THE MOTOR

Evening Post, Volume XC, Issue 63, 11 September 1915, Page 12

THE MOTOR

SIGNS OF THE TIMES. SECONDHAND OARS. Perhaps the most notable feature of the British motoring journals in recent months is the devotion of a great deal of space to the subject of second-hand cars. Pages are devoted to the matter, and some ofe the papers contain catalogues of second-hand automobiles available for purchase. On© good feature of this deliberate policy of fostering the exchange of ownership of cars is that it tends to help the British manufacturer. The intending purchaser who buys a good machine from somebody who can no longer maintain the machine or who prefere to do without it is in many cases avoiding the alternative of buying a foreign-made car; and the efforts of the British manufacturer and the British trader are being honestly directed to checking foreign purchases as far as possible. One of the things most to be desired now is the reduction by British countries of imports from other nations. To _ keep purchasing power within the nation is a form of national economy closely allied to direct individual economy. To a large extent, no doubt, the same principle can be applied here. There are for instance many men who are going to the front and have motorcycles for sale; and it is certainly desirable in more than one respect that intending buyers should take over such machines than buy a new one which gives the foreign manufacturer a firmer hold upon the New Zealand market to the future detriment of the British trade when it revives. ■ THE PUNCTURE-PROOF TIRE. Fallacies certainly die hard, and ono of these, says "H.T." in The Motor, is that the pneumatic tire is, even in these advanced days, a most vulnerable object for the puncture fiend to attack. With this fallacy ever before them, inventors still exercise their ingenuity, and, as a result, a puncture-proof tire would appear to be invented on the average about once a week, and, apparently, so long as the use of compressed air form* the basic principle of the pneumatic tira, inventors will continue to produce what is, in their opinion, the one and only perfect non-puncturing tire, which, nevertheless, usually fails to" displace' the ordinary standard tire. What the average inventor of these tires fails to realise is that the steady improvement in the pneumatic tire which has been in progress for ten years has, in effect, rendered actual puncture troubles negligible under fair conditions of tire usage. This assumes that the tire used is of a size and quality equal to work expected of it. If a tire be overlooked, it will be j prone to puncture, if nothing worse happens, although even in this case the risk is nothing greater than a sporting one, as the users of numerous undertired care must be aware of. It is difficult to estimate what propor-. tion of tire troubles to-d&y are due to actual penetration of the tube by the two commonest forms of puncturing medium met with, namely, nails and flints; but it can hardly' be an appreciable figure, such as it was in the old days. It would probably be found that the vast majority of such troubles as are actually due to direct injury to the tube are traceable to carelessness in fitting the tube, which results in nips and bursts, and, so long as an air tube must be used, it seems impossible to make it proof against careless usage and neglect. With an ample thickness of rubber on the tread of the cover, it must be admitted that, for all-round practical purposes, the modern cover is punctureproof. This means that, on the average, about 2500 miles should be covered before the exceptional puncture, as from a long nail penetrating the cover sideways, occur*. The aim" of the tire makers for years past has not been in the direction of i following the "will-o'-the-wisp" of abso- | lute punoture-proofness, but in improving the durability, resiliency, and nonskidding properties of the coyer. There are numerous ways of making a tire actually impenetrable, and these have been known to the tire trade for many ' yeans and exhaustively experimented with. From the fact that none of these ■ expedients has been permanently adopt- ! Ed, it can, be reasonably inferred that either they are superfluous or create disi advantages which nullify the benefits obtained. The typical inventor who thinks that the world is 'gasping for a ptmctureproof tire simply ignores the vitallyimportant questions of resiliency and efficient air cushioning, and would seem to be obsessed with the idea that it is | only necessary to bury the air chamber deep down in the bed of * rim and. pile up layers of rubber and metal over it ; till the air chamber, such as it is, is protected out of existence. ELECTRIC, TRANSMISSION. ■ The petrol motor, says a witter in an English journal, has many virtues, and | one grave fault. "Its. power-for-weight factor is higher than, that of any other prime mover, and it burns a, compact and easily-handled fuel. But it lacks absolutely the quality that is variously called " flexibility," "docility," and so on — the ability to adapt its power output to varying forms of load. Before the petrol, engine can claim ; ideal flexibility, it must first acquire the ability to increase the power of its in- j dividnal piston strokes as their number becomes less. The more efficient the petrol motor becomes on its present lines the more, strikingly absent will be this ability to' deal with a load equally well at varying speeds. The more the' designer develops in his engine the cardinal virtue of great power for small size and light weight, the nearer will he get to evolving an engine that will run at one speed only. It is some years now since we heard of the "gearless" car. Except in the case of transatlantic vehicles with large and ".fluffy" engines, the tendency is strongly towards more, rather than less, speed changes. • There is also a very marked diminution in the one-time popular slogan of " everything on top gear," and this is all to the good, for, obviously, the " everything-on-top " car must have either too large an engine or too low a gear ratio. Of all engines the electric motor fulfils most perfectly the requirements of flexibility in the true sense of that 'muchtwisted word. It is absolutely opposed to the petrol engine in this respect — it gives the greatest effort at its slowest speed, and as its rate of r.p.m. rises the consumption of current automatically falls. It is, in fact, ideal from the point of view of "everything on top," and it is not surprising that its combination with the petrol motor has proved so highly satisfactory in the case principally of the heavier vehicles. For railway work, where a unit often gives several hundred horse-power, it has been most successful. Is there, then, any reason why it should not prove equally valuable for the pleasure vehicle? A "little time back the idea, would have seemed unlikely ; now it appears almost certain. For electricity has already insinuated itself far into the economy of the present-day car. We began with accumulators and coil, superseded later on by the magneto. Now electric lighting and starting are rapidly becoming standard, so that the time is swiftly approaching when every car will have its starting motor, charging dynamo, and accumulators. Therefore, the question of the drawback of added complication docs not arise. SPLENDID WAR WORK.

revealed at the annual general meeting of the British Automobile Association and Motor Union in July. The' report, ■which was adopted on the proposition of the chairman, Mr. W. Joynson Hicks, M.P., showed that all able-bodied employees had joined His Majesty's Forces, and the authorities, recognising the value of the Automobile Association patrols and their unique experience, sanctioned the formation of two special companies, to be attached to the Bth Battalion (Cyclists) of the Essex Regiment, under the lead of the secretary (Captain Stenson Cooke). A great amount of work had been done in transporting the wounded, and for a considerable period the whole of the cars required to meet the wounded at the Londoiic. railway termini were those of Automobile Association members. Similar assistance has been, and is still being, given in various large towns. , j More than 120 motor ambulances have .been" presented to our Allies; 150 cars have been lent by members to the various commands for the use of staff officers, and at the request of the authorities the association has formed, a transport section to the Headquarters Central Detachment of Special Constabulary. As the result of a number of economies^ there is a surplus of £30,000 on the year's transactions and since the account* were made up some £23,000 or £24,000 has been invested in the War Loan, while the -Consols which had been held for some years have also been converted. THE MERCEDES MYTH. Not long ago it was reported in aoma of the English papers (and cabled to New .Zealand) that Mercedes cars (built m Germany) had four noles, for which there seemed to be no use, in the after part, of the. chassis. These holes, it waa alleged, had been found to be intended for the bolting on of a machine gun. The story had all the air of a far-fetched piece of imagination, and it was not long before it was exploded. But one investigator found something more to go on. Writing "from somewhere in France" about the subject in an English paper, he said "perhaps owners who have been puzzled by the holes in the chassis have also wondered why the Mercedes are fitted with a cut-out, a flat fan belt, a, very extensive and unnecessarily strong brass air heating jacket, an unusually intricate carburetter, water-cooled footbrake, etc. At any rate, the other day I was teized with a violent fit of curiosity, and took down all these parts, as well as the magneto, and, not being a very good mechanic, I was somewhat at a loss to put the pieces together properly. Imagine my surprise, however, when I had at last finished my selfallotted task, to find that, instead of a carburetter, a magneto, an exhaust pipe, fan belt, etc., with which I had started, a real live machine gun now stared me m the face. Of course, now that I have found out what these four holes in the chassis are for,. I find that the gun fits on to tbe frame like the proverbial glove." '