Tech Analysis: Williams FW30

With the move to Bridgestone tyres in 2007, Williams seemed to get the bias right, producing a low-drag car with a good weight distribution.

The changes in design emphasis led to an "upswing" in performance, according to Patrick Head. The foundations built for 2006 should reap rewards in 2008, as the team has a good aero platform and mechanical layout.

When it first appeared in testing, initial impressions were that the car was largely unchanged for 2008. There were a few obvious updates around the sidepods, but largely it appeared to be the car the team ran in late 2007. Yet as testing has progressed, several new features and one innovation have emerged.

One of the team's aims was to refine the weight distribution. This has been achieved without recourse to wheelbase alterations, although Williams hasn't said whether the layout within the 3100mm wheelbase has altered.

As well as working on the basic factors such as weight and aerodynamics, the team has also set its focus on quality. The team already had a good reliability record in 2007, but the failures that did occur were mainly related to small ancillary parts.

Sam Michael said the team was "designing a tidier car with a higher standard of build quality" to remove any remaining doubts over the car's reliability.

Reliability is also a key factor this year for the gearbox, which now has to last four races. This year the team is splitting from Toyota in developing its gear cluster and electronics. The gearbox, in its aluminium case, has been updated to meet the new shaft spacing and gear width rule, as well as the additional development to ensure the bearings, shafts and selection mechanism will last the extra distance.

Williams's new triple plane front wing is matched with new nose fins (yellow) © Scarborough (Click to enlarge)

Externally, the main changes to the car are the front wing, sidepods and diffuser. This balance of changes suggests that Williams is seeking an overall gain in grip, rather than simply recovering the downforce missing from last year.

Up front, the team has developed a new wing. The smoothly-swept wing sports three elements, although it is hung conventionally from its front element rather than McLaren-style, from its middle flap.

One unusual feature of the wing is the downturned ends - usually, the outer tips of the wing are raised to reduce drag created at the tip. Perhaps offsetting this change is the much shorter chord of the wing near its tips.

Allied to the new wing is a lower nose. Williams was one of the first to adopt McLaren's bridge wing last year, with a flap featuring a rather abruptly curved bridge section. This year's nose is lower and shorter, and allows the bridge flap to be more gently curved.

Aiding the bridge wing are new nose fins attached to the nose cone. Like several other teams, Williams has used the maximum width allowed for the fins and then added the TV camera on the end, making the device wider than otherwise possible, but still within the rules.

Although the camera is of a fixed teardrop cross-section it can provide a small aerodynamic benefit along the with the fins in flattening the flow coming off the front wing before it passes over the rear of the car.

In testing, William suffered two front wing failures. These have been attributed to cracks in the mounting pylon. It was also rumoured that the additional vibration was caused by ballast being run in the front wing main plane. This is possible, as teams are known to run pockets for ballast in the wing.

The FIA frowns upon this practice and has asked the teams to limit the weight they add to the nose cone/wing assembly. It is known that around nine kilograms of ballast was run in the wing by some teams in 2007. However with Williams having worked to resolve its weight distribution, it's unlikely that it would still choose to run a lot of weight in the front wing.

For the first time, the Williams car has pod wings (yellow), which have been merged into the chimney © Scarborough (Click to enlarge)

Aside from the new higher regulation cockpit padding, the main changes in the middle of the car are in the sidepods. While Williams's was not the worst in the pitlane in 2007, Michael admitted that the team needed to improve its cooling solution: "We've put quite a bit of energy into that for the FW30," he said.

As a result the sidepod inlet and shoulder profile is subtly different, and the coolers are now mounted face-up. Also, Williams's recent trademark chimneys, with a large open-mouthed side exit, have been replaced with slimmer, McLaren-style affairs.

The pod wings on the front of the sidepods now merge into the chimney, which itself vents vertically. Also, the T-wing behind the chimney is now mounted on its own, and is no longer moulded into the chimney. Last year Williams often ran louvers in the top of the sidepods; these are rationalised this year, as broader slots moulded across the width of the sidepod.

There are also more cooling slots near the exhaust fairing, which itself is tucked in closer and further back down the sidepod than last year.

Above the sidepods on the roll structure, Williams has a uniquely-shaped mid wing. The profile sports a swept-back shape, appearing like a flattened version of McLaren's viking wings. Most likely their similarity reflects a similar purpose - to send a trailing vortex to the rear wing when the car is yawed, ensuring the rear wing works even when the car is at angle to the oncoming airflow.

Behind this, Williams has maintained a similarly-profiled engine cover to that used last year, but it has further slimmed the upper position of the cover as demonstrated by the much larger strake added to meet the dimensional rules.

Beneath the undercut in the engine cover spine, Williams has added a cooling outlet to vent both a small radiator and the sidepods. Putting a cooler and exit area above the gearbox removes some of the cooling demand on the sidepods, with in turn allows the sidepods to be slimmer.

However the biggest change is the diffuser, which Williams has further exploited in a new way for 2008. Starting with the FW29, Williams has followed Ferrari's path and opted for a high expansion diffuser.

By diverging the diffuser into the beam wing, Williams have the largest possible diffuser © Scarborough (Click to enlarge)

This makes the most of the allowable area between the rear wheels for the diffuser, and as a result the Williams has the small extra side channels and beam wing split to allow the central tunnel to rise up to the maximum height.

This allows the diffuser to be used to its greatest potential, as its exit area largely limits the downforce possible. However, this aggressive approach comes at a price, because the flow exiting the diffuser wants to separate from the diffuser's surface, creating drag and losing downforce.

In 2007 Williams countered this with detailed design and intricate vanes added to the rear brake ducts to keep the flow attached. Now, the team has further expanded the diffuser - the top of the central tunnel now widens into the area usually occupied by the beam wing, adding yet more exit area to the diffuser.

As yet, no one else has blended the beam wing into the diffuser roof, This approach is only possible because the upper rear wing is mounted on struts, allowing the beam wing to be semi-structural and hence more shapely.

Allied to the new larger front wing, it appears that Williams has found a drag-efficient way of adding rear downforce to balance it. For the other teams with high expansion diffusers (Ferrari, McLaren, BMW, Red Bull), this solution may take some time to develop.