Lehman and Kaplan 



An example of the results obtained from the present theory is shown in 

 Fig. 40 for the fundamental blade rate transverse force on an appendage for a 

 three-bladed propeller, at a spacing corresponding to /? = 0.05. The total force 

 amplitude and the separate contributions of the propeller loading (vorticity) and 

 propeller thickness amplitudes, assuming each acted separately, are shown in 

 this figure, and no phase information between the vorticity and thickness terms 

 is given. The force is nondimensionalized on the basis of forward speed and 

 propeller disk area (,cU^7trV2) and plotted as a function of the advance ratio J. 

 Since the thrust coefficient Cj is defined in the same way, the ratio of the in- 

 duced force to the propeller thrust can be obtained to compare with experimental 

 data presented in that manner. 



14n 



.12 



,10- 



,08- 



I u2TrR2 



.06- 



.04- 



,02 



total 



vorticity 



thickness 



A- 



1.0 



1.2 



1.4 



Fig. 40 - Transverse force as a function of the advance ratio 

 for a three-bladed propeller, shovi^ing the influence of the 

 propeller thickness and loading (vorticity): p = 0.05, N = 3, 

 tn/2c = 0.05 



216 



