AT THE HEART OF THE ROAD TRANSPORT INDUSTRY.

Call our Sales Team on 0208 912 2120

OPINIONS FROM OTHERS.

17th March 1925, Page 26
17th March 1925
Page 26
Page 27
Page 26, 17th March 1925 — OPINIONS FROM OTHERS.
Close
Noticed an error?
If you've noticed an error in this article please click here to report it so we can fix it.

Which of the following most accurately describes the problem?

'The Editor invites correspondence on alt subjects conn:cted with the use of commercial motors. Letters should be on one side of the paper only and typewritten by preference. The right of abbreviation is reserved, and no responsibility for views

expressed is accepted.

The Mersey Road Tunnel Project.

The Editor, THE COMMERCIAL MOTOR.

[2,3241 Sir,—The article on the Mersey Tunnel in the issue, of The Commercial Moto,' of March 3rd makes very interesting reading, but you do not state how long it would take before the proposed tunnel could be opened to traffic. In our opinion, with the many disadvantages to which we are accustomed, viz., strikes, etc., it will, we think, take the best part of ten years.

In the meantime, are we to put up with the conditions attaching to the use of the present ferry, that is, wait an hour (if not too late to get across !) get parked like cattle, wait in a queue in the pouring rain until the ticket man is willing to issue tickets (double fare on Sundays), then be made to back off. . the boat with a closed vehicle out of a•crush, crawl behind a heavy slow vehicle up the 'steep floating bridge with a slippery iron plate for one wheel, and timber cross pieces for the other, giving vehicles a real good shake up for a finish?

Surely the increasing traffic and the increasing difficulty of the crossing conditions demand improvement. Until the tunnel is opened, why not borrow . the Seacombe luggage boat for Sundays, which would be far more sensible than crowding on the Birkenhead "old timers" hardly large enough to chase a cat round ? Also, why not alter the floating bridges on each side to take a double row of traffic I—Yours faithfully, THE LIME STREET GARAGES (LIVERPOOL), LTD. Liverpool.

Brakes on Heavy Lorries.

The Editor, THE COMMERCIAL MOTOR.

[2,325l Sir,—I notice in your issue dated March 3rd a letter on the above subject signed "X.U.V," in which he gives an account of an accident he witnessed. In doing so, he allows the reader to infer the brakes were not in good order. Then he proceeds, " The worst offenders seem to me to be found amongst those contractors whose business it is to carry such loads as sand, bricks, gravel, timber, etc." Up to this point I am in entire agreement with him, but from there onward I protest he is entirely wrong.

Building material and bad road conditions near the building sites play havoc with the paintwork and the . men—whether Master or paid driver—quickly realize this, and spend their spare moments greasing, etc., in preference to cleaning paint. Dirty pamtwork mast not be taken to imply lack of attention.

My experience with, a lorry I am driving, seems to lay a good amount of blame on the designer. I drive a 5-tonner of well-known make on timber haulage, doing about 350 miles per week, and I defy any man to pull her up, when fully loaded, on the foot brake ,in an emergency, as might reasonably be expected under the Motor Car Act. The result is that the hand brake comes in for more than its fair share of work and suffers accordingly.

The brake rods are not kinked, the pins and toggles are all well greased and the brake goes on and off perfectly, but it requires -the strength of Hercules to hold a load of five tons on a decent hill. Is it because the foot brake operates directly on the rear wheels? I think so.

After a gruelling hard day it is hardly fair to the driver to have to stand on his brakes in order to stop the lorry in an emergency. I have spoken to 20 or 30 owners and drive m of the same make, and they all experience the same trouble.

(342 I notice that L.G.O.C. buses on route in descend London Road, Forest Hill, in first gear with their engine throttled down. Is this merely " to save their brakes," or is it a weak point•duly recognized? Also, why are Scotland' Yard so keen on the use of hand brakes, considering that both act directly on i the rear wheels? What s the difference, except ill the amount of effort required to operate the brakes easily and quickly in an emergency? No, while admitting that here and there you will find a man who neglects his lorry, I think it is to the designer in the first place that we must look to give us a brake that, properly looked after, will stand up to its work. Then, and only then, can We point to the black sheep who neglects his lorry. This is not an impossibility, as witness the products of the Leyland and Saurer concerns, who turn out chassis not only capable of carrying heavy loads, but fitted with brales capable of stopping heavy loads. I have no interest in either concern except as a driver who appreciates the difference in human effort required to drive various makes of lorries safely, and human effort is a big point to be considered in these days of ever-increasing loads.—Yours faithfully, Sydenham.

Risks in Reboring Cylinders.

The Editor, THE COMMERCIAL MOTOR.

[2,320] Sir,—We are in complete agreement with the reply you sent to your correspondent in connection with cylinder regrinding. When cylinder walls are. worn the bores should be reground, and the risk is infinitesimal, but, if the bores have been scored by loose gudgeon pins, a much superior method of' reconditioning is to have the scores filled in by the Earimar metallurgical process of repairing scored cylinders. This process does not weaken the bores in any way, and the size of the bore is not altered. The existing _pistons are fitted and the repair is guaranteed.—Yours faithfully,

b J. H. OSBORNE, service Manager.

Can Road Crusts Be Strengthened to Carry Modern Traffic ?

The Editor, THE COMMERCIAL MOTOR.

[2,327] Sir,—Without attempting to enter into the controversy as to the respective values of pneumatic and solid tyres and the damage they occasion on road surfaces, I should like, if I may be allowed, to associate myself with the very important question you raise in regard to the "binding up " of surfaces, whether macadam, massed concrete, or other forms used to-day to withstand the abrasive action of vehicular traffic in general.

I notice in particular the views expressed in the last paragraph of the letter which appeared in the issue of The Com,m,ercial Motor for March 3rd over the signature of " C.M.L." He is quite right in bringing out the fundamental principle that no form of road surfacing can be of any value unless it has a solid foundation. A road engineer's most serious, or eoecupa,tion to-day is what economic form of surfacing he can afford to give to a road so that it will stand the traffic it is called upon to carry. This is, unfortunately, the bugbear of the engineer, for the question of cost is one which he has to take into very serious account.

I submit, however, that, with the advent of Modern quick-hardening cements, and, in particular, am minium cements, we have here a means of strengthening road crusts in a way hitherto thought impossible. The ordinary form of granite macadam surfacing has lost favour from one cause only—namely, because, when it is " water-bound," it does not stand the traffic—not so much because the metal itself is incapable of standing the strain, but because that form of water-binding does not hold the stones sufficiently together to prevent " attrition" and to keep it waterproof.

I am, therefore, of the opinion that by the introduction of cement mortar grout composed of clean, sharp sand and quick-maturing cements, " attrition " would be prevented and the road waterproofed economically and made sufficiently resistant to take traffic—solid or pneumatic-tyres—that our rural main roads have to carry to-day.—Yours faithfully,

London. PROGRESSES.

Ambulance Chassis Design.

The Editor, THE COMMERCIAL MOTOR.

[2,3281 Sir,—As one who is connected, from the medical and theoretical points of view, with ambulance design, I should like to make one or two comments on the practical engineering views expressed in the article published in your issue of March 10th, dealing with the M.A.B. ambulance fleet. On reference to the diagram, it will be seen that the driver comes, when seated, just aft of the exact mid-point between the axles, i.e., in the most comfortable position in the vehicle, while the patient, according to whether he rides head first or feet first, rides with the rear axle immediately beneath his pelvis or his abdomen, i.e., in the worst position in the vehicle.

Why must an ambulance have an overall length of some 16/ ft. -to carry a 6-ft. patient? Why must the radiator come immediately over the front axle? With so powerful an engine running with very light demands, large radiators are not necessary, and it seems strange that the first unit which appears on the frame is some 18 ins, from the extreme limit of overhang. Why cannot the engine be brought as far forward as possible and offset somewhat (as is done with the differential casing), so that the driver may at least have his legs alongside the engine, thus cutting down the overall length of the vehicle and, above all, bringing the patient's position forward, so that when he travels head foremost his heed and the whole of his", trunk are well forward of the rear axle. This is the crux of the whole question of ambulance transport but I do not suggest that the solution is a simple one to provide.

It seems to me that the present ambulances are primarily designed for the position of engine and driver, the patient being worked in where he can be fitted in. Why not attack the problem from another view-point and place the patient where he ought to go, leaving the engine and driver to be fitted in where they can be placed? Compare, for example, the layouts of modern omnibuses, S.D. freighters, and the like.—Yours faithfully, MEDIOVS. Purley.

Servo-operated Brakes : Does the Power Increase with Speed ?

The Editor, THE COMMERCIAL MOTOR.

[2329] Sir,—Your correspondent, "F.L.H.," is undoubtedly correct in his contention that the resultant force obtained by the use of a servo drum does not increase with the speed at which that drum is revolving, but would, it. anything, decrease if the speed of the drum were increased beyond certain limits. To end an argument and to satisfy a sceptic, I made a demonstration by ,lapping a cord round a pulley as shown in the accompanying sketch. The weight represents the force applied by the driver, and the pull registered on the spring balance indicates the

resultant force, which in a servo mechanism would mean the power transmitted in the application of the brakes.

No matter at what speed the drum was revolved, the pull on the balance remained constant. Any addition made to the weight showed, of course, a much increased pull on the spring balance.

It is quite possible that, were the speed of the drum increased beyond a certain point, vibration caused through the unevenness of the surface and the trapping of air between the drum and the band might cause the co-efficient to decrease, but at any speed of the drum that would be used for the purpose of a servo brake, this could hardly happen. Perhaps, the idea that such brakes are more powerful when the vehicle is running at a high speed arises from the fact that the driver unconsciously pressed harder on his pedal when running at a high speed than when running slowly. Ii would be interesting to see the experiment tried of having a pedal arranged so that a spring ,pressed the brake on, a catch being fixed to hold it off. The action .of releasing this catch could release a paintbrush (as in .experiments carried out on Bentley oars), which would leave a mark on the ground. This mark would indicate the spot at which the brake was first applied, and the stopping point would indicate the distance which the vehicle travelled before it came to rest. I think this experiment would settle all arguments on the point.—Yours faithfully, London. C. M. L,

Economy in House-refuse Collection. ,

The Editor, THE COMMERCIAL MOTOR.

[2,3301 Sir,—We read with much interest Mr. Monte gomery's letter in the issue of The Commercial Motor for March 3rd in regard to the advantages of the electric vehicle in refuse collecting. In his remarks he is, undoubtecly, correct, so far as the reduction in time wastage in getting going again, after stoppage is concerned. The petrol vehicle is at a, disadvantage in all the work of house-to-house collection, or delivery, in this respect, but ittis equally at a disadvantage with the steam vehicle lithe system adopted in the Stanley cars is followed, because with the latter there will always be an available reserve of steam, just as, with the electric vehicle, there is a reserve of electric power, the car starts instantly on opening the throttle and the maximum power available being instantly at command, the steam vehicle has a much more rapid acceleration than the one driven on petrol.

But the steamer is at no disadvantage in regard to speed in comparison with the petrol vehicle, as is the case with the electric, so that we venture to submit that the steam vehicle meets all the requirements of house-to-house collection work in a much more efficient manner than either of them.

Of course, so far as the steam wagons in use in this country are concerned, they are, none of them, so far as we are aware, built for speed, so that they would probably compare more nearly with the electric vehicle in their characteristics. With the new Stanley commercial vehicle chassis, details of which we hope to submit to you shortly, the advantage of speed is combined with the advantages of instant starting and rapid acceleration, so that it would appear to us that the steam wagons of the future may deal with this problem more efficiently than has hitherto been the case with any form of road vehicle.—Yours faithfully, THE STEAM VEHICLE CORPORATION OF GREAT BRITAIN. Coventry.

Tags

People: H. OSBORNE, Monte
Locations: Coventry, London, LIVERPOOL

comments powered by Disqus