THE
Page 39
Page 40
If you've noticed an error in this article please click here to report it so we can fix it.
COMMERCIAL MOTOR
Recognized in Business Circler, as the Leading Journal.
The Authority on all forms of Mechanical Road Transport.
Largest Circulation.
Conducted by EDMUND DANGERFIELD.
WE continue, this week, our article dealing with the experiences of passenger-vehicle owners with pneumatic-tyre equipment. Further interesting figures are given, and the results are collated and analysed.
Page 938.
AN interesting, if brief, survey of the development of the omnibus in Paris during the century which has elapsed since M. Baudry placed the first of the type onthe road in 1828 is given under Passenger Travel' News. Page 984.
WE give the licence statistics for the twelve months ended November 30th, 1927, showing that the number of commercial motors in use was 450,433 out of a total number of 1,656,932 licensed motor vehicles in the
country. Page 942.
THERE is no such thing as finality in the design of engines. Even quite simple means for effecting improvements are now corning to light, and we deal with one of these, which is claimed to permit compression pressure ratios of 8 to 1 or over. Page 924.
OUR Parliamentary Correspondent in the Press Gallery of the House of Commons, who, on the reopening of Parliament, has resumed his weekly notes, announces the decision of the Government to abandon the Road Traffic Bill milli after the general election, which is due in 1929. Page 923.
WE describe a new 8:10-ton tipping trailer, the tipping of which, despite the heavy load, can be operated by hand, a pump, actuated by levers, forcing water to the base of a ram, the water returning to a small tank pounted in front of the chassis, when gravity lowers
the body on to the frame. Page 925.
THE article which occupies our centre pages deals with the extraordinary differences between the comfort provided on early passenger vehicles and that afforded by the most recent moJels. It is pointed out that there is still more to be done in this direction, and some interesting suggestions are made. Page 960.
NEWCASTLE and Gateshead form a most important centre from which radiate a comprehensive network of bus services, not only expanding over long distances, but particularly within the immediate area to the extent of 50 or 60-mile journeys. We deal with the short-distance services in an article in this issue, the long-distance routes having been described in our Passenger Vehicle Number. Page 925.
WE refer briefly to a visit recently paid by us to , the wharf and refinery in London of a well-known concern specializing in lubricating oils. Apart from its • technical interest the place has a history, for it was " one of the first (we believe Off; first) oil refineries to be established in this country, t-Incl during the war was • slfatfered when an adjacent T.N.T. factory was blown up, almost devastating tile neighbourhood. Page 929.
Have We Reached the Limit of Efficiency in Engine Design ? .
-D13.0GRESS in the development of petrol engines •capable of producing great power per unit of swept cylinder volume, and this at a remarkably low consumption of fuel, has been most rapid during the past two or three years, and it may be thOught by many that we have almost reached the limit of efficiency in certain of these englaes, so that, unless some radical change be made in the design or tile operating cycle, as in the case of the -production of a practicable internal-combustion turbine, finality in design has almost been achieved.
In our opinion, however, we are a long way off finality in this as in most other mechanical contrivances; engines far more efficient than those commonly employed .in commercial work have been constructed; but in these power units, which are intended for specific and unusual work, such as racing, this efficiency has only been obtained at the expense of smooth running and engine. life, whilst the high compressions employed have rendered essential the employment of special antiknock fuels.
We refer to these points for the reason that there is at present in course of commercial development an engine utilizing a normal four-stroke cycle in which, by the employment of air or mixture cooled in a novel manner, compression ratios much higher than -those usually employed are permitted. An experimental engine (which, incidentally, is described in this issue) is stated to have given good results on a compression ratio of 8 to 1, another engine with a much higher compression being now under construction.
Whether the claims made for this unit can be justified under actual service conditions remains to be seen. It Certainly seems rather extraordinary that the mere cooling of a charge before its normal compression in a working cylinder changes conditions so radically that such high compressions can.' be obtained without pre-igniting the mixture or causing excessively harsh running. It may be that part of the alleged success of this engine is due to initial compression and expansion given to the mixture before it is fired, as this. may have the effect of atomizing the liquid fuel in a more thorough manner and so producing a more homogeneous mixture.
If this new invention provesto be a success it c17
will be one more example of what can be done in the way of modifying an engine of quite normal type, not by making great changes in the engine itself, but by employing what are, in effect, extraneous means which may be classified with the supercharger,
The Claim for a Reduction in Motor Taxation.
FROM the eight million sterling which was contemplated as the appropriate annual amount accruing to the national revenue from motor taxation, the figure has risen in but a few years to £22,297,000. The full amount of the receipts of vehicle taxation for the twelve months to November 30th, 1927, was £23,456,378, but it is necessary to deduct £368,000 in respect of rebates, refunds, etc., £90,912 the proceeds of taxation on tramcars and horse-drawn vehicles, and £222 taxation on invalid cycles. The owners of motor vehicles thus pay a very substantial sum annually to the Exchequer, far in excess of what is reasonable, because they already bear the full burden of citizenship before the extra impost is levied upon them for the use of the highways.
Now that the sum of £20,000,000 as the net proceeds of motor taxation has been exceeded, the motor owner is justly entitled to a full reconsideration of the whole scheme of that taxation. A reduction to 15s. per horse-power on vehicles which are included in the horse-power class would be no more than just, and, in view of the fact that the railway groups are seeking powers to run upon the roads, the increase in taxation of goods vehicles and motor hackneys imposed in the interests of the railways should be cancelled.
This increase, against which a strenuous fight was made on the consideration of the Budget of 1926, has had its effect in 1927, for the natural growth in the number of goods vehicles was checked, and 4,394 fewer hackney •vehicles were licensed during the year. The average receipt in respect of a whole-year licence for a goods vehicle was £21 Os. 6d. in 1926 and £28 11s. 6d. in 1927; for a hackney vehicle £33 18s. 6d. in 1926 and £46 19s. in 1927. This represents a substantial handicap to the owner of a fleet of vehicles—a handicap that must now be removed, and particularly if competition from well-equipped railway rivals be allowed.
The Progress of the Pneumatic Tyke.
IN the face of much criticism we have for a long time past advocated the more extensive employment of pneumatic-tyre equipment, not only on small goods and passenger vehicles, but on those of large capacity, and, fortunately, early failures with such equipment did not dishearten users, for the tyre manufacturers, with admirable enterprise, tackled the problem of the large pneumatic with such energy and perseverance that their products are now achieving almost unlookedfor success. This has been proved by the general approval and the high opinions expressed regarding pneumatic tyres by a number of prominent users, selected at random, from whom we recently obtained reports.
The average mileage obtained has exceeded the most sanguine expectations. Reasonable overloading has caused no failures and no cases of accident that could be ascribed to bursts have been brought to our notice. Occasional punctures are unavoidable, but even in this respect the average mileage between such incidents, In the cases to which we refer, have been remarkable, being something over 30,000 per vehicle, so that if the liability to puncture were the same for each tyre something between 120.000 and 180,000 miles per tyre would be obtained. This means that manly tyres, do not experience a single puncture throughout their lives.
These results apply, of course, to passenger vehicles only, where, admittedly, the work 14volved is perhaps not so arduous as is found in the case of vehicles utilized for the transport Of goods, but.they form a good basis upon which to draw conclusions, and we have no doubt that it will not be very long before all, except the very heaviest of goods vehicles, will be similarly equipped, with corresponding benefits to the road. the vehicle and the load.