Boundary-layer computations on rotating blades 

 performed by Groves (27) utilize output from the computer 

 code described heiein In particular, the pressure distribu- 

 tion, streamline locations, and surface metrics (see Appendix) 

 are input data for the boundary-layer computations. 



CONCLUDING REMARKS 



Procedures have been described for determining 

 mean line and pitch distributions corresponding to a pre- 

 scribed load distribution. Computer run times are as great 

 as 20 minutes on the DTNSRDC Burroughs 7700 high-speed 

 computer. Computed meanline and pitch distributions are 

 dependent upon blade mid-chord location and chordwise 

 variation of load distribution, with negligible effect due to 

 chordwise variation of thickness distribution. A radial 

 inflow component was found to have a significant effect on 

 the design pitch of the blades. 



Calculated pressure distributions are dependent upon 

 blade rake and skew and both chordwise load distribution 

 and chordwise thickness distribution. Overall performance 

 coefficients calculated from second-order effects show 

 significant differences compared to lifting-line predictions 

 for highly-skewed and warped blades. Experimental con- 

 firmation of the predictions is required to evaluate these 

 second-order modifications of a first-order theory. 



Suggestions have been given for improving the pro- 

 cedures for calculating design geometry. Some of these 

 suggestions involve an improved mathematical model of the 

 flow field and some are improvements to the numerical 

 analysis techniques. 



ACKNOWLEDGEMENTS 



The development of the numerical analysis pro- 

 cedures for lifting-surface design was initiated while the 

 author was an Exchange Scientist at the Defence Research 

 Establishment Atlantic, Dartmouth, Nova Scotia and 

 completed at DTNSRDC under work unit 1 500- 1 04, Task 

 Area SF43421001, Program element 62543N. The help of 

 Ms. K. Tymchuk and Mr. R. Brian of the DREA staff and 

 Ms. J. Libby of the DTNSRDC staff has been essential to 

 completion of this task. 



REFERENCES 



1 . R. A. Cumming and Wm. B. Morgan. "Propeller Design 



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 1974. 



2. G. G. Cox and Wm. B. Morgan, "The Use of Theory in 



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3. E. B. Caster, et al, "A Lifting-Line Computer Program 



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4 T E. Brockett, "A Lifting-Line Computer Program 



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7. J. E. Kerwin, "Computer Techniques for Propeller 



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8. J. F. McMahon, "LFTSUR - A Computer Program for 



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9. Terry Brockett, "Propeller Perturbation Problems," 



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18. Terry Brockett, "The Design of Two-Dimensional 



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1 9. 1. H. Abbott, and A. E. von Doenhoff, Theory of Wing 



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20. W. F. Lindsey, et al, "Aerodynamic Characteristics of 



24 NACA-16 Series Airfoils at Mach Numbers 

 between 0.3 and 0.8," NACA TN 1546, September, 

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21. H. P. Rader, "Cavitation of Propeller Blade Sections," 



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22. Terry Brockett, "Minimum Pressure Envelopes for 



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23. J. J. Nelka, "Experimental Evaluations of a Series of 



Skewed Propellers with Forward Rake," NSRDC 

 Report 4113, July, 1974. 



20 



