Lehman and Kaplan 



4.00 



2.00 



Shaft Rate 13 rps 



1-Bladed Prop • 

 2-Bladed Prop A 



1-Bladed Prop Q 

 2-Bladed Prop □ 

 4-Bladed Prop o 



0.25 0.50 0.75 



Spacing/Propeller Diameter 



Fig. 19 - Comparison of axial induced appendage forces 

 for single- and multibladed, double -thickness propellers 

 with a symmetrical appendage 



from this one blade all induced forces associated with a propeller having a multi- 

 ple number of blades can be determining for engineering purposes. 



Effect of Appendage Thickness and Span 



The effect of appendage thickness and span on the induced appendage force 

 magnitude was also investigated for the case involving axial induced forces. For 

 these studies the test arrangement was as shown in Fig. 21. (The propellers 

 employed in this particular study and in the remainder of the discussion of ex- 

 periments were commercial outboard- motor propellers. They were two- and 

 three-bladed propellers, both having a diameter of 8 in. and a pitch of 6 in., and 

 are shown in Fig. 22.) The appendage span varied from one extending completely 

 across the tunnel test section (19.56 in.) to smaller spans of 14 and 8 in. 



190 



