Definition
The shape and outline of a wing as viewed from directly above or below. Planform describes characteristics such as wingspan, chord, taper, sweep, and overall geometric shape, all of which influence the wing's aerodynamic behavior, including lift distribution, stall characteristics, and induced drag.
Plain English
The shape of a wing when you look straight down at it from above. It tells you whether the wing is straight, swept back, tapered, rectangular, or some other shape.
Context Anchor
Seen in aerodynamics and lift discussions when comparing different wing shapes and how they affect aircraft performance.
Derivation
From 'plan' (a view from above, as in a floor plan or map) and 'form' (shape). A planform is literally the wing's shape as drawn on a flat plan view.
Why Pilots Care
Wing planform directly affects lift distribution, stall behavior, drag, and suitability for different flight speeds.
Intuition Check
Do not think of planform as the wing’s side profile or its airfoil shape. Planform means the top-down outline of the wing or surface.
Example Sentence 1
The Cessna 172 has a nearly rectangular planform, which contributes to its gentle stall behavior.
Example Sentence 2
A tapered planform reduces drag at the tips while maintaining good lift across the span.