May 25, 1953: George Welch Took North American’s YF-100A Super Sabre on its First Test Flight Published May 25, 2021 Air Force Flight Test Center EDWARDS AIR FORCE BASE, Calif -- George “Wheaties” Welch took North American’s YF-100A Super Sabre on its first test flight, reaching Mach 1.1 in the process. This was the first time an aircraft had reached supersonic speeds on its initial flight, and dramatically highlighted the aircraft as the nation’s first jet fighter with a supersonic capability in level flight. The F-100 was the first in the famed Century Series of fighters. 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 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. gallons and a pair of 200 U.S. gallons 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 (1,730 l) drop tanks. The 450s proved scarce and expensive and were often replaced by smaller 335 US gal (1,290 l) 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. The first F-100D (54–2121) 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.