I think China again has copied design from Sukhoi Su-47
Su-47manoeuvrability
The Su-47 has extremely high agility at subsonic speeds enabling the aircraft to alter its angle of attack and its flight path very quickly, and it also retains manoeuvrability in supersonic flight.The Su-47 aircraft has very high levels of manoeuvrability with maintained stability and controllability at all angles of attack.
Maximum turn rates and the upper and lower limits on air speed for weapon launch are important criteria in terms of combat superiority in close combat and also at medium and long range, when the mission may involve engaging consecutive targets in different sectors of the airspace. A high turn rate of the Su-47 allows the pilot to turn the fighter aircraft quickly towards the next target to initiate the weapon launch.
"The Su-47 has extremely high agility at subsonic speeds."
The swept-forward wing, compared to a swept-back wing of the same area, provides a number of advantages: higher lift to drag ratio; higher capacity in dogfight manoeuvres; higher range at subsonic speed; improved stall resistance and anti-spin characteristics; improved stability at high angles of attack; a lower minimum flight speed; and a shorter take-off and landing distance.
Wings
The forward-swept midwing gives the unconventional (and characteristic) appearance of the Su-47, earning it the nickname of 'devil' and 'slingshot'. A substantial part of the lift generated by the forward-swept wing occurs at the inner portion of the wingspan. The lift is not restricted by wingtip stall. The ailerons - the wing's control surfaces - remain effective at the highest angles of attack, and controllability of the aircraft is retained even in the event of airflow separating from the remainder of the wings' surface.
The wing panels are constructed of nearly 90% composites. The forward-swept midwing has a high aspect ratio, which contributes to long-range performance. The leading-edge root extensions blend smoothly to the wing panels, which are fitted with deflectable slats on the leading edge; flaps and ailerons on the trailing edge. The all-moving and small-area trapezoidal canards are connected to the leading-edge root extensions.
The downside of such a wing design is that it produces strong rotational forces that try to twist the wings off, especially at high speeds. This twisting necessitates the use of a large amount of composites in order to increase the strength and durability of the wing. Despite this strengthening, the plane was initially limited to Mach 1.6. Recent engineering modifications have raised this limit, but the new limit has not been specified. Nevertheless, it is rumored that the Su-47 prototype recently suffered some manner of wing failure during testing. As a result, Western analysts speculate that Sukhoi engineers have restored the prototype to a conventional swept-wing layout. Apparently, the engineers reached the same conclusions with regard to the viability of a forward-swept layout as their counterparts at Grumman did twenty years ago with the X-29. Therefore, it is likely that any derivative production aircraft based on Su-47 research will utilize a conventional wing layout.
