The Mikoyan-Gurevich MiG-25 (Russian: Микоян и Гуревич МиГ-25; NATO reporting name: Foxbat) is a supersonic interceptor and reconnaissance aircraft that is among the fastest military aircraft to enter service. Designed by the Soviet Union's Mikoyan-Gurevich bureau, it is an aircraft built primarily using stainless steel. It was to be the last plane designed by Mikhail Gurevich, before his retirement. The first prototype flew in 1964 and the aircraft entered service in 1970. Although its thrust was sufficient to reach Mach 3.2+, its speed was limited to prevent engines from overheating at higher air speeds and possibly seriously damaging them, and therefore the operational top speed was limited to Mach 2.83. The MiG-25 features a powerful radar and four air-to-air missiles, and it still has the world record for reached altitude of 38 km (125,000 ft). The appearance of the MiG-25 sparked concern in the West and prompted increases in performance requirements for the McDonnell Douglas F-15 Eagle, then already under development in the late 1960s. The capabilities of the MiG-25 were better understood by the West in 1976 when Soviet pilot Viktor Belenko defected in a MiG-25 to the United States via Japan. Production of the MiG-25 series ended in 1984 after completion of 1,186 aircraft. A symbol of the Cold War, the MiG-25 flew with Soviet allies and former Soviet republics, remaining in limited service in several export customers. It is one of the highest-flying military aircraft,[6] one of the fastest serially produced interceptor aircraft, and the second-fastest serially produced aircraft after the SR-71 reconnaissance aircraft, which was built in very small numbers compared to the MiG-25.[8] As of 2018, the MiG-25 remains the fastest manned serially produced aircraft in operational use and the fastest plane that was offered for supersonic flights and edge-of-space flights to civilian customers. Because of the thermal stresses incurred in flight above Mach 2, the Mikoyan-Gurevich OKB had difficulties choosing what materials to use for the aircraft. They had to use E-2 heat-resistant Plexiglas for the canopy and high-strength stainless steel for the wings and fuselage. Using titanium rather than steel would have been ideal, but it was expensive and difficult to work with. The problem of cracks in welded titanium structures with thin walls could not be solved, so the heavier nickel steel was used instead. It cost far less than titanium and allowed for welding, along with heat-resistant seals. The MiG-25 was constructed from 80% nickel-steel alloy, 11% aluminium, and 9% titanium. The steel components were formed by a combination of spot welding, automatic machine welding, and hand arc welding methods. The MiG-25 was theoretically capable of a maximum speed exceeding Mach 3 and a ceiling of 27 km (89,000 ft). Its high speed was problematic: Although sufficient thrust was available to reach Mach 3.2, a limit of Mach 2.83 had to be imposed as the engines tended to overspeed and overheat at higher airspeeds, possibly damaging them beyond repair. For extensive details on background, development, operational history and 25 variants, click here.
