Thinking inside the box
Massive computing power allows a British company to streamline and test cars before they’re built, and even drive them virtually
By Gordon Cruickshank
Success has been heading Acura’s way in the ALMS sports car series. Good news for Honda, parent of the Acura badge. But racing is always about teamwork, and Acura has a significant but unsung team-mate here in Britain. You don’t see the Wirth Research name on the Acura’s flanks, but this young Bicester company has been crucial to Acura’s success, not only in the ALMS but also in the
past few years of the IRL.
Driving force behind the firm is Nick Wirth, who started out as an aerodynamicist with March and Leyton House and became chief designer at Benetton. In between, he founded and owned the Simtek F1 team. The connection is relevant; Simtek stood for Wirth’s firm Simulation Technologies, and simulation is the core of Wirth Research’s activities.
Tall and tanned, looking younger than his 42 years, Wirth talks with passion about how Britain is losing its technological leadership and how he wants his company to help regain it. This is not traditional patriotism: the Wirth office walls are lined with huge photos of British rock heroes. Wirth himself is plainly excited by recent proof he’s going the right way – the company has just received the Queen’s Award for Industry.
Until this meeting Wirth has been in a cleft stick. Brought in by Honda Performance Developments, which builds the 3.4-litre V8 engines in the US, to maximise IRL results, the firm extracted large improvements from the Dallara chassis, bringing the championship for Andretti-Green Racing in 2004, and both title and Indy 500 victory in 2005. The kudos, though, went to AGR and Honda – a situation Nick Wirth completely accepts. But now, after four years of quiet partnership, the Japanese firm is allowing Wirth to wave his own flag.
When Honda decided in 2006 to get the Acura name into sports cars, with Andretti-Green, it sent a Courage chassis to Wirth to see what they could do with it. The much-revised result, the ARX-01a, scored a 1-2-4 in the LMP2 class in its debut race at Sebring in 2007; Honda was so pleased it told Wirth to start on an all-new car.
Honda prefers to work with several existing teams rather than build its own, so Adrian Fernández and Gil de Ferran now run ARXs too. However, it’s Duncan Dayton’s Highcroft Racing which has the tightest connection, as lead pilot David Brabham is Wirth’s development driver, spending as much time in Bicester as Connecticut. When we meet at Wirth’s modest base he is fresh from a class victory at Long Beach.
Several iterations have resulted in effectively an all-new car, the current ARX-01b – front row on its first outing, class win and podium places under its carbon-fibre belt, potential winner overall. So where’s the story? Team builds fast car – it happens all the time, no? Not quite; the entire aerodynamics were designed and tested virtually. There were no wind tunnel models, no mock-ups before this car ran: the design was signed off digitally before any carbon fibre mat was cut. For Wirth’s business is virtuality.
That it fulfilled its designers’ expectations so closely confirms that virtual development can accurately mimic the real world. This is the core of Nick Wirth’s message: digital development can help you win, and save the planet too.
There are three prongs to this: CFD (a wind tunnel in a computer), 3D visualisation or virtual reality, and an innovative moving-platform racing simulator. We’ll start there.
Simulators are increasingly common, and those used by Formula 1 teams are extremely sophisticated. Those, however, are fixed to the floor, which means there’s no sense of motion (though Red Bull is rumoured to have a motion sim). Wirth has adapted airliner flight simulator technology to offer the first racing sim with three-dimensional movement. Getting to it involves a startling scale shift: open a door from an ordinary corridor and the roof suddenly soars, pulling you into a room dominated by a towering 20ft high mechanical presence, a pod perched on three sets of gleaming metal legs. It’s like discovering one of Wells’ Martians hiding in a garage. With a loud hiss the legs extend and the pod begins to rock, nodding and tipping in a crazy metallic dance which ties in with the race-engine audio track: on full-throat acceleration the pod leans back; through barking downshifts it pitches forward, before tipping sideways in a controlled lateral plunge. Inside, David Brabham is doing a demonstration lap of Silverstone.
Fifteen feet below sit technicians in front of screens which show what Brabham is seeing and doing as he goes for a lap time. One of them is Mark Herd, son of McLaren and March designer Robin, and now Wirth’s head of performance and race engineering. He tells me that simulator times accord closely with a real lap, so a session in the pod does help a driver improve his lap, including all the real-life tweaks – damping, weight distribution, geometry, even weather. The difference here is the sensation of g-force and the shudder of thumping kerbs. The machine can’t exaggerate gravity, of course; its theoretical maximum of 1g is shy of the 2g or 3g a real car generates, but the device compensates in several ways, for example by pulling the harness tight in braking and loading the steering in turns. And, says Mark, if you turn the motion down to zero – like a static sim – drivers tend to be slower, because they lose the physical feedback.
What’s rare is that time in this machine is now available to any team, as it can simulate sports, GT and GP2 cars as well as F1. Wirth tells us that two Grand Prix teams are already using this simulator, but then shakes his head with a little smile – no clues to who they are… But this is the only way you can get in practice laps of, say, Singapore ahead of time. It also allows teams to assess new drivers, or, because it can run multi-car scenarios, practice yellow-flag strategy.
In addition, as part of his mission to boost ‘UK Plc’, Wirth has donated sim time to the MSA Elite scheme, steered by Brabham, which nurtures promising young British drivers.
We cross the road to get to Digital Flow Solutions, the CFD section of Wirth. CFD? Computational Fluid Dynamics. Put simply, an on-screen wind tunnel – silent, quick and relatively cheap to run, once you’ve invested in a computer with a brain the size of a planet. Darren Davies, engineering manager of DFS, explains how in four years their computer power has expanded logarithmically and is now ahead of some F1 teams. The evidence is downstairs – a tall black cube with a column of smug-looking flickering blue LEDs.
Remember ‘Pong’ – the earliest computer game where you watched a single ‘ball’ bounce slowly back and forth? Now imagine tens, thousands, millions of similar virtual particles all rushing across the screen, interacting with each other and any fixed object in their way. That is what happens in the CFD machine’s processors – a continuous moving 3D model of the airflow over any virtual object you choose to create. It doesn’t quite replicate individual molecules of air blasting over a virtual car, but it does work on a tiny scale: the smallest ‘cells’ can be half a millimetre across. Or, as Darren puts it, you can have 8000 cells in one cc of virtual volume. That means that testing wings is child’s play for the system; it can also model fuel slosh inside the tank, oil surge in the engine, or the airflow through the car’s wheels at 150mph. In addition you can picture these flows at tiny intervals, down to 1/1000th of a second, and even model different temperatures to see whether a component will overheat. This allows the designer to minimise drag-inducing cooling vents.
F1 has woken up to the enormous energy costs of wind tunnels, which GP teams often run 24 hours a day – and some already have two tunnels. But on top of that is the unending waste of components which are manufactured, tested, found to offer no improvement – and dumped. Carbon fibre and titanium parts which take days or weeks to make are regularly thrown away – “£10,000 a day,” claims Wirth. Virtual testing simply sidesteps these materials and energy costs as well as slashing the time: Wirth estimates that CFD involves half the time and a quarter of the cost of real tunnel testing. On top of this, CFD has one ability tunnels can’t offer: running two cars and investigating wake effects, a function pioneered by Wirth. In today’s racing this has huge significance for overtaking.
Of course, F1 teams have their own CFD facilities; what’s different here is that Wirth is selling access to this immensely powerful technology to sports car and touring car teams who haven’t previously had this option. It works equally well for trucks and aircraft, and you can ‘thicken up’ the flow to replicate water. Recalling Wirth’s drive to see Britain back on top of the sporting podium, the words ‘America’s Cup’ were being mentioned...
There was one other element to explore, in a third unpretentious building. Virtual items on screen seem impressive – until you’ve been immersed in the ‘reality’ of a VR helmet. For this I was led into a large room, empty except for a small desk and a computer. Empty, that is, until I don a helmet with a tiny screen in front of each eye. Suddenly there’s a car in the room. A complete, detailed vision of the ARX-01b – and I can walk round it. Not only round, but through, slicing through the side to the cockpit to see the driver’s view, then watching ‘carbon fibre’ part like water as I wade through the monocoque. And this is not just a shell: the entire 3D structure below the skin is present.
I bend to look at the suspension, to be told it’s been blanked out for security. Instead I poke my head through the rear wing, seeing the aerofoil cross-section and even the little strengthening fillets inside. The shock of taking the helmet off and finding yourself back in an empty room is like stepping out of the wardrobe and wondering where Narnia went.
Novelty aside, VR allows designers to prove the 3D relationship of components before assembly, checking cockpit layouts and avoiding linkages fouling bulkheads. But in some ways the helmet experience is an extra. The real powerpoint is the computer model of the car, with all elements fully formed, ready for transfer to CNC machines or mould formers – or for testing in the sim.
Wirth’s deal with Honda runs to 2011, but Nick is realistic enough to recognise that success can be risky too, if you have one main partner. “The car could lose all its races, in which case Honda would quite rightly dump us. But we might win everything and have Honda say ‘well, we have nothing left to prove’, and pull out on the crest of a wave.” With the large investments needed to keep the CFD in particular up to speed, Wirth needs to know that there will be a wider income stream. This is why he wants all his behind the scenes work to become public, to attract a new spread of customers.
But they have to be serious contenders: “we turn down clients if we don’t think we can win with them”, he says. This is a firm concerned with results, not image, and its buildings certainly look no different to any others on this industrial estate – the same estate where Wirth began his career with March.
“I’m not interested in the bells and whistles,” says Wirth – an unusual view for someone who has been an F1 team owner. “I just want to see Britain back on top.” Maybe it’s time for the backroom boys to come forward.