are a single bronze casting, motion being obtained from the low pressure engine through the medium of light steel levers and links. The thrust bearing is arranged on the after end of the engine bed, where it is under the immediate supervision of the engineer. The space occupied by these engines fore-and-aft is one-third less than is required for the ordinary style of construction, while the entire engine can be oiled and inspected from the starting platform. On a recent trial of one of the small sizes of these engines some remarkable results were obtained. The diameters of the cylinders were 5, 8 and 13 inches respectively, with a common stroke of 8 inches. With a boiler pressure of 200 pounds, the number of revolutions made was 400, which is equal to a piston speed of 533 feet. Calculated percentage of admission, small cylinder 70, intermediate cylinder 60, large cylinder 70. Horse power estimated 38, 39% and 40%, respectively, or 118 horse power altogether. The entire weight of engine including air and two feed pumps is 2,480 pounds. The propeller was 38 inch diameter by 6 feet pitch, and the speed attained was over 17 miles per hour, The vacuum maintained was 26 inches, which is very remarkable considering the high number of revolutions, while the engines were absolutely noiseless and developed no tendency to heat or cause trouble in any way. On the score of economy these engines make a most satisfactory showing, furnishing a horse power for 1.61 pounds coal per hour, which is equivalent to less than one ton of coal for ten hours steaming, or a distance run of about 190 miles. The reputation gained by Mr. Sullivan in the manufacture of light yacht engines is an enviable one. Fig. 81 shows a triple-expansion engine for steam yachts, by Messrs. Riley and Cowley of New York, who have met with great success with these engines. They have fitted them on board a large number of fine yachts, to the great satisfaction of all concerned. It will be noticed that this engine presents a very open front, enabling attendant to adjust and inspect working parts at all times with facility, and allowing of repairs to be made without pulling engine apart. One of the marked features of these engines is the entire absence of vibration, even at highest speeds. This is due to the care with which the reciprocating parts are balanced. The ports and passages are so proportioned that excessive speeds are possible without undue frictional resistance to steam in passing through them. The engine being free from pumps, delivers its full power to the propeller, while the pumps being independent, may be adjusted to their work. It is self-contained, and of exceeding light weight. |