The Vought F-8E Crusader was more affectionately known as “The Last Gunfighter,” showing the innovative spirit of mid-20th-century military aviation. A single-engine, carrier-based jet fighter, that received the designation F8U-2NE, it was a definitive production variant of the Crusader series. It featured a variable-incidence wing: during takeoff and landing, the whole wing was extended out of the fuselage by 7 degrees to improve lift at low speeds. This design, featuring leading-edge slats, an area-ruled fuselage, an all-moving stabilator, and dog-tooth wings, provided increased yaw stability. The F-8E was armed with four 20mm cannons, marking it as the last US fighter designed around gun armament as the primary weapon.
First flying on March 25, 1955, the F-8E became available to its first operational unit, VX-3 in late 1956. With the improved APQ-94 radar thus providing all-weather capability, the F-8E was quite an improvement over the day-fighter predecessors of the aircraft. This variant also provided enhanced air-to-ground capability, essential when this variant served in Vietnam. Carrier trials of the F-8E had taken place in 1963, and production ended in mid-1964. Vought continued to develop the aircraft, upgrading the F-8E to the F-8J with an even more powerful engine, wet pylons, and new radar. Foreign militaries that used the Crusader included the French Aéronavale.
The performance of the F-8E included a maximum speed of 584 knots at 10,000 feet with military thrust, a combat ceiling of 52,350 feet, and a Pratt & Whitney J57-P-20 engine driven by 18,000 lbf with afterburner power. Armament: four Colt Mk.12 Mod 3 20mm cannons, plus various bombs, rockets, and missiles, including AIM-9B Sidewinders and Zuni AGMs.
Besides this development, transitioning to the A-7D Corsair II led the Air Force to search for a more advanced engine than the Pratt & Whitney TF-30 used on the Navy’s A-7. Increased takeoff thrust and higher production line rates were the main features advancing the choice of engines between the Rolls Royce Spey and augmented development by the Allison Division of General Motors and Rolls Royce, Ltd. The Spey engine, designated the Allison TF-41, gave 14,250 pounds of dry thrust compared to the TF-30’s 10,950 pounds. Such an option favored not only in cost and availability but also in production rate, which was earlier and quicker.
The A-7D was planned to fly in mid-1968; it was set to bring current forces in the mission of close air support and interdiction and eventually phase out F-100 and F-105. It sought to adopt the TF41-A-1 Spey turbofan engine, which developed something on the order of 14,500 pounds of maximum thrust, to respond to the restrictions the Navy had imposed on its A-7A/A-7B Corsairs because of limitations imposed on the TF30 engines. Problems of this nature were already recognized as limiting the desirability of runway takeoffs of combat-loaded aircraft in Southeast Asia.
For sure, the wing of the A-7D was fixed, in contrast to the variable-incidence wing of the F-8 Crusader. This allied to a major decrease in size and wing sweepback, was lamented by some parties who reportedly claimed that a relatively small amount of money could have seen the development of a supersonic airframe. Indeed, the A-7D was quite adequate in its subsonic specifications for the niche roles that it was designed to fill at the time in the ongoing evolution of military aviation requirements and accompanying strategies.