MANGERE SPEEDWAY.

New Zealand Herald, Volume LXV, Issue 20130, 15 December 1928, Page 12 (Supplement)

MANGERE SPEEDWAY.

DIRT TRACK FORMED. Good progress is being nyide on Mr. G. Henning's dirt track at Mangere, and there would be no obstacle to a race meeting within a few weeks, although it is not proposed that the opening meeting should be * held until February or March. Many who viewed the speedway site three months ago expressed doubts when Mr. Henning estimated that the track would be available early in the now year, but the scheme has now taken very doßnito shape. The surface is naturally still rough in places, but the 1£ mile circuit has been formed and to demonstrate the stage which formation has reached Mr. Henning drove a car around the track last Saturday. There is some speculation regarding the date on which the first speed performance will be possiblo and various tests will, no doubt, be made after Christmas. The racing committee is naturally watching progress closely and a wager for £lO has resulted. Mr. Henning estimated that the track would hold touring speeds before the end of the year and the wager will probably bo decided on December 25, the requirement being that a car should cover the 1£ mile lap in two minutes, or maintain an average speed of about 37 m.p.h. As a result of the wager the provident fund for employees of the A.A.A. shall benefit to the extent of £lO whichever way the test goes. Mr. Henning has put great energy into tho preparation and supervision of the speedway and if enthusiasm can achieve anything Auckland motorists will make the acquaintance shortly of a sport which which will offor ample thrills.

VALUE OP A LITRE. Tho question is sometimes asked by motorists—what fraction of horse-power does the litre equal ? The term " litre " as applied to many European sports cars is really a measurement of engine capacity and cannot bo expressed in terms of horse-power whero a multi-cylinder engine is concerned. In connection with motorcycle engine 100 c.c. (i.e., one-tenth of a litre) is sometimes regarded as representing 1 h.p., as, for example, a 175 c.c. engine is designated 1$ h.p. A car engine of, say, 10 h.p. is sometimes termed 1 litre," a 15 h.p. engine 1£ litre, and a 20 h.p., 2 litre and so on. A good way of calculating the cubic capacity of an engine is to obtain the diameter of one of the cylinders in centimetres (there are 10 mm. in a centimetre), square it, multiply by .7854, which is a constant, and multiply the result by the length of tho stroke (also in centimetres). This is for a single-cylinder, so that for a multi-cylinder engine you would have to multiply by the number of cylinders. TARRED COACHWORK. Sand has been spread on a section of tarred surface in Symonds Street apparently to prevent the nuisance of tar splashing during the hot weather. Some tar sprayed surfaces in Auckland have already begun to " weep " and unless tho motorist is careful the paintwork Tarred roads in parts of Australia become almost spongy in summer and it is fortunate that roads are not affected to tho same extent in New 'Zealand.

Some drivers do not care how fast they drive over freshly tarred roads, and they forget that the modern type of tyre in good condition naturally tends to pick up loose tnrrod pebbles, as well as gouts of liquid tar, and cast them in such a* fashion that any passing vehicle is bound to- be bespattered unless the two machines arc proceeding slowly and in strictly parrallel courses. Deflection involves bespattering. There are various preparations for taking off tar, but it is better to avoid the necessity of using them. If one has nothing else available, the best thing to do is to spread butter over a tarred part at the end of a run and to leave it overnight on the spot?. It -should be possible to remove the tar in the morning.