Which term describes the lower shape of an airfoil?

Which term describes the lower shape of an airfoil?

• A. Leading edge
• B. Camber line
• C. Lower camber
• D. Trailing edge

Answer: (C)

In airfoil geometry, the bottom boundary is the lower surface, not a special term like “lower camber.” Camber is the amount and direction of curvature of the airfoil, and it’s described by the camber line—the mean curve from the leading edge to the trailing edge that lies halfway between the upper and lower surfaces. The camber line defines how the airfoil’s thickness is distributed relative to the chord, but it isn’t the shape of the bottom surface itself. So, describing the lower boundary as “lower camber” isn’t standard terminology. If you’re talking about the bottom shape, you’d call it the lower surface; if you’re talking about the line that represents the mean curvature, you’d use the camber line. The other terms—leading edge and trailing edge—refer to the front and rear points of the chord, not the bottom boundary.

In airfoil geometry, the bottom boundary is the lower surface, not a special term like “lower camber.” Camber is the amount and direction of curvature of the airfoil, and it’s described by the camber line—the mean curve from the leading edge to the trailing edge that lies halfway between the upper and lower surfaces. The camber line defines how the airfoil’s thickness is distributed relative to the chord, but it isn’t the shape of the bottom surface itself.

So, describing the lower boundary as “lower camber” isn’t standard terminology. If you’re talking about the bottom shape, you’d call it the lower surface; if you’re talking about the line that represents the mean curvature, you’d use the camber line. The other terms—leading edge and trailing edge—refer to the front and rear points of the chord, not the bottom boundary.