The Subtle Art of Fast Cornering
IT IS A curious facet of the human race that among quite a number of its younger generation there exists an almost fanatical desire to be able to drive a motor car round a difficult corner faster than their fellow beings. This competitive urge, when not fulfilled, can cause much distress and anguish. I experienced this motivation myself, but early came to realise that I was not cast in the mould of racing driver. A racing motorist, maybe, had opportunity arisen, but that is another matter.
I think fast cornering can be termed a subtle art, for at racing level it is measured in hundredths of a second of time and, overdone, can result in fatal injury. The rather astonishing thing is that although rapid cornering is mostly what motor racing is about, and mainly how races are won, especially over the short circuits we have in Britain and elsewhere, and in spite of the fact that most enthusiastic drivers with a fast car under their control and a twisting road stretching away ahead of them respond by seeing how quickly they can corner, it was a surprisingly long time before this aspect of motoring was properly understood and the equations and concepts associated with it freely discussed. This becomes apparent if we study some of the reports of ancient motor races. Charles Jarrott, in the first book devoted to the sport, his great “Ten Years of Motors and Motor Racing”, published in 1906, recognises the great challenge and thrill of handling a racing car—”In addition to the excitement of driving a new and practically untried machine . . . here is your opportunity to prove your worth, to prove your superiority over your competitors; there is no circular course on which you can practise and study every little curve and corner months before the race. The long winding road stretches before you, reaching from the capital of one great country to the centre of another. Hundreds of miles of straight road, narrow road, right-angled corners, treacherous turns, maybe mountain passes, rough surfaces, and dangerous obstacles, all enveloped in a dense pall of dust. . . . Are you better in dealing with these ever-recurring problems of driving than the man immediately in front of you, or the man just behind you? If not, he gains and you lose; you drop farther back and are passed from the rear, and as you wrestle mentally and physically with all the difficulties of the trial the excitement of it enters into your soul, and you realise that this is the sport of the gods.” So we see that although Jarrott recognised the enormous fascination, the skill and danger, of driving a racing car, he did not single out cornering ability from all the other factors involved. This was understandable when he was writing of the pre-1904 contests, which took place over long, ruler-straight European highways, with the “right-angled corners, treacherous turns”, but a small part of what he describes as “the glorious uncertainty of everything, capped by the intoxicating exhilaration of speed….” But Jarrott was also regretting that those great town-to-town races were doomed, after the accidents that characterised Paris–Madrid, to be replaced by contests “confined to a circuit which the cars have to travel round and round to complete the distance”. He was very disparaging about these closed-circuit events: “As well compare the charm of long-distance road cycle-racing with a 24-hours’ race on the track. The dreary monotony of grinding out a certain distance over the same road again and again destroys the charm, and instead of calling for the exercise of natural judgement in the negotiation of the road, merely resolves itself into a premium on the most reckless and daring driving rendered possible by the knowledge of the course.” I doubt whether Jarrott would have seen any reason to change his views had he witnessed a British GP at Brands Hatch or the last Tourist Trophy at Silverstone!
The interesting thing in the present argument, however, is that when taking part in these circuit races where continual cornering was called for, he does not appear to have had any conception of how he coped with the changed conditions or why the cars cornered as they did, in spite of winning the “first circuit race ever, the Circuit des Ardennes in 1902”, at 54.3 m.p.h. for the 320 miles on a 70-h.p. Panhard-Levassor. Indeed, Jarrott said of this victorious occasion : “Never was I more bored than during at least three-parts of this race.” He admits that he did not drive over the 53-mile circuit beforehand, although later he says that “A circuit race requires weeks of preparation and training . . . every corner, curve, stone, slope and peculiarity has to be studied and known”. Nevertheless, Jarrott was not only unmoved by the niceties of cornering that for later generations had much in common with performing well in bed or pulling off a sound business deal, but he described nothing of what made the racing cars susceptible to driver-discipline under the stresses of sudden changes of direction. And when you read “My Motoring Reminiscences” by S. F. Edge, written for him in much later times, the same is true, except for the comment, in connection with the 1901 GP 50-h.p. Napier, that “It was a little lower than the touring car of that day, but not much, while nothing was done to increase controllability. . . .” The inaccessible hand-brake, the short wheelbase, and the high driving position were accepted, the book says, because in those times “the designer had only one aim, to make it go faster irrespective of all other considerations”.
It was much the same a decade later, at all events so far as onlookers and reporters were concerned. H. Massac Buist in a long gossip about that dramatic 1914 French Grand Prix at Lyon for The Autocar certainly wrote of cornering, but only of how racing drivers dropped into a lower gear before a turn and of how front-wheel-brakes were worth a minute a lap to the Peugeots; nothing more technical than that. You might think that those journalists who went to Amiens in 1913 to report the Cyclecar Grand Prix would be more technical, because they drove similar vehicles themselves, such as GNs and Morgans. But even in an article entitled “Cornering at Speed” which The Cyclecar published after this race, having observed the “antics” of the competitors on the S-bend under the railway bridge, the reporter was more concerned with the acrobatics of the sidecar and cyclecar passengers than with technicalities. McMinnies in the winning Morgan is described as taking the bend at 25 m.p.h. on the cut-up surface, and Douglas Hawkes as possibly being hampered in the Dew because his mechanic sat behind the back axle, “thus reducing adhesion between the front wheels and the ground”. Although many of the cyclecars were cornering at less than 25 m.p.h. the reporter was only concerned about whether they skidded or not, or whether the crews leaned out or sat normally. The Violet Bogey was the best, followed by the Ronteix, but Frazer-Nash in his GN was very good, too, in spite of no practice. But the only technical conclusions were that cyclecars cornered better than sidecars and that absence of a differential, even on the big GP Sunbeams, “had no detrimental effect so far as skidding was concerned.”
A further decade after this, following the interesting French GP at Tours, won by Segrave in the Fiat-crib Sunbeam after the Fiats had retired, The Autocar had an article on “Cornering in the Grand Prix”. It was not very informative, either, for after observations made at La Membrolle, the writer was again chiefly concerned to describe how little the art of fast cornering was understood in the vintage era is emphasised by these diagrams which accompanied an article by Segrave on the subject in the January 1926 MOTOR SPORT. That on the left shows how to cut a curve, that on the right how to use a skidding technique to get the car’s tail round a more acute corner.the skidding cars and of how De Vizcaya’s tank-like Bugatti crashed through the palisades. Even when dealing with the “niceties of cornering” all he could impart was that Bordino (Fiat) and Guinness (Sunbeam) were quite the best and of almost mathematical precision, but that Divo (Sunbeam) was faster but erratic and liable to skid more. The Bugattis, we were told, were much slower, unsteady, and with rather a nasty trick of swerving, but the Voisins were only occasionally erratic, perhaps because their drivers were more circumspect. The line taken by different drivers was described, Segrave being reported as irregular but every bit as fast as the others when timed. It is interesting that the reporters had cottoned-on to timing at corners by 1923. This timing showed a variation of as much as 4.8 sec. between Bordino’s Fiat and Morel’s Voisin in a short distance and of 5.0 sec. between Divo’s Sunbeam and Lefebrere’s Voisin at another corner. No wonder that the race was won by a margin of more than 19 minutes! For the technique of cornering was still not understood and was for the most part exceedingly slow, and even racing drivers were not sure whether to use the lower gears before and after a corner.
In 1925 MOTOR SPORT sought to do something about this, with a three-page piece on “Cornering at Speed”, by no less an authority than Major H. O. D. Segrave himself. It was pretty puerile stuff, however, simply dealing with whether to change down before a corner or take it in top, how to cut the apex of a curve instead of hugging it (with diagrams!), and how to use engine power to provoke a rear-wheel slide for negotiating a hairpin (but usually Segrave preferred what he termed “geometrical” cornering, i.e., no skidding). There was also a brief discourse on tyres, Segrave at this period liking a triple-rib Pirelli for road racing, a curved tread with fairly shallow, closely placed ribs for track work, and finding “high-pressure balloon tyres inflated to 40-50 lb./sq. in. ideal for fast cornering”.
When Segrave’s book “The Lure of Speed” was published by Hutchinson’s in 1928 it contained a chapter on accidents, with a section devoted to “How to Take Corners”. This merely warned against braking while in the corner, and Segrave confirms my point that very little was known about cornering techniques in the vintage period by remarking that “Time after time one sees even experienced racing men taking corners in a manner that has long been proved dangerous”.
Of course, it was not until softer suspension and lower-geared steering began to be used in racing, just before the Second World War, by Mercedes-Benz and Auto-Union, and in sports-car racing on the 328 BMW, that the significance of design as an aid to fast cornering began to be fully appreciated. Segrave had warned of how, in his day, springing was so hard that a bump would frequently throw both front wheels off the ground long enough for a careless driver to inadvertently turn the steering wheel slightly before they again made contact with terra firma, with interesting and sometimes unfortunate results. . . .
Apart from the racing-car designers of the calibre of Nibel, Wagner, Porsche, Sailer, Uhlenhaut and others, it was the General Motors’ engineer Maurice Olley who studied this new understanding of suspension and tyre influences on cornering and road-holding, even if it is ironical that the Vauxhalls for which he was responsible were not exactly outstanding in these respects. Maurice Platt, MEng., MIAE, MSAE, put these principles into popular language, when he was Technical Engineer of The Motor, and his successor, Laurence Pomeroy, FRSA, MSAE, continued to do this during and after the war when he held the same position on that journal.
Thus things such as roll stiffness, suspension rates, slip angles of tyres and all the rest of it became public knowledge, and the terms oversteer and understeer properly understood for the first time by ordinary mortals. This was expanded by our learned Continental Correspondent, D.S.J., in “The Racing Driver” (Batsford, 1958), where these findings affecting fast cornering were explained in complex diagrams and with erudite mathematical equations and it was explained how the top drivers, like Moss and Fangio, were able to apply them to winning motor races, even if they did so subconsciously, without knowledge of the formulae involved. As when these drivers were able to make the understeering W196 Mercedes-Benz change its handling to final oversteer by the application of power in a fast corner, which Uhlenhaut had not thought it possible for driver-skill to achieve and make good use of.
Today, with lap-times taken to 1/100th of a second, mostly over courses where corner follows corner, car behaviour has become almost a science of its own, with tyre mixes, suspension settings and aerofoil assistance all combining to permit brave and skilled drivers to corner very fast indeed. In this the racing car designer has come a very long road from the simple situation prevailing in the Edwardian and vintage periods of racing. I had a reminder of this not long ago, when I took my 50-year-old Calthorpe light-car for its legality-test. It failed because the footbrake was insufficiently powerful, although the hand-brake met the requirements. So I had to part with much money to have the footbrake shoes re-lined (and I hereby give grateful thanks to Ferodo for promptly supplying the M20 linings and alloy rivets required but which the garage couldn’t obtain). Now this comes about because on modern cars the hand-brake is just a parking brake. But in olden days drivers used the hand-brake for emergencies or for bringing the tail round at a corner when racing. Indeed, the first Austin Sevens had the then-new-fangled front brakes applied by the hand-brake, ordinary slowing down being accomplished with the pedal-applied rear brakes. If Authority had appreciated that when my Calthorpe has to be quickly arrested from its leisurely pace I grab the hand-lever and pull it backwards, as well as stamping on the foot-brake, it would have passed the Test first time and I would have been saved much expense! Nowadays, though, they allow more leniency on the hand-brake than on the pedal-brake.
However, all that is in the distant past. But today there is just as much concern on the part of keen drivers to get closer than their companions to the cornering prowess of Stewart and Fittipaldi as in the past, when their counterparts vied with one another to emulate Nuvolari, Moss and Fangio. You have only to think of those Guild of Motoring Writers’ Silverstone Test-Days with the inevitable spin-offs and inversions, to see what I mean! It is a remarkable facet of the human race in the mechanical age that this yardstick exists, with real remorse felt when you are out cornered by so much as a fraction of a second.—W.B.