The Coming 0 'Electric Transmission.
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A little more than 18 months ago, or, to be precise, in our Editorial columns of the 4th September, 1905, we expressed the view that " in the petrol-electric system the greatest possibilities of development lie." We subsequently advanced other cogent arguments in order to show that workMg conditions called for something more satisfactory than a SOX of step gears, and it was in our issue of the loth of May last that we reiterated the conviction, under the same title as the one we now employ again, that transmission pro)lems would he effectively solved by the adoption of suitable petrol-electric transmission sets. We recollect that our views were ridiculed by some of our contemporaries at the ime, but, after an interval of about six months, the usual ;flange of front occurred, and our predictions were repeated )y those who so often flatter us in the only sincere way. Apropos the subject of petrol-electric transmission, an ateresting comparative article, the first of two from the pen If Dr.. Alfred Hay, M.I.E.E., in which the salient leaures of the several competing systems are to be briefly disaissed, will be found in this issue. Dr. Hay, we observe, wily touches upon the commercial side of the proposition, Ind it is upon that feature that we desire to pass a few renarks at this juncture. All motorbus companies are con:erned with the question of ultimate economy, for this is to hem the all-important consideration, whilst their work )ffers a much more promising field, as compared with van Jr lorry services, for the class of transmission under review. .t appears that the first cost of a suitable transmission set or a double-deck omnibus varies from .4;125 to £275; lence, we may take .200 as a mean. This outlay is in .espect of parts Which will replace the ordinary gear-box of t petrol-driven vehicle, the fly-wheel, clutch, change-speed connections and part of the brake gear, but it will add, in any event, something like an average of .Ltoo to the first cost. If an existing vehicle is converted to the new system, the discarding of the old parts, and the fitting of new ones, may increase this first cost very considerably. It is clear, however, that nothing can be said in favour of a petrolelectric transmission set on the score of first cost, and its advocates have admitted this from the outset. We accordingly turn to the even more important question of running cost, which includes fuel, lubrication and maintenance charges. Adherents of systems in which a direct mechanical drive is obtained for ordinary running argue that their fuel consumption cannot in any circumstances exceed that of a geared vehicle, owing to the fact that through driving, from engine to transverse shaft, or to back axle, is employed so largely, the electric drive being required for acceleration and hill-climbing only. Adherents of the all-electric drive, where the whole of the running is done in the absence of through mechanical connection between engine and transverse shaft, or live back axle, maintain, on the other hand, that they are well able to keep down their fuel consumption owing to their ability to take advantage of low enginespeeds in relation to those of the vehicle. Our own opinion, and one at which we have arrived after both trial and examination of the several leading systems, is that, whilst none of them should use appreciably more fuel than an ordinary petrol-driven vehicle with step gears, those in which the engine can be started from the seat will be slightly more economical in fuel consumption, under the conditions of London traffic, than those in which the engine has to be kept running all the time. For country services, and for long runs over normal roads, even of an undulating character, we are inclined to favour the introduction of the through mechanical drive, for the best efficiency with an allelectric drive, between engine and road wheels, cannot he other than at least 25 per cent, less efficient than the through mechanical drive. It is economy of maintenance charges that will commend electric transmission sets to operating companies. These sets, which are so easily interchangeable, will practically eliminate the driver problem, and they will cut down maintenance charges by something like 75 per cent. per annum, startling as this assertion may appear. Much of this saving will be due to the automatic acceleration with an electric set, and to the .absence of the enormous shocks and stresses which are set up by the average manipulation of a mechanical foot-clutch and a set of step gears. We are satisfied that no one petrol-electric system, any more than a single arrangement of any such system, will prove of universal application, and there should be room for all except those. who seek to retain a system of control in which the main circuit is frequently broken. Control by the variation or the shortcircuiting of the current supplied to the windings of the generator magnets promises to be the most favoured method. We have every reason to be gratified at the remarkable advance that has been recently made by the several designers of petrol-electric systems, having regard to our advocacy of the change from mechanical gears to electric, gears, and, whilst recognising the unquestioned merits of several con
tinuous-current combinations, we have seen no valid reason for the abrogation of our declarations as to the inherent and peculiar merits of polyphase, alternating-current, induction motors for use in motorbus chassis.
After the Show is Over.
Some of our principal supporters have communicated their views about the exhibition to our columns, and they will be found on pages 72 and 73, whilst Mr. Henry Sturmey, the father of automobile journalism, makes some interesting observations on this page. " THE Commuttetat, MoTort " has, in common with so many other exhibitors at Olympia, every cause to be satisfied with the results. The demand for both our show numbers was beyond our highest estimates, arid both issues were sold out completely at our stand, the first on the night of the 9th instant, and the second on the night of the 15th instant. Our complete show report, as we repeat elsewhere in this issue, Was not Out late, notwithstanding the fact that it necessitated an almost incredible amount of extra work for the whole of the Editorial staff, who, apart from the opportunities afforded
while the vehicles were being staged at Kensington, had only three clear days during show-time for the taking of notes, the preparation of special sketches, and the securing Of photographs. Among the many congratulations which have been conveyed to u.s as to the arrangement and compilation of the reports in question, none has been more gratifying to us than those in which we have been corna plimen Led upon the system that was adopted, and upon the fact that the complete report, running to 84 pages of matter and illustrations, was on sale shortly after it o'clock on Monday morning the Nth instant. This journal is now concerned to meet the requirements of its fifteen hundred. new readers and subscribers who have become acquainted with our pages during the past fortnight, and who, almost without exception, represent intending purchasers of commercial motors, There must be, of course, many unsettled points in the minds of those who turn to study the question of mechanical road haulage for the first time, and we wish to. assure new readers that advice of any kind will be given by us, without charge, either through the columns of this journal, or direct by post to any enquirer who may prefer to ask us to adopt that course.