Rumblings, October 1931

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Pumblin Nqs

k P39 130 UERGES

Shelsley Reflections.

ALTHOUGH a wet day for S hel sl e y was a disappointment to those who wanted to see records broken, it had compensations, as it gives much food for thought in the matter of controllability. Especially in the latter part of the afternoon, the surface became very slippery and many cars found considerable difficulty in keeping on the toad.

In the matter of skids and their correction we had plenty of example of the advantage of high-geared steering when holding a car which was sliding about. The Bugattis and Frazer-Nashes were, as usual, particularly quick in correction. A more interesting problem, and one which is much harder to solve, is the matter of getting all the available power transferred effectively to the road. Power-weight ratios have now so increased that cars like the “Terror,” and the Villiers have definitely got more power in hand them they can use all the time, and the slippery conditions accentuated this and put many other of the faster cars in the same plight.

Mays seemed to suffer less from wheel spin than the lighter stuff, as the heavier car managed to bite through the grease and obtain some sort of a grip. Even so he was compelled to ” blip ” in and out all the way up owing to the grip being insufficient to transmit all the horses which Amherst Villiers had extracted from the motor. The accepted method of increasing grip these days seems to be twin rear tyres. This certainly does the trick up to a point, but it also introduces other snags. For one thing the weight immediately goes up, but as this is over the part required to grip

it does not so much matter. Another point is that the extra grip is in itself a doubtful advantage on corners, as it means that the balance and weight distribution which was correct with single tyres and less grip may now be quite wrong.

If a car is to be safe on corners it must be arranged that the front wheels will still grip after the rear ones have started to slide. If the grip of the rear is increased without a corresponding alteration to the front this state of affairs may be reversed, and those of us who have experienced the helpless sensation of going straight on with the front wheels on a lock, will need no further confirmation of the unpleasantness of it.

Front3wheel:skids.

When the road becomes greasy these points are brought out in a much more definite way than when dry, and Nash had quite a nasty moment on his second run when his front wheels had a momentary lapse and ceased to control the direction of the motor. Now a standard FrazerNash definitely doesn’t do that sort of thing, so that is one example of the difficulties which follow on increasing the grip of the rear.

Leaving the tyres as they are and increasing the weight on the back is another method, and the same dire results crop up and the front wheels cease to adhere as they simply have not enough load to make them do so. Then again there are cases of cars when the weight of engine, etc., is too much over the front axle, and they also suffer from the front wheels going sideways. It is all very difficult, and the result is bound to be a compromise as cars are built at

present, and it is not always easy to see just why one car is so much better on corners than another. The Bugatti is a shining example of how a car should behave on corners, but by the time a maker has won a few Targa Florios he is likely to know something about such matters, and M. Ettore Bugatti can hardly be expected to publish a booklet on “How to make a car behave,” for the benefit of those who haven’t taken the trouble to find out.

The proportion of weight on each axle has a lot to do with it, of course, but the positions and concentration of the weights has even more. In other words a car with the weight almost entirely concentrated at a point near the centre of the chassis may have the same axle loadings as one with the weights very nearly over the axles, but they will control very differently. The latter type has a far greater moment of inertia about the centre, will be much harder to deflect from a straight course, and what is even more disconcerting will be very hard to straighten up again once it has started gyrating.

This was the trouble with the big twin-engined Sunbeam with which Segrave did 203 m.p.h. The big masses at the ends gave the car a heavy pendulum effect which was difficult to control.

All this seems to be getting away from Shelsley Walsh a trifle, but here the problem is in a way similar, as even if you can make your wheels grip, you must also have control on corners, and this event gave a good illustration of the limitations of a normal design with a lot of power. People suggest front wheel drive, but here the wheel-spin problem is even worse, and we then come to

four-wheel drive. The grip then should be adequate for almost anything, but it would require a lot of cunning machinery all over the vehicle. It would also weigh a great deal more than the normal arrangement so that the power would have to be increased to cope with it, though as the present difficulty is concerned rather with adhesion than with obtaining power, this would not be of such vital importance.

4 W. D.

Another thing from the driver’s point of view is the difficulty of getting really good steering when the steering wheels are also being driven.

I have only had experience of driving two different makes of front wheel driven sports cars, but they each gave me the impression of being lifeless in the steering. Normal caster action cannot be arranged, owing to the fact that the wheels are being sometimes driven and sometimes not, and the caster arrangement has to be opposite for each case. Therefore, the problem is solved by having no caster at all, and although the result is positive it has not such a good “feel,” as a well arranged normal steering.

When all these things are considered and gone into, the fact remains that the record is 42 2/5 secs., and that Von Stuck drove a perfectly normal looking single seater racing car without even twin rear tyres, and we then come back to where we started, always with the reservation that Von Stuck has done this sort of thing before. In fact no English driver can get the general experience of hill-climb work which is gathered by those drivers who follow the events of the European championship, and this may be a slight handicap, but even so, we should have sufficient special experience of ” our ” hill to make up for this. Moreover the visit of Zanelli and Tort showed that we can beat almost everyone at Shelsley. The search for suitable hills on private estates still goes on among enthusiasts but it is no easy task, and the combination of a suitable private road and an owner who is willing to let it be used is very, very rare. One of the best actual hills that has been used recently is Craigantlet, in Ireland. Readers

will remember that the last affair there was the week before the Ulster T.T., when Nash and the ” Terror ” put up such a fine show and knocked 9 secs. off the previous record.

I was talking it over with him shortly after the event, and he was delighted with the hill itself. To start with it is roughly twice the length of Shelsley Walsh and has two perfectly good sets of S-bends in addition to the usual variations. The first time he saw the hill was when some local enthusiast took him out there in some not-too-new touring car, and he said the hill seemed about five miles long. Naturally it seemed a bit shorter in the Terror, but it is a real climb all the same.

The Everpresent “Movie.”

A thing which has struck me particularly of late is the great increase of amateur cinema operators at all the main motoring events, and with the great improvements recently in the available apparatus there is no better way of keeping a personal record of the season’s motoring.

I was chatting about this “movie” business the other day with a friend, after seeing his excellent films of the Ulster, the Open Shelsley, and one or two Brooklands meetings.

He was very much in favour of starting on a simple apparatus with the 9.5 mm. film and going on to the 16 mm. and more gadgets after a year’s practice.

For anyone with a good experience of photography already, and especially speed photos, this would not be necessary, but otherwise it is a good plan as the small films are very much cheaper and there are less things to do wrongly. Of course the modern Kodak, Bell-Howell, and similar cameras are amazingly cunning bits of work, but although as fool proof as possible, they require careful use and some practice to get really first class results on difficult subjects, and a little study will be amply repaid, as my friend’s excellent collection proved. I should think Donald Healey must have one of the finest collections of private films of motor events, for he takes his camera everywhere he goes, and as he seems to motor over the whole of Europe about once a month, that ” everywhere “

is wider than most motorists can achieve.

More Riley Records.

The Riley company are staunch supporters of the ” unblown ” engine for sports cars, and there is no doubt that for really scientific development of valve gear and cylinder head design, this type is essential. Also they seem to find no difficulty in annexing copious class records without the aid of any blower.

Following his successful attack on the 50 and 100 miles records recently, George Eyston has been knocking the 500 mile record about to the tune of 104 m.p.h. which looks as if Rileys really mean business in. the 500 miles race on October 3rd.

A remarkable thing about Eyston’s record-breaking is that he never seems to get a peaceful run without something trying to upset things. A month ago he had a tyre go when all out and spun round a turn or so, while in the 500 mile ” do ” he had his work cut out to avoid a motorcycle which elected to run into another car almost in front of him. No doubt he is quite used to this sort of thing by now, but the ordinary motorist might find it a little trying.

A Veteran in China.

The story of the young couple who bought a very ancient Rolls-Royce for £20 and exchanged it with the Rolls-Royce people for a brand new 1931 model, has long been scotched, but another story almost as good— and true this time—comes from China.

A Mr. Rasmussen discovered a very ancient and decrepit RollsRoyce in a Chinese junk shop in Tientsin. Mr. Rasmussen bought the car for somewhere in the region of 250, just because he hated to see it lying dirty and neglected. He took it to a local motor mechanic, and had it stripped to the last bolt. Everything was perfect, except for one broken piston ring. The car was put together again and groomed, and on its first day on the road, Mr. Rasmussen did 35 m.p.h. at a touch of the accelerator. Once it is re-run, in, Mr. Rasmussen is taking it for an extensive trip into Mongolia. This car may well end up in a museum.

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