The major production version of the day-fighter Sabre was the F-86F. The F-86F Sabre was basically a more powerful version of the F-86E, being powered by the 5910 lb.st. J47-GE-27 engine in place of the 5200 lb.st. J47-GE-13. Work on the new aircraft began on July 31, 1950 as the NA-172, and was scheduled to begin production as the F-86F in October of 1950. A contract for 109 F-86Fs was approved on April 11, 1951, which was increased to 360 by June 30.
Plans were also made to manufacture the F-86F in the Columbus, Ohio factory that had been used by the Aeroplane Division of Curtiss-Wright during World War 2 to manufacture the SB2C Helldiver dive bomber. This plant had been built for Curtiss by the Navy during the war. After the war, Curtiss fell onto hard times, and was forced to undergo a major downsizing, eventually consolidating all of its aircraft operations at the Columbus factory. Curtiss-Wright was ultimately unsuccessful in securing any defense contracts, and was forced to close down its Aeronautical Division. All of the assets of the Aeroplane Division were sold to North American, but control of the Columbus factory reverted to the Navy. The Columbus factory had sat idle for several years. With the expansion in military orders caused by the Korean War, North American arranged to lease this factory for manufacture of the F-86F. This Columbus-built F-86F was designated NA-176 by NAA, and the project was formally initiated on September 29, 1950. The Columbus factory reopened in December 1950, and the initial Columbus contract, dated September 6, 1951 and approved March 17, 1952, was for 441 aircraft.
While Columbus was coming up to speed, the California plant began to produce some F-86Fs. Unfortunately, there were serious delays in the deliveries of the J47-GE-27 engines from General Electric, and the first 132 aircraft on the NA-172 contract had to be delivered with the less powerful -13 engine of the F-86E. Since this made them essentially F-86Es rather than F-86Fs, they were given the designation F-86E-10-NA. They were delivered between September 1951 and April 1952. They could be distinguished from earlier Es by the introduction of a new optically-flat armored windscreen which replaced the v-type windscreen of earlier F-86As and Es.
The J47-GE-27 engine finally became available in the early spring of 1952, and the first of 78 F-86F-1-NA aircraft (51-2850) took to the air on March 19, 1952. Other than the engine change, the F-1 was identical to the E-10. with the same weapons capabilities, wings and flight control systems. By June of 1952, they were in service with the 84th Squadron at Hamilton Field and with the 51st Wing in Korea. The F-86F was added to the 4th Wing in September.
With the same weight as the E-10 but with more engine thrust, the F offered significantly better performance over the E. The F's top speed rose to 688 mph at sea level and well over 600 mph at 35,000 feet. Service ceiling was up to 52,000 feet, and initial climb rate was now 9850 feet. The introduction of the F into combat in Korea went a long way to closing the high-altitude performance gap between the Sabre and the MiG-15. No longer could the MiGs zoom and climb through Sabre formations with impunity, and the Sabre pilots could now close on the MiGs at any altitude, even during a climb. The -27 engine also offered slightly better fuel economy, giving a combat radius of 430 miles with a pair of 120-US gallon drop tanks.
The F-86F-5-NA appeared in June of 1952. It differed in having underwing shackles capable of handling 200-gallon drop tanks instead of the earlier 120-gallon tanks. These increased the combat radius from 430 to 463 miles. 16 of these were built.
The F-86F-10-NA introduced a new gunsight. Most of the F-86As in Korea had used the Mark 18 optical gyrosight. The ranging control of this sight had to be operated manually, which was an awkward task for a pilot to perform under the stress of high-speed combat. Late F-86As and all Es had been fitted with an A-1CM radar ranger which relieved the pilot of the task of having to do the ranging task manually, but this equipment was rather complicated, was subject to frequent breakdowns, and was difficult to service and maintain. The F-86F-10-NA and later aircraft introduced the A-4 ranging system, which operated in a similar manner as the A-1CM, but was simpler to operate and easier to maintain. All other equipment on the F-86F-10 remained the same as on previous models.
The last 100 aircraft on the NA-172 contract were to have been F-86F-15-NAs with re-positioned control systems. Combat in Korea had shown that there were several vital areas in the F-86 where just one hit could result in severe damage and perhaps loss of the entire aircraft. All of these vital areas were identified and either repositioned, encased in armor plating, or given a backup system in case of failure. However, in April of 1952, additional delays in deliveries of General Electric J47-GE-27 engines forced another substitution of the earlier -13 engine in all but the first seven aircraft in this block. These 93 re-engined aircraft were then re-designated F-86E-15-NA and were issued to training units rather than to combat Wings. Six of the seven F-15s built are known to have been operational in Korea with the 4th FIG.
Columbus was rather slow in getting production going on their NA-176 contract, and the first Columbus-built F-86F aircraft (51-13070) did not fly until May of 1952. These aircraft were known as F-86F-20-NH (the Columbus-built Sabres having the suffix "NH", the California-built Sabres having the suffix "NA"). These aircraft were essentially duplicates of the Inglewood-built F-86F-15-NA, and could carry a pair of 200-gallon drop tanks and had armor protection fitted around the horizontal stabilizer control system. They had a different radio and cockpit arrangement than previous Sabres. Delivery of the 100 F-86F-20-NH aircraft was not completed until January of 1953. However,none of the F-86F-20s ever served in Korea.
The next version of the Sabre was known by the company as NA-191. The project began on October 26, 1951. This called for a fighter-bomber adaptation of the Sabre, capable of carrying two stores under each wing rather than just one. Earlier Sabres had been found to be deficient when called upon to assume the fighter-bomber role, primarily because of insufficient range and endurance when the drop tanks were replaced by bombs or rockets. The F-86A had a combat radius of only 50 miles when carrying underwing bombs, which was not a very useful distance! A contract was approved on August 5, 1952 for 907 NA-191 aircraft, all to be built in California. The same configuration was to be used on 341 NA-176 aircraft already on order from Columbus, plus 259 NA-193 aircraft added to the contract on October 17, 1952.
The first Sabre built to this fighter-bomber configuration was the F-86F-30-NA, which starting rolling off the production lines in California in October of 1952. All four hardpoints could handle either 120- or 200-US gallon drop tanks, but only the inner pair could carry ordnance, up to 1000 pounds for each pylon. This meant that an F-86F with the dual-store wing could carry a pair of 1000-pound bombs plus two 200-US gallon drop tanks on a typical mission. If the maximum fuel load of two 200-gallon and two 120-gallon drop tanks was carried, ferry range was 1600 miles and combat radius was 568 miles.
In January 1953, the Columbus-built version of the fighter-bomber Sabre, the F-86F-25-NH, had appeared.
In an attempt to improve the high-speed performance of the Sabre, a fixed wing leading edge was tested on three aircraft in August of 1952. These aircraft had the wing leading edge slats eliminated and their wing leading edges extended by six inches at the root and three inches at the tip. The wing area went from 287.9 to 302.3 square feet, and the angle of leading edge sweep increased slightly to 35.7 degrees. Airflow pattern changes over the wing required the addition of five-inch-high wing fences at 70 percent span. Since the leading edge extension occurred in front of the main wing spar, the extended leading edge could be used to accommodate some additional fuel, raising total internal fuel capacity from 435 to 505 US gallons.
This wing, soon to be known as the "6-3 wing", immediately demonstrated improved combat qualities. The "6-3" wing increased maximum speed from 688 to 695 mph at sea level and from 604 to 608 mph at 35,000 feet. In addition, there was a slight improvement in range. The most significant improvement was, however, in the maneuverability at high altitudes and at high Mach numbers. By delaying the onset of buffeting, the new wing gave the Sabre pilot the ability to fly closer to the maximum G-limit, enabling tighter turns at high altitudes. About 1.5 Gs were added to the maneuverability at 35,000 feet. Unfortunately, the improved high-speed performance came at the expense of losing the low-speed advantages of the slatted wing. Stalling speed went up from 128 to 144 mph, and the stall was now preceded by a yaw-and-roll effect. This resulted in a faster final landing approach speed and necessitated a longer landing roll.
Fifty "6-3" wing conversion kits were shipped to Korea in high secrecy in September of 1952 to convert F-86F aircraft already there to the new configuration. Enough kits were eventually supplied to convert all Korean-based F-86Fs and some F-86Es to this new configuration. The "6-3" wing was introduced as standard production line equipment starting with the 171st F-86F-25-NH (51-13341) and the 200th F-86F-30-NA (52-4505). No F-86F-25s were actually sent to Korea, with most of the combat aircraft used in Korean combat being early Fs from F-1 through F-15, plus large numbers of F-30s.
The "6-3" wing was an immediate success, quickly boosting Sabre victories in Korea. With the "6-3-wing" F-86F, the USAF now had a fighter which could match the maximum speed of the MiG at altitudes all the way up to the Sabre's service ceiling of 47,000 feet, could turn inside the MiG, and which had almost as great a rate of climb.
The third F-86F production batch was the NA-191, built in California under a contract approved on August 5, 1952. These were delivered as F-86F-30-NA (52-4305 through -5163) and as F-86F-35-NA (52-5164 through -5271). Deliveries began in October of 1952 and were completed by May of 1954. 967 were built.
157 NA-202 aircraft were built in California under the next contract. These included F-86F-35-NAs covering serials 53-1072 through 53-1228. The F-86F-35-NA had the capability of carrying a nuclear weapon. The 1200-pound Mk 12 "special store" (as the atomic bomb was euphemistically called) with a yield of up to 12 kT was carried under the port wing, while droptanks were attached under the starboard wing. The nuclear bomb was delivered by use of the Low Altitude Bombing System (LABS), in which the pilot approached the target at low altitude, pulled up to begin a loop, released the bomb near the top of the loop to throw the bomb away from the flight path, and then escaped the blast by climbing away with an Immelmann turn. The F-86F-35-NA was equipped with a computer for determining the exact instant of bomb release, along with a set of controls for arming and disarming the "special store" in flight. Conventional weapons that could be carried included a pair of 1000-pound or smaller bombs, two 750-pound napalm tanks, or eight 5-inch HVAR rockets. The F-35 was otherwise similar to other F-86Fs.
The F-86F served with the following USAF wings:
51-2850/2927 North American F-86F-1-NA Sabre c/n 172-133/200 51-2928/2943 North American F-86F-5-NA Sabre c/n 172-201/226. 51-12936/12969 North American F-86F-10-NA Sabre c/n 172-227/260. 51-12970/12976 North American F-86F-15-NA Sabre c/n 172-261/267. 51-13070/13169 North American F-86F-20-NH Sabre c/n 176-1/100. 51-13170/13510 North American F-86F-25-NH Sabre c/n 176-101/441. 52-4305/5163 North American F-86F-30-NA Sabre c/n 191-1/859. 52-5164/5271 North American F-86F-35-NA Sabre c/n 191-860/967. 52-5272/5530 North American F-86F-25-NH Sabre c/n 193-1/259. 53-1072/1228 North American F-86F-35-NA Sabre c/n 202-1/157