The Mikoyan-Gurevich MiG-21 (Russian: Микоян и Гуревич МиГ-21; NATO reporting name: Fishbed) is a supersonic jet fighter and interceptor aircraft, designed by the Mikoyan-Gurevich Design Bureau in the Soviet Union. Its nicknames include: "balalaika", because its planform resembles the stringed musical instrument of the same name; "Ołówek", Polish for "pencil", due to the shape of its fuselage, and "Én Bạc", meaning "silver swallow", in Vietnamese. Approximately 60 countries across four continents have flown the MiG-21, and it still serves many nations six decades after its maiden flight. It made aviation records, becoming the most-produced supersonic jet aircraft in aviation history, the most-produced combat aircraft since the Korean War and, previously, the longest production run of any combat aircraft (now exceeded by both the McDonnell Douglas F-15 Eagle and General Dynamics F-16 Fighting Falcon). 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 the delta wings found on production variants was the Ye-4. It made its maiden flight on 16 June 1955 and 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'. 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. Its basic layout was used for numerous other Soviet designs; delta-winged aircraft included the Su-9 interceptor and fast E-150 prototype from the MiG bureau, while the successful mass-produced frontline 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 ultimately proved to have limited development potential, mainly due to the small available space for the radar. 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 an inlet cone in the air intake. On early model MiG-21s, the 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. Later versions shifted the pitot tube attachment point 15 degrees to the right, as seen from the cockpit, and had an emergency pitot head on the right side, just ahead of the canopy and below the pilot's eyeline. For more details on the development, design and operational history of the MiG-21, click here.