[4] Initially referred to as the Sabre 45, it was delivered as an unsolicited proposal to the USAF in January 1951, leading to two prototypes being ordered one year later following modifications.

Flight testing demonstrated both the F-100's promising performance and several deficiencies, which included its tendency of yaw instability and inertia coupling that led to numerous fatal accidents.

On 27 September 1954, the F-100A officially entered USAF service, however, as a result of six major accidents occurred by 10 November 1954, the type was grounded while investigations and remedial work were conducted.

Amid a relatively high attrition rate and the arrival of more advanced fighters, the USAF opted to permanently withdraw its remaining F-100s during the early 1970s.

In January 1951, the company delivered an unsolicited proposal for a supersonic day fighter to the United States Air Force (USAF).

During October 1951, the Air Force Council advocated for the development of a refined model of the Sabre 45; furthermore, it agreed with the Aircraft and Weapons Board's recommendation that it be purchased in quantity even prior to flight testing despite the risks involved in this approach.

[8] By mid-November 1951, in excess of 100 aircraft configuration change requests had been received, necessitating numerous modifications to the original design; several of these alterations were focused on its armaments and were intended to improve its lethality.

[9] Around this time, development work slowed considerably while North American focused on improving and ramping up production of the F-86 in response to urgent demands for more aircraft to participate in the Korean War.

[8] On 25 May 1953, North American Aviation Chief Test Pilot George Welch conducted the first flight of the YF-100A, seven months ahead of schedule.

By September, flight testing had confirmed the presence of three major deficiencies in the design, all of which required correction ahead of it being considered as acceptable.

[13] Accordingly, during December 1953, the Air Council opted to alter the program, reducing the outstanding total orders for the F-100A by 70 aircraft in favor of a new fighter-bomber variant that would be capable of delivering nuclear bombs.

However, the difficulties experienced with the F-100A were viewed as evidence that the aircraft, even in the face of expected improvements, would be incapable of satisfying the operational requirement to a greater degree than that of the F-102.

During May 1954, the TAC had requested a more sophisticated fighter-bomber; the company aimed to address the offensive shortcomings of the F-100C by being primarily a ground-attack aircraft with secondary fighter capabilities.

[21] In December 1954, a new General Operational Requirement, GOR 68, was issued by the USAF; it called for a tactical fighter-bomber that would also be effective as an aerial superiority fighter under both day and night conditions.

[23] Unlike modern stabilators which use an anti-servo tab, gearing and a variable stiffness spring were attached to the control stick to provide acceptable resistance to prevent pilot-induced oscillation.

Several early modifications were made to address the problem, including the integration of black boxes with the yaw and pitch axis, the reshaping of the vertical tail surfaces, shortening of the tailfin, and increased chord of the rudder.

[citation needed] On 27 September 1954, the F-100A officially entered USAF service with the 479th Fighter Wing, based at George AFB, California.

[27] However, as a result of escalating world tensions in response to the Berlin Wall's construction in August 1961, the USAF was compelled to recall the F-100As into active service.

The uprated J57-P-21 engine boosted performance, although it continued to suffer from compressor stalls, but the F-100C was considered an excellent platform for nuclear toss bombing because of its high top speed.

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.

Various modifications, largely focused on the structure, were made during the F-100F's service life; several were adapted with special equipment for electronic warfare operations and saw use in this capacity in Vietnam.

[45] On May 2, 1965, 18 USAF F-100s flew from Ramey Air Force Base in Puerto Rico to support Operation Power Pack flying 313 combat sorties before returning to Myrtle Beach on May 28.

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.

At Bitburg, they were assigned 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.

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 North Vietnamese Air Force[53] MiG-17, using cannon fire, while another fired AIM-9 Sidewinder missiles.

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.

[60] The Hun was also deployed as a two-seat F-100F model, which served as a "fast FAC" or Misty FAC in North 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.

[62] The four fighter wings with F-100s flew more combat sorties in Vietnam than over 15,000 North American P-51 Mustangs had flown during World War II.

No F-100 in Vietnam was lost to enemy fighters, but 186 were shot down by antiaircraft fire, seven were destroyed in Vietcong attacks on airbases, and 45 crashed in operational incidents.

[64] 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.