The Williams team had a mixed day on Thursday at Jerez, with Nico Hulkenberg losing a lot of valuable track time due to a hydraulic leak.
AUTOSPORT talked to technical director Sam Michael about the Grove team's progress so far.
Q. How was your programme on the first two days?
Sam Michael: It was very wet yesterday (Wednesday) but we did loads of miles. We got some dry running in on Thursday but we had a few reliability problems in the morning. We had a hydraulic problem, which was a bit annoying in the dry, but that's what happens with a new car.
Q. Is it a one-off problem or something that you have to make modifications to fix?
SM: We saw straight away what the problem was, it just took a long time to fix because it showered the clutch with oil and things like that so we had to change the clutch and some other bits and pieces as well. We've got much bigger problems to solve than things like hydraulic leaks!
Q. Have there been some changes to the car since the Valencia test?
SM: There are some changes from a reliability point of view but nothing from a performance point of view. The car will stay the same until the Barcelona test.
Q. At Valencia you were working on getting the car talking to the Cosworth. Are they chatting pretty well now?
SM: Yes. It's ongoing, but pretty good compared to how much running we've done.
Q. You have got the most experienced F1 driver in Rubens Barrichello and a rookie in Nico Hulkenberg - how is the feedback?
SM: It's good. They are obviously at different stages of their career but their feedback seems to match each other.
Q. Given that so much this car is new, is it particularly difficult getting through all of the work you need to do in such a condensed period of time?
SM: It is compressed, but looking at the laps that everyone else is doing it doesn't appear that we are missing out that much, especially if you look at the mileage that we did on Wednesday as you are still putting wear on the parts. A lot of other teams have been having problems that are stopping and starting them, so we aren't missing out a lot. The main thing at the moment is to spend time on set-up. We did spend some time on setup yesterday but not as much as we'd hoped because we lost about three hours in the morning.
Q. Are you happy with the brake performance with the heavy fuel load?
SM: Yes, the wear has been OK. We brought a couple of little modifications here to improve the brake cooling.
Q. Looking at Fernando Alonso's long run yesterday, does that add weight to the belief that Ferrari currently has the edge?
SM: We'd have to go out and do the equivalent run to know that and we were planning to do that yesterday afternoon but we didn't get off our morning setup programme. It was a good run, but it didn't look scary in terms of us being miles away from that. In Valencia our long runs compared to them were not too bad, because when they do runs like that you can see what they are doing with fuel.
Q. You have the medium and hard compound slick tyres here - did you have any problem with warm-up?
SM: Not particularly. A little bit on the hard, but that was the first run in the morning when the track was pretty green.