The Vought F8U Crusader was the first Navy aircraft capable of sustained supersonic flight and was the first Navy fighter capable of exceeding 1000 mph in level flight. A total of 1261 Crusaders were built. Forty-five years after the first flight of the prototype, the Crusader still serves with the French Navy.
In September of 1952, the Navy issued a Request For Proposals for a new carrier-based day fighter capable of Mach 1.2 at 30,000 feet and Mach 0.9 at sea level, an initial climb rate of 25,000 feet per minute, and a landing speed of only 100 knots. The RFP was issued to McDonnell, North American, Douglas, Convair, Lockheed, Grumman, Vought, and Republic. Of these, only Douglas, McDonnell, Grumman, and Vought had any real experience with carrier-based aircraft.
The Chance Vought company of Dallas, Texas went to work on their proposal. At that time, Chance Vought was a part of the United Aircraft Corporation. Vought engineer John Russell Clark led the design team. He had worked on the F6U Pirate and the F7U Cutlass.
A total of 21 proposals were submitted from eight different aircraft companies. The most viable proposals were deemed by the Navy to be the Grumman XF11F-2 (a version of the F11F Tiger powered by the General Electric J79), the McDonnell F3H-G (a twin-engined adaptation of the F3H Demon), and the North American "Super Fury" (a navalized F-100), plus the Vought submission, which was given the company designation V-383.
In May of 1953, the Navy selected the Vought V-383 as the winner of the competition. The Navy at that time ordered several mockups and wind tunnel test models. The designation XF8U-1 was assigned. At the same time, the reconnaissance version, V-392, was also ordered under the designation F8U-1P.
The Vought proposal was designed around the Pratt & Whitney J57-P-11 axial flow turbojet, which offered 10,900 lb.s.t. dry and 14,500 lb.s.t. with afterburning. The most unusual feature of the Vought design was the use of a high-mounted swept wing whose angle of incidence could be varied in flight. During takeoff or landing, the angle of incidence could be increased by seven degrees, which enabled the wing to retain a high-angle of attack during takeoff and landing, and yet enabled the fuselage to remain fairly level for better forward visibility. The variable-incidence wing was operated by positioning and locking handles inside the cockpit. When the wing is raised, the center section protrudes into the airstream, thereby acting as a large speed brake. The ailerons and the entire wing leading edge surfaces were interconnected and were automatically lowered to 25 degrees when the wing was raised to increase the camber and thus the lift. Inboard of the ailerons were a pair of small landing flaps which extended about five degrees more than the ailerons. When the wing was lowered after takeoff, all the surfaces returned to their normal inflight positions, with the leading edge going to the position selected for the cruise droop. Aerodynamically, it was actually the fuselage that was being raised, since the wing was doing the flying. Landing with the wing down was always possible ashore, but very risky aboard ship, although it was done successfully on several occasions.
The wing had a sweepback of 42 degrees at one-quarter chord and a total area of 350 square feet. The anhedral was five degrees. The outer wing panels folded vertically upward for carrier stowage and carried no control surfaces. However, they still had the drooping leading edge, providing a characteristic "dog-tooth", a chord-wise outer wing extension to decrease instability when approaching the stall and to minimize pitch-up tendency at high speeds.
The fuselage conformed to the Area Rule, in which the cross-section of the fuselage was narrowed in the region of the wing. Extensive use was made of titanium, with the rear fuselage around the afterburner being constructed of this metal, plus extensive parts of the central structure. The extreme nose housed the fire control radar, and the J57 engine was fed by a oval chin-type intake located underneath the radome. The all-flying tailplane was mounted low on the rear fuselage and had a slight dihedral.
The variable-incidence wing obviated the need for a stalky forward landing gear leg to keep the nose up during takeoff and landing, which in turn make it possible to keep the gear relatively strong and of low weight. The main landing gear members retracted forward into bays in the lower fuselage. The aft portion of the retraction strut was covered by a small auxiliary door. The nose landing gear member was fully steerable and retracted rearwards into the fuselage.
A ram-air turbine was installed on a hinged panel in the right side of the forward fuselage. When extended into the airstream, it could provide emergency hydraulic and electrical power.
The planned armament was four 20-mm Colt Mk 12 cannon, two on each side of the forward fuselage, with 144 rounds per gun. In addition, there was to be provision for cheek rails immediately aft of the cockpit for a single Sidewinder air-to-air missile, one on each side. A retractable rocket pack housing 32 2.75-inch unguided rocket was to be installed in the fuselage belly just underneath the air brake. The rocket pack was supposed to be used in anti-bomber attacks or for ground attack work.
The internal fuel supply included more than 1300 US gallons in wing and fuselage fuel tanks.
On June 29, 1953, the Navy ordered three prototypes under the designation XF8U-1. Bureau of Aeronautics serial numbers were 138899 through 138901. Only two of these prototypes were actually built, 138901 being cancelled before it could be built.
The first prototype (BuNo 138899) was ready for its first flight in February of 1955. It was trucked out to Edwards AFB for its first flight. It took off on its maiden flight on March 25, 1955, Vought chief test pilot John Konrad being at the controls. It went supersonic on its first flight.
The second prototype (138900) flew for the first time on September 30, 1955. It was essentially identical to the first.
138899 made 508 flights during its five years of testing. In 1960, it was donated to the Smithsonian Institution in Washington and placed in storage at the Smithsonian's Silver Hill facility in Suitland, Maryland. It is reported now to be at the Seattle Museum of Flight restoration facility in Everett, WA. The second prototype (138900) was scrapped after 460 flights.
138899/138901 Chance Vought XF8U-1 Crusader (138901 cancelled)