This paper presents a new direction for improving the stability in externally pressurized, air lubricated journal bearings. To increase whirl threshold speed we locally changed supply pressure in cylindrical bearing instead of bearing shapes. Supply regions of bearing are divided six. There are four test shafts, each clearance is 118.5㎛, 97.5㎛, 79.5㎛, 59.5㎛.
In order to obtain the distribution of supply pressure which improves the stability, supply pressure are restricted to the value that maximum pressure is 0.4MPa, and step of pressure change 0.1MPa.
Under the restricted supply pressure, the prominent results are that the distribution of supply pressure for improving the stability is similar to 2-lobe bearings un relatively to clearances, moreover, the stability are improved from 30% to 85% depending on the clearances.
