The AIM-9 Sidewinder (for Air Intercept Missile) is a heat-seeking air-to-air missile which first entered service with the United States Navy in 1956 and was adopted by the United States Air Force in 1964. Since then, the Sidewinder has proved to be an enduring international success, and its latest variants remain standard equipment in most western-aligned air forces. The SovietK-13 Vympel, a reverse-engineered copy of the AIM-9, was also widely adopted by a number of nations.
The Sidewinder is the most widely used air-to-air missile in the West, with more than 110,000 missiles produced for the U.S. and 27 other nations, of which perhaps one percent have been used in combat. It has been built under license by some other nations including Sweden, and can even be equipped by helicopters, such as the Bell AH-1Z Viper. The AIM-9 is one of the oldest, lowest cost, and most successful air-to-air missiles, with an estimated 270 aircraft kills in its history of use. When firing a Sidewinder, NATO pilots use the brevity code "FOX-2".
