MINIMUM PRESSURE ENVELOPES FOR MODIFIED NACA-66 SECTIONS WITH NACA A=0.8 CAMBER AND BUSHIPS TYPE 1 AND TYPE 2 SECTIONS

Minimum pressure envelopes, computed for steady two-dimensional flow, with an empirical correction for viscosity, are presented in graphic form for three foils: NACA 66 (TMB modified nose and tail) thickness with the NACA a = 0.8 camberline, the BuShips Type I section and the BuShips Type II section. In addition, design charts for selecting an 'optimum' foil are included. A comparison of these foils, designed to have a favorable operating range of minimum pressures for a specified cavitation number and lift coefficient, shows the 66 (modified) form to provide a slightly wider margin for angle changes. Also with zero camber, the 66 (modified) section has a greater range of favorable minimum pressures than the other foils.