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356 The driving engines are of the three-cylinder, four-stroke, non-revers- ible, single-acting type, each giving Se 5, b. p. at 450 ©. p.m. With each engine its two-stage compressor is driven direct from the _ crankshaft, while the engine frames are of box- form in two pieces, strengthened in- ternally by columns, and have easily dismountable steel plate doors on each side. The starting, fuel injection and exhaust valves, are placed on the top of 'the cylinder heads. An adjustable governor is fitted, which regulates the lift of the suction valves of the fuel - pump,. thus varying the quantity of oil injected. Below the fuel pump may be seen a _ semi-rotary pump which supplies cooling water for the working cylinders and air compress- ors. Both these auxiliary motors are direct coupled to continuous current THE MARINE REVIEW Siemens-Schuckert dynamos. There is also a belt pulley mounted on the crankshaft from which is driven a countershaft suspended from _ the engine-room beams. From the other end of this countershaft two low- pressure compressors are driven; these compressors are placed forward of and on the same axis as the auxil- iary motors and supply air for the fog siren at a pressure of 2% atm. The direct-driven compressors of the auxil- iary motors provide air at a pressure of 220 lbs. for the purpose of driving the windlass, a duplex general service donkey engine, and the ship's whistle. The various compressed air storage flasks, namely, for starting, fuel-injec- tion, pumping and signalling purposes, are arranged in the port and starboard wings of the engine-room, above the auxiliary sets. The auxiliary compressor is built October, 1913 cylinder and 90 de- There is V-shaped, the driving compressor being set at grees to each other. one single-cylinder Diesel engine of 5 bh. -p, at. 000 Tf. 'p.. m.,and the compressor is of the two-stage type. It supplies air for starting and fuel injection purposes, and to work the general service donkey, and has also a small bilge pump directly coupled. its principal "use, however, 1s 'as a stand-by in the event of the total failure of the air supply, and although constructed to start on low-pressure air, it is large enough to generate sufficient air to start the main 200-h. p, engine in a very short time. The du- plex general service donkey pump is oi 15- gals. per minute capacity and, as already mentioned, is connected so as to pump the oil and_ ballast tanks and bilges, and deck washing and for fire service. . ° -@ * Heavy Oil Engines Decibton of the Nurnierg Two-Cycle Engine as Built by the New Londcn oan & Engine Co. EFORE beginning the descrip- B tion it should be pointed out that the heavy-oil engine is not the simple machine that many writers and exploiters of the engine have made it out to be. The general impres- sion prevails that all that is necessary to do to operate this engine is to turn a wheel, and the operator then can sit down and read a newspaper, the engine taking care of itself. This sort of misinformation has done incalcu- lable damage to the heavy-oil engine industry, and probably has been the cause of the very slow development of the engine in the United States. Lower-power stationary engines do run exceedingly well with very little care, but the higher-speed engine and the marine type require much more care than the slow-running stationary type. As a matter of fact there are as many complications in the Diesel engine as in the steam engine, and if one takes into consideration the rela- tive newness of. the heavy-oil engine, as compared with the steam engine, the complications are much more nu- merous. For instance, in the 450-H. P. engine to bé described there are about 2,500 different kinds of parts. One of the first things an engineer *From the Journal of the Society of Naval ngineers, prejudices. In engine, must do when taking up the heavy- oil engine is to drop his steam-engine sO many ways. the method of operating is so different from the method of operating a steam that to a steam engineer it would appear that nothing but disaster could follow the use of such methods. For instance, the steam-engine cylin- ders are jacketed with steam, while the oil-engine cylinders are jacketed with water; the steam engine requires slow and uniform warming up, while the oil engine is started up without any preliminary preparations. There- fore, when the study of the oil en- gine is taken up, a fresh start should be made, and the subject approached with an open mind, unhampered by steam-engine prejudices. There is too much of a tendency, when trying ort something new and something goes wrong, to say that the new thing is no good, and too little of the opposite tendency, of making the new thing good by correcting its faults. And this is exactly the problem of the heavy-oil engine--to correct minor faults. It should be remembered that even with the great strides made in the last five years the heavy-oil engine jis still an infant, and much remains to be done before it can approach the 'ment of the oil engine is By Lieut. Comdr. Louis Shire degree of development of the steam engine. Much has already been done, and the results shown are remarkable, but a great deal more will be done, for there are many problems yet to be solved. One of the interesting side questions that have arisen is the one of castings. The heavy oil engine is the despair of iron foundry men. So far, in the construction of these en- gines for submarines, 90 per cent of the cylinders cast have been rejected at some time during the process of manufacture. This trouble has been so great that the manufacturers have put an engineer on the work of solving this question. It had to be approached from a scientific standpoint. The questions of gates, risers, chills, cores, etc., were thoroughly studied, and Many experiments made. It is believed that the development has reached the point where 50 per cent of the cylin- ders will pass all the tests and trials. This merely shows how the develop- . affecting branches of engineering, and indicates the way the development is BOs for when the material ques- tion fe solved, most of the heavy-oil engine troubles will be solved. Ma- terial troubles enter into other parts of the engine, as, for instance, valves and packing. These are not so. serious other