Researchers at Aachen University simulated the weft insertion process on air jet looms. A computer controlled air jet loom permitted measurements of yarn tension, air flow status, operating pressures, and yarn velocities during insertion of viscose, cotton/polyester, polyester, woolen, and filament yarns. A regression analysis of data derived simulation equations that identified relationships between yarn tension, yarn properties, and the air flow characteristics of the venturi tube of the main air jet.