Opinions from Others.
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The Editor invitee correspondence on all subjects connected with the use of commercial motors. Letters one side of the paper only, and tyPe-written by preference. The right of abbreviation is reserved, and no
should be on responsibility
for the views expressed is accepted.
Spring Wheels and Flexible Hubs.
The Editor, 6` THE COMMERCIAL MOTOR."
[922j In spite of the fact that a very large number of patents has been granted during the last so years for spring wheels of one form or another, a thoroughlysuccessful spring wheel, which will stand the wear and tear of everyday use on commercial motors, is, like perpetual motion, an unrealised dream. Most of the devices patented, after about six months labour on the part of their inventors, and the expenditure of a large amount of cash, have been discarded as absolutely worthless. The principal difficulties in the way of making a spring wheel may briefly be put under three heads : (I) limitation of space for springs ; (2) weight ; and (3) durability.
Examining the wheel under each of these heads In turn, it will be admitted that : (t) as the average size of wheels on commercial motors is only about 36 inches in diameter, and the largest not more than 42 inches in diameter, there is only some eight or nine inches of spoke between the hub and the felloe (and even less on rubber-tired wheels), and, as the complexity and direction of strains and movement render it imperative that a number of springs be used in each wheel, this valuable space is insufficient to accommodate springs and brakes of ample strength and size to be of practical use—if made sufficiently strong to bear the heavy stresses, and to stand the rough shocks imposed upon them, they lack the elasticity which they were intended to possess ; (2) everyone interested in the commercial motor industry knows the importance of the weight question, and, unfortunately, the additional weight incurred by spring wheels is not justified by the results of past experience ; (3) the moving parts of most spring wheels are so numerous, and the parts so difficult to protect from mud and rain, that very rapid wear takes place, and they soon become " rattletraps."
Attempts have been made, from time to time, to em. ploy flexible spokes in the construction of spring wheels, thus doing away with the necessity for loose springs and a large number of parts, but with poor results, as, owing to the severe strain
and continual bending, the metal of which the spokes are made soon becomes crystallised, and fracture takes place. In the opinion of the writer, the best and most practicable attempt to minimise the road shocks, and to lessen the jars transmitted by the axle of wheels travelling over rough roads and pavements, is Smith's flexible hub, although this can scarcely be called a spring wheel. The Smith hub, as no doubt many readers of "Tan COMMERCIAL MOTOR" are aware, is really a rubber-cushioned wheel, in the construction of which the flange bolts pass through blocks or bobbins. The weakness in the design of this hub is that rapid wear is sure to take place, owing to grit and dust working in between the hub and the flanges. The use of grease or oil lubricants between the rubbing surfaces would lead to deterioration of the rubber. As the movement is very small, probably not more than half an inch, I should say the best way to overcome this difficulty would be to use a thick rubber washer or flange, say, some one inch thick, or thereabouts, on each side of the wall be
tween the iron flanges, and if the faces of the flanges were roughened, so as to grip the.rubber and to prevent " fridging," and the bolts not screwed up too tightly, the rubber washers or flanges would stretch, pull from side to side, and follow the inside rubbers without any relative surface motion taking place, and, consequently, no water or grit could find its way between the faces. Weight and cost have to be considered in adopting a wheel of this kind, and for these two reasons I should never think of using a Smith hub in connection with a rubber-tired vehicle, as the rubber tire itself eliminates the jars, and reduces the shocks that otherwise would b2 transmitted to the axles and springs, but on steeltired vehicles the resilient or flexible hub would undoubtedly relieve the springs and axles, and indeed all parts of the vehicle from the harsh shocks and jars, and it is therefore, well worth the consideration of users of steel-tired vehicles. Against the extra cost of the wheels the user has to put the saving in wear and tear of the machine, and particularly the breakage•of springs and axles, in addition to the smoother and quieter running which such wheels would give.—Yours faithfully,
" OBSERVER."
The War Department Trials.
The Editor, "THE COMMERCIAL MOTOR."
[923] Sir :—The views expressed by " User" in the article which appeared in your issue of the 1st instant will greatly amuse those who followed any part of the trials, but the reader who did not have opportunities to watch the performances of the machines might be misled into the belief that" No. To " has been somewhat harshly treated both by the judges and the Press; the letter from its makers, which you publish in this week's issue, is well calculated to increase that belief,
If " User" knows anything about heavy commercial motors, he must admit that the first cost should not be the only consideration when purchasing a machine. By reason of the necessity for frequent and extensive repairs and replacements, a machine whose first cost is, say,
may lead to more outlay for capital and mainten
ance in the first year than one which costs, say, half as much again. Then, further, the delays due to the failure of parts would lead to heavy losses. Although No. to " was completely outclassed, in addition to its hauling a load about 50 per cent, greater than its normal capacity, the owners and "drivers " put up a plucky fight, greatly to the inconvenience of some of the trials officials, who were kept out of bed until well into the day following each of its " jaunts " into the country. Taking the cost of depot repairs and time on the road into account, I should say the cost per ton-mile for " No. to " greatly exceeded that of either of the other competing machines, although I only have rny own observations to guide me in making this estimate. Further, for most of the running time, five men were in attendance on " No. to," not including a responsible representative of the builder. 1 think that fact alone disproves " User's " statement that the machine is " simple to drive."
Mr. Broom, I find, sends his letter in reply to mine of the 25th of March, and he states that the consumption for his engine was 15 per cent. better than for " No. 4," in spite of three conditions which he names, In the first place, I find that Mr. Broom is wrong in his statement of percentage. Based on the figures given in the table which you published in your issue of the t8th March, the average rate of consumption for " No. 4 " was 0.9083 lb, of fuel per net-ton-mile, as against No. to's " 0.9583. In other words, the rate of consumption on " No. to was 5,1, per cent. higher than on " No. 4."
So far as the conditions (i) and (2) mentioned by Mr. Broom are concerned, I would ask him did not the other machines work under them too? And, regarding his plea for sympathy because the wheels of his tractor did not track with those of his trailer, and because, in consequence, his machine and load were compelled to make four ruts instead of two, I would point out to him that the near-side driving wheel of " No. 4 " neither tracked with the near-side leader nor with the trailer wheels; consequently, five ruts were rolled.—Yours, etc.,
Aldershot. H. Put.i.F.N.
8th April, 1909.
Users Experiences (No. X).
The Editor, " Tiff; COMMERCIAL MOTOR."
[924] Sir :—Referring to my two previous letters on the subject of " Fines " and " Local Police Court Extremes," I think it might be well to emphasise the fact that they were not intended to convey the impression that there exists a general persecution of motor-vehicle owners by the police and magistrates, but rather to call attention to the exceptional cases which require special attention.
We recently assisted in the removal of a " hunt "; the order was booked by telephone, and, from the very incomplete instructions, it seemed that harness, saddlery, and puppies in cases would form the freight, so I sent out a wagon and trailer with a couple of tarpaulin sheets. About mid-day, I received a message from my driver for an extra sheet to be sent out to him, and a request that I should come and inspect the load when he was passing through the town. It would be difficult to explain my feelings, on catching sight of my man, who was smiling contentedly with a load behind him which must have been at least 8-in feet high on the wagon, and consisting of beds, chairs, mattresses, hoses, pianos, hat boxes, a pianola, a few bird rages, and all the paraphernalia included in a general-removal job, whilst, from his trailer, peeped 28 couples of puppies, all trying to enjoy their first experience of motoring. It was one of the finest feats of loading I had ever witnessed.
I have recently had occasion to listen to some rather caustic remarks from a friend (whose house my wagons constantly pass), on the subject of the vibration set up by motor wagons. I was told that the furniture played most peculiar antics, the pictures assuming a pendulum action, and the tables and chairs skipping like young lambs. I have never been present when the phenomena occurred, but am prepared to accept the statements with a certain amount of reserve. Assuming the facts are correct, my
wagons should be suffering proportionately. Can you suggest anything in the nature of a spring wheel or cushioned hub, Mr. Editor, as the matter seems urgent? —[We prefer to absorb shock at the periphery, by rubber tires, where really necessary.—En.I
There is a decided tendency among motor-carrying businesses to combine, in some degree, and to my mind it is a very excellent suggestion, providing too much is not attempted at once. At the present moment, there are too many small concerns in existence ; either from want of stability, or lack of experience, they offer absurdly low rates, which are quite unworkable and in no way represent the market value of the work performed. I would suggest that at first combination should take the form of a central intelligence bureau in a district, to which the various branches should subscribe. The rubes of first importance would be : (i), an agreement between members not to compete against each other; (2), an arrangement as to minimum rates at which certain classes of traffic should be carried; and (3), the establishment of a central office in a distinct for enquiries. There are plenty of other points in which co-operation could be effectively introduced, but they could he better dealt with after the principle of co-operation had been established. The main object of any such association should be to obtain the advantages of co-operation without interference with the individuality of the concerns co-operated. I believe 44 THE COMMERCIAL MOTOR is in favour of some such scheme as I have outlined, and would suggest that it would be favourably placed for assisting in the preliminary stages.—fWe shall be happy to have any confidential suggestions from hauliers.—ED.] I should be interested to know if any of your readers have tried metallic packing in their steam wagons, and if so with what results. I. am at present considering the question of trying some, but am rather doubtful about the effect it may have on the rods in case of picking up bad water.
The particulars of the week's work are :—earnings, ..47; tonnage, 128; mileage, 688; percentage of work done, go; coke used, 6 tons Jo cwt. ; oil (gear), io gallons; and oil (cylinder), 5 gallons.—Yours, etc., " MOTOR-WACON CARRIER."
"Loud and Continuous" Warning.
The Editpr, "THE COMMERCIAL MOTOR."
[925] Sir :—Having perused your excellent leader in your number of April 8th upon the subject of the new regulations, which have been apparently purposely allowed to leak out, there are two points to which, as a member of the travelling public, I should like to draw attention.
I.—The most unreasonable proposal that every motorcab or motorbus should, when the vehicle reaches a certain speed, emit a loud and continuous sound is one of the attempts often enough proposed to prevent the motor vehicle from getting along in traffic any faster than the horse-drawn vehicle. I desire to emphasise the fact that if you restrict the speed of motor vehicles in the way proposed, they will be unable to pass the horse vehicles, and will, therefore, be no quicker, and consequently the very object of their existence will he gone. When I take a motoreab, I take it firstly to get to my destination as quickly as possible, and secondly 1 take it in preference to the horse-drawnvehicle precisely because it is faster.
2.—All motorcabs are taxicabs, and, as is well-known, the taximeters register by time as well -as by speed. If the taxicab is to be restricted in its speed to that of the horse-drawn vehicle, the cost will be increased from 30 to so per cent., instead' of being, as they frequently are, cheaper as well as more expeditious than the horse-drawn vehicle, they will in all cases be more expensive, and being, under the proposed regulations, as slow as horsedrawn vehicles, all those inducements which at present cause the public to patronise motorcabs to the enormous extent which they do will be gone, and with them will disappear also the motorcabs.—Yours, etc., London. " TRAVELLER."