cannon suffered problems with its linked ammunition, being prone to misfeed and presenting a foreign object damage (FOD) hazard with discarded links. A linkless ammunition feed system was developed for the upgraded M61A1 installed in the F-104C; the M61A1 has subsequently been used by a wide variety of American combat aircraft.[46]

M61 cannon installation of a German Navy F-104G

The cannon, mounted in the lower part of the port fuselage, was fed by a 725-round drum behind the pilot's seat. With its firing rate of 6,000 rounds per minute, the cannon would empty the drum after just over seven seconds of continuous fire.[47] The cannon was omitted in all the two-seat models and some single-seat versions including reconnaissance aircraft, with the gun bay and ammunition drum typically replaced by additional fuel tanks.[48]

Two AIM-9 Sidewinder air-to-air missiles could be carried on the wingtip stations, which could also be used for fuel tanks. The F-104C and later models added a centerline pylon and two underwing pylons for bombs, rocket pods, or fuel tanks; the centerline pylon could carry a nuclear weapon.[47] A "catamaran" launcher for two additional Sidewinders could be fitted under the forward fuselage, although the installation had minimal ground clearance and rendered the seeker heads of the missiles vulnerable to ground debris. The F-104S models added a pair of fuselage pylons beneath the intakes available for conventional bomb carriage and an additional pylon under each wing, for a total of nine.[49]

Early Starfighters were also capable of carrying and launching a single MB-1 (AIR-2A Genie) rocket-powered nuclear missile using an extending trapeze launcher. This configuration was tested on a single aircraft but was not adopted for service use; however, NASA later used it for launching test rockets.[50]

NASARR radar on F-104

The initial USAF Starfighters had a basic RCA AN/ASG-14T1 ranging radar, tactical air navigation system (TACAN), and an AN/ARC-34 UHF radio. The AN/ASG-14 fire control system used a 24-inch (610 mm) pencil-beam radar antenna with two independent sights, one optical one infrared. Early versions of the radar had a range of approximately 20 miles (32 km) in search mode, with later models reaching up to 40 miles (64 km); the scan pattern was spiral, covering a 90-degree cone. Search mode was usable only above 3,000 feet (910 m) due to ground return effects below that altitude. Track mode was usable within 10 miles (16 km) of the target, which narrowed the scan to 20 degrees and initiated a strobe sweep between 300 and 3,000 yards (270 and 2,740 m) in auto-acquisition mode. The radar also had a third, receive-only mode useful for locking onto source of interference from electronic countermeasures (ECM).[51]

In the late 1960s, Lockheed developed a more advanced version of the Starfighter, the F-104S, for use by the Italian Air Force. Similar to the F-104G, Lockheed produced two main variants of the F-104S, a, all-weather interceptor (CI) and a strike aircraft (CB). The CI variant received a FIAR/NASARR F15G radar with AIM-7 Sparrow guidance capability; however, the new missile-guidance avionics came at the expense of the M61A1 Vulcan cannon, which was removed to make room. The CB variant was equipped with a FIAR/NASARR R21G-H radar and a radar altimeter for low-level strike missions, retaining the cannon as its only air-to-air weapon.[52]

As part of the Aggiornamento Sistema d'Arma (ASA), or "Weapons System Upgrade" in the mid-1980s, both variants were given an ALQ-70/72 ECM and a FIAR/NASARR R-21G/M1 radar with frequency hopping and look-down/shoot-down capability. The new radar and guidance systems enabled the aircraft to carry both the new AIM-9L Sidewinder infrared-guided missile (replacing the older AIM-9B) as well as the AIM-7 Sparrow and the Selenia Aspide radar-guided missiles.[53]

A Martin-Baker Mk.7 Ejection seat from an F-104G

Early Starfighters used a downward-firing ejection seat (the Stanley C-1), out of concern over the ability of an upward-firing seat to clear the "T-tail" empennage. This presented obvious problems in low-altitude escapes, and 21 USAF pilots, including test pilot Captain Iven Carl Kincheloe Jr., failed to escape from their stricken aircraft in low-level emergencies because of it. The downward-firing seat was replaced by the Lockheed C-2 upward-firing seat, which was capable of clearing the tail, but still had a minimum speed limitation of 90 kn (104 mph; 167 km/h).[54] Many export Starfighters were later retrofitted with Martin-Baker Mk.7 "zero-zero" (zero altitude and zero airspeed) ejection seats.[55]

The Starfighter was designed for production rates of up to 20 airplanes per day from a single assembly line. The entire aircraft was designed for modular assembly and disassembly: the two principal fuselage sections were split along the vertical centerline and completely assembled in two separate halves; all equipment, including wiring and plumbing, were installed inside the two-halves before being joined together. The wings were then attached with only ten bolts plus a fairing.[56]

F-104 test-firing an AIM-9 Sidewinder against a QF-80 target drone.

Although the F-104 was designed as an air-superiority fighter, the United States Air Force's immediate need at the time was for a supersonic interceptor. In the late 1950s, the United States government believed it was significantly behind the USSR in terms of the size of its jet-powered bomber fleet. In response, the USAF had ordered two interceptors from Convair, the F-102 Delta Dagger and the F-106 Delta Dart, but both aircraft were experiencing long development delays. The Starfighter's speed and rate-of-climb performance intrigued the Air Force, who pressed the F-104A into service as an interim interceptor with the Air Defense Command (ADC), even though its range and armament were not well-suited for the role. On 26 February 1958, the first unit to become operational with the F-104A was the 83rd Fighter Interceptor Squadron at Hamilton AFB, California.[50]

The newly operational aircraft experienced problems with both the J79 engine and M61 cannon, and after just three months of service, the unit was grounded after a series of engine-related accidents. The aircraft were then fitted with the J79-GE-3B engine and another three ADC units equipped with the F-104A. During this time, the Air Force's interest in the Starfighter was waning due to a shift in strategy toward fighters with longer range and heavier ordnance loads.[57] As a result, the USAF reduced their orders of the F-104A from 722 to 170,[58] and the F-104A and F-104B aircraft of the 83rd, 56th, and 337th Fighter Interceptor Squadrons (FIS) were handed over to the 151st, 157th, and 197th Squadrons of the Air National Guard after less than a year of service with ADC.[59]

A F-104A being loaded onto a C-124 at Hamilton AFB for transport to Formosa, 1958

In August 1958, only a few months after establishing operational readiness with the F-104, the 83rd FIS was assigned to a peacekeeping mission in Taiwan after the People's Republic of China began an intense artillery campaign against the Nationalist Chinese on the disputed islands of Quemoy and Matsu. Tensions between the two forces were already high; artillery duels were ongoing since the first crisis in 1954, and the PLAAF had recently relocated 200 MiG-15s and MiG-17s to airfields on the mainland opposite Taiwan. The Starfighters' presence, according to Col. Howard "Scrappy" Johnson, was so the PLAAF would "track them on their radar screens...and sit back and scratch their head in awe."[60]

83d FIS F-104As at Taoyuan Air Base, Taiwan, during the 1958 Quemoy Crisis

On 10 September, the first F-104s arrived in Formosa, delivered disassembled by C-124 Globemaster II transport aircraft. This was the first time that air transport was used to move fighter aircraft long distances. Within 30 hours of arriving, 1Lt Crosley J. Fitton had the first of the 83rd's airplanes in the air, and by 19 September the entire unit was ready for day or night alert status. The F-104 flew a number of supersonic runs between Taiwan and mainland China at speeds up to Mach 2 as an air-superiority demonstration, and though there were no direct enemy engagements prior to withdrawal after the 6 October ceasefire, the Starfighter provided a significant deterrent effect. USAF Gen Laurence Cuter, commander-in-chief of the Pacific Air Forces, reported that the F-104A had "made a tremendous impression on both sides of the Taiwan Strait".[61]

A USAF F-104A of the 151st FIS at Ramstein Air Base, West Germany, in 1961-1962.

During the Berlin Crisis of 1961, President John F. Kennedy ordered 148,000 United States National Guard and reserve personnel to active duty on 30 August 1961, in response to Soviet moves to cut off Allied access to Berlin. 21,067 individuals were from the Air National Guard (ANG), forming 18 fighter squadrons, four reconnaissance squadrons, six transport squadrons, and a tactical control group. On 1 November 1961, the USAF mobilized three more ANG fighter interceptor squadrons. In late October and early November, eight of the tactical fighter units flew to Europe with their 216 aircraft in "Operation Stair Step". Because of their short range, 60 F-104As were airlifted to Europe in late November, among them the 151st FIS and 157th FIS. As with the Taiwan crisis three years earlier, the Starfighter did not directly engage any enemy fighters, but its presence provided a powerful air-superiority deterrent; it demonstrated very quick reaction times and exemplary acceleration during practice intercepts, and proved superior to all other available fighters in the theater. The crisis ended in the summer of 1962 and the ANG personnel returned to the United States, but the F-104's solid performance helped convince the ADC to recall some F-104s back into active USAF service the following year.[62][63]

The subsequent F-104C entered service with USAF Tactical Air Command (TAC) as a multi-role fighter and fighter-bomber. The 479th Tactical Fighter Wing at George AFB, California, was the first unit to equip with the type in September 1958.[64] Although not an optimum platform for the theater, the F-104 did see limited service in the Vietnam War.[65] In 1967, these TAC aircraft were transferred to the Air National Guard.[66]

479th TFW F-104Cs at Da Nang, 1965

Starfighter squadrons made two deployments to Vietnam. Commencing with Operation Rolling Thunder, the Starfighter was used both in the air-superiority role and in the air-support mission. On 19 April 1965 the 476th Tactical Fighter Squadron (TFS) of the 479th Tactical Fighter Wing (TFW) arrived at Da Nang AB to help protect the F-105 Thunderchiefs against MiG-17s and especially MiG-21s that were beginning to be flown by the Vietnamese Peoples' Air Force (VPAF). The F-104 was also deployed extensively as a barrier combat air patrol (BARCAP) protector for the EC-121D Warning Star airborne early warning aircraft patrolling off the North Vietnamese coast.[67] The F-104s were successful in deterring MiG interceptors and performed well as close support aircraft, though they were largely uninvolved in aerial combat and recorded no air-to-air kills during the conflict.[68][69] The North Vietnamese were well aware of the F-104's performance, and the 479th TFW's pilots felt that the MiGs deliberately avoided engaging them. Twenty-five MiG kills were scored by fighters controlled by EC-121 Big Eye missions, and their Starfighter escorts played a vital role in ensuring their safety.[70]

During the first F-104 deployment from April to December 1965, Starfighters flew a total of 2,937 combat sorties. These sorties resulted in the loss of five aircraft, one from the 476th TFS deployed from April to July 1965,[71] and four from the 436th Tactical Fighter Squadron deployed from July to October 1965.[72][73] Two Starfighters were shot down by ground fire, one was shot down by a Shenyang J-6 when Capt. Philip E. Smith strayed into Chinese airspace, and two were lost to a mid-air collision while searching for Smith's missing jet.[74][75][76] No losses were reported from the 435th Tactical Fighter Squadron's first deployment from October to December 1965.[72]

Starfighters returned to Vietnam when the 435th Tactical Fighter Squadron re-deployed from June 1966 until August 1967.[72] During this time F-104s flew a further 2,269 combat sorties, for a total of 5,206.[77] F-104s operating in Vietnam were upgraded in service with AN/APR-25/26 radar warning receiver equipment,[78] with one example on display in the Air Zoo in Kalamazoo, Michigan.[79] During the second deployment, an additional nine aircraft were lost for a total of 14 F-104s lost to all causes in Vietnam. In July 1967, the Starfighter units transitioned to the McDonnell Douglas F-4 Phantom II.[72][80]

A German TF-104G at Luke AFB, 1982

The U.S. Air Force was less than satisfied with the Starfighter, and procured only 296 examples in single-seat and two-seat versions. At the time, USAF doctrine placed little importance on air superiority (fighter-to-fighter), and the Starfighter was deemed inadequate for either the interceptor (fighter-to-bomber) or tactical fighter-bomber role, lacking both payload capability and endurance in comparison with other USAF aircraft. The F-104's U.S. service was quickly wound down after the aircraft's second deployment to southeast Asia in 1967.[90] Although the remaining F-104As in regular USAF service had been recently fitted with more powerful and more reliable J79-GE-19 engines, the last USAF Starfighters left regular Air Force service in 1969.[91] The aircraft continued in use with the Puerto Rico Air National Guard until 1975 when it was replaced in that organization by the A-7 Corsair II.[77][92]

The last use of the F-104 Starfighter in U.S. markings was training pilots for the West German Air Force, with a wing of TF-104Gs and F-104Gs based at Luke Air Force Base, Arizona. Although operated in USAF markings, these aircraft (which included German-built aircraft) were owned by West Germany. They continued in use until 1983.[93]

At dawn on 6 September 1965, Flight Lieutenant Aftab Alam Khan of Pakistan claimed an Indian Dassault Mystère IV over West Pakistan and damaged another, marking the start of aerial combat for the F-104 in the Indo-Pakistani War of 1965. The kill with an AIM-9B Sidewinder is claimed by the Pakistani Air Force (PAF) as the first combat kill by any Mach 2 aircraft and the PAF's first missile kill, though the Indian Air Force (IAF) denied the loss.[94] The Starfighter was also instrumental in intercepting an IAF Folland Gnat on 3 September 1965. F-104s were vectored to intercept the Gnat flying over Pakistan, which was returning to its home base. The F-104s, closing in at supersonic speed, caused the Gnat pilot to land at a nearby disused Pakistani airfield and surrender. The IAF disputed the PAF's claim of forced landing and stated that the landing was an error of the pilot, who made an emergency landing thinking it to be an Indian airstrip. The IAF Gnat is now displayed at the PAF Museum, Karachi.[95][96]

The first direct air-to-air combat engagements between the F-104 and the MiG-21 took place during the Indo-Pakistani War of 1971. MiG-21FLs flown by the IAF shot down at least two, and possibly four, PAF Starfighters without sustaining any losses. The first confirmed loss occurred on 12–13 December 1971, when MiG-21FLs of the IAF's No. 47 Squadron shot down a PAF F-104 of No. 9 Squadron flown by Wing Commander Mervyn Middlecoat over the Gulf of Kutch. The second confirmed PAF F-104 loss occurred several days later on 17 December when Flight Lieutenant Samad Changezi of No. 9 Squadron, flying a Starfighter on loan from Jordan, was shot down by IAF MiG-21FLs of No. 29 Squadron. The IAF also claimed two additional PAF Starfighter kills that same day, one of whom was Changezi's wingman, Squad Leader Rashid Batti; the PAF claimed he was able to return without damage to Masroor.[97][98]

Post-war sanctions forced an early retirement of F-104s from the PAF due to lack of maintenance support.[99]

Republic of China (Taiwan) Air Force F-104J

On 13 January 1967, four Republic of China (Taiwan) Air Force F-104G aircraft engaged a formation of J-6/MiG-19s of the People's Liberation Army Air Force over the disputed island of Kinmen (Quemoy). Major Hu Shih-lin and Captain Shih Bei-puo each shot down one MiG-19. One F-104 did not return to base and its pilot was listed as MIA.[100][101]

F-104 designer Kelly Johnson stated that this particular battle illustrated the relative strengths and weaknesses of the Starfighter in aerial combat. "We had them on acceleration and we had them on steady-state altitude, but we could not turn with them," said Kelly, who at the time was working on the larger-winged, more-maneuverable CL-1200 Lancer derivative of the F-104.[101]

F-104Gs from Marinefliegergeschwader 1, 1965

At the same time that the F-104 was falling out of U.S. favor, the West German Air Force was looking for a multi-role combat aircraft to operate in support of a missile defense system.[102] In response, Lockheed reworked the Starfighter from a fair-weather fighter into an all-weather ground-attack, reconnaissance, and interceptor aircraft, and presented it as the F-104G. The redesigned aircraft was chosen over the English Electric P.1 (later the Lightning), Grumman F11F-1F Super Tiger, Chance Vought F-8U Crusader, and Republic F-105 Thunderchief.[103] The Starfighter found a new market with other NATO countries as well, and eventually a total of 2,578 of all variants of the F-104 were built in the U.S. and abroad for various nations.[104] Several countries received their aircraft under the U.S. government-funded Military Aid Program (MAP).[105] The American engine was retained but built under license in Europe, Canada, and Japan.[106] The Lockheed ejector seats were retained initially but were replaced later in some countries by the safer Martin-Baker seat.[107]

The so-called "Deal of the Century" produced substantial income for Lockheed, but the resulting bribery scandals caused considerable political controversy in Europe and Japan. In 1976, a U.S. Senate investigating committee led by Senator Frank Church determined that Lockheed had paid US$22 million in bribes to foreign officials during the negotiations process of the sale of its aircraft, including the F-104 Starfighter. In Germany, Minister of Defence Franz Josef Strauss was accused of having received at least US$10 million for West Germany's purchase of the F-104 in 1961.[108] On 26 August 1976, Prince-consort Bernhard of the Netherlands was forced to resign as Inspector-General of the Dutch Armed Forces after being accused of accepting approximately US$1.1 million in bribes.[109]

The international service of the F-104 began to wind down in the late 1970s, being replaced in many cases by the General Dynamics F-16 Fighting Falcon, but it remained in service with some air forces for another two decades. The last operational Starfighters served with the Italian Air Force, which retired them on 31 October 2004.[110]

NASA F-15 and F-104 testing Space Shuttle tiles

The Starfighter served with NASA from 1956 until 1994. A total of 12 F-104A, F-104B, F-104N, and TF-104G aircraft performed high-speed and altitude flight research at Dryden Flight Research Center. The F-104 also performed many safety chase missions in support of advanced research aircraft, and provided a launch platform for sounding rockets.[111]

In August 1956, the USAF transferred YF-104A serial number 55-2961 to the National Advisory Committee for Aeronautics (NACA, the predecessor of NASA), designating it NF-104A. In preparation for the X-15 test program of the late 1950s, it was fitted with the reaction control system (RCS) consisting of hydrogen peroxide-powered thrusters mounted in the aircraft's nose and wingtips. This system provided invaluable experience for future X-15 pilots and astronauts in spacecraft control and maneuverability. The trials began in 1959 and concluded in 1961, after which the aircraft was used for other NASA purposes until it was retired in November 1975.[111]

Between August and October 1963, Lockheed delivered three single-seat F-104G Starfighters to NASA, designated F-104N for use as high-speed chase aircraft. These were the only Starfighters built by Lockheed specifically for NASA; all other NASA aircraft were transferred from the USAF. The third of these F-104Ns, number 013, was destroyed on 8 June 1966 in a mid-air collision with a North American XB-70 during a publicity photo flight for General Electric.[111]

One NASA F-104G, registration N826NA, was equipped with a flight test fixture (FTF) consisting of a pylon mounted on the fuselage centerline. The FTF contained instruments to record and transmit the research data in real-time to engineers in mission control at Dryden. One application of the FTF was testing the heat-resistant tiles for use on the Space Shuttle, ensuring their bonding was sufficient at high speeds and evaluating their performance in moisture. The last of these missions flew on 31 January 1994, bringing the F-104's service with NASA Dryden to a close after more than 18,000 flights.[111]

In 2011, 4Frontiers Corporation and Starfighters Inc (a private F-104 operator) began working together on a project to launch suborbital sounding rockets from F-104s flying out of Kennedy Space Center. First launches were expected to occur in 2012.[112][113] As of 16 July 2017, both the 4Frontiers Corporation and Star Lab suborbital websites were unresponsive, and there appeared to be no mention of 4Frontiers or the joint project on the Starfighters Inc website.[114]

In early 2016, another venture, CubeCab, was working on a rocket system that would launch CubeSats from F-104s.[115][116][117] The company said it planned to begin providing launch services "in early 2020".[118]

The F-104 series all had a very high wing loading (made even higher when carrying external stores). During the early stall tests, the aircraft demonstrated the tendency to suddenly "pitch up" once it reached an angle of attack of approximately 15 degrees. This "pitch up" would result in a rapid increase in angle of attack to approximately 60 degrees, accompanied by lateral and directional oscillation, and followed by sudden uncontrolled yaw and roll. At this point the aircraft would be essentially tumbling, descending at a rate of 12,000–15,000 feet per minute (3,700–4,600 m/min).[129] To combat this, an automatic pitch control (APC) was added, which initiated corrective action at the proper time to prevent reaching an angle of attack high enough to cause pitch-up under any operating condition. The high angle of attack area of flight was protected by a stick shaker system to warn the pilot of an approaching stall, and if this was ignored, a stick pusher system would pitch the aircraft's nose down to a safer angle of attack; this was often overridden by the pilot despite flight manual warnings against this practice.[130]

F-104A flight envelope

Another serious design issue that the aircraft encountered was T-tail flutter; Dick Heppe, who served as the initial project aerodynamics engineer for the F-104 program, recalled that "without question, the single most difficult technical challenge encountered in the XF-104 and F-104A development programs was the catastrophic flutter problem of the unique T-tailed empennage configuration." Because the horizontal tail's center of gravity was well aft of both the bending and torsional axes of the vertical tail to which it was attached, it was highly vulnerable to flutter at transonic speeds. During a test flight of the F-104A, the surviving XF-104 was flying chase to observe, and encountered violent T-tail flutter that caused the tail to separate from the aircraft. The test pilot of the XF-104 successfully ejected. This behavior was remedied by increasing the thickness of the stainless steel box covers used in the tail assembly.[131]

The J79 was a brand-new engine, with development continuing throughout the YF-104A test phase and during service with the F-104A. The engine featured variable incidence compressor stator blades, a design feature that altered the angle of the stator blades automatically with altitude and temperature. A condition known as "T-2 reset", a normal function that made large stator blade angle changes, caused several engine failures on takeoff. It was discovered that large and sudden temperature changes (e.g., from being parked in the sun prior to becoming airborne) were falsely causing the engine stator blades to close and choke the compressor. The dangers presented by these engine failures were compounded by the downward ejection seat, which gave the pilot little chance of a safe exit at low level. The engine systems were subsequently modified and the ejection seat changed to the more conventional upward type. Uncontrolled tip-tank oscillations sheared one wing off of an F-104B; this problem was apparent during testing of the XF-104 prototype and was eventually resolved by filling the tank compartments in a specific order.[132]

Early F-104s also lacked modulated afterburning, and as a result combat operations could be performed at one of only two settings, either maximum military power or full afterburner. Effectively this gave the pilot the choice of two level-flight speeds: Mach 1 or Mach 2.2.[133]

A further engine problem was that of uncommanded opening of the variable thrust nozzle (usually through loss of engine oil pressure, as the nozzles were actuated using engine oil as hydraulic fluid); although the engine would be running normally at high power, the opening of the nozzle resulted in a drastic loss of thrust to below that required to maintain level flight. At low altitudes this was unrecoverable, and it caused the loss of at least seven F-104s during testing. A modification program installed a manual nozzle closure control that reduced the problem, but according to designer Kelly Johnson, took nine years to resolve satisfactorily.[134][133]

The engine was also known to suffer from afterburner blowout on takeoff, or even non-ignition, resulting in a major loss of thrust that could be detected by the pilot—the recommended action was to abandon the takeoff. The first fatal accident in German service was caused by this phenomenon. Some aircrews experienced uncommanded "stick kicker" activation at low level when flying straight and level, so F-104 crews were often directed to deactivate it for flight operations.[135] Asymmetric flap deployment was another common cause of accidents, as was a persistent problem with severe nose wheel "shimmy" on landing that usually resulted in the aircraft leaving the runway and in some cases even flipping over onto its back.[136]

West German F-104G with a Zero-length launch rocket booster and a B43 nuclear bomb at Militärhistorisches Museum Flugplatz Berlin-Gatow.

The introduction of a highly technical aircraft type to a newly reformed air force was fraught with problems. Many pilots and ground crew had settled into civilian jobs after World War II and had not kept pace with developments, with pilots being sent on short "refresher" courses in slow and benign-handling first-generation jet aircraft. Ground crew were similarly employed with minimal training and experience, which was one consequence of a conscripted military with high turnover of service personnel. Operating in poor northwest European weather conditions (vastly unlike the fair weather training conditions at Luke AFB in Arizona) and flying low at high speed over hilly terrain, a great many accidents were attributed to controlled flight into terrain (CFIT). German Air Force and Navy losses totaled 110 pilots, around half of them naval officers.[137]

One contributing factor to this was the operational assignment of the F-104 in German service: it was mainly used as a fighter-bomber, as opposed to the original design of a high-speed, high-altitude fighter/interceptor. In addition to the much lower-level mission profiles, the installation of additional avionic equipment in the F-104G version, such as the inertial navigation system, added far more distraction to the pilot and additional weight that further hampered the flying abilities of the plane. In contemporary German magazine articles highlighting the Starfighter safety problems, the aircraft was portrayed as "overburdened" with technology, which was considered a latent overstrain on the aircrews.[138]

In 1966 Johannes Steinhoff took over command of the Luftwaffe and grounded the entire Luftwaffe and Bundesmarine F-104 fleet until he was satisfied that problems had been resolved or at least reduced. In later years, the German safety record improved, although a new problem of structural failure of the wings emerged. Original fatigue calculations had not taken into account the high number of g-force loading cycles that the German F-104 fleet was experiencing, and many airframes were returned to the depot for wing replacement or outright retirement. Towards the end of Luftwaffe service, some aircraft were modified to carry a flight data recorder or "black box" which could give an indication of the probable cause of an accident.[139] Erich Hartmann, the world's top-scoring fighter ace, commanded one of Germany's first (post-war) jet fighter-equipped squadrons[140] and deemed the F-104 to be an unsafe aircraft with poor handling characteristics for aerial combat. In Navy service it lacked the safety margin of a twin engine design like the Blackburn Buccaneer. To the dismay of his superiors, Hartmann judged the fighter unfit for Luftwaffe use even before its introduction.[141]

A German F-104F in 1960. In 1962 this aircraft crashed along with three others after a pilot error.

The causes of a large number of aircraft losses were the same as for any other similar type. They included: bird strikes and other foreign object damage (particularly to the engine), lightning strikes, pilot spatial disorientation, and mid-air collisions with other aircraft.[142] One such accident occurred on 19 June 1962 when a formation of four F-104F aircraft, practicing for the type's introduction-into-service ceremony the following day, crashed together after descending through a cloud bank. The pilot of the lead aircraft lost spatial orientation and was at too steep a nose-down angle to recover. Three German pilots and one American pilot were killed, and the four aircraft destroyed. As a result, formation aerobatic teams were immediately banned by the Luftwaffe from that day forward.[143]

The safety record of the F-104 Starfighter became high-profile news in the mid-1960s, especially in Germany.[144] The Federal Republic of Germany initially ordered 309 F-104s, and over time another 607, for a total of 916 aircraft.[145] Deliveries of Lockheed-built aircraft started in August 1961, and domestically produced airframes began to roll off the assembly lines a few months later in December.[146] That same month, the first of no fewer than 292 German F-104s had crashed.[147] In all, 120 pilots and crew, including 108 German pilots and 8 USAF instructors, died in German F-104s during peacetime between 25 January 1962 and 11 December 1984.[148][149] In October 1975, Lockheed agreed to pay a total of US$1–2 million to approximately 60 widows and dependents of 32 Luftwaffe pilots killed during flight operations, though the company declined to admit liability. While announcing the settlement, the plaintiffs' attorney acknowledged he had been seeking US$10 million and noted that there were more instances of pilot error than he had expected.[150]

The second XB-70 Valkyrie prototype flying in formation with F‑104 (red tail, on the XB‑70's right), 8 June 1966. Shortly after this photograph was taken the F‑104 and XB‑70 collided, killing the F‑104 pilot Joe Walker and the co‑pilot of the XB‑70.

Some operators lost a large proportion of their aircraft through accidents, although the accident rate varied widely depending on the user and operating conditions. The German Air Force and Federal German Navy, the largest combined user of the F-104 and operator of over 35% of all airframes built, lost approximately 32% of its Starfighters in accidents over the aircraft's 31-year career.[151] The Belgian Air Force, on the other hand, lost 41 of its 100 airframes between February 1963 and September 1983,[152] and Italy, the final Starfighter operator, lost 138 of 368 (37%) by 1992.[153] Canada's accident rate with the F-104 ultimately exceeded 46% (110 of 238) over its 25-year service history,[154] though the Canadian jets tended to be flown for a greater number of hours than those of other air forces (three times that of the German F-104s, for example).[155] However, some operators had substantially better accident performance: Denmark's attrition rate for the F-104 was 24%, with Japan losing just 15%[156] and Norway 14% (6 of 43) [157] of their respective Starfighter fleets. The best accident rate was achieved by the Spanish Air Force, which ended its Starfighter era with a perfect safety record. The Ejército del Aire lost none of its 18 F-104Gs and 3 TF-104Gs over a total of seven years and 17,500 flight hours.[158]

The cumulative destroyed rate of the F-104 Starfighter in USAF service as of 31 December 1983 was 25.2 aircraft destroyed per 100,000 flight hours. This is the highest accident rate of any of the USAF Century Series fighters. By comparison, the cumulative destroyed rates for the other Century Series aircraft in USAF service over the same time period were 16.2 for the North American F-100 Super Sabre, 9.7 for the McDonnell F-101 Voodoo, 15.6 for the Republic F-105 Thunderchief, and 7.3 for the Convair F-106 Delta Dart.[159]

Notable USAF pilots who lost their lives in F-104 accidents include Major Robert H. Lawrence Jr.[160] and Captain Iven Kincheloe.[161] Civilian (former USAAF) pilot Joe Walker died in a midair collision with an XB-70 Valkyrie while flying an F-104.[162] Chuck Yeager was nearly killed in December 1963 when he lost control of an NF-104A during a high-altitude record-breaking attempt; he lost the tips of two fingers and was hospitalized for a long period with severe burns after ejecting from the aircraft.[163]

On 2 November 1959, an F-104 crashed into a house in suburban Dayton, Ohio, killing two young girls and critically burning their mother; the pilot had ejected to safety a half-mile away from the crash site.[164]