Dt:Ct.MBJ-.tt 28TH , 1907.
THE AUTOCAR B 3ournal publisbeb tn tbe interests of tbe mecbanicau~ propelleb roab carrtagt.
EDITED BY H. WALTER STANER.
No. 636. VoL. XIX. SATURDAY, DECEMBER 28TH, r907. [PRICE 3D.
THE · AUTOCAR.
(P ublished Weekly.)
Registered as a newspaper for transmission in the United Kingdom,
Entered as secon'd-class matter in the New ~ork (N.Y. ) Post O!nce.
EDITORIAL OFF ICE :
COVENTRY.
PUBUSHING OFFICES :
2 0, TUDOR STREET, Lt >NDON, E .C., ENGLAND.
P' NOTES
CONTENTS.
PA.(iP
.. 1045-1046
USEFUL HI NTS AND TIPS : To DRIVERS OF MERCEDES CARS . .
1047
To THE ALPS ASD BACK (ILLUSTRATED) • •
• • 1048-1050
THE MOTOR UNI0:s': ITS POSITION AND FUTURE POLICY DEFINED ro51-1055 Ex PARTE 1056-1057 DISPROPORTIONATE FINr:s ON THE ROAD. BY OWEN JOHN A TEACHING CAR (ILLUSTRATED) A NEW DISTRIBUTER SET
1057 .. rn58-1059
ro59 1060
THE PRINCIPLES OF CARBURETTING AS DETERltlNED BY EXHAUST
GAS ANALYSIS AMERICAN RACING EVENTS . • CoRRESPONDENCE
. . 1061-1063
1064 .. 1065-1070
CONTINENTAL NOTES AND NEWS : THE MOTOR IN THE BELGIAN
ARMY-ACCENT OF MOUNT PRARION-PRINCE HENRY OF PRUSSIA ON AUTOMOBILISM
FLASHES • • CLUB DoINGS--:,REVIEWS THE PALHER CORD TYRE TRIAL TABULATED DETAILS OF CARS AT OLYMP IA SOME QUERrns AND REPLIES • .
1071 . 1072-1073
ro74 1074 .. ro75-1079
1080
" THE AUTOCAR " SUBSCRIPTION RATES : British I sles, I6~ . Abroad (thin paper editi o n). 22'.. Srl. per aooum .
/ Notes. The Royal A.C. Rat ing. We are glad to find that many of the leading manufacturers intend in the coming year to give the R.A.C. rating of all their engines in their catalogues. For instance, if the car is nominally known as the 18-22 h.p ., but comes out on the R.A.C. rating as 26 . 5, this information will also be given. In some cases, too, the R.A.C. h.p. will alone be given. A few of the more go-ahead makers have quoted R.A.C. rating in their 1907 catalogues, and we hope tha t in future practically everyone will accept the suggestion of the Society of Motor Manufac_turers · and g\J,/e this information. It will be remembexed that the R.A.C. rating formula is diameter of cylinder bore in inches squared, multiplied by the number of cylinders and divided by 2.5.
When th e Club formula was first introduced about a year ago, it was made perfectly clear that it was for rating only, and was not to be considered as an accurate or scientific calc ulatio n of h.p. It was merely to be used so that the public might arrive at the approximate power o.f any given engine in comparison with. others. It is not as we pointed out at the time, a perfect formula, though it. serves very well as a rough method to which all engi nes can be subjected, so that the purchaser in making comparisons can form a rough idea. o.f what he is actually buying, and the necessity for it has been brought about by the fact that some-in fact, mostmanufacturers under-rate their engines.
On the other hand, some makers quote a nominal h.p. which is as nearly as possible correct, while a very few indeed quote the maximum which their engines can give. In other words, there is no universal system among the manufacturers, so that the buyer never knows exactly what the nominal h.p.'s they give to their different engines really mean. For this purpose, therefore, the R.A.C. rating serves very well, but we consider. it most unsatisfactory when it is used in hill-climbing, or racing competitions, because it only necessitates that the competitors shall disclose the bore of their engines. This is a very great pity. To take one instance alone -Brooklands. All the classification is done upon bore alone, because the R.A.C. formula is used, and, co.nsequently, keen students of the results have learned very much less than they would have done if a formula had been used which took cognisance of strol_ce as well as bore. .
As things stand, the bore of all the successful cars is known, but in the vast majority o.f instances . the greatest doubt exists as to the stroke, and consequently many valuable lessons which mjght hav~ been learned .by automobile constructors generally are only known to a very few, in fact, in the majority of cases, only to the constructors of the successful cars. The same remarks apply with equal fo rce to all the hill-climbs in which the R.A.C. formula has been used. We make these remarks in no hypercritical spirit, but, as there appears to be every likelihood of the R .A.C. formula coming into general use, it seems a great pity that it should not be revised before it is too late to include stroke as well as bore. It is not a question of the ra.ting being wrong or useless, but ra ther of its being of far less service in ad".o/.Jcing knowledge than it might be, and we therefore tf ~nk that it should be revised.
Sidt -slip. In dealing recently with the question of the studded and plain tyre. we referred to the fact that some cars slipped very much less than others, and we suggested that an im-estigation of the whole question by the Royal Automobile Club would be a most useful work. Since then we have given the matter some further consi-deration , and we feel more than ever convinced that an investigafron of this kind would be of very great service. As the matter stands, it may be saia,· that there is one section of the motor worl<l which believei;
