Foil bearing

The shaft and foil are separated by the air's high pressure, which is generated by the rotation that pulls gas into the bearing via viscosity effects.

The high speed of the shaft with respect to the foil is required to initiate the air gap, and once this has been achieved, no wear occurs.

[3] Garrett AiResearch air cycle machine foil bearings were first installed as original equipment in 1969 in the DC-10's environmental control systems.

[4] Current-generation foil bearings with advanced coatings have greatly exceeded the limitations of earlier designs.

[6] Commercial applications in production include microturbines,[7] fuel cell blowers,[8] and air cycle machines.

Foil-air bearing
A foil-air bearing for the core rotor shaft of an aircraft turbine engine.
Sectional diagram of a foil bearing, showing the component parts (inner, moving outwards) of the shaft journal, a smooth top foil, the bump foil (both foils joined) and finally the bearing housing
Foil Bearing
Graph of load capacity against speed for first and third generation bearings: The load is proportional to rotation speed, bearing length, and the square of shaft diameter. Third-generation bearings carry about three times as much load as first-generation ones.
Load capacity against rotation speed, for Gen I and Gen III bearings