CORRELATION OF AIRFOIL ICE FORMATIONS AND THEIR AERODYNAMIC EFFECTS WITH IMPINGEMENT AND FLIGHT CONDITIONS

An empirical equation is developed by which changes in drag coefficients due to ice formations on an NACA 65A004 airfoil may be calculated from known icing and flight conditions; this equation is then extended to include available data for other airfoils up to 15-percent thickness ratio. The correlation was obtained primarily by use of ice heights and ice angles measured on the 4-percent thick airfoil. The final equation, however, does not include the ice measurements, but relates changes in drag coefficients due to ice with the following variables: icing time, airspeed, air temperature, liquid-water content, cloud droplet-impingement efficiencies, airfoil chord, angles of attack, and leading-edge radius-of-curvature.

Changes in lift and pitching-moment coefficients due to ice oh an NACA 0011 airfoil are also related to the corresponding changes in drag coefficients; additional data on lift and pitching-moment changes due to ice are limited to the 65A004 airfoil, for which complex trends preclude a relationship within the scope of this paper.