OPINIONS and QUERIES
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Oil-engine Interest in U.S.A.
The Editor, THE CoitmEactAL MOTOR.
[4026] Sir,—I wish to take this opportunity of telling you. how much I like your paper, also your manual " Compression-ignition Engines for Road Vehicles," of which I have both editions.
The subject of such engines interests me greatly, and I have been able to follow their development and learn much about their advantages through your publications. It is my firm belief that the future of the internal-combustion engine lies in this direction, because its greater thermal efficiency alone should be sufficient for •, its advance. As a power plant for mechanized military units it should be ideal, and I advance its merits at
every opportunity: • • • .
' In this country Mr. Cummins has been pushing the development of his high-speed oil engine, and has made Many demonstrations of its merits by carrying out long, fast, cross-country runs, the results of which answer his critics better than reams of arguments. Because of these tests, the demand for the Cummins engine has increased, and now several fleet owners and truck manufacturers are offering vehicles for sale in which this make of motor can be fitted at option,.
• New legislature and competitive pressure are forcing truck users and makers to decrease the cost per tonmile of of vehicle operation.
Your Tables of Operating Costs, when converted into percentages, show that proportional savings can be made by the use of oil engines without impairing service or reducing ton-miles.
I eagerly await future copies of your publications. H. W. BEARD, St.Sgt.Q.M.C., Holabird, Quartermaster's Depot.
Baltimore, U.S.A.
Loss of Oil Pressure on a Morris-Commercial Engine.
The Editor, THE COMMERCIAL MOTOR,.
[4027] Sir,—We were much interested in the letter from E. W. Pile in your issue of March 17, regarding the mysterious" loss of oil pressure which he experiences in his Morris-Commercial Leader engine after a reassembly.
This can be easily explained when one remembers that the engine is fitted with a special device for stopping the oil escaping in the event of a fracture of the small pipe up to the oil-pressure gauge. It consists of a ball valve which, due to its weight, normally remains open, but which is forced against its seat by an flow of oil past it, such as might occur when the pipe breaks. Evidently what is happening in the engine in question is that the pipe to the gauge is full of air and not oil; consequently when the pressure comes from the pump this air is compressed easily, and the on flows by the ball sufficiently fast to push it on to its seat. The remedy is simple. Make sure that the ball Is at the bottom end of its barrel by unscrewing the oilgauge pipe and using a thin piece of wire down the stop cock which is placed at the top. Shut of the cock and couple up the gauge pipe again. Then start the engine, and after a few seconds' running open the stop cock very slightly so as to allow whatever oil goes into the gauge pipe to do so slowly. When the gauge reads the necessary pressure, open the tap fully and then no further trouble will be experienced.
We feel sure that this will get your correspondent out of his difficulty.
Moan's COMMERCIAL CARS, LTD, Birmingham.
Municipal User's Views on Oil Engines.
The Editor, THE COMMERCIAL Murcia.
[4028] Sir,—I have read with a great deal of interest the expressions of various municipal managers on their oil-engined vehicles, but am surprised to find that no expressions are apparently available from the two largest users—Manchester, with close on 100 vehicles; and Rochdale, with about 45.
In no case does the fleet of such vehicles controlled by your contributors exceed six, and, whilst an intensive system of costs may be kept on a small fleet, it would, in my opinion, have done a great deal more towards the furtherance of the adoption of oil units if the views of the controllers of larger fleets had been sought. F. B. LEE. Manchester.
[We quite agree as to the value of expressions of opinion from the transport managers of Manchester and Rochdale. We asked for these but received no reply.—ED.] The Editor, THE COMMERCIAL MOTOR.
[40291 Sir,--In your special Municipal Numberof March 17, on page 164, you publish an article, " Municipal Experiences with Oil-engined Buses." It would appear to be both fair and opportune while on this subject to mention that the pioneer engine for bus service
• in this country was the famous Mercedes-Benz engine which was fitted to a Karrier chassis and put into service on March 9, 1930—i.e., just over three years ago. It may interest your readers to know that this bus is still going as strongly as ever on the Sheffield-Doncaster route, and has done an enormous mileage, probably well over 120,000.
The first oil-engined bus to run in Manchester —a Crossley fitted with a Gardner 6L2 engine—is also still going well, and has done an enormous mileage, with very low maintenance costs. Thirdly, the Leeds doubledecker, with the Gardner 6LW engine, which has about completed 50,000 miles of hard town work, and is in perfect order, is doing somewhere near 1,000 miles weekly.
_ These three pioneers. seem to me to deserve mention, more especially '..as none -;of the newcomers has had tinie to do anything like such a mileage.
It is gratifying to see that at long last most of the principal --municipalities are either trying out oil vehicles or are arranging to do so, and there is no doubt that the number of such buses on the road will rapidly increase. We shall also see, from this new phase, the "sifting of the wheat from the chaff," because, as distinct from the goods haulage industry, the engines will bevery touch "in the limelight " and under constant 'observation not only by the corporation staffs, but by the public. All of them, of course, will show economy , in fuel costs over petrol, but this will vary constantly according to makes. The real test will be the maintenince costs and reliability over the next two or three years' running, and we shall surely see some interest ing results. W. H. GODDARD. Leeds.
Brake Efficiency on Public-service Vehicles— the Need for a Definite Guide.
Tire Editor, TEE COMMERCIAL MOTOR.
[4030] Sir,—Iu connection with inquiries now being made into the causes of accidents OR the road, we think the enclosed report will be of interest.—[We append a r6sume of this.—ED.]
In the classification of the causes of accidents, a point which, in our opinion, is of great importance, is usually overlooked. We refer to the fact that whilst the primary cause of an accident is correctly classified under its appropriate heading, the analysis fails to indicate the secondary action by which the accident could have been prevented.
For instance, a cause to which a large number of accidents is attributed is "failure of the human element." Now, in this class of accident the fault of the human element at first produces only an emergency, which may or may not develop into an •accident. The secondary action which will avoid the emergency developing into an accident is, in 90 per cent. of eases, the prompt use of efficient brakes. We contend, therefore, that braking efficiency is of much greater importance than would be judged from a study of accident statistics.
The report throws considerable light on the attitude of those responsible for the condition of the brakes on the majority of public-service vehicles running in this _country. The variations in importance attached to braking by the different concerns seems to us to point, very clearly, to the need for a definite guide from the Minister of Transport as to what degree of braking efficiency would be considered as sufficient to meet legal
requirements. E. M. WEsTort, Southampton. For Tapley and Co.
[The report referred to in this letter is too long to reproduce in full. It concerns figures given by companies and corporations operating the largest coach and bus services in
• the country. Of 41 -which replied to an inquiry, 22 intimated definitely that the braking efficiency of their vehicles is not maintained to any particular degree . of efficiency, whilst 19 gave the minimum degree of efficiency at which Tr vehicle is allowed on the road. In some cases the figures given were those stipulated by the Traffic Commissioners. These vary from 50 degrees to 26 degrees in different localities, and as the higher is required in a district where the roads are mainly level, no guide is thus given as to what braking efficiency would comply with legal requirements. If the figures which refer to four-wheel brakes are abstracted, the degree of efficiency which can be maintained as a minimum on the classes of public-service vehicle at present in use averages, for four-wheel brakes 50 per cent., and for two-wheel brakes 30 per cent., the equivalent stopping distances from 20 m.p.h. being 26.8 ft. and 44.7 ft. respectively. Of the 19 definite figures, the lowest efficiency demanded for the foot brake was 26, and the highest 60, whilst for the hand brake the lowest was 15 and the highest 50. One concern quoted figures of over 100 per cent., and, therefore, too high to be practicable.—En.) B30 "The Commercial Motor" in New Zealand.
The Editor, THE COMMERCIAL MOTOR, [4031] Sir,—As a regular subscriber to your publication, I must say how valuable I find the information and advice contained therein. I am traffic manager of a local bus service here, and would appreciate a copy of your Tables of Operating Costs, also any other specialized information likely to be of interest.
The articles by " S.T.R." are particularly useful, and I have often wished we could have a few more articles on the same lines dealing with practical problems met with in the bus business.
Out here we are closely following the progress of the oil engine, and hope, in the future, to see some practical demonstration of the Gardner.
In conclusion, I must congratulate you on your efforts on behalf of the industry generally, and on the verylue
publication produced for it. F. J. PATTEN. Napier, New Zealand.
Preventing Damage to Van Doors.
The Editor, TETE COMMERCIAL MOTOR.
[4032] Sir,—Among my vehicles I have two light 15-cwt. vans, and I have had some considerable trouble with the rear doors, which are double. As a reader of your paper, I would be glad of your advice. The doors of these vans are inclined to fly open with the wind, when they are unfastened, causing damage to the hinges and to the door frames.
I have tried leather straps, chains and hooks, but none of them appears to be any good. Can you advise me whether there is any attachment made, which opens with the doors and keeps them rigid in any position?
You will realize that unless the attachment is autoMatic, drivers of vans do not take the trouble to place any attachment in position, and J have come to the conclusion that it must be automatic.
Dolgelley. H. MILES WInnt.akts.
[We suggest that a strong door stop could be made of two
pieces of fiat mild steel about in. by Ir in., riveted together, and at the outer ends, screwed to the top of the door and body respectively. This kind of door stop is used for private cars. If the door is to be kept rigid in any position, then we would advise a knuckle joint, so as to produce more friction, This knuckle joint would be similar to, but of lighter construction than, the outside joint of the folding head of a taxicab or landaulet. A local coai_dabuildetwould fit these for you. Door trouble is eliminated if a roller shutter be fitted instead.—En.] Payment Refused for Alleged Inefficient Work: The Editor, THE COMMERCIAL MOTOR.
[4033] Sir,—Would you kindly advise me on the following matter. In November, 1931, I gave an order for a new Bedford vehicle to a well-known agent. Certain additions and alterations were to be carried out on and in the body.
I agreed to pay the amount of £20 for the alterations, but when the vehicle was delivered only part of the work was carried out. I refused to pay the whole £20, but paid £7 13s. 8d. in all. The agent has now summoned me for the balance, tile summons being issued by the King's Bench Division.
As I canna, understand the usual routine of this summons I would appreciate any information you can
give me. WORRIED.
Newbury. •
[If, as we assume, you wish to contest the claim, we advise you to consult a local solicitor at once, and instruct him to enter an appearance on your behalf. He will then give formal notice to the court, and to • the company's solicitors of your intention to defend. He will also • explain the steps which have to be taken to put your case before the court. If you do nothing the company will be entitled to sign judgment against you without further notice and to distrain upon your goods for the amount of the claim and costs, including the costs • of the judgment—En.]