Patent ID: 6164918
Filing Date: 2000-12-26
Classification: B64C,Y10S

Abstract:
A helicopter blade aerofoil having coordinate values with .+-.3% errors of upper and lower surfaces on the basis of a reference aerofoil having a thickness to chord ratio of 5% to 11%, of which upper and lower surfaces are substantially defined by the following coordinates and of which a leading edge profile is substantially defined by the following leading edge radius and center of a circle: X/C Yup/C Ylow/C  0.00000 -0.00323 -0.00323 0.00100 0.00155 -0.00758 0.00250 0.00418 -0.00925 0.00500 0.00782 -0.01062 0.00750 0.01060 -0.01155 0.01000 0.01312 -0.01213 0.01750 0.01912 -0.01316 0.02500 0.02381 -0.01388 0.05000 0.03437 -0.01561 0.75000 0.04070 -0.01707 0.10000 0.04466 -0.01852 0.15000 0.04893 -0.02100 0.20000 0.05083 -0.02312 0.25000 0.05150 -0.02506 0.30000 0.05149 -0.02663 0.35000 0.05105 -0.02775 0.40000 0.05016 -0.02835 0.45000 0.04875 -0.02839 0.50000 0.04663 -0.02767 0.55000 0.04359 -0.02618 0.60000 0.03974 -0.02407 0.65000 0.03515 -0.02146 0.70000 0.03000 -0.01847 0.75000 0.02451 -0.01523 0.80000 0.01892 -0.01187 0.85000 0.01347 -0.00851 0.90000 0.00836 -0.00529 0.95000 0.00381 -0.00233 1.00000 0.00207 -0.00079  Leading edge radius r/C=0.01073,Center of circle X/C=0.01072, Y/C=-0.00373,where X is a distance from the leading edge to a trailing edge along a chord line, C is a length of the aerofoil in the chord direction, Yup is a distance from the chord line to the upper surface, Ylow is a distance from the chord line to the lower surface, and r is the leading edge radius.