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Innovations
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.
[edit] Aerodynamics
A Porsche 908 Langheck, German for Long Tail.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 W.M. prototype taped over the engine openings and set a recorded speed of 404 km/h (251 mph) 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 399 km/h (248 mph) under qualifying conditions.
[edit] Engines
An early supercharged Bentley.A wide variety of engines have competed at Le Mans, in attempts to not only 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 569 cc (Simca Cinq) and the largest upwards of 7986 cc (Chrysler Viper GTS-R). Supercharging was an early innovation for increasing output, first being raced in 1929, while turbocharging would not appear until 1974.
The first car to enter without an engine run by pistons would be in 1963, when Rover partnered with British Racing Motors to run a gas turbine with mixed success, repeating again in 1965. The American Howmet Corporation would attempt to run a turbine again in 1968 with even less success. Although the engines offered great power, they were notoriously hot and uneconomical for fuel.
Another non-piston engine that would appear would be a Wankel engine, otherwise known as the rotary engine. Run entirely by Mazda since its introduction in 1970, the compact engine would also suffer from fuel economy problems like the turbine had, yet would see the success that the turbine lacked. After many years of development, Mazda finally succeeded in being the only winner of the race to not have a piston-powered engine, taking the 1991 event with the 787B.
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 M.A.P. 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 2003 with Team Nasamax, leading to the ACO deciding that the 2008 event will see all cars running partial mixtures of bio-ethanol fuel.
[edit] Brakes
With increased speeds around the track, brakes become 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 air brake 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 320 km/h. By the late 1990s, reinforced carbon-carbon brakes would be adapted for better stopping power and reliability.
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