On 12 December 1952, the USAF issued a General Operational Requirement for a lightweight air-superiority fighter to replace the North American F-100 in the Tactical Air Command beginning in 1956. Lockheed, Republic, North American and Northrop submitted proposals. Lockheed’s proposal was selected in January 1953. On 12 March 1953 a letter contract for two prototypes was issued under Weapon System 303A (WS-303A). The designation XF-104 was assigned, the prototypes being numbered 53-7786 and 53-7787. Lockheed assigned to the aircraft the company designation of Model 083-92-01.
The XF-104 mockup was inspected on 30 April 1953.
Construction of the first prototype XF-104, designated 0001 by Lockheed, began that summer at Lockheed’s Burbank, California facility. It was rolled out on 23 February 1954 and was ferried by truck to Edwards, departing on 24 February and arriving there on 25 February.
Lockheed test pilot Tony Levier began taxi trials on 27 February, making seven runs. He made four more taxi runs on the following day, including a short hop of about five feet off the ground.
Levier made the first official flight on 4 March 1954. During that low-speed flight, the landing gear could not be retracted, but was otherwise uneventful. After some adjustments LeVier took off again on Flight 2, but the landing gear still could not be retracted. Inspection revealed that the problem was due to low pressure in the hydraulic system, and was easily corrected. Bad weather kept the XF-104 grounded until 26 March when Levier made Flights 3 and 4. The landing gear retracted normally.
Flights 5 – 14 were made in April. Levier made Flight 15 on 26 April.
Flights 15 – 21 were made in May.
Flight 22 took place on 2 June, and Flight 25 took place on 10 June 1954.
The XF-104 began its flying carrier powered by the non-afterburning J65-B-3 turbojet. With this engine, it could not exceed the speed of sound in level flight but could easily exceed Mach 1 during a slight descent, and the transition to supersonic speed was quite smooth.
In July 1954, after the completion of Phase I testing, the J65-B-3 non-afterburning engine was replaced by the long-awaited afterburning J65-W-7 turbojet, rated at 7,800 lb thrust dry and 10,200 lb with afterburner. In that same month, 17 more service test aircraft were ordered, under the designation YF-104A. They were also to be powered by the J65-W-7. Phase II flight-testing began on 24 September 1954. Flight 30 took place on 8 October. Meanwhile construction of the second prototype had been proceeding.
Construction of the second prototype (53-7787), intended as armament test bed, began in the autumn of 1953, but work on this aircraft proceeded at a slower pace in case revisions were needed. The air intakes of the two XF-104s were of fixed geometry without presence of half-cones, since the J65-powered aircraft was incapable of Mach-2 performance. The air intakes were similar to those of the F-94C, being mounted slightly proud of the fuselage, with an inner splitter plate for the boundary layer bleed.
The XF-104’s original yaw damper was ineffective, allowing the nose to wander left and right. This problem was corrected by revising the rudder-centering device. With the afterburning engine installed, the performance of the XF-104 was markedly improved. Maximum level speed was Mach 1.49 at 41,000 feet, and an altitude of 55,000 feet could be attained in a zoom climb. Mach 1.6 could be attained in a dive.
The second prototype (53-7787) flew on 5 October 1954. It was fitted with the afterburning J65 from the start. Since it was to be the armament test bed, it was fitted with the 20-mm Vulcan cannon and was equipped with an AN/ASG-14T-1 fire control system. Initial aerial firing tests with the Vulcan cannon were successful, but on 17 December, there was an explosion during a firing burst, and the J65 engine started to run rough. Test pilot Tony LeVier immediately shut down his engine and glided back to make a successful dead-stick landing at Rogers Dry Lake. An investigation later showed that one of the 20-mm cannon rounds had exploded in the breech, blowing the bolt out the rear of the gun and into the forward fuselage fuel cell. Jet fuel gushed into the gun bay, and leaked out of the gun bay door joints and into the left engine air intake. The engine immediately flooded with fuel, choking it to death. Tony LeVier was lucky to be alive.
XF-104 number one achieved a top speed of Mach 1.79 at 60,000 feet on 15 March 1955. Lockheed test pilot J. Ray Goudey was at the controls. This was the highest speed achieved by either of the XF-104 prototypes.
The second prototype (53-7787) was lost on 14 April 1955 when test pilot Herman R. “Fish” Salmon was forced to eject during gun-firing trials at 50,000 feet. The gun malfunctioned during a test firing, and severe vibrations began to build up which knocked loose the ejection hatch on the belly of the plane. Cabin pressure was immediately lost, and Salmon’s pressure suit pumped up and covered his face so that he could not see. Recalling Tony LeVier’s harrowing experience with the exploding cannon shell the previous December, Salmon believed that the same thing had happened to him and that he had no option but to eject. This he did. He later found out that he could have saved 53-7787 by simply bringing it down to a lower altitude and waiting for his pressure suit to deflate.
With the loss of the armament test bed, Lockheed engineers were forced to find an alternative. Armament trials were continued on a modified Lockheed F-94C
XF-104 number 1 was accepted by the USAF in November of 1955. It was lost in a crash on 11 July 1957, when it developed an uncontrollable tail
flutter while flying chase for F-104A flight tests. The entire tail group was ripped from the airframe, and Lockheed test pilot Bill Park was forced to eject.
Consequently, no XF-104 prototype survives today.
© Henry Matthews 2012