F-95A / F-86D and F86L "Interceptor"
The F-95A was an early designation for the F-86D. The prototype aircraft (S/N 50-577 & 50-578) were originally designated YF-86D, changed to YF-95A and finally redesignated YF-86D. Similarly, the production aircraft were designated F-95A, but changed to F-86D before production began.
F-86A- the F-86B and C were cancelled. In terms of time, a few F-86Ds came out of production between the F-86Es and F-86Fs. In actuality, the F-86D was virtually a new machine, retaining only the wing common to other F-86s. Its concept was unprecedented-an all-weather interceptor in which the second crew member (standard in all aircraft of this category) was supplanted by highly sophisticated electronic systems. The F-86D was also the first single-seat fighter in which the classic gun armament gave way to missiles.
Air intake repositioned under nose, which enclosed radar scanner; stronger wing (the wing slats of earlier F-86s were retained) and enlarged vertical tail surfaces to compensate for the additional fuselage area. Vortex generators (small tabs) fitted around the fuselage and tail-plane to ruffle the air flow around these areas and prevent air on the airframe surface from separating and causing drag. Hughes Aircraft Company's interception radar and associated fire-control system. These electronic devices could compute an air target's position, guide the fighter on to a beamattack converting to a collision course, lower a retractable tray of 24 rockets (2.75-inch Mighty Mouse," each with the power of a 75mm shell) and within 500 yards of the targets fire these automatically in salvos. More than half of the F-86Ds were powered by either the J47-GE-17 turbojet or by the -17B. Later productions received the higher-thrust J47-GE-33. All had afterburners. Engine control was an added feature of every F-86D. An electronic device to control fuel flow, it relieved the lone pilot of another responsibility.
Slippage of the F-89 program which prompted the decision to procure the F-94 also led to conversion of the F86 to interceptor configuration. Other proposals were considered, but selection of the F-86 as the basic airframe for elaboration was almost automatic. It was the best of the current jet fighters. Moreover, it would require little structural modification to accommodate the necessary nose radar and afterburner. Doubts of a single-seat interceptor's feasibility caused a slight delay, but production availability and tooling clinched the January selection. The F-95, as the one-man interceptor was then designated, went on the drawing boards in March 1949 at about the same time the F-86A entered operational service. In May North American began to modify two F-86A aircraft in line with the tentative interceptor specifications drawn during the intervening months.
The Secretary of the Air Force formally endorsed the Board of Senior Officers' recommendations 3 weeks after the Hughes Aircraft Company had been issued a contract for developing the new interceptor's fire-control system. The Secretary's approval was accompanied by the authorization to spend $7million for conversion of the F-86 to the interceptor configuration.
An engineering inspection of the experimental aircraft in August 1949 and the ensuing flight of September favorably impressed the Air Force. In the latter month, $79 million were made available for the purchase of 124 aircraft. The new interceptor, designated as the F-95 during the early stage of development, reverted to the F86D designation soon afterwards.
This order covered two prototypes and 122 production articles. Two months later, concurrent with the December decision that Soviet possession of the atomic bomb dictated prompt creation of a modern interceptor force, the F-86D was chosen to be the backbone of that force until the advanced "1954 Interceptor" became available. Another procurement order for 31 F-86Ds was issued in June 1950.
The YF-86D was powered by a J47-GE-17 turbojet. Its afterburner boosted its 5,000-1b static thrust to 6,650 pounds. The second prototype, fitted with a similar engine, was completed in March 1950.
North American used the second YF-86D to test a prototype of the Hughes 50-kw E-3 fire-control system (developed in advance of the more sophisticated 250-kw E-4). In October 1950, after numerous engineering changes, the E-3-equipped YF-86D moved to Hughes for further testing. The number and extent of the changes that ensued delayed until July 1951 delivery of the E-3 productions that eventually equipped some 35 F-86Ds. Meanwhile, fabrication of the E-4 prototype proceeded. When completed in November 1950, however, no F-86Ds were available to flight test it and a B25 had to be used. E-4 production systems reached North American in December 1951, after a 3-month delay. Still, the new E-4s did not properly perform. In addition, deficiencies in components shared by both the E-3 and E-4 fire-control systems continued uncorrected.
The Air Force earmarked for testing the first F86D deliveries because the F-86D had been committed to production before receipt (or even development) of its fire-control system and of the first electronic engine fuel control. Too, the Air Force could expect a number of problems simply due to the aircraft's overall complexity. Nonetheless, there was still hope in mid-1951 that the F-86D would reach the operational units by the spring of 1952.
In March 1951, 341 F-86Ds were on order. Two months later this total jumped to 979 aircraft. The growth to 2,500 planes by January 1953 underlined the F-86D program's urgency and scope. Yet, by that time, the Air Force had accepted less than 90 F-86Ds.
Delay of the F-86D program stemmed from two principal problems. First, the E4 fire-control system had deficiencies not detected until service tests were run, and the development period was unusually long (in 1952 alone, Hughes had to make 150 changes to the system). Second, the General Electric J47-GE-17 turbojet engine-chiefly its electronic fuel control system was far from ready. By early 1952, GE had fallen 18 months behind in engine deliveries and the J47-GE-17 did not pass its 150-hour qualification test until the latter part of 1952. Meanwhile, after an initial production slippage, airframes had begun piling up around the North American plant for lack of engines.
The Air Force received more F-86Ds in March 1952. Although no longer considered test aircraft, they (and a few more . delivered during the summer) did not fully satisfy the Air Force requirements. They lacked the Lear F-5 autopilot and the E-4 fire-control system. The former had failed its qualifying environment tests and the latter was not reliable enough for inclusion in production aircraft until August 1952. The Air Force allocated these early F86Ds to the Air Training Command.
Nearly 2 years behind schedule and 6 months past the revised date of November 1952. However, several ADC squadrons were quickly equipped and later buildup was rapid. The Air Defense Command had 600 F-86Ds by the end of 1953. In June 1955, 1,026 (or 73 percent) of the command's 1,405 tactical aircraft were F86Ds-the remainder were F-94Cs and F-89Ds.
Operational Problems ~ 1953-1954 Engine malfunctions dogged the F.-86Ds almost as soon as they became operational. When engine fires and explosions destroyed 1.3 aircraft, the entire F-86D fleet was grounded in December 1953. Most of the aircraft were back flying by the end of February 1954, after hastily formed teams of North American and General Electric technicians corrected the faulty fuel system. This was merely a stop-gap measure, however. Soon afterward, 19 more accidents occurred in 1 month, this time because of poor maintenance of the complex weapon system (a situation which had been predicted in early service tests of the F-86Dsingle-man concept). Meanwhile, despite other deficiencies, production rates increased significantly.
The Air Force knew the F-86D needed improvement. Back in January 1953, 40 mandatory engineering fixes had been identified along with required changes to bring the aircraft to peak capability. Nevertheless, the F-86D was still a better interceptor than the other two in service and its immediate availability was crucial. The Air Force deemed the F-86D "almost as important as the B47" and the rash of operational troubles in 1953 only hastened the aircraft improvement. Project Pullout would embody in all F-86Ds the fixes accumulated piecemeal thus far, as well as the more important modifications previously intended for the future.
Cold War pressure forced the Air Force to ship 52 F-86Ds to the Far East Air Force in the fall of 1953. These aircraft were known to be deficient. Of those sent to Korea (where only short landing strips were available), few ever flew. The contingent soon returned to the United States and went through the pullout modifications as part of FEAF's retrofit program. FEAF received in exchange modified or new P-86D productions. In 1959, 6 years after the first F-86D oversea deployment, two squadrons of F-86D interceptors (the 431st and 437th FIS), recently placed under the Strategic Air Command's control, stood on alert at Torrejon and Zaragoza Air Bases in Spain.
The pullout modifications, started in March 1954, were completed at a cost of some $100 million after a purposeful year-and-a-half schedule. It was important that the 1,128 aircraft involved (plus 53 spare aft fuselages) be modified as rapidly as possible. Still the Air Force could not chance endangering the nation's air defenses by pulling too many F-86Ds out of service at once. Each aircraft underwent close to 300 modifications, some involving major changes. These included: correction of the autopilot and firecontrol systems (accomplished by Lear and Hughes, respectively); installation of a radar tape system to record radar-scope data during flight; modification of the stabilizer control system; installation of a 16 foot, ring-slot type drag chute in the aircraft tail (expected to reduce landing roll as much as 40 percent); and replacement of the J47-GE-17 engine by the much improved -17B (predecessor of the J47-GE-33 which powered the last 987 F-86D productions). The Sacramento Air Materiel Area (SMAMA) at McClellan AFB, Calif., was charged with the entire pullout program. A large part of the work, however, was done under contract by the North American plants at Inglewood and at Fresno, Calif. Upon completion, the Air Force had a modern, all-weather interceptor, but problems still loomed ahead.
An F-86D squadron operational suitability test (OST), Project Lock-On, was conducted at George AFB, Calif., during February 1954-1 month before the beginning of Pullout. As anticipated Lock-On concluded that an ADC F-86D squadron could not perform its assigned mission until elimination of the aircraft malfunctions by the .forthcoming Pullout modifications. The Lock-On findings also confirmed ineffectiveness of the F-86D squadron's air-ground control team and known requirements for additional ground-support equipment, better maintenance personnel, and increased pilot training. Other tests disclosed that the F-86D's 2.75-inch folding-fin serial rockets were marginal in accuracy and effectiveness. Use of the Falcon missile (given up in 1952) was reconsidered, but again discarded because it would require refit ting the aircraft with the E--9 fire-control system. In early 1955 the Air Force also decided not to arm the F-436D with Ding Dong rockets, since the Air Defense Command's two-missile load requirement would drastically reduce the aircraft's radius of action.
The new J47-GE-33 fitted in the last 987 F-86Ds was much more powerful than the -17 engine of the earlier productions. The -33's static thrust with afterburner reached 7,650 pounds, a 1,000-1b increase over the -17, under similar conditions. The -33 had better cooling and afterburner ignition. It also featured several detail changes which eliminated the flaws that had led to replacement of the original -17 by the improved -17B. Yet, 65 of 209 accidents in the 15 months preceding mid-1856 were attributed -to the aircraft's -17B or -,33 engine. Of these 65 accidents, 22 were caused by engine fuel control malfunctions; 17 by defective engine parts, and the remaining. 26 (most occurring in early 1955) by turbine wheel failures in-the -17B power plants.lb In mid-195b the Air Force thought of * retrofitting all -17B engines (as well as the -1? which still powered several F-86Ds) with a redesigned "locking strip" model. This project's $20 million price tag shaped the ultimate decision of installing the redesigned turbine wheels only upon attrition. Insistence on accurate records of turbine wheel use would assure adequate protection.
In addition to engine problems and despite the remarkable overall achievement of Pullout, the F-86D needed further improvement. Its E-4 fire-control system remained unreliable and difficult to maintain. Various engineering changes could still be made to increase reliability, ease maintenance and, perhaps, raise the F86D's kill capability. However, the gain would not justify the cost. The Air Force, therefore, reconsidered providing the aircraft with additional armament. Two F-86Ds were prototyped, one with GAR,-1B Falcons, the other with infrared homing Sidewinder missiles. Budgetary limitations, nevertheless, ended the two projects in September 1957. The Air Force concurrently altered several plans. It decided to phaseout the F-86D as soon as possible and its converted version, the F-86L, tentatively by mid-1960.
End of Production September 1953
The F-86D was phased out of the Air Defense Command in April 1958. By mid-1959 two ANG squadrons (the 122 and 182 FIS) were fully equipped. However, the Guard's F-S6Ds were also quickly supplanted by F-86Ls (converted F-86Ds). By June 1961 the F86D no longer appeared on either the USAF or ANG rolls. Yet, the interceptor's operational life was not over. Of 300 F-86Ds reaching MAP countries, Japan received 106. Milestones
19 November 1952
The Air Force set world speed record of 699.92 mph over a 3kilometer course at Salton Sea, Calif. This record was to stand unbeaten until raised by another F46D.
16 July 1953
New world speed record of 715.74 mph established with F-86D over the Salton Sea 3-kilometer course.
2 September 1953
The Air Force set world speed record of 690.186 mph over, 100kilometer closed course at Vandalia, Ohio. On the same day, with another F-86D, the Air Force also set speed record of 707.876 mph over the Vandalia 15-kilometer straight course.
The F-86L, converted from the F-86D had many new features including, electronic equipment (AN/ARR-39 Data Link receiver, AN/ARG 34 command radio, AN/APX 2b identification radar, and new glide slope receiver) that permitted the aircraft to operate in conjunction with the SAGE ground environment and with the GPA-37, electronic heart of an advanced system of ground control interception which immediately preceded SAGE. Also, slat-equipped, extended-wing leading edges (similar to those of the F-,86F and F86H), which brought the aircraft's empty weight to 13,822 pounds (a 1,352-1b increase), but improved maneuverability at high altitudes.
Conversion of the F-86D to the F-86L was more a matter of modification than development, but delays arose. In January 1955 deficiencies were noted in the control surface tie-in (CSTI) equipment, the signal data recorder (NADAR) slipped, a coupler for the data link (AN/ARRr39) was needed, and modification of the E-4 fire-control system to accept inputs from the coupler remained to be done. Despite such uncertainties, the Air Force hoped to have a completed electronic prototype by December 1955.
The Air Force conducted a development engineering inspection of the F-86D cockpit mockup readied for the new electronic configuration. The inspection, held at the North American Fresno plant on 1 May 1955, was a success. The Air Force found the new cockpit satisfactory and only minor changes were forecast. The ensuing lack of installation data, lack of flight test data, and nonavailability of the equipment to be installed, torpedoed North American's optimism that the electronic modification - program might well start earlier than planned.
In the fall of 1955 when the modification program was officially announced, the Air Force intended to modify 1,240 ADC F-86D aircraft, but the number actually converted amounted to about half that number.
Conversion of the F86D to the L configuration was accomplished by the Sacramento Air Materiel Area and North American's Inglewood and Fresno plants. Known as Project Follow-On, the modification program did not begin until May 1956. Once started, however, the Follow-On outputs accelerated rapidly.
The first to receive the new aircraft was the 49th Fighter Interceptor Squadron at Hanscom Field, Mass. By the end of 1957, only 18 months after the beginning of Follow-On, ADC had received 576 F-86L aircraft.
The F-86L, being a converted F-BFD, carried that aircraft's price tag of $343,839.00. This amount did not reflect the significant cost of the Follow On modifications.
With the advent of more modern interceptors of the F-101B and F-106 types, the need for the F-86L declined. Two ANG squadrons (the 111th and 159th) already had flown the F-86L by mid-1959, and by the end of that year the ADC inventory of F-86Ls was down to 133. The last F-86L left the Air Defense Command in June 1960, but the interceptor remained a valuable Guard asset until mid-1965.
|Join the GlobalSecurity.org mailing list|