Propeller -Induced Appendage Forces 



.02 H 



.01 . 

 .008 



.006 

 X 



^ u2wR2 

 .004 



.003 

 .002 



,001. 



Vr 



,05 



vorticity 



thickness 



,10 



.15 



,20 



Fig. 48 - Blade -rate axial force as a function of the spacing 

 distance for a two-bladed propeller: J = 1.0, N = 2, m = 1, 

 tn/2c = 0.10 -jc •■.■J/ •,■ ,. ..=■ ; .■ ;, 



spacing distance between the propeller and the appendage does not depend on J, 

 the same results hold true for other spacings. 



SUMMARY OF THEORETICAL RESULTS 



The various conclusions obtained from the theory are summarized in the 

 following. 



1. The induced appendage forces occur only at blade- rate and higher har- 

 monic frequencies. 



2. The number of blades and whether they are odd or even determines the 

 nature of the induced appendage forces; even-bladed propellers produce axial 



223 



