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Nigel Mansell, the British motor racing driver, made history this year
by winning the first five Grand Prix of the 1992 Formula One season. He
would have won the sixth at Monaco in May if a wheel nut had not become
loose near the end of the race. And though he spun out of the Canadian Grand
Prix last month, he retains a huge lead in the world championship. Is this
success down to Mansell’s driving skills or the engineering expertise designed
into his car?

Few motor racing experts doubt that Mansell is driving better than ever
for the Williams team. But success breeds confidence, and Mansell’s record
is not spectacularly unusual. This time last year Ayrton Senna, the Brazilian
driver, won the first four races in his McLaren car and went on to take
the 1991 championship.

The difference this season is that Riccardo Patrese, Mansell’s Italian
team-mate at Williams, is also achieving remarkable success in an identical
car. Patrese has come second on four occasions this year and took third
place at Monaco. Even more impressively, the Williams car was leading every
race from start to finish until the wheel nut became loose. Mansell started
in pole position for the first six Grand Prix, and either he or Patrese
was in front for more than 400 laps and nearly 1800 kilometres of high-speed
racing.

So what’s special about the Williams car? ‘The amount of science you
put into Formula One design is what makes the difference,’ says Brian O’Rourke,
a senior engineer at Williams. But key factors deserve the most attention,
adds John Barnard, who has designed cars for McLaren, Ferrari and Benetton.
In an interview published last December in Autosport, a British weekly magazine,
Barnard estimated that the engine accounts for 30 per cent of a car’s success,
the chassis and driver about 25 per cent each, and the fuel 20 per cent.

One of the most noticeable differences between this year’s model, designated
the FW14B, and last year’s, the FW14, is the vehicle’s reliability. The
Williams team won seven Grand Prix last year, but it might have been more
if the car had not broken down during six other races. Those faults have
now been identified and the components refined, is all the detail that
O’Rourke will provide. ‘Reliability comes from testing miles on components,’
he says.

Another difference between the two cars is the suspension system. In
most highway vehicles, the suspension is designed to cushion passengers
from the effects of riding over rough roads and going round sharp bends;
springs absorb the extra loads imposed on the vehicle and dampers prevent
them from oscillating too much. In motor racing, comfort is less important
than ensuring that as great an area of tyre as possible stays in contact
with the track. Unnecessary movement in the chassis is not tolerated, with
the result that the car retains a ‘flat’ profile.

Unlike last year’s model, this season’s car has an active suspension
system. Push rods, which link the wheels to the springs and dampers, pass
through hydraulic cylinders containing electronic sensors. The sensors
measure the loads on the suspension and feed this information to two microprocessors,
one on each side of the car, which also receive data on the car’s acceleration
and the centrifugal forces experienced at bends. The processors regulate
the flow of hydraulic fluid in the cylinders and thus the response of the
suspension system at all times in the race. The result is a ‘rigid’ car
that rides evenly over the track throughout the race, says Patrick Head,
technical director at Williams. This ensures that the airflow under and
over the car consistently provides the maximum down force on the vehicle,
which, above all else, permits faster cornering.

Active suspension systems are not new. Lotus introduced the concept
in 1987 on its 99T car, which went on to win the Grand Prix raced on the
twisty street circuits of Detroit and Monaco. Williams quickly followed
suit and won the Italian Grand Prix at Monza later in the season. However,
substantial changes were made to the Williams car in 1988, including a new
engine, and the active suspension did not work well. Head says the basic
principles of the current system are similar but that the software controlling
the processors is completely different.

The aerodynamics of the 1992 car have also been refined using a wind
tunnel. The team’s engineers have studied the shape of the wings, which
rise above the back of the car and help to force it down on to the track.
They have streamlined the undertray beneath the car, and tinkered with the
geometry of the car’s nose and the shape of the cooling air ducts.

Williams also has the benefit of what is thought to be one of the two
most powerful engines of the current motor racing season, providing the
car with 100 horsepower (75 kilowatts) more than last year’s model. (The
average family saloon produces little more than 100 horsepower when it
is going flat out.) Built by Renault Sport, based in Viry-Chatillon, France,
the 10-cylinder engine in the FW14B generates well in excess of 700 horsepower,
says Denis Chevrier of the Renault team. He will not be more specific. Only
the 12-cylinder Honda engine in the McLaren car is thought to match it for
power.

The extra power has had to be found within the rules on the design of
Formula One engines imposed by motor racing’s governing body, the International
Federation of Motor Sport (FISA). These rules dictate that designers cannot
make engines more powerful by using turbochargers, for instance, to pump
compressed air into the combustion chambers. Air must be simply sucked into
the chambers so that the engines are normally aspirated, like those in most
family cars. The maximum capacity is 3.5 litres and there must be no more
than 12 cylinders, all of circular bore. The amount of fuel used and its
calorific value are also regulated. This year, cars must not use more than
220 litres per race, and the fuel must be no more than 102 octane and have
a specific density no higher than 0.79.

To make the most of the engine and fuel within these constraints, Renault
first looked for the most efficient weight, shape and size of engine. ‘It’s
no good having the most powerful engine if it is very heavy and consequently
has a high petrol consumption,’ says Chevrier. The engine block, cylinder
heads and pistons are made from aluminium alloy, but some other parts are
made from magnesium alloy, which is lighter though not as strong.

Close cooperation with the car’s designers at Williams has also been
crucial. It ensured that the engine’s air inlet ducts were as aerodynamically
efficient as possible, says Chevrier. It also helped to persuade Renault
to stick with a 10-cylinder engine, instead of going for a 12-cylinder one,
which other teams, besides McLaren, are using. There are several advantages,
says Chevrier. The Renault engine is shorter, and requires a smaller radiator
to keep it cool. Both factors give the chassis designers at Williams more
flexibility in producing the most efficient shape.

Chevrier says Renault has considered using a 12-cylinder engine but
has no plans to install one in the race cars. The engine in the Williams
FW14B is the fourth generation of Renault Sport 10-cylinder engines, and
the team believes that further development is still possible. Besides, more
cylinders are not necessarily the best way to go. One of this year’s most
impressive teams is Benetton, which uses an 8-cylinder engine built by Ford.
Other advantages of 10-cylinder engines, says Chevrier, are that they use
less fuel and provide more power for acceleration at low engine speeds than
12-cylinder engines.

When the engines in racing cars are working flat out, their speeds can
be as high as 14 000 revolutions per minute – at half this speed, the engine
in a family car would cut out. But Formula One engineers are not content.
In its pursuit of faster engine speeds to produce more power, Renault and
Elf, the French oil company, have been trying to reduce combustion times
in the cylinders. Chevrier claims that the engine is now running 1000 rpm
faster than last year.

Though neither Renault nor Elf will reveal in detail how they have developed
fuels to burn more quickly, most of their research seems to have been invested
in finding ways to reduce the size of droplets formed when the fuel vaporises
in the cylinders and in experimenting with different cocktails of additives.

Fuels these days must suit not only a particular car, but individual
racing circuits. On slow circuits, such as the one at Monaco that takes
in the twists and turns of Monte Carlo’s streets, power takes precedence
of consumption. But on fast circuits, such as the ‘thirsty’ one at Silverstone,
Northamptonshire with its long straight sections, efficiency becomes the
priority. With cars allowed only 220 litres per race, drivers do not want
to run out of fuel – as Senna did twice last year.

Another difference with this year’s Williams car is that its engine
is coupled to a semiautomatic gearbox. Mansell and Patrese change gear by
flicking a switch on the steering wheel. This enables them to keep their
hands on the wheel at all times and it reduces the period the engine is
disengaged from the wheels. Only three teams, Williams, McLaren and Ferrari,
currently run cars with semiautomatic gearboxes. When Williams introduced
its version last year, problems in selecting a gear saw Mansell lose the
lead on the last lap of the Canadian Grand Prix. So far this year, the gearbox
has proved reliable.

So the Williams FW14B has an aerodynamically improved chassis with a
new suspension, a more powerful engine, advanced fuel technology and a semiautomatic
gearbox. But which of these factors makes it a winner? All of them, says
O’Rourke. ‘All aspects of the car must perform at their best if the car
is to be competitive at the highest level. If any one aspect doesn’t work
the car can’t compete. If one aspect is better than the competition it can
make that car a winner.’ Above all, the Williams car is reliable.

So what is Mansell’s contribution to the success of the Williams team?
‘Mansell is the quickest driver around today,’ claims O’Rourke. ‘Knowing
that he has a good car helps his motivation.’ There is no doubt that Mansell
is motivated. He has now won 26 Grand Prix, just one less than Jackie Stewart’s
record for a British driver. But Mansell has never won a World Championship;
Stewart who won three.

With half the season almost over, Mansell and Williams are already favourites
to win both the drivers’ and constructors’ championships this year. But
the golden rules of Formula One racing are that no more than three-quarters
of a second per lap separates the drivers, and that the more experienced
ones make fewer mistakes. On that basis, a Williams FW14B driven by any
other top driver might look an equally good double bet.

Amanda Weaver is the editor of Reinforced Plastics and Metal Powder
Report published by Elsevier Advanced Technology.