North American YF-100A “Super Sabre”
The YF-100A “Super Sabre” 5
The North American F-100 “Super Sabre” was the first supersonic operational fighter to be developed for the United States Air Force. The prototype North American YF-100A “Super Sabre” (AF 52-5754) powered by a Pratt & Whitney J57-P-7 turbojet engine fitted with an afterburner flew for the first time on 25 May 25 1953. It exceeded the speed of sound in level flight on its first 35-minutes flight.
Archive Photos 1,6
North American YF-100A “Super Sabre” (Photos via references 1 and 6)
The North American F-100 “Super Sabre” was a supersonic jet fighter aircraft that served with the United States Air Force (USAF) from 1954 to 1971 and with the Air National Guard (ANG) until 1979. The first of the Century Series collection of USAF jet fighters, it was the first USAF fighter capable of supersonic speed in level flight. The North American F-100 “Super Sabre” was originally designed by North American Aviation as a higher performance follow-on to the North American F-86 “Sabre” air superiority fighter.
Adapted as a fighter bomber, the North American F-100 “Super Sabre” would be supplanted by the Mach 2 class Republic F-105 “Thunderchief” for strike missions over North Vietnam. The North American F-100 “Super Sabre” flew extensively over South Vietnam as the Air Force's primary close air support jet until replaced by the more efficient subsonic LTV A-7 “Corsair II”. The North American F-100 “Super Sabre” 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 ¹
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 North American F-86 “Sabre”. The mock-up was inspected 7 July 1951 and after over a hundred modifications, the new aircraft was accepted as the North American F-100 “Super Sabre” on 30 November 1951. Extensive use of titanium throughout the aircraft was notable. On 3 January 1952, the USAF ordered two prototypes followed by twenty-three North American F-100A “Super Sabres” in February and an additional 250 North American F-100A “Super Sabres” in August.
The North American YF-100A “Super Sabre” first flew on 25 May 1953, seven months ahead of schedule. It reached Mach 1.05 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 North American F-100A “Super Sabre” 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. 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 North American F-100A “Super Sabre” 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 (which could easily be fatal at low altitude where there was insufficient time to recover) became known as the "Sabre Dance".
Nevertheless, delays in the Republic F-84F “Thunderstreak” program pushed the Tactical Air Command to order the raw North American F-100A “Super Sabre” into service. TAC also requested that future North American F-100 “Super Sabres” should be fighter-bombers, with the capability of delivering nuclear bombs.
The North American YF-107A “Ultra Sabre” was a follow-on Mach 2 development of the North American F-100 “Super Sabre” with the air intake moved above and behind the cockpit. It was not developed in favor of the Republic F-105 “Thunderchief”.
Operational History ¹
The North American F-100 “Super Sabre”A officially entered USAF service on 27 September 1954 with 479th Fighter Wing at George AFB, California. By 10 November 1954, the North American F-100A “Super Sabre” 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 North American F-100A “Super Sabre” in 1958, with the last aircraft leaving active duty in 1961. By that time, 47 aircraft were lost in major accidents. Escalating tension due to construction of the Berlin Wall in August 1961 forced the USAF to recall the North American F-100A “Super Sabres” into active service in early 1962. The aircraft was finally retired in 1970.
The TAC request for a fighter-bomber was addressed with The North American F-100C “Super Sabre” 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 North American F-100C “Super Sabre” was at best an interim solution, sharing all the vices of the North American F-100A “Super Sabre”. The uprated J57-P-21 engine boosted performance but continued to suffer from compressor stalls. On a positive note, the North American F-100C “Super Sabre” was considered an excellent platform for nuclear toss bombing because of its high top speed. The inertia coupling problem was more or less addressed with installation of a yaw damper in the 146th North American F-100C “Super Sabre”, later retrofitted to earlier aircraft. A pitch damper was added starting with the 301st North American F-100C “Super Sabre”, at a cost of US$10,000 per aircraft.
The addition of "wet" hardpoints meant the North American F-100C “Super Sabre” could carry a pair of 275 U.S. gal (1,040 liter) and a pair of 200 U.S. gal (770 liter) drop tanks. However, the combination caused loss of directional stability at high speeds and the four tanks were soon replaced by a pair of 450 U.S. gal (1,730 liter) drop tanks. The 450's proved scarce and expensive and were often replaced by smaller 335 US gal (1,290 liter) tanks. Most troubling to TAC was the fact, that, as of 1965, only 125 North American F-100C “Super Sabres” 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 North American F-100C “Super Sabre” was phased out in June 1970, 85 had been lost in major accidents.
The definitive North American F-100D “Super Sabre” aimed to address the offensive shortcomings of the North American F-100C “Super Sabre” by being primarily a ground attack aircraft with secondary fighter capability. To this effect, the aircraft was fitted with autopilot, upgraded avionics, and, starting with the 184th production aircraft, the “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 (66 cm) and the vertical tail area was increased by 27%.
The first North American F-100D “Super Sabre” (AF 54-2121) flew on 24 January 1956, piloted by Daniel Darnell. It entered service on 29 September 1956 with 405th Fighter Wing at Langley AFB. The aircraft suffered from reliability problems with the constant speed drive which provides constant-frequency current to electrical systems. In fact, the drive was so unreliable that 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 North American F-100D “Super Sabres” underwent High Wire modifications to standardize the weapon systems. High Wire modifications took 60 days per aircraft at a total cost of US$150 million. In 1966, Combat Skyspot program fitted some North American F-100D “Super Sabres” with an X band radar transmitter to allow for ground-directed bombing in inclement weather or at night.
In 1961, at England AFB, Louisiana, (401st Tactical Wing), there were four fighter-bomber squadrons. These were the 612th, 613th, 614th and the 615th (Fighting Tigers). During the Berlin Crisis (approximately September 1961) 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 only have 30 minutes to launch the 614th 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. USAF alone lost 500 North American F-100D “Super Sabres”, 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, a North American F-100D “Super Sabre” fitted with an Astrodyne booster rocket making 150,000 lbf (667.2 kN) 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 Republic F-105 “Thunderchiefs” to the North American F-100D “Super Sabre” which they operated from 1964 until it was replaced by the McDonnell Douglas F-4 “Phantom II” in 1968.
The North American F-100 “Super Sabre” 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 the more interesting of these was the replacement of the original afterburner of the J-57 engine with the more advanced afterburners from retired Convair F-102 “Delta Dagger” interceptors. This modification changed the appearance of the aft end of the North American F-100 “Super Sabre”, doing away with the original “petal-style” exhaust. The afterburner modification started in the 1970's and solved maintenance problems with the old type as well as operational problems, including compressor stall issues.
The North American F-100F “Super Sabre” two-seat trainer entered service in 1958. It received many of the same weapons and airframe upgrades as the North American F-100D “Super Sabre”, including the new afterburners. By 1970, 74 North American F-100F “Super Sabres” were lost in major accidents.
By 1972, the North American F-100 “Super Sabre” 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 North American F-100 “Super Sabre” was eventually replaced by the McDonnell Douglas F-4 “Phantom II”, LTV A-7 “Corsair II”, and Republic A-10 “Thunderbolt II”, with the last North American F-100 “Super Sabre” retiring in 1979, with the introduction of the General Dynamics F-16 “Fighting Falcon”. In foreign service, Royal Danish Air Force and Turkish Air Force North American F-100 “Super Sabres” soldiered on until 1982.
Over the lifetime of its USAF service, a total of 889 North American F-100 “Super Sabre” aircraft were destroyed in accidents, involving the deaths of 324 pilots. The deadliest year for North American F-100 “Super Sabre” accidents was 1958, with 116 aircraft destroyed, and 47 pilots killed.
After North American F-100 “Super Sabres” were withdrawn from service, a large number were converted into remote-controlled drones (QF-100) under the USAF Full Scale Aerial Target (FSAT) 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, FL. A few North American F-100 “Super Sabres” also found their way into civilian hands, primarily with defense contractors supporting USAF and NASA flight test activities at Edwards AFB, CA.
Project Slick Chick ¹
North American received a contract to modify six North American F-100A “Super Sabres” to North American RF-100A “Super Sabres” carrying five cameras, three K-17's in a trimetrogon mounting for photo-mapping and two K-38's 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 North American F-100A “Super Sabre” at Edwards AFB and George AFB in California and then at Palmdale for training with the actual North American RF-100A “Super Sabres” they would be deployed with. Flight tests revealed that the North American RF-100A “Super Sabre” 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/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 (over 50,000 ft) 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 reconnaissance asset.
Three North American RF-100A “Super Sabres” were also deployed to the 6021st Reconnaissance Squadron at Yokota Air Base in Japan, but details of operations there are not available. Two North American RF-100A “Super Sabres” were lost in accidents, one due to probable over speeding 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 North American RF-100A “Super Sabres” were returned to the USA and later supplied to the Republic of China Air Force in Taiwan.
Project High Wire ¹
Project “High Wire” was a modernization program for selected North American F-100C, F-100D and F-100F “Super Sabres”. It consisted of two modifications - electrical rewiring upgrade, and heavy maintenance and IRAN upgrade. Rewiring upgrade operation consisted of replacing old wiring and harnesses with improved maintainable designs. Heavy maintenance and IRAN (inspect and repair as necessary) included new kits, modifications, standardized configurations, repairs, replacements and complete refurbishment.
This project required all new manuals (TO's) and incremented (i.e. -85 to -86) block numbers. All later production models, especially the North American F-100F “Super Sabre” models included earlier High Wire mods. New manuals included colored illustrations and had the Roman numeral (I) added after the aircraft number (i.e. T.O. 1F-100D(I)-1S-120, 12 January 1970). Total Production was 2,294.
Vietnam War ¹
On 16 April 1961 six North American F-100 “Super Sabres” were deployed from Clark Air Base in the Philippines to Don Muang Airfield in Thailand for air defense purposes; the first North American F-100 “Super Sabres” to enter combat in Southeast Asia. From that date until their redeployment in 1971, the North American F-100 “Super Sabres” would be the longest serving U.S. jet fighter-bomber to fight in the Vietnam War. Serving as MiGCAP escorts for Republic F-105 “Thunderchiefs”, “MISTY” FAC's, 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 North American F-100D “Super Sabre” to be shot down by ground fire was piloted by 1st Lt Colin A. Clarke, of the 428th TFS; Clarke ejected and survived. On 4 April 1965, as escorts protecting Republic F-105 “Thunderchiefs” attacking the Thanh Hoa Bridge, North American F-100 “Super Sabres” fought the USAF's first air-to-air jet combat duel in the Vietnam War, in which a North American F-100 “Super Sabre” piloted by Capt Donald W. Kilgus shot down a North Vietnamese Air Force Mikoyan-Gurevich MiG-17 “Fresco”, using cannon fire, while another fired “Sidewinder” missiles. The surviving North Vietnamese pilot confirmed three of the Mikoyan-Gurevich MiG-17 “Fresco” 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 Mikoyan-Gurevich MiG-17 “Frescos” had penetrated the escorting North American F-100 “Super Sabres” to claim two Republic F-105 “Thunderchiefs”. The North American F-100 “Super Sabre” was soon replaced by the McDonnell Douglas 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 (military draft) during the course of the war. During a confirmation hearing before Congress in 1973, USAF General George S. Brown, who had commanded the 7th Air Force (7 AF) during the war, stated that five of the best North American F-100 “Super Sabre” squadrons in Vietnam were from the ANG. This included the 120th Tactical Fighter Squadron (120 TFS) 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 North American F-100 “Super Sabre” Squadrons increased the regular USAF by nearly 100 North American F-100 “Super Sabres” in theater, averaging, for the Colorado ANG North American F-100 “Super Sabres”, 24 missions a day, delivering ordnance and munitions with a 99.5% reliability rate. From May 1968 to April 1969, the ANG North American F-100 “Super Sabres” flew more than 38,000 combat hours and more than 24,000 sorties. Between them, at the cost of seven North American F-100 “Super Sabre” Air Guard pilots killed (plus one staff officer) and the loss of 14 North American F-100 “Super Sabres” to enemy action, the squadrons expended over four million rounds of 20-mm cannon, 30 million pounds of bombs and over 10 million pounds of napalm against the enemy.
The “Hun” was also deployed as a two-seat North American F-100F “Super Sabre” model which saw service as a “Fast FAC” or “Misty FAC” (forward air controller) in North Vietnam and Laos, spotting targets for other fighter-bomber aircraft, performing road reconnaissance, and conducting SAR (Search and Rescue) missions as part of the top-secret project “Commando Sabre”, based out of Phu Cat and Tuy Hoa Air Bases. It was also the first “Wild Weasel” SEAD (air defense suppression) aircraft whose specially-trained crews were tasked with locating and destroying enemy air defenses. Four North American F-100F “Wild Weasel I's” were fitted with an APR-25 vector radar homing and warning (RHAW) receivers, IR-133 panoramic receivers with greater detection range, and KA-60 panoramic cameras. The APR-25 could detect early-warning radars and, more importantly, emissions from SA-2 “Guideline” tracking and guidance systems. These aircraft deployed to Korat Royal Thai Air Force Base, Thailand in November 1965, and began flying combat missions with the 388th Tactical Fighter Wing in December. They were joined by three more aircraft in February 1966. All North American F-100F “Wild Weasels” were eventually modified to fire the AGM-45 “Shrike” anti-radiation missile.
By war's end, 242 North American F-100 “Super Sabres” had been lost in Vietnam, as the North American F-100 “Super Sabre” was progressively replaced by the McDonnell Douglas F-4 “Phantom II” and the Republic 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.
Algerian War ¹
French Air Force Super Sabres might have flown combat missions, with strikes flown from bases within France against targets in Algeria. The planes were based at Rheims, refueling at Istres on return flight from attacking targets in Algeria. The North American F-100 “Super Sabre” was the main fighter bomber in French Air Force during the 1960's, until replaced by the BAC “Jaguar”.
Cyprus Crisis ¹
Turkish Air Force North American F-100 “Super Sabre” units were used during the operation against EOKA in 1974. Together with Lockheed F-104G “Starfighters”, they provided close air support to Turkish ground troops and bombed targets around Nicosia.
Notable Achievements ¹
F-100 Variants ¹
Republic of China (Taiwan)
French Republic (République Française)
Republic of Turkey (Türkiye Cumhuriyeti)
North American F-100 “Super Sabre” Production ³
Specifications (YF-100A) 3,4