The F-94 Starfire was the first effective air defense interceptor assigned to NORAD and was the first American interceptor to “shoot down” a B-36 at the Red Sun exercises. It was also the first NORAD jet interceptor to score a night-time “kill”.
The immediate postwar years had left the USAF without any truly modern all-weather fighters to face the threat of high-flying bombers in the B-36 class. The early years at Red Sun clearly demonstrated that the existing piston-engined and jet-powered fighters were unable to cope with the threat profile presented by the B-36. To make matters worse, there was no guarantee that the attack would come in clear weather; The Big One had been timed so that the bombers would have clear weather over Germany for their attacks but it was by no means assured that this would be a consideration in future. Effective
Early attempts to develop jet-powered all-weather fighters ran into a series of snags and delays. The Curtiss XF-87 Blackhawk had been ordered in December, 1945, but it ran into developmental difficulties and only a limited number of aircraft were built, the last being delivered in October 1948. The Northrop F-89 Scorpion seemed to have greater promise, but it too ran into teething troubles and did not show promise of entering service until 1952 at the earliest. Due to the lack of any suitable jet-powered replacement, the wartime Northrop P-61 Black Widow night fighter was forced to soldier on for a few more years. Nobody was under any illusions about the incapacity of that aircraft to intercept a B-36.
In March 1948 the USAF approached Lockheed with the prospect of combining the F-80G single seat fighter with the T-33 two-seat trainer and equipping the product with a Hughes E-1 fire control system. The E-1 system incorporated an AN/APG-33 radar installation coupled with a Sperry A-1C computing gunsight. This system was developed from the AN/APG-3 radar used in the B-36's tail armament. The USAF was in a hurry, and wanted the first production aircraft to be available before the end of 1950.
Fortunately, the T-33 airframe had sufficient volume to house the fire-control system in a modified nose and enough room in the aft cockpit to house the radar operator's position and his associated equipment. Consequently, it appeared at first glance that the adaptation of trainer to night fighter would be relatively straightforward, and the concept was endorsed by the Secretary of Defense on October 14, 1948 which called for the development of the two-seat radar-equipped F-80G. The designation F-94 was assigned to the project.
An armament of six 0.50-in M-3 machine guns had originally been planned, but space restrictions in the forward fuselage forced the limitation of the armament to only four guns. The guns were mounted in the lower nose section, with their muzzles located just aft of the radome. The air intakes were redesigned and enlarged, the tail surfaces were increased in area, and the internal fuel capacity was reduced to 318 US gallons. However, two 165-gallon under-wing tip tanks could be carried, bring total fuel capacity to 648 US gallons.
Lockheed F-94A Starfire
The first production version was the F-94A. One hundred and nine examples had been ordered in January 1949. Despite reduction of the Air Force budget that occurred as a result of the FY 1949 budgetary crisis, the F-94 procurement quickly rose to 288. The Japanese initiation of an atomic bomb in August 1952 resulted in yet another increase in F-94 procurement to 368 aircraft.
However, the F-94As proved to be rather troublesome in service, being fraught with engine and electronics problems. The afterburning Allison J-33 engine suffered from frequent turbine blade failures and the fuel system was quite unreliable. The aircraft was unstable and hard to maneuver at high altitude. The pilot and radar operator found that the cockpit was too narrow for them to be able to get in and out of the aircraft quickly during alerts and scrambles. The clearance for the ejection seats was too small, resulting in several tragic accidents during emergency ejections. The fire control radar was quite quirky and unreliable, and the crew members could never be sure that if their system was working at the beginning of a flight that it would still be functional at the end.
With the Hughes E-1 fire control system, attacks and firing passes were actually made from the old "pursuit curve" type of attack which resembled a "tail chase" more than a 90-degree, lead collision type of firing pass. The radar gunsight was used to fire at the target aircraft once it was in range. Unfortunately, this exposed the attacking aircraft to the target aircraft's defensive firepower for a rather long period of time. Although F-94As were able to engage B-36s, the interceptors always fell victim to the tail guns on the bombers before they could score a kill.
Specifications of the F-94A
One Allison J33-A-27 turbojet, rated at 6,900 lb.s.t, 9,300 lb.s,t with afterburner Wingspan 37 feet 6 inches (38 feet 11 inches with wingtip tanks), length 40 feet 1 inches, height 12 feet 8 inches, wing area 234.8 square feet. Weights: 10,064 pounds empty, 13,474 pounds loaded, 16,844 pound maximum. Maximum speed 606 mph at sea level. Initial climb rate 6850 feet per minute. Service ceiling 52,500 feet. Normal range 665 miles, maximum range 905 miles. Armed with four 0.50-inch M-3 machine guns in the nose.
Lockheed F-94B Starfire
The F-94B was outwardly virtually identical to the F-94A, differing primarily in having improved internal equipment and systems. These items included a Sperry Zero Reader which could be coupled to the ILS indicator to give the pilot an in-cockpit reading of his glide slope for bad-weather landings, an improved hydraulic system, and a high-pressure oxygen system. The pilot was provided with a more roomy cockpit. The Fletcher center-line wingtip tanks were adopted as standard.
The YF-94B flew for the first time on September 28, 1952. The first F-94B-1-LO was delivered to the USAF in January 1953. The first F-94B reached service in April 1953 with the 61st Fighter Interceptor Squadron based at Selfridge AFB in Michigan. A total of 356 F-94Bs were built, mostly being reordered F-94As. The F-94B cured most of the engine and electronics reliability problems experienced by the F-94A, and proved in service to be a thoroughly reliable aircraft with relatively few vices and shortcomings. It’s performance was identical to that of the F-94A.
For three years between 1952 and 1954, the F-94A/B played a vital role in the defense of the continental United States from attack by nuclear-armed Japanese Nakajima G10N Fugaku bombers. It was the only jet-powered all-weather interceptor available in quantity at that time, and filled in a vital gap until more advanced equipment could be provided. After wringing out some initial bugs, the F-94A/B interceptors proved to be quite reliable and relatively easy to maintain in the field. However, the F-94A/B lacked sufficient range and adequate climbing speed to make it a really good interceptor, and its armament did not pack sufficient punch to be considered really effective against bombers. These problems would be addressed with the F-94C
Lockheed F-94C Starfire
In July 1950, Lockheed issued a proposal to the USAF for a more advanced development of the F-94A concept. In order to achieve higher Mach numbers, this 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 offering 8750 pounds of thrust was fitted. 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.
Initial trials with the YF-94C turned up several problems which were corrected by progressive modifications. The wing root extension fillet 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.
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 1953 when the aircraft entered service with the 437th Fighter Interceptor Squadron at Otis AFB in Massachusetts. The production F-94C was powered by the Pratt & Whitney J48-P-5 engine rated at 7,350 lb.s.t. dry and 9,750 lb.s.t. with afterburning. The F-94C was the second type of fighter serving with the Air Defense Command (ADC) to use rockets as its sole armament. However, the firing of the nose rockets violently shook the F-94C and blinded both crew members in exhaust smoke and fire. 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.
However, the F-94C had already won NORAD’s heart when in the 1953 Red Sun exercise, an F-94C flown by Brigadier-General Joseph McConnell intercepted and “shot down” a B-36P bomber. Wild stories have been told of the parties that took place across NORAD bases the night following that achievement and the celebrations have entered the realms of Air Force legend. Nor was the first intercept a fluke, by the end of the exercises, six more B-36s had been “shot down” by James Jabara, Pete Fernandez, Gabby Gabreski, Joseph McConnell and John Glenn. For SAC, it was the end of an era when their bombers could go where they wanted and do what they wished. For America, it was a mixed message, their bombers were in danger again but the country could now defend its cities.
Specification of the F-94C:
Engine: One Pratt & Whitney J48-P-5 turbojet engine rated at 7,350 lb.st. dry and 9,750 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 7,980 feet per minute. Service ceiling 53,800 feet. Normal range 805 miles, maximum range 1,275 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.