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To be classified in the race results, a car is required
to cross the finish line after 24 hours. This has led to
dramatic scenes where damaged cars wait in the pits or on the
edge of the track close to the finish line for hours, then
restart their engines and crawl across the line to be listed
amongst the finishers. However, this practice of waiting in
the pits was banned in recent years with a requirement that a
team complete a set distance within the last hour to be
classified. Another rule put into place by the ACO was the
requirement that cars complete 70% of the distance covered by
the winner. A car failing to complete this number of laps,
even if it finished the race, was not deemed worthy of
classification due to the poor reliability or speed.
The races traditionally begin with what became known as the Le
Mans Start, in which cars were lined up alongside the pit wall
in the order in which they qualified. The starting drivers
would stand on the opposite side of the front stretch. When
the French flag dropped to signify the start, the drivers
would run across the track to their cars, which they would
have to enter and start without assistance, before driving
away. This became a safety issue in the late 1960s when
drivers would ignore safety harnesses, a recent invention.
This led to drivers running the first few laps either
improperly harnessed due to attempting to due it while driving,
or sometimes not even harnessed at all, leading to several
deaths when cars were involved in accidents due to the bunched
field at the start.
This starting method inspired Porsche to locate the ignition
key switch to the left of the steering wheel. This allowed
the driver to use his left hand to start the engine, and his
right hand to put the transmission into gear. This location
of the ignition key switch is still found today on all Porsche
911 based models.
Feeling this type of start was unsafe, the 1969 event saw Le
Mans rookie Jacky Ickx oppose the method by walking across the
track while his competitors ran. Although nearly hit by a
faster competitor’s car while walking, Ickx took the time to
fasten his safety belts before pulling away. Sadly, the first
lap of that race saw privateer racer John Woolfe killed in an
accident, while Ickx went on to win the race. The traditional
Le Mans practice was altered for 1970. Cars were still lined
up along the pit wall, but the drivers were already inside and
strapped in. At the dropping of the French tricolour, the
drivers would then start their engines and drive away.
However, in 1971, this method would be done away with
altogether as a rolling start (sometimes known as an
Indianapolis start) was introduced, which has been used ever
since.
The circuit on which the 24 Hours of Le Mans is named the
Circuit de la Sarthe after the Sarthe department that Le Mans
is within. It consists of both permanent track and public
roads that are temporarily closed for the race. Since 1923
the track has been extensively modified, mostly for safety
reasons, but is currently 13.65km in length. Although it
initially entered the town of Le Mans, the track was cut short
in order to better protect spectators. This led to the
creation of the Dunlop Curve and Tertre Rouge corners before
rejoining the old circuit on the Mulsanne. Another major
change was on the Mulsanne itself, when the FIA decided that
it would no longer sanction any circuit which had a straight
longer than 2km. This led to the addition of two chicanes,
slowing the high speeds that cars had been capable of reaching
on the old 5km long straight. The public sections of the
track differ from the permanent circuit, especially in
comparison to the Bugatti Circuit, which is inside the Circuit
de la Sarthe. Due to heavy traffic in the area, the public
roads are not as smooth or well kept. They also offer less
grip because of the lack of soft tyre rubber laid down from
racing cars. The roads are closed only within a few hours of
the practice sessions and the race, before being opened again
almost as soon as the race is finished. Workers have to
assemble and dismantle safety barriers every year for the
public sections.
Over its lifetime, Le Mans has seen many types of innovations
in automotive design in order to counteract some of the
difficulties that the circuit and race present. These
innovations have either been dictated by rules or have been
attempts by manufacturers to outwit the competition. Some of
these innovations have made their way into the common
automobile and are used nearly every day.
One of
the keys to Le Mans is top speed, caused by the long straights
that dominate the circuit. This has meant that cars have
attempted to achieve the maximum speeds possible instead of
relying on downforce for the turns. While early competitors’
cars were street cars with their bodywork removed to reduce
weight, innovators like Bugatti developed cars which saw the
beginnings of aerodynamics. Nicknamed Tanks due to their
similarity to a tank, these cars used simple curves to cover
all the mechanical elements of the car and increase top speed.
Once Le Mans returned after World War II, most manufacturers
would adopt closed bodies which were streamlined for better
aerodynamics. This led to a separation from Grand Prix cars,
which rarely had large bodywork.
As the years went on, bodywork became larger while at the same
time lighter. The larger bodywork was able to provide more
downforce for the turns without increasing the drag, allowing
cars to maintain the high top speeds. These extended
bodyworks would usually concentrate on the rear of the car,
usually being termed “long tail”. The bodywork also began to
cover the cockpit for less drag, although open cockpits would
come and go over the years as rules varied. Aerodynamics
reached its peak in 1989 before the Mulsanne Straight was
modified. During the 1988 race, the crew of a WM prototype
taped over the engine openings and set a recorded speed of
404km/h down the Mulsanne in an attempt for some publicity,
although the car was nearly undrivable elsewhere on the
circuit and the engine was soon destroyed from a lack of
cooling. However, for the 1989 event, the Mercedes-Benz C9
reached 399km/h under qualifying conditions.
A wide variety of engines have competed at Le Mans, in
attempts not only to achieve greater speed, but also to have
better fuel economy and spend less time in the pits. Engine
sizes have also varied greatly, with the smallest engines
being a mere 569cc and the largest upwards of 7086cc, while
turbocharging would not appear until 1974. Alternative fuel
sources would also play a part in more normal engine designs,
with the first non-gasoline car appearing in 1949. The
Delettrez Special would be powered by a diesel motor, while a
second diesel would appear in the form of the MAP the
following year. Although diesel would appear at other times
over the race existence, it would not be until 2006 when a
major manufacturer, Audi, would invest in diesels and finally
succeed, with the R10. Ethanol fuel appeared in 1980 in a
modified Porsche 911, taking a class win. The alternative
biological fuel source would return again in 2003 with Team
Nasamax, leading to the ACO deciding that the 2008 event will
see all cars running partial mixtures of bio-ethanol fuel.
With increased speeds round the track, brakes became a key
innovation for teams attempting to safely bring their cars
down to a slow enough speed to make turns such as Mulsanne
Corner. Disc brakes were first seen on a car when the Jaguar
C-Type raced at Le Mans in 1953. The Mercedes-Benz 300 SLR
would introduce the concept of an airbrake in 1955, using a
large opening hood on the rear of the car. In the 1980s, anti-lock
braking systems would become standard on most Group C cars as
a safety measure, ensuring that cars did not lose control
while still moving at approximately 320km/hr. By the late
1990s, reinforced carbon-carbon brakes would be adapted for
better stopping power and reliability. |
