History of the F-15
During the mid-1960s the U.S. Air Force intelligence was shocked to find that the Soviet Union was building a large fighter aircraft, known as the MiG-25 "Foxbat". It was not known in the West at the time that the MiG-25 was designed as a high-speed interceptor, not an air superiority fighter; as such, its primary asset was speed, not maneuverability. The MiG-25's huge tailplanes and fins hinted at a very maneuverable aircraft, which worried the Air Force that its performance might be higher than its American counterparts. In reality, the MiG's large stabilizer and stabilators were necessary to prevent the aircraft from encountering inertia coupling in high-speed, high-altitude flight.
The F-4 Phantom II of the USAF and U.S. Navy was the only fighter with enough power, range and maneuverability to be given the primary task of dealing with the threat of Soviet fighters while flying with visual engagement rules. As a matter of policy, the Phantoms could not engage targets without positive visual identification, so they could not engage targets at long ranges as designed. Medium-range AIM-7 Sparrow missiles, and to a lesser degree even the AIM-9 Sidewinder, were often unreliable and ineffective at close ranges where it was found that guns were often the only effective weapon.
The Phantom did not originally have a gun, as it was intended that only missiles would be used to engage slowly moving and maneuvering Warsaw Pact bombers and fighters at longer ranges. Experience in Vietnam showed this not to be the case and led to the addition of a gun. At first an external gun pod was tried but that proved inaccurate and increased drag. Later, the 20 mm M61 Vulcan was integrated internally on the F-4E.
There was a clear need for a new fighter that overcame the close-range limitation of the Phantom while retaining long-range air superiority. After rejecting the U.S. Navy VFX program (which led to the F-14 Tomcat) as being unsuited to its needs, the U.S. Air Force issued its own requirements for the Fighter Experimental (F-X), a specification for a relatively lightweight air superiority fighter. Four companies submitted proposals, with the Air Force eliminating General Dynamics and selecting Fairchild Republic, North American Rockwell, and McDonnell Douglas for the definition phase in December 1968. The companies submitted technical proposals by June 1969. The Air Force announced the selection of McDonnell Douglas on 23 December 1969. The winning design resembled the twin-tailed F-14, but with fixed wings. It would not be significantly lighter or smaller than the F-4 that it would replace.
The Eagle's initial versions were designated F-15A for the single-seat configuration and F-15B for the twin-seat. These versions would be powered by new Pratt & Whitney F100 engines to achieve a combat thrust-to-weight ratio in excess of 1 to 1. A proposed 25 mm Ford-Philco GAU-7 cannon with caseless ammunition was dropped in favor of the standard M61 Vulcan gun due to development problems. The F-15 retained conformal carriage of four Sparrow missiles like the Phantom. The fixed wing was put onto a flat, wide fuselage that also provided an effective lifting surface. Some questioned if the zoom performance of the F-15 with Sparrow missiles was enough to deal with the new threat of the high-flying MiG-25 "Foxbat"; its capability would eventually be demonstrated in combat.
The first F-15A flight was made in July 1972 with the first flight of the two-seat F-15B (formerly TF-15A) following in July 1973.
The F-15 has a "look-down/shoot-down" radar that can distinguish low-flying moving targets from ground clutter. The F-15 would use computer technology with new controls and displays to lower pilot workload and require only one pilot to save weight. Unlike the F-14 or F-4, the F-15 has only a single canopy frame with clear vision forward. The USAF introduced the F-15 as "the first dedicated USAF air superiority fighter since the F-86 Sabre."
The F-15 would be favored by customers such as the Israel Air Force and Japan Air Self-Defense Force, and the development of the F-15E Strike Eagle would produce a strike fighter that would replace the F-111. However, criticism from the fighter mafia that the F-15 was too large to be a dedicated dogfighter, and too expensive to procure in large numbers to replace the F-4 and A-7, led to the Light Weight Fighter (LWF) program, which led to the USAF F-16 Fighting Falcon and the middle-weight Navy F/A-18 Hornet.
The single-seat F-15C and two-seat F-15D models entered production in 1978 with the models' first flights in February and June of that year. These new models have Production Eagle Package (PEP 2000) improvements, including 2,000 lb (900 kg) of additional internal fuel, provision for carrying exterior conformal fuel tanks and increased maximum takeoff weight of up to 68,000 lb (30,700 kg).