Definition
A bearing designed to absorb axial loads — forces acting along the length of a shaft rather than across it. In aircraft applications, thrust bearings are used wherever a rotating component pushes or pulls along its own axis, such as the propeller shaft of a piston engine or the main shafts of a turbine engine, where they hold the rotating assembly in position against the forward thrust load.
Plain English
A special bearing that handles pushing or pulling forces along a shaft, rather than the side-to-side spinning forces a normal bearing handles. It keeps a spinning shaft from sliding forward or backward.
Context Anchor
Seen in aircraft engine, propeller, gearbox, and maintenance discussions where rotating parts create a push along the shaft.
Derivation
Thrust here means a pushing force along an axis. The word bearing comes from 'to bear,' meaning to carry or support a load. Together: a bearing that carries a pushing load.
Why Pilots Care
It prevents axial movement that would damage engine components or reduce propeller efficiency.
Analogy
A regular wheel bearing mainly helps a wheel spin smoothly. A thrust bearing is more like a support that also resists someone pushing the spinning wheel straight inward or outward.
Intuition Check
Do not think of “thrust” here as engine power in general. Here it means a push along the shaft that the bearing must support.
Example Sentence 1
The propeller's pulling force is transferred to the airframe through the crankshaft thrust bearing.
Example Sentence 2
The new crankshaft assembly included an upgraded thrust bearing to handle higher power settings.