Definition
The cross-sectional shape of a wing, propeller blade, or other airfoil when viewed from the side, showing the curvature of the upper and lower surfaces from leading edge to trailing edge. The profile determines how the airfoil produces lift and drag at a given speed and angle of attack.
Plain English
If you sliced through a wing from front to back and looked at the cut end, the shape you would see is the airfoil profile. Different shapes give the wing different flying characteristics.
Context Anchor
Seen in discussions of wing design, lift, drag, stalls, and why different aircraft wings are shaped differently.
Derivation
‘Airfoil’ combines ‘air’ with ‘foil’ (from Old French ‘foille’, meaning leaf or thin sheet). ‘Profile’ comes from Italian ‘profilo’, meaning a side view or outline. Together: the side-view outline of a surface that interacts with air.
Why Pilots Care
The profile sets the wing's lift-to-drag ratio, stall speed, and overall handling qualities that affect safety and efficiency.
Intuition Check
Do not read profile here as a personal description or a general summary. In airfoil profile, profile means the actual side-view shape of the wing or blade cross-section.
Example Sentence 1
The Cessna 172 uses a thick airfoil profile that gives it gentle stall behavior and good low-speed lift.
Example Sentence 2
Designers select a different airfoil profile to improve cruise efficiency on a new light aircraft.