The F4D-2N Skyray was a 1953 proposal for an all-weather capable version of the F4D-1, which was at that time just beginning to enter production for the Navy. The aircraft was also to be aerodynamically refined in order to take full advantage of the increased thrust made available by the replacement of the Westinghouse J40 engine by the Pratt & Whitney J57 in production F4D-1s.
Two prototypes were ordered under the designation F4D-2N. Serials were BuNo 139208 and 139209. However, as engineering work progressed, the F4D-2N became progressively more and more different from the F4D-1, and the new design was redesignated F5D-1 and named Skylancer.
The F5D-1 retained the general wing planform of the F4D-1, but the wings were much thinner and the fuselage was 8 ft. longer. The wing was built with thicker reinforced skinning to correct problems which had been encountered with dents, dimples, depressions, and even rents in the wing skinning which were sometimes encountered during high-speed maneuvering with the F4D-1 version. The overall wingspan and wing area were, however, to be identical to those of the F4D-1 version. The internal fuel capacity was increased from 640 US gallons for the F4D-1 to 1333 US gallons. The fuselage of the F5D-1 adopted the Area Rule, being deliberately slimmed down in the region of the wing roots to improve the transonic flight characteristics. The air intakes were redesigned, and a new V-edged cockpit windshield and canopy replaced the rectangular, flat-topped units of the F4D-1. A taller fin and rudder was fitted. The landing gear track was widened by two and 1/2 feet to 12 feet 6 inches. Leading edge slat arrangement and rear control surfaces were markedly changed. The inboard trailing edge trimmers next to the exhaust pipe were now flush with the trailing edge, instead of extending sharply behind. The afterburner cooling intakes were enlarged and moved forward. The armament of four 20-mm cannon in the wings was retained, but the primary armament was to be a missile suite consisting of four Sidewinder or two Sparrow air-to-air guided missiles and/or a battery of spin-stabilized unguided 2-inch rockets. An advanced X-24A radar fire-control system was to have been used.
Nine service test machines (BuNos 142349/142357) and fifty-one production machines (BuNos 143393/143400 and 145159/145201) were ordered. The prototypes and the service test machines were to be powered by the Pratt & Whitney J57-P-8, rated at 10,200 lb.s.t. dry and 16,000 lb.s.t. with afterburning. Production machines were to have been powered by the J57-P-14 engine rated at 10,700 lb.s.t dry and 16,900 lb.s.t. with afterburning. However, it was planned that the Skylancer would ultimately be powered by the General Electric J79 turbojet.
The first F5D-1 (BuNo 139208) took off from Edwards AFB on its maiden flight on April 21, 1956, with test pilot Robert Rahn at the controls. It easily exceeded the speed of sound on its first flight.
The performance of the F5D-1 proved to be excellent. The new larger fuel tanks endowed the F5D-1 with twice the range of the F4D-1. A maximum speed of nearly 1000 mph could be attained at altitude. However, after two prototypes and two production examples had been constructed, the Navy decided to cancel its order for the Skylancer. The reason given was that the Navy had already decided to purchase the Vought F8U Crusader, and that they just really didn't need to have another fighter on their rolls with essentially the same performance characteristics. Politics might also have played a role, since Douglas was already heavily involved in the production of the A3D Skywarrior, the A4D Skyhawk, the F4D Skyray, and the AD Skyraider and that it would not be a good idea for Douglas to be given a virtual monopoly on Navy combat aircraft construction.
At the time of the cancellation of the Navy contract, two prototypes (139208 and 139209) and two service-test aircraft (142349 and 142350) had been constructed. Following the termination of the Navy Skylancer contract, these four planes participated in various military test programs throughout the late 1950s and early 1960s. 139209 and 142349 were grounded in 1961, but the other two were transferred to NASA's Dryden Flight Research Center at Edwards AFB. 139208 was renumbered as NASA 212 and was used in support of the US supersonic transport program. For a while, it was fitted with wings of modified ogee planform. It was transferred to the Ames Laboratory in 1963. While there, it was renumbered 708. 708 was retired in April of 1968. 142350 was renumbered as NASA 213 and was used for the simulation of abort procedures for the Boeing X-20A Dyna-Soar orbital spaceplane. Following the cancellation of the Dyna-Soar program, NASA 213 continued to fly in support of lifting-body projects and SST studies. It was finally retired in 1970. Both NASA F5D-1s were retired in 1970.
139208,139209 Douglas F5D-1 Skylancer (originally designated F4D-2N) 142349/142357 Douglas F5D-1 Skylancer --141351/142357 cancelled 143393/143400 Douglas F5D-1 Skylancer - all cancelled. 145159/145201 Douglas F5D-1 Skylancer - all cancelled.
Engine: One Pratt & Whitney J57-P-8 turbojet, 10,200 lb.s.t. dry and 16,000 lb.s.t. with afterburning. Maximum speed: 953 mph at 35,000 feet, 990 mph at 44,000 feet, 749 mph at sea level. Cruising speed 637 mph. Initial climb rate 20,790 feet per minute. An altitude of 30,000 feet could be attained in 7.9 minutes. Service ceiling 57,500 feet. Combat ceiling 49,200 feet. Landing speed 155 mph. Stalling speed 112.7 mph. Combat range 1335 miles. Weights: 17,444 pounds empty, 24,445 pounds combat, 25,000 pounds gross, 28,072 pounds maximum takeoff. Dimensions: wingspan 33 feet 6 inches, length 53 feet 9 3/4 inches, height 14 feet 10 inches, wing area 557 square feet. Internal fuel capacity was 1333 US gallons. Two 150-US gallon drop tanks could be carried underwing, bringing total maximum fuel capacity to 1633 US gallons. Armed with four 20-mm cannon in the wings.