Will Gray

Tech Talk: Aero efficiency key to Silverstone success

Will Gray

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The high-speed Silverstone circuit puts a premium on aerodynamic efficiency — and that could be the biggest key to conquering this weekend's British Grand Prix.

The Silverstone circuit has changed numerous times in the last 20 years and evolved into its current specification in 2010. Throughout the years, however, success here has always been about mastering the set-up to cope with fast corners.

The average speed at the track is high — around 220km/h for a good qualifying lap - but it's not quite like Monza, where fast straights demand ultra-low downforce set-ups. At Silverstone, seven of the 18 corners are taken at over 250km/h - and that means the ideal set-up is not ultra-low downforce but ultra-efficient downforce.

The cars generate downforce from a number of different aerodynamic devices all working together — wings, end plates, barge boards, floor, diffuser; even helmet shapes make a difference. The aim for each downforce-producing part is to provide maximum downforce benefit for minimum trade-off in drag — and some parts are better than others.

The most efficient area of the car is the floor and diffuser — the downforce produced by this area is virtually 'free', in that it comes with negligible drag effect. Wings are less efficient and teams spend much of their time working on profiles to create different options that provide different levels of downforce.

The question is: whose car is the most efficient?

Red Bull's strength has always been acknowledged to be in high-speed aerodynamics — but that was mostly in the days of the blown diffuser. However, their new floor appeared to work wonders at the last race in Valencia and now at Silverstone it could have an even better effect as it increases the amount of efficient downforce they can produce from that area and enables them to reduce the demand for downforce from the wings, making it an overall more efficient package.

Mercedes, meanwhile, should also benefit in a different way — as this track should see them gain more than most from their 'double DRS' system. They are the only team who currently use a DRS system that allows them to shed the inefficient downforce (and therefore drag) from both rear and front wings — and although this is only particularly significant in qualifying, where they have free use of the system, it could be the boost they need to get on pole and control the race.

Williams could be looking good too, as Silverstone is a similar track to Barcelona and that is where they scored their first victory since 2004. After a few disappointing races, an upgraded aerodynamics package could put them right back in the fight.

The high-speed nature of the circuit also makes transient handling important, to handle the rapid direction changes in the sweeping sections of the track. This is partly achieved through aerodynamic grip but also by ensuring the mechanical set-up gives the driver confidence to attack.

While being fast through those sections is critical for lap time, however, it is also critical on tyres.

There are significant demands on the construction of the tyre in these sections — because of very high loads — but teams can cope with this by optimising camber and tyre pressures to avoid overstressing the construction.

However, the high-speed cornering forces also put high energy through the tyres and push up temperatures — so with the critical temperature range in which this season's tyre compounds operate, teams will need to quickly determine a set-up that allows the tyres to cope.

Having more efficient downforce gives greater flexibility here, because it allows teams to create extra high-speed grip without compromising straight line speed too much — and with more grip there is less slip, so that should result in less degradation in these areas.

None of the front-running teams have revealed their development plans for this race, but it is likely that most will bring modified wings in the pursuit of extra efficiency.

Behind the top group, however, Williams, Sauber and Force India have all promised major upgrades — and if any of those can find an efficient improvement then they could spring a surprise.

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