The Vought F8U-1(F-8A) Crusader
(The Last of the Gunfighters)
In 1953 the F8U-1 Crusader won the Navy competition for the new carrier-based day fighter. It flew supersonic on its maiden flight in 1955. A Crusader set a national speed record in 1956 by flying over 1000 mph (1,609 km/h), for which it won the Thompson Trophy. In 1957 Major John Glenn flew an F8U non-stop from Los Angeles to New York, setting a transcontinental speed record. The average speed for the flight was Mach 1.1 despite three in-flight refuelling at speeds below 300 mph (483 km/h). In 1957 the Crusader won the Collier Trophy for its contributions to the advancement of aviation science. In 1958 Vought received the first Certificate of merit ever awarded an aircraft manufacturer by the Navy Bureau of Aeronautics for the design, development and production of a US Navy aircraft. In the Vietnam conflict the Crusader had the highest kill ratio over communist jets of any Navy aircraft. The F8U series enjoyed a long service life, which was extended in the 1960s by re-manufacturing and updating existing aircraft. Crusaders flew in Navy reserve units until 1987, and the French navy flew its Crusaders well into the 1990’s.
F8U-1 (F-8A)
With the rapid pace of the XF8U-1 flight test programme, and the almost non-existent requirement for major modifications to the aircraft as a result of flight test, fabrication of the production version of the Crusader followed that of the prototypes virtually uninterrupted, beginning at a rate of three per month, and soon accelerating to a rate of eight per month. As a result, the first production aircraft, F8U-1Bu.No. 140444 made its first flight on 30 September 1955, six months and five days after the initial flight of XF #1, and the production line continued to roll until 25 November 1963 when the last Crusader, F-8E (FN) Number 42 (Bu.No. 151773) completed final assembly.
F8U-1E (F-8B)
On 3 September 1958, BuNo. 145318 flew from NAS Dallas as the prototype model of the F8U-1E with a modified avionics system. This modification replaced the AN/APG-30 gun-ranging radar system with the AN/APS-67 radar scanner in the nose section of the aircraft. The change gave the Crusader a limited all-weather capability, and expanded its mission beyond the pure “day fighter” requirements of the original version. This version of the Crusader was identifiable externally by the new radome configuration - an all-plastic radome in lieu of the combination metal/plastic radome of the F8U-1. The new radome had a small glass window on the lower aft surface, which permitted a gun camera to record the results of gunfire runs. In all other respects, the F8U-1E was identical to the F8U-1. One-hundred-thirty of the F8U-1E models were built.
The Vought F8U Crusader was the first U.S.Navy aircraft capable of sustained supersonic flight and was the first Navy fighter capable of exceeding 1000 mph (1,609 km/h) in level flight. A total of 1,261 Crusaders were built. Forty-five years after the first flight of the prototype, the Crusader still served 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 (9,144 m) and Mach 0.9 at sea level, an initial climb rate of 25,000 feet (7,620 m) 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 mock-ups 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
The Vought proposal was designed around the Pratt & Whitney J57-P-11 axial flow turbojet, which offered 10,900 lb.s.t. (4944.24 kg) dry and 14,500 lb.s.t. (6577.2 kg) 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. Positioning and locking handles inside the cockpit operated the variable-incidence wing. When the wing is raised, the centre 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 in-flight 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 (where the wings are set an angle such that the tips are lower than the centre. The opposite of dihedral) 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 an 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. A small auxiliary door covered the aft portion of the retraction strut. 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 (70 mm) 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 (4,921.02 litres)
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. It is currently in storage at the Smithsonian's Silver Hill facility in Suitland, Maryland. The second prototype (138900) was scrapped after 460 flights.
The F8U-1 was the initial production version of the Crusader. The Crusader test flight programme had gone so smoothly that the production F8U-1 was almost identical to the XF8U-1 prototypes. The first production F8U-1 (BuNo 140444) flew for the first time on September 30, 1955, the same day as the maiden flight of the second XF8U-1.
The engine powering the F8U-1 was the J57-P-12A engine, which, after the delivery of the first few dozen aircraft, was supplanted by the J57-P-4A offering an afterburning thrust of 16,200 (7348.32 kg) pounds. The F8U-1 carried an APG-30 gun-ranging fire control radar.
From September of 1955, the Navy required that that all its carrier-based aircraft be equipped with midair refuelling capability. Production F8U-1s were equipped with a retractable refuelling probe enclosed underneath a blister on the left-hand side of the fuselage, just aft of the cockpit.
Initial carrier qualification tests took place aboard the USS Forrestal (CVA-59) with F8U-1 BuNo 140446 (the fourth pre-production F8U-1) in April of 1956. Patuxent test pilot Cdr R. W. "Duke" Windsor carried out the initial tests. The first catapult launch took place on 4th April.
The first production F8U-1s reached VX-3 in December of 1956. The first operational squadron to re-equip with the Crusader was VF-32 at NAS Cecil Field, Jacksonville, Florida in March of 1957, followed by West Coast squadrons VF-154 and VF (AW)-3, then by VF-211, VF-143, and VF-143. The first squadron to operate the F8U-1 aboard an aircraft carrier was VF-32, which embarked aboard the USS Saratoga towards the end of 1957. The first Marine Corps squadrons took their Crusaders in December of 1957--VMF-122, followed by VMF-312, VMF-333, and VMF-334.
In order to show off its new fighter, the Navy decided to use the Crusader to capture the World's air speed record, held at that time by the F-100C Super Sabre at 825 mph (1327.4 km/h). The Navy felt that the Crusader could beat that record by a substantial margin, perhaps even giving the Crusader the distinction of being the first aircraft to set a record that exceeded 1000 mph (1,609 km/h). However, on 19th March 1956, the Fairey Delta F.D.2, a British research aircraft, set a speed record of 1,132 mph (1821.4 km/h), 310 mph (498.8 km/h) greater than the previous record. Undaunted, the Navy went ahead with its plans, but since it did not want to reveal the full capabilities of the Crusader, the team was told to hold back, the only instructions being given to exceed 1000 mph. On August 21, 1956, Cdr "Duke" Windsor in F8U-1 BuNo 141345 (the twelfth production machine) hit an average speed of 1015.428 mph (1633.823 km/h) in two speed runs in opposite directions over a 15-kilometer course at an altitude of 40,000 feet (12,192 m) over China Lake, California. This set a new national speed record, and for this feat the Thompson Trophy was awarded to the Navy and to Vought.
On 6th June, 1957, two F8U-1s, piloted by Capt Robert G. Dose and Lt. Cdr. Paul Miller took off from the USS Bon Homme Richard (CVA-31) steaming off the California coast and flew to the USS Saratoga (CVA-60) waiting off the Florida coast. With one mid-air refuelling over Texas, the planes made the trip in 3 hours and 28 minutes. President Dwight Eisenhower was aboard the Saratoga to greet the crew as they landed.
A total of 218 F8U-1s were built before production switched in September of 1958 to the F8U-2.
Production aircraft up to and including the F8U-2N were initially fitted with a lightweight high-altitude ejection seat built by Vought. This was replaced in production aircraft by the Martin-Baker Mk F5 from the F8U-2NE onward, and was retrofitted to older aircraft from 1962 onward.
On September 18, 1962, the Crusader was re-designated F-8 under the new unified Tri-Service designation scheme. The F8U-1 became F-8A.
During 1966, Vought instituted a major re-manufacturing programme in which earlier Crusaders were to be modernized, re-equipped, and re-manufactured to bring them up to contemporary standards and increase their service lives. These remanufactured planes were then assigned new series letters. The designation F-8M had been reserved for F-8As that were originally scheduled to be remanufactured to later Crusader standards. However, by the time that the programme could get underway, there were very few F-8As still left, and the programme was abandoned before any F-8M conversions could be performed.
During 1967 a few F-8As were modified as directors for Regulus I and II drones and designated DF-8A. Utility squadrons such as VC-7 and VC-8 operated them. They were painted in bright colours and retained their cannon armament.
A few other F-8As became QF-8A drones. Sometimes they were known as DQF-8A. Two of these were operated by the Naval Missile Test Centre at Point Mugu, California and were used to guide and track the Regulus II, a submarine-launched cruise missile.
During the late 1950s there was a very real fear that the Soviets would soon have bombers capable of cruising at altitudes of over 60,000 feet (18,288 m). Along with several other companies, Vought sought means by which jet fighters could be able to reach such altitudes and deal with these threats. One technique that was studied was the installation of an auxiliary rocket engine that could help boost the fighter to such high altitudes. In 1957, Vought planned to install a rocket engine in the tail of a couple of F8U-1s (production numbers 16 and 23). The engine originally planned for this installation was the Reaction Motors XLF-40, which provided 8000 pounds (3,629 kg) of thrust and was fuelled by a mixture of hydrogen peroxide and jet fuel. Unfortunately, this rocket engine exploded during an early ground test, killing two company mechanics. This accident caused Reaction Motors to pull out of the project, but Vought elected to continue the project using a Rocketdyne XLF-54 engine, which gave 6000 pounds (2,722 kg) of thrust. Although the project never reached flight status, dummy engines were installed above the F8U-1's tail cone just behind the rudder.
In 1969, F-8A BuNo 141354 was turned over to NASA as number 666. It served at NASA's Lewis Research Centre as a chase plane for the NF-106B. It was lost in a landing accident later that same year.
F-8A BuNo 141353 was turned over to NASA for supercritical wing research. This type of airfoil reversed the shape of the conventional wing by having the top surface flat and the bottom surface curved. Such a wing allows an aircraft to cruise at speeds closer to Mach 1 without buffeting. It was also hoped that the supercritical wing would reduce takeoff and landing distances as well as contributing to improved low speed handling characteristics. Numbered NASA 810, this F-8A was fitted with a new supercritical wing that had a span of 43 feet (13.1). The slender long-span wings imparted a graceful, birdlike quality to the plane's appearance. Following the completion of its part in the programme, the supercritical wing programme was turned over to a converted General Dynamics F-111.
Vietnam Service
The F-8 Crusader was the last U.S. fighter designed with guns as its primary weapon. When conflict erupted in the skies over North Vietnam , it was U.S. Navy Crusaders that first tangled with Vietnam People's Air Force (VPAF) MiGs in August 1965. Although the MiGs claimed the downing of a Crusader, all aircraft returned safely. At the time, the Crusader was the best dogfighter the United States had against the nimble North Vietnamese MiGs. The Navy had evolved its "night fighter" role in the air wing to an all-weather interceptor, the F-4 Phantom II, equipped to engage incoming bombers at long range with missiles such as the Sparrow as their sole air-to-air weapons, and manoeuvrability was not emphasized in their design. Some experts believed that the era of the dogfight was over as air-to-air missiles would knock down adversaries well before they could get close enough to engage in dogfighting. As aerial combat ensued over North Vietnam from 1965 to 1968, it became apparent that the dogfight was not over and the F-8 Crusader and a community trained to prevail in air-to-air combat was a key ingredient to success.
Despite the "last gunfighter" moniker, the F-8s achieved only four victories with their cannon — the remainder were accomplished with AIM-9 Sidewinder missiles, partly due to the propensity of the Colt Mark 12 cannons' feeding mechanism to jam under G-loading during high-speed dogfighting manoeuvres. Nonetheless, the Crusader would be credited with the best kill ratio of any American type including the famed F-4 Phantom in the Vietnam War, 19:3.
USMC Crusaders flew only in the South, some operated in close air support missions. US Navy Crusaders of which there were only a few flew from the small Essex class carriers. The Crusader was used exclusively by the Navy and Marine air wings (although there is one U.S. Air Force pilot reported shot down in an F8) and represented half or more of the carrier fighters in the Gulf of Tonkin during the first four years of the war. The aircraft was credited with nearly 53% of MiG kills in Vietnam.The most frequently used fighter versions of the Crusader in Vietnam were the C, D, and E models although the H and J were also used.
The combat attrition rate of the Crusader was comparable to similar fighters. Between 1964 to 1972, eighty-three Crusaders were either lost or destroyed by enemy fire. Another 109 required major re-building, 145 Crusader pilots were recovered; 57 were not. Twenty of these pilots were captured and released. The other 43 remained missing at the end of the war.
