THE CHASSIS

Nelson Evening Mail, Volume LXIII, 20 July 1929, Page 4

THE CHASSIS

SEVERE TESTS $ s . • vf \ W m - •Many motorists are aware that, ear engines are .usually subjected to bench tests before being fitted .to the chassis; but it is not generally .Ihjjown that, in addition to this, the chassis ; . itself-’ sometimes undergoes a prolonged;; tdSti’ which verifies not only theytfhgine itself, but also the gear-box, .back..qjcle,, and all parts of. the transmission. i> . . This type of test, in : conjunction, of course, with the usual beii’ch test and followed by. a road test, has many obvious advantages over the. road test alone. -v ,• No matter how efficient a tester may be; he cannot, ojiv'ihe foad, fidd out minor imperfections: in the transipis-: sion, for road vihratibn must neCes-' sarily tend to minimise them.’ . When, however, tlie bare chassis is run -under on . a system • which enables the* power at the back wheels to be electrically recorded, expert examination can at once locate the slightest undue noise or vibration. Mass production, perhaps, may be frlamed-for.:a reliictance of some makers to perfection in this. way. Several of dry- leading, manufacturers; however, consider it more tnan s worth while, an example being fourkl in the Humber works at Coventry. Every model- there is subjected to a prolonged chassis test,-,after the engine has been “passed” and before the complete car undergoes a strenuous road test.' .• C,'S '

Take the case of the Humber Nine, a light car which is becoming increasingly popular, these .days. -As soon as a chassis is completed it Is fitted with a “slave” pair of rear wheels. The chassis-is then mounted so that each of the rear wheels bears on a, pair of rollers connected wish .dynamos.

After tlie engine has been wanned up iu neutral,, second gear is engaged iiud flic ear is run “light” for an hour. Top gear is then used for an hour, under load, at half throttle. For (lie remainder of the test—a further two hours — the ear is run all-out in top. During this time electrical readings of | the power transmitted by tlie back -wheels are taken. A definite power output for each chassis must be retarded and tlie transmission must condorm to a standard degree of silence. ;.j’ During this test the chassis is loaded, with a weight equal to that of the body and a full complement of driver and passengers. Apart from the fact, therefore, that the front wheels do not revolve,’the test is in all ways equivalent to one on the road, with the added advantage, that the transmission and so forth can be examined in a way impossible during road test. 400 M.P.H. CAR DESIGNED Everybody will agree that Sir Henry Segrave has done his bit for British prestige in motor racing. If his speed of 231 m.p.h. for the flying mile is beaten in America next year no doubt another gallant Englishman will step into the breach. At his reception in London in April, Sir Henry stated that had his previous record of 203 miles per hour not been beaten he would not have appeared in a highspeed ear again. Now he had regained the trophy for Great Britain he would never again take the wheel in a racing ear of any type. He had been lucky twiee, but might not be so successful the third time. It is interesting to note that the fast life of the Golden Arrow was only half an hour. Engine tests were, of course, made before the ear was assembled, but once it was in full order for the beach, trials, tuning, and the record-breaking runs did not aggregate over 30 minutes. Mr C. A. Villiers, a British engine designer well known in the motor cycle world, is credited with producing a design for a 400 m.p.h. car. This is the theoretical maximum, but the designer considers.’lie can guarantee 300 m.p.li. Eight driving wheels and engines aggregating 3000 h.p. are items in the design. The faet that such a car might cost from £25.000 to £30,000 is the first obstacle. The second consideration is to fiiid somebody who is willing to try if human senses will respond at the projected speed.

CAUSE OF ACCIDENTS Of a total of 20,022 motor crashes recorded in tlie State of California, U.S.A., during 1028, more than half--10,50 at street and road intersections, and 3220 of these happened because one of the drivers sought to cross without having the right of way. •• To reckless driving 2879 were attributed; speeding accounted for 2240, and driving on the wrong side of the road for 2030 others. “Cutting in” caused 1304 crashes, and in 1252 cases the ear left the road. Mechanical defects were blamed for only 922 and “that tired feeling” resulted in 208 lhisluips. • railway crossings 308 accidents occurred, while 432 cars were piled up against trams. ’ Wet roads were the cause, of 1245, and drunken driversamassed a tally’of 74. ! . ' , " CARE OF TYRES . ,ifTheJ.;.ojily reliable way of dealing -with tyre ■ inflation is to make frequent- of thef tyres with an efficient gauge. It is impossible for even an experienced: mechanic to tell by sight whether a tyre is sufficiently inflated; -If a tyre bulges it is almost certain that it needs- blowing-up, and it is most likely that the tyre has been run for hundreds of miles underinflated, causing irreparable damage to tlie covers. Inflation must be proportioned to the weight of load to be Carried; NEW MOTOR CYCLE STAND To overcome the difficulty which is often experienced in placing jnotor cycles .- on their stands ~a telescopic stand has been invented by Mr George Thompson, of Yorkshire, England.'Owingito the fact that there is-only a very slight lifting action as the stand pass-es-over tlie vertical position, the effort required to place even the heaviest machine on its stand is said to be practically nil; it is even possible for the rider while still astride to place the machine on the stand by graspng

the handle-barn and rolling the machine rearwards. When it is required to lift the tail of the machine, to tlie more usual height of several inches from tlie ground, in order to remove, for example, (lie rear wheel, the inner sliding members of - each stand can be quickly extended by slackening two grub screws, and tlie stand so lengthened. The stand can readily be fitted to existing machines, no alteration being necessary. CLEANING CHROMIUM PLATE Chromium-plaTcd parts may be much damaged by the, use of wrong materials for cleaning- Harm can be done by using such material as silver polish. The most efficient method is to rub t hi* parts with damp chamois leather, and to polish with a djy piece of tlie same material. It is a great mistake to use cleaning preparations without making quite sure that they are suitable. LAMP TEST OF BATTERY ■ The behaviour of the lamps is a good indication of the condition of the electric equipment. If the lamps flicker anil the ammeter is unsteady look for a loose’connection in the wifing or a loose contact between battery and generator, or bad contact at the lamp bulb, or a bad section of wire vibrating against the frame. If all lights are dim tlie fault is usually loose or slightly grounded connections, or poor connection with battery at the terminals, dne to corrosion. If in such circumstances the lights brighten when the engine is speeded up the battery wants more charging. Lamps which go dim when using the starter indicate that the battery is somewhat run down. Old bulbs will show dim light, due to the poor condition through long use of the filament. A sulpliatcd or corroded battery terminal may cause lamps, to blow out. Lamps of inaccurate - voltage will blow out or give poor light. POOR BRAKING FIGURES In a test recently carried out upon 400 ears selected at random from the roiuls in America, tlie minimum stopping distance from 20 m.p.h.- averaged no less than 40ft; more than double the figure that might reasonably be expected from four-wheel brakes. On only 11.2 per cent, of the cars it was found possible to stop in Jess than 30ft at this speed, anil 30 per cent, required more than 50ft. The investigators state that these poor results are m the main due to lack of care in brake maintenance, and arc not to be attributed to faulty design.