Propeller -Induced Appendage Forces 



Excitation Voltage 



5.2 Volts ac at 20 K.C. 



Horizontal Bridges Wired for Summing 



Excitation Voltage 



5.2 Volts ac at 20 K.C. 



Vertical Bridges Wired for Summing 



Fig. 5 - Schematic of balance 

 gages wired for summing 



bars themselves are covered with streamlined fairings fastened to the tunnel 

 wall, thus preventing water flow forces from influencing the measured append- 

 age forces. However, it should be pointed out that the propeller is operating in 

 the wake of a cruciform appendage arrangement with measurements made only 

 on the vertical appendage. 



Asymmetry of the appendage was introduced by adding extensions to one 

 semispan of the basic symmetrical appendage. The basic appendage had an 

 ogival cross section with a chord of 8 in., a span of 8 in., and a maximum thick- 

 ness of 1 in. The basic appendage extended 1/2 propeller diameter; i.e., 4 in., 

 to either side of the propeller center line. Extensions having a span of 2 in. 

 were then added to one semispan of the basic appendage to produce the desired 



175 



