MOTOR AND CYCLE.

Taranaki Daily News, 10 June 1922, Page 11

MOTOR AND CYCLE.

NEWS AND NOTES, The opinion of Mr. S. F. Edge, who has so long been associated with motoring in England, as a racing man and a manufacturer, is always worth considertion. In a recent issue of the Auto Car he makes some interesting statements in reference to the design and functioning of springs, which we reprint. Long, long ago, I came to the conclusion from driving and using innumerable cars that, other things being equal, fla.t or flatter springs were more comfortable than deeply curved ones. When T say “other things being equal,” 1 mean such things as springs being adequate for their loads, and generally standing up, tyre pressures, upholstery, wheelbases, proportions of unsprung to sprung / weight, and the thousand and one other contributing points which go to make up the comfort, or comparative comfort, ox* discomfort, of the average car. Curved springs, for one thing, were always “suspect" to my mind, because undoubtedly in the early days, as inherited from the hackney carriages, etc., they were largely made in a curved form to give clearances for straight frames, etc.; indeed, it was the usual practice I believe, in many drawing offices to design the chambers on their springs as a sort of last dying effort to give their cars the necessary clearances required between the various parts and the ground and axles. Indeed, I remember in the early days, I have frequently seen cars with blocks of wood between the axles and the springs to add to this clearance without a re-design of the vehicle. Of course this was not a very scientific way of doing things, but such curves and shapes would be apt to be inherited. Clearly, therefore, the deeply curved springs more than possibly have “just happened.” At least, to me, this has always appeared a possible explanation for the deep chamfoer of some road springs still in use to-day. Some firms have evolved further than others, and freed themselves from this “state of mind,” but here again, mainly bv accident. The probability is that flat springs, which are more comfortable, have evolved from the deeply curved type chiefly through the desire to get the centre of gravity lower by the general lowering of the frame. At least it is more than likely that this is the way in which a really very desirable alteration has come about without our engineers realising why. The reason. I think, why the flat •spring is more comfortable is merely that the axles and wheels running on the road can influence a flat spring to bend more rapidly and quickly, other things being equal, than a deeply curved spring. Tn other words, the wheels can rise a given distance vertically with less disturbance of the spring. To put it in another way, a flat spring is practically at right angles, or nearly

horizontal to the nearly vertical line , that the wheels take when they bounce or ride over an obstacle. Therefore, they have not to flex more than the movement of the wheels themselves, whereas a deeply curved spring has to flex (shall we say?) backwards as well as upwards, for a given vertical rise, and increased resistance is the result through the increased movement. Mv idea of a spring is one that is very flexible. The wheel, say, comes across an obstacle, rises rapidly, smoothly, and easily without giving the ear a terrific tug in the process, because the spring “thinks quickly” (if I may be allowed the term), sees what it has to do and does it. The same wheel comes across a hole the next moment, and endeavors to follow the road instead of bumping across to the other side of the hole; indeed the conditions under which a valve tappet follows the earn on the camshaft are not very dissimilar from those of a wheel running along an uneven road. It is probable that periodicity of springs and all the thousand and one technicalities in which the subject of springing is hidden and sjirouded are all upset bv the fact that when one is travelling fast on a rough road with an irregular surface with neither rhyme > nor reason, its irregularity upsets all calculations, and the whole thing resolves itself into a mad tussle between the car, with its dead weight tending to travel on an even keel, and the wheels jumping up and down obeying the blows they receive from the road, the road springs tugging them back into contact with the road, and, of course, reacting on the car. In brief, I propound the theory that the flat or flatter springs are more comfortable than deeply curved ones, and the basic reason for this is that the wheels and axles, other things being equal, are mechanically in a better position to influence flat springs more easily than deeply curved ones, for the simple erason that the springs themselves for a given vertical rise of the wheels have to flex less. I wait to hear this view torn to pieces by the engineers. At any rate, it is a reason for preferring flat springs, and no one has ever yet given me a logical reason for preferring flat springs or against curved ones. Further details to hand in connection with Bovd Edkins’ unsuccessful attack on the Brisbane-Sydney motor car record last week show that Edkins was “up against” trouble most of the journey. He had to contend with rain and wet roads —those who have driven a car stripped of mudguards, will know what this means, over a considerable part of the journey. In some places the climbs and descends over the ranges were particularly greasy and trying. Despite these conditions all would have been well, and the record secured only for the fact that a section of the road between Windsor and Parramatta (only 30 miles from Sydney) is under repair, and the traffic has to run on a side track, not very distinct in places. In the dark the car ran off the track and dropped into a 7 foot hole. Y little damage was done to the Vauxhall beyond breaking the starting handle and a head light, but it took 20 men and 6 women about 4 hours to get the car inch by inch out on to the track again. Edkins is so confident of getting the record, despite the lateness of the season, and the short period of daylioht available, that he intends making a/further attempt at an early date.