Propeller -Induced Appendage Forces 



6.0 



Open Symbols = 1st Harmonic 

 Solid Symbols = 2nd Harmonic 



0.2 0.4 0.6 0.8 



Spacing/Propeller Diameter 



Fig. Z5 - Induced force ratio vs spacing ratio for a 

 two-bladed propeller downstream of an appendage, 

 axial measurements, and an appendage angle of 10° 



attack of 10°. With a three- bladed propeller, the axial induced force is essen- 

 tially zero when the appendage attack angle is zero, but with an appendage attack 

 angle of 10° the induced force becomes significant. Data supporting this result 

 are shown in Fig. 30. 



Rudder Case 



A few cases involving the unsteady forces induced on an appendage down- 

 stream of a propeller, i.e., the rudder case, are presented in this discussion to 

 illustrate the complexity of the unsteady propeller induced forces for the ar- 

 rangement. At the time of this reporting, only some initial studies have been 

 completed, but additional studies are being carried out. 



195 



