Red Bull engineer Adrian Newey pledges future to team as Kimi Raikkonen tops the timesheets at winter testing in Jerez To now leave for another team would feel a little like walking out on your children in a way. On the subject of the RB8, Red Bull's challenger for 2012, Newey said he was not a fan of the FIA's ever more prescriptive regulations, adding that it was not easy to be creative with the 2012 cars. "When double diffusers were banned at the end of the 2010, we were able to largely replace the effect that they had with the exhausts [blown diffusers]," he said. This time around it's very difficult to replace the exhaust effect - we haven't managed to do it. Obviously, there is a re-optimisation to be done to the car. Whether we have done a better job on that than others is hard to know. There is no big grand idea that can replace that. It's about re-honing the car and understanding what is needed from the car with the exhaust gone. Newey said that the mysterious "letterbox" slot on the RB8"s stepped nose was "primarily" for driver cooling. "It's a shame to have to come up with a solution that is not particularly attractive," he said. But ultimately performance has to come before aesthetics and this is no exception. The slot in the nose is simply driver cooling. Traditionally the driver cooling slot is at the front of the nose, but really for styling as much as anything we moved it to where you now see it to break up the aesthetics of the ramp. Mark Webber ended the day fourth fastest for Red Bull after a frustrating morning in which the Australian lost the first three hours of running as a flight into Jerez containing the rear-wing assembly had to be diverted to Seville due to fog. Lotus" Kimi Raikkonen topped the timesheets on his return to the sport, with Force India's Paul di Resta second quickest, clocking up an impressive 101 laps in the process. McLaren's Jenson Button was eighth fastest of 12 cars. Button will be back in the MP4-27 on Wednesday with team mate Lewis Hamilton taking over for the final two days of the Jerez test. Times and laps in Jerez: Kimi Raikkonen (FIN/Lotus-Renault) 1min 19.670sec 75 laps Paul di Resta (GBR/Force India-Mercedes) 1:19.772 101 Nico Rosberg (GER/Mercedes) 1:20.219 56 Mark Webber (AUS/Red Bull-Renault) 1:20.496 54 Daniel Ricciardo (AUS/Toro Rosso-Ferrari) 1:20.694 57 Michael Schumacher (GER/Mercedes) 1:20.794 42 Kamui Kobayashi (JPN/Sauber-Ferrari) 1:21.353 106 Jenson Button (GBR/McLaren-Mercedes) 1:21.530 62 Felipe Massa (BRA/Ferrari) 1:22.815 69 Heikki Kovalainen (FIN/Caterham-Renault) 1:23.178 28 Pastor Maldonado (VEN/Williams-Renault) 1:23.371 25 Pedro de la Rosa (ESP/HRT-Cosworth) 1:23.676 44