Origins

The origins of McDonnell’s F-4 can be traced to a 1953 request by the Navy for an upgrade of the McDonnell F3H Demon carrier-borne fighter. Although the Vought F8U Crusader won the contract, the "Super Demon" (as McDonnell’s entrant was dubbed) was developed as a ground attack aircraft under the designation AH, which by 1955 had evolved into an all-weather air superiority fighter designated F4H. The F4H first flew in 1958 and remained in production from 1959 until 1981. Dave Lewis was the chief of preliminary design and, ultimately, the program manager for development and the sales effort.

In 1952, McDonnell’s Chief of Aerodynamics, Dave Lewis, was appointed by CEO Jim McDonnell to be the company’s Preliminary Design Manager. With no new aircraft competitions on the horizon, internal studies concluded the Navy had the greatest need for a new and different aircraft type, an attack fighter. At the time, the Navy had separate fighter and attack branches, each with separate systems and operational requirements. After many iterations and various "enemy capability" assumptions, an unsolicited attack fighter was presented to the Navy. The McDonnell design called for two engines. The primary air-to-air armament was provided by the new Sparrow III air-to-air missiles, semi-recessed in the fuselage. The air-to-ground armament was to be as many bombs as could be carried on stations under the wings and aft of the Sparrows on the fuselage. No guns were offered. It took two years of hard work with the Bureau of Aeronautics and the Naval Air Warfare Division in the Pentagon, but the F-4 was sold with a configuration similar to what was originally proposed.

Super Demon

In 1953, McDonnell Aircraft began work on revising its F3H Demon naval fighter, seeking expanded capabilities and better performance. The company developed several projects including a variant powered by a Wright J67 engine, and variants powered by two Wright J65 engines, or two General Electric J79 engines. The J79-powered version promised a top speed of Mach 1.97. On 19 September 1953, McDonnell approached the United States Navy with a proposal for the "Super Demon". Uniquely, the aircraft was to be modular—it could be fitted with one- or two-seat noses for different missions, with different nose cones to accommodate radar, photo cameras, four 20 millimeter cannon, or 56 FFAR unguided rockets in addition to the nine hardpoints under the wings and the fuselage. The Navy was sufficiently interested to order a full-scale mock-up of the F3H-G/H but felt that the upcoming Grumman XF9F-9 and Vought XF8U-1 already satisfied the need for the supersonic fighter.

The McDonnell design was therefore reworked into an all-weather fighter-bomber with 11 external hardpoints for weapons and on 18 October 1954, the company received a letter of intent for two YAH-1 prototypes. On 26 May 1955, four Navy officers arrived at the McDonnell offices and, within an hour, presented the company with an entirely new set of requirements. Because the Navy already had the A-4 Skyhawk for ground attack and F-8 Crusader for dogfighting, the project now had to fulfill the need for an all-weather fleet defense interceptor. A second crewman was added to operate the powerful radar.

XF4H-1 prototype

The XF4H-1 was designed to carry four semi-recessed AAM-N-6 Sparrow III radar-guided missiles, and to be powered by two J79-GE-8 engines. As in the F-101 Voodoo, the engines sat low in the fuselage to maximize internal fuel capacity and ingested air through fixed geometry intakes. The thin-section wing had a leading edge sweep of 45 degrees and was equipped with a boundary layer control system for better low-speed handling.

Wind tunnel testing had revealed lateral instability requiring the addition of five degrees dihedral to the wings. To avoid redesigning the titanium central section of the aircraft, McDonnell engineers angled up only the outer portions of the wings by 12 degrees which averaged to the required five degrees over the entire wingspan. The wings also received the distinctive "dogtooth" for improved control at high angles of attack. The all-moving tailplane was given 23 degrees of anhedral to improve control at high angles of attack while still keeping the tailplane clear of the engine exhaust. In addition, air intakes were equipped with movable ramps to regulate airflow to the engines at supersonic speeds. All-weather intercept capability was achieved thanks to the AN/APQ-50 radar. To accommodate carrier operations, the landing gear was designed to withstand landings with a sink rate of 23 ft per second (7 m/s), while the nose strut could extend by some 20 inches (50 cm) to increase angle of attack at takeoff.

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