Primarily a technology demonstrator for future Russian fighters such as the Sukhoi Su-57, it became the principal test bed for composite materials, sophisticated control systems and new airframe technologies.
 
Ordered in 1983 but funding was frozen upon the dissolution of the USSR. Further funding was provided by Sukhoi.
 
Extremely agile at subsonic speeds and highly maneuverable in supersonic flight, the Berkut would have made a formidable opponent in the skies above Europe.