The F-94A/B all-weather interceptors of the USAF were considered only as interim types which would fill in the gap for a couple of years until more advanced aircraft could be made available in quantity. Once their initial problems had been corrected, the F-94A/B proved to be quite reliable all-weather interceptors and were relatively easy to maintain in the field. However, the F-94A/B lacked sufficient range and climbing speed to make it a really good interceptor, and its armament did not pack sufficient punch to be considered really effective against bombers.
In July 1948, four months before receiving the contract for the first batch of F-94As, Lockheed issued a proposal to the USAF for a more advanced development of the F-94A concept. The project was given the company designation of L-188. In order to achieve higher Mach numbers, the L-188 featured a completely new wing with reduced thickness and greater dihedral. The speed brakes were revised and the fuel capacity was increased. The aircraft was to be provided with a drag 'chute, being the first USAF fighter to be so equipped. Since more power was clearly needed, a Pratt & Whitney J48 afterburning turbojet was to be fitted. This engine was a license-built version of the British-designed Rolls-Royce Tay. With afterburning, this engine offered 8750 pounds of thrust. The increased engine thrust required that the air intakes be revised and made larger. The rear fuselage had to be revised in order to accommodate this new engine. A more advanced Hughes E-5 fire control system with APG-40 radar was to be used. The machine gun armament of the F-94A was to be replaced by an all-rocket armament mounted in the fuselage nose.
The USAF was initially not all that interested in the Lockheed proposal, preferring to concentrate on the North American F-86D Sabre and the Northrop F-89 Scorpion. Nevertheless, the USAF thought enough of the proposal that they assigned it a designation of F-97. A new F-number was selected for the Lockheed proposal since it was almost a complete redesign of the F-94.
Undeterred by the USAF's initial lukewarm response to their L-188 proposal, Lockheed decided in 1949 to go ahead with the construction of a company-funded demonstrator aircraft that would combine the L-188 wing with a F-94A fuselage from which the military armament and fire control systems had been omitted. Since the J48 engine was not yet ready, the demonstrator was fitted with an imported non-afterburning Rolls-Royce Tay.
Bearing the civil registration N94C, the unarmed demonstrator flew for the first time on January 19, 1950, with test pilot Tony LeVier at the controls. It retained the original nose of the F-94A, and had non-standard teardrop-shaped centerline-mounted wingtip tanks. The USAF was sufficiently impressed that in February 1950 they purchased the unarmed L-188 demonstrator under the designation YF-97. The military serial number 50-955 replaced the original civil registration number. At the same time, the USAF ordered a fully militarized prototype YF-97 under the serial number 50-877. 180 production examples were ordered under the designation F-97A. The company designation for the F-97A was Model 880.
Initial trials with the L-188/YF-97 demonstrator turned up several problems which were corrected by progressive modifications. The wing root extension fillet of the original L-188 wing was removed in order to improve stall characteristics during landing approach. The original horizontal stabilizer of the F-94 was replaced by power-boosted swept surfaces to eliminate an annoying high-frequency vibration that took place at high Mach numbers. Dampers were added to correct aileron buzzing. Spoilers were added to improve roll control. The vertical fin was made larger in order to increase directional stability at high speeds. When the American-built Tay finally became available, the first YF-97 was re-engined with a J48-P-3 engine, rated at 6000 lb.s.t. dry and 8000 lb.s.t with afterburning.
On September 12, 1950, the YF-97 was redesignated YF-94C. Even though the YF-97 was almost a completely new aircraft, it was thought wise to pretend that the design was simply a "logical extension" of an existing aircraft. Political considerations often play an important role in the choice of aircraft designations.
The name Starfire was applied to the F-94C by publicists, following the tradition of naming Lockheed aircraft after celestial objects. The C-variant was the only variant in the F-94 series to carry this name.
The two YF-94Cs continued to be used for tests of the improved fire control system and the all-rocket armament. The all-rocket armament consisted of twenty-four 2.75-inch Folding-Fin Aircraft Rockets (FFAR) mounted in four groups surrounding the APG-40 radome in the nose. The rockets in each group were mounted inside a door which opened sideways on the ground for easy servicing and reloading. In front of each rocket group was a snap-action door which opened immediately before firing. The YF-94Cs were fitted with a revised fuel system accommodating 566 US gallons in wing and fuselage tanks, 500 gallons in center-mounted wingtip tanks, and 460 gallons in midwing drop tanks mounted on pylons at the wing center for a total fuel capacity of 1526 gallons. There were difficulties with the drag chute, with the automatic pilot, with the afterburner of the J48, and with aileron flutter. These problems were not fully resolved until after the first F-94C production aircraft had been delivered.
The first production F-94C was delivered in July of 1951. The production F-94C was powered by the Pratt & Whitney J48-P-5 engine rated at 6350 lb.s.t. dry and 8750 lb.s.t. with afterburning. Teething problems delayed the introduction of the F-94C into squadron service for almost two years. The F-94C finally entered service with the 437th Fighter Interceptor Squadron at Otis AFB in Massachusetts in June of 1953. The F-94C was the second type of fighter serving with the Air Defense Command (ADC) to use rockets as its sole armament, the North American F-86D Sabre being the first.
Initially, the F-94C suffered with some of the same teething troubles which had not been completely ironed out during the testing of the YF-94Cs. The E-5 fire control system had reliability problems. The cockpit seal tended to leak, causing electrical short-circuits. In addition, the jet engine tended to flame out when the nose rockets were fired. However, once these difficulties were cleared up, the F-94C became popular with its flight and maintenance crews. The rocket armament of the F-94C was considered to be more accurate than that of the F-86D Sabre, owing to the use of closed-breech launchers by the F-94C which increased the velocity of the rockets. However, the firing of the nose rockets violently shook the F-94C and blinded both crew members in exhaust smoke and fire.
387 F-94C aircraft were built and delivered between July of 1951 and May of 1954. In 1953, F-94Cs were delivered to the 29th, 48th, 66th, 332nd, 438th, and 497th Fighter Interceptor Squadrons. In 1954-55, F-94Cs went to the 27th, 39th, 61st, 64th, and 318th Squadrons. While the 319th FIS was not one of the squadrons to receive the F-94C directly from the factory, they did operate them from March 1956 until transition to the F-89J was completed in December 1957. Most of these squadrons served in the mainland United States, although the 39th did serve for a time in Japan.
In the course of its production and service life, the F-94C was progressively improved and upgraded, with new features continually being added in the field. New and improved ejector seats were provided, variable-position dive brakes were fitted, and a better drag chute was added. Beginning with the 100th F-94C leaving the production line, a twelve-rocket pod was mounted on each wing leading edge, doubling the armament of the Starfire. A frangible plastic nose covered the front of each pod, which shattered when the rockets were fired. These mid-wing rocket pods were retrofitted to earlier production machines. Owing to the crew blinding problem during rocket firing, the nose rockets were often omitted from F-94Cs in the field, the rocket armament being carried exclusively in the mid-wing pods. The nose radome initially had a rather blunt shape, but it was soon replaced by a more pointed radome which quickly became standard.
The F-94C Starfire became the first all-weather fighter to break the sound barrier, which happened by accident when test pilot Herman "Fish" Salmon put his F-94C into a dive from 45,000 feet, rolling over in afterburner.
A single F-94C was used to test the adoption of the Hughes GAR-1 Falcon missile as part of the basic armament of the Starfire. This aircraft was redesignated DF-94C. Although the Falcon missile was never made part of the Starfire's operational armament, these experiments provided data for later generations of ADC interceptors.
F-94C serial number 50-963 was experimentally fitted with an enlarged nose in which reconnaissance cameras were mounted in place of the interceptor's radar and rockets. This plane was redesignated EF-94C, the E standing for *Exempt*. E was used rather than the regular R for Reconnaissance because this aircraft was to be used strictly for research purposes.
The service life of the F-94C Starfire with the USAF was quite short, most of these aircraft being phased out and replaced by more advanced types after only a half-dozen years of service. The last F-94C left USAF service in February of 1959.
After leaving USAF service, F-94Cs were passed along to the Air National Guard. With the F-94Cs supplementing the earlier F-94A/B, the Starfire equipped twenty-one Fighter Interceptor Squadrons of the Air National Guard. The last F-94Cs were phased out of ANG service by the 179th Fighter Interceptor Squadron at the Duluth Municipal Airport, Minnesota during the summer of 1959.
50-877 Lockheed YF-97 Starfire -- later redesignated YF-94C 50-955 Lockheed YF-97 Starfire -- later redesignated YF-94C 50-956/1063 Lockheed F-94C-1-LO Starfire 51-5513/5698 Lockheed F-94C-1-LO Starfire 51-13511/13603 Lockheed F-94C-1-LO Starfire
Engine: One Pratt & Whitney J48-P-5 turbojet engine rated at 6350 lb.st. dry and 8750 lb.st. with afterburning. Dimensions: Wingspan 42 feet 5 inches with wingtip tanks, length 44 feet 6 inches, height 14 feet 11 inches, wing area 232.8 square feet. Weights: 12,708 pounds empty, 18,300 pounds loaded, 24,184 pound maximum. Performance: Maximum speed: 640 mph at sea level, 585 mph at 22,000 feet, 578 mph at 40,000 fee. Initial climb rate 7980 feet per minute. Service ceiling 51,400 feet. Normal range 805 miles, maximum range 1275 miles. Armament: Armed with twenty-four 2.75-inch Mighty Mouse FFARs in nose, plus twelve FFARs in each of two wing leading-edge pods.