Definition
The straight-line distance from the root of a propeller or rotor blade to its tip, measured along the blade's longitudinal axis.
Plain English
How long a single blade is, measured from where it attaches at the hub out to its tip.
Context Anchor
Seen in propeller, rotor, and maintenance discussions when describing blade size, clearance, or damage location.
Derivation
Span comes from Old English spann, meaning the distance between two points. The same word is used for wingspan. Here it refers to the length of one blade from hub to tip.
Why Pilots Care
Determines the swept disk area that produces lift or thrust, directly affecting performance, efficiency, and structural loads.
Intuition Check
Blade span does not mean the full distance from one blade tip across to the opposite blade tip. It means the length of one blade only.
Example Sentence 1
The mechanic checked the blade span against the manufacturer's specification before reinstalling the propeller.
Example Sentence 2
A longer blade span increases lift but also raises centrifugal forces on the hub.