The Su-47 Berkut, also known as the S-37, is an experimental supersonic jet fighter developed by Russia's Sukhoi Design Bureau. It features forward-swept wings, which are unusual in modern fighter aircraft design. The forward-swept wings provide enhanced maneuverability and stability at high angles of attack. The Su-47 was intended to explore advanced aerodynamic concepts and technologies for future fighter aircraft, With only a few prototypes were built.