Sunday, 19 June 2011

Le Mans Crash Analysis

Crash 1 - Allan McNish
Towards the end of the first hour of this year's 24 Hours of Le Mans, Scotsman Allan McNish in the #3 Audi Sport North America Audi R18 TDI was overtaking a fellow Audi R18 when he suddenly realised why the #1 car was going slowly - there was a Ferrari GT car just ahead of him. The result was spectacular, and a demonstration of modern racing car safety. But did it need to be so severe?

You only really need to see the first 3 1/2 minutes of this vid

The general consensus is that it was a lack of visibility. As that turn goes left downhill and then right, the #59 Luxury Racing Ferrari 458GT was hidden from McNish's view by the #1 Audi R18, meaning he didn't see him until it was too late. Of course, Le Mans Prototype (LMP) cars are much faster than the GT cars, so they can in theory just drive straight past. Alas, the rules state that they must find a way past the GTs, whose instruction is to stay on the racing line when an LMP approaches. This is so that the LMPs know what the slower cars will do and thus where they can pass. So McNish didn't spot the Ferrari in time, and the Ferrari was just following the rules, but later in the race a EuroSport commentator reckoned that rear visibility was the problem, and the GT car didn't know he was coming either and thus didn't get out of the way of the faster car. Is that a fair argument?

Well, no. Not really. It is true that rearward visibility is an issue in motorsport - F1 recently banned wide-set mirrors because they were so far away from the drivers' line of sight (in order to act as aerodynamic devices), that they ended up turning in on someone in a 1st-corner scrap or some such like and causing/not avoiding an accident - and LMPs don't have rear windows. The GT cars' view out the rear window is usually full of spoiler or engine as well, but at the end of the day, GT cars are supposed to stay on the racing line in this situation, so that everyone's on the same page. Weather McNish's fellow Audi had been there or not, and weather the #59 Ferrari had seen McNish or not, he was always going to take that line through the corner. As it stands, there wasn't really anything either driver could do about it, and it is in fact simply a racing incident, however severe it was.

Another key factor in this crash is the barrier. Just on the right of this picture (visible at 1:30 in the video), part of it is sticking out, presumably to act as a point of entry/exit for service vehicles and retired cars being removed from the circuit. This is actually, I believe, the reason McNish ended up rolling over. If you look at 2:20 or so in the above video, during a slo-mo replay, he actually hits the extruded part first, which get him a little airborne. If the car hadn't hit that, or if the wall was all even, the side of the car would've just slammed against the tyres and bounced off (like the Ferrari did, only harder). Yes, this would still send a serious force through the driver, and the car would still have lost a lot of bodywork and maybe a wheel, but the mixture of the energy absorbing tyre wall, the crash structure in the car and the Head And Neck Safety (HANS) device the drivers wear around their neck nowadays, he would've just wobbled around in the car, dusted himself off and got out feeling disappointed that he'd binned it 1 hour into a 24 hour race. Instead, the top half of the car that didn't touch the tyres tried to keep going (Newton's 1st Law), and as a result the car flipped over and disintegrated as a lot more of the body than usual hit the wall hard and broke off. In fact, photographers had to run and cower in fear of being bludgeoned by a wheel or impaled by a shard of carbon fibre.

You can also see in the picture - where the beige line of gravel sweeps from below the red arrow to the damaged metal wall - and looking again at 2:22 onwards in the vid, that he approaches at quite a shallow angle, going just as much backwards as sideways. As a result, again because of Newton's First Law, as the back suddenly stopped the front end came round. All this adds up to what you see. Unfortunately, I can't back this up with any harder evidence than what you can see in the video, but it seems logical enough. It would be nice to see McNish's on-board camera footage to get a better idea. Speaking of Mr. McNish, he was taken to hospital for check-ups and was deemed to be OK, with no serious injuries. The only effect it may have is causing him to be a little gingerly when overtaking someone at that corner next year...

Crash 2 - Mike Rockenfeller
At around 22:40 local time, the leading Audi, driven by Mike Rockenfeller, attempted to pass a different Ferrari 458 GT, this time the #71 car of Robert Kaufman, at the second right-hand kink heading towards the Indianapolis corner - one of the fastest parts of the circuit - and ran out of road... before making contact and running out of grass at around 190mph.

German commentary. Wreckage at first, then replays at 4:44, full-speed on-board at 7:48

Again, I hesitated to blame the Ferrari driver in this incident. He appears to stay on-line as instructed, and he is racing his own race. Herr Rockenfeller is also racing his own race, and wanted to get past the GT car as fast as possible, so as not to lose time against the rival Peugeot cars. Two tried to go into one, which is of course impossible. At ~200mph, it really doesn't feel like there is much room in these corners (even lapping it in a decent video game will tell you that), and if the Ferrari had gone off-line and stayed on the outside, he could easily have run wide and hit the very close barrier on the left at well over 180mph. Similarly, if Rockenfeller (or 'Rocky' for short) had tried steaming round the outside, he would've run wide at an even higher speed and still had a serious accident, although not as serious as it would've been almost side-on, rather than head-on with locked-up brakes.

As it turned out, Rocky was so determined to get down the inside he even took to the grass a little when he saw the #71 Ferrari inevitably turn in, before clipping the left-rear corner of the #1 R18 TDI and sending him sliding at 90° into a metal barrier at around 186mph (300km/h), at which point Rocky's car also disintegrated. According to some - it's a little hard to say for sure watching the video - the car actually split in half and the cockpit went over the opposite wall with the driver still inside it. Unfortunately for us, on-board cameras don't have a carbon fibre safety cell, so the footage cuts out on impact. Kaufman's on-board would only have shown us a bump and then an Audi going from right to left. The CCTV camera used to show us the carnage surely caught the whole crash, so why TV broadcasters weren't allowed to use it for replay footage, I really don't know...

Full-speed exterior replay at 0:52

It looked like another serious racing incident, one with no blame to place. Mike Rockenfeller, after going through an even worse crash than Allan McNish, landed the right way up this time and managed to get himself out of the car before any medical staff had arrived. They couldn't find him at the scene of the incident because he had started walking towards the nearest medical post! Truly a man of steel, and someone who has his priorities right. He was also feeling a little shaken up, as you can imagine, but the only physical injury was a small flesh wound to his right arm. Somehow. Maybe a bit of car came off and hit it. The Ferrari driver, like the other one involved earlier, continued on to finish somewhere in the middle of his class, however, he was later disqualified for causing this incident. Really? Did the organisers just want to be seen to be doing something?

Something I didn't know until I started writing this article is that there are warning lights all along the track. The reason for this is that, even with the differentiation in colour between each class's headlights (white for Prototypes, yellow for GTs), it's actually very hard to tell who's behind you and how far away they are, because the headlights obviously need to be bright enough to light a pitch black Mulsanne straight all through the night - coincidentally, the Audis' white LED headlights are particularly bright compared to even other prototypes - and this makes them blindingly bright in your mirror. So, if a GT car needs to be wary, a warning light flashes on the side fence, telling them to watch out and maybe back off a little or leave a gap for the LMPs in the name of safety. The driver of the #71 Ferrari 458 went through ten of these warning lights and still failed to yield, so despite initial appearances, it actually was an avoidable accident and it was caused by Robert Kaufman not giving a much faster Mike Rockenfeller any leeway for getting past. Unless for whatever reason he just didn't happen to see the warning lights (Rocky's on-board shows no other cars ahead of them, so he can't have assumed the approaching LMP had already passed), he surely must have realised it was futile to try and fend off a car with at least 60 more horsepower and weighing around 200kg less? Maybe it was fatigue, I don't know...

Still, Audi got their own back. After suffering two horrendous crashes that would've killed the drivers even as recently as the Group C era of the late '80s/early '90s, the lone #2 R18 TDI pounded on against the three-strong factory Peugeots (who tried some dastardly defending tactics to hold them back) to win the 2011 24-Heures du Mans. Audi have won this race 9 times in recent years, making them more successful here than Ferrari, but this win will arguably be their most satisfying. While the three of them crossing the line in formation last year was a moment of huge pride, I'm sure, winning under these circumstances after an emotional rollercoaster as turbulent as that is something else.

At 2:36 you can see Lotterer go through the corner Rockenfeller crashed at. Flat out.

Feel free to skip about 5 minutes into the above video if you don't want to hear the commentators rambling on.

A Quick Look - GT Pro Crash
There's more than one happening here, of course. While the prototypes battle for outright victory (unless they're in LMP2, which is sort of like a stepping-stone class for low-budget teams or car makers testing engines for next year), the LM GTE cars - divided into Pro and Am classes to suit different experience levels and budgets - are battling the Battle Of The Supercars. There are also Lotus Evoras racing in this class. A story similar to Audi's started to unfold with around 7 1/2 hours to go, when the #74 Corvette crashed hard out of the class lead going through a flat-out high speed corner, brutally taking a Porsche 911 GT3 with it.

Replay at 3:18. Marshals not waiting for Safety Car before then

This is pretty straightforward, as Le Mans crashes go. Jan Magnussen in the leading Corvette tried it on up the inside and lost the back end, swerving him into the #68 Porsche driven by Horst Felbermayr. In an attempt to straighten up, he ends up making contact with Felbermayr again and squashing him up against a concrete wall, before spinning round 180° and smashing hard into the opposite concrete wall. Determined to soldier on, he still tried to bring it into the Pit Lane mere metres away, but in the end had to beach it on the entry road.

The description in one video (with German commentary) states that Felbermayr in the blue Porsche suffered a "broken pelvis, a lung contusion and lots of bruises". Yikes! Aside from, of course, the two heavy impacts from the Corvette followed by a HUGE impact with an immovable concrete wall, the extent of his injuries could partly be down to the way GT cars are built compared to the LMPs, where both drivers effectively dusted themselves off after much worse-looking incidents. Because they are based on road cars, they don't have a carbon fibre tub and safety cell like the purpose-built Prototypes. Instead they have whatever the road car has in terms of structural driver protection, minus the airbag to save weight (and because drivers are held in by 5-point harnesses and thus don't move around as much in their seat), but with the addition of a large "Rollcage" made of strong metal tubes. They're not dangerous, by any means. Not any more dangerous than the inherent risks in motorsport make them, but they aren't quite as rigid as LMPs.

Bonus Video - Thank You For Flying Air Ferrari
To reward you for reading this much, here's a clip from the support race featuring Ferrari 458 Italias, in which one car gets a left-rear puncture heading down towards Indianapolis (just after where Rockenfeller crashed) and spears off into the wall. Clearly Ferrari never put the 458 in the wind tunnel sideways to see what would happen!


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