Complex sentence: The wings had rounded ends and the outer pair of interplane struts fabric-covered to form voisin-style side curtains and an undercarriage with a pair of mainwheels mounted on trailing arms below the skids.
Split into simpler sentences: The wings had rounded ends and the outer pair of interplane struts were fabric covered to form voisin-style side curtains. The undercarriage was also of Voisin pattern, with a pair of mainwheels mounted on trailing arms below the skids.