Great Falls High School - Roundup Yearbook (Great Falls, MT)

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8 THEROUWDUP Gas or gasoline vapor will not explode unless mixed with a cer- tain amount of oxygen. The device that does this work is called the carbureter. It consists of two separate chambers made of brass, or glass ; a float chamber, in which the flow of gasoline from the supply tank, is governed by a cock or hollow brass float, which operates a needle valve; a vaporizing chamber, where the gasoline is mixed with the required amount of oxygen. A feed pipe runs from the carbureter to the ignition chamber, through which the vapor is drawn. The charge of gasoline and air being in the cylinder, it must be ignited at the right instant, so we can get a full amount of power from the explosion. The two most common igniting systems are the induction coil and high tension magneto. The coil consists of a coil, contact breaker, primary and secondary winding mounted on the dashboard. The battery used may be either dry or storage, and is usually carried on the step of the machine. The coil changes the low battery E. M. F. to an E. M. F. high enough to jump a small air gap inide of the cylinder. The spark plug is a small gap built in porcelain or mica and fitted to screw in the opening meant for it in the cylinder head. One side of the secondary is connected to the iron work of the engine and the other side is connected to the spark plug. Now when the chauffeur cranks or starts his engine, he turns the main shaft with a crank, the main shaft turns the two-to-one by gearing mentioned before, the cam on the two-to-one shaft opens the mtake valve and when the piston goes down a charge is pulled into the cylinder. Now when the piston comes up, it compresses the mixture, the spark occurs and the mixture, rich in gasoline, explodes, driving down the piston. The Kinetic energy of the fly-wheel on the main shaft keeps the wheels turning until the next explosion. The timer is a little device, controlled by a small handle at the driver ' s seat. The timer is run by the two-to-one shaft also, and in it the contacts are so arranged that the spark takes place just as the piston starts down after the compression stroke. By turning the small handle at the wheel the time of the spark is advanced or re- tarded and the engine runs faster or slower as desired. The clutch is the device by which the engine shaft may be con- nected or disconnected from the driving shaft. This is usually oper- ated by a foot pedal. The clutches in use today are the cone, mul- tii)le dice, and friction. Some form of transmission is necessary in order to change the speed of the auto, so that we can climb hills and then again have it geared high so as to speed up on the level. Between the clutch and back axle is located the tranmission. A handle at the driver ' s seat enables him to slide certain gears on one shaft to mesh with certain ones on another, so the different speeds are picked out. If the ma- chine is shaft driven, this shaft after leaving the transmission gear case, runs to the back axle and terminates in a bevel gear, inside the differential.

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THIRD YEAR JUNE, 1910 NUMBER FOUR The Motor Car DespilL the large number of aulomobiles in use today, there are many boys and g ' irls who don ' t know where and how the power is developed that sends the machine along; and how it is connected or transmitted to the (h ' iving wheels. There are steam and electric cars, but the gasoline engine is the most common source of power for the self-propelled vehicle. Ihe engine is mounted just l)acA of the front axle. It may have one, two, four, six or more cylinders, casted separatel} ' , in pairs or all together. A cylinder is made of cast steel, say five inches in diameter and seven inches long, closed at one end. All six cylinders of a six-cylinder en- gine work the same as one, so the latter will be descrd ed here. The cylinder has four openings. The intake part, where the ex- plosive mixture is let into the cylinder; the exhaust part, where the burned gases go out ; one for the spark plug and one for a small pet cock, used to put gasoline or lubricating oil into the cylinder. This valve is sometimes opened when starting so as to make it easy to turn the crank. The piston is an iron plunger that fits snugly in the cylinder. The piston rod connects the piston with the crank on the main shaft. The main shaft, with cranks, is enclosed by a casing of alumnium or iron. By a set of gears run l y the engine itself there is a smaller shaft made to revolve once while the main shaft, to which is attached the fly-wheel, makes the revolutions. On this two-to-one shaft, as it is called, are mounted two small solid wheels about an inch and a half in diameter, having a large bump on the circumference, called cains. Running on these cams are two other small uniform solid wheels, whose axles are connected to the valve stems, which are rods of iron about five-eighths of an inch in diameter. Fastened on the upper ends of these valve stems or rods are the valves, which close or open the intake and exhaust openings of the cylinder at the right instant. When the cams on this two-to-one come around to a certain posi- tion, they push open the valve, thus allowing the new mixture to be taken in or the old gase to be pushed otit, depending on which valve It is. These valves are opened once every two revolutions of the ma n shaft but not at the same time. The intake valve is opened when the piston starts down after the exhaust stroke and closes when it starts up. The exhaust valve is opened when the piston is about half through the power stroke, and closes when the piston starts on the intake stroke.

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THEROU.NDUP 9 The back axle is in two parts and the gears in the differential are so arranged as to allow the machine to turn corners where one wheel moves faster than the other. On account of the heat made by the exploding gasoline vapor the cylinder must be cooled or it will become so hot that the charges ignite at the v ' rong time. ater cooling is made possible by casting a jacket all around the cylinder and water is kept circulating through it either by heat or a pump. Some engines are air cooled and the flanges casted on the sides of the cylinder allow more sur- face to be exposed to the air, thus keeping it cool. ARTHUR lOON, 1910. Fare thee well, dear Great Falls Fligh School, Four short years were spent with thee ; And our paths will soon be severed, But our hearts will loyal be. We look with pride and fond affection On the dear old White and lUue, And to teachers now, and schoolmasters, The Nineteen Tens must say Adieu. E FRANCES KIRWIX, ' -1910.