THE MOTOR WORLD.

Otago Daily Times, Issue 19584, 14 September 1925, Page 4

THE MOTOR WORLD.

Sy ACCELERATOR.

Motorists desiring Information with regard to mechanical or other car trouble*, or on any matter coming within the soone of the eport, pastime, or business of motoring arq invited to send inquiries to Accelerator.” Special efforts will bo made to give the most reliable advioo on »ff topics of Interest. ACKNOWLEDGMENTS. The Big Tree Bulletin and Calendar for August, both of which are artistic and useful to motorists. RELIABLE CHAINS. All-chain drive has become so well established that there was not a single exception to the rule in the recant T.T. races, and chains stood up to the fearful strains of violent acceleration and deceleration in a most remarkable manner. There was only one retirement in the races, officially stated to be due to chain failure, and even in this case there seems there is some doubt as to whether the chain itself or a temporary gearbox lock was the primary cause of the trouble. MEETING COLONIAL NEEDS. The development of British cars for overseas use has been the subject of recent correspondence in English motor periodicals. In many cases the writers urge British manufacturers to make a determined effort to meet colonial requirements in the matter of adequate power and ground clearance. It may be pointed out that the English correspondents who arc so critical of the products of their home factories are taking the complaint more seriously than colonial motorists. There are numerous F/nglish cars available locally that meet every requirement. The inexperienced driver may criticise their top gear performance, but their durability is beyond dispute. Certainly there is room for a still greater range of British cars for tho Dominion market, and no doubt certain of them cannot become eligible unless improved in power and clearance. MORE RECORDS. A remarkable speed was recently attained on Brooklands track, England, on the occasion of a sporting match for £SOO a-side between two of England’s greatest competitive drivers. The contestants were J. G. Thomas (7266 c.c. Loyland) and It. A. .Adridge (21714 c.c. Fiat), the distance being three laps-S* miles. Tlie pace was terrific from tho start, tho monster Fiat lumping away with the lead. Both were driving high up the banking. After a hairraising speed exhibition Thomas won >v 200 vards, finishing at a speed of over 130 m.n.h. The Loyland. which was shod with Dunlop tvres, covered its fastest jap at 129 1-5 m.p.h. The Fiat's best was 1251 m.n.h. Thomas subsequently established new figures for the worlds hour recor , the new mileage being HO miles 1221 yards. The previous best was Ihomass own record, ho having in 1624 covered 109 miles 160 yards in 60 minutes. frame design. Judging from tho design of machines which wore entered m this years X.l. races, English designers have realised tnat a. low centre of gravity and a sufficient degree of rigidity are essential It is dil - cult to judge road holding qualities with out personal experience, but conclusions drawn from the reports of the live races gives a high place to Dougins and Now Imperial machines. An import Ant development was that Webb, Druid, and A.JA forks had auxiliary side staysfitted for the sidecar race, so as to stiffen them laterally. In itself the idea is admirable but like so many innovations this might cause trouble unless frames are strengthened in proportion. If the forks are really stronger than tho frame then twisting strains would be concentrated on the frame and tho head instead pi the “give” being divided between the forks and the frame. ROAD CONSTRUCTION. Auckland can boast of a very creditable and rapidly-increasing mileage of concrete roads. America has 32,000 miles of concrete roads, and continues to add to tho total. Conti over ay exists in England as to tic merits of concrete and bitumen surfaces. There are little more than 300 miles of unsurfaoed concrete roads in Britain. The practice of covering the concrete roads with a bituminous carpet is meeting with the general disfavour of motorists. The advocates of surfacing contend that the bitumen prevents wear on the concrete. Motorists find that tar-sprayed roads are conducive to skidding. It has been demonstrated that the concrete surface affords a better grip. In wet weather bitumen presents an exceedingly slippery surface, and under drv conditions it quickly becomes polished bv the passing of thousands of rubber-shod wheels. Experts have estimated the surface life of a modern concrete road at from 15 to 20 years. There is no doubt that the periodical use of liitumen would prolong this, but there would he an inevitable increase of tho accident hazard. , BOARD TRACK SPEED. A well-known American rider who was recently in Australia has the following to say about board race-tracks: As this type of track is almost unknown in Australia, a brief description of them should bo of interest to Australian speed fans. There are only two types of race tracks used in U.S.A. —board and earthen tracks. The earthen track is rarely over half a mile in circumference, while board tracks are generally one and a-quarter. The speeds attained on the boards are simply amazing, yet they are considered to be the safest of any. The tracks are built on staging and 2m timber laid lengthways, with the joins staggered to give as smooth a surface as possible. The construction of these tracks is a highly scientific job, and the builder requires a great deal of experience before he is able to design a track which will carry high speeds. For this reason there are very few men in U.S.A. capable of building board tracks —in fact, there is, practically speaking, only one man. He is J. Pilk, who has made a study of tho problem since 1910, when he built trades for bicycle racing. At present tho two most important board tracks in America are at Charlotte and Culver City, the latter being about eight miles out, of Los Angeles, dose to the site of the old Beverley Hills track, lately dismantled. Both these tracks are of one mile and a-quartcr circuit. The record for one lap on the old Beherley Hills track was 126 miles an hour, while on the Charlotte track one lap has been done at tho rate of miles an hour. Both these records are eclipsed by the 155 i miles an hour put up on the Culver City track, where also a 250 miles race was recently won at an average speed of 126 miles an hour. It will be seen from these figures that the Culver City track is perfect from tho standpoint of speed. In view of the excellent performances of the American riders against their Australian rivals it would bo interesting to see how our riders would show up on board track radng—should there over be such a track laid down in Australia. FRONT WHEEL WOBBLE. Front wheel wobble is a defect which certain light, cars inevitably develop in their scion i or third season. Two or three makes of cars are notorious for the fault Others give trouble only after extensive use or abuse. A special effort has been made in the design of some of the .1925 models to eliminate the weakness. The use of balloon tyres and the fitting of front wheel brakes has in some cases aggravated the defect. Front -wheel wobble, at low speeds is usually attributable to wear in the steering gear or lack of eastoring action in the pivots, duo to a change In the set of the springs. Spring design has always been considered as an important factor in the solution of steering problems. A change in the setting of the front axle will destroy tthc balance of the steering pivots and induce unpleasant wobble. The handling of a ear afflicted with considerable front wheel wobble is most unpleasant. The motion may even be perceptible to the passengers. The oscillatory movement throws a great strain on the steering gear bearings. The smaller the distance between the springs, the worse the wobble is likely to become. In its initial stages front wheel wobble seldom occurs at all speeds. When a certain speed is attained it becomes apparent and it may cease if acceleration is continued. The application or the brakes often produces a violent wobble due to (he change in pressure on the front axle by the retarding action. The cure of front wheel wobble may not necessarily be costly. Tlie tightening up of the steering arms often suffices to eliminate the trouble. Where wear is advanced. it may be necessary to renew the brushings in the pivots. Where the set of the springs has caused the fault, it is required to restore the pivots to the correct 1

(linos of news —short descriptions of tours, the state of the ste., comment, or inquiries wiU be welcomed by “Accelerate*.

inclination to obtain the castoring action. The insertion of small wedgcs'bctwecn the springs and the front axle is a simple expedient effective in many cases. The wedge is arranged so that the spring does not lie flat on the axle. When the securing bolts are tightened up the front axle inclines slightly and re-establishes at pivot angles. . Neglect of front wheel wobble results m the speedy destruction of the tyres, and repairs will be costly if delayed for even a short time. A high speed wobble peculiar to a few cars need not give the driver much concern. The trouble may not occur until a speed of over 40 miles an hour is reached and at lower speeds it vanishes owing to the normal position of the axle and springs. EFFICIENT BRAKES. Any brake, to be considered 100 per cent, effective, should be capable of practically locking the wheels on a hard, dry, level road. This provides an emergency reserve that may seldom be required, but, in that emergency, a foot may save a life! says H. D. Hukill of the Westinghouse Air Brake Co., in a paper published in the Journal of the Society of Automotive Engineers, just out. The author discusses at length, the engineering principle of stopping vehicles and the limitations of the mechanical brakes now in use. “An average man," he says, “can exert a pedal force of approximately 200 pounds and pull of 150 pounds on a hand lever. Either hand or foot-actuated rear wheel brakes are inadequate to produce the shortest possible stop on any vehicle with a gross weight of more than 7500 pound!*. With the worst operating conditions, the brake-rigging efficiency may be. reduced to 50 per cent., so that a ear weighing 3000 pounds or even less could not bo controlled with foot or hand brakees. “When a braking pressure sufficient to lock the rear wheel brakes is not available, the addition of front wheel brakes will not reduce the stopping distance; in fact, because of the additional release springs and the increased rigging losses, the stopping , distance with four-wheel brakes is actually increased.’’ Believing that a power brake is essential for the adequate braking of vehicles weighing more than 50001 b, the Westinghouse air brake has been developed. It was designed to apply to existing brake riggings more force, with greater fleixibility, than is possible through hand or foot-actuated echanism*. The main elements include a steel reservoir tested to a pressure of 6001 b per square inch, a ball-chock valve connected with the combustion chamber of one of the engine cylinders, a pipe to load the pressure to the reservoir, a safety valve on the reservoir that opens at 2001 b pressure, brake chambers conncolod with the mechanical ’brake linkage, a foot or hand-operated air control valve, a rubber and fabric diaphragm that permits the air to expand against a push rod in the brake chamber, and metal brakeshoos that are not lined with woven brake linings. Tile brake chambers deliver push-rod pressures of from 3001 b to 15001 b at brake-pipo pressures of 601 b a square inch. With maximum application, tho braking force will be more than sufficient to take advantage of the maximum road adhesion, and the brakes will lock the wheels of a fully-loaded bus on a dry, level road. Tho flexibility of the brake valve allows the driver to control the action of the brake to any desired degree of intensity. THE FIRST MOTOR OAR IN MELBOURNE. The original machine which gave rise to tho modem motor oar could not have been viewed with greater concern and trepidation than tho first motor car to appear on the streets of Melbourne. The following account of its career and the excitement it canoed is given by Mr F. Thomas, of the Victorian cityMy father bought tho oar from Mr C. B. Kellow, who used it for throe months for demonstration purposes. I was only 16 years of age at this time, but I learned to drive it round Royal Park. The gatekeeper of Royal Park politely locked us in the grounds, which Mr Kellow did not like, but as it was tho first tiling tho gatekeeper bqd seen like it on© oould hardly blame him. After getting out we filled up with petrol at 9d a gallon, and started for Geelong, which Mr Kellow said was silly, and reckoned we would never get a« far as Worriboe. It was very dark when wo arrived at Little River. The engine was red hot, and gave us a bit of a fright. However, we arrived at Geelong in the early hours of tho morning. After a good night’s rest wo drove through the town, causing no end of bolting horses. People stood dumbfounded, and wo were very much disliked in Geelong. Tho following day wo gave rides at 2s each for charity. Wo bought the'car to be used in our business, which necessitated a lot. of travelling, but as we had' to deal with farmers the car was a failure, as they would have nothing to do with us in a motor car. Tho machine by this time had earned the name of the Red Devil. Tho farmers said that sort of thing was no good, as it would not oat chaff, and only frightened the life out of horsee and cattle. The railway s.trifc© followed closely upon this. Tho morning following the declaration of tho strike wo were approached by two gentlemen in Newtown and asked what we would charge to take newspapers from Geelong to Ballarat on arrival of the boat. Tile distance being 55 miles, it seemed a great feat to accomplish in those days. Having made the contract to deliver the papers at £lO a day, we started the following morning with a load of the Age newspapers, with which we arrived safe and sound. Tho papers were sold for Is 6d and 2s a copy at the newsagents. The telegraph office had warned tho agents that a motor car was on its way to them, and tho whole of Ballarat was out to see it arrive. Owing to there being a lot of strikers there they did not like the car being used for such a purpose, and after a demonstration had been made against it the police took charge of us and gave us full protection. But-for this there would not have been any more papers brought to Ballarat. There were several political men in Ballarat who wanted to get back to Melbourne. Among them was Sir John Taverner. The Bishop of Queensland was also there. I usually brought back a couple of passengers, which was not to the strikers’ liking, and one evening, when driving Sir John Taverner and others to Geelong, we were charged by a mob which stood in the middle of the road to stop us. However, I did not stop, but while we were passing them one of them struck Sir John Taverner on the mouth. Wo got to Geelong safely, and after staying the night there I brought my passengers on to Melbourne the following morning. During the run up both back tyres came off, and we had to finish the journey on the steel rims. There were no pneumatic tyres obtainable, so we got two solid rubber tyres at a rubber shoo and returned to Geelong. The strike finished that night. MOTOR CYCLE NOTES. On traffic-congested roads, ride so that you can see the signals of the driver ahead. Always put the right amount of air in your tyros. Only then can you expect to got full service from them. The new Coventry motor cycle, fitted with a 12 h.p. (175 c. 0.) and weighing only 1561 b, is capable of a speed of 60 miles per hour. By means of tho mechanical oil feed on motor cycles Ihe personal element is eliminated and the engine automatically controls its own oil supply. Tlie proportion of air and benzine introduced into tho combustion chamber, varies according to circumstances, but is usually between 14 to 1 and' 17 to 1. Tlie brake test of the 1000-mile English stock trial revealed more than anything else that brakes which are effective in solo machines arc for from being satisfactory when the weight of a side car and passenger is added. When in a traffic block, do not keep the machine in gear while holding the clutch out, it is easy for a fool to slip or a clutch wire may sometimes break. It is safer lo get into neutral if the stop seems likely to be more than a few seconds. A Californian motor cycle concern reports that it has recently equipped a number of motor cycle and sidecar outfits with radio receiving sets. It is stated that it has become quite a fad among Californian riders to have a wireless installation, which enables both passengers and rider to hear music and news, etc., while travelling, or while enjoying a rest in the country.