. American engineer and railroad journal . ect solution), it is high timeto settle this question and to proclaim which one of the solu-tions is correct. I attempted in the last issue (January, 1894) to give a purelygeometrical solution, employing the usual methods of thecinematical geometry ; this demonstration is correct, but Imust confess that the conclusion I made then was wrong : inother words, it is true enough that if the connecting-rod A Bis produced until it meets at C the vertical line drawn throughthe center 0, the speed of the piston is at any time proportionalto the length 0 C, so
. American engineer and railroad journal . ect solution), it is high timeto settle this question and to proclaim which one of the solu-tions is correct. I attempted in the last issue (January, 1894) to give a purelygeometrical solution, employing the usual methods of thecinematical geometry ; this demonstration is correct, but Imust confess that the conclusion I made then was wrong : inother words, it is true enough that if the connecting-rod A Bis produced until it meets at C the vertical line drawn throughthe center 0, the speed of the piston is at any time proportionalto the length 0 C, so that the maximum speed of the piston isattained when 0 0 is maximum. But I was not right in say-ing that 0 C is evidently maximum when the connecting-rodis at right angle with the crank-pin radius, and I want tocorrect this part of the solution. As the correct part of my last demonstration was purelygeometrical, I propose to use only geometrical reasonments allthe way through—that is, to find geometrically when themaximum of 0 C I have shown already that during an element of time, d t,the connecting-rod rotates around the virtual center S. KGis the position of C after the time d t, and if we trace a circlepassing through G, taking 5 as a center, this circle cuts theconnecting-rod A C at a certain point D, and D is the placewhere G was before the element of time d t had elapsed. Reciprocally, if we knew the position of D we could obtainthe next position of C by tracing a circle through D (5 beingthe center) and taking its intersection with the vertical line0 C. Now, when the angle S C A is less than 90° (as shown 56 THE AMERICAN ENGINEER . [February, 1894. in the figure), the point G, thus obtained, will be above C;and whin the angle 8 CA is more than 90°, the point G thusobtained will be below C. But the maximum of 0 C will be attained when the nextposition of C will be neither above nor below C (the maximumcorresponding to a stationary position of G during the tim
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
