OPINIONS and QUERIES
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Support the Road.
The Editor, TETE COMMERCIAL MOTOR.
[3972] Sir,—Much could be done to counteract the disastrous effects of the publication of the Salter Report by executives a all concerned in the commercial-vehicle trade giving instructions to their buying departments to insist on the road delivery of all supplies ordered.
Order forms should be overprinted in red stipulating road delivery as a condition of the order.
If suppliers will not meet this request, DO difficulty will be found to-day in eliminating them.
A concerted effort in this direction would do much to improve the conditions of the haulage industry and encourage the demand for vehicles.
Formerly some .hundreds of "tons of steel were annually delivered by rail to our associated company at Uxbridge. This traffic is how all being carried by road.
Orders from the railway companies rare usually taken at very cut prices and manufacturers should realize that the actual supplying of these purchasers is only still further weakening their position.
The day when anyone could run with the hare arld hunt with the hounds has gone by.
The views of trade or daily journals in which advertisement space is to be taken should similarly first be carefully investigated. It is definitely bad business to spend money which is being used on propaganda to damage the advertisers' business.
Support those who support us should be the policy for all in the trade.
H. R. HOOD BARR% Managing Director, G. Scammell and Nephew, Ltd., Carrimore Six Wheelers, Ltd., Mann Steam and Motor Wagon Co., Ltd., Steel Barrel Co. (of Uxbridge), Ltd.
London, E.1.
Direct-injection v. Pre-combustion-chamber Engines.
• The Editor, THE COMMERCIAL MOTOR.
[3973] Sir,—As Mr. Tangye is evidently under a grave misapprehension about the compression ratios of pre-chamber engines, may I quote from your own valuable book, "Compression Ignition Engines for Road Vehicles "-2nd edition, which is up to date and gives the compression ratios of all the known pre-chamber engines in the world—as follow :—A.E.C., 164; Armstrong Saurer, 15.5-1; Aster, 15.64; Berliet, 15-1; Bussing, 17-1; Deutz, 18-1; Dorman, 15.5-1; McLaren, 15-1; Mercedes Benz, 14,7-1; Wiseman, 15.2-1; and then Tangye, 14.2-1. The average compression ratio is 15.6-1.
The average of a similar number of direct-injection engines is 14.52-1, of which the lowest is the Gardner with a 13-1 ratio, this latter being, I believe, the lowest in the world.
Every pre-chamber engine so far produced has needed —or at least has been fitted with—electric heater plugs, including the Tangye engine. Why are these required? . The answer is too well known—on account of lost heat, the same thing requiring the need of higher compression ratios, as shown above.
Mr. Ricardo has, in his various lectures, stated that this loss is of the order of 15 per cent. to 20 per cent., and this is found to correspond almost exactly with actual road results.
The total number of makes of heavy oil engine, as recorded in your book, is 29. Out of this total no fewer than 58.2 per cent, are of the direct-injection type, and 27.5 per cent. are of pre-chamber design Surely this is very significant and convincing? The Tangye engine of 9.2-litre capacity develops 130 b.h.p. at 2,000 r.p.m. The Gardner OLW, with 8.4 litres, develops 102 b.h.p. at 1,700 r.p.m. There is not much doubt which is the better performance, after taking speeds and capacities into consideration. W. H. GODDARD, Leeds.
Instruction Books on Commercial Bodywork. The Editor, THE COMMERCIAL MOTOR.
[3974] Sir,—I desire to purchase a good text-hook on th4 principles of commercial bodybuilding, and wonder if you could possibly help me by recommending a useful book of this nature. Although I have a certain amount of practical knowledge on this subject, I should like to study the theory, and it will not matter how simple the books, as I wish to start from the beginning. I would prefer a book that also includes descriptions, weights and relative values of different grades of timber used in the construction of commercial bodies, if such a book be obtainable.
I have lately seen a leaflet describing a new publication, entitled "Private and Commercial Motor Body Building," by H. J. Butler. However, in the first place am not interested in private motors, so far as construction is concerned, also this book devotes a lot of space to such matters as costing, repairs, trimming, etc., and these subjects are out of my sphere.
Perhaps I am "striving for the unattainable," but I am naturally desirous of obtaWing the most for my money, and if you could give me any advice in this direction, it would be very much appreciated, and I thank you in anticipation of your usual kind CH operation. G. K. GODDARD. Nottingham.
[There is no book which deals exclusively with the theory of commercial body building, but you will .find Mr. Butler's book useful, because there is a long chapter on timber, and there is as much information on commercial as on private bodywork. The same author's hook " Motor Bodywork," published in 1924, has over 200 pages devoted to
the commercial side of the industry. This is, of course, out of date so far as many 'details of exterior design are concerned, but the elementary principles are still the same. For handbooks exclusively devoted to timberyou will find much information in the \publications of the Department of Scientific and Industrial Research, which may be obtained from H.M. Stationery Office, such as:— " The Uses of Home-grown Timbers" (1s.), "British Hardwoods ", '(5s.) ; "The Principles of Kiln Seasoning of Timber" (9d.), "Dry Rot in Wood" (is. 6d.), "Mechanical and Physical Properties of . Timbers" (2s.), "The Principles of Woodworking" (2s. 6d.) and "Rim" (3s. 6d.).—En.]
Buying British-built and British-owned.
The Editor, THE COMMERCIAL MOTOR.
[3975] Sir,—I am glad to read in The Commercial Motor what Mr. George Mitcheson has to say about the refusal by local authorities of contracts to companies not under British control. It is my own opinion, and that of very many others, that we are justified in considering whether we should continue to support American industry, in particular, both by buying goods imported from the States and by accepting as "British made" the products of American organizations now based in this country.
Although they may be described as "Made in Britain," goods of American raw material, produced by Yankee methods and providing profits for the United States, are clearly not British goods.
The consumer should remember that distinction.
London, N.W. 3. O'D. SINCLAIR (Lt.-Col.).
[It should be a matter for the trade organization concerned to decide what can be truly termed British made, and consideration should certainly be given to the origin of the raw materials employed. Provided, however, that a high percentage of these materMls is produced here, and that the labeur is all British, thus providing employment both before and during production, the question of the capital utilized and the ultimate destination of the profits can hardly be considered as a bar sinister.—En4 Oil-engine Timing and Fuel.
The Editor, THE COMMERCIAL MOTOR.
[3976] Sir,—I have read with much interest your book " Compression-ignition Engines" and have gained from it much useful information regarding this type of engine. There are, however, a few points on which I am not quite clear. First, in the one ease where valve timings are mentioned, I notice that the exhaust valve is set to close 20 degrees before top dead centre; I cannot quite see why there should be such a difference from the timing of petrol-engine valves, where the exhaust closes after top dead centre. Is this the usual timing for these engines, and, if so, what is the explanation?
Another point is concerning the fuel used. All the fuels mentioned are of mineral origin, and I would be interested to know whether there is any fuel of vegetable origin, similar to the alcohol fuels sometimes used in electric-ignition engines, or whether such a fuel could be used. We must always bear in mind the fact that petroleum is a mineral deposit, and as such supplies are liable to become exhausted, or at least so scarce as to raise the price unduly, and a vegetable product, since it is constantly being replenished, would certainly give stable prices. Incidentally, such a fuel could be completely manufactured within the British Empire, and we should thus be independent of supplies from foreign sources. It seems a great pity that alcohol has not been more extensively used in electricIgnition engines, in view of the much improved perform
ance it gives. F. W. PITTUCIC. Birmingham.
[In certain cases, owing to the inherently cool running of oil engines, there is a tendency for the pistons to work at comparatively low temperatures, and for the injected oil to reach the cylinder walls in liquid form, setting up undesired lubricating-oil dilution ; this occurs particularly B30
when injection is horizontal, or almost so, as in the engine to which you refer. To obviate this, one plan is to close the exhaust valve early, so as to leave a strata of hot gag immediately above the piston; this tends to " vaporize " the next quantity of oil injected if it approaches the piston before burning occurs. Naturally, some of the heat from the strata is lost to the incoming air but a portion remains as a safety "blanket." For work in cold climates this scheme offers advantages. At present mineral oils are used exclusively, as they contain the required -chemical components, merely requiring refining. Vegetable oils could doubtless be manufactured, but the addition of " accelerators," to make up for natural deficiencies, increases the cost to such an extent as to be commercially impracticable. In time, research will, no doubt, enable vegetable-base fuels to be evolved; at the moment mineral-base fuels are not CVO]] the known quantities to which we are normally accustomed in the case of petrols.—En.] When is a Lift Van Part of a Vehicle ?
The Editor, THE COMMERCIAL AIDTOR.
[3977] Sir,---As a regular reader of your paper, I should esteem it a great favour if you could offer me your advice on the following matter :—There is a question arisen here with respect to the amount of licence payable on my various petrol motors, which are used for general haulage work. When the motors (which are all of the platform-body type) were first licensed they were weighed as a complete unit. I am called upon on two or three occasions per week to carry furniture lift vans for a local removal contractor, and the authorities NW say that I am liable for additional tax, as they cOnsider the lift van part and parcel of the motor body and say that it should be included in the unladen weight. I, however, contend that it is a part of my load, as the vans are lifted off immediately the furniture has been delivered and the motor gets back to the removal contractor's depot.
I have, along with ether haulage contractors, been carrying furniture vans from time to time in this manner for many years, and I know there are other haulage contractors who have, and are, doing the same thing; but, so far as I know, no one except myself has been approached by the authorities with a warning that I am not paying the proper tax.
The chief clerk in the motor licence department has told me that they intend to charge me this additional tax for the past 12 months, which covers the time that I have been actually carrying for the removal contractor previously mentioned.
Will you kindly inform me, so far as possible, of my
exact position in this matter? REMOVALS. Oldham.
[It has been pointed out by the High Court that the question of whether a, motor vehicle with a lift body is one complete vehicle, or whether it consists of a motor vehicle with a load, is a question of fact which has to be determined by the magistrates before whom any proceed: ings are brought.
We consider that the argument which should be advanced in your case in favour of the view that the vehicle alone should be weighed and not the lift body, is that the lift body is not your own, but is simply the packing case in which the customer places the goods for transport, it being immaterial whether the goods are put into a large packing ease or into a lift body. This procedure is quite different from that in which the owner of the vehicle also owns the lift body which has been made expressly for use on the vehicle, and which really transforms the vehicle from an uncovered to a covered one.
As the question is one of fact, it is not possible to get any ruling from the High Court which assists in deciding these cases. It is quite possible that if the question of the same vehicle came before a number of different benches of magistrates half of them would decide one way and the other half the other way. The only ease in which an appeal can usefully be made to the High Court is where it can be shown that there was no evidence upon which the magistrates could have found that the lift body formed part of the vehicle. In a ease where the duty has been paid at too mew a rate, the authorities are entitled to recover the duty for the previous year.—En.]