Definition
The pattern of how lift is produced along the length of a wing from root to tip. Lift is not generated uniformly across the span; it varies at each point along the wing, typically being greater near the root and tapering off toward the tip. The shape of this distribution depends on wing planform, airfoil, angle of attack, and proximity to the ground.
Plain English
How much lift each section of the wing is producing, from where the wing meets the fuselage all the way out to the wingtip. Some parts of the wing carry more of the load than others.
Context Anchor
Seen in discussions of wing behavior near the ground, especially how ground effect changes airflow and lift close to the runway.
Derivation
‘Spanwise’ means ‘along the span’ — the span being the distance from one wingtip to the other. So spanwise lift distribution simply describes how lift is spread out along that span.
Why Pilots Care
It determines induced drag and how ground effect changes handling near the runway.
Grounding Statement
Picture the wing as many small sections lined up from root to tip, with each section carrying part of the airplane’s weight.
Intuition Check
Do not read “distribution” as the total amount of lift. Here it means where along the wing the lift is being produced, and how much each part contributes.
Example Sentence 1
In ground effect, the spanwise lift distribution shifts because the wingtip vortices are reduced, allowing the wing to produce lift more efficiently.
Example Sentence 2
Ground effect reduces the outward flow at the tips and therefore alters the spanwise lift distribution.