MOTOR AND CYCLE.

Taranaki Daily News, 30 October 1917, Page 7

MOTOR AND CYCLE.

NEWS AND NOTES,

A favorite recommendation in selling a car is that it will pick up speed very rapidly; but it would seem that both dealers and manufacturers are working against their own interests in suggesting such methods of operation to users of ears. To accelerate a car weighing over a ton from five miles an hour to forty miles in fifteen or twenty seconds means a tremendous Rtrain on every portion of tho machine, with consequent rapid deterioration, and is especially destructive of tyres. Moreover, there is no reasonable advantage in the procedure, for the time gained thereby could hardly be measured witli a stop watch in. ft day's run. The result is attained by supplying a much greater power result than the user has need for., It also means that the car owner pays for a lot of petrol consumed by the excessively large engine, which has been of no benefit to him.

The war has hepled to awaken the world to the necessity for performing heavy farm work by motor tractors, and the automobile engineer has taken up the proposition with enthusiasm. Some of them say it is a simple problem, while others think it will take ten years to I produce a satisfactory machine. Both would seem to be wrong, for they are apparently unaware of the great amount of work-that has been done in this direc-' tion by makers of agricultural machinery. When the automobile engineer took up motor trucks, relying entirely on his previous experience, he thought it a simple problem, and with great confidence put his light pleasure car engine into a truck chassis. The result was a disastrous failure that has required many years to eliminate from the public mind. The truck was a special problem, requiring a careful study of entirely new and different conditions, and the farm tractor is in the same class. Steam tractors have been built for at least forty years, and many people have struggled with the problem of applying the internal combifstion motor to the same work. It is to be hoped that those now undertaking the industry will make a careful study of past efforts and not burden the public with immature experiments.

In view of the influence which aviation is bringing to bear upon engine design, the question has arisen as to whether the jair-cooled engine will enter into motor-car practice. There is no reason win- it should not bo embraced for this duty, although it may be averred that aeroplane and motor-ear conditions are va.itly dissimilar. In the former instance the engine is invariably working at a constant load—its maximum—ami that the draught set up is conducive to efficient cooling. On the other hand, the motor-car, particularly in inter-urban service, is operating under adverse circumstances, especially in traffic, and this must contribute to' the risk of overheating. But against this argument must be pitted the experience of a wellknown American car, w v hlch has some striking performances to its credit, such as tans-continental runs involving the negotiation of the Nevada desert with the thermometer hovering in the vicinity of 110 degrees, and itN low-gear run from Chicago to New York, a matter of 800 odd miles. In neither instance was the slightest overheating- experienced. The crux of this hinges upon the facilities for collecting the induced draught of air and 90 distributing it as to bring it to bear evenly upon the whole superficies of the cylinder. In so far as the aero engine is concerned, the introduction of a cowl .over the cylinders serves to ensure the maximum cooling effect to be directed upon the fins of the cylinder although we might mention that complete success in this direction has not yet been achieved, the distribution of the cooling air being far more equitable. "But," ft will be maintained, "it is impossible to secure with the motor-car a draught of comparative velocity 1 to that incidental to an aeroplane travelling at 90 miles an hour." Yet all aeroplanes do not reach such a speed. Some have a bare maximum of 30 per hour. Speed depends upon the duty for which they have been specially designed. Still, allowing that th e normal speed upon the" high road can never approximate that attained in the air, it is .possible to supplant the natural induced draught by artificial agency. Everything turns upon the design of the fan, its speed, and, last but not least, its precise position in relation to the engine to ensure the maximum cooling efficiency. The perfection of a reliable air-cooled engine for motor-car practice is certain to exercise a far-reaching influence in all (directions It enables an appreciable saving in weight to be obtained, removes a serious worry from the motorist's mind, and appreciably simplifies the engine, inasmuch at is eliminates about 300 individual parts! The suggestion of a 16-20 h.p. ear being equipped with aircooled engines replete with an efficient fan system may seem fantastic in the light of current popular knowledge. But certain British manufacturers are preserving an open mind. The aero engine is destined to bring about a modification of many prevailing ideas, and it is quite possible that air-cooled motor-car engines may be one of them.

the aluminium piston alloy is from ten jfo fourteen times that of iron and reflects itself in a, marked decrease in the j air/unt of carbon deposited on the piston head. Under favorable lubricating conditions there may be a total absence of carbon. In engines with the smaller bores this thermal property may be, used to increase the compression beyond ' the point at which pre-ignition would Invariably occur with iron pistons. The hardness of some of the aluminium alloys, lignite, for example, falls not far short of that of the average piston iron. At the same time, it is sufficiently softer j than the iron or semi-steel of the cylinder, that in the event of piston seizure, the piston and not the cylinder is scored. A lecturer on aluminium recently stated: "The aluminium piston has come, and has come to say. Any trouble existing has been in the nature of 'growing pains.'" It_ has been found that it is not yet /wise to attempt to carry weight saving |to the limit. In other words, engineers should be satisfied in cutting the weight pf an iron piston in half instead of following the exact design of the latter in order to avail themselves of the two-| thirds saving in weight. Aluminium can ' be machined nearly twice as fast as tast iron. This means a saving in tinv, j cost, floor space, and machinery. Wh n the market is normal, considering initW costs, casting for casting, it is claimed that it will be cheaper to use aluminium' than iron. It has been stated thi><;. n set of aluminium pistons was used .o- : [IB,OOO miles, and showed an avur.rp wear of le.«s than a quarter of a tlicj.andth of an inch. The speed of t)ie engine was 1,300 r.p.m., and the aiuwmium pistons were counterparts of t.'ia ! iron pistons that they displaced.-