Like the MiG-25, MiG-31 is a large twin-engine aircraft with side-mounted air intakes, a shoulder-mounted wing with an aspect ratio of 2.94, and twin vertical tailfins. Unlike the MiG-25, it has two seats, with the rear occupied by a dedicated weapon systems officer.
Airframe and engines
The wings and airframe of the MiG-31 are stronger than those of the MiG-25, permitting supersonic flight at low altitudes. Its Aviadvigatel D30-F6 turbofans, rated at 152 kN thrust, allow a maximum speed of Mach 1.23 at low altitude. High-altitude speed is temperature-redlined to Mach 2.83—the thrust-to-drag ratio is sufficient for speeds in excess of Mach 3, but such speeds pose unacceptable hazards to engine and airframe life in routine use.
Given the MiG-31's role as Mach 2.8+ interceptor and the sustained afterburning this requires, its fuel consumption is higher when compared to other aircraft serving in different roles, such as the Su-27. Consequently, the aircraft's fuel fraction has been increased to more than 0.40—16,350 kg (36,050 lb) of high-density T-6 jet fuel. The outer wing pylons are also plumbed for drop tanks, allowing an extra 5,000 L (1,320 US gal) of external fuel. Late-production aircraft have aerial refueling probes.
MiG-31 is limited to only 5 g at supersonic speeds. At combat weight, its wing loading is marginal and its thrust to weight ratio is favorable. However, it is not designed for close combat or rapid turning.
Electronics suite
The MiG-31 was the world's first operational fighter with a passive electronically scanned array radar (PESA), the Zaslon S-800. Its maximum range against fighter-sized targets is approximately 200 km (125 mi), and it can track up to 10 targets and simultaneously attack four of them with its AA-9 'Amos' missiles. It is claimed to have limited astern coverage, possibly due to drag chute housing above and between the engines. The radar is matched with an infrared search and tracking (IRST) system in a retractable undernose fairing.
MiG-31 was equipped with RK-RLDN and APD-518 digital secure datalinks. The RK-RLDN datalink is for communication with ground control centers. The APD-518 datalink enables a flight of four MiG-31 to automatically exchange radar-generated data within 200 km (124 mi) from each other. It also enables other aircraft with less sophisticated avionics, such as MiG-25, to be directed to targets spotted by MiG-31.
The MiG-31M-, MiG-31D-, and MiG-31BS-standard aircraft have an upgraded Zaslon-M radar, with larger antenna and greater detection range (said to be 400 km (250 mi) against AWACS-size targets) and the ability to attack multiple targets - air and ground - simultaneously. Zaslon-M have 1.4m diameter (larger) antenna, 50% to 100% better performance than Zaslon. In April 1994 used with an R-37 to hit a target at 300 km distance. Search range 400 km versus a 19/20 sq m RCS target. Tracks 24 targets at once, engages six. Supposedly able to engage launched Pershing-2 missiles in flight with long-range R-37 active radar-guided missiles. The back-seater's controls are replaced with modern multi-function displays. Its electronic countermeasures capabilities have also been upgraded, with new ECM pods on the wingtips.
Cockpit
The aircraft is a two-seater with the rear seat occupant controlling the radar. Although cockpit controls are duplicated across cockpits, it is normal for the aircraft to be flown only from the front seat. The pilot flies the aircraft by means of a centre stick and left hand throttles. The rear cockpit has only two small vision ports on the sides of the canopy. It is argued that the presence of the WSO (Weapon Systems Operator) in the rear cockpit improves aircraft effectiveness since the WSO is entirely dedicated to radar operations and weapons deployment. This decreases the workload of the pilot and increases efficiency. Both cockpits are fitted with zero/zero ejection seats which allow the crew to eject at any altitude and airspeed.
Some upgrade programmes have found their way to the MiG-31 fleet, for example the MiG-31BM multirole version which includes upgraded avionics. In the cockpit this upgrade provides capabilities of using of new weapons, a new multimode radar, HOTAS controls and liquid-crystal (LCD) colour multi-function displays (MFDs). Only a small part of the fleet, however, has been upgraded to this standard.
It has been claimed by Russian Federation Defence Ministry chief Colonel Yuri Balyko, that the upgrade will increase the combat effectiveness of the aircraft several times over.
Armament
The MiG-31's main armament is four R-33 air-to-air missiles (NATO codename AA-9 'Amos') carried under the belly. The R-33 is the Russian equivalent of the U.S. Navy's AIM-54 Phoenix. It can be guided in semi-active radar homing (SARH) mode, or launched in inertial guidance mode with the option of mid-course updates from the launch aircraft and switching to SARH for terminal guidance. A more advanced version of the weapon, the Vympel R-37, which is the replacement for the older R-33, features folding stabilizers to reduce its stored size.
Other weapons include the old AA-6 'Acrid', originally deployed on the MiG-25, and the Molniya R-60 or Vympel R-73 short-range IR missiles, carried on wing pylons. Currently the entire MiG-31 fleet is being refitted to carry the newer Vympel R-77 on the wing pylons.
General characteristics
- Crew: Two (pilot and weapons system officer)
- Length: 22.69 m (74 ft 5 in)
- Wingspan: 13.46 m (44 ft 2 in)
- Height: 6.15 m (20 ft 2 in)
- Wing area: 61.6 m² (663 ft²)
- Empty weight: 21,820 kg (48,100 lb)
- Loaded weight: 41,000 kg (90,400 lb)
- Max takeoff weight: 46,200 kg (101,900 lb)
- Powerplant: 2 × Soloviev D-30F6 afterburning turbofans
- Dry thrust: 93 kN (20,900 lbf) each
- Thrust with afterburner: 152 kN (34,172 lbf) each
Performance
- Maximum speed:
- High altitude: Mach 2.83 (3,000 km/h, 1,860 mph)
- Low altitude: Mach 1.2 (1,500 km/h, 930 mph)
- Combat radius: 720 km (450 mi) at Mach 2.35
- Ferry range: 3,300 km (2,050 mi)
- Service ceiling: 20,600 m (67,600 ft)
- Rate of climb: 208 m/s (41,000 ft/min)
- Wing loading: 665 kg/m² (136 lb/ft²)
- Thrust/weight: 0.85
- Maximum g-load: 5 g
Armament
- 1× GSh-6-23 23 mm cannon with 260 rounds.
- Fuselage recesses for 4× R-33 (AA-9 'Amos') (or for MiG-31M/BM only 6× R-37 (AA-X-13 'Arrow') long-range air-to-air missiles)
- 4 underwing pylons for a combination of:
- 2× R-40TD1 (AA-6 'Acrid') medium-range missiles, and
- 4× R-60 (AA-8 'Aphid')
- 4× R-73 (AA-11 'Archer') short-range IR missiles,
- 4× R-77 (AA-12 'Adder') medium-range missiles.
- Some aircraft are equipped to launch the Kh-31P (AS-17 'Krypton') and Kh-58 (AS-11 'Kilter') anti-radiation missiles in the suppression of enemy air defenses (SEAD) role.
