The Trend of Racing Car Deisgn

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UNDER normal circumstances articles under this heading happen every two years, that being considered a reasonable span over which design trends can be viewed with some semblance of meaning. However, with the new Formula One starting last year, racing-car designers have had the opportunity to start afresh, so that I consider one year of development at this stage to justify a study of the trends. This study is restricted to Grand Prix racing, which always has been the pinnacle of motor racing, and I hope always will be especially from a design point of view. It is for Grand Prix racing that the F.I.A. award the Manufacturers’ Championship, which is the principal award sought by racing-car manufacturers. I do not intend to contemplate Inter-Continental Formula, at best an obsolete affair, nor the mooted Formula 366, which is a sort of “Hot Rod” racing, nor Formula Junior, which is development of production component racing, but Formula One, for unsupercharged cars of 1,500 c.c. capacity, with a minimum weight limit of 450 kilogrammes (990 lb,). There are races run by immature racing countries called Grand Prix events, which are for sports cars, but to me Grand Prix races are those of a reasonable time or distance for Formula One cars.

Let us first consider the engine, for in 1961 three entirely new engines appeared, and one more was on the test-bed. When reviewing the situation regarding the 1961 Formula as long ago as December 1958, in MOTOR SPORT, I suggested that progressive engine design should produce a unit that was giving 200 b.h.p. in 1,500-c.c. form. While nobody actually achieved this figure, they were not so far off it, the V8 Coventry-Climax unit gave 174 b.h.p. almost on its first running, the V8 B.R.M. certainly gave 180 b.h.p. the first time out, and Ferrari claimed 185 b.h.p. for his 120-degree V6 engine; the flat-8 Porsche was disappointing on the test-bed, giving only 160 b.h.p. These were known figures last September, so that today, after four months’ development work, we can assume that they have been improved upon. Personally. I doubt whether Ferrari has over 200 b.h.p., even when ” tweaked-up ” on the test-bed, but I am prepared to believe that the V6 is not far short of 200 b.h.p., and that the other engines are not that far behind in maximum power output. I have never subscribed fully to the Coventry-Climax theories of good torque rather than peak power, though I would accept peak power and good torque, if it is possible. The Cooper-Climax victories in 1959 and 1960 were more by reason of a good compromise of power, torque and road-holding, than sheer middle-range torque as some people suggest. Had the Cooper used a Ferrari engine, with its superior maximum power, it would still have won. To my mind there has always been a horsepower race, ever since motor racing began, and, given other things equal, the most powerful engine will invariably come out on top.

The three new engines in 1961 make interesting comparison, the Ferrari being a V6 and the Coventry-Climax and B.R.M. V8 cylindered. Ferrari used an included angle of 120 degrees between the cylinder blocks, while the other two used 90 degrees; I do not discuss the Porsche-8 here as it has yet to appear on the circuits, there being three stages of engine to my mind, stage 1 being the drawing-board, stage 2 the test-bed and stage 3 the chassis, with a subdivision in stage 3 of appearing in open competition with unbiased timekeepers. Stages 1 and 2 are only of academic interest, it is stage 3 that really counts. Ferrari dimensions were 73 x 58.8 mm., Coventry-Climax 63 x 6o mm., and B.R.M. 68.1 x 5o.8 mm., and naturally all use twin overhead camshaft layouts on each bank of cylinders, though the drive of the camshafts varies, Ferrari using gears, Coventry-Climax gears and chain, and B.R.M. gears, while they all used conventional port layout, with the gases going in one side of the head and out of the other, with one valve in each hole, and hemispherical combustion chambers. Ignition systems show some new thinking, for Ferrari uses coil ignition, with two distributors at the front of the engine, and two plugs per cylinder, while the two English engines use only one plug per cylinder and fire them by a new form of ignition designed by the Joseph Lucas experimental department. This takes the form of transistor-energised h.t. current, distributed by means of magnetic segments on the flywheel, timed with a simple distributor-head rotor spreading the sparks round an eight-point cap, thus doing away with make-and-break contacts, and mechanical bits that have speed limitations. Between Italy and England the magneto for Grand Prix racing at last seems to be heading for the burial ground.

Feeding gases into these engines is one of the major problems, especially with the Coventry-Climax and the B.R.M. Having an engine is one thing, but having a mechanism to make it work is another, and by that I mean a carburetter or fuel-injection system. Of all racing engine builders, with the possible exception of Daimler-Benz, Ferrari is the best placed in this respect. The fact that Enzo Ferrari and Edoardo Weber were chums in the early ‘twenties still counts for something, even though Weber himself is long since dead. The close co-operation between Ferrari and Weber on the question of carburetters is something often overlooked by his rivals. If there was any other carburetter suitable for Grand Prix racing this would not be very important, but the simple fact is that the Weber firm are the only ones to market a racing carburetter that successfully wins races. The only time they have been usurped from the winning cars is when Mercedes-Benz and Vanwall used Bosch fuel-injection. A close look at the carburetters on the no-degree Ferrari engine will show that these 40 IF3C instruments were not taken off the production shelf, nor were they designed in the general run of carburetters. While designing the cylinder heads and inlet ports Ferrari also designed a carburetter to suit, naturally with the close co-operation of the Weber experimental department, and the prototypes of these triple-choke downdraught instruments were actually cast at Marenello, the patterns being made in Ferrari’s own pattern shop. With the other two engine manufacturers at present in Grand Prix racing, Coventry-Climax and B.R.M., they both had to design their engines in the hope that Weber would have a suitable carburetter design to fit their port diameters and centrelines. As it turned out Weber had nothing suitable for either of the V8s, Coventry-Climax making do with a batch of obsolete 38 IDF Webers that had been designed for a Ferrari engine some time ago, and B.R.M. being unable to find anything suitable. The Climax had a horrible-looking collection of angled and divergent pipes brazed-up to take the IDF Webers, and B.R.M. turned to Lucas fuel-injection. The Bourne people have done some test-bed experiments with 35 IDM Webers, a carburetter designed for a Maserati engine. After the season Coventry-Climax obtained some 38 DCNL Webers, made for Lancia, as the supply of the earlier IDF had dried up completely. Of course, the Weber firm would design and make special carburetters for both these engines, but naturally at a price, which neither firm seem prepared to pay. In basic engine design I was always brought up to believe that the progress of the gas from the bell-initial entry to the valve seat was all important, but maybe these basic ideas no longer hold good, though obviously Ferrari believes in them.

Regarding the fuel-injection on the B.R.M., this is of the low-pressure system. i.e., around 100lb./sq. in., as against 450lb./ sq. in. on the Bosch high-pressure. So far this has: been tried on Alta in 1952, Jaguar, Aston Martin and Maserati engines since, but has never been proved to show any advantage over racing Weber carburetters, and everyone has dropped it after a time. If it can be made to equal the Weber carburetter on all counts then its use is more than justified, and the B.R.M. layout, which is very neat and tidy, may well remain. They mount the injection pump in the vee of the engine, not the best place from the heat point of view, but convenient for driving it by an internal-toothed rubber belt from the right-hand inlet camshaft. insulation of the Bosch pump on the W196 Daimler-Benz engine, and the precautions Vanwall took to keep their Bosch pumps cool, should have convinced any designer of the necessity for placing an injection pump in a cool place. If only S.U., Solex or Zenith were able to cope with racing-engine carburation and work in close co-operation with Coventry-Climax and B.R.M., then a lot of problems could be overcome at both factories. Exhaust systems on these new engines are interesting, for Ferrari and B.R.M. use very simple take-off pipes from each cylinder, merging into tailpipes for each bank, the B.R.M. no longer being so fussy about equal-length tubing, thus doing away with the gaggle of pipes around the exhaust ports of the old 4-cylinder B.R.M.. The Coventry-Climax exhaust system on the V8 as fitted to Cooper and Lotus last year was truly remarkable; the old adage ” if a thing looks right it usually is right ” is more often than not absolutely true. The exhaust layout on the Climax looked anything but right, though it was claimed (a) that it was worth 10 b.h.p. and (b) that it was an important factor in torque. It demanded that pipes from opposite sides should be mated together before passing into the tail-pipes, so that the conglomeration behind the engine where the eight pipes merged into the two tailpipes had to be seen to be believed. If (a) was true then there must have been something basically wrong with the Climax design, for it meant they were scratching for the last available horsepower, and still not up to their rivals, and if (b) held good it was a matter of opinion as we have already discussed.

Now to chassis design, which is very much separated from engine design in the case of Cooper and Lotus, and this year Lola, but Ferrari, Porsche and B.R.M. can design their engine and chassis on the same piece of paper. All these manufacturers are agreed on one principle, and that is that the engine should be behind the driver but in front of the rear axle centre-line, with the gearbox behind the centre-line, thereby being satisfied with an oversteer characteristic built-in by reason of the weight distribution, no-one showing any interest in low-polar moment design, as practised by Connaught and Lancia in the previous Formula. The only dissentient to the 1961 accepted layout is Ferguson, who not only use front-engine mounting, but also have a low-polar moment, but both these factors are closely tied up with the fact that the Ferguson uses 4-wheel-drive, and will be discussed later, Of the orthodox Grand Prix cars of 1961, Ferrari and B.R.M. show every evidence of the chassis and engine design haying progressed hand-in-hand; in passing, it is interesting that what we now accept as orthodox was tried by Benz in 1923 and considered a freak, by Auto-Union in 1934, when it was considered unorthodox and revolutionary, and by Porsche and Cooper in the 1958 Formula Two, when it was considered a design compromise rather than a basic layout. Now it is accepted as a basic layout. To use the Climax V8 the Cooper chassis had to be chopped about and then changed again when the engine arrived because the sump was 2 in. deeper than on the original drawings, and the exhaust system demanded the engine being mounted 2 in. further forward; and the same problems confronted Lotus, though only a 1960 chassis was modified to take a V8. The 1961 Lotus Chassis was designed with the Coventry-Climax V8 drawings alongside their drawing-board, but the changes made in the Climax between drawing and production meant that it would not have fitted in the sleek Lotus chassis. Fortunately they did not get an opportunity to try, only Cooper and Walker receiving V8 engines. Everyone is agreed on full independence for all four wheels, and in general a form of double-wishbones and coil-springs is universal on the front, even Porsche at last discarding the trailing links and torsion bars that date back to Dr. Ferdinand Porsche and 1934. Lotus produced a system of front suspension that was started in 1948 by Massimino at Maserati, whereby the top wishbone was a solid arm in the form of a rocker, pivoting about the chassis, and the inner end of the rocker presses on a coil-spring. This gives a low frontal area, for the coil-spring/damper unit is inside the bodywork. The lower wishbone is more orthodox. Cooper. Ferrari and B.R.M. all used forms of double-wishbones with interspersed coil-springs, while Lola use much wider based wishbones and radius arms as well. Rear suspension follows two schools of thought that can be divided into Cooper or Lotus, the former being double-wishbones with interspersed coil-springs, with variations on the theme by Ferrari,. B.R.M. and Porsche, each having their own particular choice of geometry and wheel movement, while the latter is a form of independence that uses transverse arms in conjunction with twin radius rods to take fore-and-aft stresses, rather than letting the wishbones do this, as on Cooper layouts. Everyone is agreed on coil-springs. The multi-tube space-frame is now universal and Lotus make use of the frame tubes to carry oil and water to and from the front mounted radiator. With the exception of Porsche the disc brake is universal and 1961 saw the Stuttgart firm experimenting with their own disc brakes, whereas everyone else is happy to leave things to Dunlop or Girling. Tyres are universally Dunlop so have no bearing on design, being equal for everyone, while wheels still have variants, Ferrari remaining faithful to wire spoke wheels, everyone else using some form of alloy disc or cast wheel, only B.R.M., Ferrari and Ferguson deeming it necessary to have knock-off fixings, the others using bolt fixings. The wisdom of which choice being best was tested severely at rainy meetings in 1961 when Dunlops produced ” wet ” and ” dry ” tyres. It is now accepted that the ” wet ” tyre is also suitable for ” dry ” conditions, so this bogey is no longer with designers.

To revert to mechanical components the gearbox shows a lot of variation, though the trend is towards more and more ratios, Cooper, Porsche and Ferrari all using 6-speeds at times last year. The necessity is forced by the high r,p.m. of the 1,500-c.c. engines, and the narrow re-bands, but this can well turn into a vicious spiral, as Moto-Guzzi found out some years ago. They built 4-cylinder and 8-cylinder engines of 500 c.c. requiring more and more speeds in the gearbox, until the rider was changing gear almost continuously. They then reverted to a thumping great single-cylinder 500 c.c. and a 4-speed gearbox and found the bicycles lapped just as fast ! Ferrari and Porsche design and make their own gearboxes, Cooper design theirs, which is made by Jack Knight, Lotus design theirs in conjunction with ZF of Germany, who make them, while Lola use a Colotti gearbox, as do various other people. For the bodywork Lotus use fibreglass, while Cooper have experimented with this, and the rest use good old-fashioned aluminium, or a variant of that metal.

So far I have excluded the Ferguson from these design trends, for the simple reason that on almost all counts Claude Hill, the Ferguson designer, is at variance with the orthodox of 1961. This is not for reasons of wanting to be different, or from reason of knowing better, but simply that the whole principle of the Ferguson encourages a different outlook. Take engine position; with 4-wheel-drive there is no need to concentrate the weight mass over the driving wheels, which is the main reason for all conventional 2-wheel-drive Grand Prix ears being rear engined. With the driving wheels at both ends the weight can be spread about the chassis, though it is desirable to keep it all between the axles to encourage neutral-steer at all times, as 4-wheel-drive responds to this steering characteristic best of all. In consequence the most compact layout was front engine, angled to the left, with the driver fitted into the wedge on the right. The driver’s seat being his widest part and his feet the narrowest, when in a driving position, meant that he fitted neatly into the wedge formed by putting the engine at an angle in front of him. With the drive being taken to both ends of the car the obvious place for the gearbox was in the middle, thus solving another problem, and once again adding to the low-polar moment. With all four wheels having drive shafts going to them and all brakes being inboard it meant that all wheels had driving and braking forces acting through the centre-lines in a horizontal plane. This enabled a single wishbone at hub-centre level to take all the stresses, while it also simplified the geometry as the drive shaft and wishbone could be made to pivot on the same centres. In consequence the upper wishbone to the hub carrier pillar could be very simple and light, as all it had to do was to stop the wheel toppling over. The inboard brake mountings were deemed necessary for reasons of unsprung weight as well as the advantages just mentioned, and whereas people have tried and failed with such mounting, except for Daimler-Benz in the past and Ferrari this year on the rear, the Ferguson avoids heating troubles by providing the differential units with dry sump oiling.

As far as 4-wheel-drive is concerned it is pretty obvious that Ferguson have solved most of the problems, and its superiority over conventional British Grand Prix cars was demonstrated fairly conclusively at Oulton Park last year. But it did have Moss as driver and earlier in the year at Nurburgring he showed a similar superiority over everyone else with a 1960 Lotus, so maybe 4-wheel-drive is not yet a ” must.” If it is, then the Ferguson system of a central differential with automatic clutch unit would seem to be the answer.

Already after only one season of 1 1/2-litre Formula One racing we have an interesting complexity of designs in the Grand Prix field, with high hopes for success for everyone, each designer as convinced as the next that his layout is right. It would be nice if they could all win a single Grand Prix for then we would know they were all right in their designs; if we could have a dead-heat with Ferrari, Porsche, Cooper, Lotus, Lola, B.R.M. and Ferguson all abreast over the finishing line, we would not only have confusion on the track but confusion on the drawing-boards, for it would mean they were all right, or all wrong.—D. S. J.