. American engineer and railroad journal . Fg- 3- Fig. 3 is a spoon-shaped propeller built both with two blades(as shown in tlie drawing) and also with four. The shape isclearly indicated in the sketch, also the reinforced edges. With two blades it weighs .70 kilogram (11 lbs.). The area of two blades = .085 square metre (.915 sq.^ft.). The outside diameter = .816 metre ( in.). The radius of gyration = .275 metre ( in.). 242 THE AMERICAN ENGINEER [May, Fig. 4. Fig. 4.—Phis drawing represents a shovel-shaped hollowwarped surface, tapering to a point, with constantly increas-ing
. American engineer and railroad journal . Fg- 3- Fig. 3 is a spoon-shaped propeller built both with two blades(as shown in tlie drawing) and also with four. The shape isclearly indicated in the sketch, also the reinforced edges. With two blades it weighs .70 kilogram (11 lbs.). The area of two blades = .085 square metre (.915 sq.^ft.). The outside diameter = .816 metre ( in.). The radius of gyration = .275 metre ( in.). 242 THE AMERICAN ENGINEER [May, Fig. 4. Fig. 4.—Phis drawing represents a shovel-shaped hollowwarped surface, tapering to a point, with constantly increas-ing curvature. Itsextemaldi- 1 ameter = - , metres (40 in.). Its totalweight = .97 kil-ogram (2* lbs.). The area of theblades = .1223square metre( sq. ft.). The radius ofgyration = .2997metre ( in.). Fig. 5 is anS - s h a p e d fanwheel, veryslightly con-cave. The area ofthe blades =.3322 square me-tre ( sq. ft.). The radius ofgyration = .215metre, ( in.). Finally, tig. 6shows a screwconformingclosely to a truehelicoidal sur-face of constantpitch. The cen-tral part is builtup of two thick-nesses of tinnedplate, with stiff-ening angle of theblades variesfrom 9° to 45°, as shown by the cross sections. The external diameter = .980 metre ( in.). The total area of the blades = .089 square metre (.958 sq. ft.). The radius of gyration = .3168 metre ( in.). The two methods used for measuring the thrust Aare shownin figs. 7 a
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
