Air jet driving and supporting devices were tested for a high speed open-end spinning frame . Two types of rotors were prepared : the upper fluting rotor and the under fluting rotor. Each rotor was driven by air jet impinging upon the fluting directly from the nozzles prepared on the inner surfaces of a stator. The rotor was supported on its under conical surface by the dynamic pressure of air thrown down by the upper flutings or of the air jet itself on the under flutings. Series of tests were made for both types of the rotors, changing their conical angles, number and angle of the flutings, and driving air pressure. The results were as follows.
(1) The speed of rotor increased with increasing driving air pressure and reached the limit of speed quickly.
(2) The rotor conical angle 108°was suitable for the upper fluting mechanism, and 102°was suitable for the under fluting mechanism, with a fixed stator conical angle 92°.
(3) The number of flutings was suitable around 40 for the upper fluting mechanism, and 20 for the under fluting mechanism.
(4) The fluting angle influenced considerably to the driving torque, the fluting angle 45° and 25°was suitable respectively for the upper fluting and the under fluting mechanism.