History of the F-101 Voodoo
The McDonnell F-101 Voodoo twin-engined fighter was originally designed as a single-seat long range escort fighter to accompany the bombers of the Strategic Air Command if they were ever called upon to carry out their mission of nuclear strike against the Soviet Union. The Voodoo was destined never to serve in this particular role--it eventually emerged as a tactical reconnaissance aircraft, as a 2-seat long-range interceptor, and as a 2-seat nuclear strike aircraft.
It was the first production fighter capable of exceeding 1000 mph in level flight. Only the reconnaissance version ever saw combat, flying the fastest combat missions ever flown (with the exception of the SR-71) during flights over North Vietnam. However, it was not without its flaws--in all its versions, the Voodoo had a tendency to pitch up into a nose-high attitude without warning, a problem which was caused by the way in which air flowed over its wings and under its high tail.
The earlier McDonnell F-88 escort fighter had been unsuccessful in attracting any production orders, since the Air Force had assumed that the high performance of the B-47 and B-52 jet bombers would make escort fighters unnecessary in any future conflict. However, during the Korean War, the USAF had found that the Republic F-84 Thunderjet fighters escorting streams of B-29 bombers attacking targets along the Yalu River in North Korea were incapable of protecting their charges against attacks by the faster MiG 15. The more capable F-86 Sabre lacked the range and endurance to provide effective escort.
In order to meet this critical need for an effective long-range escort fighter, the USAF had originally planned on using the Republic F-84F Thunderstreak. However, the Strategic Air Command (SAC) also wanted a much longer-range escort fighter, one with sufficient range to accompany the Convair B-36 intercontinental bomber on its missions. In February 1951, the USAF issued a requirement for a fighter to fill this need.
Lockheed, North American, Northrop, Republic, and McDonnell all submitted proposals. Lockheed submitted both the F-90 and the F-94, North American resubmitted the F-93, and Northrop proposed an escort version of the F-89 Scorpion all-weather interceptor. Republic came up with three separate submissions, the F-91 Thunderceptor, the F-84F, plus another version of the F-84F powered by a turboprop engine. As its entry, McDonnell proposed a larger and more powerful version of its XF-88 penetration fighter prototype.
The McDonnell submission was judged the winner of the competition in May of 1951. In October of 1951, the USAF released fiscal year 1952 funds previously allocated to the F-84F and F-86F program to get McDonnell's proposal into production right away. A program similar to that used in the development of the F-100 Super Sabre was to be employed, one in which the ordinary prototype stage in development would be completely skipped and full production be instituted right from the start.
As the initial production aircraft rolled off the line, they would be tested and any changes deemed necessary would be introduced on later aircraft to come off the line. It was hoped that this strategy would get the new fighter into service as quickly as possible. This was a high-risk strategy, one which would give the Air Force a new plane in a hurry if everything went as planned, but one which would risk the high costs and long delays of a lot of in-service modifications should unexpected problems turn up during flight testing. However, considering that the McDonnell proposal was basically a scaled-up XF-88 rather than a truly "new" design, the risks were considered minimal.
On November 30, 1951, the new and improved F-88 was assigned the designation F-101. A Letter of Intent for the development of the McDonnell proposal was issued on January 3, 1952.
In December of 1951, the McDonnell team lead by Edward M. Flesh recommended that the F-101 be powered by a pair of afterburning Allison J71 turbojets. This nearly tripled the thrust of the pair of Westinghouse J34s that had powered the XF-88A, and was twice the thrust of the Westinghouse J46s proposed for the production F-88.
However, the Air Force thought that even this additional power was still not enough, and was in favor of using a pair of even more powerful Pratt & Whitney J57 afterburning engines. Unfortunately, the use of the more powerful J57 engines required some major design changes. Although the engines were to be placed in the same location as they were in the XF-88, the air intakes in the wing roots had to be redesigned and considerably enlarged to accommodate the increased air flow requirements. Since considerably more fuel had to be carried, the fuselage had to be lengthened and widened, increasing the internal fuel capacity more than threefold (2341 versus 734 US gallons). Provisions were made for the fitting of a pair of 450-gallon external tanks.
As compared to the XF-88, the all-movable tailplane was moved almost to the top of the vertical tail. The wing area was increased from 350 to 368 square feet, obtained by increasing the chord of the inboard half of each wing panel. The thickness of the wing was reduced, and the ailerons were moved further inboard.
The pressurized cockpit was enclosed by a clamshell-type cockpit canopy, and the pilot was provided with an ejector seat. Rear fuselage airbrakes and a braking parachute were fitted in order to enable the plane to land on shorter runways.
Provisions were made to accommodate both types of flight refuelling systems in use by the USAF. A retractable fuelling probe was to be mounted in front of the cockpit and a refuelling boom receptacle was to be installed on top of the center fuselage.
The F-101A was to be equipped with APS-54 radar and was to be armed with four 20-mm cannon as well as three Falcon air-to-air missiles and 12 unguided rockets. For ferrying purposes, the ammunition for the four 20-mm cannon could be replaced by a single 226-gallon auxiliary fuel tank.
The mockup was inspected in July of 1952. On May 28, 1953, the USAF issued an initial contract for 39 F-101As. No prototypes were specified, since the usual prototype stage was being skipped altogether.
The coming of peace in Korea in July of 1953 removed some of the sense of urgency connected with the F-101 program. By this time, the USAF had changed its mind and wanted McDonnell to redesign the aircraft so that it could not only carry out the originally-planned long-range escort mission but could also carry out nuclear strike missions. In May of 1954, the Air Force got cold feet about the wisdom of going directly into production with the F-101A and withdrew its authorization to proceed with quantity production and decided to wait until Category II flight tests could be carried out and all the required changes could be made. The target date for the completion of these tests was set for sometime in March of 1955.
F-101 production ended in 1961, with 805 built.
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