How is wing aspect ratio defined?

How is wing aspect ratio defined?

• A. Wingspan divided by mean chord
• B. Wingspan divided by wing area
• C. Mean chord divided by wingspan
• D. Wing area divided by mean chord

Answer: (A)

Aspect ratio measures how slender a wing is by relating its span to a representative width. The standard definition uses the wingspan squared divided by the wing area, but since the wing’s mean chord c̄ is defined so that S = b · c̄, the ratio can also be written as AR = b / c̄. In other words, aspect ratio is the wingspan divided by the mean chord (mean aerodynamic chord). This form works for any planform, not just rectangles, because c̄ is the average chord across the span weighted by area. The other forms mix different quantities (like area) or flip the ratio, which doesn’t reflect the wing’s slenderness in the same way.

Aspect ratio measures how slender a wing is by relating its span to a representative width. The standard definition uses the wingspan squared divided by the wing area, but since the wing’s mean chord c̄ is defined so that S = b · c̄, the ratio can also be written as AR = b / c̄. In other words, aspect ratio is the wingspan divided by the mean chord (mean aerodynamic chord). This form works for any planform, not just rectangles, because c̄ is the average chord across the span weighted by area. The other forms mix different quantities (like area) or flip the ratio, which doesn’t reflect the wing’s slenderness in the same way.