F1 Tech Talk: Toro Rosso’s double floor

If Formula One gave awards for radical design Toro Rosso’s STR6 would have a full trophy cabinet. Chief designer Ben Butler talks us through Faenza’s latest creation.

After 10 years of stability F1 has for the third time in three years ushered in a fundamental change to its rules. Inevitably it’s led to some extreme interpretations of what an F1 car should look like and the one that really has tongues wagging is Toro Rosso’s STR6, brainchild of chief designer Ben Butler. Ben explained to us why the new car is as it is.

Ben, people are talking about the STR6 having a ’double-floor’ – what does that mean?

BB: “We prefer to call them ‘extreme undercut sidepods’. It basically means we raise all the hardware that would normally be housed in the floor and sidepod area and clear a path to the rear of the car. It sounds easy but the installation has to change a lot in order to adopt the concept. The result is an uninterrupted pathway for the air to the rear of the car without having to go around the sidepods.”

There are a couple of other teams doing unusual things with their sidepods this year. Are they trying to achieve the same aim?

“I can’t speak for them but you can see that many teams are doing quite different things at the rear of the cars.”

Is getting new diffusers to work efficiently the most important technical challenge for designers this year?

“I think all teams have had a lot of challenges to deal with this year. The return of KERS has meant most teams are learning the difficulties of adopting the system and its effect on braking from the KERS charging. The weight limit [for car + driver] is now 20kgs more than it was last year but I think a lot of teams are finding the KERS package weighs more than that, so general weight reduction has been necessary.

“The weight distribution is now regulated with 45.5-46.5 per cent at the front, so not only are you adding weight, you have got to put it in the right place, then comes the Actuated Rear Wing which everybody has to get right otherwise you lose a lot of performance. On top of that there are new chassis regs. The list goes on and on. But yes, a huge performance loss has been the banning of the double diffuser and also the height of the diffuser that remains has been reduced. It’s an area that has required a lot of attention in the wind tunnel to claw back the kind of performance the cars have become accustomed to having.”

Ferrari tried this approach a long time ago (the 1992 car), has something changed in the regulations that makes this a good idea again?

“Again, it’s the banning the double diffusers that have made this concept more appealing – but a lot of other things have changed since 1992. Back then you had no stepped floors, huge expansions for the diffuser and 12 cylinder exhaust systems. “

If the advantage is it allows air a clear route to the rear of the car, what are the disadvantages?

“Disadvantages are that there are more parts of the car higher up. Racing cars generally want to have a low centre of gravity, so that’s not great, but the effect is not huge. The bigger penalty is the extra weight. The surface area of bodywork as increased, and we now have large sections of overhanging bodywork. Before, they were efficiently supported, but now to get the same level of stiffness it’s inevitable that we have to add weight. However, we knew that at the start of the project and all the guys have done a great job in reducing the core weight of the car by around 20kgs. We would not be running KERS if we hadn’t got the weight down.”

Has it made radiators etc., more difficult to package?

“The installation has been a tough one, especially the exhausts. Our exhaust designer must be on his 65th iteration of exhaust at the moment and even he is getting tired of looking at pipes all day. But this is a critical area that all teams are exploring this year. With the undercut sidepods it makes things a bit harder and this has taken a while to get right.”

Will it make the car more difficult to drive?

“Not Intrinsically, no. The car is more difficult to drive because now we have KERS affecting our braking, we have a rear wing to operate, the driver cannot adjust the front wing on the track anymore so it’s difficult to get the balance – but these issues are not linked to the undercut sidepod concept.”

Provided by ToroRosso.com