Ultimate test

Windshear’s rolling road can be accelerated from zero to 290km/h in less than one minute

However, Windshear is located less than 50 km along Interstate-85 from Charlotte, the centre of the world’s most successful motorsport, NASCAR, and its owner is Gene Haas, who has his own NASCAR team, Haas CNC Racing. Haas’s team will no doubt be making use of the new $40m facility but he is keeping the wind tunnel business at arms length. It is being built and operated by Jacobs Technology, which, in turn, has hired Bordner.

With the NASCAR economy worth an estimated $22bn a year, Bordner is aware that any team using Windshear requires the strictest security and confidentiality. ‘There are three secure preparation rooms to which only the customer on the day will have access,’ said Bordner. ‘As far as data collection and security goes, we were originally going to send all the data straight to the customer’s computer but their comments have prompted us to make a small change. We will now keep a copy of the data on our server. We’ll give them a set of data DVDs and, when they sign them off, we’ll remove all the data from our servers in a way which will be transparent so that the customer can verify the action.’

Bordner expects that initially Windshear will have enough customers to keep one 10 or 12-hour shift running each day, although the facility has the potential to operate continuously. Maintenance downtime will be scheduled. ‘We have a pretty detailed preventative maintenance schedule to avoid any unplanned downtime,’ he said.

While Windshear is expected to be the first full-scale, high-speed, rolling-road wind tunnel in North America, it is unlikely to have the field to itself for long. Barely 30km up the road, in Salisbury, North Carolina, another consortium has plans for something even bigger and better.

Wind Tunnel Extreme(WTX) is planned to be the most advanced such facility in the world, with the ability to have up to three cars on the rolling road at any one time.

Kristen Helsel leads the $70m development. ‘We’ve been planning it for about 18 months,’ said Helsel, a mechanical engineer who spent almost a decade with GM before setting up her own sports marketing business and running the Swift wind tunnel.

‘I travelled the world looking at the best wind tunnels and I discovered that the United States was woefully behind any type of offering that Europe and Japan had.

‘And so I realised there was this huge need for a wind tunnel of this kind, [not only] for racing but also for the automotive industry. Both industries are vital to the economy, so it is important for an instrument of this calibre to be available to various automotive companies and motorsports entities to have the ability to do this type of testing. It’s applicable not only to racing, but also corporate average fuel economy and things that are going to be pressing the car industry for years to come.’

The business model for WTX differs from Windshear’s. Helsel is recruiting members — raceteams and other automotive organisations — that will each be entitled to share in the tunnel’s operating time. She claims to have sold almost half of the time already.

Unusually, one member has revealed its identity — Toyota Racing Development (TRD). ‘Toyota and TRD plan to be part of the NASCAR community for a long, long time,’ said Lee White, senior vice-president and general manager of TRD USA. ‘We are building an engineering facility and technical centre in the Charlotte area to focus on chassis design, development and research.

‘However, another key component to the success of our NASCAR programme is the availability of wind-tunnel time. Our commitment to this programme should alleviate that issue and provide us with an exceptional facility to utilise.’

One remarkable factor that helped sway TRD was that WTX will be big enough to accommodate three cars at once, in line or offset by up to 50 per cent, to more closely simulate the situation on a racetrack. To achieve this, the test section of the tunnel will be 26m long by 5m wide and 2.6m high. The company has not released any specifications for the rolling road or the airflow system except that the latter will have walls whose profile can be changed to match the aerodynamic characteristics of the vehicle being tested.

As air blows over the vehicles, pressure sensors in the walls detect a pattern that would produce the ideal tunnel shape. Panels then move into the ideal shape to conform to the model’s airflow and eliminate aerodynamic interference in about one minute, to create a more accurate flow field around the car, eliminating pressure gradient through the length of the tunnel and allowing better calibration of sensors to track data.

Both Windshear and WTX are buying their rolling roads from MTS Systems Corporation of Minnesota, US. The global engineering testing company is the market leader for rolling roads of all sizes, claimed its marketing manager Jake Rawn. ‘As far as sales number go, we’re in the mid-teens right now for single belt systems and we’ve done three of the world’s five-belt systems,’ said Rawn. ‘The single belt provides a complete, unbroken moving ground plane while the five-belt has a belt under each wheel and another the length of the vehicle between the tyres.’

While each design has its benefits and shortcomings, WTX is investing in a proprietary MTS system called Talingz to remove the effect of the restraint struts from the total drag number. Talingz is said to allow the separation of rolling resistance from drag measurement in a full-scale configuration and provide a higher fidelity measurement of drag, yaw moment and side force than measuring through the struts.

WTX is scheduled to be fully operational in a year but by then it could have been overtaken by yet another rival. There are plans to add a full-scale, high-speed rolling road to the fourth largest wind tunnel in the world, inside the former NASA Langley wind tunnel in Hampton, Virginia. It may be almost 600km from the centre of the NASCAR industry but that does not deter Old Dominion University, which has been operating the tunnel since 2005.

According to the tunnel’s operator, a single-belt, rolling-road system from MTS, 7m long by 2.4m wide and capable of a top speed of 290km/h, is on its way by the end of this year, to be mounted on a turntable which has a yaw range of 10 degrees. The Engineer has tried to ascertain the status of the project but university representatives will not comment due to ‘political sensitivities’.

This reserve is characteristic of those involved in full-scale, high-speed rolling roads. ‘We’re still not releasing a lot of information about the guts of our technology, about how we track and steer the steel belt,’ said Jake Rawn of MTS. ‘It’s a bit of magic, an ability that’s been a core technology of MTS for 20 years.’

It’s a clever trick that Rawn believes will attract yet more customers as full-scale, high-speed rolling roads become an accepted part of the automotive landscape. ‘There’s not been a single motorsport entity that has built a rolling road without involving MTS since the late 1990s,’ said Rawn. ‘The market has grown recently in the US. In other areas of the world, Europe and Asia, we’ve seen them used by motorsports through to auto makers and component makers. It seems reasonable that we’ll see a similar trend in the US.’

Now that NASCAR teams are realising there’s more to track racing than top-quality showmanship, technology testing facilities will be in greater demand.