The F-100A (company designation NA-192) was the first production version of the Super Sabre. The first F-100A (52-5756) was completed on September 25, 1953, and made its first flight on October 29, George Welch again being at the controls. This was only two weeks after the maiden flight of the second YF-100A prototype, indicative of the speed with which the Super Sabre program was being rushed along.
The F-100A was similar in most respects to the YF-100A, but had a shorter and more stubby vertical tail with increased chord. There was a fuel vent tube mounted on the fin's trailing edge at the midpoint. There was a small rudder fitted to the trailing edge of the fin below the vent tube.
The mission of the F-100A was seen as that of daylight air superiority, and the aircraft was pictured as the natural replacement of the F-86A/E/F Sabre of Korean War fame. The armament of the F-100A consisted of four 20-mm Pontiac M-39 cannon installed in the lower fuselage below the cockpit and carrying 200 rounds per gun. The M-39 had been tested in Korea on modified F-86Fs as the T-160, and fired 1500 rounds per minute at a muzzle velocity of 3300 feet per second.
At the end of November of 1953, the first three F-100As were delivered to George AFB to re-equip the 436th Fighter Day Squadron of the 479th Fighter Day Group of the TAC. This Group became operational with the F-100A on September 29, 1954.
During late 1953, slippages in the Republic F-84F Thunderstreak program caused the Tactical Air Command (TAC) to recommend that a version of the Super Sabre be developed with a secondary fighter-bomber capability. On December 31, 1953 the USAF directed that the last 70 F-100As on the order be modified as fighter-bombers and redesignated F-100C. The fourth production F-100A (52-5759) was chosen for modification as the prototype for the F-100C. The wingtips were extended twelve inches on either side, improving the roll characteristics and decreasing stalling speed. These wingtip extensions were considered sufficiently advantageous that they were incorporated into the F-100A production line beginning with the 101st example.
The first F-100As had been delivered with a short vertical tail. In service, USAF pilots reported stability and control problems with their F-100As, and their suspicion was that the vertical tail was not large enough to maintain adequate directional stability. This problem was especially severe when the underwing drop tanks were being carried. Consequently, most of these early F-100As were never flown to the limits of their performance envelopes.
The 11th F-100A introduced a retractable tail skid to prevent accidental damage to the rear fuselage underbelly during landings at high angles of attack.
The 24th F-100A introduced a yaw damper system. Provisions for a pitch damper were installed in the 154th and subsequent aircraft.
The F-100A had been rushed into service with unseeming haste, often over the objections of Air Force flight crews who found that the Super Sabre had some serious problems that were not being adequately addressed. Disaster struck on October 12, 1954. On that day, veteran test pilot George Welch was carrying out a maximum performance test dive followed by a high-G pullout with the ninth production F-100A (52-5764) when his aircraft disintegrated in midair. Welch was able to eject, but his injuries proved to be fatal since his airplane had broken at the cockpit area and had sent chunks of metal tearing into his body. On November 8, visiting RAF officer Geoffrey D. Stephenson was killed at Elgin AFB when his F-100A went out of control and crashed. On November 9, Major Frank N. Emory's F-100A (52-5771) went out of control and crashed during a practice gunnery mission over Nevada. Fortunately, Major Emory was able to eject safely. On November 10, the USAF grounded the entire F-100A fleet, which by this time numbered about seventy aircraft. A further 108 Super Sabres had been completed and were awaiting delivery at the factory.
After an exhaustive investigation, the source of the F-100A's stability problems was traced to its new shorter tail, which USAF test pilots had suspected all along. A decision was made to switch back to the original taller tail of the YF-100A. 27 percent more vertical tail area was added, which served to delay the onset of instability to speeds above Mach 1.4, which were outside the F-100A's performance envelope. The aspect ratio of the vertical tail was also increased. With these changes, the height of the modified F-100A increased to 15.34 feet. The wingtip extensions planned for the F-100C were adopted as standard for the F-100A, increasing the wingspan from 36.78 feet to 38.78 feet and the wing area from 376 square feet to 385.21 square feet. The artificial feel systems for the aileron and stabilizer powered controls were modified.
These changes seemed to do the job, and the existing F-100As were retrofitted with the changes. The first aircraft to complete the modification program was the 34th Super Sabre, and the first batch of 11 modified aircraft was delivered to NAA Engineering Flight Test. Because of the rapid rate at which production had been built up, it was not until the 184th airframe that these modifications could be introduced on the assembly line. Earlier aircraft (68 accepted and 112 completed) were retrofitted in hangar areas. Deliveries of the modified F-100A began from the Los Angeles factory in the spring of 1954. The grounding order on the F-100A was finally lifted early in February of 1955.
Initial operational capability with the new and improved F-100A was achieved in September of 1955 by the 479th Fighter Day Wing at George AFB. Late in 1955, pilots from the USAF Air Proving Ground Command at Elgin AFB in Florida participated in *Project Hot Rod* to evaluate the suitability of the F-100A for operational service. Their conclusions were similar to those of earlier evaluations--the performance was good but there were still some major operational deficiencies which prevented the F-100A from being a really good day fighter. Consequently, the F-100A was never very popular with its flight crews.
F-100As from number 167 onward had the J57-P-39 engine, which had the same thrust as the P-7.
The ejector seat of the F-100A received a rather spectacular test of its effectiveness on February 26, 1955. On that day, company test pilot George F. Smith was doing a low-altitude speed run in F-100A serial number 53-1659 when his plane suffered a hydraulic lock which resulted in an uncontrollable dive. He was forced to eject at Mach 1.05 and was severely injured, but recovered to fly again. I think that Smith was the first pilot to eject at supersonic speed and survive.
The last F-100A was delivered to the USAF in July of 1955. A total of 203 F-100As were built.
Since the F-100A was not considered as a truly effective air superiority fighter, the service life of the type with the USAF was rather brief, most aircraft being phased out of the active USAF inventory beginning in 1958. They were then transferred to the Air National Guard or placed in storage at Nellis AFB.
In mid-1959, fifteen of these stored F-100As were transferred to the Chinese Nationalist Air Force on Taiwan. In 1960, 65 more F-100As were sent to China.
The first Air National Guard unit to receive the F-100A was the 188th TFS of the New Mexico ANG, which received these planes in April of 1958. In 1960, the ANG reached its peak inventory of 70 F-100As. During the Berlin crisis of 1961, numerous Air National Guard and Air Force Reserve units were mobilized and called to active duty. This had the effect of returning some of these ex-USAF F-100As to active service.
In spite of their deficiencies, some F-100As which had been operated by these activated ANG units were retained by the USAF even after the ANG personnel were released from active duty in early 1962 following the end of the Berlin crisis. Most of the F-100As retained by the USAF were used for aircrew training and were not considered as being combat-capable aircraft.
Thirty-eight of these reactivated F-100As were transferred to Nationalist China. A total of 118 F-100As were ultimately transferred to the Chinese Nationalist Air Force, which was more than 58 percent of the total F-100A production. Many of these F-100As were upgraded with the vertical tail of the later F-100D before being sent to China.
The F-100A had an abominable safety record, even after the modifications which had corrected the stability problems with the original short vertical tail. About 50 F-100A were lost in accidents while in service, which was about 25 percent of the total F-100A production. One of the more serious problems was the notorious "Sabre Dance", which an F-100 pilot could find himself in if he did not properly fly the aircraft while in the landing pattern. This was a sudden pitchup, yaw, and loss of roll control, usually resulting in a crash. The last F-100A finally left USAF service in early 1970. The ANG had lost its last F-100A to attrition in 1967.
The NACA received an early F-100A (52-5778) which it used to perform stability and control tests. NACA test pilot Scott Crossfield flew the F-100A during the late fall of 1954 to determine the flight boundaries where inertial coupling could occur.
Serials of the F-100A:
52-5756/5765 North American F-100A-1-NA Super Sabre 52-5766/5778 North American F-100A-5-NA Super Sabre 53-1529/1568 North American F-100A-10-NA Super Sabre 53-1569/1608 North American F-100A-15-NA Super Sabre 53-1609/1708 North American F-100A-20-NA Super Sabre
Specificiations of the F-100A:
Engine: One Pratt & Whitney J57-P-7/39 turbojet, 9700 lb.st. dry and 14,800 lb.st. with afterburning. Dimensions: Wingspan 38 feet 9 inches, length 47 feet 1 1/4 inches, height 15 feet 8 inches, wing area 385 square feet. Performance: Maximum speed 760 mph at sea level, 852 mph at 35,000 feet. Initial climb rate 23,800 feet/minute. Service ceiling 44,900 feet, combat ceiling 51,000 feet. Normal range 358 miles, maximum range 1294 miles. Fuel capacity 1294 US gallons. Weights: 18,185 pounds empty, 24,996 pounds gross. Armament: Four 20-mm Pontaic M-39 cannon with 200 rpg. In addition, two underwing stations were provided which could accommodate bombs as large as 1000 pounds in weight.
Sources:
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North American F-100 Super Sabre, David A. Anderton, Osprey, 1987
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The North American F-100 Super Sabre, Ray Wagner, Aircraft in Profile,
1965.
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United States Military Aircraft Since 1909, Gordon Swanborough and
Peter M. Bowers, Smithsonian, 1989.
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The American Fighter, Enzo Angelucci and Peter Bowers, Orion, 1987.
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Fighters of the United States Air Force, Robert F. Dorr and
David Donald, Temple Press Aerospace, 1990.
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American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday,
1982.
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Post-World War II Fighters, 1945-1973, Marcelle Size Knaack,
Office of Air Force History, 1986.
- E-mail from Charles Friend on the "Sabre Dance".
