L.: Aerodynamic Characteristics of Three Deep-Step Planing Tail Flying-Boat Hulls

An investigation was made to determine the aerodynamic characteris-tics in the presence of a wing of three deep-step planing-tail flying-boat hulls which differed only in the amount of step fairing. The hulls were derived by increasing the unfaired-step depth of a planing-tail hull of a previous aerodynamic investigation to a depth of about 92 per-cent of the hull beam. For the purpose of comparison, tests were also made of a transverse-step hull with an extended afterbody. The investigation indicated that the transverse-step hull with extended afterbody had about the same minimum drag coefficient, 0.0066, as a conventional hull and an angle-of-attack range for minimum drag of 3 ° to 5°. The hull with a deep unfaired step had a minimum drag coef-ficient of 0.0057} which was 14 percent less than the transverse-step hull with extended afterbody; the hulls with step fairing had up to kk percent less minimum drag coefficient than the transverse-step hull. Longitudinal and lateral instability varied little with step fairing and was about the same as for a conventional hull