The history of the F3D Skyknight can be traced back to late 1945, when Navy representatives began discussions with aircraft manufacturers about requirements for a jet-powered carrier-based radar-equipped night fighter capable of detecting enemy aircraft at distances of up to 125 miles. The state of radar technology at the time was such that an additional crewman would be needed to operate such a powerful radar set. Maximum speed was to be at least 500 mph and service ceiling was to be 40,000 feet.
Curtiss, Douglas, Fleetwings, Grumman, and Douglas were invited to submit proposals. The Douglas team was led by Ed Heinemann. The preliminary design work began in October of 1945 and the mockup was inspected in April of 1946. Heinemann's team came up with a mid-wing design powered by two 3000-lb.st Westinghouse J34 axial-flow turbojets installed in semi-external nacelles housed underneath the fuselage center section. A Westinghouse APQ-35 search and target acquisition radar was to be carried in the nose. The large size of this radar installation required that a wide fuselage be designed to accommodate it, and the team adopted a side-by-side seating arrangement for the two crew members. The fuselage was fairly conventional, with a tail section similar in general configuration to that of the Skystreak and Skyraider. Large sideways-opening speed brakes were installed on the sides of the rear fuselage. A conventional tricycle landing gear was chosen, with the main landing gear members retracting outward into receptacles in the inner wing panels. An auxiliary tailwheel was added to the rear ventral fuselage as a precaution to prevent airframe damage during nose-high landings. A separate carrier arrester hook was fitted behind the auxiliary tailwheel. The wings folded upward at mid-span for stowage aboard carriers. Armament consisted of four 20-mm cannon mounted in the lower part of the nose.
Since the aircraft's seating arrangement would not permit the use of the ejector seats that were at that time available, the aircraft was provided with a tunnel escape system. This consisted of a ventral exit tunnel behind the cockpit, through which the two crew members could slide one at a time, feet first and facing aft. The tunnel exited the aircraft through a hatch located underneath the belly between the engines. The escape sequence was initiated by pulling a lever which blew off the aft portion of the belly hatch door, the forward part of the hatch door hinging forward to act as a windbreak. The crew would then pivot in their seats, grasp a vaulting bar attached to the wall behind their seats, kick open the cockpit exit door behind their seats, and then jump feet first into the tunnel and fall out the bottom of the plane.
The Navy judged the Douglas proposal as the best of the designs submitted, and awarded Douglas a contract for three prototypes under the designation XF3D-1 on April 3, 1946. Serials were 121457/121459. The name Skyknight was chosen. Eight days later, the competing Grumman proposal for a four-engined night fighter was awarded a contract for two prototypes under the designation XF9F-1, as insurance in case the Douglas design ran into difficulty. In the event, the Grumman contract was rewritten so that the four-engined XF9F-1 night fighter metamorphosed into the single-engined XF9F-2 day fighter, the progenitor of the famous Panther/Cougar line of naval carrier-based fighters.
The first Skyknight prototype was ready for its first flight in early 1948. The XF3D-1 was fitted with a pair of Westinghouse J34-WE-22 axial-flow turbojets, rated at 3000 lb.s.t. each. The XF3D-1 prototypes were initially fitted with SCR-720 radar sets, since the APQ-35 radar system was not yet available. The first of three XF3D-1s (BuNo 121457) took off on its maiden flight on March 23, 1948, test pilot Russ Thaw being at the controls. The second flew on June 6, 1948, followed by the third on October 7, 1948. In October 1948, tests of the XF3D-1 at Patuxent River, Maryland demonstrated that the SCR-720 radar could detect targets at up to 85 miles away. The third XF3D-1 was fitted with the APQ-35 radar, which was able to meet the requirement for detection at a range of 125 miles.
Flight tests were sufficiently favorable that a production contract for 28 F3D-1s for the Navy and Marine Corps was issued on May 11, 1948. Serials were BuNos 123741/123768.
In October of 1948, all three XF3D-1s were transferred to Muroc Dry Lake (later renamed Edwards AFB) for government trials. At about the same time, the Air Force was experiencing problems with the development of its own night fighters. The Curtiss XF-87 Nighthawk had been cancelled outright and the Northrop F-89 Scorpion had run into serious developmental problems, so the Air Force tested the XF3D-1 as a possible substitute. However, in the end the Air Force opted not to acquire the Skyknight, deciding instead to develop the interim Lockheed F-94 Starfire while they ironed out the problems with the F-89 Scorpion.
The production F3D-1 was to be fitted with a pair of Westinghouse J34-WE-34s, rated at 3250 lb.s.t. each. Since these engines were to have a larger diameter than the WE-22s fitted to the XF3D-1, the engine nacelles had to be made somewhat larger in order to accommodate them. In addition, the auxiliary tailwheel was beefed up and made more robust. Additional electronic gear was added and internal equipment was revised, which increased the gross weight by 5362 pounds. The F3D-1 was otherwise quite similar to the XF3D-1.
The first production F3D-1 flew on February 13, 1950, and was delivered to the Navy for testing in August of that year. Since the WE-34 engines were not yet available, the first few aircraft were delivered with 3000 lb.s.t J34-WE-32 engines. The thrust of the engines were later increased to 3250 lb.s.t. each, at which time they were redesignated J34-WE-34.
VC-3, based at Moffett Field, California, was the first squadron to take delivery of the Skyknight, which got its first planes in December of 1950. Shortly thereafter, F3D-1s were delivered to VMF(N)-542 at El Toro, to NATC, and to Point Mugu, California. Despite the demands of the Korean War, all of the F3D-1s were retained in the USA and were used for training of pilots and radar operators for fully-operational F3D-2s that were soon to be forthcoming.
In late 1952, XF3D-1 BuNo 121458 was fitted as the first test aircraft for the Sparrow I semiactive-homing radar-guided air-to-air missile. Air Development Squadron Four (VX-4) was assigned the initial development work. Tests were sufficiently encouraging that at least twelve F3D-1s were modified to test Sparrow missiles. Designated F3D-1M, they were fitted with four external stores pylons underneath the wing.
In September of 1962, surviving F3D-1s were redesignated F-10A under the new Tri-Service designation system. The F3D-1M became MF-10A.
Engines: Two Westinghouse J34-WE-34 axial-flow turbojets, each rated at 3250 lb.s.t. for takeoff. Performance: Maximum speed 530 mph at sea level, 565 mph at 20,000 feet, 425 mph at 40,000 feet. Cruising speed 428 mph. Stalling speed 107 mph. Initial climb rate 1960 feet per minute. Service ceiling 34,000 feet. Absolute ceiling 44,000 feet. Normal range 600 miles. Maximum range 1318 miles. Weights: 14,890 pounds empty, 24,485 pounds gross, 27,362 pounds maximum. Dimensions: wingspan 50 feet 0 inches, length 45 feet 5 inches, height 16 feet 1 inches, wing area 400 square feet. Fuel: Maximum internal fuel of 1350 US gallons. Two 150 US gallon drop tanks could be carried on underwing pylons, bringing total fuel capacity to 1650 US gallons. Armament: Four 20-mm cannon with 800 rounds. Two underwing pylons just inboard of the wing folding point which could carry up to 4000 pounds of bombs, rockets, or fuel tanks.
121457/121459 Douglas XF3D-1 Skyknight 123741/123768 Douglas F3D-1 Skyknight