English: Two different and incompatible definitions of
airfoil thickness are used in the aerodynamics field (here illustrated on the same airfoil).
- In case A above the thickness is measured perpendicular to the foil camber line. This is sometimes described as the "American convention"[1] and can be seen in Houghton & Carpenter 2003,[1] Phillips 2010.[2]
- In case B above the thickness is measured perpendicular to the foil chord line. This is sometimes described as the "British convention" and can be seen in Bertin & Cummings 2009[3].
Note that each definition implies a different camber line geometry for a given airfoil. Since the camber line curvature is small on most aircraft, the effect of difference between the definitions is often small.
- ↑ a b Houghton, E. L.; Carpenter, P.W. (2003) Butterworth Heinmann , ed. Aerodynamics for Engineering Students (5th ed.) ISBN: 0750651113. p.17
- ↑ Phillips, Warren F. (2010) Mechanics of Flight (2nd ed.), Wiley & Sons ISBN: 9780470539750. p.27
- ↑ Bertin, John J.; Cummings, Russel M. (2009) Pearson Prentice Hall , ed. Aerodynamics for Engineers (5th ed.) ISBN: 9780132272681. p.199