The Su-27 was developed by the Soviet Union at the tail end of the Cold War and was intended to play more or less the same role as the American F-14 or F-15 fighters—a fast and maneuverable air escort or air superiority fighter. Moscow’s Flankers would have protected the Soviet Union’s long-range bombers like the Tu-22, Tu-95, and Tu-160. Today, it still serves in this role with the Russian Air Force.
It is obvious why China would want to domestically produce the Su-27 Flanker—it’s agile, has a high top speed, and good range. In fact, the Su-27 is supermaneuverable. For a time, it was the airframe of choice for the Russian Knights, an aerobatic demonstration team similar to the U.S. Navy’s Blue Angels.
It is also well-armed with ten external hardpoints for an extensive weapons loadout, and an internally housed 30 millimeter cannon. One of the critical drawbacks of the Su-27 is that it is not capable of aerial refueling and so can’t feed its thirsty twin-engine design.
In the aftermath of the Soviet Union’s dissolution, a cash-strapped Russia turned to the outside world for potential weapons export customers and found a receptive client—China.