the forward-swept midwing gives the su-47 its unconventional appearance. a substantial part of the lift generated by the forward-swept wing occurs at the inner portion of the wingspan. this inboard lift is not restricted by wingtip stall and the lift-induced wingtip vortex generation is thus reduced. 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.