Definition
A wing planform in which the leading and trailing edges are essentially parallel and the chord (front-to-back width) stays the same from the wing root to the wing tip. Because of this shape, a rectangular wing tends to stall at the root first, leaving the tips and ailerons flying for a moment longer, which gives gentle stall behavior and good low-speed handling.
Plain English
A wing shaped like a long rectangle when viewed from above, with the same width all the way out to the tip. This shape makes the airplane stall in a calm, predictable way and keeps roll control working a little longer as the stall develops.
Context Anchor
Seen in discussions of wing planform, especially when comparing how different wing shapes affect stall behavior, handling, and drag.
Derivation
Planform refers to the shape of the wing as seen from directly above. 'Rectangular' simply describes that planform: a rectangle, with parallel leading and trailing edges and a constant chord.
Why Pilots Care
Rectangular wings are simple to build, produce predictable stall progression from root to tip, and are common on basic training aircraft.
Intuition Check
Do not picture the wing as a thick three-dimensional box. In this context, rectangular describes the wing’s shape when viewed from above, mainly that its front-to-back width stays nearly constant from root to tip.
Example Sentence 1
The Cessna 172's rectangular wing is one reason it has such gentle, well-mannered stall behavior.
Example Sentence 2
Compared with tapered wings, the rectangular planform creates more induced drag near the tips but offers forgiving low-speed handling.