The MiG-25 was designed to counter high-flying threats. The MiG-31 was the result of the demand to counter low-level threats, such as the B-1B and cruise missiles. Development began in 1967 and the S-155MP avionics complex was ordered for the Ye-155MP interceptor in 1968.
The Ye-155MP '831' was a converted Type 83 MiG-25MP, serving as the prototype of the design, and first flew on 16 September 1975. The second prototype ('832'), with radar, first flew 22 April 1976.
Designed as a long-range, extended-endurance PVO interceptor to replace the Tu-128 and MiG-25 based on the MiG-25 many changes were necessary to improve range and flight performance at low altitude. The fuselage was strengthened to make it suitable for supersonic flight at low level. The 'Foxhound' is powered by two D-30F6 turbofans which improved range drastically over the MiG-25 engines. The D-30F6 needed larger air intakes and larger exhaust nozzles. The key to success of the MiG-31 as an interceptor is the Zaslon SBI-16 phased array radar. This fire control radar is capable of tracking 10 targets at ranges up to 120 kilometers (75 miles) and engage four targets at once. Tracking and engagement is the task of the WSO which is seated behind the pilot. It is armed with four long-range R-33 (AA-9 Amos) air-to-air missiles carried under the fuselage.
Two preproduction aircraft (011 and 012) built by Sokol and flown 13 July and 30 June 1977, followed by six development aircraft (201 to 203 and 301 to 303).
Full production (of about 450) started 1979 and in 1982 the NATO reporting name 'Foxhound' was made public. The first of 11 regiments were operational by 1983, replacing MiG-23 and Su-15 in the air defence role.
By 1987 over 150 MiG-31s were deployed across the Soviet Union, especially in the west and far east.
The MiG-31B incorporated an improved Zaslon-A fire control radar, superior long-range missiles (R-33S), additional missiles (the R-40TD medium-range missiles and R-60 short-range missiles), modernised navigation computer and new data exchange modes. The MiG-31B was also equipped with in-flight refuelling system, whereas the MiG-31BS designation was used for MiG-31B upgrades lacking this ability.
The MiG-31D was a specialised variant for the Russian equivalent of the ASAT program, carrying a single anti-satellite missile. It can be recognized by the big vertical fins at the wing tips.
In 1992 the MiG-31E (export) was first presented on the Berlin Air Show ILA. Only one aircraft was built.
The MiG-31FE was a proposed multipurpose variant of the MiG-31 with improved weapons systems and avionics. It is able to operate the majority of the Russian air-to-surface missiles. Laser and TV equipment for missile guidance would have been accommodated in an external pod. Intended for export, it did not receive any orders.
The MiG-31M is a highly improved version of the original MiG-31. It has new IRST and phased-array radar to engage six targets at the same time. It is capable of carrying the R-37, which is an improved version of the R-33 AAM. And it is also capable of carrying the R-77 (AA-12 Adder), instead of the R-40TD, which was used on the MiG-31B. The cockpit was redesigned and features three colour multi function displays. Other changes include larger fuel capacity, no gun, uprated engines, aerodynamic improvements, larger brake chute housing, redesigned nosewheel. Six prototypes were built but none were ordered.
The MiG-31BM is an upgraded MiG-31B which adds an air-to-surface capability. New onboard computer systems and a new fire control radar capable of tracking up to 24 targets simultaneously.
In 2003 a MiG-31 claimed a 100 km closed circuit speed world record of 840 kts, a time to climb to 66,550 ft world record of 8 min 23 sec and an absolute altitude world record of 72,175 ft.
Kazakhstan inherited around 30 MiG-31 Foxhounds after the break up of the Soviet Union. Some of these aircraft remained in operational service.
Reportedly a contract with China was signed in 1992 for 24 MiG-31 interceptors. The plan included a newly set-up factory in Shenyang and were expected to enter service in 2000. At some point it was expected that at least 200 MiG-31s would be deployed by 2010. The contract was either cancelled or was never signed. Instead China opted for the Su-27/30 Flanker (J-11) as their long range interceptor.
Engines: 2 x D-30F6, 151.9kN
Max take-off weight: 41000-46000 kg / 90390 - 101413 lb
Empty weight: 29120 kg / 64199 lb
Wingspan: 13.5 m / 44 ft 3 in
Length: 22.7 m / 74 ft 6 in
Height: 6.2 m / 20 ft 4 in
Wing area: 61.6 sq.m / 663.06 sq ft
Max. speed: 3000 km/h / 1864 mph
Cruise speed: 2500 km/h / 1553 mph
Ceiling: 20000 m / 65600 ft
Range w/max.fuel: 3000 km / 1864 miles
Range w/max.payload: 1200 km / 746 miles
Armament: 1 x 23mm cannon, 8 missiles
Mikoyan Gurevich MiG 31
Fighter Interceptor and Reconnaissance, Russia, 1976
Engine : 2 Klimov R 31 F, 134691 N / 13730 kp
Length : 68.898 ft / 21.0 m
Height : 18.373 ft / 5.6 m
Wingspan : 45.604 ft / 13.9 m
Wing area : 602.784 sqft / 56.0 sq.m
Max take off weight : 77175.0 lb / 35000.0 kg
Weight empty : 46812.2 lb / 21230.0 kg
Max. payload weight : 30362.9 lb / 13770.0 kg
Max. speed : 1320 kts / 2445 km/h
Service ceiling : 80052 ft / 24400 m
Wing load : 128.13 lb/sq.ft / 625.0 kg/sq.m
Range : 1026 nm / 1900 km
Crew : 2
Hardpoints: 4 under fuselage, 4 under wing.
Powerplant: two 151.9 kN (34,170 lb st) Aviadvigatel D-30F6 afterburning turbofans
Length 22.69m (74 ft 5¼ in)
Height 6.15m (20 ft 2¼ in)
Wing span 13.46m (44ft 2 in)
Empty weight 21.825 kg (48,115 lb)
Max Take-Off Weight 46.200 kg (101,850 lb)
Max level speed at 17,500 m (57,400 ft) more than Mach 2.8 or 3.000 km/h (1,865 mph)
Service ceiling 20,600m (67,600 ft)
Armament: one 23mm GSh-6-23 six-barrel gun / 260 rounds; eight air-to-air missiles (4 R-33 and 4 R-60 AAMs, or 3 R-33 and 2 R-40TD AAMs)
Top speed: M2.83