in 1951 a third national aerospace factory, wsk-świdnik, was built in świdnik, and in 1957 it was renamed to wsk pzl-świdnik. since 1956 it has become one of the world's major helicopter manufacturers, producing helicopters under the soviet licence, starting with the sm-1 (mil mi-1). świdnik was the main producer of the mi-1 and exclusive producer of the widely used in the world mil mi-2. since the late 1980s, świdnik has been producing a polish-designed medium helicopter pzl w-3 sokół. it also produces a light helicopter, the pzl sw-4 puszczyk. after 1991 the state factory became a state-owned corporation (wsk "pzl-świdnik" sa). it also produced the pirat, pw-5 and pw-6 gliders and cooperates widely with other nations' manufacturers, e.g., in the manufacture of agusta a109 fuselages.