Summary: A technical method is given for calculating the axial interference velocity of a propeller. The method involves the use of certain weight functions P, Q, and F. Numerical values for the weight functions are given for two-blade, three-blade, and six-blade propellers.

Summary: Values of the circulation function have been obtained for dual-rotating propellers. Numerical values are given for four-, eight-, and twelve-blade dual-rotating propellers and for advance ratios from 2 to about 6. In addition, the circulation function has been determined for single-rotating propellers for the higher values of the advance ratio. The mass coefficient, another quantity of significance in propeller theory, has been introduced. This mass coefficient, which is actually the mean value of the circulation coefficient, expresses the effective area of the column of the medium acted upon by the propeller in terms of the propeller-disk area. Values of the mass coefficient, which have been determined directly by special measurements and also by integration of the circulation function, are given for the four-, eight-, and twelve-blade dual-rotating propellers. The mass coefficient has also been determined for several cases of single-rotating propellers, partly for the purpose of comparing such experimental values with theoretical results in the known range of low advance ratios and partly to extend the results to include a range of high advance ratios. The effect of stationary countervanes on the mass coefficient has also been determined for several cases of practical interest.

Summary: As the conditions of the ultimate wake are of concern both theoretically and practically, the magnitude of the slipstream contraction has been calculated. It will be noted that the contraction in a representative case is of the order of only 1 percent of the propeller diameter. In consequence, all calculations need involve only first-order effects. Curves and tables are given for the contraction coefficient of two-blade and four-blade propellers for various values of the advance ratio; the contraction coefficient is defined as the contraction in the diameter of the wake helix in terms of the wake diameter at infinity. The contour lines of the wake helix are also shown at four values of the advance ratio in comparison with the contour lines for an infinite number of blades.

The early development of the screw propeller. Propeller geometry. The propeller environment. The ship wake field, propeller performance characteristics.