MOTORS AND MOTORING

Dominion, Volume 11, Issue 157, 22 March 1918, Page 9

MOTORS AND MOTORING

Hit Cluioh.l

Tyro Inflation, . Some observations on the important question of tyro inflation were issued by tho Dunlop Rubber Company. Thn ntlvico tendered differs so much, it is observed, that inexperienced motorists hardly know what to do—run on fairly slack'covers or on well-inflated tyres. The first-mentioned practice, according to tho. Dunlop experts, is calculated to do a great deal of harm. Tho pneumatic tyro is designed io take its resiliency from the air contained within, and not. from the rubber used in its construction. If there is insufficient air compressed inside tho cover to provido an adequate cushion or support for tho walls of cover then the casing suffcr.s accordingly. Covers are designed to bend about one-twelfth of their cross sectional diameter. In fl,ii;toning out even this much considcrahlo heat is generated between tho various plies of fabric, but tyres are so desifjned that they can stand this destructive internal heat for a good long time, provided the flexing does not become more ■exaggerated. The balance of a pro-perly-con strnctcd tyre is such that the tread will be worn through about the time the casing is. ready to give out from constant .flexing. But if the lyre is run wjth considerably less.air pressure than it was designed to carry, the flexing is going to be .very much increased, the strain on. the plies of fabric will be greater, arid the casing will break down long before the rest of the tyre its. worn out. This, of course, means a considerable economic loss, which is. undesirable at any time, hue which is particularly undesirable at present. The only.real way to determine tyre pressure is by uso of an accurate gauge. The proper pressure, of course, varies with the weight, of the cjiy and load carried, and can uo determined in any given case from a carefully-worked-out scalo published by loading tyre' companies.. This, pressure should bo maintained within a ten-pound limit .at) all times, and the tyres tested .and reinflated at least once a week. By being careful on tin's one point alone it is possible to increase the tyre mileage from ten to fifty per cent. v Metal Wheels. Up to the present, 'American makers' have remained aloof from tlio metal wheel development. This is ex.plained, says an exchange, by the fact that the United States had a vsry good supply of second-growth hickory, nnd that wood wheels iriade in that country have been of better quality than wood wheels made in Europe. Now, however, there is a shortage of second-growth hickory, with the consequence that wheals now being made are inferior to those of a few years ago. Further, the American military authorities have been impressed by tho excellent results obtained by all types of metal wheels in Europe, and are disposed to insist on similar typos for their Army vehicles. America may bo a little longer than Europe in changing her wheel construction, but there- is no doubt she will change it. For colonial service the rnotal wheel has such wonderful advantages over the wood variety that it is surprising American manufacturers have not considered the change long ago.

A Door-Opening Device. An electrical contrivance which cnablcs the motorist to unlock his garage floor and run in the car without alighting lms boon patented, in America. According to particulars' published, the garago door can be opened 'by pressing a button which turns ion the lights in ! tho ..building, unlocks the door,' and ; folds them back clear of the opening, all within a few seconds' time. : The j push buttons are arranged on a metal j post outside in a convenient place at ! the side of the drivoway where tbo ,j driver can roach out with one hand i and operate the device. ) One push ; button opons up the garage, another ! closes it, while a third stops tTie doora j instantly. Provision has been mado j through a spring-checking devico to I prevent accidents to persons or' machines, should they, by oversight, be standing in the opening after the clos-ihg-bntton has been pressed. The Engine Brake. ' Writing'of the safety and control of I motors, an English driver deplores the i abandonment of the engine brake. At one time, ho states, it had considerable vogue. The Rover car was one so fitted, and the brake was of such power that any steep hill could safe- ] ly be descended without using the or- ] diriary brakes.' The system was found I to be very effective" with tho Saurer heavy lorries, -which are used on the mountainous' Toads of Switzerland. Touring- cars were, also-so' oqiiipjoed. Tho control of the .bi'ake was. effected from the stecring-wheclj the throttle lover when pushed beyond the closed position acting on the camshaft. Thus, with one hand,, the driver could vary the speed to any extent by. regulating the amount of gas admitted to the cngina, and by continuing tho movemont of the'lover could apply the brake.

Hereand There, .' .. . : As all motorists know the variation in I#ie quality of petrol is' yery great. It is evident that the British' Army has experienced the same thing, particularly in regard to the effect of such varied quality on the efficiency of aeroplane ougines, which, working under such. very exceptional altjtudo conditions,, and requiring.- .such/very exceptional efficiency, may be seriously affected in their .work by poor fuel. It reported from Washington that representatives of Franco, Italy, Great Britain, and! the '.United..States have ■itjrord on a. plan to "design" a new braiid of fuel, i'or aeroplauo use, which is to he taken as a world standard for this'purposa. It is stated that this particular grade of'fuel does. not at presont exist, hut tho engineering scientist's concerned aro being put to the work" of '"designing" it. .At pre'bcnt tho Allies are using .no fewer than ten different grades of fuel for aeroplanei work. According to the specifications laid down,. it is claimed that tho new fuel will be more efficient thiiu that used in motor-earn In-day. Tho results of the experiments should be interesting to motorists. It has been computed -that 77 per cent, of the world's motor-cars aro to be found within tho borders tho United States of Aniorica. Kvery fifth family in that country now owns its motor-car, and five per cent, of the population is. now dependent on the. automobile for its living. Lighting-up time:—To-day, 0.2 p.m. Next Vridaj, 5.50 p.m.