CYCLING AND MOTORING.

Northern Advocate, 30 January 1922, Page 3

CYCLING AND MOTORING.

VACUUM TUBE IGNITION

ADVANTAGES CLAIMED

Increasing attention has of late Been paid to the claims of the ignition coil, cither as the sole moans of ignition or in conjunction with the magneto. At the recent Motor Show at Olympia (England) some firms adopted the dual form, and it would appear that the present time is a transition stage.

Coil ignition has, of course, much to recommend it; first, from the fact that cach cylinder is rendered independent of the others, and secondly because it is more economic than the magneto. It has, however, always laboured under the disadvantage that the platinum contacting points do not endure for any considerable period without attention, ■and further, once they cease to pass current and require filing the period for which they will endure is shortened, and in any but expert hands they cease to function.

But for this difficulty the magneto would probably have never proved such a serious competitor to the induction coil for the purpose of igniting the charge in internal combustion engines, and could a method have been devised whereby the interrupter would have produced a secondary spark far an indefinitely long period of time without any failure of the make-and-brea.c apparatus, the induction coil woulu have bec-n a perfect instrument; and thfl more so, as the character of the secondary spark from the induction coil is much more satisfactory in regard to its length «ind intensity than that pro* duced by the magneto.

Herr Bosch, the inventor of the magneto bearing his name, is reported to have stated that, in his opinion, the magneto had but a few years more in which to disappear, and his prediction would appear to be well grounded m view of the fact that a method has ben discovered by Mr E. C. Perrem, a stu .- ent of Trinity College, Dublin, by means of which the contacts used in the make-and-break device will endure for an indefinitely long period, the total length of which has not yet been discovered, but which can reasonably be put at as long as a normal car will run. This device may be briefly stated as one which encloses a make-and-bfeak in vacuo. The vacuum tube containing it will be in practice about 2J inches long by about half-an-inch in diameter, and will rest immediately above the core of the induction coil. It w« ? i, moreover, be fixed in position by an automatic clutch, and can be removed 01 put in position in a few seconds. With the make-and-break device working in vacuo it has been found that platinum need not be used for the contacts, but that a cheap metal will function perfectly. Tor the past eighteen r.-onths exhaustive bench tests have

been curried out, and the results Vive shown that without any attention whatever the tube will endure for 100 hours. At this point, however, the test was stopped, and an examination of the contacts clearly showed that their life ir.ight be put at half as long again. It is not sought, however, to lay any emphasis on this point. It may, however, be said that the, character of the sscondary effect seemed to be distinctly above that which would have been obtained from a magneto or by a make-and-break device operating in air. Moreover, the secondary spark obtained was much greater in intensity and length than that obtained by either of the two methods, having regard to tho amount of current passing. It is somewhat difficult to correlate the significance of the above bench test with its equivalent in car miles. If, however, it be assumed that the ratio; is 20:1 and an average car rate per hour of 20 miles, it would follow that 100 x 20 x 20 would equal 40,000 miles. It must also be borne in mind that the 100 hours referred to did not represent the possibilities of the tube. It is not thought necessary to draw attention to higher ratios which would te established as to the duration of the contacts when functioning in vacuo as compared with pure platinum points in air. It is felt that the figures adopted could with reasons be stated much higher in .terms of ear miles. They speak for themselves, however, as far as this new method is concerned for a reversion to the coil form of ignition. In conclusion, the advantages which would accrue from the employment of the vacuum tube for ignition purposes for internal combustion engines, whether for cars or stationary engines, may be summarised as follows: (1) An extraordinarily long life, which woi 1g appear to be as long or even longer than a normal car will run.(2) Once fixed in position it would require no attention whatever. (3) Easy starting of the engine, as the tube would give an ample spark, even at two volts. (4) It co-iU be adapted to all the coil boxes a - present in use. (5) The tube could be put into or removed from its clutch in a few seconds.

BICYCLE UTILITY In view of the prices that are now ruling for bicycles, and which are rapidly approaching pre-war figures, the question naturally arises whether the time has not arrived when a general attempt should be made to bring about a large increase in the number of users of cycles. It has been stated time? without number that the bicvclc still forms the cheapest form of rapid locomotion, and in these times of high cost of living, increased railway fares, etc., the advantages attached to the use of the bicycle have been greatly overlooked. The present day machine, ra-

tionally geared, affords an easy means of getting about, at a running cost — after the initial purchase—of only a few shillings a year for tyre upkeep. The life of a bicycle is a matter of many years and tens of thousands of miles and the advantages .that accrue from its use are out of all proportion to the cost of owning and using a bicycle. It certainly stands by itself as the most economical vehicle of utility, and the many uses it can be put to for either business, social, or sporting purposes should render the bicycle more popular in this country than it is. AN ECONOMICAL MACHINE That an effort is being made to market a motor cycle, within the reach of those who cannot afford £100 or tho test part of it for a solo machine, was evidenced by several exhibits at the rceent motor cycle show at Olympia, London. One machine was listed at £27 6s Od, and a very serviceable outfit it looks from the illustrations and details given in the English Press. The weight of the machine is only 751bs, the power unit being a two-stroke, single-cylinder engine, with a bore and stroke of 60 millimeters. The frame is so designed that either sex can ride the machine, which is said to be a really reliable proposition, built on lines that will appeal to those desirous of motoring at » reasonable speed and low-running costs.