Foil bearings offer levels of performance and efficiency unmatched by conventional bearings for high-speed machinery.  Ideally suited for use in hostile environments or oil-free systems, these bearings are more resilient and tolerant to misalignment than solid-pad gas bearings.  Foster-Miller's hydrodynamic (self-acting) compliant foil bearing generates its own load-carrying film from the rotation of the shaft it supports.  A smooth top foil forms the bearing surface, and a flexible "bump" foil provides this surface with controlled, resilient support.  This proprietary design ensures a "self-adjusting" bearing with inherent internal damping.  It adapts to shaft misalignment, variations due to tolerance buildups, centrifugal shaft growth, and differential thermal expansion.  Air-cycle machines, high-speed motors, and oil-free cryogenic compressors are among the many types of machinery that can use foil bearings.  Our project experience includes:

• Foil bearings and an active magnetic thrust bearing for a direct-drive compressor.
• Two small bump preloaded foil bearings for a vertical cryogenic helium compressor.
•  Fifty Generation I foil bearings for NASA.
• Prototype foil bearings for a miniature gas turbine engine used as an ultra-high-speed propulsion system for small ordnance.
• High-temperature (1,200ºF) foil bearings with life appropriate to man-rated and expendable engine applications.
• A foil gas bearing-rotor system for commercial cryogenic turboexpanders used for gas separation.
• Air-lubricated, compliant foil bearings for an automotive gas turbine engine.

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