REMARKABLE TEST.

Press, Volume LXIX, Issue 20789, 24 February 1933, Page 7

REMARKABLE TEST.

10,000 MILES IN A FACTORY. How a new type of transmission was tested for 10,000 miles under the most exacting conditions in a factory is revealed by a well-known English firm. When, some ,time ago, it was decided to experiment with a free-wheel, a car was built up with this device and driven for some months by many testers and several members of the staff under the most severe road conditions it is possible to find in the British Isles. The intention was to run the car until the free-wheel device failed, but as the tests mentioned developed no sign of failure or wear it was decided that a moro intense test was necessary. As a result the experimental department evolved apparatus which allowed the free-wheel and clutch to be tested out for the equivalent of 10,000 miles running under conditions which were far more severe to these components than the same distance of London traffic. The engine, gear-box, and propeller shaft were coupled up to a dynamometer which gave the exact effect of the load of the rear wheels, and, on the overrun, the momentum of the car. A system of cams, electrically driven, was attached to the throttle and clutch. The engine was started up and the cam gear opened the throttle until 3500 r.p.rn. (equal to 05 m.p.h.) was reached. Then the cam closed the throttle with a snap, and at the same time the clutch was withdrawn. As tho throttle was again opened, so the clutch was engaged, aud the whole operation repeated—every 28 seconds. Tho "stationary car," as recorded by the dynamometer, was run in this-way for 10,00 miles at a maximum of 65 m.p.h. and an average of 4G m.p.h. The test occupied over 217 hours of day and night running, and during this time the throttle, clutch, and free-wheel were operated nearly twenty-eight thousand times. When dismantled the parts under test showed no wear whatever, and as the test could safely be taken as equivalent in severity to tho running lifo of a car under normal conditions it was decided to incorporate them in the production models. DRIVER TESTS. EXPERIMENTS AT HOME. The British National Institute of Industrial Psychology has been carrying out experiments —mainly on lorry and bus drivers—with a view to devising laboratory tests by which the "acci-dent-prone" driver may bo detected. The idea is to draw up a set of tests for a man's nervous reactions suitable for proving any latont "acci-dont-proneness," which might otherwise remain unsuspected until demonstrated by a series of accidents. For one of these suggested tests (saya a "Light Car" contributor) you sit in a cubicle got up to look like the interior of a car, with a view through tho windscreen of a pretty country lano. You start up, engage a gear and let in the clutch, and, behold, tho cubicle appears to move forward —in reality tho scene on tho screen beforo you is changing. As you steer and accelerate, an automatic- arrangement secretly records your course on tho roadway, tho speed with which you take the corners, and so forth! For another experiment you sit in a-pitch-dark room. At your hand arey three push-buttons; one (you are told) is for red, one for yellow, and one for green. Then spots of these three colours aro flashed successively on the screen in front, tho order being continually varied. As each light appears, the game is immediately to press tho corresponding button. Meanwhile tho exact time you take to respond is being recorded automatically. Then—with the coloured-light business still going on—a thrilling extract from a film i 3 suddenly thrown on the screen. 'Not unnaturally this causes a longer interval with most people in their but-ton-pressing. THE CLUTCH. SOLVING PROBLEMS IN NEW DIRECTIONS. Often in the history of car design we have had to wait until a particular component has been threatened with'obsolescence before it has. begun to appioach mechanical perfection. This was tho history of chain transmission, of the beaded-edge tyre, and of the fabric body, to mention three outstanding examples, and history seems now to be about to. reveal itself in the case of the clutch. For a quarter of a century the clutch which "wont in .with a bang, i unless it was carefully handled, and which was heavy and far from troublefree, was an accepted thing. We all regarded as necessary evils the long pauses in neutral which were "essential when changing gear, and the messy work i under the floorboards that maintenance I demanded. Wo used the clutch as little I as possible, and feared to coast with it released on account of the susceptibility of the spigot to seize and of the withdrawal race to "chew up." But now Avhen tho fluid flywheel and I the .self-changing gear threaten to displace the 'clutch from modem chassis, we find it free from all these faults. The up-to-date clutch is, indeed, so robust and serviceable that there is now almost a boom in easy-gear-change devices, which take the control of the clutch away from the driver and cause it to be automatically withdrawn and engaged with a frequency and ruthless.ness which would have spelt almost immediate de- ' struction to most of tho clutches of even five years ago. If, as it appears, the days of the clutch are numbered, will all the work which has been put into its perfection have been wasted? We do not think so, for its range of application is so very wide. Already, in fact, engineers are seeing in the present-day clutch a solution to other difficulties which changing fashions raise. In America, for example, the Society of Automotive Engineers recently considered a paper in which the possibilities of the single dry disc clutch were discussed in relation to braking problems which have arisen consequent upon road-wheel diameters threatening to diminish to a degree that would preclude the use of brake drums of adequate diameter. It was shown that disc-type transmission brakes had promising characteristics, and lent themselves readily to incorporation in a unit which would serve as a free wheel, a transmission brake, and a sprag. Lessons learned in clutch design are being used to-day in the design of crunk-shaft torsional vibration dampers, and they arc of value to all who are concerned with Ibe frictional applicat:ou of accelerative or retarding forces. The jcrkings and shudderings of: the cars of yesteryear as they reluctantly moved away from rest set in motion experiments which have had far-reaching consequences.—"Light Car."