Definition
The variation in blade angle along the length of a propeller blade, where the pitch (blade angle) is greater near the hub and progressively smaller toward the tip. This twist is built into the blade so that every section of the blade meets the oncoming air at an efficient angle, even though the tip travels much faster through the air than the root.
Plain English
The blade of a propeller is twisted along its length. It's set at a steeper angle near the center and a flatter angle near the tip. This twist is called pitch distribution.
Context Anchor
Seen in propeller design, propeller inspection, and aviation maintenance discussions.
Derivation
‘Pitch’ comes from the same idea used in screws — how far one full turn would advance the blade through the air. ‘Distribution’ here just means how that pitch is spread out along the blade, not held at a single value.
Why Pilots Care
A propeller works efficiently only because of this built-in twist. If a blade is bent, repaired incorrectly, or worn unevenly, the pitch distribution can change and the propeller will lose efficiency or vibrate.
Analogy
It is like twisting a fan blade so each part of the blade can move air properly, even though the tip is moving faster than the part near the center.
Intuition Check
Pitch here does not mean the aircraft’s nose-up or nose-down attitude. In this term, pitch means the angle of a propeller blade section as it meets the air.
Example Sentence 1
The technician checked the blade for damage that could alter its pitch distribution.
Example Sentence 2
Uneven pitch distribution can reduce propeller efficiency and create vibration during flight.