North American F-100 Super Sabre


The North American F-100 Super Sabre is an American supersonic jet fighter aircraft that served with the United States Air Force from 1954 to 1971 and with the Air National Guard until 1979. The first of the Century Series of USAF jet fighters, it was the first USAF fighter capable of supersonic speed in level flight. The F-100 was designed by North American Aviation as a higher performance follow-on to the F-86 Sabre air superiority fighter.
Adapted as a fighter-bomber, the F-100 was supplanted by the Mach two-class F-105 Thunderchief for strike missions over North Vietnam. The F-100 flew extensively over South Vietnam as the air force's primary close air support jet until being replaced by the more efficient subsonic LTV A-7 Corsair II. The F-100 also served in other NATO air forces and with other U.S. allies. In its later life, it was often referred to as the Hun, a shortened version of "one hundred".

Design and development

In January 1951, North American Aviation delivered an unsolicited proposal for a supersonic day fighter to the United States Air Force. Named Sabre 45 because of its 45° wing sweep, it represented an evolution of the F-86 Sabre. The mockup was inspected on 7 July 1951, and after over a hundred modifications, the new aircraft was accepted as the F-100 on 30 November 1951. Extensive use of titanium throughout the aircraft was notable. On 3 January 1952, the USAF ordered two prototypes followed by 23 F-100As in February and an additional 250 F-100As in August.
The YF-100A first flew on 25 May 1953, seven months ahead of schedule. It reached Mach 1.04 in spite of being fitted with a de-rated XJ57-P-7 engine. The second prototype flew on 14 October 1953, followed by the first production F-100A on 9 October 1953. The USAF operational evaluation from November 1953 to December 1955 found the new fighter to have superior performance, but declared it not ready for wide-scale deployment due to various deficiencies in the design. These findings were subsequently confirmed during "Project Hot Rod" operational suitability tests.
Six F-100s arrived at the Air Proving Ground Command, Eglin Air Force Base in August 1954. The Air Force Operational Test Center was scheduled to use four of the fighters in operational suitability tests and the other two were to undergo armament tests by the Air Force Armament Center. The Tactical Air Division of AFOTC was conducting the APGC testing under the direction of project office Lieutenant Colonel Henry W. Brown. Initial testing was completed by APGC personnel at Edwards Air Force Base.
Particularly troubling was the yaw instability in certain regimes of flight which produced inertia coupling. The aircraft could develop a sudden yaw and roll which would happen too fast for the pilot to correct and would quickly over-stress the aircraft structure to disintegration. It was under these conditions that North American's chief test pilot, George Welch, was killed while dive testing an early-production F-100A on 12 October 1954.
Another control problem stemmed from handling characteristics of the swept wing at high angles of attack. As the aircraft approached stall speeds, loss of lift on the tips of the wings caused a violent pitch-up. This particular phenomenon became known as the "Sabre dance".
Nevertheless, delays in the Republic F-84F Thunderstreak program pushed the Tactical Air Command to order the raw F-100A into service. Tactical Air Command also requested that future F-100s be fighter-bombers, with the capability of delivering nuclear bombs.
The North American F-107 was a follow-on Mach 2 development of the F-100 with the air intake moved above and behind the cockpit. It was not produced in favor of the Republic F-105 Thunderchief.

Operational history

The F-100A officially entered USAF service on 27 September 1954, with the 479th Fighter Wing at George AFB, California. By 10 November 1954, the F-100As suffered six major accidents due to flight instability, structural failures, and hydraulic system failures, prompting the air force to ground the entire fleet until February 1955. The 479th finally became operational in September 1955. Due to ongoing problems, the air force began phasing out the F-100A in 1958, with the last aircraft leaving active duty in 1961. By that time, 47 aircraft had been lost in major accidents. Escalating tension due to construction of the Berlin Wall in August 1961 forced the USAF to recall the F-100As into active service in early 1962. The aircraft was finally retired in 1970.
The TAC request for a fighter-bomber was addressed with the F-100C which flew in March 1954 and entered service on 14 July 1955, with the 450th Fighter Wing, Foster AFB, Texas. Operational testing in 1955 revealed that the F-100C was at best an interim solution, sharing all the flaws of the F-100A. The uprated J57-P-21 engine boosted performance but continued to suffer from compressor stalls. However, the F-100C was considered an excellent platform for nuclear toss bombing because of its high top speed. The inertia coupling problem was reasonably addressed with the installation of a yaw damper in the 146th F-100C, later retrofitted to earlier aircraft. A pitch damper was added starting with the 301st F-100C, at a cost of US$10,000 per aircraft.
The addition of "wet" hardpoints meant the F-100C could carry a pair of 275 U.S. gal and a pair of 200 U.S. gal drop tanks. However, the combination caused a loss of directional stability at high speeds and the four tanks were soon replaced by a pair of 450 U.S. gal drop tanks. The 450s proved scarce and expensive and were often replaced by smaller 335 US gal tanks. Most troubling to TAC was the fact that, as of 1965, only 125 F-100Cs were capable of utilizing all non-nuclear weapons in the air force inventory, particularly cluster bombs and AIM-9 Sidewinder air-to-air missiles. By the time the F-100C was phased out in June 1970, 85 had been lost in major accidents.
The definitive F-100D aimed to address the offensive shortcomings of the F-100C by being primarily a ground attack aircraft with secondary fighter capabilities. To this effect, the aircraft was fitted with autopilot, upgraded avionics, and, starting with the 184th production aircraft, AIM-9 Sidewinder capability. In 1959, 65 aircraft were modified to also fire the AGM-12 Bullpup air-to-ground missile. To further address the dangerous flight characteristics, the wing span was extended by 26 in and the vertical tail area was increased by 27%.
The first F-100D flew on 24 January 1956, piloted by Daniel Darnell. It entered service on 29 September 1956 with the 405th Fighter Wing at Langley AFB. The aircraft suffered from reliability problems with the constant speed drive which provides constant-frequency current to the electrical systems. In fact, the drive was so unreliable that the USAF required it to have its own oil system to minimize damage in case of failure. Landing gear and brake parachute malfunctions claimed a number of aircraft, and the refueling probes had a tendency to break away during high speed maneuvers. Numerous post-production fixes created such a diversity of capabilities between individual aircraft that, by 1965, around 700 F-100Ds underwent High Wire modifications to standardize the weapon systems. High Wire modifications took 60 days per aircraft at a cost for the entire project of US$150 million. In 1966, the Combat Skyspot program fitted some F-100Ds with an X band radar transmitter to allow for ground-directed bombing in inclement weather or at night.
In 1961, at England AFB, Louisiana,, there were four fighter-bomber squadrons. These were the 612th, 613th, 614th and the 615th. During the Berlin Crisis the 614th was deployed to Ramstein Air Base, Germany, to support the West Germans. At the initial briefing, the 614th personnel were informed that, due to the close proximity of the USSR, if an ICBM were to be launched, they would have only 30 minutes to launch the 614th's aircraft and retire to the nearest German bunker.
In 1967, the USAF began a structural reinforcement program to extend the aircraft's service life from the designed 3,000 flying hours to 7,000. The USAF alone lost 500 F-100Ds, predominantly in accidents. After one aircraft suffered wing failure, particular attention was paid to lining the wings with external bracing strips. During the Vietnam War, combat losses constituted as many as 50 aircraft per year. On 7 June 1957, an F-100D fitted with an Astrodyne booster rocket making 150,000 lbf of thrust successfully performed a zero length launch. This was accomplished with the addition of a large canister to the underside of the aircraft. This canister contained a black powder compound and was ignited electro-mechanically, driving the jet engine to minimal ignition point. The capability was incorporated into late-production aircraft. After a major accident, the USAF Thunderbirds reverted from F-105 Thunderchiefs to the F-100D which they operated from 1964 until it was replaced by the F-4 Phantom II in 1968.
The F-100 was the subject of many modification programs over the course of its service. Many of these were improvements to electronics, structural strengthening, and projects to improve ease of maintenance. One of these was the replacement of the original afterburners of the J-57 engines with the more advanced afterburners from retired Convair F-102 Delta Dagger interceptors. This modification changed the appearance of the aft end of the F-100, doing away with the original "petal-style" exhaust. The afterburner modification started in the 1970s and solved maintenance problems with the old type as well as operational problems, including compressor stall issues.
The F-100F two-seat trainer entered service in 1958. It received many of the same weapons and airframe upgrades as the F-100D, including the new afterburners. By 1970, 74 F-100Fs were lost in major accidents.
By 1972, the F-100 was mostly phased out of USAF active service and turned over to tactical fighter groups and squadrons in the ANG. In Air National Guard units, the F-100 was eventually replaced by the F-4 Phantom II, LTV A-7 Corsair II, and A-10 Thunderbolt II, with the last F-100 retiring in 1979, with the introduction of the F-16 Fighting Falcon. In foreign service, the Royal Danish Air Force and Turkish Air Force F-100s soldiered on until 1982.
Over the lifetime of its USAF service, a total of 889 F-100 aircraft were destroyed in accidents, involving the deaths of 324 pilots. The deadliest year for F-100 accidents was 1958, with 116 aircraft destroyed, and 47 pilots killed.
After Super Sabres were withdrawn from service, a large number were converted into remote-controlled drones under the USAF Full Scale Aerial Target program for use as targets for various anti-aircraft weapons, including missile-carrying fighters and fighter-interceptors, with FSAT operations being conducted primarily at Tyndall AFB, Florida. A few F-100s also found their way into civilian hands, primarily with defense contractors supporting USAF and NASA flight test activities at Edwards AFB, California.

Project Slick Chick

North American received a contract to modify six F-100As to RF-100As carrying five cameras, three Fairchild K-17 cameras in a trimetrogon mounting for photo-mapping and two Fairchild K-38 cameras in a split vertical mounting with the cameras mounted horizontally, shooting via a mirror angled at 45° to reduce the effects of airframe vibrations. All gun armament was removed and the cameras installed in the gun and ammunition bays covered by a bulged fairing under the forward fuselage.
The selected pilots trained on the F-100A at Edwards Air Force Base and George Air Force Base in California and then at Palmdale Air Force Base for training with the actual RF-100As they would be deployed with. Flight tests revealed that the RF-100A in its intended operational fit of four external tanks was lacking in directional and longitudinal stability, requiring careful handling and close attention to speed limitations for the drop tanks.
Once pilot training was completed in April 1955, three aircraft were deployed to Bitburg Air Base in Germany, flying to Brookley AFB in Mobile, Alabama, cocooned, loaded on an aircraft carrier and delivered to Short Brothers at Sydenham, Belfast, for re-assembly and preparation for flight. At Bitburg they were allocated to Detachment 1 of the 7407th Support Squadron, and commenced operations flying over Eastern Bloc countries at high altitude to acquire intelligence on military targets. Many attempts were made to intercept these aircraft to no avail, with some photos of fighter airfields clearly showing aircraft climbing for attempted intercepts. The European detachment probably only carried out six missions between mid-1955 and mid-1956 when the Lockheed U-2 took over as the deep penetration aerial reconnaissance asset.
Three RF-100As were also deployed to the 6021st Reconnaissance Squadron at Yokota Air Base in Japan, but details of operations there are not available. Two RF-100A aircraft were lost in accidents, one due to probable overspeeding which caused the separation of one of the drop tanks and resulted in complete loss of control, and the other due to an engine flame-out. In mid-1958, all four remaining RF-100As were returned to the US and later supplied to the Republic of China Air Force in Taiwan.

Project High Wire

"High Wire" was a modernization program for selected F-100Cs, Ds and Fs. It comprised two modifications: an electrical rewiring upgrade, and a heavy maintenance and IRAN upgrade. Rewiring upgrade operations consisted of replacing old wiring and harnesses with improved maintainable designs. Heavy maintenance and IRAN included new kits, modifications, standardized configurations, repairs, replacements and complete refurbishment.
This project required all new manuals and incremented block numbers. All later production models, especially the F models, included earlier High Wire modifications. New manuals included colored illustrations and had the Roman numeral added after the aircraft number.
Total production 2,294

Vietnam War

Fighter and Close Air Support missions

On 16 April 1961, six Super Sabres were deployed from Clark Air Base in the Philippines to Don Muang Royal Thai Air Force Base in Thailand for air defense purposes; the first F-100s to enter combat in Southeast Asia. From that date until their redeployment in 1971, the F-100s were the longest serving U.S. jet fighter-bomber to fight in the Vietnam War. Serving as MiG combat air patrol escorts for F-105 Thunderchiefs, Misty FACs, and Wild Weasels over North Vietnam, and then relegated to close air support and ground attacks within South Vietnam.
On 18 August 1964, the first F-100D shot down by ground fire, piloted by 1st Lt Colin A. Clarke, of the 428th TFS; Clarke ejected and survived.
On 4 April 1965, as escorts protecting F-105s attacking the Thanh Hoa Bridge, F-100 Super Sabres fought the USAF's first air-to-air jet combat duel in the Vietnam War, in which an F-100 piloted by Captain Donald W. Kilgus of the 416th Fighter Squadron shot down a Vietnam People's Air Force MiG-17, using cannon fire, while another fired AIM-9 Sidewinder missiles. The surviving North Vietnamese pilot confirmed three of the MiG-17s had been shot down. Although recorded by the U.S. Air Force as a probable kill, this represented the first aerial victory by the U.S. Air Force in Vietnam. However, the small force of four MiG-17s had penetrated the escorting F-100s to claim two F-105s.
The F-100 was soon replaced by the F-4C Phantom II for MiG CAP which pilots noted suffered for lacking built-in guns for dogfights.
The Vietnam War was not known for utilizing activated Army National Guard, Air National Guard or other U.S. Reserve units; but rather, had a reputation for conscription during the course of the war. During a confirmation hearing before Congress in 1973, Air Force General George S. Brown, who had commanded the 7th Air Force during the war, stated that five of the best Super Sabre squadrons in Vietnam were from the Air National Guard. This included the of the Colorado Air National Guard, the 136 TFS of the New York Air National Guard TFS, the 174 TFS of the Iowa Air National Guard and the 188 TFS of the New Mexico Air National Guard. The fifth unit was a regular AF squadron manned by mostly air national guardsmen.
The Air National Guard F-100 squadrons increased the regular USAF by nearly 100 Super Sabres in theater, averaging, for the Colorado ANG F-100s, 24 missions a day, delivering ordnance and munitions with a 99.5% reliability rate. From May 1968 to April 1969, the ANG Super Sabres flew more than 38,000 combat hours and more than 24,000 sorties. Between them, at the cost of seven F-100 Air Guard pilots killed and the loss of 14 Super Sabres to enemy action, the squadrons expended over four million rounds of 20mm shells, 30 million pounds of bombs and over 10 million pounds of napalm against their enemy.
The Hun was also deployed as a two-seat F-100F model which saw service as a "fast FAC" or Misty FAC in South Vietnam and Laos, spotting targets for other fighter-bomber aircraft, performing road reconnaissance, and conducting Search And Rescue missions as part of the top-secret Commando Sabre project, based out of Phu Cat and Tuy Hoa air bases.
By the war's end, 242 F-100 Super Sabres had been lost in Vietnam, as the F-100 was progressively replaced by the F-4 Phantom II and the F-105 Thunderchief. The Hun had logged 360,283 combat sorties during the war and its wartime operations came to end on 31 July 1971. The four fighter wings with F-100s flew more combat sorties in Vietnam than over 15,000 P-51 Mustangs flew during World War II. After 1965, they did not fly into North Vietnam and mainly performed close air support missions. Despite the April 1965 dogfight, the air force classified the engagement as resulting in a "probable" kill, and no F-100 was ever officially credited with any aerial victories. No F-100 in Vietnam was lost to enemy fighters, but 186 were shot down by anti-aircraft fire, seven were destroyed from Vietcong attacks on airbases, and 45 crashed in operational incidents.

Wild Weasel

The F-100 was also the first Wild Weasel air defense suppression aircraft, whose specially trained crews were tasked with locating and destroying enemy missile defenses. Four F-100F Wild Weasel Is were fitted with an APR-25 vector radar homing and warning receiver, IR-133 panoramic receivers with greater detection range, and KA-60 panoramic cameras. The APR-25 could detect early-warning radars and emissions from SA-2 Guideline tracking and guidance systems. These aircraft deployed to Korat Royal Thai Air Force Base, Thailand, in November 1965, began flying combat missions with the 388th Tactical Fighter Wing in December. They were joined by three more aircraft in February 1966. All Wild Weasel F-100Fs were eventually modified to fire the AGM-45 Shrike anti-radiation missile.

Algerian war

French Air Force Super Sabres of the EC 1/3 Navarre flew combat missions, striking from bases within France against targets in Algeria. The planes were based at Reims, refuelling at Istres on the return flight from Algeria. The F-100 was the main fighter-bomber in the French Air Force during the 1960s, until it was replaced by the Jaguar.

Turkey

Turkish Air Force F-100 units were used during the Turkish invasion of Cyprus in 1974. Together with F-104G Starfighters, they provided close air support to Turkish ground troops and bombed targets around Nicosia. In March 1987, Turkish Super Sabres bombed Kurdish bases in Northern Iraq.

Taiwan

Taiwan took delivery of 119 F-100As, 4 RF-100As and 14 F-100Fs and lost a number of F-100As and Fs in the course of service, but never lost a single RF-100As in either combat or accident. Those four RF-100As had never been sent on reconnaissance mission over mainland China as they could only produce photographic images of mediocre quality at best. Moreover, after each flying hour, the ground personnel had to spend over hundred hours on the aircraft maintenance. All of the RF-100As were returned to the US after one year and 11 months in ROCAF service.

Achievements

Source: Knaack
The costs are in contemporary United States dollars and have not been adjusted for inflation.

Variants

;YF-100A
;YQF-100
;F-100A
;RF-100A
;F-100B
;F-100BI
;F-100C
;TF-100C
;F-100D
;F-100F
;DF-100F
;NF-100F
;TF-100F
;QF-100
;F-100J
;F-100K
;F-100L
;F-100N
;F-100S

Operators

;

Denmark

;F-100F
;F-100D
;F-100D
;F-100F
;F-100D
;F-100D
;F-100A
;F-100C
;F-100D
;F-100F
;F-100D
;F-100F
;Airworthy
;;F-100F
;On display
;;YF-100A
;;F-100A
;;F-100C
;;F-100D
;;F-100F