Australian GP : technical news part 1

Williams FW31 - rear diffuser design



Like engine suppliers Toyota's, Williams' interpretation of the revised diffuser regulations is highly innovative. Much of the diffuser's central section is actually lower than the outer sections. However, clever shaping of the rear crash structure immediately below the rear light effectively creates a second central section (red arrow). In combination, the result is a central section that exceeds the 175mm height allowance that applies to the diffuser alone.

McLaren MP4-24 - cut-out rear floor




McLaren have introduced something completely new for 2009 - a floor with a cut-out section in front of the rear tyres. Its aim appears to be to increase the effectiveness of the rear diffuser by effectively turning the whole rear bodywork area into one large diffuser, with the 'throat' of the venturi starting just ahead of the back wheels. The delta-shaped leading edge of the cut-out creates low pressure, encouraging the diffuser to pull in more air at a faster rate. This solution is possible because with no more flick-ups (banned for 2009) on the upper bodywork, it's no longer essential to retain the uniformity of the lower floor area. It remains to be seen whether this is a pro-active measure from McLaren, or a reaction to a general lack of downforce.

Williams FW31 - vertical 'skate' fins



With the 2009 regulations bringing so many changes, teams are inevitably investigating every avenue in a bid to find potentially beneficial loopholes. Williams have utilised this area immediately surrounding the cockpit - an area unrestricted by most bodywork regulations - to add new vertical fins, dubbed 'skate' fins because of their resemblance to the flat fish of that name. They utilise similar principles to the 'horn' wings employed in recent seasons by McLaren and BMW Sauber on the side of their engine covers. They interfere with airflow, redirecting it more effectively towards the rear wing, hence improving the wing's efficiency. Sauber used the same idea in practice for the 2006 French Grand Prix. However, their fins were sited on top of the chassis, level with the front suspension, and fears over their effect on driver visibility meant they were never raced.