Mikoyan MiG-31
) (
NATO reporting name Foxhound) is a supersonic
interceptor developed to replace the
MiG-25. It was the most advanced interceptor fielded by the
Soviet Union before its
dissolution.
The
MiG-25 Foxbat, despite Western panic about its tremendous speed, made substantial sacrifices in capability for the sake of high speed, altitude, and rate of climb. It lacked maneuverability at interception speeds, it was difficult to fly at low altitudes, and its thirsty
turbojet engines resulted in a very short combat range at supersonic speeds. The turbojet engines would also have to be exchanged after a flight in which its maximum speed of Mach 3 had been achieved. Its
radar was also powerful enough to burn through
ECM, but primitive, operating on
vacuum tubes. The Foxbat proved to be more useful in the
reconnaissance role than as an interceptor, and by the mid-
1970s was clearly inadequate.
Development of the 'Foxbat's' replacement began with the
Ye-155MP () prototype which first flew on
16 September 1975. Although it bore a superficial resemblance to a stretched MiG-25 with a longer fuselage for the radar operator cockpit, it was in many respects a totally new design. Soviet manufacturing limitations forced the MiG-25 to use nickel steel for 80% of its structure. The Ye-155MP doubled the use of
titanium to 16% and tripled the
aluminum content to 33% to reduce structural mass. The new structure was also stronger, enabling supersonic load ratings to rise to 5, compared to the 'Foxbat's' 4.5. More importantly, supersonic speed was now possible at low level. Fuel capacity was increased, and new, more efficient low-bypass
turbofan engines were fitted.
The most important development was the introduction of an advanced radar capable of both look-up and look-down engagement (locating targets above and below the aircraft), as well as multiple target tracking. This finally gave the Soviets an interceptor capable of engaging the most likely Western intruders at long range. It also reflected a policy shift from reliance on
ground-controlled interception (GCI) to greater autonomy for flight crews.
Like its MiG-25 predecessor, the MiG-31 was surrounded by early speculation and misinformation concerning its design and capabilities. 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 capability to intercept cruise missiles. According to his testimony, the new interceptor was to have air intakes similar to the
MiG-23, which the MiG-31 in reality does not have, at least not in production variants. While undergoing testing, a MiG-31 was spotted by a
reconnaissance satellite at the Zhukovsky flight test centre near the town of
Ramenskoye. The images were interpreted as a fixed-wing interceptor version of a
swing-wing fighter
codenamed the
Ram-K. The latter was eventually revealed to be the
Sukhoi Su-27, a wholly unrelated design.
Series production began in
1979, with operational models entering
PVO service in
1982. It was first photographed by a
Norwegian pilot over the
Barents Sea in
1985.
The MiG-31 was sought after for a variety of long-range missions. Following the collapse of the USSR, however, the budget for spares and maintenance collapsed, leaving many squadrons unable to maintain their complex aircraft. By
1996 only 20% of remaining aircraft were reportedly serviceable at any time.
About 500 MiG-31s were produced, approximately 280-300 of which remain in Russian service, with another 30 or so in
Kazakhstan. Some reports suggest the Foxhound is likely to be withdrawn soon, if it has not been already, although the
Russian Air Force would like to keep the type in service through 2010.
Like the MiG-25, the Foxhound 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 Foxbat, it has two seats, with the rear occupied by a dedicated
weapon systems officer.
Airframe and engines
|
MiG-31 Foxhound in flight. |
The wings and airframe of the MiG-31 are stronger than the MiG-25, permitting supersonic flight at low altitudes.
Soloviev D-30F6 turbofans (also described as "bypass
turbojets" due to the low
bypass ratio) allow a maximum speed of
Mach 1.23 at low altitude. High-altitude speed is temperature-redlined to Mach 2.83 â€" 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.
Although more efficient than the MiG-25's turbojets, the MiG-31's engines still have high fuel consumption. As the result, the aircraft's fuel fraction has been increased to 0.40 â€" 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 liters (1,320 U.S.
gallons) of external fuel. Late-production aircraft have
aerial refueling probes.
Despite the stronger airframe, the Foxhound is limited to a maximum of 5 G at supersonic speeds. It is not designed for close-combat or rapid turning.
Electronics suite
|
MiG-31 Foxhound showing its Zaslon phased array radar. |
The MiG-31 was the world's first operational fighter with a
phased array radar, 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
R-33 (AA-9 'Amos') missiles. It is claimed to have a limited astern coverage (perhaps the reason for the
radome-like protuberance above and between the engines). The radar is matched with an
infrared search and tracking (IRST) system in a retractable undernose fairing. Up to four MiG-31s, spaced up to 200 km (125 mi) apart to cover a wide swath of territory, can coordinate via
datalink. The radar is controlled by the back-seater, whose cockpit has only two small vision ports in the sides of the canopy.
The MiG-31M/MiG-31D/MiG-31BS-standard aircraft have an upgraded
Zaslon-M radar with greater detection range (said to be 400 km (250 mi) against
AWACS-size targets) and the ability to attack six targets simultaneously. The back-seater's controls are replaced with modern multi-function displays (MFDs).
Electronic countermeasures capability is also upgraded, with new ECM pods on the wingtips.
Armament
|
MiG-31 Foxhound armed with AA-9 missiles. |
The MiG-31's main armament is four
Vympel R-33 (AA-9 'Amos')
air-to-air missiles carried under the belly. The R-33 is the Russian equivalent of the
United States Navy 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. It switches on its own active radar for the terminal homing phase. A more advanced version of the weapon, the
R-37, has been developed, using folding stabilizers to reduce its stored size.
Other weapons include the old
R-40 (AA-6 'Acrid'), originally deployed on the MiG-25, and the
R-60 (AA-8 'Aphid') or
R-73 (AA-11 'Archer') short-range missiles, carried on wing pylons. Some refitted MiG-31s can carry the newer
R-77 (AA-12 'Adder') on the wing pylons.
Unlike the MiG-25, the MiG-31 has an internal
cannon, a six-barrel
GSh-6-23 with 260 rounds of ammunition, mounted above the starboard main
landing gear bay. The GSh-6-23 has a claimed rate of fire of over 8,000 rounds per minute. The MiG-31M deletes the cannon in favor of an additional two fuselage recesses for R-33/R-37 missiles.
|
Russian Air Force MiG-31BM on display. |
A new version of the 'Foxhound' with upgraded
avionics, the
MiG-31B, was introduced in
1990. Its development was the result of the Soviet discovery that
Phazotron radar division engineer
Adolf Tolkachev had sold information on advanced radar to the West. Tolkachev was executed, and a new version of the compromised radar was hastily developed. Many earlier MiG-31s were upgraded to the new standard, designated
MiG-31BS.
Development of a more comprehensive advanced version, the
MiG-31M, began in
1983 and first flew in
1986, but the
collapse of the Soviet Union prevented it from entering full production. Since
1991 some existing aircraft have been upgraded to the MiG-31M standard. Upgraded aircraft are reportedly designated
MiG-31BM, adding some additional features like
Global Positioning System receivers.
Several other variants have been developed, including a dedicated
anti-satellite missile carrier, the
MiG-31D, a similar satellite-launching aircraft,
MiG-31A, a proposed multi-role version,
MiG-31F, and a downgraded export version,
MiG-31E, but most have not been built in any quantity, if at all.
*
Kazakhstan,
Russia /
Soviet Union.
{{aircontent|related=
MiG-25|similar aircraft=
F-14 Tomcat -
F-15 Eagle|sequence=
MiG-23 -
MiG-25 -
MiG-27 -
MiG-29 -
MiG-31 -
MiG-33 -
MiG-35|lists=
List of military aircraft of the Soviet Union and the CIS -
List of fighter aircraft
