An investigation was made to determine the aerodynamic characteristics of three deep-step (92 percent of beam) planing-tail flying-boat hulls differing only in the amount of step fairing and of a transverse-step hull with extended afterbody. Minimum drag coefficients, which include the interference effects of the support wing, were 0.0066 for the transverse-step hull - about the same as for a conventional hull - and 0.0057 or 14 percent less for the hull with a deep unfaired step. The hulls with step fairing had up to 44 percent less drag. Longitudinal and lateral stabilty was about the same as for a conventional hull.

An investigation was made to determine the aerodynamic characteristics of three planing-tail flying-boat hulls which differed only in the amount of step fairing. The hulls were derived by altering the step and afterbody of a conventional flying-boat hull having a transverse step.

An investigation was made to determine the reduction in drag that could be obtained for a conventional-type flying-boat hull by means of aerodynamic refinements. For comparisons, tests were made on a streamline body simulating the fuselage of a modern transport airplane.