Definition
The angle between the chord line of a propeller blade section and the propeller's plane of rotation. This angle determines how much air the blade slices into and pushes back with each revolution.
Plain English
The angle the propeller blade is set at as it spins. A steeper angle takes a bigger 'bite' of air; a flatter angle takes a smaller bite.
Context Anchor
Seen in propeller and P-factor discussions, especially when explaining why the descending blade can create more thrust than the ascending blade at a high nose-up attitude.
Derivation
Pitch' comes from older English use meaning the slope or angle at which something is set, the same sense used in 'roof pitch.' Applied to a propeller, it describes the slope of the blade relative to its rotation.
Why Pilots Care
Changes in effective blade pitch on the descending side of the propeller create extra thrust on that side, producing a left yaw force when the nose is raised.
Analogy
Think of a paddle in water. If you hold it nearly flat, it slips through easily; if you angle it more, it grabs more water and pushes harder. A propeller blade works in air in a similar way.
Intuition Check
Do not read pitch here as the airplane’s nose-up or nose-down attitude, or as the pitch of a sound. Here, pitch means the angle of the propeller blade as it turns.
Example Sentence 1
At a high angle of attack, the downgoing blade has a greater effective pitch than the upgoing blade, producing asymmetric thrust.
Example Sentence 2
Adjusting propeller controls changes the pitch of the blade to maintain efficient thrust across different flight speeds.