Hints for Buyers.
Page 21
Page 23
Page 24
If you've noticed an error in this article please click here to report it so we can fix it.
Points to be Observed when Choosing a Motoreab.
When the intending purchaser of a motorcab has decided to invest in one or more of these profit-earning vehicles, it is certain that he will -first want to know " What must I look for in examining a machine with the idea of pur
chasing? " Unless exceptional local conditions demand the embodiment of special features, we should strongly advise purchasers to take one of the standard models offered by any approved and known maker, as by so doing he both secures his machine at a lower price and can afterwards rely upon his obtaining spare parts for replacements which may be required. Having decided to examine a particular make of machine, with a view to its ultimate purchase, the buyer, or his technical representative, should carefully examine the whole of the working parts, the wheels, tires, and body.
Engine.
Commencing the examination with the engine, we should advise the purchaser to pay attention to the watercirculating system, and to note whether the circulating pipes are free from bends of short radius, as such bends are most undesirable in piping. The buyer should consider the piping arrangement from a hot-water engineer's point of view, and should bear in mind that, for efficient and unrestricted circulation, the pipes should be free from sharp bends. One pipe in particular should be noticed, and that is the return pipe from the top of the cylinders to the top of the radiator; on an engine which has its four cylinders cast en bloc, the cooling is often seriously impaired by its having the return pipe too small. When a pump is used for maintaining the circulation of the water, this, if of the centrifugal type, should be positively driven, or, if it is of the gear type, it should be driven through a torsion spring. Should any foreign matter find its way into the latter type of pump, there is great danger of a breakage if the drive is an unyielding one.
All belts which are employed for driving mechanical lubricators or cooling fans should be provided with some means of taking up the slack in the belt,, without need for resort to the make-shift method of cutting a piece out of the belt and rejoining the ends.
Our remarks regarding the water piping may be taken as equally applicable to all lubricator pipes : sharp bends in such pipes may often lead to a cessation of the flow of oil, and consequent damage to the bearing to which it is supposed to convey the lubricant. On the relative merits of the various systems of lubrication which are now in use, there is much diversity of opinion, but it will generally be found that pump lubrication gives complete sat isfaction.
• The position of the contact breaker, high-tension distributor, or magneto, should be such that they are amply protected from water, the presence of which leads to troublesome short circuits, with the usual attendants upon faulty ignition—noise, smell, smoke, and loss of power.
As far as the feed of the petrol to the carburetter is concerned, we should, except in very hilly districts, advise the use of gravity feed. This system is simple, because of the entire absence of exhaust-pressure valves and springs, which too often get out of order, but, unless it is possible to place the petrol tank very high relatively to the float chamber, the petrol may, on ascending a hill, cease to flow from the jet, and the result will he that the engine will be starved, and will probably fail at a critical point. On the other hand, pressure feed for the fuel is absolutely positive, and is not affected by the gradient up which the vehicle is being driven.
All the valves should be readily accessible, and when it is necessary to remove one for the purpose of cleaning or replacement, it should only be the work of a few minutes, and should not necessitate the undoing of a large number of bolts and nuts.
Bearings should be of ample size, and a buyer should never accept an engine which has short bearings, even though these be of large diameter. The cylinder and crank-case castings should also come under critical examination, and these should be free from sharp corners, or smal pockets, in which water, grease, and dirt are likely to accumulate. Sharp corners in cylinders, or in the water jackets surrounding them, are very liable to lead to cracks in the material.
Clutch.
The leather-faced, cone clutch is certainly the simplest, and is preferred by a very large number of experienced drivers, but a driver who can successfully manipulate a car which is fitted with a cone clutch will find no difficulty in handling a car which is fitted with a clutch of the multiple-disc type. The latter type of clutch has not the same tendency to drag as has the cone type, and, on the whole, it is perhaps easier to change gears with a plate clutch than with one of the cone variety. The function of the clutch is to connect the engine, in degrees of power varying from nil to the maximum, to the transmission mechanism of the car.
Change-speed Gears.
Unless the clutch and change-speed gears are enclosed in an extension from the crank case, there should be some form of universal joint, or flexible connection, between the clutch and the gearbox. The change-speed gears should be enclosed and well lubricated, and there should be some means of adjusting the selector rods.; the ,means by which this is effected is very importa on a vehicle which is fitted with an ei cyclic gear, as is the case with ti Adams and the " Lotis " cabs, or wi a friction drive as on the Certus in chine. With the sliding type, a sele tive, in preference to a progressiv means of changing the gears shou be chosen, because the first-named typ which is better known as the "gat change " type, is easier to operate, ar there is no danger of overshooting ti required gear, as is the case with change-speed of the progressive type. The epicyclic gear is by far the easie one to operate, and, after that, come the friction type, but, as we have a ready pointed out, both these types n quire most careful adjustment, the latter type is very wasteful of powt if the vehicle is driven on hilly road! Most gearboxes are now fitted wit ball bearings, and these should be a large as is consistent with the loa which they have to carry,
Combined Unit.
Among some well-known manufat turers, the practice of combining th clutch and the change-speed gear wit' the engine casing is becoming mor common, but we think that this featur may be carried too far, especially whet it extends to making the cylinders are the upper half of the crank case in on piece, as has been done on two of tie makes to which we refer in (hi! issue; unless the manufacturers can pu forward some very striking reason, o: point to some important advantage, a: the direct result of such a combination the prospective owner would do well t( take expert advice before he signs thi deposit cheque. We do not imply tha the grouping together of all these pare into one combined unit is bad in prin ciple, but the arrangement should bc such that the accessibility of all tht parts shall not suffer in any way, 01 that the renewal of any one part shah not become an unnecessarily expensive item. This warning is of special im• port to the small man who wants a few vehicles at most.
Joints.
All the universal joints on the cardan shafts and on the steering rods should be encased within leather covers ; these not only retain the grease, but they keep out the dust and grit which rises from the road. Metal cases are fitted to some cardan-shaft joints, but these are rather difficult to remove when necessary, and many of them are so affected by grit that they soon become practically useless.
Brakes, Steering Gear, and Spring".
Ease of adjustment, and protection from dirt and grit should be the first points for notice in the brake gear of P. motorcab. Strict interchange of the wearing parts should be guaranteed, and all cables or ropes should, as far as
is practicable, be avoided : steel rods are preferable to rope or cable.
Choose a steering gear which has ample wearing surfaces, and which is simple in construction. Many of the " improved" steering gears are so full of tricky adjustments that they are absolutely dangerous in use. l'roper provision should be made for the thorough lubrication of all the working parts of the steering gear, and this remark also applies to the spring-shackle pins.
Tires.
It should be remembered that, if the wheels are fitted with tires which are a size larger than is really necessary to carry the weight of the vehicle, the user will profit by the increased life of the tire, and the comparative freedom from trouble on the road. With a view to reducing tire trouble on the road to a minimum the buyer might, with advantage, consider the merits of special tire-filling materials such as " Elastes " and " Pneumatic." The former of these materials has now been thoroughly tested, and it has given a large measure of satisfaction.
The filled tire undoubtedly eliminates that great objection to the use of pneumatic tires for business vehicles—the liability to punctures. If, however, the purchaser prefers to have the pneumatic tire, he will be well advised if he also invests in one of the useful Stepney spare wheels, or insists on having the wheels of his vehicle fitted with a Parsons or other easily-removable rim, or some equally practical and useful attachment. Such fittings enable a tire to be changed in a very few minutes ; a fully-inflated tire, mounted on a rim, is carried on the vehicle, and, when one of the running tires is punctured, or otherwise damaged, it is removed, together with its rim, and is replaced
by the spare rim and tire which have been carried on the vehicle. Valuable time is thereby saved, and the earning power of the. cab is. not seriously impaired. The " K.T." tire, although not a pneumatic tire, in the generally accepted sense of the term, is practically equal, in point of easy riding, to the tires which employ air tubes and outer covers, and this we can testify from our own personal experience ; it should certainly be considered by all cab buyers.
Spare Parts.
Unless the cab is to be garaged in close proximity to the works of its builder, it will be necessary for the user to lay in a stock of such spare parts as are likely to be needed, but, in Lhe selection of these, he should be guided by the advice of the maker, who should know exactly which parts are most likely to need renewal. Such details as piston rings, valves, valve springs, engine bushes, brake blocks, and other similar parts which more or less rapidly wear out, should always be held in stock, in order to avoid any delay when any such parts require to be replaced. A selection of bolts, nuts, washers, and split pins, of the sizes which are employed on the chassis or body fittings, should also be held in readiness, in case any of those on the vehicle should be lost or damaged when making the adjustments.
Body.
The style and-finish of a cab body must, of course, depend to a great extent on the class of-work to which it is to be put, and it must be selected with this point in view. Nothing, however, should be taken for granted when making the purchase, and all such details as door catches, hinges, knuckle
joints, and other fittings should be most carefully examined, because it is in these small details, and in the manner of their attachment, that.. many makers attempt to effect a saving in the cost of the body. Wherever it is possible to attach the hinges, or other body fittings by means of bolts and nuts, these should certainly be used in preference to the usual type of countersunk wood screws, because the latter are bound to work loose in course of time through the creeping or twisting of the body when in actual service on the uneven surfaces which frequently serve as roads. Seat cushions and squabs should all be made removable, se that they may be taken out for cleaning and repairing when necessary. The buyer who is investing in more than one vehicle should see that these parts are all interchangeable, otherwise much time will be lost in the garage over the sorting out of the cushions for the different cabs.
It is the practice of the best coachbuilders to make the panels of the bodies in such a manner that any one of them can be taken out and replaced without disturbance of any of the other constructional work of the body. Now that sheet metal is so largely used for the panels, these may easily be made so that they can, when damaged by collision, be replaced without even disturbance of the paint of the other part of the body-work. The buyer of a motorcab should ascertain whether the body is so designed. The door should open freely and, when open, access to the body should not be restricted by any projecting part of the chassis, and the steps should be so placed that it is quite possible for an ordinary individual to enter the carriage without performing a series of gymnastic exercises.
Luggage Accommodation.
It will generally be conceded that the lest position in which to carry luggage s by the side of the driver, as in that )osition it requires the least amount of iandling, and it can more easily be ecured than if it were placed en the 1:spf. In this respect, and looked at rom the point of view of utility only, he Lotis cab with its 91 square feet luggage space by the driver's side is he best amongst the motorcabs which ye illustrate in the present number.
[he general arrangement of the Ausin cab, as we pointed out when we leak with that chassis in our issue of he 26th of March last, presents a fine 1>portunity for the provision of canentent and ample luggage spaces at ach side of the driver, lout the maker foes not appear to have taken aclvanage of this feature ; a very slight modiication of the shape of the chassis rame would make this cab the ideal no in respect of luggage capacity, as, ndeed, it is in most other respects. If, however, the luggage must be arried on the roof, access to the space hould not necessitate the use of lad.ers, or any strain an the muscles of he driver or porter, in order to place he trunk or other article in position. The driver of the old-fashioned growler an stand up on the footboard, or even on the box at of his cab, in order to put any luggage on the roof, but, with a tnotorcab which has a long canopy extending over the driver, such a means of loading is impossible. The designer of the Marples cab, which vehicle we illustrate on this page, has taken a lesson from the growler, and has made the roof strong enough to take a reasonable amount of luggage ; it is supported by six stout posts, four of which are the door posts, and these are not made to fold down when the hood of the cab is opened. The driver of such a vehicle is in the same advantageous position as is the driver of a horse-drawn growler.
Next, in point of easy loading, is the type of body which has but a short canopy extending from one-and-a-half to two feet forward of the front of the body. Two good examples of this form of construction are the Unic and the Fiat cabs, which are also illustrated. If a stoutly-made bracket were fixed behind, but not to, the dashboard, it would form an excellent step on which the driver could stand while be was loading up.his passengers' luggage on the roof of such a body.
The buyer must, of course, be guided by his own requirements as to the style of body which is to be fitted to the cab he purposes to purchase. The. general appearance of the many taxicabs, which are now in public service in London and the provinces, is as smart as many private carriages, and they are certainly ornaments in our streets.
General.
Many of the cabs which we describe in this section are fitted with live axles, and a large number of them have vertical, four-cylinder engines. Such an engine, undoubtedly, is more flexible, and puts less strain on the change-speed and differential gears than does the two-cylinder engine, but whether the saving effected in the life of the cab, due to the employment of additional cylinders, will more than compensate for the extra initial cost, and the cost of the upkeep of the motor, is rather problematical. The question, therefore, of whether a two-cylinder or a four-cylinder motor should be employed can only be settled by the nature and gradients of the roads on which the cab is to be worked : if it is to be employed on hilly roads, fit a four-cylinder engine; but, if it is to be used only for town work, where gradients are negligible, and the surface of the roads are passable, then, by all means stick to the two-cylinder engine—it has proved itself a reliable profit-earner in public service in London.