SU-47, with a Railgun

The Sukhoi Su-47 Berkut (Russian: ????? ??-47 «??????», lit.?'Golden Eagle') (NATO reporting name Firkin]), also designated S-32 and S-37 during initial development, was a Russian experimental supersonic jet fighter developed by the JSC Sukhoi Company. A distinguishing feature of the aircraft was its forward-swept wing 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 fourth-generation fighter Su-35 and fifth-generation fighter Su-57