In the late 1940's, breaking the sound barrier was what everything in the aircraft industry revolved around. On October 14, 1947, Captain Charles "Chuck" Yeager became the first person to achieve supersonic speed in the Bell X-1 "Glamorous Glennis". The next natural development would be getting an operational aircraft that could go supersonic. This happened with the P-86 Sabre - design on which had begun in 1944 - but it could only achieve Mach 1 in a steep dive. This, however, was soon to change with the F-100 Super Sabre built by the very company that built the Sabre; North American Aviation.
At the end of World War II, a lot of data regarding high speed flight and swept-wing design was captured from the Nazis and used as a basis for development of advanced jet aircraft in both the UK, USA and France. The Nazis had done a lot of research on wing design and by trial and error arrived to the conclusion that the most efficient wing design for high speed aircraft had a 45 degree sweep. So, in February 1949, North American Aviation (NAA) began work on a private design which aimed at improving their existing P-86 Sabre in hope of catching USAF's attention. The initial design phase unsurprisingly increased the P-86's (later F-86) sweep-back from 35 to 45 degrees.
Wind tunnel tests showed that the increased wing sweep was not enough to achieve supersonic speed in level flight. A lot more engine power was needed - a lot more than was available in the General Electric J47 engine that the F-86 had. North American started shopping around for engine alternatives for the improved Sabre and was offered the J35 turbojet from Allison and an advanced J47 turbojet from General Electric. Both of these engines were nearly twice as powerful as the original J47. NAA decided to go for the upgraded J47, calculating with a maximum speed of Mach 1.03 at 35000 feet.
NAA proposed the new design in January 1951 to the US Air Force as the "Advanced F-86E" but the generals didn't want it.
NAA went back to their drawing boards and their wind tunnels and came up with a design that improved a few things over the "Advanced F-86E"; the Sabre 45. It was powered by the Pratt & Whitney XJ57 which could push the aircraft through the air at Mach 1.3 at 35000 feet. This time the Pentagon generals accepted the design and on November 7, 1951 issued a Letter Contract for two Sabre 45 prototypes and 110 production aircraft. The Sabre 45 design was officially designated F-100 on December 7, 1951 and it was to become the first of the Century Series of fighters.
Now followed a period with several changes to the original Sabre 45 design. In order to reduce drag, increase engine thrust and make the aircraft behave better while flying supersonic, a number of small but important changes was done to the nose, the tail and the wings. USAF approved the changes and ordered 250 more F-100A's.
The Super Sabre prototypes were the first aircraft to use titanium in important parts of the fuselage, mainly to withstand the heat generated by the supersonic air friction. From 1952 to 1954, NAA used 80% of all the titanium produced in the United States to build the F-100. Because of the use of titanium, the cost per aircraft skyrocketed. Excactly how much the prototypes finally did cost is unknown. The cost for a production Super Sabre was calculated later to around USD 664,000.
On April 24, 1953 the first YF-100A prototype was finished and moved from the NAA factory in Inglewood to Edwards AFB. NAA test pilot George S. Welch broke the sound barrier on its first flight on May 25, 1953. Two weeks later the first production F-100A rolled of the lines, indicative of the speed of the F-100 programme. Test pilots from the USAF went berserk over the new toy, and it was considered the hottest thing in the US Air Force despite a number of problems with supersonic stability and error-prone landings. The stability problems were fixed by enlarging the vertical tail, but the F-100 eventually went on to have one of the worst service records of US military aircraft. For example, over half of the two seat F-100F trainers built were lost to accidents. That fact is quite ironic with regards to the two-seaters raison d'etre; to train green pilots in handling the Super Sabre in a better and safer way.
The F-100 Super Sabre - now nicknamed "The Hun" was making its way into the Air Force and everyone and their uncle wanted to fly it.
World speed records
In order to show off "The Hun", the Air Force wanted to break the world speed record with it. Lieutenant Colonel Frank K. Everest was selected as the record breaking pilot, and on October 19, 1953 he flew with an average speed of 755.149 mph/1215.03 km/h over a 15 km course. The aircraft was never above 100 ft/33 m for the entire course, something no record breaking flight would ever do again.
August 20, 1955: Colonel Horace A. Hanes flew an F-100C at 822.135 mph/1322.8 km/h 40000 feet over the Mojave Desert. This was the first supersonic speed record and the first set at high altitude.
September 4, 1955: In an F-100C, Colonel Carlos Talbott flew from coast to coast in the United States with an average speed of 610.726 mph / 982.6 km/h. Colonel Talbott was awarded the Bendix Trophy for this record setting flight.
Originally, the F-100A was envisioned as a day-only air superiority fighter. This was before the advent of sophisticated radars and computerized air-to-air missiles, so the Hun relied on daylight, high performance and four 20mm Pontiac M-39E cannons. In addition, it had four underwing hardpoints, but they were seldom used for anything but fuel drop tanks. Because of problems with production of F-84F Thunderstreaks, the USAF recommended that a fighter-bomber variant of the Super Sabre being built as the F-100C. On December 20, 1953, USAF ordered 230 new F-100C's and decided that 70 F-100A's should be converted into the C variant. The J57-powered F-100C became the first combat capable Super Sabre to serve in large numbers with the USAF.
Another feature of the C variant was its air-to-air refueling probe. With this, USAF pioneered deployment of aircraft over long distances. With the ability to go overseas on short notice, a number of F-100C Air National Guard squadrons were in October 1961 sent to Europe to augment NATO during the Berlin Crisis.
After the C variant came the D. This obviously had a number of improvements over the C, but the biggest difference was that the Hun no longer was a pure fighter. The F-100C's secondary air-to-air role was outright deleted, effectively making it into a pure fighter-bomber with nuclear weapons capability. In spite of the "bombs only" angle on the D-variant, provisions for Sidewinder air-to-air missiles was later added.
A multitude of technical problems with the F-100D surfaced, and by the early sixties there had been so many in-service modifications done that no two Super Sabres were alike. This naturally proved to be a nightmare in terms of maintenance and spare parts, so the Air Force started project "High Wire" in 1962 to standardize the Super Sabres.
Barn Launch / Zero Length Launch
In the 1950's everyone prepared themselves in one way or another for nuclear war. NATO's take on this took on many shapes, but none so James Bond-esque as the Barn Launch-project. It was officially known as Zero Length Launch (ZEL) and was supposed to be NATOS's ace up their sleeve in case of a surprise nuclear attack.
Put simply, ZEL was a big rocket strapped to the belly of an F-100 that sat in a hardened shelter a long way away from any targeted airfield. The ZEL aircraft was supposed to be launched by means of a 130,000 pound thrust rocket. This was enough to accelerate 16 tons of aircraft to 300mph/482km/h in just four seconds. After the rocket had burnt itself out it was dropped, and the Hun would fly on with its own engine.
The first ZEL launch happened on March 26, 1958 and was a success. The following 19 launches went more or less without trouble, validating the concept. Although ZEL was a simple and reliable concept, it was never used.
The F-100B was supposed to be a faster variant of the F-100A because of the new Pratt & Whitney J57 engine. After a long list of design changes proposed by the USAF had been applied, the result was so different from a Super Sabre that the Air Force issued a new designation; F-107. The F-107 fighter-bomber design eventually found itself in direct competition with the Republic F-105 Thunderchief and lost. In addition, the aircraft was plagued with problems from the beginning, leading to just a brief service with NACA (later NASA) before being relegated to museums.
In May 1962, a number of F-100D's stationed in the Philippines were sent to Thailand to counter Pathet Lao in Laos. In February 1964, F-100's began deploying to South Vietnam, still in support of the Laos campaign. Following the Gulf of Tonkin incident, F-100D's began flying combat air patrols and bombing missions over North Vietnam. It was found however, that North Vietnamese MiG-17's and MiG-21's were superior to the Hun, relegating it to bombing runs and to flee when enemy fighters was encountered. From mid-1965, F-100D's operated only in South Vietnam, leaving the north to the more capable F-4 Phantom and F-105 Thunderchief.
The Hun also served as Forwair Air Controller (FAC) aircraft, marking targets and directing strikes by other aircraft. The missions flown as FAC were dubbed "Misty".
Throughout the late 1960's and the early 1970's, F-100's were gradually withdrawn from service in Vietnam and handed over to the Air National Guard. The last ANG F-100 left for the scrapheap in 1979.
In 1965, several two-seat F-100F's were equipped to identify and attack enemy SAM radar sites in concert with up to four F-105 Thunderchiefs. The project was known as 'Wild Weasel'. Super Sabres in the Wild Weasel role was sucessful, leading to Wild Weasel's being armed with AGM-45 Shrike anti-radiation missiles that gave the Super Sabres the ability to attack radar sites themselves. Towards the end of the 60's, Wild Weasel Super Sabres were replaced by the F-105 Wild Weasel III and the F-4 Wild Weasel IV.
Super Sabres overseas
The Super Sabre served with the air forces of Denmark, Turkey, France and Nationalist China (Taiwan). The first foreign air force to receive the Hun was France's Armee de l'Air. France's Super Sabres were used in combat missions in Algeria, giving the aircraft its baptism of fire. After France's withdrawal from NATO's command structure in 1967, all Super Sabres were handed back to USA and subsequently scrapped.
Turkish Super Sabres came from USAF stocks and a few were ex-Danish. Super Sabres took part in the 1974 fighting over Cyprus, and in 1982 the last Turk Hava Kuvvetleri Hun was retired.
Denmark received 48 single-seaters and ten two-seaters from July 1959 onwards. In the early 1980's they were replaced by F-16A Fighting Falcons. A third of the Royal Danish Air Force's fleet of Super Sabres were lost in accidents, mirroring the types poor safety record in USAF service. An F-100D can be seen guarding the gates at Skrydstrup Air Base in Denmark.
A total of 122 Super Sabres was delivered to Nationalist China (Taiwan) between 1958 and 1962. They were mostly used for intelligence gathering flights over mainland China, an undertaking still shrouded in secrecy. Several Super Sabres were reportedly lost on those missions.
North American Aviation built a total of 2294 Super Sabres at their plants in Inglewood, California and Columbus, Ohio between 1953 and 1959.
- YF-100: Original prototype. 2 built
- F-100A: First production variant. 203 built
- RF-100A: Photo reconnaissance variant. Unknown number converted from F-100A.
- F-100B: Four built as the F-107
- F-100C: Fighter-bomber / fighter. 476 built
- F-100D: Fighter-bomber. 1274 built
- F-100E: Not built
- F-100F: Two-seat trainer variant. 339 built
- QF-100A: Pilotless target drone. 218 converted from various other Super Sabre variants
Technical data is for F-100D
- Engine: One Pratt & Whitney J57-P-21/21A turbojet, 10,200 lb.static dry thrust, 16,000 lb.static thrust with afterburning
- Dimensions: Wingspan 38 ft 9 in/12.7m, length 50 ft/16.5m, height 16 ft 2,75 in/5.33m, wing area 400 sq ft
- Performance: Max speed 770 mph/1239 km/h at sea level (clean), 864 mph (Mach 1.3) at 36000 feet (clean)
- Ceiling: 50000 feet
- Maximum range: 1995 miles / 3210 km
- Weight: 34832 pounds / 15675 kg max takeoff
Wings of Fame, Volume 10, Aerospace Publishing Ltd.
American Warplanes, Bill Gunston, Salamander Books, 1987