Some significant rule changes have made this a busy winter for all the F1 teams, although this year continuity in terms of engine and gearbox supply has been a boost for Force India. The team's design director Mark Smith explains some of the thinking behind the VJM03.

Last winter Force India had to deal with a relatively late change of engine supplier and the switch to a McLaren gearbox. How much smoother have things been this time around?
It's been a lot smoother. From the very beginning we designed the VJM03 in full knowledge of the engine and gearbox that we would be using for 2010, which gave us a significant advantage by comparison with respect to the same point in design time for VJM02. Fundamentally, key relationships are established and data is available to us much earlier. The result of this is a much smoother design and development process.

In 2010 there is no refuelling, the front tyres are narrower, and wheel covers are banned. Have those changes dominated your thoughts, or were there any other key issues?
In terms of the way the car was designed and their impact upon performance, it's predominantly those three factors. The wheel covers were an aerodynamic device, so you take them off and develop around the new configuration. The refuelling ban however has had a significant impact upon a number of areas, such as the wheelbase, cooling system layout and the way the fuel system has to perform without fresh fuel going in every 20 laps or so. The narrower front tyres have a little bit of an aero implication, but primarily it's a case of best predicting their on track performance because their characteristics appear on paper to be quite different to last year's.

What sort of differences should we look for on the VJM03 compared to last year's car?
It's a natural progression in areas which seemed to have strong trends at the end of 2009, and in other areas it's quite different. The back of the car is the area that has evolved most as everyone has had a year of experience with the double diffusers so we've all gone into 2010 much wiser to what we can do. There have been some refinements in that area and it's formed part of the make-up of the car this time around, rather than being added very quickly, as happened at the beginning of last year. It's natural now to design the car to take these devices. The gearbox is now a little bit easier to work around, and there are tweaks to make the diffuser potential bigger. So there are some notable differences.

What are the implications of the narrower front tyres?
The main implications are the way in which the new tyres will influence the balance requirements of the car in aerodynamic, mechanical and weight distribution terms. Whilst we have up front data for the tyres, it will only be after running the car on circuit that we will have the real understanding of how they interact with the car. Also, the range of fuel load carried on board the car in 2010 is significantly higher than it was in 2009 and this is expected to place further demands on tyre management throughout the race. All of this will mean that there will be a premium placed upon looking after the tyres and some driver / car combinations are likely to derive an advantage from this.

How much effort went into calculating the optimum fuel tank size? Potentially if someone gets it wrong, they could be in trouble in high consumption races such as Montreal and Valencia.
A lot of effort went into this. Since the fuel cell size impacts upon many areas of design it was important to target the maximum requirement as accurately as we believed possible. Firstly, we undertook a thorough analysis of historical data and then modified that with the effect of factors such as increased fuel load and revised aero effects upon laptime and consequent fuel consumption. There was also good input from Mercedes in terms of their predictions for consumption.

The extra fuel has to go somewhere. To what extent has the chassis grown to accommodate it?
Maximum width of the fuel cell is limited by regulation so the main effect is for the chassis to have grown in length.

What are the implications of the heavy fuel load?
The implications on lap time are obviously very big - you are probably talking about up to five seconds. So the cars will certainly go a lot slower at the start of the race. It will be a lot more difficult for the drivers with a heavy load, and certainly our drivers weren't around in the last era with no refuelling! Then you've got your brakes to manage as well. We have our methods of looking at how the brake cooling works, and the targets have been re-set for the fuel loads and energy predictions that we've had.

Last year you quickly abandoned the option for an adjustable front flap because incorporating it made it harder to keep up wing development. Will it be more important to have the system operational this year?
I think it's potentially more important. No one really spoke about it much in the paddock last year, we didn't get the impression it was a big boost for the drivers, so we were happy to do without it. But given that you've got the scenario where you've got to manage the car in a race now, it's a good thing to have if you can. So we're making efforts to 'future proof' it this year.