Brawn explains Merc slump

Ross Brawn believes changes to Mercedes' aerodynamic department played a major role in their 2012 slump.

The Brackley squad looked like they would challenge for several race victories in 2012 after Nico Rosberg won the Chinese Grand Prix from pole position.

However, it was a false dawn as they could only manage two more podium places in the next 17 races and finished a distant fifth in the constructors' championship.

Brawn, though, feels that the departure of head of aerodynamics Loic Bigois, changes to their windtunnel philosophy as well as experiments with the Coanda exhausts and double DRS were to blame for their inability to challenge at the front.

"We made a decision to change the structure of the aero group. We had to wait for [new aero chief] Mike Elliot to join us because we had a notice period he had to fulfil at Lotus," he is quoted as saying by Autosport.

"We concluded the situation with Loic and there was a gap that we didn't fill very well.

"On top of that we were doing the transition from 50 per cent to 60 per cent models in the windtunnel, and there were a lot of other things in the aero group as well. It did have an impact."

Merc are hoping the decision to switch to 60 per cent models will pay off next year as it allows them to get more technical data from Pirelli's tyres.

He added: "Our conclusion was that we would get a much more representative tyre at 60 per cent than at 50 per cent.

"Pirelli have to make 50 per cent and 60 per cent windtunnel tyres. There are only two teams that are still doing 50 per cent.

"Even with Pirelli's best efforts, they're going to be getting better feedback about 60 per cent tyres than 50 per cent. So we wanted to make the move.

"The other thing that has happened over the years is that you're putting more and more equipment inside the windtunnel model to measure, monitor and check. We just ran out of space in the 50 per cent model.

"There were things that we wanted to do that we couldn't do, and we needed the 60 per cent model to accommodate those features. Sixty per cent is the legal limit you can go to, there is no further step we can make."