The Trend of Racing Car Design
The period of motor racing which forms the basis for the discussion of design trends, as applicable to Grand Prix cars, in this article will live in history for two reasons. The years concerned were 1959 and 1960, and in that time there has been an almost complete swing to a basic layout where the engine is placed behind the driver, instead of in front of him, as in the previously accepted orthodox racing car. The other reason that these two years will become historic, is that they were the last in a seven-year span of a most successful Formula, even though it was responsible for the death of supercharging in Grand Prix racing, and also for the encouragement of microscopic and rather flimsy racing cars.
Previously in studying the trend of design in Grand Prix circles, I have started with the engine, which I always consider to be the true heart of a racing car, but this time I must discuss first of all the position of the engine. To some extent this change in the positioning of the engine was encouraged by the type of engine being used, and as the compact four-cylinder unit had become almost universal it was not a difficult matter to change its position from in front of the driver, to behind him. Had cars with straight eight-cylinder engines, or even sixes been successful and their designers had wanted to re-design them on Cooper lines, then there would have been some big headaches, but as things turned out B.R.M., Vanwall, Lotus and Ferrari, all of whom changed from front-engined designs to rear-engined designs, were using compact four-cylinder units, or V6 units.
However, before we go into the whys-and-wherefores of the change of heart of designers such as Chapman or Berthon, let us look at the history of the rear-engined racing car. From memory I recall that the Czechoslovakian firm of Tatra built a rear-engined racing car in the early primitive days at the turn of the century, but the first successful, or nearly so, design to have the engine behind the driver, but in front of the rear axle, was the “tear-drop” Benz. This was designed by Dr. Rumpler and raced by the Benz company in 1923, and this must really be considered to be the beginning of rear-engined racing cars as far as Grand Prix events were concerned. Well before this there were various home-made specials with rear-engined layout, but none could be considered as serious designs. Dr. Rumpler’s bright pupil of those early days soon branched out on his own and developed the rear-engined theme in the early nineteen-thirties. This was Dr. Ferdinand Porsche, revered father of the present head of the successful Porsche factory in Stuttgart. Old Dr. Porsche put the P-Wagen Auto-Union into the Grand Prix field in 1934 and continued to develop it until 1937, by which time it was a pretty fearsome and successful Grand Prix car. The Auto-Union was an incredible car for acceleration purposes, and set up many records, but was not the best thing from the point of view of cornering, for the large weight mass at the rear of the car made it a pretty tricky over-steerer. Until 1939 the Auto-Union continued to be successful in Grand Prix racing, but attempts were made all the time to move the centre of gravity forward, and whereas this was difficult with the 1934-37 cars as the engine was a V16, the 1938-39 cars were better placed, having a V12-cylinder engine. Dr. Porsche’s original ideas in designing his P-Wagen were to get maximum traction, by having the largest weight mass near the rear wheels, and to have the rear-end of the car unaffected during a race by a change of fuel load. The World’s standing-start kilometre and mile records set up by Berndt Rosemeyer proved Dr. Porsche’s first point, but his second one was not so convincing. His contention was that if a car was to have an inherently bad characteristic then it should retain that characteristic at all times. In other words, if a racing car was going to start a race with a violent over-steer, then it should finish the race in the same state, and in that way the driver would know what he had to do all the time. The conventional Grand Prix car of those days had its engine at the front and a load of anything up to 5 or 6 cwt. of alcohol fuel in the tail, so that it can easily be appreciated that such a car would over-steer violently in the opening laps of a 300-mile race, and less violently in the closing laps. In addition, races in those days called for refuelling and a tail-light car coming into refuel halfway through a race would set off again as a tail-heavy one, and many a well-known driver has been caught out by this sudden change of condition. The Auto-Union drivers did not have this worry, their fuel tanks being in the centre of the car, and all they had to do was to learn to control the tail-heavy car at the start and then conditions remained more or less static for the rest of the race. Unfortunately, this starting condition was much more difficult to master than Porsche had hoped for, with the result that only a few drivers mastered the technique, but once they did, then the Auto-Union was difficult to beat.
The history books show how well drivers like Stuck, Rosemeyer and Nuvolari conquered the built-in over-steer of the Auto-Union, and race results prove Dr. Porsche’s second point providing suitable drivers could be found or trained.
After the war of 1939-45 the rear-engined Grand Prix car faded from the scene in any serious measure, though a lot of rule-of-thumb knowledge was being gained by British designers in the 500 c.c. movement. It is extremely doubtful whether anyone in 500 c.c. racing put their motorcycle engine behind the driver for any other reason than to simplify the transmission problem. Using a motorcycle engine and gearbox, with chain drive joining them and taking the drive to the rear axle with another chain, as most of them did, practically insisted upon a rear-engine position; and any other advantages later gained were purely incidental. However, these little cars produced a great deal a knowledge on suspensions and steering, but meanwhile the Grand Prix world was persevering with the front-engine layout. One of the most successful in 500 c.c. racing was the Cooper car, and as it grew up it continued with its rear-engine layout until John and Charles Cooper were building nearly full-size Grand Prix cars to this layout. In 1955 they put a Bristol six-cylinder engine into a Cooper chassis, to produce a rear-engincd Grand Prix type car, but it was not so outstandingly successful as the 500 c.c. cars had been, and it needed a Cooper specialist to get the best out of it. They were in trouble, as Dr. Porsche had been with his 16-cylinder cars, of having too much engine behind the driver, but in 1957 they had another go, this time with a light and compact four-cylinder Coventry-Climax engine, and this was much more successful. The development of the Cooper-Climax, from this prototype Formula 2 car to the successful Formula 1 cars of 1959 and 1960, is too recent to reiterate.
In 1954-55 the Connaught firm were working on a rear-engined Grand Prix car using a 250-h.p. Coventry-Climax V8 engine, which unfortunately did not materialise, and this would have probably been as successful as the Cooper subsequently proved to be. By 1955 there was a great deal of knowledge available on racing car chassis design, so that it was quite easy to design-out the basic over-steer caused by having the largest weight mass at the rear of the car. Connaught’s main reason for putting the engine at the back was to get maximum possible adhesion, for they maintained that if there was only going to be 250 b.h.p. available then the total weight of the car would have to be very low if any sort of performance was to be expected. With a low overall weight the weight of the engine was going to be a vital portion and the only way to hope to get the 250 b.h.p. to the ground through the rear wheels, would be to have most of the weight over the driving wheels. Lack of time, money and facilities saw this project still-born, but the 1960 Cooper-Climax four-cylinder almost reached Connaught’s original specification.
When the pattern of Grand Prix racing took a sharp turn in 1958, and the basic requirements of a Grand Prix car changed considerably, as discussed in Trend of Racing Car Design in Motor Sport for February 1959, the small Grand Prix car began to have an advantage over what had become accepted as conventional, and the Cooper-Climax began to become a power in the land. It was hampered at the beginning by being well down on horsepower, compared with its rivals, but in 1959 Coventry-Climax produced a full 2½-litre four-cylinder engine, giving around 235 b.h.p. and this allowed the Cooper to challenge allcomers, except on ultra-fast circuits where sheer maximum speed counted. Maximum speed and maximum b.h.p. are very closely connected, so that at Avus and Reims in 1959 the Ferraris were more than a match for the Coopers, but on any other circuit the rear-engined Coopers were almost unbeatable. They gained advantages on a number of scores, among them good traction, consistent handling, low overall weight and consequent low frontal area, all things which Dr. Porsche had designed into his 1934 Auto-Union P-Wagen.
Naturally, when Coopers began to win important races other designers took an interest in them, and 1959 saw the beginnings of a change of outlook. What had once been considered to be a funny little over-steering rear-engined car had become a race-winner, and so over-steer and rear-engine position soon became fashionable. This was encouraged by a recession in engine design and development as well as a change in engine requirements, for with increased cornering power, thanks to advancement in chassis design, ultimate maximum speed was no longer so vital, but acceleration was. The first to follow the Cooper lead in present-day Grand Prix racing was B.R.M. and in September 1959 they came out with a very Cooper-like vehicle using much of the then current B.R.M., with the four-cylinder engine behind the driver and coupled directly to the gearbox/final drive assembly. It was fortunate that the B.R.M. designer Peter Berthon had been continuing with his 1954 engine design of four cylinders, for had the B.R.M. had a six, eight or V16 engine they could not have contemplated a Cooper-like rear-engined vehicle. Hardly had the sound of the prototype rear-engined B.R.M. died away than Colin Chapman had his designers sat down and designed a rear-engined Lotus in a matter of weeks using a similar four-cylinder Coventry-Climax engine to that used by Cooper. This new Lotus first appeared in the Argentine Grand Prix of 1960, in the early part of the year, and it brought with it many other innovations in chassis design. Chapman had realised for some time that the rear-engine layout for the Climax engined car was essential but designers-pride had prevented him from following the Cooper example; however, once B.R.M. had set the ball rolling he unashamedly joined the rear-engine clan. Naturally other small-time designers of one-off “specials” were already following this trend, but during 1960 the seal was finally set on this change to what was considered unconventional, when Ferrari built a rear-engined car using his V6 Dino engine and then Vanwall put one of their engines into a rear-engine Lotus chassis. There were only two manufacturers left with front-engined cars, Aston Martin and Scarab, the former having an engine much too long to contemplate a rear position and the former having too little time, being already two years behind in design. Although Ferrari did not use the rear-engine layout in Formula 1 Grand Prix racing he did so very successfully in Formula 2 and was obviously gaining knowledge for a new 1961 car. Naturally, while all this was going on Porsche were sitting back and smiling, for they had never built a car with the engine in any other place than behind the driver, while the ghosts of Dr. Rumpler and Dr. Ferdinand Porsche must have been sitting contentedly on a cloud and watching with interest. All the while Cooper were busy winning races, being well satisfied at having stuck to a basic idea born in their minds way back in 1946.
By the end of 1960 a field of cars could be assembled consisting of Cooper, Lotus, B.R.M., Ferrari, Porsche and Vanwall, all with rear-engined cars, while Scarab were working on a new car with such a layout and Aston Martin had withdrawn from racing. In other words the rear-engined racing car was with us to stay. This design trend was slavishly followed in Formula 2 and in the rising Formula Junior, so that in two brief years the definition of a conventional racing car had changed completely.
As regards the engine itself there has been no such radical change, in fact progress has been depressingly poor and the only newcomer on the scene has been the four-cylinder Scarab engine. As this was an almost open crib of half of the 1954 Mercedes-Benz W196 engine, with desmodromic valve gear and near horizontal cylinder position, it can hardly be considered to be progress. The Coventry-Climax firm continued to develop their four-cylinder twin-cam engine, producing a little more horse power, but nothing like as much as some engine designers were getting from the same swept volume six years ago. As the engine was not of such a design that maximum power could be increased considerably, great attention was paid to increasing the torque output and also the torque range, for on most circuits this is what produces results rather than sheer b.h,p. This is a problem that Connaught started developing with their Alta-based four cylinder engine, and Coventry-Climax aided and abetted by Cooper and Lotus have carried the process to its logical and successful conclusion, the Coventry-Climax 2½-litre four-cylinder engine being used in the winning cars of all but one of the major Grand Prix races of 1960. Ferrari continued to develop his V6 Dino engine, always having more b.h.p. than his rivals, but inferior road-holding on the front-engined cars prevented the drivers from using the additional power, while B.R.M. made not very much progress with their four-cylinder twin-cam engine, which dates back to 1954, and Vanwalls rather curtailed racing programme for 1959 and 1960 saw little improvement in their four-cylinder engine, that obviously reached its peak of development at the end of 1958.
In chassis design a notable feature has been the trend towards independent rear-suspension. Independence for the front wheels of a racing car has been agreed upon for many years now, but such independence for the rear wheels has not been popular. A layout on the de Dion principle, where unsprung weight is kept low but the wheels remain connected to one another, and any movement of one influenced the other one, has been popular. Not because it had any great advantage, but it did not have any violent disadvantages, and was easier to design and make than an independent layout, and less liable to vices. One of the simplest forms of i.r.s. has been the swing-axle, but such a layout has always been full of pitfalls, though Mercedes-Benz got over many of them by the introduction of the low-pivot swing-axle design, but even they knew that this was not the ultimate answer. Cooper had adhered to a simple form of i.r.s. that was basically double-wishbones, not from any advanced design theories, but from a number of years of development of a layout used on their first simple racing car. It was a case of i.r.s. worked well on the first Cooper-J.A.P. so such a layout should be retained on all subsequent Coopers, with inevitable development and modification as time went by. The front-engined Lotus-Climax cars used an efficient yet simple i.r.s. arrangement whereby the drive shafts form a suspension member, and this idea passed on to B.R.M. In 1960 Aston Martin built a new rear suspension which was fully-independent, and that day the de Dion rear axle layout, which was at best only a compromise, became dead and buried as far as racing cars were concerned. Ferrari changed to a double-wishbone i.r.s. layout in 1959, along with B.R.M., and in 1960 Vanwall threw away the de Dion tube. Once again a precept of Dr. Rumpler in 1923 had at last reached universal agreement, for the “tear-drop” Benz cars had i.r.s., albeit by swing axles, which we now know to be wrong, but none-the-less the rear wheels moved up and down independently of each other.
From a slavish desire to produce rear independence at all costs, there began in 1960 some interesting developments to try to control the movements of the rear wheels rather than letting them rise and fall, and geometry, like the devil, taking the hindmost. By a careful study of the geometrical movements of wishbones, trailing links, pivot points and so on, designers are now aiming to keep the angle of the rear wheels relative to the ground constant and even to gain a geometrical advantage as the wheel rises. This fine control of rear-wheel movement is only in its infancy, but now that i.r.s. has become essential in the minds of designers there should be some interesting development work on improving current designs. Porsche and Lotus are both loath to let the rear wheels flop idly up and down, and are striving to get the maximum amount of adhesion at all times, no matter whether the suspension is fully compressed or fully stretched. This is being achieved by the use of a combination of trailing links and wishbones.
With the exception of Porsche all other racing-car builders are agreed that disc-brakes are essential and are content to leave their design and construction to the specialist firms such as Dunlop and Girling. The Porsche engineers are still unconvinced about disc-brakes and adhered to well-designed drum-brakes of their own manufacture, and that they may be right can be seen by a number of Formula 2 victories achieved during 1960. I have taken into account Formula 2 cars in this discussion on design trends because at the moment they are very important, as the 1960 Formula 2 car was obviously the prototype for many 1961 Formula 1 cars, as the new F.I.A. Formula for Grand Prix racing came into force on January 1st, 1961. During 1960 it was clear that both Porsche and Ferrari were racing in Formula 2 events with an eye to development work for the new Formula, while Lotus were using Formula Junior for similar purposes.
With the change to rear-engine designs by the majority of racing-car builders, the general shape of racing cars inevitably underwent a change, and much thought went into producing a body shape that did not resemble the Cooper. While copying of the successful Cooper chassis layout was obvious enough, designers did not want to make things worse by making the cars look like Coopers outwardly. B.R.M. used a flat square nose that became rather distinctive, though not very shapely, and Lotus designed their bodywork around the rectangle formed by the water radiator, resulting in the most functional but ugly car designed for some time. Ferrari made little attempt to bother about the bodywork, merely covering his mechanical components with an aluminium body as and where they bulged, resulting in a funny-looking vehicle that at first sight seemed to be going backwards! As is usual, fully-enveloping streamlined bodywork received a little attention and in 1959, at Reims, Cooper-Climax came out with a car that was fully enclosed. It was a rush job, built more by eye than theory, and the result was that it proved rather dangerous and was only used in practice. It went extremely fast, and probably reached 180 m.p.h. downhill, but the aerodynamics were hardly existent and the car practically became airborne. This resulted in the regulations for the German Grand Prix at Avus, the very fast track in Berlin, putting a definite ban on streamlining. This was followed by an increase in interest in Formula Junior, where streamlining had been banned from the start, so that the idea of fully enclosed bodywork began to die a natural death. The new Formula 1 for 1961 also banned any form of wheel covering, so in 1960 there was little point in wasting time and energy on full enclosure, and streamlining for Grand Prix cars, like the de Dion axle and the supercharger, can now be considered buried once and for all.
One aspect of racing-car design that has become almost standardised since the exodus of the supercharger is the use of Weber double-choke carburetter on unblown engines. This Italian instrument, which concentrates on finely-graded fuel/air mixing and control, is used on all Grand Prix cars, except those like Scarab and Aston Martin who used low-pressure injection systems. One reason for the popularity of the Weber racing carburetter is the fact that it is manufactured in sizes suitable for racing engines, but it is surprising that no other make of carburetter has ever looked like usurping its almost universally used position. Solex, Zenith and S.U. have all attempted to conquer the Grand Prix engine, but none succeeded so fully as has Weber. In a similar position, but not for similar reasons, the Dunlop tyre is almost universally used by racing can, but recently there have been signs of the Goodyear company making progress in racing-tyre design.
On the gearbox question there has been little that has been outstanding, though there has been a consistent desire for more ratios, in order to keep the engine working at its peak power output, and Cooper benefitted enormously in 1960 by the introduction of an entirely new five-speed gearbox. Porsche went to the extreme of six-speeds for their Formula 2 car, and I only hope that one day a racing-car designer will get down to things and design a car with either an infinitely variable gear, or a torque converter, suitable for the stresses of racing. As was found in Grand Prix motorcycle design it is easy to get so many gears in the gearbox that the rider is invariably either in the wrong one or continuously changing gear, and it is a simple basic fact that while you are changing gear the vehicle is not being driven forward. At the moment design trends are towards more and more ratios in the gearbox and the new Formula 1 with a limit of 1,500 c.c. on engine capacity, will encourage this still further.
The past two years of motor racing have seen a revolution in racing-car design, with the resultant product being smaller and more compact than ever before, while advances in road-holding and cornering power, helped to a great extent by improved tyre design, has produced high lap speeds with smaller and less powerful cars than only a few years ago. It would seem that the rear engine position has now become almost universal, as has independent suspension of all four wheels. The first season of the new Grand Prix Formula is unlikely to see much change over the 1960 Formula 2 field but 1962 should see great forward strides, with new engines, more power and further advances in cornering ability, from improved rear suspension and improved tyres.
D. S. J.