The Sukhoi Su-47 experimental fifth-generation fighter, previously the S-37 Berkut (Golden Eagle), completed the first stage of flight trials last month, having logged 149 flights. Four pilots, including one from the Russian air force, have flown the aircraft. The Su-47 was built before 1996 to demonstrate technologies including forward-swept wings, thrust vectoring, high manoeuvrability and low radar cross section.

Source: Flight International