Airfoil Anatomy
The straight line from an airfoil’s leading edge to trailing edge.
What is the chord line?
In the lift equation, this term represents air density.
What is ρ (rho)?
The angle between the chord line and the relative wind.
What is the AoA?
The front-most point of the airfoil where airflow first meets the wing.
What is the leading edge?
In the lift equation, this term represents wing reference area.
What is S?
The airflow pattern that typically causes a wing to lose lift rapidly.
What is flow separation?
The maximum distance between the upper and lower surfaces of an airfoil.
What is thickness?
This term is the dimensionless number that changes with angle of attack and airfoil shape.
What is CL, the coefficient of lift?
The AoA at which maximum CL occurs is commonly called this.
What is the critical angle of attack?
The curvature of an airfoil surface that strongly affects lift at low angles of attack.
What is camber?
If airspeed doubles and everything else stays the same, lift changes by this factor.
What is four times (4×)?
True/False clue: “Stalls happen only at low airspeeds.”
What is false? (Stall is primarily AoA-related.)
The point along the chord where the airfoil’s thickness is greatest (often expressed as a percent of chord).
What is the maximum thickness location?
This part of the equation—1/2ρV2—is called this.
What is dynamic pressure? (often written as q)
Wing design feature that helps the wing root stall before the tip to preserve aileron control.
What is wing washout? (twist reducing AoA at the tip)