A Computer Program for the Preliminary Design of Contrarotating Propellers
DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD SHIP PERFORMANCE DEPT
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This report presents a new computer program that can be used to design and predict the performance of contrarotating propellers. The new propeller utilizes the latest numerical computation techniques developed for the design of contrarotating propellers. The hydrodynamic pitch angle distribution is specified as input and the design calculations are made using Lerbs moderately loaded single screw lifting line propeller theory. The propeller interaction effects the most important new feature of the design procedure are obtained using Kerwins field point velocity program developed using finite bladed lifting surface theory. An analysis of results obtained for a sample set of contrarotating propellers, designed using the new method presented, show that different design and performance predictions are obtained for the aft propellers when results are compared to those calculated using the old method. Calculations made using the new design method are considered more accurate due to the improved method of determining the propeller interaction effects. A FORTRAN listing of the new propeller, developed to run on the computer at the David W. Taylor Naval Ship Research and Development Center DTNSRDC is presented as well as input and output obtained for a sample set of contrarotating propeller designs.
- Marine Engineering