Effects of Ice Formations on Airplane Performance in Level Cruising Flight

A flight investigation in natural icing conditions was conducted by the NACA to determine the effect of ice accretion on airplane performance. The maximum loss in propeller efficiency encountered due to ice formation on the propeller blades was 19 percent. During 87 percent of the propeller icing encounters, losses of 10 percent or less were observed. Ice formations on all of the components of the airplane except the propellers during one icing encounter resulted in an increase in parasite drag of the airplane of 81 percent. The control response of the airplane in this condition was marginal.