The Vought F-8 Crusader (originally F8U) is a single-engine, supersonic, carrier-based air superiority jet aircraft built by Vought for the United States Navy and United States Marine Corps, and for the French Navy.
The first F-8 prototype was ready for flight in February 1955.
The F-8 served principally in the Vietnam War.
The Crusader was the last American fighter with guns as the primary weapon.
The RF-8 Crusader was a photo-reconnaissance development and operated longer in U.S. service than any of the fighter versions.
RF-8s played a crucial role in the Cuban Missile Crisis, providing essential low-level photographs impossible to acquire by other means.
United States Navy Reserve units continued to operate the RF-8 until 1987.
In September 1952, the United States Navy announced a requirement for a new fighter.
It was to have a top speed of Mach 1.2 at 30,000 ft (9,144.0 m) with a climb rate of 25,000 ft/min (127.0 m/s), and a landing speed of no more than 100 mph (160 km/h).
Korean War experience had demonstrated that 0.50-inch (12.7 mm) machine guns were no longer sufficient and as a result the new fighter was to carry a 20 mm (0.79 in) cannon. 4×20 mm had become Navy standard prior to the Korean war: F2H, F9F, F3D and also the F7U and F4D, among others, preceded the F8U.
In response, the Vought team led by John Russell Clark, created the V-383.
Unusual for a fighter, the aircraft had a high-mounted wing which necessitated the use of a fuselage-mounted short and light landing gear.
The major contribution to the short main gear, however, was the variable incidence wing that meant the plane did not take off and land extremely nose up, which was a characteristic of swept and low aspect ratio winged fighters.
The Crusader was powered by a Pratt and Whitney J57 turbojet engine.
The engine was equipped with an afterburner which, on the initial production F8U-1 aircraft, increased the thrust of the engine from 10,200 lb to 16,000 lb, but, unlike later engines, had no intermediate thrust settings.
The Crusader was the first jet fighter in US service to reach 1,000 mph: U.S. Navy pilot R.W. Windsor reached 1,015 mph on a flight in 1956.
The most innovative aspect of the design was the variable-incidence wing which pivoted by 7° out of the fuselage on take-off and landing (not to be confused with variable-sweep wing).
This allowed a greater angle of attack, increasing lift without compromising forward visibility.
This innovation helped the F-8’s development team win the Collier Trophy in 1956.
Simultaneously, the lift was augmented by leading-edge flaps 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, dogtooth notching at the wing folds for improved yaw stability, and liberal use of titanium in the airframe.
The armament, as specified by the Navy, consisted primarily of four 20 mm (.79 in) autocannons; the Crusader happened to be the last U.S. fighter designed with guns as its primary weapon.
They were supplemented with a retractable tray with 32 unguided Mk 4/Mk 40 Folding-Fin Aerial Rocket (Mighty Mouse FFARs), and cheek pylons for two guided AIM-9 Sidewinder air-to-air missiles.
In practice, AIM-9 Sidewinder missiles were the F-8’s primary weapon; the 20mm guns were “generally unreliable”. Moreover, it achieved nearly all of its kills with Sidewinders.
Vought also presented a tactical reconnaissance version of the aircraft called the V-392.
Major competition came from the Grumman F-11 Tiger, the upgraded twin-engine McDonnell F3H Demon (which would eventually become the McDonnell Douglas F-4 Phantom II), and lastly, the North American F-100 Super Sabre hastily adapted to 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 March 1955 with John Konrad 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 April 1956, the F8U-1 performed its first catapult launch from Forrestal.
Crusader III
In parallel with the F8U-1s and -2s, the Crusader design team was also working on a larger aircraft with even greater performance, internally designated as the V-401.
Although the Vought XF8U-3 Crusader III was externally similar to the Crusader and sharing with it such design elements as the variable incidence wing, the new fighter was larger and shared few components.
Variants
XF8U-1
(XF-8A) (V-383)
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 an 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.
XF8U-1T
One XF8U-2NE used for evaluation as a two-seat trainer.
F8U-1T
(TF-8A) (V-408)
Two-seat trainer version based on F8U-2NE, fuselage stretched 2 ft (0.61 m), internal armament reduced to two cannon, 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.
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 cheek pylons allowing two Sidewinder missiles on each side of the fuselage, AN/APQ-83 radar retrofitted during later upgrades.
First flight: 20 August 1957, 187 built.
This variant was sometimes referred to as Crusader II.
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, incorporation of AN/APQ-83 radar.
First flight: 16 February 1960, 152 built.
YF8U-2N
(YF-8D)
One aircraft used in the development of the F8U-2N.
YF8U-2NE
One F8U-1 converted to serve as an 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, AN/APQ-94 radar replaced AN/APQ-83 radar in earlier F-8D.
IRST sensor blister (round ball) was added in front of the canopy.
First flight: 30 June 1961, 286 built.
F-8E(FN)
Air superiority fighter version for the French Navy, significantly increased wing lifts due to greater slat and flap deflection and the addition of a boundary layer control system, enlarged stabilators, incorporated AN/APQ-104 radar, an upgraded version of AN/APQ-94.
A total of 42 built.
F-8H
Upgraded F-8D with strengthened airframe and landing gear, with AN/APQ-84 radar.
A total of 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, with AN/APQ-124 radar.
A total of 136 rebuilt.
F-8K
Upgraded F-8C with Bullpup capability and J57-P-20A engines, with AN/APQ-125 radar.
A total of 87 rebuilt.
F-8L
F-8B upgraded with under wing hardpoints, with AN/APQ-149 radar.
A total of 61 rebuilt.
F-8P
17 F-8E(FN) of the Aéronavale underwent a significant overhaul at the end of the 1980s to stretch their service life another 10 years.
They were retired in 1999.
F8U-1D
(DF-8A)
Several retired F-8A modified to controller aircraft for testing of the SSM-N-8 Regulus cruise missile.
DF-8A was also modified as drone (F-9 Cougar) control which were used extensively by VC-8, NS Roosevelt Rds, PR, Atlantic Fleet Missile Range.
DF-8F
Retired F-8A modified as controller aircraft for testing of missiles including at the USN facility at China Lake.
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 – V-392.
F8U-1P
(RF-8A)
Unarmed photo-reconnaissance version of F8U-1E, 144 built.
RF-8G
Modernized RF-8As.
LTV V-100
Revised “low-cost” development based on the earlier F-8 variants, created in 1970 to compete against the F-4E Phantom II, Lockheed CL-1200 and F-5-21 in a tender for U.S. Military Assistance Program (MAP) funding.
The unsuccessful design was ultimately only a “paper exercise.”
XF8U-3 Crusader III
(V-401)
A 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 2.39 in test flights, cancelled after five aircraft were constructed because the Phantom II won the Navy contract.
