high die swell when the fiber cross sections were examined with an optical microscope the 0 69 i v fibers swelled to a point that they were no longer trilobal in shape and resembled delta cross sections they also had relatively low tenacity 0 88 i v poly trimethylene terephthalate was extruded into 72 filaments having trilobal cross section using a fiber spinning machine having take up and drawing configurations as in example 1 spin finish was applied as in example 1 extrusion and drawing conditions were as follows it was observed during spinning and drawing that when the first stage draw ratio between rolls 2 and 3 was less than about 1 5 as in runs 5 and 6 there were fewer broken filaments and the tenacities of the filaments were generally higher than when first stage draw was higher than about 1 5 when the first stage draw was increased to greater than 3 runs 7 8 9 10 and 11 it was observed that the fibers had a white streaky appearance the threadlines were loopy and there were frequent filament wraps on the draw rolls the process was frequently interrupted with fiber breaks the extrusion conditions in this experiment were the same as in example 2 the fibers were spun drawn and wound as in example 1 they were then textured by heating the fibers on a feed roll and exposing the fibers to a hot air jet the textured fibers were collected as a continuous plug on a jet screen cooling drum partial vacuum was applied to the drum to pull the ambient air to cool the yarns and keep them on the drum until they were wound the yarns were air entangled between the drum and the winder the feed roll and texturizer air jet.