A long-range supersonic interceptor and AWACS aircraft produced by Mikoyan Gurevich for the Soviet Union during the early 1980s; the sequel to the MiG-25 Foxbat. It has a similar objective to the MiG-25 - interception of supersonic targets such as the SR-71 Blackbird, cruise missiles or bombers - but is also designed for low-altitude, high-speed intercepts and has improved abilities over its predecessor in that respect.
The MiG-25 was the reasonably solid foundation for the MiG-31. Although that aircraft remains the fastest interceptor ever (and is still the fastest operational military aircraft in the world) it had major problems of range, poor low-level performance and increasingly outdated weapon systems. As the West began to focus on low-level strike tactics during the 1960s(14) using aircraft like the F-111 Aardvark these weaknesses were highlighted, as was the fact the Soviet Union had no aircraft designed for supersonic, low-level intercepts.
When a disgruntled Soviet pilot named Viktor Belenko delivered a MiG-25 to the West in 1976 he reported that pilots were forbidden to exceed mach 2.5 in the MiG-25 and that they never flew more than 900km, vastly below the 2000km range Western intelligence believed them capable of. However Belenko also reported the existence of a "Super Foxbat" during his months-long debriefing by US intelligence: a two-seater version of the MiG-25 with a strengthened airframe for low-level supersonic flight and a much more sophisticated radar.
Certain details of the Foxbat's performance remain unknown and probably classified (the aircraft was never flown by the West - it was analysed, taxied at speed a few times and returned to the Soviet Union a couple of weeks after the defection), but it seems likely the MiG-31 was developed to address problems with the MiG-25, as increased range and low-level performance were areas of particular focus during the aircraft's development.
Production & History
The MiG-31 was designed in parallel with late variants of the MiG-25. Designs thrown around in the early stages included a swing-wing aircraft like the F-111 or British Tornado, and even a tailless design with delta wings and canards like the Eurofighter Typhoon and Sukhoi Su-35. What eventually emerged as the MiG-31 was originally designated MiG-25MP, a heavily modified MiG-25. Plans were even made to use the MiG-25 as a testbed for the engines that would be used in the MiG-31 before work on the Foxbat line was dropped altogether.
Two prototypes were produced, designated Ye-155MP, the first flying in September 1976 and the second the following May. MiG's factory at Gorky manufactured eight preproduction aircraft in 1977 and several years of trials followed. As may be expected several of the preproduction aircraft crashed during trials, one of which resulted in the death of Mikoyan's star test pilot Alexander Fedotov (who flew the MiG-25s that set all of the type's speed and altitude records). Following some improvements to the airframe and aircraft systems, full production was authorised in 1981 and about 450 aircraft were built over the years following. The first regiment was operational in 1983, replacing MiG-15s and MiG-23s. Eleven regiments were operational at peak. Production is currently halted but the Sokol plant, which manufactured all aircraft, has stated it is willing to restart production even for small orders. Buy now while stocks last.
The West did not get a good look at the MiG-31 until 1985 when a Norwegian fighter intercepted one over the Barents Sea and the pilot took photographs (I'm guessing most of the publicly-available black & white photographs of the MiG-31 in flight were taken during this intercept). It seems this was a photo opportunity, the Soviets supposedly having long used this method to introduce new aircraft to the West; the MiG promptly went home afterwards(14). The next good opportunity for the West to see the MiG-31 was at the 1991 Paris airshow, where the Soviets surprised many by removing the radome from the aircraft, allowing people to see the radar receiver.
The initial version of the Foxhound was manufactured through to about 1985 and somewhere from 450 to 500 were built in total; an unclear number of these are currently in service with the Russian Air Force, which inherited them from the Soviet homeland defence force (PVO) after the breakup of the Soviet Union. Kazakhstan also inherited about 30 of them but these are reportedly not in flying condition.
Design & Layout
The MiG-31 looks similar to the MiG-25 but any more than a cursory glance reveals many differences. The plan of both aircraft is more or less the same but the MiG-31 is a bit less rough around the edges and more heavy-set than its older brother; a much more sophisticated and capable aircraft in a familiar shell. It's easy to believe mllwswpr's assertions of the MiG-31's weight in his writeup above, as the aircraft dwarfs every fighter and interceptor I've ever seen. Although about one metre shorter than the Foxbat, it sits much higher on its undercarriage and is over six metres tall at the tips of its twin tail fins, almost two metres taller than the average semitruck trailer. It is gigantic:
http://www.b-domke.de/AviationImages/Foxhound/Images/2043.jpg (Eeep! Look at the man standing next to it!)
In another of my fake walk-arounds, the height of the aircraft is the first thing to make an impression. My head doesn't even touch the underneath of the fuselage when I'm standing up underneath it. Walking back underneath the fuselage (shaped so that it contributes lift) from the twin airbrakes mounted under the air intakes, one can see the unusual missile mountings. Instead of the common launching method of releasing a missile and only igniting its rocket motor after it is clear of the aircraft, a fuselage-mounted missile on a foxhound swings down on a hydraulically-actuated trapeze arrangement to launch. This assembly retracts into the fuselage afterwards.
Further back we can see the curious arrangement of the wheels on the main undercarriage, about halfway down the fuselage: they are in a staggered tandem configuration - one wheel in front of the other - but the rear wheel is offset from the one in front. This is for poor quality or unprepared runways or taxiways so the rear wheel does not sink into the rut created by the front one, important for such a heavy aircraft.
Walking to the rear of the aircraft, underneath the housing for the braking parachute between the twin tailpipes, one can see they are not quite as large in diameter as those of the MiG-25, though they are much longer and do taper slightly. They reach back behind the all-moving tailplanes which are mounted further forward on the fuselage. Above these are the tall, swept-back outward-canted vertical stabilizers. Walking around the side of the aircraft shows the large wing root extensions, larger than those on the Foxbat. The wings are rounded at the corners but have more or less the same shape as the Foxbat's, each with four weapon pylons.
The MiG-31 is constructed from a similar spread of materials as the MiG-25 but with a different distribution. 80% of the MiG-25 was made of nickel steel due to the Soviet Union's rather limited titanium manufacturing capabilites at the time of design. Titanium was still used on areas of heat buildup (such as the leading edges of the wings and air intakes) but the quantities were small. The MiG-31 however is composed of roughly half arc-welded nickel steel, the rest a mixture of alloys, titanium and composites (in order of amount).
Coming around to the front of the aircraft one can see the large air intakes - noticeably wider than those of the MiG-25 to accommodate the engine fans. The intakes are also shaped to contribute lift and have hinged leading edges, so the airflow into the engines may be controlled to a degree.
Looking up at the nose the first thing to stick out is the twin cockpits, much further forward than that of the MiG-25 which was almost nestled between the air intakes. A second crewmember is necessary to operate the radar and navigation systems, and some MiG-31s are equipped with a periscope so the navigator can fly the aircraft in an emergency (the forward view is obstructed by instrumentation). The remainder of the nose section sticks out about four metres beyond the front of the cockpit, enclosing the aircraft's radar and housing the refuelling probe if fitted.
The MiG-31 is powered by two Aviadvigatel D-30F6 twin-shaft afterburning turbofans, largely responsible for the range improvement over the MiG-25's turbojets. These deliver 34,170lbs of "wet" (afterburning) thrust, almost 2,000lbs more than the Pratt & Whitney J58s that power the SR-71 Blackbird. The maximum permitted speed for a MiG-31 is mach 2.83 but the absolute maximum is unknown. Although it is more powerful than the MiG-25 it is substantially heavier, so whether it is faster outright is hard to say.
The engines are fuelled by seven internal fuel tanks, with a combined capacity of just under 20,000 litres and a capacity for two 2,500l wing-mounted drop tanks. A partially retractable refuelling probe is fitted on the starboard side of the nose of some MiG-31s, providing an in-flight refuelling capability.
As for manoeuvrability the MiG-31 is little improved over the MiG-25, since despite its additional power and more developed airframe it is still extremely heavy. However like its predecessor, it is primarily an interceptor for larger and less manoeuvrable aircraft (except cruise missiles) so there is not a great need for it to be. It is well capable of outmanoeuvring most aircraft it may intercept.
The MiG-31 has a high degree of autonomy compared to its predecessor, which was all but a remote-controlled interceptor. Russia has an extensive ground control network for remote command of interceptors; interceptors would be directed by the ground towards their targets, the pilots taking over for the terminal stages of the interception. For whatever reason this was sidelined somewhat in the design of the MiG-31, which is able to navigate to and engage its targets autonomously (although it still has a GCI uplink capability a la the MiG-25).
The MiG-31 has a back seat for a second crew member to operate the radar and weapons systems, both of which are significantly advanced over those of the MiG-25. Most impressive of these is the SBI-16 Zaslon (NATO reporting name Flash Dance) phased-array radar, whose capabilities are second only to the AWG-9 radar of the F-14 Tomcat (though it is more powerful and furthermore, the most powerful radar ever fixed to an aircraft). It can track up to 10 targets at once up to 200km away while engaging a maximum of four of them.
The radar and navigation equipment underwent rigorous arctic trials during its development, as part of the MiG-31's mission was to patrol the far north of the Soviet Union to protect against attackers crossing the north pole. Given the high magnetic activity of this region it was important for the radar and associated systems to function correctly; many tests were performed on this aspect of the radar's operation, including a mission that overflew the north pole.
An unusual aspect of the Zaslon radar is that it is fixed in the nose of the aircraft, possibly the only example of this configuration. Most nose-mounted aircraft radar receivers are baby versions of commonly-seen radar dishes, which pivot inside the nose cone to steer the radar beam. This being the case, the radar receiver has to be narrower than the nose itself to be able to move. The MiG-31's radar, however, is fixed pointing straight forward and occupies the whole diameter of the nose; this is highly beneficial to radar performance, as radar range is directly related to the width of the receiver.
Since the radar receiver cannot move, its beam has to be steered electronically; it may also be 'shaped' to focus the beam on a certain area, and Mikoyan claims the beam may be focused backwards up to 120° either side of centre and still have the same detection and tracking abilities as in the aircraft's forward hemisphere.
The MiG-31 has such a powerful radar it is able to act as a mini-AWACS aircraft, sharing its target information with up to three MiG-21s, MiG-23s, MiG-25s, MiG-29s and Su-27s and direct them to targets. More impressively up to eight MiG-31s can link radars at maximum range, establishing a search area over 1000 miles across; extremely useful for areas with sparse ground radar coverage. When operating in this mode data is shared between all aircraft, so each aircraft's radar officer can view a readout of the entire search area.
In addition to the radar the foxhound also carries a retractable infrared receiver for passive target detection.
The MiG-31 is able to carry all missiles currently used by the Russian air force, including the staple diet of its predecessor, the AA-6 Acrid missiles. Commonly it is loaded with medium-range AA-8 Aphid "AMRAAMski" missiles and/or AA-9 Amos long-range missiles, the latter of which look thuthpithuthly like the US's AIM-54 Phoenix long-range air-to-air missile.
The initial production models of the MiG-31 were also equipped with a six-barrel rotary 23mm cannon, mounted in a fairing on the underneath of the starboard air intake. It has a fire rate of between 5,000 and 8,000 rounds a minute. Curiously designers only saw fit to provide a 260-round magazine, giving barely two seconds of firing time.
This variant replaced the MiG-31 in production in the early 1990s, a few years after an employee of the Phazotron radar design bureau in Moscow was executed for delivering information on radar and aircraft design to the CIA. Since many of the systems of the MiG-31 had been compromised they were upgraded or redesigned entirely; the MiG-31B featured an improved version of the Zaslon radar, an upgraded avionics system (5) and support for a new version of the AA-9 as well as other medium and short-range missiles.
The radar operator's position was made more enclosed with only small side windows and the periscope was removed. A MiG-31B looks much more like a MiG-25 with an extra cockpit grafted onto the existing one. Finally the partially-retractable refuelling probe fitted to some MiG-31s was replaced with a fully retractable refuelling probe.
A MiG-31 upgraded to MiG-31B standard, but minus the in-flight refuelling probe.
This was a variant built as an ejector seat testbed, much like the equivalent variant of the MiG-25. The seat to be tested would be fitted to the rear cockpit and the pilot would fly the aircraft from the front seat and conduct the test. Only one of these was built.
An ASAT (anti-satellite) platform. The aircraft could carry a single ASAT missile in lieu of its standard air-to-air payload, and is recognisable by the large winglets on the end of its wings, intended to improve stability at high altitudes. The radar on this variant was replaced with ballast and the cannon was removed.
Two of these variants were built and flight tested in 1987, but did not enter production.
A commercial variant of the MiG-31D that may be used for launching low-orbit satellites. It can launch a 100kg payload into a 200km orbit, though whether it has actually performed any launches or not is unknown.
A proposed multirole version of the foxhound intended to attract export orders, though again a variant which has yet to enter production. It can operate a variety of TV, laser and radar-guided air-to-ground missiles and has an improved Zaslon radar; this is able to track targets travelling in excess of mach 6 and guide the AA-12 Adder air-to-air missiles.
The cockpit layout of the MiG-31F was also revised, with colour CRT displays for both pilot and navigator, and a heads-up display (HUD) for the pilot.
A proposed export version of the MiG-31B. As is common to all export hardware, this aircraft is identical to the MiG-31B except the avionics suite, which has reduced capabilities. The MiG-31EF is the proposed export version of the MiG-31F. Only one or two prototypes of these variants have been built and no foxhounds of any type have yet been sold to other countries.
Roughly equivalent to the Foxbat-F, this is the Suppression of Enemy Air Defences (SEAD) variant of the Foxhound, based on the MiG-31F. It adds an air-to-surface capability to the fire control system, has an improved Zaslon radar which can track 24 targets at once against the 10 of the original.
This is a major proposed reissue of the foxhound, though another which will most likely not see service due to lack of export interest and Russia's current tight budget. It contains a further upgrade of the Zaslon radar and a new infrared receiver and a laser rangefinder in a pod on the underside of the fuselage. The flight controls are digital instead of analogue and improved multifunction displays are fitted in the cockpit. For some reason the back seat has even smaller side windows than previous versions, with no forward view at all; strangely the dual controls were put back so presumably the periscope was as well.
The fuselage is slightly expanded to make room for the extra hardware and for more fuel storage. The MiG-31M is probably the heaviest fighter aircraft ever, with a fully-loaded takeoff weight of 52 tonnes. The engines were uprated because of the increased weight, giving an extra 2,000lb of thrust each.
The cannon was removed from the MiG-31M and the extra space used for another two under-fuselage missiles, giving a total of six against the four of the original '31; there are also two extra hardpoints per wing, giving a capacity of up to twelve missiles with a combined weight of nine tonnes. Six of these can be launched simultaneously.
Six prototypes of this variant were built, including at least one with wingtip-mounted ECM pods. No more have been built and as yet none have been ordered.
Interesting MiG-31 story of dubious veracity
I'm mainly including this as I'm rather partial to stories of those perceived as the underdog briefly getting the upper hand. I mentioned the US's SR-71 Blackbird in my writeup of the MiG-25 Foxbat, the Foxhound's predecessor. That these two aircraft are the closest operational competitors to the Blackbird's dominance of the record books and performance figures. The Blackbird popped up a couple of times during my research for this writeup.
It's not difficult to find some mention in a Blackbird writeup that it was the aircraft the Soviet Union loved to hate, and it's certainly not hard to believe that was the case. No officially-acknowledged aircraft in the world (can you say Aurora?) can catch it and there it was, surveiling the Eastern Bloc with impunity despite several alleged attempts to shoot it down by various countries. It retired in 1994, little over a decade after the first Foxhound squadrons became operational. Some have speculated (though this is not what I'm doing) that this was in part an acknowledgement that the aircraft had become vulnerable.
According to several unverified reports (which sound like they have drawn from the same source, which is not specified by any of them), on June 3, 1986 six MiG-31s performed a coordinated intercept against a Blackbird on a training mission over the Barents Sea. This would have subjected the aircraft to an all-angle air-to-air attack which even its great speed and electronic countermeasures may not have been able to defeat. No missiles were fired (the interception took place over international waters) but the Soviets had certainly made their point.
It's worth mentioning here a brief conversation I had about this with another noder, who noted a group of MiG-31s "may be able to corner an SR-71, but they wouldn't be able to keep it". Posters on rec.aviation.military where this subject has come up were far less diplomatic:
"Not this bullshit old story AGAIN!! There is absolutely no basis for it (apart from the fervid imaginations of some of our Russian friends)".
"I also remember that same story. The reason I don't believe it is because they did not shoot the SR-71 down. If they shot down a 747 and got away with it what's the big deal if a military recon plane is shot down. They could say it was in there (sic) airspace and there would have been nothing we could do about it"
"I spoke with the CO of the 9 RW when this was
supposed to have happened, and it never happened. The Russians were noever (sic) even close to shooting or locking onto a SR-71"
It's also worth mentioning that these posters aren't necessarily any more credible than the story they are rubbishing, but this was as close as I could get to some balance.
mdn says re MiG-31 Foxhound: I think I know where the myth of the MiG-31:s locking onto an SR-71 comes from. Here in Sweden, the same story has been circling around aswell. In the Swedish version however, the feat was made by an JA 37 Viggen over the Baltic Sea. This was discussed on a Swedish military forum where one member actually confirmed it, quoting an air force officer he spoke to during his military service as his source. He posted a quite detailed story about it.
The MiG-31, or a version
of it, is also the subject of two books by Craig Thomas
and its sequel Firefox Down
. Exaggerated reports of the capabilities of the MiG-31 in Western press led to further exaggeration for the novel's fictional counterpart, creating a superlative fighter that could exceed mach 5, outmanoeuvre the best (well, second-best) Soviet aircraft and shoot them down with a thought-guided weapons system.
The book and its sequel follow an attempt by the West to steal said aircraft. They are short on technical details so the aircraft itself and the tension that remain have both aged very well. Buy the first book but forget the second, unless tearing out all but the first and final 20 pages appeals to you.
As always, sources on Russian military hardware often conflict and in particular, information on variant designations and years of introduction are difficult to pin down. Please /msg me any corrections.
- http://www.b-domke.de/AviationImages/Foxhound.html (photographs)
- Stock, Alex; "MiG-31, Mikoyan 'Foxhound'";
- Pike, John; "MiG-31 FOXHOUND";
- (Author not specified); "Lockheed SR-71";
- (Author not specified); "Mikoyan MiG-31";
- (Author not specified, possibly copied); "Mig-31";
- (Author not specified); "SR-71 -- the Ultimate Target";
- Thai Technics.Com; "MIG-31 Foxhound";
- he Hindu; "IAF invited to gauge MiG-31 performance";
- "MiG-31 "Foxhound" - Strategic interceptor fighter";
- Kedzierski, Lukasz; "Mig-31 Foxhound";
- Afterburner (Author not specified); "Mikoyan Gurevich MiG-31 Foxhound";
- Hillebrand, Niels; "Mikoyan-Gurevich MiG-31 Foxhound;
- Information"; <http://www.milavia.net/aircraft/mig-31/mig-31.htm>
- History"; <http://www.milavia.net/aircraft/mig-31/mig-31_his.htm>
- Specification"; <http://www.milavia.net/aircraft/mig-31/mig-31_specs.htm>
- Goebel, Greg; "MiG-31 Foxhound";
<http://www.vectorsite.net/avmig25.html> (public domain)
- Viktor Belenko