Self-acting plain cylindrical journal bearing

Compressibility number, dimensionless stiffness and attitude angle for a self-acting (aerodynamic) plain cylindrical journal bearing — a specialist gas-bearing calculation with essentially no free equivalent anywhere.

✓ validated against legacyoriginal: /engineering-abc/calculators/e9_3d.htm
Compressibility number, Λ10.68
Dimensionless stiffness, S₁6.3
Bearing stiffness, S6.3 N/µm
Attitude angle, β18 deg

Valid for L/D up to 1.5 (the legacy tool clamps larger values). Plain (non-grooved) bore — see the spiral-groove journal bearing calculator for the grooved variant.


The computation is a literal port of the original client-side JavaScript from /engineering-abc/calculators/e9_3d.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.

Self-acting plain cylindrical journal bearing — Engineering ABC