. Annual report of the American Institute, of the City of New York. Science. Polytechnic Association. 839 <p q -Jsin. <p. 135° 45° 140° 50° 145° 55° 150° 60° 155° 65° 160° 70° 165° 75° 170° 80° 175° 85° 180° The distribution of effective force in this case is shown in the fol- lowing diagram to be even more disadvantageous than in the case preceding; but the work is here principally thrown upon the first quarter revolution, instead of on the second
. Annual report of the American Institute, of the City of New York. Science. Polytechnic Association. 839 <p q -Jsin. <p. 135° 45° 140° 50° 145° 55° 150° 60° 155° 65° 160° 70° 165° 75° 170° 80° 175° 85° 180° The distribution of effective force in this case is shown in the fol- lowing diagram to be even more disadvantageous than in the case preceding; but the work is here principally thrown upon the first quarter revolution, instead of on the second, as in that. 4. We have finally to consider the case of the heavy piston en- gine, werking with short cut-off, and with such weight in the reciprocating parts as is indicat- ed by theory to be that which most equally distributes the work over the circumference described by the crank. The cut-off for which the calculations are made is, as in the case last considered, one-eighth. In computing the coefficients of effective force for this case, it must be borne in mind that the initial steam pressure must be times as great as that which would do the same work without cut-off; and the part of this which, according to what has gone before, it is most advanta- geous to use in overcoming inertia in the reciprocating parts of the engine, is to the total initial pressure, as to , for a one-eighth cut-off. Hence, therefore, the formula for the coefficient will be sin.^—^-— ? The sign connecting the terms is negative; but when <p exceeds 90°, 2<p exceeds 180°, and ^ beoomes essentially negative ; so that, during the second half stroke, the coefficient is the sum and not the difference of the two terms of the formula. The first form of this formula is only to be used for the values of <p in which r v. s. p exceeds Tc. For values less than this, the formula is . 0 sin. — —— . Please note that these images are extra
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