The fin profile describes the cross-sectional shape of the fin with several parameters.
- The thickness/chord ratio of the fin is the thickness D expressed as the percentage of the chord S. If a fin is 8 mm thick and 8 cm wide, its relative thickness is 10 %.
- The position of the greatest thickness is described as the distance T of the maximum thickness from the leading edge N expressed as the percentage of the chord S. A standard percentage would be 30 %.
- The camber of the profile is the shape forward of and rear of the greatest thickness.
- The radius of the nose is the radius of leading edge.
- The trailing edge is the rear end of the fin profile.
The various cross sections are defined by the NACA sections (National Advisory Committee for Aeronautics). NACA 0012 for instance describes a profile with thickness/chord ratio 12 %.