I received my copy of MOTOR SPORT for December to-day, and was very pleased to see, on page 30, about your new date of publication.
I always look forward to the paper and should have been extremely sorry if anything had happened to prevent its further publication. Wishing you all success, I am, yours etc.,
W. S. Orr. Sir,
Having read the article ” On the Trend of Sports-Car Design ” I am interested in the book referred to (” Economics of Carburetting and Manifolding “). Is it still obtainable ?
May I take this chance of congratulating you upon the ” make-up ‘ of MOTOR SPORT and also the new date of publication.
Could you in the future give some hints on tuning the Hornet Special, in particular the 1934 model ? I am, yours etc.,
Derby. NORMAN B. SCOTT. THE TREND OF SPORTS-CAR DESIGN” Sirs,
Having read the article on “The Trend of Sports-Car Design ” we feel that although this article contains a favourable comment re Centric Superchargers, there are one or two points made in the article which we consider rather misleading to the general public and which we should very much like to see straightened out. Perhaps you will permit us to respectfully point these out. In that portion of the article where the Writer d i sr lISSC3 superchargers, he makes the remark that ” we have only the racing high pressure system to boost up power at peak crankshaft speeds and proprietary systems operating inefficiently at pressures of a few pounds per Square nch.” Now this is hardly the case ; the supercharger installations carried out by this firm are most efficient in operation, and although in most cases we arrange for the maximum pressure not to exceed 5 to 7 pounds per square inch, this boost pressure gives an increase in B.H.P.. of approximately 36 to 40 per cent., from which it will be seen that, far from being inefficient, this system in conjunction with a Centric supercharger is most efficient, Mention is made in the article of the twin Centric supercharged Frazer-Nash and the supercharged Rapier. Whilst Frazer-Nash use fairly high pressure, in the case of the Rapier, a Centric super
charger is used operating at a pressure of approximately 7 pounds per square inch, and the remarkable performance of this car again proves the efficiency of the system.
With reference to the Bro ugh Superior we should like to point out that this car, contrary to the description given in the article, does not use a centrifugal type supercharger, but is fitted with a Centric Supercharger operating between the carburetter and the engine.
You will see from the enclosed curves of a well-known proprietary engine used in a popular make of car the improvement gained by supercharging, and the fuel consumption curves are indicative of the high efficiency obtained. We am, yours etc.,
CENTRIC SI’PERCHAROERS LTD. Bow Lane,
Fishergate Hill, Preston, Lancs.
NoTE.—We agree that certain proprietary layouts have been produced which give quite high manifold pressures, but it is still possible that when such pressures are applied to the average production engine it is desirable to modify valves, pistons, and gaskets to ensure absolute reliability, which increases the cost of Conversion.
Our contributor paid tribute to the 30 m.p.g. fuel consumption obtained from an M.G. Midget effectively supercharged with a Centric installation. We apologise for the error in connection with the type of supercharger used in the Brough-Superior, which is a Centric compressor driven by triple belts.
The author informs us that the fourth centrifugal-booster exponent that he had in mind was, in fact, Duesenberg—Ed. A SUNBEAM ENTHUSIAST Sirs,
Having read your article “Testing a Second-Hander” in the December issue of MOTOR SPORT and your constant references to the inexhaustible qualities and charms of those three noble old makes, the 3-litre Bentley, the 30/98 O.E. Vauxhall and the 3-litre Sunbeam, I feel I cannot let the oceasion pass without some comment and further compliments to these old cars.
As an owner of a 3-litre Sunbeam, and in the past, an Invicta, both being purchased under three figures I consider myself entitled to write a few words. The Sunbeam is a 1926 model. It has admittedly only 24,870 miles to its credit, having once been the property of a wealthy gentleman whose stable included four
other cars. For some reason it lay in its garage for six and a half years with every plated part heavily coated with vaseline. When I purchased it I had fears that I should never •start it in the winter months as it is practically impossible to pull the engine over compression when cold and even worse when hot. Since then I have had reason to dispel all doubts about such fears. Even when left a week in a dampish extremely :airy garage it will fire upon the first depression of the starter. The same happens even
under ice-cold weather. Its top speed is about eighty and will clock sixty-five in third, whilst its acceleration is well in excess of many modern so-called sportscars of equal or more horse-power.
On a long journey the petrol consumption works out as far as I am able to judge by gauge readings and trip measurements at just 24 m.p.g. Oil is about 12-1500 but this is only a rough figure.
And now about maintenance. Every vital part is thoroughly accessible and being an impoverished owner I do all minor adjustments myself. Up till now I have only had greasing to do because the engine seems to run without attention, not even a plug has given trouble. And so was the Invicta. Always
started instantly ; consumed one gallon of petrol for each twenty miles and required merely one de-coke during the twelve months I owned it. That was a 1927 model. The same too with an Alvista model Alvis. This was a 1927 model. a
by the trade as a sticky model. et it merely cost 10/for repairs in nine or ten months, one being valve adjustment, the other a steering adjustment. In the summer of 1935 I was invited to try an O.E. 30/98, and it was only the contemplation of an expensive cruise which changed my mind about buying it. In a trial run this car clocked 90 m.p.h. This was I believe a 1924 or 1925 model, and when I tried it it was as tight as a
drum with tremendous life. All the transmission points, engine and gearbox, were externally dry, yet this car had, even the vendor admitted, 82,000 miles to its life. I fear that I mimed a lot of real motoring when I refused a not altogether disappointed owner the chance to buy this fine old car.
I have discoursed at great length and conveyed nothing much more than I very much admire the old classical type of slow-revving car and advise the purchase of one of these type in preference to these little buzz-boxes which seem to be rusting themselves to an early extinction.
In conclusion I wish MOTOR SPORT every success in the New Year. I am, yours etc.,
L. F. S.
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