Abstract: A tubular fibrous blanket is formed using a rotary fiberizer which produces a tow of substantially continuous thermoplastic fibers and a suction chamber with an annular, vertically extending, collection surface spaced from and surrounding the rotary fiberizer. The fibrous tow is collected on the annular, vertical collection surface or on a foraminous backing sheet passing over the collection surface in a spiral of very low pitch with succeeding portions of the tow at least partially overlapping and preferably, substantially completely overlapping preceding portions of the tow to form the tubular blanket. The tubular fibrous blanket and the backing sheet, when used, can then be slit longitudinally and unfolded to form a flat blanket having continuous fibers extending substantially perpendicular to the longitudinal axis of the blanket.