Definition
A propeller whose blade angle (pitch) is set by the manufacturer and cannot be adjusted by the pilot in flight. Engine power and propeller efficiency are controlled solely through the throttle, which changes engine RPM. The blade angle is chosen as a compromise that performs reasonably across climb, cruise, and descent, but is not optimal for any single phase of flight.
Plain English
A propeller with blades locked at one fixed angle. The pilot cannot change how the blades bite the air — only how fast the engine spins them.
Context Anchor
You will see this term in propeller operation, engine performance, and anti-icing or deicing discussions, especially when comparing simple propeller systems with adjustable propeller systems.
Derivation
“Fixed” comes from a word meaning fastened or set in place. “Pitch,” in propeller use, means the blade’s angle as it bites into the air. “Propeller” comes from “propel,” meaning to drive forward. Together, the term points to a propeller that drives the airplane forward with a blade angle that is set in place.
Why Pilots Care
With a fixed-pitch propeller, the pilot has only one engine control to manage (the throttle), which simplifies operation. But it also means the propeller is never working at peak efficiency — climb performance, cruise speed, and fuel economy are all compromises rather than optimized settings.
Analogy
Think of a single-speed bicycle. You can pedal harder or softer, but you can't shift gears to better suit a hill or a flat road. A fixed-pitch propeller works the same way — one setting, used for everything.
Intuition Check
“Fixed” does not mean the propeller is stuck and cannot spin. It means the blade angle is fixed and cannot be changed in flight. “Pitch” here does not mean sound; it means blade angle.
Example Sentence 1
The training aircraft had a fixed-pitch propeller, so the student only needed to manage the throttle during climb and cruise.
Example Sentence 2
During preflight the pilot checks that the fixed-pitch propellers show no nicks or cracks along the leading edges.