THE MOTOR WORLD

New Zealand Times, Volume XLIV, Issue 10210, 21 February 1919, Page 7

THE MOTOR WORLD

SIDE-GAR DESIGN ■:-.7'i;r:i::s capable of further IMPROVEMENT. ;■. '■• ■.-•!--iiv; motor cyelo side-en*, design, i-'-'! iiavinß an eye to tbo future enormously increased demand for motorcycle combinations, it is as well to remember that, although the side-car has been very materially improved, there remain one or two features which still require further attention on the part of designers and builders. One ot them is the sprinßiiiff and another the means of connecting the car to the cycle- iho first of these is. with tew be no means as satisfactory as it should tit and onorV should bo made to remove this stisma from an othen„o giwty bettered style of vehicle llio spn ukine system of motor-cycle and the suleea? should be such that not only the main road shocks ere damped out, but the irntotina vibration set up when rtrifcS dialler surface irregularity nnd " corrugations as well. .*■"■*"■ •'"' wwrds the coupling, it would be an improvement if nil loose brackets .or iunlwwe dispensed with and nothing but brazed ioints used. Such loose fittWs mWit possible to "adjust" the Relative positions of the machine and side-car. but such possihihty ot ad justment is best done without If the sHkcar chassis is stout enoUKh t°. con. tinued strain and the cycle, be set tralv vertical in the first, instance no need should arise for subsequent tarnnerincs with, the connections, and the Fenlency for faddists to sot the motorcycle at this or that nnjtlo, leaning towards or from the side-car, would be Swd 'impossible and one potent source of dancer "moved. Another point is that which refer*, to the tmsatisfactorv behaviour ofside-jMr combinations when driven l^ l *-,... 1 ' 1 ? wheel has a decided tendency to "ft at corners and careless driving at speed is likelv to result in severe damage to rider and machine It "Usually believed that the only way to overcome this is that of. ««««»* the weipht to be carried directly b> the wheel It is difficult to see how this could be done without introdncuuj unprofitable" load, but it should ho posSto minimise the, evil by superior desijm of the chassis as a whole. Attempts were made to improve tyre wear and incidentally- improve the tracking of side-car wheels, some years ago, the Wheel in one case beinir connected to ■the front'wheel of the cycle so that both steered together, whilst m another desisrn the side-car . connections were flexible ■instead of ricrid thus lenvvns the motor-cvcle to be balanced by its rider as when ridinsr solo. USING THE! SPARK CONTROL. A thorough understandings of the operation of a gas enprine is essential t<. !fhe proper handling of the spark r-on-'trol and 19 something that every motor- ' driver' should acquire. If the spark 1? retarded just sufficiently when the engine shows signs of labouring on a lull, 11 will relieve the strain on the enjrine and increase its power at slow spwd. When accelaratine; the speed of tho car U<e engine will pick up moro rapidly and with less tendency, to knock if tho spart is slightly retarded. The spark should be so adjusted that it can only be advanced to Its farthest point when the encino is running at very high speed without much load on it, as for instance, when running fast on a smooth, level stretch of road. Study.out the function'inst of the spark in relation to tho various conditions under which the engine operates and a more intelligent idea of its usage will be gained. RUBBER -SUBSTITUTES FAIL. The war has proved conclusively ope thine—that motor-car tires can he made of nothing but rubber. Incalculable efforts have been made to find a satisfactory and cheaper substitute for rubber, but nothing approaching success has been accomplished. Steel.wood fibre and cotton, each in its turn, have been experimented with, but to no result. Steel tires are durable enough, but thej- fail in all three essentials.-- They fail to give traction, thev transmit vibration to lho car mechanism and they do not cushion the load. Even with air used as a cushion beneath a steel tire, results were unsatisfactory. This construction proved resilient at slow speeds, but at high speeds the inertia of the rim prevented the tire from acting quickly enough to absorb the road shocks and it also failed to give traction. Wood blocks and wood fibre were retired after they failed to display resilience, much less durability of steel. Cotton fabric, likewise, bowed to rubber after a trial.. Tho cotton fabric was highly compressed and applied. It was farily resilient, but lackod tractive grip and "hence was useless on a vehicle which' propels itself by power delivered at the rims of its wheels. Rubber, consequently, continues imperial.