THE MOTOR WORLD

New Zealand Times, Volume XLIII, Issue 10086, 27 September 1918, Page 8

THE MOTOR WORLD

ENGINE CAPACITY POWER DEVELOPMENT XN CYCLES What is to he regarded as the "maximum’' in theway of usefulness where the horse-power capacity of a motorcycle is concernedf That is a question which can be easily disposed of it answered by the rule which applies to usage and the practice commonly followed. Nominally, at all events, 8 h.p., or, as some prefer to put it, 7-9 h.p., is the highest rated horse-power attributed to the most powerful models at present on the market, although they have gone as high as 10 and even 12 h.p. in the United States. D aln.g with tue bioad aspect of horse-power ratings and the actual power development of motor'oyole engines, it is necessary to draw a line of distinction between the two. It may 'be accepted with safety that a motor-cycle fitted with, a so-called 8 h.p. engine is in reality propelled by one of at least one-third greater power, and we know from practical experience that the difference between rating and actual ontpnt is even a wider one than this. A heavy side-car outfit, well loaded up with passenger and luggage, and taking Into consideration the many factors which help to throw added work upon the engine, such as road profile and weather conditions, requires a fairiy large engine to meet all requirements. In nprmal circumstances an 8 h.p. engine (according to rating) is ample to meet all demands. One of 6 h.p., being really about 8-9 h.p., can do practically all that is required of it, and a smaller one still with suitable gearing will leave out little to be desired. Reserve .power, of which so much is heard, provides a comfortable feeling for the driver who la out in all weathers and has to keep up a fairly fast schedule when on-business bent, but for all ordinary purposes the reserve is provided by the gear box as well as in the engine, the two working together and < forming in combination a means of providing against overload to an extent which is hardly ever likely to bo overstrained.

ENGINE WEIGHT PER HORSEPOWER.

The following comparative list of tlu weight per horse-power of the vanoutypes of engines is instructive and interesting ■ . , , ~ Weight lb per n,u Aerop’ane engines .... 1 I- 63 Aero engines lor racing cars £4 Petrol engines for racing oars 7j Petrol engines for motor-cars ...... 15 Steam reciprocating engines for

destroyers * fjj Diesel engines for submarines ... 50 Turbines (with boilers and auxiliaries) 200 Diesel engines for cargo boats (with all auxiliaries) Diesel engines for cargo boats (without auxiliaries) 250 Triple-expansion steam engines eluding boilers and auxiliaries) 450 Triple-expansion steam engines for cargo boat (without boilers and auxiliaries) 130 UNDER-TYRED MOTOR CYCLES.

An Australian writer says he has always advocated larger tyres for motor-cycles, especially for high powered twins. .4 factor contributing to the success of the American passenger motor-cycles in this country has undoubtedly been the circumstance that they are fitted with 2tiin by Sin wheels. litoglish markers have al ways been inclined to under-tyro theft machines, and this is particularly the case with the higher-powered outfits on the one hand and light-weight machines on the other. Two reasons have usually been assigned for .this: The first is that to fit larger wheels and tyres would t Id to the initial cost of the machine. Seeing that, as war time experience has proved, people do not mind paying a little ex era for an article if .that article is wortl. the additional cost, this point is not o, very serious one. The second objection is that, in order to fit larger tyres, i' would in all probability entail altering the design of the frame. This in normal times, with the factory working to produce a sufficient number of machines to meet the demand, would be a much more serious objection. At the present time.

when the post-war model is very much in embryo, it is possible completely to redesign the frame to take larger tyres. Even with the lower-powered machines it might be advantageous to fit wider tyres, if not larger wheels, but we do rot think there is very much doubt tl at 28in bv Sin wheels and tyres could be standardised and adopted for all sizes above Bi-h.p. or 4-h.p At the present moment the question of standardising American rim sizes is under consideration bv the manufacturers. The matter is also one to which manufacturers ot high-powered passenger machines «re giving some consideration, and we think it not at all unlikely that two sizes in wheels only will be in general use on post-war machines, namely 26in x £Jin for powers up to 4-h p.. and 28in x S'a for higher powers. Even for ultra-light-weight machines it would not be a', disadvantage if the former comparative!'large sizes • wore adopted as _ standard Certainly, light-weight machines lave been under-tyred in the past. SOME STARTTNO HISTORY. Nearly every car owner knows that ir T. A. Wizard had a great deal U o with the starting battery,- but only few know of the part/he took in ruakng the electric starting and lighting 'racticahle for automobiles. Long before •lectr'c lighting was seriously considered, Tr Willard had perfected a battery for ighting railway conches, and whs familiar with every detail of the system. This was in the days when all motorcars were autos and had to be "wound ur>”—when acetylene lights wore the best to be had. and the spark came from a set of dry batteries. Electricity had one bin job on the automobile that it

."idti't have on th« Pullman—that wat starting. As starting, ©ven with th« most economical motor, took considerable current, the battery had to be kept well chara«d. On? of Mr WUlarH'e biggest jobs in uutoraobilo starting and lighting was to make a generator that would keep the. imttery on charge all the time except <vhen the engine wae going very slowly. Eji develops the extra-brush system of regulation which regulates the charging" regardless of the engine speed. Another important thin? Mr Willant <lid was to help perfect the small lowidtage lamps that were used for head \nd tail lights and for light on the dash. He. not only advocated low-voltage lamp«, but proved that better results were pos-t sible with 6 or 12 volt systems than with the earlier 24-volt system. The higher voltages are now rarely found. The most recent, and perhap* the greatest contribution Mr Willard eror nada to automobile electric • lighting ja the treaded rubber insulation. By this ■ventjon Ihe use of durable long-lived rubbei insulation in automobile starting 'lid lighting butteries was made possible "'.-!■" t.h»> ft>«t t'mp. In a w->y that waa '"■Vfiraeterislic of Mr Willard's ingenuity 1 ? "solved • the problem of inserting •early 200.000 tiny threads in each of he batterv in«tiltttor». Ask Messm "howns Bollinger .and Co., Ltd., Well. ngbon, agents. . fc- ' further particulars.*