IN YOUR OPINION
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Reverse Gear Pedal?
MAY I, as a practical operator, join the discussion on commercial vehicle brakes (The Commercial Motor, last week). I am going to jump right in and say I am shocked to think that a group of technical experts should accept the principle that retardation should be progressive until the ultimate is reached where the wheels are locked.
I should like to see the retardation action progress until, in extreme cases, the wheels actually revolved in the opposite direction to normal travel. May I illustrate what
mean in a practical way? Those of us who can remember bad( to the T pattern Ford days will recall that when we had reached the stage where we had burned out our normal footbralce, we relied on the reverse gear pedal to retard our forward motion. Under extreme circumstances, such as on icy roads, it was possible to get the rear wheels to revolve in the opposite direction whilst still travelling in a fo-rward direction.
Our technical friends touched on some of the problems of articulated operation and in particular that of jackknifing. Now, if the principle of a turbine could be introduced to the semi-trailer wheels it would, in my opinion, solve this problem. The retarding effect of the turbine being driven against the direction of rotation would be terrific. I am, of course, thinking of emergency stop conditions in the main when I speak of the rear wheels being made to revolve in the reverse direction.
Think of the benefits which would accrue from this method of braking—no brake fade, virtually no effort on the part of the driver, no wearing parts at the brake end of the system, reasonably simple and I would think not very expensive. It might even be possible to use the thrust for forward motion as well.
South Benfleet, Essex. R. B. BRITTAIN, Managing Director, Essex Carriers Ltd.
• AFTER reading your very fine article on commercial
vehicle brakes I feel I must reply. To John Alden I would say yes, his vehicles have the best brakes of the quantity built trucks but these are far from being trouble • free. Although he has an equal front/rear ratio, the rear brake linings are worn out when the fronts are barely touched; we don't like this, we prefer good braking with equal wear all round. Oh! That disc handbrake, John. To say the least, please remove it.
Yes John Moon, I am 100 per cent in your support on ,
Artic Braking Problems
the automatic coupling outfit. Our biggest worry is how to keep the brakes on the semi-trailers; it is impossible to get a good balance. When braking with one unit the trailer just hits you in the back then, after you have decided to move off, the trailer decides to stop.
Furthermore, look at the loads some operators can put on this type of coupling with twin-oscillating axle trailers. I know of some operators who gross 24 tons. The sooner we get plating the better and safer for all it will be.
Alresford, Essex. C. MARTIN.
Congratulations?
I HAVE read with considerable interest the article in last 1 week's issue of The Commercial Motor regarding brakes. My first reaction after reading this article was that it was a pity that the people who use the vehicles were not represented on this occasion, and therefore a lot of the discussion had to be of an academic nature. Another point which struck me very forcibly was the fact that no reference was made during the discussion to the braking requirements under the Motor. Vehicles (Construction and Use) Regulations.
Nevertheless, despite these criticisms, I feel that The Commercial Motor is to be congratulated on endeavouring to foster interest in a matter so vital to operators of commercial vehicles.
London, W.C.1. J. T. TURNER,
Chairman, Vehicles Committee, National Road Transport Federation.
More letters on this subject will be published next week.
Lawyers and Licences IN his letter, published last week, Mr. John May, the managing director of Charles Rickards (Tours) Ltd,, makes certain points that cannot go unanswered.
The final paragraph of the article to which he refers (Licensing Casebook, January 25) clearly indicates that the advice to get a lawyer is aimed specifically at the smaller operator. It is he who can least afford the expense and time involved in making an abortive application to the Traffic Commissioners.
Mr. May, in his letter, answers his own criticism when he states that "a competent applicant can often argue the finer traffic points better than a lawyer...," As managing director of one of Britain's oldest p.s.v. operators he
indisputably fails within this category. I should point out, however, that many chairmen of Traffic Commissioners and Licensing Authorities prefer to have lawyers conduct applications before them, although unrepresented applicants receive the same amount of consideration as those represented by a lawyer.
It is possibly true that air licences are not issued, as Mr. May says, to travel agents and tours organizers direct. As an Air Licensing Board spokesman put it to me : "Air operators apply for licences on behalf of travel agents, etc., but there is nothing to stop anybody applying for an air licence if they want to ", and Mr. May may be familiar with the published Report of the Air Transport Licensing Board dated August, 1961, wherein the deputy chairman links tour organizers and air operators together, whose "energy and imagination have made a significant contribution to British civil aviation ". I would argue, though, that applications for air facilities by these people is the vogue.
When Mr. May asserts that "the boot is on Mr. Tilsley's other foot ", that it is in traffic courts and not at the Air Board that one sees "comical processions of all-expenses paid witnesses ", that may well be true. My article in no way suggested otherwise. The article was about traffic courts and not the •A.T.L.B. I do not profess to be well informed about the Air Board, but I would point out that when I described the proceedings before that Board in "Significant Licensing Cases" (July 21, 1961, issue), Mr. May raised no objection to my remarks.
London, E.C.1. NORMAN H. TILSLEY.
How to Find Out?
EFERRING to Mr. May's letter headed "Licences and Lawyers" in which he says that lawyers can be a great help in traffic courts in suitable cases, I would like to know how an applicant can find out whether or not his application is suitable for him to conduct by himself. I cannot imagine him going to a lawyer and being told: This is suitable for you to conduct yourself "!
Croydon, Surrey. " INTERESTED."
Plastics Tank Manufacture AJ E were pleased to note in your issue of February 1 V v the reference to this company's fabrications of Tufplas all-plastics tanks. We were pleased to see the photograph published on page 86, but. would ask you to correct the impression that this tanker was made mainly by the "filament winding process ". The tanks fabricated by this company are of Tufplas construction which is carried out according to the British patents owned by this company. They are very different from glass-fibre-reinforced constructions produced by filament winding. The inner working surface is of completely unplasticized P.V.C. which obviates the great danger of liquid stress on the fibres of a simple glass-fibre construction, and additionally gives very substantial gains in chemical resistance over a wide range, of materials that would attack a resin surface. The tanks are fabricated by a compound process of which only one element is filament winding. In our view, filament winding is not a method which is satisfactory for the total construction of vessels of this type. We would also remark that the construction principle detailed in your article is certainly not accurate so far as this company's production is concerned: the whole vessel is made in one piece including the domed ends which are, therefore, an integral part of the structure. We do not agree with the method of manufacture where tank ends are moulded into place after the shell has been fabricated and cured. It is also unwise to state that apertures for
azt6 manholes, etc., can be cut into a finished tank without weakening it. This is only so if special provision has been made before the cut is carried out for additional local strengthening at the points of aperture.
All the road transport tanks made by Tough Plastics incorporate, as part of their structure, the rigid polyurethane firm layer mentioned as an insulation.
In your article you say that "Plastics tanks have been made in small quantities in a number of countries since the War, mainly for food products such as wine and milk, and generally in small numbers ". This company has fabricated many hundreds of tanks from 50 gallons to 10,000 gallons capacity—many of them by the hand lay-up process—and no sign of structural weakness has been observed.
Culcheth, Lancs. P. W. MICHELSON, Managing Director, Tough Plastics Ltd.
Transporting Latex WE were interested to read the very useful tables pub" lished in The Commercial Motor of February 1.
The tables illustrate the provisions necessary for handling certain liquids in bulk which we find extremely useful, but we have one criticism to make regarding your recommendations for handling latex. You do not state the type of latex in your tables, but we have been concerned for many years with the handling of natural rubber latex and the distribution of latex to consumers throughout the U.K. We notice that according to your recommendations you mention certain tanks and fittings as being suitable for the handling of this material. However, we must draw your attention to the fact that rubber latex and certain types of synthetic latex require very careful and special handling. Natural rubber latex is stabilized with certain materials and should the latex come into contact with iron, mild steel, or non-ferrous metals, oxidization would take place. For the carrying of natural rubber latex or synthetic latex we would recommend stainless 'steel tanks or mild steel tanks suitably lined with an epoxy-based resin preparation such as Epicote or Ensicote. A bitumastic solution could be used although this is considered not to be wholly satisfactory. We would also recommend that fittings, delivery pipes, valves, etc., be void of. any form of nonferrous metal and they should be of stainless steel or suitably lined.
We also notice that you recommend elliptical or cylin drical tanks for carrying this material. With the elliptical tanks, discharging would have to be completed by centrifugal pump or gear pump. However, we find that this equipment has the effect of disturbing latex and is likely to cause flocculation. It is a common practice for latex to be conveyed in cylindrical tanks pressure-assisted for discharging. Although no heating of latex is required we find it is essential to ensure that it is protected from freezing in extremely cold conditions, and therefore insulated tanks would be necessary during colder weather.
Hull, Yorks. T. MOXON,
Manager, International Bulk Liquids (Storage and Transport) Ltd.
They Did Get Caught WITH reference to The Hawk's "Naughty thought" " in The Commercial Motor dated February 1.
You will appreciate my reluctance to name my company but, just in the general interest of haulage, our tankers did get caught.
RED-FACED TRANSPORT MANAGER,
Somewhere in Arctic Britain.