MOTORING

Evening Star, Issue 17329, 17 April 1920, Page 5

MOTORING

[By Carburettor.] ' Htief accounts of holiday trips j 7oads , and places of interest are invited for this column. IS BRAKE COMPENSATION NECESSARY? The question lias been raised in England as to whether brake compensation is necessary. By compensation is meant the mechanism through which the application of tne brake levers results in equal breaking force being applied tor both of the back wheels at the same moment. The matter is one of great interest to all motorists. One who was sceptical of the practicability of braking 'independently on one back wheel at a time conducted a series ot experiments, and his report makes interesting reading. ‘‘ I was asked to go out on a car in which the brakes were fitted independently to each rear wheel, having nrat been assured that very extensive tests had. been made on roads with surfaces of every description, and all that had been proved was that, while the braking system was exceedingly effective, far more so than on a standard car, there was no tendency to skid; m fact, the car pulled up in difficult circumstances with greater certainty and less risk than when the brakes on the same car were properly compensated, ihe proof of the pudding is always in the eating thereof, and I fixed on a clay which 1 hoped, under our normal weather conditions, would provide all the thrills desirable m _the way of first-class . greasy surfaces. Unfortunately, however, the weather turned out to be fine, and the only suitable place * or a test that could bo found was a main road, where the cement road wa-s beautifully polished; the kind of road on which i. one locked the brakes and spun the steering wheel round, the car would make a complete circle without hesitation. There is no need to mention the name of the car; there are at least two on which this braking system has been adopted, and there may be others Tbs tyres had identical treads—-that is, practically plain rubber—and the car was fitted with an ordinary type of differential gear. It should be said, however, that the car bad a rather Jong wheelbase in proportion to track, and is not, m the ordinary way, prone to skid. It was a four-seater, with the rear seats empfy. I approached the tests with an open, trame ot mind, and I must say that after through the experiences, which I shall presently relate, I am inclined to be in tavor of the arrangement. These were jue tests: The car was speeded 'up until *,O m.p.h. was registered, and we were proceeding down a gentle slope with a slight r-h lld left > wSlen tlle dm-er pu ] l(?d the off-side rear brake on hard. The car pulled up very suddenly, travelling in an almost straight line. 'Die locked wheel , " a skid _ mark on the road, and it was a.most straight for approximately 4a yards, tins mark was. clean, and showed no indication of skidding. Tho test was made agam tins time on a straight, level road and the foot brake was operated on the near-side wheel. The car pulled up in a rather shorter distance, and left a skid mark Which was quite straight. Then tests were made with tne driver leaving the steerin'* wheel free from the mommt the brake was applied until the car came to a standstill again. The car ran perfectly straight except that in the last few vards, when it neady stopping, .it pulled in to one side ot the road for a distance of about a foot. Ihcn both brakes were applied simultaneously, and I almost, shot through the windscreen tne car nulling up dead in 25 yards, then the driver tried a rather nerve-rack-ing stunt when the car was travelling at its maximum speed, for, as bo applied the brakes, he turned the steering-wheel first one way, then another, demonstrating that ha could drive, the car in any direction he hked while only one wheel was locked. , f result gave no cause for anxiety. The locked wheel left a snaky track from one side of the road to lb* other, followin'* the steering wheels premsely. At tho bends nt the skicrf murk the odees were Wean and sharp, with not a trace of skidding, yet one would have expected the car to have’ turned completely round. In all these tests the engma was declutched, bo I induced the i T e £ , mal: ? another test, leaving the clutch in. With an ordinary differentia! gear this has the effect of increasing the gear of tho wheel that is driving. Again the results were no different from tho foregoing It seemed impossible to make this car skid,, even with one wheel driving and tha_ other ono braking. It is worth remetn,benng that a parallel case is that of the side car, where the brake operates on the single driving wheel; yet it is notorious that the motor cycle and side car combination does not skid; in fact, it is the most immune type of motor vehicle. Since these tests wero made I have been wondenng if we havo not been accepting n practice which _ dates back, from early motoring plays without scientific investigation. Supposing the drive from the engine to the back aslft were freed, is there any reason why the car should skid because only one wheel is locked? Furthermore, if tho brakes are compensated acc irately, do they remain so for any length of time? My experience is most decidedly that they do not; and even if their action is simultaneous, would not that be negatived by variations in road surfaces with which the offside and the near-side wheels are in contact and m the treads of the tyres? The mor=> I trunk about this idea the more convinced I feel that we have been following a fallacy.”

While on the subject of brakes it might not be out of place to give the latest results on brake efficiency. These figures refer to the usual type of “compensated” brakes According to calculations which have recently been carried out in America to determine braking effect, the following figures have been evolved as the minimum dis-

~ lances in which a car can be pulled up at various speeds:—At 10 m.p.h. the distance will be 9.2 ft, at 15 m.p.h. ’the distance will be 20.8 ft, at 20 m.p.h. the distance will be 37ft, at 25 m.p.h. the distance will be 58ft, at 30 m.p.h. the distance will be 83.3 ft, at 35 m.p.h'. the distance will be 113 ft, at 40 m.p.h. the distance will be 148 ft, at 50 m.p.h. the distance will be 231 ft.

Sir Ross Smith and party’s great flight on the Vickers-Vimy from Melbourne to Adelaide—about 400 miles in a direct line—in 6j hours, serves in a way to emphasise what a remarkable drive Murray Aungcr put up over the interstate route between these two capitals. Aungor on his Dunlopshod "V an shall covered a distance of 594 miles by the route hq took, and had had roads and the sand drifts in the Cooroug to negotiate, yet drove from Melbourne to Adelaide in 14 hours 54 minutes. It was a wonderful performance, and one destined to stand undisturbed far many a year. The arrangements are already in hand for the Iridianopolis “ 500,’’ the longest motor car track race in the world. The conditions of this premier American ppsed event have been framed so that the weight of cars and capacity of engines will conform with those that are to be adopted for the next french Grand Prize road, contest — this evidently with a view of attracting tin? tastest cars from Europe for the corning event. The total prize money for the In“ynopol's contest is £IO,OOO, of which --4,000 goes to the winner. In addition, there are a number of other valuable prizes donated by various American accessories and tyre manufacturers, which brings the victor's cheque up to close on £6,000. The event is to be decided on May 31. A Trench car, the Puegoot, carried off the last two events.

It is reported from France that the weil"nowu aviator Sadi-Lacointe has been timed ,*■? ijlOOyds over a measured course at the amazing speed of 227 miles an bom-. . Reserved judgment was given at Nelson m a case in which a man was char-red with driving a motor car -on the Haw a road at a speed greater than 12 miles an hoxir, contrary to the Nelson citv bv-laws Ine Magistrate, Mr Evans, held" that the by-law m 'question was unreasonable and void, and dismissed the information. V‘ € r Automobile Club of Victoria held their first sporting event since the openitm ot the war, the contest being a hill climb at »Vilciwood- That the event was appreciate - ] was shown by tho fact that 400 cars visited Um scene of the competition, and all told spectators -witnessed the drives against V m . e , I'P * lle gradient. Six evenis were decided, five of them being divided into two classes, according to horse-power of eugincs. t aluable trophies totalling about -.to were awarded to the winners on formulae aim also to actual fastest time winners in the respective classes. One of the most striking performances was the success achieved by a pre-war 6 h.p. De Dmii. •tastest tunes were recorded by a Hudson and a Buick, who tied in the chassis class. A very fine motor cycle performance Mas registered lust week by the N.S.W. rider t. Berry. Driving a llarley-Davidson sidecar outfit with a passenger up, Berrv tackier the side-car record botM-ecu Sydney and Melbourne (565 miles), which stood at ril hours 59 minutes to the credit of H 1 arsons (Vic.). This lime Berry reduced oy 2~ inmuies, Ins gross time from canital to capital being 20 hours 38 minutes. The motor cycle record for this route is vet a long way behind the car time for the course, B. Elkins, tlio holder of the record, having negotiated the interstate run on a 1910 Ul k° urs ln *nutes in March,

The output of the Ford Company, of t-annua, from whence the Australia]} Ford supply is derived, has been reduced from to 100 cars a day, owing to scarcity of tabor.

.It is stated, that motor vehicles in America cover 60,000.000,000 miles tier annum, against 35,000,000,000 passenger miles run by tno railways in that country. The half-day trial which is’ being held to-aay should prove a severe test for machines and riders. The course has been chosen with that object in view. Although 1 happen to be a member of tho Awards Committee, and expect to fco taking one of tue checks at the time of writing, I do not snow the course. That is to be a b-ecret- one, and the secret is we'd kept.

According to advices received in Dunedin • *‘ lere ‘ s 1° he an all-round rise m Lritisn cars and motor cycles. Although doubtless unavoidable, from the motorists standpoint this vs a matter for regret. One of the first P.nglish post-war model cars to arrive m the Dominion is due in Dunedin by the Tainui shortly. I have been pnviliged to read a loner from the t-alcon, agents, who M-rite: “ Subject to nouimg untoreseen occurring, we Imps to obtam delivery from Calcott's of the first sample demonstrator for yo t on or about December 20, and if we can connect wi*h the steamer that is leaving prior to Christmas, we shall _he only too pleased. Under present conditions wo cannot be definite, but the tact that the second machine brought through too works has been allotted to yon Will show that Calcotts, as well ns cmrwre a ', ,xio '.’ s to do their best." iho will not be long before- thov have tneir own chib rooms. An energetic committee have tho preliminary nrraneoments .-a hand, and are on the lookout for a suitaole building Wbar is being sought, tor is a building w’ir.h a fairly large spn«ce ou ’•? ground floor ror garage accommodation and room above for two billiard tables, reading room, board robin, secretary's office and_ batnroom. It is not intended to go in tor general garage work, such as ivpairc. etc,, but room is needed for club members—city, suburban, and country—to leave their cars when in (own during the day or in tho evening. Such a building has proved almost invaluable to the members of the Pioneer Club in Christchurch, and should prove equally serviceable to Dunedin.