Mikoyan MiG-31


The Mikoyan MiG-31 is a supersonic interceptor aircraft developed for the Soviet Air Forces by the Mikoyan design bureau as a replacement for the MiG-25 "Foxbat", on which it is based and shares design elements.
The MiG-31 is the fastest known operational combat aircraft, with a top speed around. It continues to be operated by the Russian Aerospace Forces following the end of the Cold War and the collapse of the Soviet Union in 1991. The other operator, the Kazakh Air Defence Forces, retired the type in 2023. The Russian Defence Ministry expects the MiG-31 to remain in service until at least 2030; that was confirmed in 2020 when an announcement was made to extend the service lifetime of the existing airframes from 2,500 to 3,500 hours. The MiG-31K variant carries the Kh-47M2 Kinzhal conventional or nuclear warhead-capable air-launched ballistic missile.

Development

Background

The single-seat MiG-25 could achieve high speed, altitude, and rate of climb, but it lacked manoeuvrability at interception speeds and was difficult to fly at low altitudes. The MiG-25's speed was normally limited to Mach 2.83, but it could reach a maximum speed of at least Mach 3.2 with the risk of engine damage.
Development of the MiG-25's replacement began with the Ye-155MP prototype, which first flew on 16 September 1975. Although it bore a superficial resemblance to the MiG-25, it had a longer fuselage to accommodate the radar operator's cockpit, and was in many respects a new design. An important development was the MiG-31's advanced radar, capable of both look-up and look-down/shoot-down engagement, as well as multiple target tracking. This gave the Soviet Union an interceptor with the capability to engage the most likely Western intruders at long range. The MiG-31 replaced the Tu-128 as the Soviet Union's dedicated long-range interceptor, with far more advanced sensors and weapons, while its range is almost double that of the MiG-25.
Like that of its MiG-25 predecessor, the introduction of the MiG-31 was surrounded by early speculation and misinformation concerning its design and abilities. The West learned of the new interceptor from Lieutenant Viktor Belenko, a pilot who defected to Japan in 1976 with his MiG-25P. Belenko described an upcoming "Super Foxbat" with two seats and an ability to intercept cruise missiles. According to his testimony, the new interceptor was to have air intakes similar to the Mikoyan-Gurevich MiG-23, which the MiG-31 does not have, at least in production variants.

Production

Serial production of the MiG-31 began in 1979. The first production batch of 519 MiG-31s including 349 "baseline models" was produced at the Sokol plant between 1976 and 1988. The second batch of 101 MiG-31DZs was produced from 1989 to 1991. The final batch of 69 MiG-31B aircraft was produced between 1990 and 1994. From the final batch, 50 were retained by the Kazakhstan Air Force after the dissolution of the Soviet Union. Of the "baseline models", 40 airframes were upgraded to MiG-31BS standard.

Upgrades and replacement

Some upgrade programs have found their way into the MiG-31 fleet, such as the MiG-31BM multirole version with upgraded avionics, new multimode radar, hands-on-throttle-and-stick controls, liquid crystal colour multifunction displays, ability to carry the R-77 missile and various Russian air-to-ground missiles such as the Kh-31 anti-radiation missile, a new and more powerful computer, and digital data links. A project to upgrade the Russian MiG-31 fleet to the MiG-31BM standard began in 2010; 100 aircraft were to be upgraded to the MiG-31BM standard by 2020. Russian Federation Defence Ministry chief Colonel Yuri Balyko has claimed that the upgrade would increase the combat effectiveness of the aircraft several times over. 18 MIG-31BMs were delivered in 2014. The Russian military was to receive more than 130 upgraded MiG-31BMs, with the first 24 aircraft already delivered according to Russian Deputy Defence Minister Yuri Borisov in his press briefing on 9 April 2015.
Russia planned to start development of a replacement for the MiG-31 by 2019. The aircraft would be called PAK-DP. Development of the new aircraft, designated MiG-41, began in April 2013. Such development is favored over restarting MiG-31 production. In March 2014, Russian test pilot Anatoly Kvochur said that work began on a Mach 4 capable MiG-41 based on the MiG-31. Later reports stated that the development of the MiG-31 replacement was to begin in 2017, with the first aircraft expected to be delivered in 2020, and the replacement entering service in 2025.This has currently yet to happen.

Design

Like the MiG-25, the MiG-31 is a large twin-engined aircraft with side-mounted air intake ramps, 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.
The MiG-31 was designed to fulfill these mission objectives:
  • Intercept cruise missiles and their launch aircraft by reaching missile launch range in the shortest possible time after departing the loiter area
  • Detect and destroy low flying cruise missiles, UAVs and helicopters
  • Long-range escort of strategic bombers
  • Provide strategic air defense in areas not covered by ground-based air defense systems
The MiG-31 is limited to five g when travelling at supersonic speeds. While flying under combat weight, its wing loading is marginal and its thrust-to-weight ratio is favorable. The MiG-31 is not designed for close combat or rapid turning.
The wings and airframe of the MiG-31 are stronger than those of the MiG-25, permitting supersonic flight at low altitudes. Like the MiG-25, its flight surfaces are built primarily of nickel-steel alloy, enabling the aircraft to tolerate kinetic heating at airspeeds approaching Mach 3. The MiG-31 airframe comprises 49% arc-welded nickel steel, 33% light metal alloy, 16% titanium, and 2% composites. Its D30-F6 jet engines, each 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.

Electronics suite

The MiG-31 was among the first aircraft with a phased-array radar. Its maximum range against fighter-sized targets is about, and it can track up to 10 targets and simultaneously attack four of them with its Vympel R-33 missiles. The radar is matched with an infrared search and track system in a retractable under-nose fairing.
The aircraft 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-31s to automatically exchange radar-generated data within of each other. It also enables other aircraft with less sophisticated avionics, such as MiG-23s, 25s, and 29s and Su-15s and 27s, to be directed to targets spotted by MiG-31. The A-50 AEW aircraft and MiG-31 can automatically exchange aerial and terrestrial radar target designation, as well as air defense. The MiG-31 is equipped with ECM of radar and infrared ranges.
The flight-navigation equipment of the MiG-31 includes a complex of automatic control system SAU-155МP and sighting-navigation complex KN-25 with two inertial systems and IP-1-72A with digital computer, electronic long-range navigation system Radical NP or A-331, electronic system of the long-range navigation A-723. Distant radio navigation is carried out by means of two systems: Chayka and «Route».
Similarly to the complex S-300 missile system, aircraft group with APD-518 can share data obtained by various radars from different directions and summarize the data. The target can be detected passively and/or actively simultaneously from many different directions. Every aircraft with the APD-518 will have the exact data, even if it is not involved in the search.
  • interacting with ground-based automated digital control system, operating modes of remote aiming, semiautomated actions, singly, and also to direct on the target missiles launched from the other aircraft.
  • Digital immune system provides the automatic exchange of tactical information in a group of four interceptors, remote one from another at a distance of and aiming at the target group of fighters with less-powerful avionics.
A group of four MiG-31 interceptors is able to control an area of air space across a total length of ; its radar possessing a maximum detection range of in distance and the typical width of detection along the front of.

Radars

Adopted in 1981, RP-31 N007 backstop.
  • the range of detection of air targets with Zaslon-A:
  • target detection distance with radar cross-section of in the rear within with a probability of 0.5
  • number of detected targets: 24
  • number of targets for attack: 6
  • range of automatic tracking:
  • detection of infrared signature targets:
  • Effective in the detection of cruise missiles and other targets against ground clutter
  • Until 2000, it was the world's only fighter in service equipped with phased array radar, when the Mitsubishi F-2 entered service with the J/APG-1 active phased array radar.
  • Able to intercept and destroy cruise missiles flying at extremely low altitudes.

    Variant differences

The basic differences between other versions and the MiG-31BM are:
  • The onboard radar complex of the MiG-31BM can track 24 airborne targets at one time, six of which can be simultaneously attacked by R-33S missiles.
  • Modernized variants of the aircraft can be equipped with anti-radiation missiles Kh-31, Kh-25MR or MPU, anti-ship Kh-31A, air-to-surface class missiles Kh-29 and Kh-59 or Kh-59M, up to six precision bombs KAB-1500 or eight KAB-500 with television or laser-guidance. Maximum mass of payload is.
  • The MiG-31M, MiG-31D, and MiG-31BM standard aircraft have an upgraded Zaslon-M radar, with larger antenna and greater detection range and the ability to attack multiple targets – air and ground – simultaneously. The Zaslon-M has a diameter antenna, with 50–100% better performance than Zaslon. In April 1994 it was used with an R-37 to hit a target at distance. It has a search range of for a RCS target and can track 24 targets at once, engaging six, or for. Relative target speed detection increased from Mach 5 to Mach 6, improving the probability of destroying fast-moving targets. The MiG-31BM is one of only a few Soviet aircraft able to intercept and destroy cruise missiles flying at extremely low altitude.