Definition
A curved, swept-back propeller blade shape in which the leading edge sweeps rearward toward the tip in a smooth arc, resembling the curved blade of a scimitar sword. This planform is used on modern propellers to delay the onset of compressibility effects and reduce noise at high tip speeds.
Plain English
A propeller blade shape that curves backward toward the tip, like a curved sword. The shape lets the propeller spin faster without losing efficiency or making as much noise.
Context Anchor
Seen in powerplant and propeller discussions, especially when identifying propeller blade design or describing blade appearance during inspection.
Derivation
From the scimitar — a curved, single-edged sword used historically in the Middle East and South Asia. The blade's distinctive sweeping curve is what the propeller shape is named after. Knowing the sword shape immediately tells you what the blade looks like.
Why Pilots Care
Scimitar-shaped blades reduce noise, vibration, and drag while allowing higher cruise speeds with better fuel efficiency.
Intuition Check
Do not read “scimitar shape” as meaning the blade is damaged or warped. Here it means an intentional curved, swept-back blade design.
Example Sentence 1
The new turboprop featured scimitar-shaped propeller blades to improve high-speed performance and reduce noise.
Example Sentence 2
Scimitar shape blades require careful balancing during installation to avoid vibration at high RPM.