“…4 Over a period of years this author has been collecting experience to show that the typical shock wave orientation at the leading edges of supersonic compressor rotor tips, with relative upstream Mach numbers in the range 1.4-1. 8, is not at Presented as Paper 79-0043 at the 17th Aerospace Sciences Meeting, New Orleans, La., Jan. [15][16][17]1979; submitted Feb. 13,1979 40-45 deg from the pressure surface, as would be predicted from conventional two-dimensional supersonic flow analysis, but rather is in the 60-70 deg range, corresponding roughly to maximum theoretical stream deflection and near-sonic downstream Mach number. Apparently, it is coincidental that this wave orientation usually appears to be perpendicular to the line through airfoil leading edges, within measurement resolution.…”