SCIENCE AND TOPICS

Bay of Plenty Times, Volume LX, Issue 11046, 21 February 1933, Page 3

SCIENCE AND TOPICS

Modern Tests for Motor Cars THE BUMPING RIG. The scientific testing of motorcars and tbeir component parts is considered essential nowadays for the maintenance of a high standard of motoring comfort and safety. One firm of manufacturers recently set out to find the most vicious method of testing the chassis of a car. After much experimenting they discovered what they considered to be a test which would reveal any weakness.

In this method, known as the “Bumping Rig,” the front wheels of a chassis are placed on two rollers on which are steel bars at different intervals. These rollers are rotated at a speed of one hundred and five revolutions per minute and, as each bar hits the wheel —and the two wheels are not hit at the same time—the spring receives a terrific jolt. This test is equivalent to driving a chassis over the worst of roads, and each chassis is subjected to the test for about one hundred hours. Another firm have been investigating the claims made for new metals which might be suitable for cylinder construction. For five years this firm’s research department have been experimenting with alloys with a view to prohibiting the excessive wear which has become recognised as almost inevitable in the modern high speed engine. The moment the metallurgists were satisfied that they had solved the problem, engines were constructed from the new metals and were subjected to continuous night and day tests under ordinary road conditions. When three cars had completed thirty thousand miles each—the equivalent of three or four years’ average running—the engines were dismantled. The result was that practically no wear could be detected by instruments capable of measuring *to less than a tenth part of one thousandth of an inch. Usually, after this mileage, an engine would need its cylinders re-grbund, and over-size pistons would be necessary. The new material, which is a chrome alloy, has now been adopted for general production by the firm in question. The employment of this alloy reduces oil consumption to a minimum and prohibits the development of mechanical noise. In addition, distortion is so negligible that valve grinding should be seldom necessary. One of the latest scientific theories relating to motoring suggests that a car driven hard but well should give longer service than one which is driven at low speeds. To test this theory a sports model was selected for use first as a demonstration car and later as a general works “hack.” After being driven hard for two hundred thousand miles it was found that the car was still capable of running perfectly and silently with normal oil consumption. The experiment proved that if an engine ie driven fast and well less wear takes place than if it is driven slowly and well. Driving slowly and erratically, stopping and starting, are the main causes of engine wear. It is contended that in the first five minutes of starting up an engine from a cold condition, more wear takes place than in twelve hours of fast running. Modern methods of testing indicate that high average speeds can be recommended to the motorist provided that he carries 1 out the necessary maintenance work on his car regularly and carefully. If a car is driven fast but carelessly it will soon begin to lose its efficiency. The safe use of speed is dependent upon good gear-changing, skilful braking,, and adequate maintenance attention to all parts of the car. Motor-car racing is another form of testing which ultimately helps the private owner-driver. Under the gyuelling conditions of a race everything on the car is tested almost to its limits. Cylinders, pistons, bearings, transmissions, wheels, gears, and so on, must be of the best types obtainable. And when the best is inadequate for the work something oven better must be produced. In this way racing cars have progressed in construction and design, and the principles which have been evolved for racing are adapted for the models which the owner-driver uses on the roads.

Light pistons, high-compressions, close ratio gear-boxes, improved, braking systems .. . these-are just a few of the motoring benefits for which the private driver must thank the intrepid racing man and hie scientific colleagues. Larger steering .wheels and more comfortable driving positions have become features o/ the modern popular car chiefly as a result of racing experience.

Weight distribution and controllability must be as perfect as possible in a racing car, and the attention which has been given to these items has influenced greatly the general trend of car design.

Few motorists realise that safety on'the road has been achieved largely by lessons learned on the track* The hazards of racing combined with scientific observation and research work, have made the popular car Increasingly safe.