Definition
The central component of a propeller that mounts to the engine crankshaft and holds the propeller blades in position. The hub transmits engine torque to the blades and, on variable-pitch propellers, contains the mechanism that changes blade angle.
Plain English
The middle part of a propeller. The blades attach to it, and it bolts onto the engine so the engine can turn the whole propeller as one unit.
Context Anchor
Seen in propeller inspection, propeller installation, and maintenance discussions about blade attachment, mounting bolts, cracks, and vibration.
Derivation
From Old English 'hubbe', meaning the central part of a wheel. The aviation use carries the same idea: the center point that everything else attaches to and rotates around.
Why Pilots Care
Improper hub condition or attachment can cause severe vibration, loss of propeller control, or blade separation in flight.
Analogy
Think of the hub as the center of a bicycle wheel: the spokes attach to it, and the whole wheel turns around it. On a propeller, the blades attach to the hub, and the propeller turns from that central point.
Intuition Check
Do not confuse this with an airline hub or a busy airport connection point. In this maintenance context, hub means the central physical part of the propeller assembly.
Example Sentence 1
During preflight, the pilot checked the propeller hub for oil leaks and visible cracks.
Example Sentence 2
Proper torque on the hub bolts prevents the propeller from loosening during flight.