The Vympel R-33 was developed to be the main weapon of the Mikoyan MiG-31 Interceptor. The missile was developed by Vympel (Russian: Вымпел) in the 1960´s. The semi-active radar guided missile with inertial navigation to attack targets at great distances has many similarities to the already retired American-made AIM-54 Phoenix. The R-33 is actually not useable against highly manoeuvrable fighters, while it was designed to be used by the MiG-31 Interceptor against bombers, which are not very manoeuvrable. Primarily used on the MiG-31, both versions of the R-33 are an option for the Su-27.