Meet the hydrogen-powered Aston racer

Each May, manufacturers and men in sheds from all over Europe brave a day-long death by a thousand cuts to compete for the crown of ‘King of the Ring'. In the stands and Mad Max style shelters dotted around the infield, a quarter of a million German race fans escape cities of squared-off concrete to worship their Nürburgring heroes. This is a pilgrimage. And it's possibly the greatest motorsport event... in the world.

This year TopGear.com was there to follow a true world-first: Aston Martin's Rapide S race car, a joint project with hydrogen fuel cell evangelists, Alset Global. Aston's centenary celebrations forced a rather fast birth for this car. Alset planned an eighteen-month gestation, but the pregnancy lasted just half that...

"Aston Martin is approached by many crazy people every year," says David King. "We initially felt Alset might be another bunch of crazies, but were quickly convinced by their passion, and the science behind it. Alset brought remarkable technical expertise to this project. We've had no arguments, and no disappointments: it's a model relationship."

CEO and former World Taekondo Champion, Jose Ignacio Galindo (known as Nacho), has built an impressive team of scientists and strategists. And ahead of the race, his passion is highly contagious...

The Nurburgring's all about passion. We've blasted from Frankfurt in gloriously unexpected sunshine, and as we arrive at the track, spirits are high (and - in liquid form - ubiquitous around the campsites). The world's loudest beach buggy zooms past on the perimeter road, trailed by old army trucks, tuned quad bikes, a Unimog with a garden shed for its owner to sleep in, and every wacky racer imaginable. Through the trees,fine-sized schweins are meeting their demise on spits.

‘Ring Time passes faster than a Vantage through Fuchsröhre (the Foxhole). In what seems like an instant, two days have passed, two qualifying sessions have been & gone and we're into the third and final contest: the Top Forty Shootout. The forty fastest runners leave the start in measured intervals, to storm the Nordschleife in free air for a pair of fast laps.

Top Forty always brings a few surprises. This year, the 007 Aston of Pedro Lamy throws down a solid opening challenge, but is instantly eclipsed by a slippy R8 Audi. Lamy goes even harder, firing the car into its second lap and bidding for the front.

The helicopter cameraman only has eyes for the Aston as it approaches ultimate velocity, streaming through the trees in golden evening light. Lamy looks a dead cert for pole, but the Audi has also done well and top guns the shootout. The start will see Audi before Aston, but there's an awfully long race tomorrow...

Three hours before race start we enter the Aston garage. A month's rain is predicted to fall on the Eifel tonight and tomorrow. The race is often wet, but has only been stopped for rain five times, since the first 24-Hour in 1970.

The Aston mechanics shrug off the prediction. This crew's been racing at the ‘Ring since 2006 and has seen enough water to sink the vast grandstands. Aston road cars are developed at the Nürburgring: a key part of sign-off is 10,000 kilometres of ‘Ring durability. The group has a technical centre over the road, to retreat to when testing shows problems.

Two hours before the start, the cars are rolled to the grid, where Germania is in full swing. Liberal use of latex and cheap makeup is the order of the day for one soft-porn-sponsored team (there had to be at least one), while fans wearing model Nürburgrings on their heads shout "Save the Ring!". No one can move on this sardine-tight grid; not an ideal protest start.

"Save It, Don't Sell It" is everywhere. Posters are taped to all trucks in the paddock, banners line the track, and the motto is painted on the asphalt. After years of political mishaps and failed attempts to bolt a theme park onto the side of the track, the Nürburgring is up for sale. While this might please a certain James May, the circuit itself actually still makes money, so someone must want it. Potential buyers are being wooed this weekend.

At twenty to five, the fastest group starts its formation lap. So far, no rain: the sky is still bright and it's a dry kick-off. As the field turns onto the old circuit, the second group leaves the start/finish line, followed in turn by a third. One hundred and seventy-five racing cars are now on the Nürburgring circuit.

Flares begin to rise from the forests. Ten minutes into their tour, the leaders run through the aptly-named Angst Kurve, then Klostertal, and round the Karussell, making noises that cars make nowhere else on earth. With the lead cars in the wilderness, the umbrellas go up in the grandstands. And then... the rain. Right on worst-case schedule.

Ferrari has never won this race, nor has Mercedes. BMW, Porsche and Audi have won the last three races respectively, and the Aston pit thinks this could be their turn. Sir Stirling Moss, James Bond and Aston CEO, Dr Ulrich Bez have joined us. Bez has his helmet: the avid racerwill do a few stints in the hydrogen-powered Rapide, and has pushed the effort since day one.

David King shares his chairman's excitement. "We could have put this technology in a road car and done some test drives in the USA, Europe or Dubai, but what would that prove? This place is the ultimate test of a vehicle, and is home to the only 24-Hour where we could race the technology."

Contrary to public perception of Germany, the Nurburgring has plenty of give in its rules. If you can prove the car is safe, you can race. Aston and Alset had a big job convincing the FIA and Germany's motorsport governors that a hydrogen car would be safe to race, but with detailed research, modelling and crash testing, they eventually got the thumbs up.

Fraser Dunn is the hydrogen Rapide's race engineer, and has managed engineering and testing from Aston Martin's side on the car with race number 100. "When David came into the office and asked me to lead this hydrogen project, my first thought was a German word. Hindenburg. Classroom experiments showed all of us kids how fast this gas burns, so I couldn't imagine a less safe fuel to race with. Alset's guys had all the answers."

"Hydrogen burns very well, releasing zero carbon plus water, which makes it the best choice for fuel," says Thomas Korn, Alset's resident physicist, recruited from BMW's fuel cell programme. "It is also the lightest of molecules. When petrol escapes in a crash, the liquid soaks into and covers material. Hydrogen just floats away, but the aim is that is does not escape."

The Rapide uses tanks made in Canada, with aluminium inner skins and a carbon fibre exterior. The sandwich tanks have incredible strength: a square inch of material from the tank's weakest point can withstand more force than three-foot-thick concrete. Add gas under pressure and the strength increases. These tanks take some serious breaking, but thereal test is the race.

The formation lap continues. Rain is still falling in the pits as the cars approach Döttinger Höhe. RadioLeMans.com reporters talk of rain on the long straight, and all predict Pedro Lamy will go for broke, to lead the first lap in the 007 Aston. As the water still falls, will these first sixty cars stop for wet tyres, or try for a first lap on slicks? It's a long way to go on dry rubber in rain.

One minute later, the question is answered. Grid one blasts beneath a waving green flag and the Aston makes a move down the outside. The canny R8 Audi holds its line through turn one and begins to stretch a gap. Marco Holzer's fourth place Manthey Porsche slips up to third. The cameras cut to a McLaren grenading, and an Audi TT in the pit lane for tyres.

The camera flicks back to the track. The Mamerow Audi R8 is moving on Holzer, when something goes bang. In a big way. By the time it returns to the pits, the Audi‘s adrift, down in 33rd place. The number 1 Audi hustles past Manthey Porsche: this race is most definitely on.

Within two laps of the start, the lead group catches the backmarkers and the Nürburgring carnage begins. Being passed by the world's most committed pro drivers in full attack mode scares the bejesus from amateur pilots, so part-timers have to know their stuff.

How exactly do you get enter this race? All drivers running the N24 must have completed at least two VLN Nürburgring championship rounds before getting an entry, and rightly so. If you've driven at speed on an Autobahn, looked away to check your side mirror and looked back to find a supersonic S-Class up your chuff, then imagine caning an old M3 around here flat-out, glancing away and then back, to see a blitzkrieg GT3 race car behind you. The tenuous thread of amateur concentration is easily snapped by a front-running car, closing at speed. Once that goes, your nextdestination is scenery.

A Union Jack-roofed BMW ends up stuffed in a barrier, bringing out the yellow flags. Further around the circuit, a Clio-shaped pinball bounces between armco flippers, as it attempts to exit the path of the leaders. The succession of caution flags compresses the lead group: Lamy in Bulldog 007 sniffs opportunity and hounds the Audi harder than ever, putting fresh air under his tyres as he leaps across the Flugplatz crests.

Le Mans has some speed, and track days at Sarthe are always a favourite, but doesn't compare to this madhouse: real elevation, the light and dark forests, scary-skinny Tarmac, Oh, and the relentless rain.

A Merc SLS pits for fuel just five laps in, with the leaders still thrashing around. Hard to see a Merc win if this is as far as they go on a tank, but you just never know at the ‘Ring. Fuel economy can make or break an endurance car, and this is part of the deal with Rapide: to validate hydrogen tech and really test the limits.

Along with the petrol cell, four tanks carry the Rapide's hydrogen: two in the boot, and two in place of the passenger seat. The tanks carry 3.2 kg of gas: enough to run flat-out for almost two laps. Each nine-lap stint will have one run solely on hydrogen. In hybrid mode, adding ten percent of petrol to the gas lifts power to ninety percent of petrol alone. Impressive.

To replace power lost by burning the less dense gas, Aston added a pair of small turbochargers. As this gives 600-plus horsepower when running all-petrol, the manufacturer has limited output to standard car levels by means of a custom ECU, complying with technical regulations.

Hydrogen releases more heat when it burns, making thermal management critical. Airflow through the front was optimised, welds on the exhaust manifolds were strengthened and Alset added the gas fuel injectors. Overall alterations to the production car are minimal: David King estimates that the full hydrogen package adds just 80 kilograms to the basic race chassis.

One hour in, the Audi still leads, 007 has pitted from fourth, and the hydrogen Aston Rapide lies P166. The hydrogen hybrid will win its class - it's the only car in it - but number 100's event is not for position: it just has to get to the finish. A split power steering hose and snapped bonnet pin have pushed it down the order, but spirits are high. The car is running well and staying out of trouble.

Night falls and the carnage continues, as an E36 M3 explodes through a gravel trap, entwined in a bent Renault Clio. Around the dark Nordschleife, the rain falls in earnest and it's all getting messy. Fog creeps from the forest, visibility sinks and floodwaters gather at high speed corners. The führers throw the red flag.

At 08.30 next morning, the race restarts with an interrupted rhythm. Aston 007 sinks down the field and the former leading Audi runs out of puff. Scotland's Peter Dumbreck in the Falken Motorsport Porsche 997 shows his class, making up places and reaching P4: "If only I had six Peter Dumbrecks for my drivers," as his Opel DTM team manager used to say.

The morning grinds on, and Aston 100 gains more and more airtime from TV cameras charmed by its elegant reliability. Porsche's hybrid from a few years back carried more duct tape than B&Q by the finish, but all the Aston will need is a wash. In truth, this project is different: the Porsche was trying to win it, but the Aston Rapide S is just here to demonstrate lap after lap of the Nürburgring while creating zero carbon emissions.

With an hour left to run, we watch the final hydrogen refuel at the Linde truck -topping up prototypes since 2006 - and decide to make tracks for the ferry. The race result looks settled, and the Rapide S has made its significant point. As we exit the circuit, the beach buggy passes: driver sodden, but satisfied. I wave and he waves - we'll both be back next year.

Crossing the line into Belgium, the clock strikes five, and an SLR crosses the line into history: first Mercedes to win the 24-Hour. The prototype Aston winds up P10: their powder will dry out for next year. Questions of winners now answered, one other question remains: what next for hydrogen?

"This was the technical validation," says Nacio. "We've proved the technology works. Now comes commercialisation: working with global partners to clean up our air and bring a new understanding of energy." Can the Alset team do it? Right now, it looks distinctly possible.