Two-dimensional aerodynamic characteristics of an airfoil designed for two

An airfoil designed for helicopter rotor application is investigated. The airfoil is designed to increase maximum normal force coefficient while maintaining favorable drag divergence and pitching moment characteristics. Two modifications are also tested. Maximum normal force coefficient varies from 1.14 to 0.90 at Mach numbers from about 0.35 to 0.65. Both modifications decreased drag coefficient at zero normal force coefficient for Mach numbers near drag divergence, but were less beneficial at a normal force coefficient of -0.2.