ENGINEERING. 



No. 66. Goss, W. F. M. High Steam Pressures in Locomotive Service. Octavo, 

 144 pages, 12 plates, 120 text figures. Published 1907. Price $1.25. 



A study based upon experimental investigations concerning the effect of changes 

 in steam pressure upon the efficiency of steam locomotives. A basis for discussion is 

 given in the results of 100 locomotive tests arranged in six series, a definite boiler 

 pressure being assigned to each series. The range of pressure was varied from 120 

 pounds to 240 pounds per square inch. The presentation includes a description of 

 the research and of the means employed in its advancement; a discussion of diffi- 

 culties in operating a locomotive under very high steam pressures; a statement of 

 facts concerning boiler and engine performance under different pressures, concern- 

 ing machine friction, and concerning the degree of efficiency attending the perform- 

 ance of work at the draw-bar; and a concluding discussion with reference to the 

 more general question of boiler pressure versus boiler capacity as a factor in eco- 

 nomic operation. Four appendices present respectively a description of the locomo- 

 tive experimented upon, methods and data derived from tests, general data concern- 

 ing the weight of boilers, and a file of typical indicator-cards. 



No. 127. Goss, W. F. M. Superheated Steam in Locomotive Service. Octavo, 

 v-f-144 pages, 6 plates, 88 text figures. Published 1910. Price $1.25. 



A study based upon recent foreign practice and upon experimental investiga- 

 tions concerning the use of superheated steam in locomotive service. In the course 

 of this study generous attention has been given German superheating locomotives. 

 These have been inspected when in the process of manufacture, when in service 

 upon the road, when in shops for general repairs, and when in roundhouses for 

 routine attention. Observations thus made prove that superheated steam may be 

 successfully used in locomotive service without involving mechanism which is 

 unduly complicated or difficult to maintain. The experimental investigations were 

 conducted at the laboratory of Purdue University. They included forty-seven 

 formal tests of an American-built locomotive. The boiler pressures employed dur- 

 ing these tests ranged from 120 pounds to 240 pounds. The results show the re- 

 lation between the degree of superheat developed and the output of power, together 

 with such other significant data as water and fuel consumption. Heat balances 

 covering the performance of the boiler and superheater are given for eighteen 

 tests. The results are compared with those which are presented by Publication No. 

 66, entitled "High Steam Pressures in Locomotive Service," for the purpose of 

 showing the effect of superheated steam upon the power and economy of the 

 locomotive. Many results are presented graphically. Four appendices present a 

 description of tests, methods, data, etc. 



No. 79. DURAND, W. F. Researches on the Performance of the Screw Propeller. 

 Octavo, 61 pages, 85 text figures. Published 1907. Price $0.75. 



An investigation into the influence on screw-propeller performance of the three 

 chief factors: (1) pitch ratio, (2) slip ratio, (3) area ratio. Forty-two model pro- 

 pellers of 12-inch diameter were employed covering variation in pitch ratio from 

 '0.9 to 2.1 and in area ratio from 0.18 to 0.72, each propeller being tested through a 

 xange of slip from 10 per cent to 40 per cent. Measurements were made permitting 

 'the determination for these model propellers of thrust, work absorbed, and effi- 

 ciency. The reduced results are shown in various forms, tabular and graphical, and 

 their application to problems of propeller design is discussed. Similar results are 

 also given for some 47 combinations of two propellers on one shaft, comprising 

 various arrangements of the above propellers as to relative pitch ratio, distance 

 apart, and aspect of blades. 



34 



