Sukhoi Su-47 Berkut (Russian: Сухой Су-47 «Беркут», lit. 'Eagle' in Kazakh language) (NATO reporting name Firkin[1]), also designated S-32 and S-37 during initial development, was a Russian experimental supersonic technology demonstrator developed by the JSC Sukhoi Company. A distinguishing feature of the aircraft was its forward-swept wing[2] which gave the aircraft excellent agility and maneuverability. While serial production of the type never materialized and the configuration was not further pursued, the sole aircraft produced served as a technology demonstrator prototype for a number of advanced technologies later used in the fourth-generation fighter Su-35 and the fifth-generation fighter Su-57.