Definition
A propeller design in which the blade angle is set by the manufacturer and cannot be changed by the pilot in flight or on the ground. The propeller operates at one fixed blade angle, optimized for a single flight condition such as climb or cruise.
Plain English
The propeller blades are locked at one angle. The pilot cannot adjust them, so the propeller is built as a compromise that works reasonably well across all phases of flight but is never perfectly efficient in any one of them.
Context Anchor
Seen in light-sport aircraft descriptions, propeller limitations, and discussions comparing simple propellers with adjustable ones.
Derivation
Pitch' here refers to the angle of the propeller blade relative to its plane of rotation — similar to the pitch of a screw, which determines how far it advances per turn. 'Fixed' simply means it does not move. So 'fixed pitch' = the blade angle is permanently set.
Why Pilots Care
Fixed-pitch propellers are lighter, simpler, and cheaper than constant-speed designs, which suits most light-sport aircraft, but they give up some climb and cruise efficiency across varying conditions.
Analogy
Like a single-speed bicycle. It works fine, but you cannot shift gears to suit a steep hill or a flat road — you accept one compromise setting for all conditions.
Intuition Check
Fixed pitch does not mean the airplane’s nose attitude is fixed. Here, pitch means the propeller blade angle, and fixed means that angle is not changed in flight.
Example Sentence 1
The trainer was equipped with a fixed-pitch propeller, so the student managed engine power using throttle and RPM alone.
Example Sentence 2
During preflight the instructor pointed out the fixed pitch propeller blades and explained their constant angle.