Supercritical air-foil profile

Claim 1

An air-foil profile having a specific Mach design number not exceeding about 0.85 and a maximum profile thickness of about 0.13±20% in units of chord lengths, the profile having in each point a radius of curvature, the profile having separate maximum thicknesses respectively of an upper surface portion and of a lower surface portion relative to a chord line, the maximum thickness of the upper surface portion of the foil is at a 0.42 ±10% chord station; the maximum thickness of the lower surface portion is at an about 0.27 to an about 0.37 chord station; the surfaces having a curvature definded as the absolute inverse value of the radius of curvature, comprising the following features: the curvature of the upper surface is between 0.3 and 0.4 for a first minimum in a chord station range from 0.3 to 0.55; the curvature of the upper surface is about 0.4 for a relative maximum in a chord station range from 0.55 to 0.7; the curvature of the upper surface profile is about 0.2 for a second minimum at a chord station of about 0.9; a point of inflection in the curvature is located at a 0.5 to 0.6 chord station between the first minimum and the maximum; the curvature of the lower surface is larger than the curvature of the upper surface for chord stations smaller than and up to 0.55; the curvature of the lower surface is zero at a station from 0.6 to 0.7; and the curvature of the lower surface increases rearwardly from a zero value at a change in sign to a maximum of about 1.3 from which the curvature of the lower surface drops to zero at the trailing edge of the profile.