OPINIONS and Q UERIES
Page 32
If you've noticed an error in this article please click here to report it so we can fix it.
THE P.S.V. INDUSTRY'S 'CONTRIBUTION TO TYRE LIFE WAVING read with considerable interest the excellent "articles on tyre life by " LAT B.," I would like to say that I agree wholeheartedly with him.
As I travel very frequently by bus, .I think that this form of road transport needs special attention with regard to tyre conservation. Expert and thoughtful co-operation between drivers and the operator is essential.
I will try to illustrate my meaning with the case of two. men:— Driver X is conscientious. He drives with care, brakes his vehicle gently, treats the tyres with consideration.
Driver Y, on the other hand, drives fast, jams on the brakes, and ruins the tyres rapidly. He is .driving a vehicle belonging to a company, or a municipality, as the case may be. It is not his own vehicle, his " boss" buys the tyres, so why should he worry.
The latter type of man is apparent, unfortunately, in some staffs, but, from my own observations, it has decreased considerably in the past six months or so. The average P.S.V. driver takes an interest in his branch of this so very important war work.
Closer co-operation between management and drivers would, in my opinion, reduce driver Y cases to a minimum, if not stamp them out.
Make it clear to the drivers that they are as much concern,ed with the conservation of rubber as any branch of the Forces. Drive this home to them and I think
that the P.S.V. industry will rank very -highiy in the
saving of rubber. KENNETH SMITH. • Cheadle Hulme.
MORE ON NON-CYLINDRICAL PISTONS
THERE were plenty of reasons put forward why the flat-piston engine would not work; the mentality behind the reasons was weighed up and the experiment went forward. Tests carried out over 5,000 miles showed that there was no piston-ring problem, neither was there unequal thermal expansion.
The engine was made of equal volumetric capacity to the standard product, and no different performance was observed between them. The motorcycle was ridden by riders who did not know until afterwards that the engine was non-standard; its appearance did not suggest any diffecence. Several people rode it, and were never told that the machine was not standard.
The cause of cylinder wear has never been con vincingly proved. It is much more likely to be connected with the rough surfaces of piston and cylinder, finished according to to-day's methods of machining, than to any of the various mechanical, chemical and thermal explanations put forward at different times.
A .reamed cylinder surface finish is of the order of 26 microinches, and that of a piston 35 microinches; as produced by the new super-finish methods, these figures of roughness of finish are reduced to 4 and 6
microinches, respectively. AZOTE. London, W.14.