Some Wonderful Six-wheeler Facts.
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HROUGH the medium of our news-columns we have kept our readers advised of the important experilnents that were 'being conducted by one of the leading tyre and rubber manufacturing concerns in the United States, in order to ascertain whether the theciretieal advantages of spreading the load over a greater number of wheels than four would he borne out in practice.
The aim and object of these experiments was the encouragement of the. use of pneumatic tyres, in order that the claim to legislative amendments to the existing speed regulations should have behind it the sound justification of reduced wear and tear of the road surfaces and of lessened damage to the foundation of the roads. The experiments have been extended over a period of nearly two years, and, as we show in our special article on the subject, a total distance of much in excess of 60,000 miles has been covered by the seven vehicles that haveMseen built.
We have been able to secure considerable data from the experimental department of the concern in question, and, with the illustrations which we have prepared in order to amplify the descriptions of the vehicles and of the axle assembly of each, we think that a good case is made out for (I) the tweed components of such lightness that, in conjunction with the employment of pneumatics instead, of solid tyres, there is an actual ,saving in unsprung weight ; (2) the assembly of the driv.ing axles so. closely together that the amount of slip of the. _central axle (in the absence of any provision for steering the wheels mounted upon it) is -small, and is compensated for by the warp of the tyres ; and (3) the expectation of but a small increase in cost of chassis eimstruetion, what there is being due to the employment of pneumatics which would actually have the effect (this is proved from figures obtained over 40,000 miles of running) of bringing down the costs of running and maintaining a 5-tonner till they approximate to the figures pf a 312—tormer.
These are extraordieary facts, which lend considerable support to our arguments in favour of an increase in the number of axles on (for a start) all commercial goods and passenger vehicle's. In addition to the arguments advanced in the article appearing in this issue, we have in our possession some important data, obtained from a, series of tests made by order of the United States Government, which show that the six-wheeled pneumatic-tyred 5-tonner is less destructive of road surfaces than the standard 2 ton vehicle, even when the latter is also mounted on pneumatics. Our next week's issue will contain much important information concerning this question, of reducing road damage. When we consider that the country has spent 252,000,000 in the upkeep of the roads for a single twelvemonth, and that every farthing of this has been extracted from the pockets of the ratepayer, and has helped to increase the cost of all commodities, we must admit that any sound proposal, such as we are now putting forward in The Commercial Motor, for the reduction of this impost, deserves the fullest consideration of the Ministry, the manufacturer, and the user.
Crude Oil Engines for Transport Vehicles. IN this issue we publish details of an interesting type of semi-Diesel engine which has been developed for use in motor vehicles. It has long been the ambition of designers to produce an engine of this type which, while. being capable of utilizing as fuel almost any kind of crude oil, will have a power-to-weight ratio sufficiently high to enable such an engine to be employed without unduly increasing the total weight of a vehicle. Until now, this question of weight reduction has been the stumbling block of many. The very high compression and explosion pressures which. are attained necessitate extreme strength throughout, and we well remember that in a similar type of engine which was developed by a British inventor some years ago, it was found necessary to fit a stout armoured dash, in order to prevent flying particles of engine from injuring the driver. We also believe that several times explosions occurred with this engine which actually blew holes in the road. It will be seen, therefore, that, apart from. the question of efficiency, that of safety must receive due consideration. It is unwise also to increase complication or to rely upon extra attention from the driver. Such engines must, therefore, be practically foolproof, and in that which we describe it would appear that this desirable feature has been almost, if not quite, attained. It remains to be seen whether the road tests made with the vehicle embodying this power unit will confirm the satiao fa ctory results which have been achieved with the bench tests made with it.
There is no doubt that if this engine achieves any considerable success it will be followed by others of a similar type, as the question of cheapening fuel costs is being raised on every side, and if crude oil he employed the supply will not only be much cheaper, but will he greatly increased, because petrol forms only a small portion of the total volume of crude oil, a i nd f we utilize the latter we not only save the cost of refining, but also have far larger quantities of fuel at our command.
December Deliveries Held Up Through the Licensing Regulations.
WE should always' we are told, be thankful for small mercies. And in that spirit, therefore, -we receive the concession in the matter of instalment payment for licences which the Transport Ministry intimates will be permitted early in the New Year. It has not, perhaps; been realized how serious has been the effect upon sales of new machines of the high incidence of licence charges, under the present regime, for machines bought to put into service towards the end of the licence year. It is probably no exaggeration to assert that this state of affairs, nonexistent in the days of the petrol tax, has held up manufacturers orders to the tune of many thousands of pounds. The new monthly proportionate scheme, 54 although an advance in principle and of some advantage to the user, will, undoubtedly, still act detrimentally to a considerable extent upon the placing of orders for new vehicles. The charges for the convenience are too .high as well.
Is there any logical and tenable reason why vehicle licences should not be issued, say, for quarterly, sixmonthly, or yearly periods at any time of the year, on any date in the year? It is stated that neW proposals of the Ministry of Transport will necessitate a very considerable and more or less permanent increase in staff to deal with the greatly increased numbers of individual applications which are anticipated. In one northern county central licensing office over 20 extra girls will be required, it is stated, for a considerable period. Now that the identification of each machine is so easily secured and the currency of its licence so publicly advertised, there does not appear to be any reason why a licence should not commence on any day convenient to the licensee, just, as, for instance, do the public-carriage licences of Scotland Yard and similar authorities. Any passenger in a London General bus can see for himself the date on which the machine will have to be presented for relicensing.
The abandonment of the December 31st period would avoid congestion in the licensing offices by spreading applications over the year, and, combined with the issue at slightly enhanced but properly proportionate rates for short periods, should achieve maximum public convenience as well as minimum trouble to the licensing authorities, and should remove the present damaging effect on orders for manufacturers during the closing periods of the existing licence year.
Why should not a dog licence, obtainable-at any time of the year, be current for the ensuing 12 months? Presumably because of the difficulty of identifying the owner of an individual dog with his individual licence period—unless the dog wore the licence. But, the motor vehicle wears its own licence nowadays.
Wasting Engine Efficiency. THE modern motor vehicle is a marvel of efficiency and economy, but it only remains so if used reasonably and if treated with care. However efficient the engine may be, much of its power may be expended vainly, and, if fuel economy is desired— and very few users do not desire it—it is essential to pay attention to many small points -which, singly, may not be of great importance, but in the aggregate may cause quite an appreciable waste of power.
Dragging brakes is a very prevalent fault to which drivers often pay little regard, and, apart from wearing of the friction linings, the petrol consumption of the vehicle may easily be increased 20 per cent. by this cause.
The use of thick greases in gearboxes and back axles may not appear to the casual observer as affecting in any way the efficiency of the-vehicle, but the amount of heat often generated by the churning action of the greases shows clearly that here is a serious loss. Particularly is this so in winter, when the grease becomes partially congealed. With the engine also the use of too thick a lubricant will materially increase the friction between the pistons and the walls of the cylinders, • and the efficiency power losses are thereby increased. In the same way lack of attention to the laminated springs will cause the plates to rust and bind, and the springs, becoming hard, will not only cause increased vibration and undue stresses on the whole chassis, but will also increase the petrol consumption, owing to the rebounding and consequent spinning of .the,,rear wheels.