19 



0.8 



0.2 



-04 



-06 



< 



I 











o Electrolytic Tank Date 

 D Water Tunnel Date 



\ 



















L 











Profile of Torpedo Model H-60 

















A 



















A 



















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) 





/ 



="« 



o" 



^_o_- 





□ 





\ 



/ 



/ 















a 



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0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 



x/b 



Figure 11 - Pressure Disbribution About Torpedo Model H-60 



The velocity and pressure distributions obtained about model H-60 are shown in Fig- 

 ures 10 and 11 and tabulated in Table 1. The experimental pressure measurements made with 

 piezometer openings in a model tested in the water tunnel are also shown in Figure 11. It is 

 seen that the pressures obtained in the electrolytic tank are consistently higher than those ob- 

 tained in the water tunnel. This discrepancy is believed to be caused by errors in machining 

 the model. The curve of Figure 12 is drawn from the actual offsets of the wax electrolytic 

 tank model while the correct offsets are indicated by circles. The two sets of offsets are 

 drawn to be coincident at the nose. It is seen that the offsets from the electrolytic tank model 

 do not fair into the straight section as fast as they should. If the forward part of the body may 

 be represented by a prolate spheriod, the error increases the effective semimajor axis and the 

 eccentricity. 



The method of computing the error in pressure coefficient from changes in eccentricity 

 of a prolate ellipsoid is described in Appendix B. If the method is applied to compute the 

 change in semimajor axis necessary to give the observed change in minimum pressure coef- 

 ficient, the semimajor axis would have to increase about 10 percent. As this is the right order 

 of magnitude for the increase in the semimajor axis, the observed pressure distribution appears 

 to be consistent. 



The irregularity in the pressure distribution for x/h between Ll'and 1.7 may be accoun- 

 ted for by a small surface irregularity in this region. 



