1972 · 44 citations · 0 references
EngineeringHighly Skewed PropellersAerospace EngineeringMechanical EngineeringPropeller AerodynamicsMechanical SystemsAerodynamicsRotor DynamicPropulsionAerospace Propulsion SystemsAerospace PropulsionSkewed TypeConventional PropellersSkewed Propellers
Theoretical and experimental data show that highly skewed propellers offer advantages and disadvantages compared with conventional ones, and careful skew selection is required to realize benefits. The study aims to aid propeller design by presenting correction factors for camber, loading, and thickness. The authors provide these correction factors for a limited series of highly skewed propellers. Highly skewed propellers reduce unsteady bearing and pressure forces, increase cavitation inception speeds, preserve ahead efficiency, only slightly reduce backing efficiency, and can be made strong enough despite complex strength characteristics.
Theoretical and experimental data are presented that show the advantages and disadvantages of highly skewed propellers compared with conventional propellers. The advantages, in general, are reduction in unsteady bearing forces and moments, reduction in unsteady pressure forces, and increased cavitation inception speeds. These advantages are shown to be achieved without an adverse effect on the ahead efficiency and with only a minor decrease in backing efficiency. However, care must be used in the selection of skew to insure that the potential benefits are realized. Although the strength characteristics of highly skewed propellers are considerably more complicated than for conventional propellers, it is shown that there is no problem in assuring the strength integrity of the highly skewed type. To aid in the design of these propellers, correction factors for camber, ideal angle due to loading, and ideal angle due to thickness are presented for a limited series.