Theory of the Ducted Propeller— A Review 



160. Kriebel, A.R., "Theoretical Investigation of Static Coefficients, Stability 

 Derivatives and Interference for Ducted-Propellers," Vidya Research and 

 Development, Palo Alto, Calif., Vidya Report No. 112 (1964) 



161. Kriebel, A.R., "Interference between a Hull and a Stern-Mounted Ducted 

 Propeller," Vidya Research and Development, Palo Alto, Calif., Vidya Re- 

 port No. 161 (1964) 



162. Kriebel, A.R., and Mendenhall, M.R., "Interference Between a Hull and a 

 Stern-Mounted Ducted Propeller," Vidya Report 204 (Oct. 1965) 



163. Kriebel, A.R., and Mendenhall, M.R., "Predicted and Measured Perform- 

 ance of Two Full-Scale Ducted Propellers," ITEK Corporation, Palo Alto, 

 Calif, (prepared for Ames Research Center), NASA Contractor Report 578 

 (Sept. 1966) , , . ,. 



164. Mendenhall, M.R., Kriebel, A.R., and Spangier, S.B., "Theoretical Study of 

 Ducted Propeller Blade Loading, Duct Stall, and Interference," Vidya Re- 

 port 229 (Sept. 1966) 



Addendum ' • r^:, .: 



Worobel, R,, and Peracchio, A. A., "Shrouded Propeller Test Program 

 Method Development," Hamilton Standard Engineering Report No. HSER 

 4776, Jan. 1968 ....■•;. - :- , - 



DISCUSSION 



Gilbert Dyne 

 The Swedish State Shipbuilding Experimental Tank 

 Gothenburg, Sweden ... 



The authors are to be commended for giving a very systematic and thorough 

 review of the theories of ducted propellers, within the limitations imposed. I 

 would, however, like to make some comments concerning some details of the 

 theories described. 



In all theories reviewed by the authors, the duct shape (or the source and 

 vortex distributions of the duct) is determined by satisfying the boundary condi- 

 tion at the duct. When we started to design ducted propellers six years ago at 

 the tank in Gothenburg, we also used this method. After some time, however, 

 we discovered, that the boundary -condition method in some cases could lead to 

 very unrealistic results. This was especially true for heavily loaded ducted 

 propellers, when the slipstream deviated from the cylindrical form, and the 

 blade circulation was zero at the blade tips. The reason was found to be that a 



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