Mikoyan-Gurevich MiG-21

The Mikoyan-Gurevich MiG-21 (Russian: Микоян и Гуревич МиГ-21; NATO reporting name: Fishbed) is a supersonic jet fighter aircraft, designed by the Mikoyan-Gurevich Design Bureau in the Soviet Union. It was popularly nicknamed "Balalaika", from the aircraft's planform-view resemblance to the Russian stringed musical instrument or ołówek (English: pencil) by Polish pilots due to the shape of its fuselage.^[2]
Early versions are considered second-generation jet fighters, while later versions are considered to be third-generation jet fighters. Some 50 countries over four continents have flown the MiG-21, and it still serves many nations a half-century after its maiden flight. The fighter made aviation records. At least by name, it is the most-produced supersonic jet aircraft in aviation history and the most-produced combat aircraft since the Korean War, and it had the longest production run of a combat aircraft (1959 to 1985 over all variants).^[1]

Origins

The MiG-21 jet fighter was a continuation of Soviet jet fighters, starting with the subsonic MiG-15 and MiG-17, and the supersonic MiG-19. A number of experimental Mach 2 Soviet designs were based on nose intakes with either swept-back wings, such as the Sukhoi Su-7, or tailed deltas, of which the MiG-21 would be the most successful.
Development of what would become the MiG-21 began in the early 1950s, when Mikoyan OKB finished a preliminary design study for a prototype designated Ye-1 in 1954. This project was very quickly reworked when it was determined that the planned engine was underpowered; the redesign led to the second prototype, the Ye-2. Both these and other early prototypes featured swept wings—the first prototype with delta wings as found on production variants was the Ye-4. The Ye-4 made its maiden flight on 16 June 1955 and made its first public appearance during the Soviet Aviation Day display at Moscow's Tushino airfield in July 1956.
In the West, due to the lack of available information, early details of the MiG-21 often were confused with those of similar Soviet fighters of the era. In one instance, Jane's All the World's Aircraft 1960–1961 listed the "Fishbed" as a Sukhoi design and used an illustration of the Su-9 'Fishpot'.

Design

MiG-21 at the Aviation Museum of Central Finland in Jyväskylä.

The MiG-21 was the first successful Soviet aircraft combining fighter and interceptor characteristics in a single aircraft. It was a lightweight fighter, achieving Mach 2 with a relatively low-powered afterburning turbojet, and is thus comparable to the American Lockheed F-104 Starfighter and Northrop F-5 Freedom Fighter and the French Dassault Mirage III.^[1] Its basic layout was used for numerous other Soviet designs; delta-winged aircraft included Su-9 interceptor and the fast E-150 prototype from MiG bureau while the mass-produced successful front fighter Su-7 and Mikoyan's I-75 experimental interceptor combined a similar fuselage shape with swept-back wings. However, the characteristic layout with the shock cone and front air intake did not see widespread use outside the USSR and finally proved to have limited development potential, mainly because of the very small space available for the radar.
Like many aircraft designed as interceptors, the MiG-21 had a short range. This was not helped by a design defect where the center of gravity shifted rearwards once two-thirds of the fuel had been used.^{[citation needed]} This had the effect of making the plane uncontrollable, resulting in an endurance of only 45 minutes in clean condition. The issue of the short endurance and low fuel capacity of the MiG-21F, PF, PFM, S/SM and M/MF variants—though each had a somewhat greater fuel capacity than its predecessor—led to the development of the MT and SMT variants. These had a range increase of 250 km (155 mi) compared to the MiG-21SM, but at the cost of worsening all other performance figures (such as a lower service ceiling and slower time to altitude).^[1]
The delta wing, while excellent for a fast-climbing interceptor, meant any form of turning combat led to a rapid loss of speed. However, the light loading of the aircraft could mean that a climb rate of 235 m/s (46,250 ft/min) was possible with a combat-loaded MiG-21bis,^[1] not far short of the performance of the later F-16A. Given a skilled pilot and capable missiles, it could give a good account of itself against contemporary fighters. Its G-limits were increased from +7Gs in initial variants to +8.5Gs in the latest variants.^[3] It was replaced by the newer variable-geometry MiG-23 and MiG-27 for ground support duties. However, not until the MiG-29 would the Soviet Union ultimately replace the MiG-21 as a maneuvering dogfighter to counter new American air superiority types.
The MiG-21 was exported widely and continues to be used. The aircraft's simple controls, engine, weapons, and avionics were typical of Soviet-era military designs. The use of a tail with the delta wing aids stability and control at the extremes of the flight envelope, enhancing safety for lower-skilled pilots; this in turn enhanced its marketability in exports to developing countries with limited training programs and restricted pilot pools. While technologically inferior to the more advanced fighters it often faced, low production and maintenance costs made it a favorite of nations buying Eastern Bloc military hardware. Several Russian, Israeli and Romanian firms have begun to offer upgrade packages to MiG-21 operators, designed to bring the aircraft up to a modern standard, with greatly upgraded avionics and armaments.^[1]

Production

MiG-21 at Aleksotas Airport (S. Dariaus / S. Gireno), Kaunas (EYKS)

A total of 10,645 aircraft were built in the USSR. They were produced in three factories: GAZ 30^{[N 1]} (3,203 aircraft) in Moscow (also known as Znamya Truda), GAZ 21 (5,765 aircraft) in Gorky ^{[N 2]} and at GAZ 31 (1,678 aircraft) in Tbilisi. Generally, Gorky built single-seaters for the Soviet forces. Moscow constructed single-seaters for export, and Tbilisi manufactured the twin-seaters both for export and for the USSR, though there were exceptions. The MiG-21R and MiG-21bis for export and for the USSR were built in Gorky, 17 single-seaters were helmed in Tbilisi (MiG-21 and MiG-21F), the MiG-21MF was first constructed in Moscow and then Gorky, and the MiG-21U was built in Moscow as well as in Tbilisi.

Design

The MiG-21 has a delta wing. The sweep angle on the leading edge is 57° with a TsAGI S-12 airfoil. The angle of incidence is 0° while the dihedral angle is −2°. On the trailing edge there are ailerons with an area of 1.18 m², and flaps with an area of 1.87 m². In front of the ailerons there are small wing fences.
The fuselage is semi-monocoque with an elliptical profile and a maximum width of 1.24 m (4 ft 1 in). The air flow to the engine is regulated by a cone in the air intake. On early model MiG-21s, the intake cone has three positions. For speeds up to Mach 1.5 the cone is fully retracted to the maximum aft position. For speeds between Mach 1.5 and Mach 1.9 the cone moves to the middle position. For speeds higher than Mach 1.9 the cone moves to the maximum forward position. On the later model MiG-21PF, the intake cone moves to a position based on the actual speed. The cone position for a given speed is calculated by the UVD-2M system using air pressures from in front and behind the compressor of the engine. On both sides of the nose there are gills to supply the engine with more air while on the ground and during takeoff. In the first variant of the MiG-21, the pitot tube is attached to the bottom of the nose. After the MiG-21P variant, this tube is attached to the top of the air intake.

MiG-21F-13 cockpit at the Aviation Museum in Bucharest, Romania

The cabin is pressurized and air conditioned. On variants prior to the MiG-21PFM, the cabin canopy is hinged at the front. When ejecting, the SK-1 ejection seat connects with the canopy to make a capsule that encloses the pilot. The capsule protects the pilot from the high speed airflow encountered during high speed ejections. After ejection, the capsule opens to allow the pilot to parachute to the ground. However, ejecting at low altitudes can cause the canopy to take too long to separate. Some pilots have been killed after ejecting at low altitudes. Starting from the MiG-21PFM, the canopy is hinged on the right side of the cockpit.

MiG-21F-13 view from behind

On the under side of the aircraft there are three air brakes, two at the front and one at the back. The front air brakes have an area of 0.76 m², and a deflection angle of 35°. The back air brake has an area of 0.46 m² and a deflection angle of 40°. The back air brake is blocked if the airplane carries an external fuel tank. Behind the air brakes are the bays for the main landing gear. Also on the under side of the airplane, just behind the trailing edge of the wing are attachment points for two JATO rockets. The front section of the fuselage ends at former #28. The back section of the fuselage starts at former #28a and is removable for engine maintenance.
The empennage of the MiG-21 consists of a vertical stabilizer, a stabilator and a small fin on the bottom of the tail to improve yaw control. The vertical stabilizer has a sweep angle of 60° and an area of 5.32 m² (on earlier version 3.8 m²) and a rudder. The stabilator has a sweep angle of 57°, an area of 3.94 m² and a span of 2.6 m.
The MiG-21 uses a tricycle type undercarriage. On most variants the main landing gear uses tires that are 800 mm in diameter and 200 mm in width. Only the MiG-21F variants use tires with the size 660x200 mm. The wheels of the main landing gear retract into the fuselage after rotating 87° and the shock absorbers retract into the wing. The nose gear retracts forward into the fuselage under the radar.

Specifications (Mikoyan-Gurevich MiG-21-93)

Data from ^[1]

General characteristics

Crew: 1
Length: 14.5 (with pitot) m (47 ft 6.86 in)
Wingspan: 7.154 m (23 ft 5.66 in)
Height: 4.125 m (13 ft 6.41 in)
Wing area: 23.0 m² (247.3 ft²)
Gross weight: 8,825 kg (19,425 lb)
Powerplant: 1 × Tumansky R25-300, 40.21 kN (9,040 lbf) thrust dry, 69.62 kN (15,650 lbf) with afterburner each