MOTORS & MOTORING

Dominion, Volume 9, Issue 2823, 14 July 1916, Page 9

MOTORS & MOTORING

JJ3r Clutch.] The Differential. Elimination of the differential from the car of the tuture would certainly (says ail authority) make ior cheapness as well as mechanical strength, and simplicity, features ivhich are becoming of mcreiiding importance. In. theory the ono great object of tho differential as applied to. a ear is to equalise the drive on the wheels when taking curves, tho wheels having to rotate at different speeds by reason of tho difference of the circle diameters they have to uiovo in. As tho wheels, however, are only about 4ft. apart, and the majority of turns made in ordinary work are of a largo radius, the difference iu the speeds is actually a small aauount,. and it may be said that 97 per cent, of the driving Leing for ail practical purposes straight ahead, there is not much work .for the.differential to do, even assuming that it does that small amount well, and this is not generally admitted. Now, the penalty for discarding this complicated and expensive piece of mechanism is that the wheels must at times skid on the road and cause extra wear of the tyres. On the face of it, this would soem something to be avoided, but' /practical experience proves that there isactually a lot more tyre-skidding and extra wear" caused' by the differential than is represented by the amount it prevents bv the exerciso of its prima function, tor instance, most car-owners are well aware that now and again when starting off, or driving, effort will all be thrown on to one. wheel, and this will spin round on tho road surface, whilst the other remains fixed, with the result that the car does not move, and the rapidly-revolving wheel is wearing its tyre at ail excessive' rate; in fact, two or three minutes of this wheel-spinning will take more out of tho tyro in the shape of wear of"the .tread than several hundreds of miles of- normal wear and tear will accomplish. In practice, the condition that must necessarily exist fpr tho differential to act properly, vizi, equal adhesion of cach driving wheel, rarely obtains, for, the obvious, reason that road surfaces are imperfect. The skidding that goes on solely because of this is a measurable quantity per mile run, and in a total of several thousaiids of miles, it must add up to a large figure; in fact, in certain tests carried out with a plain solid axle, i.e.,. without tlio differential, a certain set of tyres actually showed a markedly longer life than a similar set did under equal ronditions, but rising tho conventional differential axle. Given tyrea of exactly equal size, and pumped up to tho same pressure, two conditions | that would have to be carefully attended to, there is no particular reason why the differential • need be retained-rit would never be missed. A Motor Toy. A popular toy, the "scooter," is to be motorised by an American firm. Tho European patents. aro not yet completed, so that ono is unable to give inside details of tho mechanism. The child's "ska-cycle,"'or "scooter," is taken as the basal idea,' but is built with a wider platform (12in.) and larger wheels. 'These latter are built "up of pressedsteel discs and shod with larger, rubber tires. The rear wheel is furnished with a mudguard, the broad platform' serving a like purpose for the front wheel, which is the driver, and carries all .the mechanism. This front wheel is driven ■tby a small air-coold motor-cycle engine, the' engine being mounted on one side of the wheel, witlv an outside flywheel on tho other, so .-that the weight is approximately balanced. .The fuel tank is mounted above the wheel in front of the steering post, and tho carburetter is immediately over ■' tho base chamber. Ignition' isf probably by diy Battery, enclosed. with, the,- fuel tank in the case oyer tie wheel. Tho steering post carries two Bowden wire engine controls, mounted, outside, and carried down the front,'and'-hinges, so as to turn down into a 'horizontal .position When not. in use, and for stowage, when the entire machine occupies a space of" only 50in. by 21in. by -12in. Control of the'machine, is. stated, to bo effected by, the'forward and backward action of the steering pillar, the arrangement being' claim-' ed to bo jiuch that ''the natural motions of i the operation provide the simplest possible management of the/machine." :: Apparently you start the engino by pushing the machine along, and, when the engine fires,. stop on .to the platform,; and "there you are," whilst ■the more nearly . upright the steering pillar is- kept theyfaster the' machine goes, and if you lean back and slope the piUar tho speed is checked.. It is claimed to, be equal to a. 21 m.p.h. speed; and to be'able : to climb the steepest hill, ■whilst tho fuel consumption is given at about-120 miles per gallon.

Here and There. Word comes from St. Louis (America) that th 6 local policemen- ;iro using Tim- ■ nbouts "to' round up motorists who so far Virget themselves as to exceed.the.speed limit,-., it having ■ peen found that such are, more, useful than ■ the motor-cycle. Tho records of the ' Court show that these runabouts liave teen of valuable assistance, and the Magistrates have fitted the culprits in fines Tanging from 250 to 500 dollars, which- ]should .just about help to pay handsomely for the upkeep of tho runabouts. . During the Winter months many motorcycles stand idle for.-. the greater part of-.tho-time. •■■lt often happens that: a week or more may elapse between runs. When this occurs there is sometimes a certain amount of difficulty experienced in getting the engine to fire. The shed in which the machine has been kept may be waterproof, but unless a lamp lias been kept burning during tho bad weather, there is always a danger that the dn-mp has entered the house. In all probability- jion-starting is due to the magneto having become a little damp. Ihis can be tested in the. following way lake_ out the sparking plug and lay it on the cylinder. Care must bo taken that tho central electrode does not come m contact with the metal. Wheel the machine' forward, and look out for a spark between the points. If there is " 10 contact breaker and see it the rocker arm which carries one of the platinum, points is working freely. If not, tako off the contact breaker and tho arm. The fibre bush in which it T°,''-if, mar 130 swollen with the damp. A little—a very little of the fibr© should be filed off or rubbed down with emery until the rocker arm works easily. Tho number of motor vehicles registered in the United States on January 1 191(i, wm 2,432,788, of which 71,026 were commercial vehicles. Thero is one car for every 42 people in the United States. Ihe largest ■ registration is New York, namely, 212,844, and tho next largest in Illinois, namely, 182,290. In lowa there is one car for. every 16 persons, and in Illinois one for every 33. Of all the states lowa has the largest number of motor vehicles in proportion to popular tion. It is estimated that .£100,000,000 is spent annually in the States on motoring, equivalent practically to Jjl per head of population. Japan is rapidly building up a foreign trade in motor-cycle tyros. Shipments of such goods . from that country during the cloven months ended in November last attained a value of J2313,500, as compared with tho corresponding period of 1914. Thero aro many cyclists and, motorcyclists who repairs small splits or te«ars in their tubes by tho simple expedient of affixing n patch, as witli nn ordinary puncture. This will serve a short time, but eventually thero will again be trouble, owing to the split having spread until it reached tho etle of tho patch.' Tho liability of a split to enlarge underneath . a patch does not appear to bo generally known, but it is tho cause of many unexpected and inconvenient deflations. The only unfailing remedy, says tho Dunlop Rubber Co., is to cut a small piece of the tube so that an oval holo is left, or a split with a circular hole at each end. If this is done cleanly there is nothing that will sprend, and a patch then applied will effect a permanent repair. No cyclist will object to removing a littlo of his tube, if it will prevent quite a lot of tho tubo rcmov- j ing itself later. Lighting-up time:—To-day, 4.39 p.m.; next Friday, 4.45 p.m.