Tech Analysis: Williams FW29

The 2007 season could not come quick enough for the people at Williams. Last year, strong pre-season testing form developed high expectations that the Cosworth-powered machine simply could not live up to. The season proved to be a real let down and the team hung their heads as a lack of pace and chronic unreliability proved impossible to hide.

Hide, though, is something that Williams do not do. The team's principal players openly admitted at last week's launch that their failures in 2006 were unacceptable and there was a clear cry of 'must do better' as the wraps came off the new Toyota-powered FW29, the car that must get the team back on track.

The now departed FW28 struggled with aerodynamic efficiency - the wings would produce downforce but at great cost on drag, slowing the car's top speed and hindering lap times. Equally, their all-new seamless gearbox and the car's hydraulics stopped the car all too frequently in races.

Their new car is substantially new and clearly represents a new direction for the team as they respond both to the problems of last year and the new rules concerning tyres and safety.

The recent run of cars from Williams have all had problems with their aerodynamics. In 2005 the full size car failed to match the wind tunnel expectations leaving it short on downforce and last year the car lacked the efficiency it needed, a problem again partly blamed on the correlation between the wind tunnel model and the car.

Side view © Scarborough (Click image to enlarge)

The way the team's two wind tunnels are operated was crucial in developing the new car and the team's technical director Sam Michael spoke exclusively to Autosport.com to explain the design process and discuss the car.

"A lot of things were looked at," he said. "It's just working away on load cells, measurement techniques and different pressure gradients through the tunnel. Also how the model is mounted inside the tunnel is important.

"We're working with the model to make sure that all things, such as cornering and what the tyre contact patch is doing, more accurately represent what happens with the full size car. We've made pretty big steps with that. It takes time and it's taken a lot of time to get it right".

With the ground work now complete, the two tunnels are used simultaneously and both the model and the actual car are tested. "On average we do a week of full-size testing in every six weeks," explained Michael.

After initial teething problems, experienced by any team that brings a new tunnel online, the two tunnels are now interchangeable. Work is now evenly allocated to each of the tunnels and Michael added: "You can put a diffuser or wing in each tunnel now and get the same results."

The aims for the new car were to reduce weight at the rear to allow a more forward weight bias and also to lower the centre of gravity. Aerodynamic aims were to reduce drag for the same downforce and on the mechanical side the reliability problems with the transmission needed to be rectified.

Rear view © Scarborough (Click image to enlarge)

In its layout, the FW29 differs little from its predecessor, aside from the gearbox being shortened slightly to allow larger fuel tank. The front suspension still uses a zero keel layout with the front bulkhead moved down, but only by five millimetres according to Michael.

Most of the changes are aerodynamic and mechanical, the latter being largely the revised seamless shift gearbox and the packaging to install the Toyota engine. The gearbox remains an Aluminium casting, something of which Michael is particularly proud.

Williams have completed projects to compare differing materials and Michael said: "Aluminium casings are lighter than carbon and titanium. We did a big carbon and titanium project 3-4 years ago, then titanium again about six months ago.

"We couldn't get it within half a kilo of the Aluminium one. The problems [with the other types] is the lead time and cost. We'd need to spend £350k more a year on gearboxes. Plus the lead-time is massive, its crazy and it doesn't make sense. For us the aluminium gearbox is the way to go."

The new aero work starts at the nose with nose cone, which is a little higher and with a more generous radius to its underside compared to its predecessor. The new front wing has yet to arrive, although the curved biplane wing will remain.

Above the shadow plate, under the raised part of the monocoque, the vertical splitter has been lengthened to the full length of the splitter primarily for ballast location, says Michael, but also aerodynamic performance.

The ability to house more ballast has been aided by weight savings in the Zero keel area of the monocoque and Michael said: "We're now two kilos lighter than with the single keel. When we started it was all metallic, with big inserts in the chassis. Now it's all carbon."

The bargeboards follow typical Williams thinking with a cluster of vanes inside the front suspension and a smaller board in front of the sidepods. These are aided by the large floor fin that leads back to heavily revised sidepods designed to meet the packaging requirements of the Toyota engine.

Suspension element © Scarborough (Click image to enlarge)

Williams wanted to keep the centre of gravity as low as possible, so the radiators eschew the fashionable horizontal tilted coolers for more conventional vertical coolers splayed out from the back of the chassis. Then, to keep the exhaust from blocking the tight coke bottle waist, the secondary pipe protrudes through the sidepod within a fairing.

With the closely coupled components inside the sidepods, the outer shape is now much cleaner, starting with an undercut at the front shoulder of the sidepod, as extreme as is seen on the McLaren and BMW cars.

Michael commented that an even more closed off inlet was tried, but this hampered engine cooling too much. The sidepods side profile is dominated by a typical Williams-style large side exit chimney. The launch version of the outlet was designed for the opening hot races but a smaller version will be run for the Spanish Grand Prix. Despite the chimney's size, it is aided by a run of louvers on the top surface of the sidepod just inboard of the chimney.

As part of the drag reduction criteria set for the car, the rest of the sidepod additions seen in 2006 have been deleted for the new car. Last year the sidepod featured a chimney-mounted winglet and a second winglet below that. The main flip-up had extra profiles moulded into it as well as a secondary flip-up beneath that.

This stack of components all aimed to gain downforce at the rear of the car but came with a cost of significant drag levels. This year the sidepods feature a simple flip-up and a winglet mounted into the chimney. Even the vertical elements creating endplates on the flip up and between the rear wheels have been slimmed for drag reduction.

Despite these visual changes being important, the greatest work has been done underneath the rear the car. Williams have sported a distinctive diffuser for several years, with the side channels being aided by small winglets. For the FW29, however, Williams have taken inspiration from the 2006 Ferrari.

By adopting two struts to support the rear wing, the loads that are usually taken by the endplates and lower beam wing are removed. This allows the beam wings shape to free up, as well as taking a large amount of weight out of the component.

Williams have split the beam wing in order to make the central diffuser tunnels as tall as possible and this is especially important as the rear crash structure regulations now demand the structure to be lower and hence sit within the central diffuser tunnel, taking up valuable exit area.

As well as creating more exit area with the split beam wing, Williams have also adopted the small extra channel sported by Ferrari; this makes their rear end as large as possible allowable under the regulations. Michael is proud of this solution and said: "I quite happy about that, it's a massive gain."

Cockpit © Scarborough (Click image to enlarge)

The rear end is also tidied up with new fairing around the drive shafts and rear brake ducts. These are now integrated to a single shape, the brake ducts swooping into the aerofoil section fairing around the driveshaft, which at its opposite end is moulded into the diffuser and gearbox fairing. This development was also quite a gain according, to Michael.

Williams are also happy to be working with Toyota and although the Cosworth V8 they ran in 2006 was an impressive unit they have already admitted the Toyota was a more powerful unit. Early testing did show up some additional cooling requirements and these have been incorporated into the new car - but this cooling concern has manifested itself in the overly large cooling panels fitted for the three flyaway races.

With such a new car, you could be forgiven for expecting troubles with the package. But Williams have worked hard to cross check their aerodynamics with on-track figures and the early testing of the interim car has proven the engine installation.

If the car does have the step in performance and reliability then a return to a more successful period is possible. Certainly comparing the Toyota chassis to the Williams, both with the same engine and similar gearboxes, the Williams appears to be the stronger more progressive design.

If that continues into the season, it will be interesting to see how Toyota might respond to an independent team usurping their pace despite lesser resources.