Publisher's Synopsis
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 edition. Excerpt: ...for the construction of the diagrams to represent a ship's ventilator. When the diameter of base, or pipe to which it is to be connected, is the known quantity, the formula which follows has been used to some extent: Formula For A Ship's Ventilator With A Round Mouth. Diameter of base X 2 = diameter of mouth. Diameter of base X l/2 = radius of back. Diameter of base X yA = radius of throat. Angle of mouth to the horizontal 80 degrees. The form of all pieces to be round at each end, and of diameters equal to the lengths of miter lines shown in the resulting elevation. This formula has been worked out in Fig. 64 to the scale appended, presuming the base to have a diameter of 16 inches, and the fitting to be made in six pieces. It will be noted that the back and throat have been divided into the same number of parts, i.e., into as many parts as the fitting is to have pieces. Lines drawn between these points of division represent the miter lines. As has been previously explained, each miter line may now be looked upon as the edge elevation of a circle whose diameter is equal to the length of the line. There must be as many patterns as pieces in the ventilator, although one-half of each piece may be duplicated for the other half. To Reduce The Problem To Its Simplest Form. The most desirable course to pursue in examples of this class is to construct separate elevations of each piece, with one end parallel to the intersecting line (/ L) as shown at Fig. 65. The elevation in Fig. 65, as will be noted, is an elevation of that portion of the object marked A in Fig. 64, it having been revolved in such a manner as to place the line a b of Fig. 64 parallel to the intersecting line. To transfer that diagram is but a simple matter if we draw, or...
