The Sukhoi Su-35 (Russian: Сухой Су-35; NATO reporting name: Flanker-E) is a designation for two separate, heavily upgraded derivatives of the Su-27 'Flanker'. They are single-seat, twin-engine, supermaneuverable multirole fighters, designed by Sukhoi and built by Komsomolsk-on-Amur Aircraft Production Association (KnAAPO). The Su-35 is also known as Super Flanker.
The first variant was designed during the 1980s, when Sukhoi was seeking to upgrade its high-performance Su-27, and was initially known as the Su-27M. Later re-designated Su-35, this derivative incorporated aerodynamic refinements to increase manoeuvrability, enhanced avionics, longer range, and more powerful engines. The first Su-35 prototype, converted from a Su-27, made its maiden flight in June 1988. More than a dozen of these were built, some of which were used by the Russian Knights aerobatic demonstration team. The first Su-35 design was later modified into the Su-37, which possessed thrust vectoring engines and was used as a technology demonstrator. A sole Su-35UB two-seat trainer was built in the late 1990s that strongly resembled the Su-30MK family.
In 2003, Sukhoi embarked on a second modernization of the Su-27 to produce what the company calls a 4++ generation fighter that would bridge the gap between legacy fighters and the upcoming fifth generation Sukhoi PAK FA. This derivative, while omitting the canards and air brake, incorporates a reinforced airframe, improved avionics and radar, thrust-vectoring engines, and a reduced frontal radar signature. In 2008 the revamped variant, erroneously named the Su-35BM in the media, began its flight test programme that would involve four prototypes, one of which was lost in 2009.
The Russian Air Force has ordered 48 production units, designated Su-35S, of the newly revamped Su-35. Both Su-35 models are marketed to many countries, including Brazil, China, India, Indonesia, and South Korea, but so far have not attracted any export orders. Sukhoi originally projected that it would export more than 160 units of the second modernized Su-35 worldwide.