Probably the only car on the grid not significantly influenced by last year’s Ferrari, the W09 stays with the W08 theme of long wheelbase (identical) and low rake, though the team says it will have slightly more rake than before but nowhere near Red Bull level. The low nose is an intrinsic part of the low-rake concept in that the small gap between nose underside and front wing neutral section will accelerate the airflow (despite reducing the capacity). This and the intricate and powerful under-nose vanes are all about compensating for the lower expansion area of the low-rake floor. Because there’s less underfloor low-pressure effectively sucking the airflow towards it faster, the nose and vanes are used to accelerate it ‘artificially’ instead.
Mercedes has stayed with the very high upper front wishbone, mounted on a lug extension from the upright, but probably even higher than before. The sidepod openings are slightly higher than previously. This has allowed more sidepod undercut. To get adequate flow to the radiators there’s a dramatic-looking longitudinal vane atop the barge boards, picking up air from below the upper wishbones and guiding it to the inlets. The sidepods themselves are much wider than Red Bull’s (or Sauber’s), slightly wider than Ferrari’s. The rear radiator outlets are significantly bigger than before.
In plan view – with the Mercedes split turbo layout – the engine is slightly farther back than on Renault/Ferrari-engined cars and so there’s not quite as big a coke bottle, though it’s significantly tighter than the W08’s. The front halves of the pods are bulkier from above than those of either Ferrari, Red Bull or McLaren.
Like the cars of the Mercedes customer teams, the W09 features an all-new engine to the same basic concept, which wouldn’t have been possible under old token system. A lot of attention has been paid to getting c of g down to counter effects of the halo and of the higher radiator openings. One wonders if, for example, Renault Sport has been able to devote as much resource to this aspect of its engine while still trying to achieve performance and reliability.
The design has not followed the Ferrari-inspired trend of separating side crash structure from sidepod and continues to be incorporated – perhaps because there’s more space available from front axle and therefore better aero efficiency.
A lot of attention has been paid to suspension kinematics: the rear wishbones are mounted well outboard of the wheel and are very long.
High nose tip (Toro Rosso, below) vs low nose tip (Mercedes, above). Mass flow capacity vs air speed. As a generalisation, the high nose creates more capacity to feed a high-rake underfloor. The low nose induces greater air speed at that point and is well suited to feeding a low-rake floor, which isn’t accelerating the air as hard as a high-rake floor