MOTORS & MOTORING

Dominion, Volume 27, Issue 16, 13 October 1933, Page 13

MOTORS & MOTORING

(By

To clean a gauze oil filter wasli it in petrol and rub it lightly with a bristle brush. Do not. wipe with a rag, as particles of the rag are apt to adhere to the gauze, and may -later block the small oil pipes inside the engine.

Stop no more violently than you need. Skicis and collisions from the rear are caused by this practice, quite apart from the more rapid wear and tear of the tires. There is rarely virtue in showy methods.’

Change down for sharp bends. It saves your brakes, steadies the car, reduces the chances of skids and allows you to accelerate out of the bend more quickly, improving your average speed. It also gives you a reserve of acceleration and braking for any emergency which may arise.

DESIGN OF MUDGUARDS Methods of Preventing Splashing SOME NEW DEPARTURES / it is a common experience that some cars protect themselves from mud much more efficiently than do others, and to the owner-driver who does not wish to be continuously expending time and money on having his car washed, greater efficiency in mud-guard is much to be desired. Consequently, states a recent issue of ‘The Motor,” it is of general interest to examine the reasons which account for the fact that some cars keep clean while others soon become “plastered.” Consider, first of all, an orthodox saloon car equipped with the conventional system of wings and’running boards. After quite a short run on a wet road streaks of mud will appear across the rear door panels, soon spreading forward and upward over the front doors and windows. Furthermore, the outer surfaces of the rear wings (facing forward) soon become coated with the same obnoxious material. Obviously, this mud must, in the first place, have been thrown of! the front wheels, but the way in which it manages to reach the door panels and rear wings is not, perhaps, quite clear.

Mud Drips from Front Wings.

A certain amount can actually be transferred directly from the wheels to the panels when the car is steered, because few front wings are wide enough to cover the wheels when these are turned through a considerable angle for steering ■ purposes. Consequently, particles of mud thrown tangentially from the tires (as the tread leaves the road in an upward direction) are caught up by the air and become plastered bn to the coachwork. Some tire treads are worse offenders than others in this fault of lifting mud from the road surface.

Even more important a source of supply is'found in the liquid mud thrown up inside the front wings. If. the section of the wing is a simple curve this mud finds its way along the inner surface and drips from the vertical valance, whence it is blown backward on to the bodywork. Conditions are a little better -when the wing section embodies a central rib (forming a channel on the under side), but really efficient protection can only be provided by turning over the edge of the valance to form'd proper channel which will convey the mud harmlessly down on to the road. Unfortunately, this form of . wing is more expensive to pianufacture than is a more simple, but less efficient, section. New Styles of Mudguard. Here it is opportune to mention a style of front wing which has recently become quite popular, in which the valance (or vertical part) is extended and shaped to follow the curve of the tire. „It would, seem that this style has become popularised largely on the score of appearance, but, nevertheless, in point of affording protection from mud it has the advantage of diverting the air currents beneath it in such a way that the mud drips from a point much closer to the road than in an ordinary wing. Another new design which has a practical basis consists of prolonging the front wings forward and joining them with very big valances to the dumbirons. Many people dislike, the I appearance of these wings, but in point of mud protection, combined with a reduction of wind resistance, they undoubtedly present advantages. When a gar is travelling fast on a muddy road a great deal of the liquid picked, up by the tires is thrown off as they leave the road, but an appreciable amount appears to be carried round to fly off like the sparks from a Catherine wheel. It is for this reason that it is found to be advantageous to prolong the forward parts of the front wings. The so-called “close-up” wing, secured to stays which are bolted to the back plate of each front brake instead of being secured to the frame, has the advantage of turning with the wheel when the car is steered. Unfortunately, it is usually made so narrow, to achieve lightness, that it fails to intercept all the mud thrown from the tire. Furthermore, it cannot be linked up with a running board. < Some very smart designs of car have been brought out by discarding the running boards, but most of them are a nuisance, to say the least of it, from a «viewpoint of mud splashing. The important point to remember is that most of the liquid leaves the tire tread at a point quite close to the road, so that the rear part of the front wing must be prolonged, by means of a flexible flap, If there is no running board to act as an interceptor. Otherwise mud will be' spattered very liberally along th£ body. iXpart from the unsightliness, this fault is destructive of paintwork because ;i, liquid carrying gritty parti-

SPARE WHEEL.)

des, moving at a high speed, has an effective “sand-blasting” action. Importance of Streamlining.

Be it noted, In passing, that these front-end difficulties would not be so prominent were our ears streamlined more effectively than, at present. The front wings create a big disturbance in the air, enabling the mud to be caught up by eddies which converge upon the rear part of the car and deposit particles theron just as a river deposits silt wherever its free flow is checked by an obstruction. Now let us transfer our attentions to the rear encl of the car and follow out the subsequent history of mud which is thrown from the back wheels. On a really wet road liquid picked up by the treads rises on a curved trajectory and is caught up in the minor whirlwind which follows the flat rear panel of any moving vehicle. Here, in addition to eddying violently, the air is at a relatively low and the currents soon Impinge upon the rear panel, carrying the mud with them. Obviously, two methods are available to reduce the extent of this mudsplashing, one being to cut down the amount of material thrown off the rear wheels, and the other to secure a smoother flow of air and so to diminish the eddying wake. The first of these requiretaents is being met to an increasing extent on modern cars by prolonging the backward curve of the rear wings and by filling the space between them with a steel apron of generous proportions. As already noted, more efficient streamlining will eventually have a big effect on this mud-guarding problem, it being obvious that if the air were flowing smoothing over a ear of curved contours, free from projections, there would no longer be available the gusts and eddies by means of which any mud available is so quickly distributed over cars of orthodox shape. This applies v most forcibly to the rear-wheel problem. Thus, the modern close-coupled sports saloon, with a curved boot to till in the suction space at the back, does not create anything approaching the flurrying wake of the square-cut. saloon.

So far we have considered only the problem of protecting a car from mud thrown from its own wheels. There is. however, the complementary subject of protection from mud thrown from other vehicles. There are few cars which one can follow on a wet day without being liberally bespattered, and this arises largely through inefficient rear mudguarding which permits the mud to be thrown up and caught in the tail stream. It is easy to notice, on the road, the great improvement effected by modern cars with semi-streamlined tails and efficient wings.

Transverse mud-spattering Is another source of trouble, to vehicles and pedestrians alike. It arises mainly on uneven roads, the best example being stone setts in bad condition. Wherever there is a depression, shallow pools of mud and water collect, and when a pneumatic tiro drops into the hollow the disagreeable fluid is displaced sideways. , The files of the Patent Office can show innumerable inventions designed to prevent this occurrence, ranging from a simple baffle, swung from a bearing on the huh of the wheel, to more elaborate schemes such as a circumferential flap built on to the walls of the tire. None of these appears to have come to anything, and It must he admitted that most'of them would be both unsightly and expensive to make. The solution, therefore, appears to bo to keep I ho roads in good condition and to accelerate the process of replacing setts by more rnoden surfacings.