Definition
The blade angle selected by the pilot on a controllable-pitch or constant-speed propeller, which determines how much air each blade takes a 'bite' of with every revolution. On a constant-speed propeller, the pitch setting is selected indirectly by choosing an RPM with the propeller control; the governor then adjusts blade angle automatically to maintain that RPM.
Plain English
The angle the propeller blades are set to. A flatter angle takes a smaller bite of air and lets the engine spin faster; a steeper angle takes a bigger bite and slows the engine down while moving more air per turn.
Context Anchor
Seen in propeller operation, propeller control, and maintenance discussions, especially with adjustable-pitch or constant-speed propellers.
Derivation
Pitch' here comes from the same root as the pitch of a screw -- how far it would advance through a solid material in one full turn. A propeller blade works like a rotating wing, but the screw analogy is where the word comes from: a higher pitch setting means the blade would, in theory, pull the aircraft further forward per revolution.
Why Pilots Care
Pitch setting directly affects engine RPM, performance, and efficiency. A low (fine) pitch is used for takeoff and climb to allow high RPM and full power. A high (coarse) pitch is used for cruise to move more air per revolution at lower RPM, similar to shifting into a higher gear.
Analogy
Think of it like the gears on a bicycle. A low pitch is like a low gear -- easy to spin fast, good for getting moving. A high pitch is like a high gear -- harder to turn, but you cover more ground with each pedal stroke.
Intuition Check
“Pitch” here does not mean the airplane’s nose-up or nose-down attitude. It means the angle setting of the propeller blades.
Example Sentence 1
For takeoff, the pilot selected a low pitch setting to allow the engine to develop full RPM and maximum power.
Example Sentence 2
During cruise the constant-speed unit automatically changed the pitch setting to hold the chosen RPM.