While the Su-57 project has great potential, it is not the only next-generation fighter program intended to replace the Su-27 Flanker family.
A single prototype of the Su-47 was built and made its maiden flight in September 1997. This platform serves as an invaluable experiment, given a number of complex technologies including advanced composite materials and flight technology, which is the basis for the later Su-35 and Su-57 fighters.
Project Su-47 was developed in the 1980s, under the management of the Sukhoi design bureau. The Su-47 project was conducted concurrently with the MiG 1.44 fifth generation fighter, and the Flanker family upgrade programs that would later become the Su-30, Su-34 and Su-35.
What sets the Su-47 apart from the rest was its forward-swept wing. These wings gave the fighter extremely versatile in maneuverability. It was equipped with a pair of Soloviev D-30F6 afterburning turbofan engines that made it a leading fighter in the world.
Special wing design gave the Su-47 a higher lift-to-drag ratio, superior stability at high attack angle, a lower minimum flight speed, improved stall resistance and anti-spin characteristics. The wing design also gave the fighter a significantly greater range at subsonic speed and a shorter take-off and landing distance.
Although formidable for close combat, the downside of the forward-swept wing design was that the fighter’s speed was limited, reaching only Mach 1.6, equivalent to the speed of the US F-35A.
In addition, this design produces wing twisting as it bends under load, resulting in greater stress on the wing than for a similar straight or aft-swept wing. As a result, almost 90% of the material used for the fighter’s wings should be composite and much more susceptible to wear and tear than the wings of conventional aircraft.
The Su-47 prototype used the same DF-30 engines as on the MiG-31. The fuselage and landing gears were inherited from the Su-27 to reduce development costs. The fighter was similar in size to the Su-27, making the Su-47 the leading Russian air superiority fighter at the time.