The Vought F-8 Crusader Was The US Navy’s Last Traditional Dogfighting Jet
Marketed as ‘Last of the Gunfighters’ and nicknamed the ‘Gator’ by ship deck crews, the Vought F-8 Crusader (F8U before 1962) was the US Navy’s first supersonic, carrier based fighter*. Taking advantage of a ‘coke bottle’ fuselage profile typical of late 1950s jet fighters, the Crusader outperformed the US Air Force’s F-100 Super Sabre in almost every respect even though they both used the same J57 engine. While US Navy and Marine Corps Crusaders were best known for jousting with North Vietnamese MiG fighters and lashing communist ground targets, unarmed reconnaissance RF-8s helped prevent World War III during the Cuban Missile Crisis prior to their participation in the Southeast Asian theatre. Despite its popularity with American naval aviators, the Crusader was steadily supplanted by the rival F-4 Phantom II and only exported in modest quantities to two foreign users.
To meet the US Navy’s September 1952 tender for an advanced carrier fighter capable of attaining Mach 1.2 at 30000 feet, maintain Mach 0.9 at sea level and climb at 25000 ft/minute, Chance Vought Aircraft had to tackle several contradictory stipulations peculiar to carrier based aircraft. Possessing high engine power was desirable in any fighter aircraft so it could rapidly climb to meet or escape its enemies. It was even more urgent for carrier based fighters, which needed a decent amount of thrust at short notice to clear the flat top if the deck officer waved off their landing as unsafe. Conversely, landing on a carrier’s short deck required a fighter to lower its airspeed substantially by angling itself upwards for a high angle of attack (AOA) because lowering its engine speed too much would sink the aircraft too rapidly. The corresponding upwards tilt of the nose would inevitably block a pilot’s view of a carrier’s deck, which could prove fatal in foul weather and low light conditions, not to mention the vicissitudes of battle damage and pilot fatigue. Finally, all carrier aircraft tended to be heavier, costlier and more complex than their land based counterparts owing to reinforced landing gear to withstand the impact of carrier landings, folding wings to facilitate storage and arrestor hooks.
Vought’s combat aircraft designs in the decade prior to the XF8U-1 Crusader prototype’s first flight in March 1955 embodied many of these problems. The F4U Corsair which ravaged Japanese and Communist adversaries in World War 2 and Korea packed aggressive amounts of power in its Pratt & Whitney Double Wasp but was difficult to land on carriers owing to that engine’s length blocking the pilot’s view. The F6U Pirate, Vought’s first jet fighter, was discharged from the Navy without gaining operational status because its feeble engines rendered it too unsafe for carrier operations. As for the arrow fletching shaped F7U Cutlass, it compensated for its low engine thrust by requiring an unusually high AOA when landing, which escalated the potential for accidents. The Cutlass’s 12 foot high nose wheel not only reduced the view while taxiing and proved an adventure to board; it was rumoured to skewer pilots if shoved upwards into the cockpit from a hard landing.
Departing from Vought’s maritime scoundrel naming convention (Corsair, Pirate, Cutlass) for a warrior like theme, the F8U Crusader overcame the high AOA and reduced the pilot visibility problem with a ‘variable incidence’ wing. They formed a single flap which could tilt upwards 7⁰ with a hydraulic jack to create the necessary AOA for lowered airspeed and a steady descent while keeping the fuselage pointing straight ahead, providing the pilot a clear view of his landing spot. Like the Air Force’s ‘Century Series’ fighters and its naval peer the Grumman F11F (F-11 after 1962) Tiger, the Crusader took advantage of a narrow ‘area rule’ fuselage with a pinched waist to reduce drag in transonic flight. With high mounted wings and squat undercarriage, the Crusader’s low crawling motion and menacing intake posed the constant threat of consuming careless sailors and pilots, bringing forth the nickname ‘The Gator’.
Following the successful flight of the two XF8U-1 prototypes, five further fighter models of Crusader which progressively added more capable radars and engines were produced. When the US Navy and Marine Corps revised their aircraft designations to match the Air Force’s nomenclature, the F8U was renamed the F-8 on 18 September 1962.
While the author has avoided exhaustively describing the diverse radar and engine progressions in the text (see table below for clarity), it is worth noting commonalities and other distinguishing features of the original A — E Crusader models. All F-8 fighters were armed with four Mk 12 cannons of 20mm calibre; two were mounted on each side of the fuselage just below the cockpit canopy. The modest carriage of 110–125 rounds per gun and the prioritizing of ECM (electronic countermeasures) hardware over enlarged magazines during the Vietnam War gave the pilot only 13 seconds firing time. Training squadron VF-124 came up with a field modification permitting the pilot to conserve rounds by selecting either the upper or lower cannons over simultaneous fire. Although the F-8 was constantly touted as the ‘Last of the Gunfighters’ as a snarky put down of the gun-less F-4 Phantom II, the temperamental weapons were prone to stoppages during any turns exceeding 3.5 G.
Another feature common to all Crusader models was the Ram Air Turbine. A pop out device on the aircraft’s right fuselage which used the slipstream to generate emergency electrical and hydraulic power, the RAT provided back up controls to a pilot struggling to return a damaged aircraft to base.
The first production F8U-1 (F-8A) Crusader, of which 318 were built, was a daytime only aircraft which housed the AN/APG-30 rangefinder gunsight dating back to the obsolete F-84E Thunderjet in a tiny nose cone. Along with the cannons, an internal ordnance pack housing 2.75 inch Mighty Mouse rockets hinged down from the Crusader’s belly for salvo firing. The integral rockets were almost never used operationally — aside from mediocre accuracy, their queued arrangement of 32 projectiles in tandem rows turned explosively messy if a misfired round from the front row blocked the next one out. A jammed open rocket pack could also stop the nose wheel flap from lowering for landing. The 31st F8U-1 to be built onwards replaced the original J57-P-12 engine with the J57-P-4A; this stronger engine also equipped the limited all weather capability F8U-1E (F-8B).
The 32nd F8U-1’s airframe formed the basis of the photo reconnaissance F8U-1P (RF-8A); the guns and fire control hardware were displaced in favour of five camera stations. Station 1 was a forward facing pod mounted directly under the cockpit for snapping approach imagery to a target. Directly behind Station 1 were two K-17 vertical/oblique cameras (Stations 3 and 4) followed by a trio of 70mm CAX-12 trimetrogen cameras for panoramic images (Station 2). Station 5 occupied the nose cone; rather than cameras or the original rangefinder gunsight, it housed an aiming periscope for the pilot to line up his aircraft to the target prior to snapping photos.
Produced in August 1958 and named the ‘Crusader II’ by Vought — the title did not stick — the F8U-2 (F-8C) differed externally from preceding models by adding afterburner cooling intakes over the tail cone and a pair of long strakes on the ventral surfaces below the engine. The original fuselage mounted rails which could only carry one AIM-9 Sidewinder air to air missile were supplanted by Y-racks which doubled the Crusader’s missile payload from two to four. Internally, Vought’s proprietary ejection seat was replaced by a Martin Baker Mk 5, complying with the Navy’s drive to standardize equipment and simplify training. While the ventral strakes were aimed at improving flight stability, they precluded skidding the aircraft like a flying dirt bike, an evasive manoeuvre which was only possible on earlier models.
The F8U-2N (F-8D) finally deleted the redundant internal rocket pack for an additional fuel tank and was distinguished as the first night capable Crusader model. Regarded as the fastest of its kind owing to its J57-P-20A engine boosting 18000 lbs thrust, the -2N added an AN/AAS-15 infrared search and track (IRST) sensor directly above its AN/APQ-83 radar. The radar guided AIM-9C Sidewinder was exclusively developed for compatibility with the F-8D onwards but was a rarely used anomaly compared to its infrared guided sisters.
Last of the ‘new build’ Crusaders, the F8U-2NE (F-8E) added electronics for launching the anaemic AGM-12 Bullpup air to ground missile within a dorsal spine and underwing hardpoints, granting the Crusader more loading options as a ground attack fighter. While a mission planner may have appreciated the E model’s expanded capabilities with these changes, pilots who believed the Crusader should stay a pure dogfighter were lukewarm about its increased weight. France took an interest in this model of Crusader and ordered 42 for its naval air arm, the Aeronavale. Their specially built F-8E (FN)’s most important feature was the boundary layer control system (BLCS). BLCS worked by channelling engine bleed air over the flap and ailerons’ upper surfaces, granting these export Crusaders enhanced performance at slow speeds when working with France’s Clemenceau class carriers which were smaller than most of the US Navy’s.
Crusaders on the Precipice of Nuclear Apocalypse
The US Navy was quite pleased with the Crusader and enthusiastically set speed records and milestones with their acquisition. These pursuits included the first transcontinental flight in history between two aircraft carriers on 6 June 1957 and Project BULLET, a high-speed photographic race from Los Angeles to New York City completed the next month by future astronaut and senator Major John Glenn.
Demonstrating an aircraft’s prowess through publicity exercises was undoubtedly glamourous but the Crusader was built to fight a war. Or in its first deployment in hostile territory, playing a part in preventing a nuclear conflict. In October 1962, American U-2 spy planes discovered Soviet R-12 and R-14 ballistic missiles along with their support assets in Cuba. Each of these medium and intermediate range weapons could accommodate 1 megaton nuclear warheads, 70 times more potent than those that obliterated Hiroshima. Nikita Khrushchev, the Soviet premier, had fortified the island to bolster his communist ally Fidel Castro following the Bay of Pigs invasion and as a riposte to US Jupiter missiles in Turkey.
Unable to countenance the presence of hostile nuclear sites just over 150 miles from the southern Florida coastline, President John F Kennedy, his Cabinet and the US military needed images of their disposition — either for showcasing evidence to the rest of the world or to plan their destruction if diplomacy failed. U-2 photos taken from above 70000 feet lacked detail for US diplomats to present to the United Nations; Corona satellites higher up in space were no better owing to cloud cover and their limited time over the area while in orbit. As participants in Operation BLUE MOON, RF-8A Crusaders of the US Navy’s light photo recon squadron VFP-62 skimmed over Cuba at below 1000 feet, dodging anti-aircraft fire to capture the locations of the Soviet missile sites and their garrisons. Without the benefits of modern GPS navigation devices, the recon aviators had to cross check landmarks with maps and compasses. Once the cameras were activated, the recon pilots had to stick to straight and level flight since sudden evasive moves may distort the photos beyond recognition.
Such was the importance of these missions and their frequency that four US Marine pilots from VMCJ-2 were seconded to VFP-62 to relieve fatigue amongst their original complement. Following the diplomatic resolution to the crisis and withdrawal of the Soviet missiles — their removal was studiously photographed for verification — Kennedy bestowed the pilots of VFP-62 and VMCJ-2 the Distinguished Flying Cross in recognition of their part in stopping World War 3. VFP-62 also received the Navy Unit Commendation, the first time this award was granted outside of wartime.
Vietnam and Modernization
It was in Southeast Asia that the Crusader earned the bulk of its acclaim. In June 1964, Lieutenant Charles Klusmann became the first American to be shot down and captured by Pathet Lao communist guerrillas in Laos. Just two weeks before he had returned to his carrier in flames after his aircraft was perforated with anti-aircraft fire. Klusmann would be the first of very few Americans to escape PL captivity and his RF-8A marked the first combat loss of a Crusader. Two months later, armed Crusaders drew their first blood when they shot up North Vietnamese torpedo boats who were confronting American destroyers on a spying mission off North Vietnam’s coast. These Gulf of Tonkin incidents became President Lyndon Johnson’s casus belli for the aerial campaign against North Vietnam.
How a Secret Campaign in Laos transformed the CIA
While studying the Vietnam War, most readers and students may have noted that Laos was the place where most of North…
Navy Crusaders served mainly as escort fighters for A-4 Skyhawk light attack bombers while their photo recon incarnations gathered information for planning strikes and assessing their effectiveness during Operation ROLLING THUNDER, the bombing campaign against North Vietnam which lasted from 1965–68. Further south in the Republic of Vietnam, US Marine Crusaders were almost exclusively used for the Close Air Support (CAS) role.
As early as the first year of American main force commitment to Vietnam (1965), the now renamed Ling Temco Vought (LTV) began rebuilding Crusaders to extend their service lives. What was common to all these remanufactured Crusaders, whose designations ran from G to L (excluding ‘I’), was their reinforced landing gear and new wings.
For ease of reading, the full list of the rebuilt Crusaders’ modifications are listed in the table below. The most significant changes worth noting was the fact that the RF-8G, along with an altered camera layout to stations 3 and 4, added the ventral strakes first introduced in the F-8C; these replaced the RF-8A in Vietnam by 1966. The F-8J was likely the least popular of the rebuilds; its most consequential features were the BLCS and enlarged horizontal stabilizer (called the ‘Unit Horizontal Tail’ by Vought) from the French Navy’s F-8E (FN). The additional weight of these alterations subtracted the F-8J’s reserve power required for safe carrier landings and were only addressed satisfactorily by installing the J57-P-420 powerplant.
Plenty of literature on the F-8 in the Southeast Asian theatre compare it to the F-4 Phantom, which fought alongside and gradually replaced the Crusader except for on the ’27 Charlie’ Essex class carriers which were too small to accommodate the Phantom. RF-8Gs gave way to the majestic RA-5C Vigilante and RF-4B Phantom II in US Navy (again, only on large carriers) and US Marine recon squadrons respectively. However, it is worth considering an alternative match up to a US Air Force fighter that used the same J57 engine as the Crusader: the North American F-100 Super Sabre.
In performance terms, the Crusader outdid the Super Sabre in most respects. The F-8E, which was the most common variant used in Vietnam, had a maximum speed of 1135 mph (1826 km/h) while the most prolific Super Sabre, the F-100D, was left behind at 864 mph (1390 km/h). Most Crusader variants could climb at 21000 feet/min (6400 meters/min) over the F-100’s 16000 feet/min (4900 meters/minute). While the F-8E’s ceiling topped out at 58000 feet (17676 meters), the highest the F-100D could reach was 55000 feet (16764 meters). Only in range was the Super Sabre superior: the F-100D could travel out to 1970 miles (3170 km) but the F-8E, which did not have drop tank capability until its F-8J rebuild, managed a modest 450 miles (724 km).
The career paths and milestones of the F-8 and F-100 diverged significantly in Vietnam. The F-8 was a formidable air to air duellist, claiming 14–16 VPAF MiG-17s and 4 MiG-21s between 1966–68. Pilots remained confident in the Crusader for air superiority owing to its competitive speed and manoeuvrability against MiGs. Just one F-100D scored an unconfirmed MiG-17 kill in April 1965; after this encounter F-100s were rapidly replaced by F-4C Phantoms and F-104C Starfighters in the CAP role. The F-100’s sluggish acceleration and stall following the loss of airspeed during tight turns left it wide open in a dogfight. Single seat F-100s were relegated to ground attack missions over South Vietnam, where their four 20mm cannon, heavy payload and durability made them highly dependable.
While only one F-8A was converted into a two seater and never deployed in Vietnam, the two seat F-100F (339 built) evolved from its intended trainer role as the first Wild Weasel air defence suppressor and as ‘Misty’ fast Forward Air Controllers.
‘The Best Fighter Never Produced’, NASA Technology and Retirement
A notable off shoot of the F-8 which first flew in June 1958 was the XF8U-3 ‘Super Crusader’, which competed against the McDonell Phantom II (still called the XF4H-1 in its prototype stage) for consideration as a high speed fleet defence interceptor. The Super Crusader’s most distinctive feature was its slanting scoop intake and vertical ventral fins for flight stability at Mach 2 which folded into horizontal position for ground taxiing, evoking the image of a rocket powered basking shark. The XF8U-3’s monstrous acceleration and speed were due to its J75-P-5A turbojet, pushing out 29500 lb afterburner thrust compared to the F-8E’s 18000 lbs. Rather than the guns that its F-8 cousins were touted for, the Super would have used Sparrow radar guided missiles as their primary armament for eliminating adversaries beyond visual range. Unfortunately for Vought the XF4H-1 Phantom won the competition, leaving the five Super Crusader airframes to be scrapped after a brief tenure with NASA.
NASA also used an F-8C from 1972–85 to pioneer the development of Digital Fly By Wire (DFBW) technology. DFBW’s electronic wiring mated to a flight computer was envisioned to be superior to hydraulic aided cable controls and push rods because they accorded near instantaneous aircraft reaction to a pilot’s stick and rudder movement, was less susceptible to battle damage, lighter and lower maintenance. Lastly, a flight computer permitted more flexibility in aircraft design since the stability required to compensate for the relative slowness of manual controls could be sacrificed for more manoeuvrability. DFBW has since been implemented in almost all military and civilian airliners since the 1980s.
LTV resurrected the Crusader’s body in designing the stubby A-7 Corsair II, a light attack bomber which dispensed with the variable incidence wing or supersonic capability. A-7s serving in Vietnam would usurp the A-4 Skyhawk’s position on board Navy carriers and take the A-1 Skyraider’s place in the Air Force’s Combat Search and Rescue escort mission.
The last Crusader fighters in American service were discharged by May 1976, the same year the final Essex class carriers ended their cruises. RF-8Gs outlived their fighter sisters in Navy Reserve squadrons until 1987. In 1977, the Philippines Air Force acquired 35 F-8Hs, renamed as F-8Ps; the last examples were junked after their exposure to the volcanic ash depredations of Mount Pinatubo’s eruption in 1991. France managed to squeeze several more years into their Crusaders’ lifespan with avionics updates and the addition of a radar warning receiver to the vertical tail fin; the resulting F-8Ps (P for prolonge and distinct from the similarly named Filipino models) were retired in 1999.
* ‘First supersonic carrier based fighter’ is disputed as the Douglas F4D (F-6) Skyray and Grumman F11F (F-11) Tiger have also been cited for this accolade. According to this blog article by naval aviation historian Tommy Thomason, the F4D struggled to attain supersonic speed in level flight notwithstanding Douglas’s endeavours. While the Tiger prototype flew nine months before the XF8U-1 Crusader (July 1954 vs March 1955), they were not delivered to the Navy’s development squadrons until February 1957 — three months after the first Crusader’s arrival.