MOTORS & MOTORING

Dominion, Volume 9, Issue 2847, 11 August 1916, Page 9

MOTORS & MOTORING

LBi CijUi'OH.l Electrical Change-Speed Cears. According to .tho "Motor," electrical change-speed mechanism is being developed as a commercial possibility by one of the leading English firms. The final decision as to tlie way in whioh the change of speed will actually be made, it remarks, is not yet deoided, but in any case the method will be found to be a great improvement ou present-day principles. For example, it will be possible merely to press a. button on tlie steering-wheel and everything else will be done automatically. The declutching movement could be done electrically, and even the precise moment for making the change, selected with unerring precision by electrical means, and the clutoli then let in again. Alternatively, the declutching coufa be done by the pedal iu the ordinary, way, and the change made electrically. Whatever tho system adopted, it wijl prove a notable advance in tho science of* automobile construction, and the eminence of the firm interested in this new invention is a sufficient guarantee of its practicability. Electrioity is playing, and will play in the future, a larger part in the general field of operations of the up-to-date motor-car, and this new development is one which is probably destined to be an important feature in the post-war evolution of the motorcar. A Motor-Cycle Defect. j Though possessing some features of design which render them superior to ■last. season's models, certain of tho English 1916 motor-oycles, which have been modified in other respeotß, Btill retain, says tlie "Motor Cycle Trader," unsatisfactory silencing arrangements; indeed, in more than one case,the term silencing can only be \ised in a comparative sense, and With very little meaning at that. It always appears strange that one firm should be able to provide satisfactory results,' and another not in such an/important matter as that-of the silencing of the engine, and from tests made it has not always proved that the noiseless engine is the more powerful by any means. The principle of the "free exhaust" is right enough in its way, and we know, of course, that back pressure on the piston is a thing to be avoided as much as possible. There are other and equally weighty considerations, however, to be observed, and experience shows that freedom of escape for the burnt charge can be secured whilst at the same time there is a substantial reduction in the degree of noise created. Retardation of the gases as they pass from the exhaust port to the atmosphere must be devised 0113 system which, baffles but does not seriously impede progress, and by means which break up the force without greatly reducing the velocity of the discharge, -tho action desired, being based in the "extractor" principle, and causing tho gases to be impelled towards the exit and drawn rather than pushed out of the silencer. -It is'a very unpleasant experience to have to drive a noisy motor-oycle for any distance, especially a single cylinder' one. . Tlie sharp detonating sound emitted becomes more and more objectionable as'the ride proceeds, and to some, indeed the majority of riders it has, if anything, a more tiring effect ths,n that' produced by vibration itself. A quiet machine is pleasant to use, aiid if tlie quietnoss ts obtained by the proper methods there need bo no fear whatever of ill consequences where working efficiency Is concerncd. Commencing with the knowledge that an absolutely free ex'haust, such as would be obtained by leaving the silencer off altogether is not only objectionable' on the '■ score of noise, but actually, impairs ..rather than assists the etficiency of tho engine, we can work down by degrees ,to a stage representing the point at which tne best average results are secured. This point may be readied by various methods, and at the same time add, if anything to the development of power. Tills is a. matter which interests the majority of those engaged in the motorcycle industry, and equally those who aa users of motor-cycles feel tho want of some better arrangements than • those already employed in so many cases. Dragging Brakes Reduce Power, Do not expect a brand new car to show tlie speod, power, and flexibility of a car a few months old. In the new machine the parts aTC tightly fitted, and it may require from 300 to 500 miles of operation before the moving parts are properly worked in. A frequent offender is tho braking system, jack' up the rear'wheels and turn them. If little effort is required and no scraping sound is heard the brakes arc'not dragging. If the brakes dragit not only will reduce the speed or the car, but reduce the mileage per gallon. Dragging brakes also generate much. heat, and one can tell by feeling the outside of the bands whether' or not they are excessively hot after a run.\ A new car may show only seven or eight miles per gallon because of the tightness of its parts, yet after it lias been driven 500 miles it may show ten or twelve more, because there is not so much power lost overcoming friction. Here and There. \. In answer to a query bv "Amateur" : You can get results of a kind by painting the car-body with one of the airdrying enamel paints, of' which several are on the market. If you cannot get the paint locally any one of a number of firms in Wellington would recommend a good and suitable brand, and advise you as .to the quantity required. Unless you have had some experience you had better not attempt varnishing. Before applying tho enamel paint, thoroughly clean the work, removing all grease, etc. Then lav on the paint in thin coats, using a clean, but well-worked brush—not a hew one. Two coats should bo enough, but this will depend upon the condition of the body. In this way you should got it fair finish, though, of course, it will mot compare with that obtained by applying and rubbing down a succession of coats of hard elastic paint as a preliminary to varnishing. It is stated that the United States Government Commission appointed to deal with and report on the petroleum trade situation in America has reported in terms generally suggesting that proceedings can bp taken against certain interests under the anti-trust laws. It is anticipated too, that. Congress will strengthen the law with the object, of slopping unwarranted rises in price and mal-practices connected . willi the oil'industry nf America. A resolirceful English motorist has solved the taxation problem by removing two of the four cylinders—ouo of the great .but hitherto unappreciated advantages of separate- cylinders. He admits that ambling along on two cylinders is like walking on one leg, and means a big loss of speed, but lie prefers this to the loss of his cash. A. thirty-two- page booklet dealing wiC?i ali matters pertaining to motorcycle tires has just been issued by the .Dun'ipp Rubber Company. Motor cyclists can obtain a copy for the askling from their agent or direct from the Du/.lop Company. ' Of course, when you Ijoav hissing that conies from escaping compression you naturally think of valve grinding. 'But it does not always follow. A small niece of grit may become fastened to a valve-head surface, and prevent I'.io valve seating tightly, or a variation stem adjustment by_ vibration may cause the valvo to seat imperfectly,'and in either case there will be a hissing sound. Lighting-up tiine.:--To'day, 6.7 p.m. Next Friday, 5.14 p.m.