Vympel R-33

R-33 AA-9 Amos
R-33 on MiG-31 at Zhukovski, 1999
Type	Heavy air-to-air missile
Specifications
Weight	490 kg (1,080 lb)
Length	4.14 m (13 ft 7 in)
Diameter	380 mm (15 in)
Warhead	47.5 kg (105 lb)
Wingspan	1.12 m (3 ft 8 in)
Operational range	120 km (1981), 160 km (1999), 304 km (2012).
Speed	Mach 4.5 - 6 (R-37)
Guidance system	inertial and semi-active radar homing; terminal active radar homing (R-33E)

The R-33 (Russian: Вымпел Р-33, NATO reporting name: AA-9 Amos) is a long-range air-to-air missile developed by the Vympel. It is the primary armament of the MiG-31 interceptor, intended to attack large high-speed targets such as the SR-71 Blackbird, the B-1 Lancer bomber, and the B-52 Stratofortress.

Generally similar to the U.S. Navy's AIM-54 Phoenix, it uses a combination of semi-active radar homing for initial acquisition and mid-course updates, and inertial navigation to reach the target at extreme range. The Zaslon phased array radar of MiG-31 allows four missiles to be guided simultaneously at separate targets.

The R-33 AAM remains in service with the CIS and Russian forces (See MiG-31 operators).

The history of the R-33 missile is tightly bound to the story of its launcher, the MiG-31. The development of the modernized MiG-25, E-155MP, was authorized by a governmental decision of 24 May 1968. There was a competition for future missiles for the E-155MP. Izdeliye 410 by "Vympel" of A.L.Lyapin won, while the K-50 by PKPK of M.R.Bisnovat lost. The missile was assigned the development name K-33, continuing the series of K-13 and K-23 missiles. The development was headed by vice-chief designer V.V.Zhuravlev and leading designer Y.K.Zakharov.

The R-33/MiG-31 missile/interceptor combination is similar to the earlier Bisnovat R-40/MiG-25 combination, although it is much more versatile and modern in that the MiG-25 was very heavily specialized for the interception of large supersonic targets such as the cancelled North American Aviation XB-70 bomber, and thus lacks maneuverability and is not suitable for air combat maneuvering. The MiG-31 is a much more versatile and capable aircraft and is still able to employ the older R-40.