In the late 1950s, the Sukhoi Design Bureau, already an established fighter maker, started work on a successor to its Su-9 and Su-11 single-engined interceptors for the national Air defense Force. Similar to its predecessors, the new aircraft designated Su-15 had delta wings; unlike the Su-9/Su-11, however, it had twin engines and lateral air intakes freeing up the nose for a powerful fire control radar. First flown in May 1962, the Su-15 officially entered service in 1965 and was built in several versions, the late ones having cranked-delta wings and a more capable radar. Being an air...

The MiG-31 started life as an advanced derivative of the famous MiG-25P interceptor, becoming the first Soviet fourth-generation combat aircraft. First flown in 1975, it differed from its progenitor primarily in having a crew of two (pilot and weapons systems operator), a highly capable passive phased-array radar a world first and new R-33 long-range missiles as its primary armament. The maximum speed was an impressive Mach 2.82, the cruising speed being Mach 2.35. The type entered service in 1981; more than 500 copies were built between 1981 and 1994. The powerful radar and other avionics...