2006 Brazilian GP Technical Review

After 18 rounds, the season reached its finale at the Interlagos circuit at Brazil.

Although the track has its challenges, overall it sits as a medium downforce circuit along with most other recent venues. With the teams having an eye on reliability to preserve their championship points - or some teams having stopped development to focus on 2006 - there was little development to be seen in Sao Paolo. In fact, most cars were in very similar specification to the updates first seen back in Turkey.

However, the drivers with a fresh engine for this race had a unique opportunity to have their usual two-race specification altered to last just one race. This meant drivers had more power and revs available for the weekend, and Cosworth for example had their engine duty cycle revised to allow the full 20,000rpm for the whole race, although the accidents for both Williams drivers prevented this spectacle in Cosworth's last race.

Interlagos is one of only two anti-clockwise tracks, and while this makes little difference for the cars, the drivers suffer more in the neck area - after already being wrought after a season of racing.

In layout, the track features two long straights; the main straight begins with a long sweeping uphill section before going downhill into the first tight chicane sequence. There then follows another straight, again ended by a tight turn.

These two features allow overtaking and also create the set-up quandary for the teams, as the remaining parts of sectors 2 and 3 are tight and twisty. This means teams the have to balance downforce to protect their tyres from graining, and low drag to allow a high top speed.

Additionally, the Brazilian circuit has bumps - lots of them, in fact, despite the resurfacing work carried out. This means the teams have to work carefully on ride heights and suspension set-up to bring grip, especially in the last corners of sector 2 to allow traction on to the straight.

McLaren's horizontal fin

A rare chance to see the McLaren up close has exposed this horizontal fin. This is not a new development, however, but rather part of the Turkish Grand Prix upgrade.

It is typical of the detail development going on around the front suspension. As with all developments, its aim is to direct flow off the front wing and aim it more accurately around the sidepods toward the rear wing/diffuser.

In this case, McLaren have opted for a thin section, while most teams use a larger flat plate. But all take the device's width to the maximum allowed in this area.

Ferrari's sprung floor mount

At first, the appearance of a sprung mounting for Ferrari's front splitter was alarming, once again raising the spectre of flexible aerodynamics. But this feature is not unique to Ferrari and is known and accepted by the FIA. The splitter's installation is not to gain aerodynamic advantage but to make sure the exposed splitter is not damaged when contacting the ground.

The front splitter - or shadow plate - is the flat section protruding underneath the raised part of the chassis. Legally, this part is required to meet the flat bottom regulations. Technically, the teams use this component to split and direct the flow around the floor and sidepods.

Ferrari, along with other teams, use a sprung mount (yellow) to protect the vulnerable splitter © Scarborough (Click image to enlarge)

As the front section of the chassis has been progressively raised by the designers, this splitter is now very large and mounted on the reference plane, which is the lowest part of the car (plank excepted).

When front wings were allowed to be lower, teams running very low ride heights would let the splitter drag on the ground. This allowed the front wing to be even closer to the ground during braking, thus improving downforce. As this practice developed, the splitter was designed to flex upwards to prevent damage and ease the wear on the skid blocks.

Too much wear on the skid blocks is in contravention of stepped floor/plank rules and therefore would lead to exclusion from the results. In response, the FIA created a test that checks the splitter does not flex upwards, and this is routinely carried out on the FIA's scrutineering rig by a ram projecting upwards and measuring the flex.

As is usual with the FIA's flex tests, there is a maximum movement for a given load, and movement over or above that load is allowed.

As teams now make the splitter almost entirely from a tungsten alloy, as part of the car's ballast, they are obviously concerned for its security when going off track or hitting debris. Thus, the teams create a flexible mounting that will pass the FIA deflection test.

A second failure to the third damper set-up (yellow) caused retirements for both Toyota cars © Scarborough (Click image to enlarge)

The FIA is aware of the practice and is not as concerned, as the front wing ride heights are much higher nowadays and little benefit is to be gained from running extra-low ride heights.

Toyota's third spring

Toyota suffered the second occurrence of a rear suspension failure. The third spring/damper failed in both cars at Interlagos, as they did earlier this summer in Indianapolis. Failures of these components are rare, but a double failure is extremely unusual.

The third spring/damper is used to control the car's ride height for aerodynamic purposes. When the car's suspension is being loaded by downforce or unloaded under braking, the rear suspension movement is controlled by the third element. It controls both the rate of movement and the amount of travel. This prevents the diffuser being unsettles by large variance in ride height.

In Toyota's case, the third element is attached to a yoke that also connects to the car's anti-roll bar. If part of this set-up failed, the car would be left without any control of roll or pitch, making the rear of the car uncontrollable over gradients and bumps.

More updates for Super Aguri covered cooling with closed inlet ducts and a larger chimney (yellow) © Scarborough (Click image to enlarge)

Super Aguri's new chimney

Super Aguri had yet more minor changes, with both a new chimney and new brake duct tried in testing.

In preparation for the hot weather expected for Brazil, a larger chimney was raced. This chimney follows the same basic shape as the usual design, but being longer, it now intersects with the winglet.

This addition is a contrast to the smaller sidepod inlet adopted since China. This change came after the full "B" specification bodywork and suspension were adopted, and may have improved the flow into the sidepods, allowing for the smaller inlets. Perhaps the cooling limitation with the Aguri sidepod is on outlet area rather than inlet area.

Again, following common practice, the team also tried a fairing that encloses the front brake discs. This design is said to improve brake cooling by routing the flow out through the wheel more effectively.