Definition
The angle between the chord line of a propeller blade and the propeller's plane of rotation, measured at a specified point along the blade. Blade pitch determines how big a 'bite' of air each blade takes as the propeller spins, which in turn affects thrust, engine load, and rpm.
Plain English
How steeply the propeller blades are angled into the oncoming air. A flatter angle takes a small bite of air; a steeper angle takes a big bite.
Context Anchor
Seen in constant-speed propeller discussions, especially when comparing low pitch for takeoff and climb with higher pitch for cruise.
Derivation
Pitch' here borrows from screw and ship-propeller terminology, where pitch describes how far one full turn would advance the screw through a solid material. A propeller blade with more pitch would, in theory, pull the airplane forward a greater distance per revolution.
Why Pilots Care
Correct blade pitch keeps engine RPM in the safe and efficient range and prevents overspeed damage or loss of thrust.
Analogy
Think of it like the gears on a bicycle. A low (flat) pitch is like a low gear -- easy to spin, lots of rpm, but you don't cover much ground per pedal stroke. A high (steep) pitch is like a high gear -- harder to turn, but each rotation moves you farther.
Intuition Check
Pitch here does not mean the airplane’s nose-up or nose-down attitude. In this term, pitch means the propeller blade’s angle setting and the amount of forward movement it is trying to produce with each turn.
Example Sentence 1
On a constant-speed propeller, the governor adjusts blade pitch automatically to hold the selected rpm as airspeed and power change.
Example Sentence 2
In cruise the pilot selected a coarser blade pitch to let the engine run at a lower, more efficient RPM.