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Aviation glossary

Constant Speed Propeller

What is constant speed propeller?

Illustration related to constant speed propeller
Image: MKFI — Public domain, via Wikimedia Commons

A constant speed propeller is a controllable-pitch propeller whose blade angle is automatically adjusted in flight by a governor to maintain a constant engine rpm despite changing air loads. As airspeed or power changes, the governor increases or decreases blade pitch to hold the rpm you've selected with the propeller control. Think of it as cruise control for propeller rpm—you pick the rpm, and the governor does the work to keep it there.

Also known as: CSP, constant-speed prop, controllable-pitch propeller

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