OPINIONS FROM OTHERS.
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The Editor invites correspondence on all subjects connected with the use of commercial motors. Letters should be on on& side of the paper only and typewritten by preference. The right of abbreviationis reserved, and no responsibility for views expressed is accepted.
Unconventional Design.
The Editor, THE COMMERCIAL MOTOR.
[1607] arn tempted to pen a few observa
tions in support of the " massed' arguments by your • excellent contributor "The Inspector" in his article "Unconventional Design." The degree of specialization attained from extended practice will bear,heavily in post-war design, aiming at the production of the successful machine for the road. Perhaps on account of these complex inter-relationships it will be necessary to produce a model . which throughout is con ceived afresh. Further,"steel will be too valuable a material to be used carelessly, and there is no doubt that an enormous amount has been wasted by being
put in the wrong place. A reconsideration of the whole question of design will naturally entail an investigation of the fundamental. factors, and theknowledge gained can only serve to elarify the problems in the mind of the' designer.
As rightly expounded by "The Inspector," it is a relatively easy thing to improve to some extent bn anye given design by the embodiment of more or less important refinements or additions. But it is not so easy a task and certainly not one so frequently undertaken to produce a model which throughout is conceived afresh. There cannot be any finality in design until the perfect machine, be it for road, rail or air, is evolved and, as "The Inspector" states,
Messrs. Garrett's a.re to be commended for breaking away from convention in design to attain this end. In my opinion. road crusts are damaged and disturbed to a vatt degree by vertical forces. These
forces can; and should be, absorbed by the suspension design of springs and axles..
In support of my theory I would call your Attention to the dilapidated state of the -permanent tramway
in Birmingham. At each joint in file rails, in some instances, the ends of the rails are flattened out, and have Sunk much below the level of the road. As . each wheel of a tram passes over the joint, the end of the rail receives a blow as from a steam hammer, owing to the wheel being unable to recoil from the angular blow received. The -construction of roads has ever been a bone of contention between the user and the powers that be. I venture to recall a case in point. In 1633 Richard
Foley, of Dudley, Worcestershire, in an action brought against Whorwood, the lord of the Manor of Stourton (whose tenant Foley was) and one Warren, for right of way and access to his mill, one part of the defence was as follows :—" Butt with his great carriage of Ironstone, Iron, and charcoles, he the said complainant dot-he, much Spoyle and ympayre the Kynge's highways, to the great tante and annoyance of the passengers, and inhabitants thereabouts and dothe not repaire and amend the same."
Given good roads and crust design the wear and tear resulting from the passage thereon of heavytype traffic will be reduced to a negligible factor if the correct method of suspension be adopted for the vehicles, and then it may be said we have taken, a progressive step to the elucidation of the p-erfect machine.—Yours faithfully,
ORLANDO RALLS.
Suction Gas for Motors.
The EditOr, THE COMMERCIAL MOTOR.
ti608] Sir,—I was very interested in the views of my critics of the article which I wrote in your issue of the 30th May, particularly those expressed by Major David J. Smith, M.Inst.A.E., which appeared in your publication for the 13th June. I would point out to
him that the type of engine I had in mind -when I wrote my article was of the hit-and-miss type. I was, of course, fully aware, when the plant to which I refer was installed, that Crossley and other firstclass makes of suction-gas engines are fitted with a variable gas governor ; but even this factor does not alter the outstanding point that the conditions of working for both petrol and gas engines are not iden tical—a fact which. will be obvious to those who possess a knowledge of both petrol motor and gas engine construction. Major Smith refers to suction-gas plants which have been running on munition work practically night and day for many months without requiring such constant cleaning as I mention. I know there are cases of this kind; in fact, I ran a Crossley plant in 1911 for over six months without drawing the fire, and I know that this is by no means a record performance. I was, perhaps, unwise in wording the phrases as I did re carbonizing, for I did not intend to convey the
impression 'that the combustion chambers were constantly fouling up. He says that any unpleasantness experienced in
the vicinity of the vehicle while the producer is being fanned up is purely imaginary, as a very small volume of gas projected into the open air would be absolutely unnoticeable. If that is the case, might I question why it was that when I was in charge of a Plant which was erected over 100 yards from any dwelling-house, the localcouncil compelled us, on account of corn
-plaint by the residents, to run the blow-off pipe up a .smoke. stack over 60 ft. high.
I -am not Mixing bituminous coal -with anthracite -coal, as Major 'Smith suggests. • My statethent on this -point is quite clear, for it is altogether unsuitable for 'suction or pressure producers. He says that there is 'practically no tar in anthracite coal, Whereas .Mr. -John Stewart, in a well-informed article on page 340 of the same issue, says that there is. SO far as the question-of weight is concerned, it WAS obvious, and,moreover, was so stated, that my re-marks were based on -stationary producer -practice. fay cognizant, in -spite of Major Smith's sug-gesticin to the contrary.; of the.quality of the present .coal-gas being supplied to commercial 'vehicles. He must be &Ware,. if he is. a regUlar reader of the ".0.M." or " The Motor," that I operated the first van to run on coal-gas in London. I have converted in all ten ears to coal-gas, including a Rolls-Royce. Much of this coal-gas, he says, is no better than proAluder gas from best anthracite. I have worked a well-known suction-gas producer of 80 h.p: on " Coalite," a kind of-semi-coke, which was produced from a very low-grade slack, -and it gave a very much better gas than the best anthracite. As regards loss of power, I leave him to reconcile the engine makers'
figures. : .
Major Smith's advice is not lost on me. Some of my experiences with gas plants were gained long ago —in fact, they began in 1902. I _have tried to keep in tonal with the latest improvements, but I do not work in a munition factory, and I have not had an opportunity of observing the improvements made in the last four years. I am aware that the tendency is to construct all, open-hearth plants, thus eliminating all heavy doors at-the bottom of the plant, • In Mr. John Stewart's letter, on page 850, he refers to my remarks re the -little troubles connected with gas Nants. The particular case I had in mind was no fault either in the construction or lay-out of the plant, but the conditions of working—the same :trouble re carburetters and ignition systems in this ease doe's not apply, and no common-sense supervision on the part of the engineer-in-charge can make up for the thick-headedness of some managers and managing directors, who will have their way in this or that case. Instances of this sort have been Wrought to my notice from the page's of "The Power User," but, happily, they are constantly decreasing. I had. intended ,te. have run our latest converted car on producer gas -from a pressure plant, but, unfortunately, my other work ketps me to busy to undertake it, the plant riot-being where %am at prestit. employed. • .
I shall watch the progress of producer gas for road transport with great interest. There are one or two points of' great interest to me, and I should like to knew how they will eventually be overcome.
• One point inMajorSmith's letter calls for coinmerit.. He says that he suecessfully. mastered this problem six ,years ago. Night I question why more has not been heard of it and yet. Messrs. Stewart',:-.1 Gas Producer Co. are still in the experimental stage
—Yours faithfully, FRANK E. RAYMOND.
Pneumatic Tyres fclr Commercial Vehicles. '
The Editor, THE COMMERCIAL MOTOR.
a 1 11609] Sir,—AsI ,I.T.ye had ;some experience _with pneumatic tyres on commercial vehicles, . ,
Ibeg to offer my humble opinion of sante. • Having upwards of 40 lorries on the road, I decided after having some radiator, front spring and steving gear troubles, to fit pnetiinatic tyres to some of my
2 and 21--ton lorries. The results were very satisfacory, and even remarkable_, not Only in the way. of rnileage (the average for a 2t-ton lorry being 8000 miles on &pair of 895 by 150 Diamond Tread Goodyear), but. also in diminishing the radiator and steering troubles o nil.
I have -also a 2-ton lorry running on a front nd 8-in. hack Goodyear pneumatic. The rear wheels ive an average of 4500 miles, the average running oad being 30 cwt., and it is surprising to, see the dd.erence these tyres have effected in the matter of year and tear of both body and chassis, in comparison
vith similar vehicles fitted with solid tyres. I would also mention I am running a fleet of twowheeled trailers, the oldest one having aoomnplished distance of 25,000 miles on Goodyear pneumatic wins 895 by 150.—Yours faithfully, B. N. TAYLOR. Edgware.