Design and Development

Origins

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.

Cockpit of F-4 Phantom II

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 mm (.79 in) 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° 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 5° 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°, which averaged to the required 5° 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° 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/s (7 m/s), while the nose strut could extend by some 20 in (50 cm) to increase angle of attack at takeoff.

Naming the aircraft

There were proposals to name the F4H "Satan" and "Mithras", the Persian god of light. In the end, the aircraft was given the less controversial name "Phantom II", the first "Phantom" being another McDonnell jet fighter, the FH-1 Phantom. The Phantom II was briefly given the designation F-110A and the name "Spectre" by the USAF, but neither title was used.

Prototype testing

On 25 July 1955, the Navy ordered two XF4H-1 test aircraft and five YF4H-1 pre-production fighters. The Phantom made its maiden flight on 27 May 1958 with Robert C. Little at the controls. A hydraulic problem precluded retraction of the landing gear but subsequent flights went more smoothly. Early testing resulted in redesign of the air intakes, including the distinctive addition of 12,500 bleed air holes on each ramp; and the aircraft soon squared off against the XF8U-3 Crusader III. Due to operator workload, the Navy wanted a two-seat aircraft and on 17 December 1958 the F4H was declared a winner. Delays with the J79-GE-8 engines meant that the first production aircraft were fitted with J79-GE-2 and -2A engines, each having 16,100 lbf (71.8 kN) of afterburning thrust. In 1959, the Phantom began carrier suitability trials with the first complete launch-recovery cycle performed on 15 February 1960 from USS Independence.

A flight of USAF F-4Cs refuel from a KC-135 tanker before making a strike against targets in North Vietnam. The Phantoms are fully loaded with 750-pound general purpose bombs, Sparrow missiles and external fuel tanks.

Production

Early in production, the radar was upgraded to a larger AN/APQ-72, necessitating the bulbous nose, and the canopy was reworked to improve visibility and make the rear cockpit less claustrophobic. The Phantom underwent a great many changes during its career, summarized in the "Variants" section below.

The USAF received Phantoms as the result of Defense Secretary Robert McNamara's push to create a unified fighter for all branches of the military. After an F-4B won the "Operation Highspeed" fly-off against the F-106 Delta Dart, the USAF borrowed two Naval F-4Bs, temporarily designating them F-110A "Spectre" in January 1962, and developed requirements for their own version. Unlike the Navy focus on interception, the USAF emphasized a fighter-bomber role. With McNamara's unification of designations on 18 September 1962, the Phantom became the F-4 with the Naval version designated F-4B and USAF F-4C. The first Air Force Phantom flew on 27 May 1963, exceeding Mach 2 on its maiden flight.

Phantom II production ended in the United States in 1979 after 5,195 had been built (5,057 by McDonnell Douglas and 138 in Japan by Mitsubishi), making it the second-most produced and exported American military-jet after the F-86 Sabre. Of these, 2,874 went to the USAF, 1,264 to the Navy and Marine Corps, and the rest to foreign customers. The last U.S.-built F-4 went to Turkey, while the last F-4 ever built was completed in 1981 as an F-4EJ by Mitsubishi Heavy Industries in Japan. As of 2008, 631 Phantoms remained in active service worldwide, while the Phantom also remains in use as a drone operated by the U.S. military.

World records

To show off their new fighter, the Navy led a series of record-breaking flights early in Phantom development:

  • Operation Top Flight: On 6 December 1959, the second XF4H-1 performed a zoom climb to a world record 98,557 ft (30,040 m). The previous record of 94,658 ft (28,852 m) was set by a Soviet Sukhoi T-43-1 prototype. Commander Lawrence E. Flint, Jr., USN accelerated his aircraft to Mach 2.5 at 47,000 ft (14,330 m) and climbed to 90,000 ft (27,430 m) at a 45° angle. He then shut down the engines and glided to the peak altitude. As the aircraft fell through 70,000 ft (21,300 m), Flint restarted the engines and resumed normal flight.
  • On 5 September 1960, an F4H-1 averaged 1,216.78 mph (1,958.16 km/h) over a 500 km (311 mi) closed-circuit course.
  • On 25 September 1960, an F4H-1 averaged 1,390.21 mph (2,237.26 km/h) over a 100 km (62 mi) closed-circuit course.
  • Operation LANA: To celebrate the 50th anniversary of Naval aviation (L is the Roman numeral for 50 and ANA stood for Anniversary of Naval Aviation) on 24 May 1961, Phantoms flew across the continental United States in under three hours and included several tanker refuelings. The fastest of the aircraft averaged 869.74 mph (1,400.28 km/h) and completed the trip in 2 hours 47 minutes, earning the pilot (and future NASA Astronaut), Lieutenant Richard Gordon, USN and RIO, Lieutenant Bobbie Long, USN, the 1961 Bendix trophy.
  • Operation Sageburner: On 28 August 1961, a Phantom averaged 902.769 mph (1,452.826 km/h) over a 3 mi (4.82 km) course flying below 125 ft (40 m) at all times. Commander J.L. Felsman, USN was killed during the first attempt at this record on 18 May 1961 when his aircraft disintegrated in the air after pitch damper failure.
  • Operation Skyburner: On 22 December 1961, a modified Phantom with water injection set an absolute world record speed of 1,606.342 mph (2,585.086 km/h).
  • On 5 December 1961, another Phantom set a sustained altitude record of 66,443.8 ft (20,252.1 m).
  • Operation High Jump: A series of time-to-altitude records was set in early 1962; 34.523 seconds to 3,000 m (9,840 ft), 48.787 seconds to 6,000 m (19,680 ft), 61.629 seconds to 9,000 m (29,530 ft), 77.156 seconds to 12,000 m (39,370 ft), 114.548 seconds to 15,000 m (49,210 ft), 178.5 seconds to 20,000 m (65,600 ft), 230.44 seconds to 25,000 m (82,000 ft), and 371.43 seconds to 30,000 m (98,400 ft). Although not officially recognized, the Phantom zoom-climbed to over 100,000 ft (30,480 m) during the last attempt.

All in all, the Phantom set 16 world records. With the exception of Skyburner, all records were achieved in unmodified production aircraft. Five of the speed records remained unbeaten until the F-15 Eagle appeared in 1975.

Flight characteristics

In air combat, the Phantom's greatest advantage was its thrust, which permitted a skilled pilot to engage and disengage from the fight at will. The massive aircraft, designed to fire radar-guided missiles from beyond visual range, lacked the agility of its Soviet opponents and was subject to adverse yaw during hard maneuvering. Although thus subject to irrecoverable spins during aileron rolls, pilots reported the aircraft to be very communicative and easy to fly on the edge of its performance envelope. In 1972, the F-4E model was upgraded with leading edge slats on the wing, greatly improving high-angle-of-attack maneuverability at the expense of top speed.

The J79 engines produced copious amounts of black smoke at military power which made the Phantoms easy to spot from a distance, a severe disadvantage in air combat against smaller aircraft. Pilots could eliminate the smoke by using afterburner, but at the cost of fuel efficiency. Some pilots adopted the procedure of running one engine in dry thrust at normal power setting, and the other in afterburner, resulting in the same total thrust as using both engines at full rated military power without generating the tell-tale smoke trail.

The F-4's biggest weakness, as it was initially designed, was its lack of an internal cannon. For a brief period, doctrine held that turning combat would be impossible at supersonic speeds and little effort was made to teach pilots air combat maneuvering. In reality, engagements quickly became subsonic. Furthermore, the relatively new heat-seeking and radar-guided missiles at the time were frequently reported as unreliable and pilots had to use multiple shots just to hit one target. To compound the problem, rules of engagement in Vietnam precluded long-range missile attacks in most instances, as visual identification was normally required. Many pilots found themselves on the tail of an enemy aircraft but too close to fire short-range Falcons or Sidewinders. Although in 1967 USAF F-4Cs began carrying SUU-16 or SUU-23 external gunpods containing a 20 mm (.79 in) M61 Vulcan Gatling cannon, USAF cockpits were not equipped with lead-computing gunsights, virtually assuring a miss in a maneuvering fight. Some Marine Corps aircraft carried two pods for strafing. In addition to the loss of performance due to drag, combat showed the externally mounted cannon to be inaccurate unless frequently boresighted, yet far more cost-effective than missiles. The lack of cannon was finally addressed by adding an internally mounted 20 mm (.79 in) M61 Vulcan on the F-4E.