A Synopsis of the Report.
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The Text of the Judges Conclusions, and the Editorial Views Upon Them.
Efficient Organisation.
The Judges, in submitting this report, congratulate the R.A.C. on the thoroughness and excellence of the organisation of the Trials, reflecting as it did great credit on its executive officials. However good this organisation may have been, the success of the Trials was undoubtedly due to the hearty co-operation of the entrants and the cheerful and willing submission to a strict discipline shown by the large staff of Observers, drivers, mechanics, and others engaged in the Trials. The passage of the vehicles through so many towns and villages during a period of six weeks was effected without a word of complaint or criticism either as regards driving or general behaviour.
Local Interest.
The Judges wish to record their appreciation of the reception invariably given by the Mayors and Local Authorities of all the towns and districts visited, and their special thanks to the Police, both officers and constables, for the co-operation and help which they so willingly rendered.
THE JUDGES' CONCLUSIONS.
In submitting the following detailed remarks, the Judges would draw attention to the fact that, although the Trials were the largest and most comprehensive ever held, and possibly may have reached the maximum reasonable limit in extent, the total distance covered was only sufficient to bring out radical faults and weaknesses, and to enable the following general conclusions to be drawn :—
High Opinion of Tractors.
For useful loads exceeding three tons the tractor is the most economical for general haulage. Where speeds are required which are too high for the tractor the internal combustion engined lorry mounted on rubber tires becomes a necessity.
The steam lorry (Class F), although it possesses the disadvantage of large axle weights, can with advantage be employed where high speeds are not required, and where the loads have to be delivered at quays or places where the tractor with its trailer could not be so readily manceuvred.
The first of the above paragraphs may be construed, literally, to the disadvantage of the steam wagon, and we, therefore, reassert our opinion that neither the tractor, nor the internal-combustion-engined lorry mounted on rubber tires, is necessarily more economical than the self-contained motor wagon which carries its load upon its own platform, and has the facultative advantage of hauling a trailer on occasion,
Excessive Speeds Deprecated.
The petrol lorries submitted were capable of speeds on the road which were excessive, and should not be tolerated. A general reduction of gear ratios seems a necessity, and would result in greater economy, inappreciable loss in average speed on the road, and less wear and tear of both road and vehicle. The cost of upkeep increases very rapidly with increase of road speed, and, although the true economic speed has not yet been determined, high maximum road speeds should be avoided as a general rule in commercial vehicles.
Here, again, the statement that a general reduction of gear ratios seems a necessity appears to require qualifying, at least so far as vehicles with two-cylinder engines are concerned. The first word in this conclusion might well have been " some," rather than "the," and we agree that there were several flagrant cases of overdriving. Reliability, Regularity, and Condition at Finish.
The reliability and regularity of running throughout was remarkable. The condition of the majority of the vehicles after the Trials was on the whole satisfactory. The amount of wear on the parts was in many cases inappreciable; but some manufacturers have still much to learn as regards design and the se.ection of material, before they arrive at a vehicle showing low cost of maintenance and durability.
"The Triumph of Rubber."
A striking feature in the Trials was the successful use of india-rubber tires carrying heavy loads up to five tons. About 90 per cent, of the vehicles (excluding tractors) had rubber tires, which gave on the whole remarkably little trouble, notwithstanding the high temperature recorded by the thermometer on several days of the Trial.
Benefits from BaIl-bearings.
It was noted that on more than one occasion, after a rapid run, the hubs of those wheels fitted with ball bearings remained cool, whilst many of those not so fitted were quite warm, and in 0112 or two cases overheated. This points to diminished friction, and, therefore, lessened wear and tear.
On this point, we might remind our readers that the enormous increase of the sales of well-known makes of ball bearings, such as the Hoffmann and D.W.F., has been due to the extended application which the Judges approve, the fitting of ball bearings now tending to become general throughout all parts of a chassis other than the engine. Their use in the motor itself, as in the case of the " Hallford" chassis in the Trials, has been successfully achieved, so far as the crankshaft and camshaft bearings are concerned, by only a few makers.
Road Wheels: Construction and Diameters.
Attention is directed to the projection of the spokes at their felly ends in many of the wood wheels giving short length in the direction of end grain, and consequent weakness. Although aware of the reasons which have induced makers to adopt this shape, they noticed that in several cases cracks were developed giving evidence of faulty design.
Only two types of vehicles were fitted with wheels made entirely of steel, although a third employed a wheel with steel spokes. The cast steel wheel of to-day is practically imperishable if it be shod with rubber tires, but the use of a built-up wooden wheel is an important factor in prolonging the life of a vehicle, and keeping down the repair bill.
It will be noted from an examination of the diagrams*, which are all drawn to the same scale, that the wheels iii Class H (that is, the tractor class) have an average diameter about 30 per cent. greater than those in Classes C, D, and E (that is, the heavier motor wagon classes). The destructive effect on the road is greatly diminished by a small increase in the size of the wheel, and the vehicle itself runs more smoothly. The difficulties connected with weight, cost and material consequent on increase of diameter must be grappled with, and it is recommended that, both for the sake of the vehicles themselves on the one hand, and for the roads on the other, the diameter of wheels should be increased and kept as large as compatible with practical requirements.
Only a portion of these can be reproduced this week.—ED.1 The arguments in favour of greater wheel diameters, qua lessened repairs and reduced rolling resistance on a bad road, are admitted, but it cannot be overlooked that, so far as a lorry is concerned, one of three disadvantages must be corre
spondingly endured : (a) the platform must be reduced in width, so that the wheels may rise above its level ; (h) the level surface of any wide platform must be broken to the extent of boxing in the top of the wheels ; or (e) the height of the platform from the ground must be materially increased.
Special Mention for "E46."
There would appear to be a future for a type of vehicle suited for delivery work in the country in cases where speed on the road is of secondary importance, where capital outlay and run fling costs are required to be reduced to the minimum, and where the loads to be carried would not exceed three tons. The majority of petrol lorries, being a very high-class engineering product, do not fulfil these conditions, and manufacturers might well turn their attention to a cheaper and slower class of vehicle, an excellent example of which was submitted (E 48), which, though capable of improvement and simplification, is worthy of special commendation.
We are glad that the Judges have thought it well to direct particular attention to the behaviour of this wagon, which was entered by T. C. Aveling and Company, Limited of Birmingham, for it should serve a variety of purposes where regular travelling and low cost of operation weigh more with the user than appearance, speed, and smooth running.
The Use of Heavier Hydro-carbons.
The Trials have demonstrated that petroleum fuel can he successfully used for internal combusion engined lorries in lieu of petrol ).petroleum spirit) ; the relative price of thiese fuels renders it desirable that more general attention should be paid by manufacturers to the possibilities of less volatile fuels, which possess the additional advantage of greater safety in storage and handling.
We would here remind our readers that the Ryknield Company's five-ton lorry (F55) employed a cheap fuel known as British turpentine, the makers applying the description " crude oil "to it though we think this hardly met the case. Of course, in such instances, it is important that prospective purchasers should be satisfied as to the volume of available supplies, and the likelihood of a continued low price.
Long-distance Work.
It is regretted that no tractor fitted with an internal combustion engine was entered in the Trials. The steam vehicle as at present constructed requires to pick up water at frequent intervals, generally not exceeding 20 to 30 miles. In Great Britain this presents no difficulty, but in the Colonies and elsewhere abroad, where mechanical transport can be and is being developed, such facilities for water may not exist. The internal combustion engine, or a steam vehicle fitted with a condenser, is there a necessity, as its use enables the radius of action of the vehicle to be increased to distances exceeding even 150 miles, the limit depending on the capacity of the fuel andwater tanks.
Detail Advances Since 1898 at Liverpool.
As regards the details of construction and design of the vehicles that competed in the Trials, it was evident that a very great improvement all round has been made during the past few years. This was notably the case in the matter of wheels, which the earlier Trials of the heavy vehicles in this country had proved themselves to be in many cases very defective, and the cause of much trouble, A marked improvement was generally apparent in the attention paid to details such as wiring, accessibility of nuts, bolts, etc., and ease of removal of those parts which require most attention; there were, however, a few vehicles in which such points had been totally neglected.
Ease of Control and Facility of Manipulation.
A few manufacturers had carefully studied the relative positions of the driver and the operating levers, pedals, steering wheel, etc., but in many cases the pedals were in such a position that only with the greatest discomfort could they be reached by a driver of average build. The practice of having on the "dash "
engine-control, levers, hand pumps, oil taps; etc., which require frequent actuation, should be discontinued. There is no doubt that the driver possessed of only moderate skill must be catered for, and more attention in many cases was required in this respect.
Brakes.
As regards brakes, there was a considerable variation in the efficiency apparently thought necessary by different rnanotactuners. Generally, brake surfaces should be increased and provision made to keep them free from grease.
Compensation of the back brakes should be arranged for without employing wire cable or the large number. of pinned connections used in some of the vehicles. Both foot and hand brakes should be provided with simple means of adjustment without the removal of any part ; this is a necessity for every vehicle, and the renewal of blocks or shoes with the minimum of labour and expense is a desideratum. No single vehicle can be considered ideal in these respects.
We notice that the Judges make reference to the matter of brake adjustment. Close observers of events during the Trials will recollect that some of these adjustments were so very easy of accomplishment, that they practically escaped notice. This facility being present, no doubt the makers in question deserved to reap the benefit of their "having rendered it such a simple matter for the driver to keep them in correct adjustment, and to lose no marks.
Steering Gear.
Steering coupling-rods were not in many cases situated behind the front axle as they should be.
Too Much Overhang.
It was noticed that the overhang of many of the bodies was excessive.This practice, probably followed to gain adhesion, entails an excess of weight being carried on the back axle, causing damage to roads and undesirable stresses in the vehicle.
Such overhang, of course, brings into play the additional factor of undue wear upon the back tires, unless their section is increased correspondingly, but nothing can overcome the consequential strains, on both tires and wheels, when corners are turned at customary speeds. There is, accordingly, every reason to invite observance of this recommendation.
Access to Machinery.
More attention is required in the majority of cases as regardsthe accessibility of the machinery under the platform ; in many cases it was impossible to gain access to those parts withoutdisturbing the load.
The Avoidance of Nuisance from the Exhaust.
While several of the vehicles showed practical freedom from nuisance to the public e.g., oil dropping and emission of vapour, others left much to be desired in this respect. This is a matter of importance.
The direction in which the exhaust is emitted requires the of many manufacturers ; in certain types of vehicles it is possible to arrange this vertically upwards above the load.
The reconunendation upon the use of vertically-directed exhausts has much to be said in its favour, but it renders standardisation most difficult. Where the exhaust pipe is placed horizontally below the frame, the lengths of piping, bends, sockets, etc., are uniform for whatever batch of chassis may be coming through the shops, whereas a change to the overhead type would involve variations to suit different bodies and classes of loads.
Engine Governing in Relation to Road Wheels.
A system of control whereby the speed of the engine can be governed by the speed of the road wheels is suggested as worthy of consideration.
Such a system -of governing is, unfortunately, subject tothe drawback of a means to introduce personal control for hill-climbing, as a high engine speed is then required in relation to the revolutions of the road wheels.
Lubricators and Lubrication.
Stauffer grease-cups were fitted indiscriminately and in a most lavish manner to parts requiring but little lubrication ; they were lost or broken to a large extent. The proper lubrication of such parts should be originally provided for by the designer, and not effected by subsequent addition of projecting pieces. Theuse of syphon oil-boxes is worthy of consideration.
Though it has been conclusively proved that the application .of forced lubrication to the engines conduces to lower cost of running and of maintenance, few of the competing vehicles were so fitted.
Lack of elementary knowledge was shown irt one or two cases by oil grooves being placed in bearings in such a position as to be useless.
Ignition Fittings.
The commutators in the primary circuits, and the distributors in the secondary circuits, were poor in design, and insufficiently supported in their bearings, and unsuited for use for commercial Work.
Water Circulation for Cooling.
Pumps for water circulation were noticed (a) of insufficient .size ; (6) with bearings unduly overhung; (c) bearings at one 'end of the spindle only. The ideal 'vehicle would not have a pump at all, and it was proved in the Trials that this was quite -compatible With efficient operation.
We have already illustrated in THE COMMERCIAL MOTOR" a number of commercial vehicles in which no pump is employed, the thermo-syphon principle being capable of satisfactory application so long as the necessary cross-section is maintained in the pipes, and the disposition of the parts of the system are arranged so as to avoid sudden bends.
Inadequate Connections.
The connections between the gear.changing lever and the gear box were in most vehicles of a wholly inadequate character; they should be such that the full meshing of the teeth of the gear wheels is ensured without frequent adjustment. This is of vital importance to a commercial_ vehicle.
We should regard the inadequacy as being more generally due to. an excessive number of parts, pins, and joints, in the change-speed striking gear, and there is certainly room for improvement in many cases.
The excessive wear in some of the jointed couplings transmitting the drive was due partly to unsuitable material, but mainly to the driving shafts not being designed to be in a line when the vehicle is fully loaded.
Another cause of wear is the smallness of the actual wearing surfaces, even when the right material is employed. Excessive intensities of pressure, with consequent difficulties of lubrication, really cause most of this trouble.
A Question of Suspension.
The attachment of suspension springs in some vehicles was such as to set up torsional stresses in the frames ; the shackling of the rear springs at the forward end in place of the rear end is worthy of further investigation.
We do not quite follow this recommendation, because the practice of shackling both end S of the rear springs, or of putting them in slippers, is very common. The Judges, possibly, intended to suggest the shackling of the forward -ends of the front springs, their rear ends then being secured rigidly to the frame, and this would certainty tend to reduce the difference between the vertical paths of the front axle and of the forward end of the steering rod.
Exposed Gears.
The fibre gear wheels used were in the majority of cases capable of considerable improvement, and where carried on separate short spindles were not always provided with adequate lubrication for their beatings.
Stouter Lamps Wanted.
Some oil lamps were fitted which were quite inadequate for .commercial work or for speeds exceeding eight miles per hour. The practice of fitting tail lamps in exposed positions where they are liable to damage should be avoided, and their position .should be clear of doors and tail boards.
The Spring-mounting of Tractors.
With reference to the tractors a better spring suspension is desirable and a properly compensated drive to allow free movement on the springs is necessary; the practice of allowing varialion of pitch in the gear drive to give this compensation is not desirable.
How to Save Weight.
It has been contended that the legal limit of tare weight is responsible for lack of improvement in this direction, but much weight can be saved by the employment of higher-class material, and manufacturers are referred to the specification* for material
used in the construction of railway rolling stock issued by the British Engineering Standards Committee. The reduction of the tare weight of the tractor is of primary importance, so that a sufficient tare weight may remain for the trailer under present legal condi-lions, and this can be done without reducing the adhesion below that required for the load that can legally be hauled.
Drawbar Attachment.
The very important point of the mode of attachment of the drawbar of the tractors was in no case perfectly satisfactory; it should have a bearing right round the hornblocks and should not bear on the hack axle. These bars should not be anywhere riveted to the rear tank, which should itself be strutted to take side stresses imposed by the drawbar when the pull from the wagon is at an angle to the direction of movement of the tractor.
Elaborate Finish Unnecessary.
For commercial purposes a fine finish on other than working parts is unnecessary and adds to the cost of production ; in this connection the amount of brass work and number of parts requiring to be kept polished were in some cases excessive ; a standard commercial vehicle must be produced at a minimum cost and be maintained with minimum labour; extra finish and brass work -(for the purpose of rnere appearance) can be supplied when required by the purchaser.
The Penalty of Work in Confined Spaces.
It was noted that drivers still continue to use the steering gear when the vehicle is at rest instead of waiting for it to gather way, a practice ,which should be allowed for in future designs.
This practice should not be allowed to grow upon any man to the extent of its becoming a custom when no occasion exists, but many a driver of a commercial vehicle has no alternative but to lock the front wheels when the vehicle is at rest—as, for example, when he is manceuvring in a confined space.
The Judges Markings.
In the abbreviated report relating to each vehicle which completed the Trials, mention is made of the subjects tinder which they were highly commended or commended. In this respect it must be noted that the consideration of the qualifications of the vehicles has been taken class by class and not as a whole. Hence, exceptional performance on some one subject—e.g., cost per ton mile—may place a vehicle in a very high position in its class.
Attention should be drawn to the fact, shown only by the mileage given, that on the 11th October most of the vehicles covered the route from Bedford to Baldock twice over.
We are sorry that the details of the cost per net ton-mile are not stated in any part of the report, although we are informed that they were worked out for the guidance of the judges in the matter of the awards. Following the precedent of other reports of a similar character, it would have been a great help and guide had such figures, even at the risk of a certain amount of criticism from disappointed competitors, been included. We cannot divest ourselves of the feeling that certain exceptional fuel performances may have had an undue effect, such as that which the Judges name, and it is doubtful whether these same exceptional eccnomies would have been achieved in the hands of anybody but an expert in the hand regulation of the fuel supply.
Rapid Di smantling and Reassembling.
The greatest credit is due to those employed in totally dismantling and reassembling the fifty vehicles on conclusion of the Trial, in that, excluding the two days reserved for detailed examination by the judges, the whole of this work was carried out in three and a-half days.
Heavy Expenditure Fully Justified.
In conclusion, it may be said that the Commercial Vehicle Trials have fully justified the heavy expenditure of time and money devoted to them, and it is believed that the opportunity given to the entrants to study the behaviour of their own and other competitors' vehicles under the strict conditions of the Trials will result in improved design and benefit not only to themselves but to the ever-increasing number of those to whom facilities for mechanical transport on common roads are of importance.
By order of the Judges, 3. W. OkEE, Secretary.