MULE KNGINEK* 157 



!cr It requires 



IN much pressure to tear the ends out of a 

 .IN it <!<> t<> hurst the shell, and as the weakest 



<e safe pressure, we 

 \\ill ni.ik the she- 



ll take 'uler 3.' inches in 



tt. long, -Mi inch tl strength 



6o.OOO Ihs. Tin- total pressure re., this 



shell \\-uill IN- the area exposed times the pressure. The 

 multiple! l.\ the length, then by 2 (as there 



ngth equals the 

 ' O.OOO = 3,240,000. 



I IK- f-.t t! liui-nng- pressure ami tlie pressure per square 

 ImrM the shell is f>un ! ^ the 



'.OOO por. h: meter 



40.000 -r- ( ; = 1406 Ibs. 



ft \\iwM reijuirc 1406 llw. per square inch to l 

 >lu-ll if it were ; no seam. .1 



'>2 per cent of t .&\\ of shell. 



'urst the seam if single riveted; 

 1 20 per cen- ed. 



To determine the ng pressure divide the 



re of the ace by the factor of 



uses a factor of 



.ijle rive: - 20 per cent for double riv- 



eted 871 -r- 6 -- 145 ll>- tlie safe working pressure of 

 Mdilar lx)iler. if ^inple riveted. 



