MOTOR NOTES.

Southland Times, Issue 16891, 16 November 1911, Page 9

MOTOR NOTES.

BOW AN AUTOMOBILE WOBKS. No. 11. ■ In the description of the engine, published last week, reference was made to the carburetter, which is the contrivance "Which feeds the petrol to the engine, and In which the turning of the spirit into a gas commences. There arc two coni-, partments in the carburetter, i.e., the float chamber anil the barrel containing the jet. The float chamber is simply a email reservoir holding about 2 to 1 oz. of petrol, and is fed from the main lank. Inside the chamber is the float, which supports two small rocker arms, little bars about half to three-quarters of an Inch In length. Working on a pin. the ends of the arms fit loosely into a collar on the needle valve, which is simply a thin rod of steel, the bevelled end of which fits vertically into a socket just above the entrance of tiio petrol pipe. The float, which is made of spun copper, Is a cylindrical, air tight vessel, with a tube through Its centre, through which the needle valve passes. This controls the supply of petrol to the carburetter, for, as soon as the float chamber tills, the float rises, pushes up the rocker arms, which in turn lowers the needle valve into its socket, and shuts off the petrol from the tank. Thus, the float is continu lly rising and falling, shutting Off or admitting the spirit as it is used, always keeping an even supply. This is necessary, for passing from the float Chamber is a channel which leads to the jet. and the level of the spirit should always be about l-32nd of an inch below the top of it. It is through the- jet that the engine draws its supply of fuel. The orifice is very small, and on a small car a pin could not pass down it. Around the jet is the choke tube, merely a bell shaped piece of spun copper, through which the air Is drawn every time the engine makes its suction stroke, the air, rushing past the jet, sucks out a thin spray of petrol and, being highly volatile, it turns into gas. The choke tube only admits portion of the air required, for petrol vapor requires a large proportion of air to make it explosive. The oxygen in the atmosphere Is necessary to secure complete combustion. There Is what is termed an auxiliaryvalve, which opens and admits more or less air, according to the speed of the engine, because the faster the speed the greater the suction, and the more petrol Is drawn through the jet, requiring a greater proportion of air. Incorporated In the carburetter Is also the throttle valve, which Is operated by the driver or a governor, and bv opening or shutting it the suction is increased or diminished, and the amount of gass drawn In is so controlled and t: e engine made to run slower or faster. There are various designs Of carburetters, but all, with one exception, work on the principle above described. The exception is a wick carburetter, the petrol passing out of the reservoir by capillary action up cotton wicks, past which the air is drawn and Impregnated with the petrol gas. The jet carburetter Is a comparatively small contrivance and will be found usually alongside the engine on the side opposite the exhaust pipes. The term, “gravity,” or "pressure feed” means. In the former, that the supply reaches the carburetter by gravity, the petrol tank being either on the dash board'; or under the driver’s seat. In pressure feed system the tank Is at the rear of the car, below- the level of the carburetter, and air is pumped into the tank to lift the petrol to the carburetter. The initial pressure is gotten by a hand pump, and after the engine starts part of the exhaust is directed to the tank, and a pressure is maintained during the run. To avoid danger of fire the exhaust to the petrol tank passes through a filter or screen. A very low pressure is required to lift the petrol to the level of the carburetter. The next important feature is the ignition of the gas, which will be dealt with In the next article.

At Cardiff recently one of the greatest combinations of applied modern science ever wi nessed was demonstrated by Mr H. Grindell-Mathews, the inventor of a new system of wireless telephony, in conjunction with Air B. C. Hacks, of Cardiff, the well-known pilot of Blackburn monoplanes. Ascending with one of the Mathews receivers on his machine to a height of 700 feet, Mr Hucks easily succeeded in hearing Mr Mathews’s message, which was given in ordinary conversational tone, although a strong breeze was blowing abeam, and he was travelling at the rate of 50 miles an hour. Here we have a combination which at a bound has trebled at least the military value of the aeroplane, us Its apparatus is small and portable, Us message is direct, needs no skilled interpretation, affords little or no possibility of mistake, and needs no aerial trailing screen. Actually, it has gone further already than wireless telegraphy in this connection, and promises no limit of distance. Kecently Mr Mathews succeeded in aeroplaning from the “Western Mail' offices, in Cardiff, to Chepstow. 25 miles distant, and is just as confident of communicating with equal success 60 miles in. any direction. His confidence seems fully justified by the result of one test, when locked in a strong room, walled by 9-lnch of firebrick, and several feet of concrete, he not only made his voice perfectly audible to the experts in the adjoining room, but they could even hear the ticking of his watch. The Grindell-Mathews system it appears la based on the use of a high frequency continuous current, instead of the slower intermittent one, used in Marconi “wireless,” and it is claimed that the former type of current, which is also the basic feature of the new “wireless” system, enables all the peculiar intonations of the individual voice to bo audible at a considerable distance from the speaker. Thus those two terrors, the wrong number and the telephone girl, seem likely to bo abolished, for there is no number in aerophony and no girl.

Owing to the peculiar conditions existing in Afghanistan the automobile presently is to enjoy the distinction of becoming the sole means of modern transportation in use there. After years of semi-barbarism the Amir has become a motorist. Consequently as the indulgence of the pastime requires good roads the decree lias gone forth that good roads shall be built forthwith, while to give permanent impetus to the movement a motor vehicle service is to bo introduced over a 200-mile route across the northwestern frontier. For lids purpose it Is said that the Amir has placed an order for roiling stock to the tunc of over five lakhs of rupees, and upwards, with P. Stewart, of the I’.ombay Motor Co.. Bombay, The impending revolution In transportation is the direct outcome of a piece of subtlety on the part of the Government of India in presenting a fine car to the Amir when he_ last visited India. Before the time of ids return the Amir was so enthused with motoring that he decided not to ulMiidon his new possession, but to provide mean.s for its successful use at homo, ilencc the projected highway improvement, which lias caused the potentate no particular mental or financial strain, since It was necessary merely to order the construction of the roads radiating from his capital at Kabul by forced labour. The new motor lino will run from Peshawar, which is a British territory, to Kabul. Its route lies through the celebrated Khybcr Pans, iif the Pamir plateau, the highest mountainous region in the world.

There are very few people who are able to build an automobile highway, 22 miles in extent, all of winch lies within the 'bounds of their own estate, and George IV. Vanderbilt is one of these few. He has Just finished the construction of a highway, 22 miles long, which leads from Biltmoro House to his hunting lodge on the summit of Mount Pisgaln Xorth Carolina. 2000 feet above ♦ he'cou'ntry house. The road was blasted into tremendous cliffs, and has several sharp turns on the edge of sheer tiro's. which are extremely difficult to ■ith a high powered car of el'base. -MI but two miles of > within Mr Vanderbilt’s and ano tli or 20,0 00 , ■ n constructing a ut-off. o -M the entire road y . i be on his domain.