MOTORS & MOTORING

Dominion, Volume 14, Issue 201, 20 May 1921, Page 9

MOTORS & MOTORING

(By

"Clutch.")

Motorists’ Taxes. What an enormous sum of money motorists throughout the world have to pay annually for the privilege of motoring on the public highways. In America, where 9,000,000 care ore registered,, the yearly car taxes amount to close on -£100,000,000. In England nearly •£6,000,000 is said by motorists in ear taxes, etc.

Starting From Cold. During the war period an interesting and effle-ctive device was adopted for starting aero engines from cold. This system has now been adopted by an English manufacturer who Aas placed on the markets a new engine starter. Its operation will Interest motorists. Tho idea behind it is to pump into that particular cylinder which is at rest in firing position a rich explosive mixture, and ignite this by means of a spark at tho plug. Screwed into tho side of the carburettor float chamber is a small jot surrounded by a kind of adjustable choke tube. This is connected to a hand pump on the dashboard of t”he vehicle, so as to bo operated from the driver’s seat. The pump has two valves, so that when

it is operated the consequent suction on the jet vapourises the fuel which forms ° mixture with the air and fills the pump. Pushing down the pump plunger then forces the mixture through the outlet valve to a container, which is simply a small pressure tank carried on the dashboard. From this container an outlet pipe leads to a small/ receptacle containing some fibrous material which traps any condensed fuel and acts as a wick carburettor. From this the gas passes to a distributing valve assembly, which consists of four small piston valves operated by cams. The distributing camshaft is operated by a

half-time sprocket on the magneto driving shaft, the cams being so arranged that they cause the valves to be opened in the same sequence as the inlet valves of the engine, and at the same time. Each outlet port of this distributing valve is connected by a copper tube to an opening in its respective cylinder, usually by the side of the plug. Where

tho pipe joins the cylinder it is provided with a small poppet typo valve which Beals it when tho engine is running. In order to provide the requisite, spark in the correct cylinder, the magneto is connected up to a dual ignition switch on the dashboard in such a manner that

operating the switch "earths” the magneto and connects the coil to tho magneto distributor. Thus the magneto is cut out and the spark is provided by a battery and. coil set carried on the dashboard. Reversing the switch, of course, cuts out the coil and brings ria the magneto. To .start the engine one merely pumps sufficient gas into the container to raise the pressure to about 151 b. per square inch; this means, say, half a dozen strokes. The gas Is automatically supplied to the required cylinder, and' it is only necessary to switch on the current from the coil, when the charge will be fired.. The next cylinder to come into firing position also receives a charge, which is flrod, and these two explosions ore all that is necessary to start the engine, which can then ba switched over on to the magneto. It is stated that this system is most effective, even in the coldest weather. It should be stated that, ,whon the engine is. running and 1 the pressure of the container has dropped, the distribut. ing valves remain at the top of thoh stroke, so that they are idle, and no wear is taking place. The choke tubs over the jet. can bo readily 'adjusted, so as to provide an extremely rich mix. ture iF desired, tho best position for any particular engine being determined by experiment. Spring Frame Motor-Cycles.

Those with experience of motor-cycle spring frames, or some of them, will know that weight distribution plays an even more important part therewith than is the case with the rigid type of frame. Assuming tho springs to bo of the plate or laminted pattern, there is a considerable difference in the stability of the machine when weight is added behind the frame proper, and this is especially felt when driving in traffic and sharp deviations from the straight have frequently to be made. There ia in auch circumstances a tendency for the motor-cycle to develop a "tail,” which in this connection on being interpreted means a whippiness of tho rear section of the machine, and a feeling, although perhaps a false one, that it is skidding When in reality it may not be doing eo. An ftXDßrf’. fpßfrpfl ■f'hron fionnrn+a

ah expert tested three separate motorcycles, each fitted with a spring frame planned on somewhat similar lines. One of the machines especially felt very insecure when ridden on greasy surfaces, and this was accentuated when a passenger took his seat on the carrier. Doubtless this was duo in some measure to the lifting of weight from the front wheel or its concomitant effect, and in any case great care had to be exercised to avoid a spill. Riding later over the Hama ground on a rigid-frame machine but otherwise under exactly tho same conditions, no difficulty of any kind was experienced, and this type undoubtedly scored on the ground of stability, engen-

dering a feeling of security which was altogether absent in the other model. On the other hand tho spring frame was noticeably better, from the point of view of shock absorption, with a pillion rider behind, the extra weight serving to bring tho springs more fully into,play, keeping the wheel down and throwing more work upon the springs. On dry, straight roads the motor-cycle so equipped was immeasurably the superior of tho rigid-frame one, and steering at high speeds by, literally speaking, one finger with two riders mounted, was a perfectly easy and safe task. There can bo no doubt that the efficiency of some motor-cycles fitted with spring frames is tn some directions dependent upon the dis-

tribution of its own and added weights upon tho wheelbase. Pillion carrying cannot bo said to improve the steering qualities of any machine, but, generally, speaking, in the hands of a thoroughly competent driver there is little or no risk even when an emergency arises and sudden turns have to be made. The difference, however, is as intimated above, very marked when it comes to driving a machine of this class, "two up,” through crowded thoroughfares, with perhaps a slightly greasy surface end one has to pick one’s way through a stream of other traffic, with, to make It worse, a train system operating on the routo. In such circumstances tho "solid” frame was preferable. Rear Windscreens.

Windscreens for the protection, and comfort of tho passengers in the rear seats of carg have attained, to great popularity at Home, and it is possible that, if their advantages wore better known in New Zealand these fitments would come into more general use. The rear seat is supposed to be the. seat of honour, and it is one in which the ladies and other respected people are put and yet it is tho more exposed place. With a rear screen the passengers are completely protected from wind, dust, and to some extent, from rain. There are various methods for constructing and mounting the rear screen, the more usual thing being to make it in three parts—a central window and two side windows—and to attach these to a pair of telescopic or hinged arms, which aro then bolted to the back of the front seats. In view of tho Toughness of our roads it is expedient to make of the fittings exceedingly staunch, ami if necessary to provide an anchorage on each side of the Tear seat to .restrain movement when the screen is fully tended.

Lighting-up time: To-day, 4-39 P m - Next Friday, 4.34 p.m*