MOTORING AND CYCLING.

Taranaki Daily News, 10 August 1917, Page 7

MOTORING AND CYCLING.

NEWS AND NOTES. Remarkable developments have taken place in the construction of aeroplane engines .in England since 1914. One ol finest aero engines now made is a 476 brake horsepower 18 oylinder "Sunbeam." Mu« power unit is made irp on three rows of six cylinders, all eperating on the one crankshaft Two earbursttors are used to each row of cylinders, each of which is provided with four valves, two exhaust and two inlet. Sis magnetos are used. This 13 the type of engine that is enabling the British aviators to maintain the air supremacy on the western front. In this connection it is interesting to note that some of the recent air fighting has taken place at an altitude of over 21,000 or four miles high. The power developed by a motorcycle engine depends in large ratio upon its speed in revolutions per minute, and the (! .igner has to take this 3trictly into account in selecting the dimensional characteristics of the cylinder as they apply to the ibjore and stroke. We hear sometimes of one engine being much faster than another; not as regards tho propulsion of the motor-cycle, for thero other factors are introduced, but in it» own speed or rate of turning oyer, Th» gear ratio determines to a I very Urge- extant, indeed almost en'tktif, the number of engine revolutions jar minute "»t a given speed of tho machine aa a whole, but if tho engine is being run independently of the road wheels by means of the clutch or ro-

movnl of the transmission medium, then undoubtedly one engine will revolve more rapidly than another of the same pvopovtkm and general''character. The fcwjjanatioii must in such a case be 'ufight among reasons which have nothing to do with, propulsive factors, such being in the circumstances eliminated, •and it will be found in the greater accuracy of design and lesser fricxional effects which one engine possesses as compared with another. The use of •ball and roller bearings for main shafts and connecting rods increases the freedom and liveliness of an engine, and indeed anything tending to remove friction has, as might be expected, the same results. When the bearings have ivbeeti in use for long periods the engine generally has become somewhat sluggish, The effect. produced on its speed by flmhisg out with parafin is remarkable. It oeoqis to Infuse new life into the •Ogint and the response to the opening *f tho throttle, no matter how alight the lattar may be, is noticeably improved; ■the clogging effect of tho stale, thick ibij has been removed and the frictional or braking effect which such entails OYjsrcome. Thia is of course reflected in sflperier running when th* machine is o& the xm&, and if the process were *em*ied more often than is the case on

the average, we ahould hc*r less oft fallings off in speed and power. Having found British motor-cycles superior to her own, France has mounted ali of her military motor-cyclists on the Britiih-tmilt machines.

At any rate the price of high grade cotton is advancing, almost immediate rises Jn cost of motor and cycle tyres must necessarily follow. Latest advices from America show a further hardening in the cotton market. The canvas is now more than double the ; pries it was a few months back. What ■with increased cost of petrol and in-. ,«83sed cost of tyres the outlook for Mjstoiiats is not too bright. Practically all* the leading British motor-cycle factories are at the present time running out machines on a largs Russian military order. It ia worth! while noting-that the motor-cycles are all of the heavy twin type indicative of th» fact that while light-weight military models predominate on the western fronts, the heavy-weight machine evidently conies into its own in the eastern war field. i

France haa 14,000 touring cars in the service of her army, which, cost approximately about £6OO a year each to run for spares, tyres, petrol oil, etc, The United States Government recently called for tenders for the supply of » kr.ge number of touring care for the use of her army in France. ' As illustrating the immense output of someof the big American car makers, it is; interesting to note how some of the concerns are prepared to deliver, The Overland Company, 110 cars a day, Podge, 200 a day, Studebaker, 950 per month, Scrippe-Booth, 100 per week; Saxon, 4» per daj, etc. Most of the. manufacturers quoted the government 25 per cent, off ljwt-priee. Many erroneous impressions have gone iout with regard to the work amured have been doing on the Ireneh frost. So far w light armored cars larji concerned there has scarcely been a [gbigle ease of their being used on the Western front, because the ground is %> torn up, due to shell fire, that it is impossible for so large a target as a,' Ught armored car to share in manoeuver-1 ;ing work. The protection of such cars J lis very limited even to the smallest anM I'munition. This layk of their use on the : i western front can scarcely be considered #n indication of their lack of usefulness, ;*owevqr. feather it must be considered' a restriction on their use due to uniiaYorftble conditions. On the other hand tthfe jnotor trucks fitted with anti-air- ■ «raft guns' have heen doing steady cdn|*fei«a£ work all the time. These trucks I ,«re eseratiag in connection with fleets j ijf tajwe, protecting the advance of tanks 'mm wstile airplane observation and 'oonfciol fo». These trucks are also ] in repair work on tanks. Wiwrever the tanks are the anti-aircraft r-ti'tuDu are near at hand. la April Australia bought 303 touring cars from America of a value of £ifljM. In the same month England imported eleven, worth £6,125, but she bought 418 motor trucks at a cost of £258,110. The American car exports for April alone show a decline of £200,000. ' '