Definition
A cross-sectional shape of a propeller blade taken at a specific point along its length, revealing an airfoil profile similar to that of a wing. Each blade section has its own chord line, thickness, camber, and angle relative to the plane of rotation, and these characteristics typically change from the hub to the tip.
Plain English
If you sliced through a propeller blade at any point and looked at the cut end, the shape you would see is a blade section. It looks like a small wing, and its shape varies depending on where along the blade you make the cut.
Context Anchor
Seen in propeller descriptions, maintenance manuals, and discussions of propeller blade shape, twist, and damage.
Derivation
‘Section’ comes from the Latin sectio, meaning ‘a cutting.’ A blade section is literally the shape revealed by cutting through the blade — the same idea as a cross-section in any engineering drawing.
Why Pilots Care
The airfoil shape of each blade section determines how much thrust the propeller produces and how it behaves at different speeds and power settings.
Analogy
Think of slicing a loaf of bread. Each slice shows the shape of the loaf at that spot; a blade section shows the shape of the propeller blade at one spot.
Intuition Check
Do not read “section” as a removable piece of the blade. Here it means an imaginary slice through the blade at one location.
Example Sentence 1
The blade section near the tip is thinner and set at a smaller angle than the section near the hub.
Example Sentence 2
A nick in the blade section can change its airfoil shape and reduce efficiency.