Korean War experience had demonstrated that 0.50 in (12.7 mm) machine guns were no longer sufficient and as the result the new fighter was to carry 20 mm (0.8 in) cannons. In response, the Vought team led by John Russell Clark created the V-383. Unusually for a fighter, the aircraft had a high-mounted wing which allowed for short and light landing gear. The most innovative aspect of the design was the variable-incidence wing which pivoted by 7° out of the fuselage on takeoff and landing. This afforded increased lift due to a greater angle of attack without compromising forward visibility because the fuselage stayed level. Simultaneously, the lift was augmented by leading-edge slats drooping by 25° and inboard flaps extending to 30°. The rest of the aircraft took advantage of contemporary aerodynamic innovations with area ruled fuselage, all-moving stabilators, dog-tooth notching at the wing folds for improved yaw stability, and liberal use of titanium in the airframe. Power came from the Pratt & Whitney J57 afterburning turbojet and the armament, as specified by the Navy, consisted of four 20 mm cannons, a retractable tray with 32 unguided Mighty Mouse FFARs, and cheek pylons for two AIM-9 Sidewinder air-to-air missiles. Vought also presented a tactical reconnaissance version of the aircraft called the V-382. Major competition came from Grumman with their General ElectricJ79-powered F-11 Tiger, McDonnell with upgraded twin-engine F3H Demon (which would eventually become the F-4 Phantom II), and North American with their F-100 Super Sabre adopted for carrier use and dubbed the Super Fury.
In May 1953, the Vought design was declared a winner and in June Vought received an order for three XF8U-1 prototypes (after adoption of the unified designation system in September 1962, the F8U became the F-8). The first prototype flew on 25 March1955 with John Conrad at the controls. The aircraft exceeded the speed of sound during its maiden flight. The development was so trouble-free that the second prototype, along with the first production F8U-1, flew on the same day, 30 September 1955. On 4 April1956, the F8U-1 performed its first catapult launch from USS Forrestal, and VF-32 Swordsmen began accepting first deliveries by March 1957.
Two Crusaders prepare to launch from USS Midway; their variable-incidence wings are in the "up" position.
Coming from a previous generation, the Crusader was the best dogfighter the United States had against Vietnamese MiGs. Later types, such as the F-4 Phantom II, had been expected to engage incoming bombers at long range with missiles such as Sparrow as their sole air-to-air weapons, and maneuverability was not emphasised in their design. The Crusader would be credited with the best kill ratio of any American type in the Vietnam War, 19:3, although most of its victories were achieved using AIM-9 Sidewinder missiles and not guns.Donald, D, Lake J. (ed.) (2002) McDonnell F-4 Phantom: Spirit in the Skies. AIRtime Publishing. ISBN 1880588315
The F-8E(FN) was used by the French Navy until 2000, when they were replaced by the Rafale M. Seventeen aircraft went through a limited service life extension program in 1991.
In late 1977, the Philippine government purchased 35 ex-US Navy F-8Hs that were stored at Davis-Monthan AFB in Arizona. Dubbed the F-8P, 25 of them were refurbished by Vought and the remaining ten were used for spare parts. As part of the deal, the US would train Philippine pilots in using the TF-8A. The F-8s were withdrawn from service beginning in 1988 and were finally withdrawn from service in 1991 after they were badly damaged by the Mount Pinatubo eruption and have since been offered for sale as scrap.
The Crusader was not a particularly easy airplane to fly and quite unforgiving on landings where it suffered from yaw instability. Not surprisingly, the accident rate was high compared to its contemporaries, the A-4 Skyhawk and the Phantom II.
The last Navy fighter Crusader were retired from VF-191 and VF-194 aboard USS Oriskany in 1976, although VFP-63 continued to fly reconnaissance RF-8Gs up to 1982.
In parallel with the F8U-1s and -2s, the Crusader design team was also working on a larger aircraft with ever greater performance, internally designated as the V-401. Although externally similar to the Crusader and sharing with it such design elements as the variable incidence wing, the new fighter was larger and was powered by the Pratt & WhitneyJ75-P-5A engine generating 29,500 lbf (131 kN) of afterburning thrust. To deal with Mach 2+ flight conditions, the aircraft was fitted with a complex variable air intake and large vertical ventral fins under the tail which rotated to the horizontal position for landing. To ensure sufficient performance, Vought made provisions for a Rocketdyne XLF-40 liquid-fuel rocket motor with 8,000 lbf (35.6 kN) of thrust in addition to the turbojet. Avionics included the AN/AWG-7 fire control computer, AN/APG-74 radar, and AN/ASQ-19 datalink. The system was expected to simultaneously track six and fire at two targets.
The F8U-3 first flew on June 21958. During testing, the aircraft reached Mach 2.6 at 35,000 ft (10,670 m). With Vought projecting a top speed of Mach 2.9, the Navy designated the project F8U-3 and in December of 1955 declared a competition for a Mach 2+ fleet defense interceptor. Flyoffs against the Crusader III's main competitor, the future F-4 Phantom II, demonstrated that the Vought design had a definite advantage in maneuverability. However, the solitary pilot in the F8U-3 was easily overwhelmed with the workload required to fly the intercept and fire Sparrows which required constant radar illumination from the firing aircraft, while the Phantom II had a dedicated radar intercept officer onboard. In addition, with the perception that the age of the guns was over, the Phantom's considerably larger payload and the ability to perform air-to-ground as well as air-to-air missions, trumped Vought's fast but single-purposed fighter. The F8U-3 program was cancelled with five aircraft built. None have survived to this day.
*XF8U-1 (XF-8A) - the two original unarmed prototypes. *F8U-1 (F-8A) - first production version, J57-P-12 engine replaced with more powerful J57-P-4A starting with 31st production aircraft, 318 built. *YF8U-1 (YF-8A) - one F8U-1 fighter used for development testing. *YF8U-1E (YF-8B) - one F8U-1 converted to serve as a F8U-1E prototype. *F8U-1E (F-8B) - added a limited all-weather capability thanks to the AN/APS-67 radar, the unguided rocket tray was sealed shut because it was never used operationally, first flight 3 September 1958, 130 built. *YF8U-2 (YF-8C) - two F8U-1s used for flight testing the J57-P-16 turbojet engine. *F8U-2 (F-8C) - J57-P-16 engine with 16,900 lbf (75 kN) of afterburning thrust, ventral fins added under the rear fuselage in an attempt to rectify yaw instability, Y-shaped chin pylons allowing two Sidewinder missiles on each side of the fuselage, first flight 20 August 1957, 187 built. *F8U-2N (F-8D) - all-weather version, unguided rocket pack replaced with an additional fuel tank, J57-P-20 engine with 18,000 lbf (80 kN) of afterburning thrust, landing system which automatically maintained present airspeed during approach, first flight 16 February 1960, 152 built. *YF8U-2N (YF-8D) - one aircraft used in the development of the F8U-2N. *YF8U-NE - one F8U-1 converted to serve as a F8U-2NE prototype. *F8U-2NE (F-8E) - J57-P-20A engine, AN/APQ-94 radar in a larger nose cone, dorsal hump between the wings containing electronics for the AGM-12 Bullpup missile, payload increased to 5,000 lb (2,270 kg), Martin-Baker ejection seat, first flight 30 June 1961, 286 built. *F-8E(FN) - air superiority fighter version for the French Navy, significantly increased wing lift due to greater slat and flap deflection and the addition of a boundary layer control system, enlarged stabilators, 42 built. *F-8H - upgraded F-8D with strengthened airframe and landing gear, 89 rebuilt. *F-8J - upgraded F-8E, similar to F-8D but with wing modifications and BLC like on F-8E(FN), "wet" pylons for external fuel tanks, J57-P-20A engine, 136 rebuilt. *F-8K - upgraded F-8C with Bullpup capability and J57-P-20A engines, 87 rebuilt. *F-8L - F-8B upgraded with underwing hardpoints, 61 rebuilt. *F-8P - refurbished F-8Hs in Philippine service, 35 delivered (25 aircraft plus 10 spares). *F8U-1D (DF-8A) - several retired F-8A modified to controller aircraft for testing of the SSM-N-8 Regulus cruise missile. *DF-8F - retired F-8A modified for target tug duty *F8U-1KU (QF-8A) - retired F-8A modified into remote-controlled target drones *YF8U-1P (YRF-8A) - prototypes used in the development of the F8U-1P photo-reconnaissance aircraft. *F8U-1P (RF-8A) - unarmed photo-reconnaissance version of F8U-1E, 144 built. *RF-8G - modernized RF-8As *XF8U-1T - one XF8U-2NE used for evaluation as a two-seat trainer. *F8U-1T (TF-8A) - two-seat trainer verion based on F8U-2NE, fuselage stretched 2 ft (0.61 m), internal armament reduced to two cannons, J57-P-20 engine, first flight 6 February 1962. The Royal Navy was initially interested in the Rolls-Royce Spey-powered version of TF-8A but chose the Phantom II instead. Only one TF-8A was built, although several retired F-8As were converted to similar two-seat trainers. *F8U-3 Crusader III - new design loosely based on the earlier F-8 variants, created to compete against the F-4 Phantom II, J75-P-5A engine with 29,500 lbf (131 kN) of afterburning thrust, first flight 2 June 1958, attained Mach 2.6 in test flights, cancelled after 5 aircraft because the Phantom II won the Navy contract.
armament= *4x 20 mm Colt Mk 12 cannons in the lower fuselage (125 rounds per gun, 500 rounds total) *Up to 5,000 lb (2,270 kg) externally, including 4x AIM-9 Sidewinder air-to-air missiles, 2x AGM-12 Bullpup air-to-ground guided missiles, 8x Zuni rockets in four twin pods, up to 12x 250 lb (113 kg) bombs, or up to 4x 1,000 lb (454 kg) bombs, or 2x 2,000 lb (907 kg) bombs.
