The objective of this project is to develop a physics-based pneumatic hammer instability model that accurately predicts the stability of hydrostatic bearings operating in a turbulent, compressible fluid. In phase 2, the rig will be fabricated and assembled, design of experiment will be executed. The empirical data will be used to determine if a particular variable, or input parameter, was a contributor to pneumatic hammer instability. If not, the variable is eliminated. If the variable is determined to be a contributor, it is non-dimensionalized and included in the equations of motion to develop a physics-based stability criteria. The resulting criteria will then be validated using test data. If the criteria is not validated, a gap assessment will be completed and the process is repeated. Once the criteria is validated, it is implemented.