Definition
A specific airfoil shape with a flat lower surface from about 30 percent of the chord back to the trailing edge, and a curved (cambered) upper surface. Designed in 1922 by Virginius E. Clark, it produces good lift with relatively low drag and is easy to manufacture because of its flat bottom. It has been widely used on general aviation, training, and historic aircraft.
Plain English
A wing cross-section shape with a flat bottom and a curved top. It is a classic, simple wing profile that flies well and is easy to build.
Context Anchor
Seen in airfoil design diagrams that compare different wing shapes and how they affect aircraft performance.
Derivation
Named after Virginius E. Clark, the U.S. Army officer and engineer who designed it. The 'Y' is simply the letter he assigned in his series of airfoil experiments — it has no separate meaning. Knowing this prevents the reader from looking for a hidden technical meaning in the letter.
Why Pilots Care
Many trainers and light aircraft use Clark Y or Clark-Y-derived wings, so the handling traits — gentle stall behavior, predictable lift — are common in primary training.
Grounding Statement
Picture slicing through a wing from front to back: the Clark 'Y' is the outline of that slice, with a curved top and a flatter bottom.
Intuition Check
Do not read "Y" as meaning the airfoil is Y-shaped. Here, "Clark 'Y'" is the name of a particular airfoil design.
Example Sentence 1
The Piper Cub uses a Clark Y airfoil, which contributes to its forgiving low-speed handling.
Example Sentence 2
The student compared the Clark 'Y' airfoil's stall behavior with a modern laminar-flow wing during preflight study.