SHOWING PROGRESS ITS PACES

King Country Chronicle, Volume XXX, Issue 4874, 23 July 1936, Page 8

SHOWING PROGRESS ITS PACES

THE MODERN CAR. General Motors hias issued a most interesting publication covering in graphic form the various methods adopted at the Company’s proving ground in testing the products of this organisation. The proving ground was established in 1924 and covers 1268 acres. We publish a few extracts from the booklet:— AN EAR TO THE MOTOR. As the engineer “listens in,” he is able to make an unqualified determination of noise intensity over the full speed range of the car. With his audiometer, he can search out annoying sounds and trace them to their place of origin. EYES. All of us realise that vision is a vital factor in driving. When our father climbed from a horse and buggy into a horseless carriage, our problems in vision increased. A very valuable pair of eyes had been sacrificed. No longer could we rely on old Dobbin to [help guide the way—we perform the task ourselves, and because, of the inherent nature of our vehicle we see a good deal less of the road than did our faithful horse. SPLIT SECOND. It is difficult to be matter of fact about a speedway. Even the hardboiled testing engineer who practically lives on one, feels the drama — some of the desperate struggles that are necessarily associated with it. You can talk about parabolic cross sections, spiral leads, thirty-four degree super-elevations and thousands of tons of concrete, but you forget and remember a single fleeting instant when a projectile of steel on wheels flashed by and droned into the horizon. You are .not interested in the pages and pages of elaborate computations made by the engineers or in the difficulty involved in pouring a piece of parbolic pavement wide enough for eight cars .to drive abreast. You don’t care if the track is 3.8 miles long, if it is is the finest speedway of its type in the world. You only retain a composite mental image of a car living its life in a few hours, the smell of the track, the roar of the engine and the scream of the tyres—motor vehicle giving its all in a gruelling, relentless grind—martyrdom, if you please, so that your vehicle and thousands of others might live a little longer. ENERGY TO HEAT. “The law of conservation of energy stipulates that energy can be transformed from one form to another, but that it cannot be destroyed.” Momentum is one form of energy and heat is another. A car builds up momentum as the speed is increased. When we stop, something has to be done, with this energy. Since it can’t be destroyed, we convert it into heat. That is all the brakes do. They change momentum into heat. Now there’s a lot of momentum, to a vehicle travelling 70 miles an hour. If we wish to stop a 3500 pound machine as quickly as we can (which, incidentally, requires 4.2 seconds), we must absorb 329 horsepower in the brakes. That is a lot of power. It would be] enough to lift our vehicle 165 feet off the ground. It is easy to say, therefore, that our brakes must do a tremendous amount of work in a day’s drive.