The Vympel K-13 is a Soviet infrared-homing air-to-air missile, one of the first of its kind in the Soviet Union's arsenal. During the Second Taiwan Strait Crisis, in 1958, a PLAAF fighter was hit by an American AIM-9 "Sidewinder" which did not detonate. This almost intact weapon was sent to Moscow, where the design was duplicated and mass-produced for use by both air forces, becoming the K-13. So close is the reverse-engineering that AIM-9 components are compatible with the K-13 and vice-versa. Its effective range is of 3.5km, limited by lock-on distance