Application of transonic area rule to a sharp-lipped ducted nacelle

IN The transonic area rule has been used to determine the equivalent area distributions of two normal-shock, sharp-lipped inlet configurations. Two bodies of revolution having the longitudinal area distributions of the inlet configurations less the areas of the entering free-stream tubes have been flight-tested. The agreement between the measured transonic drag rise from tests of the inlet models and of the bodies of revolution confirmed the method of application of the rule in these cases. INTRODUCTION The transonic area rule of reference 1 states that the zero-lift transonic drag rise of an aircraft configuration is mainly a function of the axial distribution of cross-sectional area normal to the air stream. Previous investigations of the transonic area rule have shown the rule to predict the transonic drag rise of various aircraft configurations as reported in references 2 and