Science Fair Project Encyclopedia
The MiG-25 Foxbat, despite Western panic about its tremendous speed, was an extremely limited aircraft, making substantial sacrifices in capability for the sake of high speed, altitude, and rate of climb. It was almost unmaneuverable at interception speeds, it was difficult to fly at low level, and its thirsty turbojet engines resulted in a very short combat range at supersonic speeds. Its radar was powerful, to burn through ECM, but primitive, with no look-down capability against low-flying targets. The 'Foxbat' proved to be more useful in the reconnaissance role than as an interceptor, and by the mid-1970s was clearly inadequate against the latest NATO aircraft, particularly the B-1 Lancer, and cruise missiles.
Development of the 'Foxbat's' replacement began with the Ye-155MP development machine, which first flew on 16 September 1975. Although it bore a superficial resemblance to a stretched MiG-25, with a longer fuselage for a rear cockpit and radar operator, it was in many respects a totally new design. Soviet manufacturing limitations had forced the 'Foxbat' 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 somewhat stronger, enabling supersonic load ratings to rise to 5g (compared to the 'Foxbat's' 4.5g). More importantly, supersonic speed was now possible at low level. Fuel capacity was increased, and new, more efficient low-bypass turbofan engines were introduced.
The most important development, however, was the introduction of a much more advanced radar capable of both look-up and look-down engagement, 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-control interception (GCI) to greater autonomy for flight crews.
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.
The MiG-31 proved to be extremely capable when originally introduced, and 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 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 weapons system officer.
The wings and airframe of the MiG-31 are considerably stronger than the MiG-25, allowing supersonic speed at low level. Powerful Soloviev D-30F6 engines (turbofans with such a low bypass ratio that they are officially described as "bypass turbojets") 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).
Although more efficient than the MiG-25's turbojets, the MiG-31's engines still have extremely high fuel consumption. As a result the aircraft's fuel fraction has been increased to 0.40: a staggering 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 in-flight refueling probes, which have presumably been retrofitted to many early aircraft as well.
Despite the stronger airframe, the 'Foxhound' has extremely limited maneuverability, limited to a maximum of 5g at supersonic speeds. It is not intended for close-combat or rapid turning.
The MiG-31 was the world's first operational fighter with a phased array radar, the extremely powerful 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 system (IRST) in a retractable undernose fairing. Up to four MiG-31s can coordinate via datalink, spaced up to 200 km (125 mi) apart to cover a wide swath of territory. The radar is controlled by the backseater, whose cockpit has only two small vision ports in the sides of the canopy, limiting visibility.
The MiG-31M/MiG-31D/MiG-31BS-standard aircraft have an upgraded Zaslon-M 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). ECM capability is also upgraded, with new ECM pods on the wingtips.
The 'Foxhound's' main armament is the Vympel R-33 (AA-9 'Amos') air-to-air missile, of which four are carried under the belly. The R-33 is the Russian equivalent of the US 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. For the terminal homing phase, it switches on its own active radar. A more advanced version of the weapon, the R-37, has been developed, using folding stabilizers to reduce its carriage 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 'Foxhounds' can carry the newer R-77 (AA-12 'Adder'), the so-called "AMRAAMski") on the wing pylons.
Unlike the 'Foxbat,' the MiG-31 has an internal cannon, the six-barrel GSh-6-23, with 260 rounds of ammunition, mounted above the starboard main landing gear bay. The GSh-6-23 has an extremely high rate of fire, claimed to be more than 8,000 rpm, which gives less than four seconds' firing time. The MiG-31M deletes the cannon in favor of an additional two fuselage recesses for R-33/R-37 missiles — given the 'Foxhound's' almost non-existent close-combat maneuverability, probably more useful.
A new version of the 'Foxhound' with upgraded avionics, the MiG-31B, was introduced in 1990. Its development was a result of the Soviet discovery that Phazotron radar division engineer Alexander 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 MiG-31M standard. Upgraded aircraft are reportedly designated MiG-31BM, adding some additional features like GPS navigation 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.
Author Craig Thomas used the designation MiG-31 in his fiction books Firefox (and the subsequent movie starring Clint Eastwood) and Firefox Down . Although the books reflected Western fears of the advanced new aircraft, Thomas's Firefox bore little resemblance to the real 'Foxhound'.
- 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)
- Maximum takeoff weight: 46,200 kg (101,900 lb)
- Powerplant: 2x Soloviev D-30F6 afterburning turbofans, each 9,500 kgf (93 kN, 20,900 lbf) military thrust or 17,500 kgf (172 kN, 38,600 lbf) with afterburner
- Maximum speed: 1,500 km/h (930 mph) clean at sea level; 3,000 km/h (1,860 mph) at altitude
- Combat radius: 720 km (450 mi)
- Ferry range: 3,300 km (2,050 mi)
- Service ceiling: 20,600 m (67,600 ft)
- Rate of climb: 12,500 m/min (41,000 ft/min)
- Wing loading: 666 kg/m² (136 lb/ft²)
- Thrust/mass ratio: 0.85:1
- 1x GSh-6-23 23mm cannon with 260 rounds
- four fuselage recesses for R-33/R-37 (AA-9 'Amos') long-range air-to-air missiles
- four underwing pylons for choice of:
- Some aircraft equipped to launch Kh-31P and Kh-58 anti-radiation missiles in the "Wild Weasel" SEAD role.
|Related Lists||List of military aircraft of the Soviet Union and the CIS - List of fighter aircraft|
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