WINGS -- How They Protect
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Passenger Coachwork and Help to Create Good Appearance
ALTHOUGH the term " wing " is usually considered the correct expression to use, its synonym " mudguard " at once describes the chief function of this item of equipment. A well-designed wing should keep the mud from flying on to the body panels and, so far • as possible, prevent it reaching other users of the road, as well as the pedestrians on the pavement.
Before the days of the motorcar the wing was often referred to as a "dress preserver." It has this use when the wing is fitted close to a doorway, so that the guard acts as a screen between the muddy wheel and the passenger's clothing, or it protects the passenger from mud-splashes when standing on the step of a moving vehicle.
The best type of wing is that which follows closely the circumference of the tyre. The clearance between the tyre and the underside of the wing permits of the deflection of the spring when the vehicle is travelling over uneven surfaces, with a small additional allowance to prevent the tyre touching the wing when the vehicle is fully loaded. As sharp grit, which has dried out of accumulated mud, may adhere to the underside of the wing and projecting nuts may be present, insufficient clearance may easily cause damage to the tyre.
It is not a very difficult matter to design a wing so that it acts as a baffle to the mud thrown from a wheel in the direction of the length of the bus: the problem is to prevent the spray from working out sideways, owing to the force with which it strikes the wing. The c38 wing of domed section is more effective than that which has a flat surface. Furthermore, a closely fitting mudguard should be superior to that with a large clearance, but, on the other hand, the closer the wing is to the tyre the greater the air pressure which may be set up under the wing and the more difficult it is to prevent the mud escaping at the edges.
Wings are made either of wood or of steel. The type which is constructed of bent wood is employed because it is cheap and light in weight. As front mudguards are usually the first to suffer in minor collisions, replacement, if necessary, is not a serious matter. A fiat wing may be used for a service bus, but it is not suitable for the long-distance coach.
Wood wings Itre also liable to split and, if they be worth repairing, the operation is often carried out with a sheet of metal. This method of repair is a reminder that a more effective wood wing could be made by reinforcing the edges with a metal binding or channel. Plywood could be employed, either flat or moulded, so as to form a dome-shaped wing.
The steel wing has the advantage that it can be made in any shape. The typical front wing has an arched crown with deep side and front flanges, which help to throw the mud downwards on to the ground. The deeper the flange the greater its efficiency, but, in order that the wing shall not look unduly heavy, a moderate size of flange is improved considerably if a gutter, which is turned Inwards, be formed along the bottom • of the lip.
An important part of the front wing is its inside shield, which forms an enclosure between wing and chassis, and, in some instances, with the step and its valance. The inside shield is, in effect, a very wide wing with a flange of maximum depth, being shaped to allow the, wheel to turn the full amount of the lock.
Regarding the outline of the front wing, its forward end -,tiould not be behind a vertical tangent to the tyre. The rear portion may follow the circumference of the wheel, or be made with a return curve. The latter style is often preferred because it can be made to join up with the step of a front entrance. The outline is alzo more elegant, which is of importance when appearance is being especially studied. The return curve also helps to fill the gap between wheel and dash, and lines-up well with the body, when it has panels' extended below the top of the chassis.
The front wing is supported by means of a pair of Stays. As a large surface has to be kept rigid, the stays -are more effective if the flaps be of T or H formation.
If the body be of maximum width the wheel-arch forms a suitable wheel enclosure and, in some instances, a separate hind wing is hardly necessary, except for the sake of the pleasing appearance which is afforded by the projection of the wing and its flange from the surface of the panel.
With some of the smaller chassis the bodies exceed the track to, such an extent that a wing flange only tends to 'emphasize this difference in width. For this reason the upper half of the wheel may Be covered with a. fixed or removable panel, so that a paddle-box is formed. This panel conceals the overhang of the body at the top of the wheel and only reveals the difference in width at the bottom of the body, where, owing to the turnunder, it is reduced.
Paddle-boxing is also resorted to for enclosing the upper half of the driving wheels of the six-wheeler. In this instance the paddle-box may be used to hide what may be considered an Unsightly wheel-arch, or to increase the efficiency of the mudguarding.
The front panel of this paddle-box is made detachable, so as to facilitate inspection and the removal of the wheel. It is suggested that it could also be made to hinge, as a detachable panel may easily be damaged if left lying about in the garage for only a short time.
If the front of the wheel-arch be covered with a fixed panel, forming a continuation of the body side, it is presumed that there be sufficient clearance behind it for drawing off the wheel. This type of paddle-box, however, is not to be recommended, in spite of the neat exterior.
The wing employed inside the wheel-arch of the six-wheeler may form one large arched member, or have a double-arched outline, the latter helping to fill the gap between the wheels. The hind wing .for either the four or six-wheeled chassis has plenty of support from the surrounding body framework and special stays are oftenunnecessary.
Sometimes a leather flap or extension is hung from the tail end of the wing to intercept the lower streams of mud-spray, a similar arrangement often being attached to the front wings. As a further means for protecting the passenger when standing on the hind step, its front end is enclosed by a steel panel, carried upwards to the bottom of the body.