Written by — Ranjan Manohar
It had finally happened. After toiling for years in the car and motorsport business, having aimed higher than anyone else (a bit too literally) Mercedes had created a version of the flying car from ‘Back to the Future’ for the 1999 Le Mans season.
Unfortunately for them though, that was not quite what they’d planned.
And car number 5 with Peter Dumbreck at the wheel taking to the skies during the 24 hours of Le Mans, that was definitely not what they’d planned. Mercedes was forced to retire from all their motorsport programs for the year of the incident, and have since never been seen in Le Mans.
The 24 hours of Le Mans as we know today belongs to a series known as the ‘World Endurance Championship’ managed by a governing body called the FIA (Federation Internationale de l’Automobile). But, back in 1999, the Le Mans 24 hours, held at Circuit de la Sarthe in France was an independent race that enjoyed a lot of fanfare and technical development. Starting off as a way for automobile manufacturers to prove the reliability of their cars in the early 1920s, Le Mans eventually became a race for every car manufacturer to conquer. For example, in the 1950s, Porsche practically gambled the existence of their company on winning Le Mans!
The importance of Le Mans is not only for car manufacturers, though. As mere mortals, we must be thankful for the technology that came to us, thanks to Le Mans. The front-engine front-wheel-drive layout in modern cars came to be on the Circuit de la Sarthe in 1927. This gave us more cabin space and better grip in some conditions. Some other much simpler comforts that we take for granted today like the seat belt, disc brakes and even windshield wipers owe their development to Le Mans.
When it had just begun, the early track used for the race was a piece of public road sealed off for the race duration. As the race gained more momentum, portions had to be dedicated to accommodate the fans that came every year and ensure their safety as well. Today the track spans about 13.629 km with a legendary piece of straight road called the “Mulsanne Straight”, which is broken by a chicane.
Come the 1999 season, Le Mans introduced a new series of cars called the LMGTP cars (or Le Mans GT Prototype). These cars were built specifically for the 24 Hours of Le Mans and were blistering fast, like, 350kmph fast. To nobody’s surprise, Mercedes targeted the highest possible level of Le Mans and tried to go higher still. Their car was sleek and low, and used every trick imaginable to be the best of the best.
But in the chase of outright pace, Mercedes sacrificed aerodynamic stability. To the shock of the team and the drivers alike, the cars took off the track and somersaulted thrice during the race- twice with Mark Webber at the wheel and once with Peter Dumbreck.
The Mercedes cars were what one would call ‘pitch sensitive’. This meant that the dynamics of the car depended heavily on its rocking motion (known as pitching). If the pitch angle remained negative (rear higher than the front), the car channeled air upwards. The equal and opposite force caused pushed the car onto the track. This is what came to be termed as “aerodynamic down-force”, which keeps the car stable and prevents it from taking off as it gets faster. It also pushes the tires harder into the ground as the car gets faster so that turning at high speeds is possible.
A key point to note here is that aerodynamic down-force depends a lot on how ‘clean’ the air is for the car to channel. If nothing is punching through the air in front (like say, another car), it works as predicted and simulated by the team. However, if the air is ‘dirty’, a certain level of unpredictability takes over, and the car behind the one causing the ‘dirty’ air begins to lose down-force. This is quite disastrous, as the speeds we are talking about here are well above what you and I can touch even on the finest stretch of expressway.
But how are pitch angle and the aerodynamic down-force connected? There are two situations where the pitch angle gets bigger and reaches positive values - when the car accelerates and when the car goes up and down a bump. Since a part of the racetrack was still a public road, the surface wasn’t what one would call parfait. Predictably, Mark Webber went over a bump in the dirty air of the car in front during qualifying. Due to this, the car was disturbed beyond the stability offered by the generated downforce, resulting in the car taking off.
Mercedes didn’t give up though. On the recommendation of genius aerodynamicist Adrian Newey, they fitted some dive planes at the front, stiffened the rear suspension to reduce the rocking motion, and went ahead with the race. But lady luck didn’t seem to care as Mark Webber’s Mercedes took off again during the warm-up lap and 5 hours into the race, so did Peter Dumbreck’s.
Mercedes was fiercely fortunate, though. The cars had not caused any casualties unlike back in 1955 when it careered towards the crowd; a flaming hunk of metal killing 83 spectators and the driver. Did Mercedes get too greedy? Probably. But if people behind the pinnacle of motorsport do not push the boundaries, we as the public would not get to enjoy some spectacular stories behind the innovations. More importantly, more the innovation, the more the new technology trickling down into commercial vehicles and reaching our shores. There is always a fair bit of courage and risk involved in the world of motor-sport. That extra 100 milliseconds gained on the competition can mean winning or losing a race, even when the race spans for 24 grueling hours. What Mercedes did was what any manufacturer would’ve done in their position. They put the best design they could on the table and went with it. And this is something that must always be respected — whether it is a car that is tasting victory or whether it is one at the very back of the pack.
