"B" variant In 1990 the upgraded second production of the MiG-31 was put in service. It had an in-flight refueling probe, new radar, improved ECM and EW equipment and improved R-33S missiles as well as Long Range navigation facilities.
MIG-31B (1990s) : weapons similar to MIG-25 (R60, R40)
"BM" variant was approved in 2008 with 50 of the MiG-31Bs being modified to the BM ((Bolshaya Modernizatsiya/Deep Modernization) standards. The upgraded improved the detection range to 320 km (200 miles) and could track up to 10 targets and was increased to 24 targets capable of engaging 8 targets in newer releases. This variant could carry R-33S missiles and later R-37 anti-radar, air to ship and air to ground missiles. A multi-role aircraft with a refueling probe.
MIG-31BM (after2008) : same as “B” (adding rear mirror), use more modern weapons (R77, R33, R37)
"BSM" In 2014 a contract to upgrade 60 aircraft. The BSM variant has a refueling probe, New heat resistant glass for the canopy made it possible to fly faster and further, new rear-view periscope above the front cockpit canopy. New multi-function computers, new navigation systems. Multi-role capability can use anti-radar, anti-ship and air-to-ground missiles.
MIG-31BSM (after 2014) : hidden refueling probe, use more modern weapons (R77, R33, R37)
"K" This variant is capable of carrying the Kh-17M2 Kinzhal ALBM. By 2018 10 aircraft were modified to this variant.
MIG-31K : same as BM, carries Kh-17M2
General specifications for the MiG-31 “Foxhound”
First flight – September 16, 1975
Serial production began – 1979
Introduction into service – May 6, 1981
Role - long-range, two-seat supersonic interceptor aircraft
MiG-31K role – Supersonic attack
Crew – 2, Pilot and Weapons System Officer
Dimensions
Length – 22.62 m (74 ft 3 in)
Wingspan – 13.456 m (44 ft 2 in)
Height – 6.45 m 21 ft 2 in)
Weight
Empty – 21,820 kg (48,105 lb)
Gross – 41,000 kg (90, 390 lb)
Maximum takeoff – 46,200 kg (101,854 lb)
Performance
Powerplant – 2 X Soloviev D-30F6 afterburning turbofan engines each producing 93 kN (21,000 lbf) thrust dry, 152 kN (34,000 lbf) with afterburner
Speed
Maximum – 3,000 km/h (1,900 mph) Mach 2.83 @21,500 m (70,538 ft)
Cruise – 2,500 km/h (1,600 mph) Mach 2.35
Range – 3,000 km (1,900 mi) with 4 X R-33E and 2 drop tanks
Combat range – 1,450 km (900 mi) @ Mach 0.8 @ 10,000 m (32,808 ft)
Service ceiling – 25,000 m (82,000 ft)
Rate of climb – 288 m/s (56,700 ft/min)
Armament
Guns – 1 X 23 mm Gryazev-Shipunov GSh-23M rotary cannon 800 rounds (later removed)
Hardpoints
4 X semi-recessed under fuselage
4 X under wing pylons
These can carry
Missiles
Air-To-Air
4 X R-33E
2 X R-40RD/TD
4 X R-60MK
4 X R-73
Air-To-Surface
4 X Kh-58UShKE anti-radiation
1 X Kh-47M2 Kinzhal hypersonic air-launched ballistic missile (MiG-31K)