By Mark Ward Technology Correspondent, BBC News website

Thousands of simulated tests prepare cars for race day

The car used on race day will have been exhaustively tested, every last inch of it.

So says Max Walshe, chief architect for BAR's PC systems, who heads the team making software that models the race cars in painstaking detail and then sends them careering round simulated tracks.

BAR Honda was in the news this week as it was given a two-race ban for breaking Formula One rules governing the weight of the car.

Test track

Mr Walshe said the hectic schedule of tests for the real cars means simulation is essential for working out designs for future vehicles.

One of the first parts of the process is exhaustively measuring the race cars and subjecting every component to a battery of tests to establish their mechanical characteristics and how they perform in different conditions.

At the end of every race all the data gathered about how the car and its components performed is fed back into the design and testing process.

This realism ensures that the cars being flung around the simulated circuits react just like the real ones.

"We test the cars without testing the cars," he said. "And because we can model the car mathematically we can model hypothetical cars."

At the end of the day we are looking for an edge..., Max Walshe, BAR Honda

Mr Walshe said the engineers can ask what would happen to lap times if a hypothetical aerodynamic shape was used?

The team create custom tracks that endlessly make a car perform the same manoeuvre, such as shimmying through a chicane, to ensure it handles well in every possible situation.

But care has to be taken to ensure that the computers driving the cars round the virtual tracks match human characteristics.

"Computers can drive cars much better than human drivers can and they can drive cars that humans would not have a chance with," said Mr Walshe.

In the UK, BAR employs more than 400 people to design, test and prepare cars for Formula One races. Testing and simulation has to be done quickly too because one season lasts only 19 weekends. It uses software from Compuware to make sure the programs run without problems.

Heavy testing

The cars being simulated typically differ slightly from the actual vehicles to help BAR home in on improvements that will make a difference on race day.

"It's all about identifying trends," he said.

One aspect of the car's construction that does get a lot of tweaking is weight distribution.

BAR Honda faces a two race ban for breaking weight restrictions

"The rules determine how it's going to look and are quite rigid" said Mr Walshe, "but there's still a lot of room for manoeuvre and you can certainly identify different weight distributions.

"The rules do not say you must have weight distributions of 50/50 front and back."

"That's a parameter we play around with quite a lot," he said. "The car has a lot of ballast in it that we can move around to achieve the front/rear spread of weight."

The result of the testing and simulation runs might be recommendations on where to use lighter components, or where to site ballast for the best result.

"It's a constant loop," said Mr Walshe. "We are feeding into that initially when we are designing the car and saying what's desirable and what's not. Then the designers go off and design these components and match these criteria."

This process can mean big changes in cars from year to year. Typically, said Mr Walshe, only 20% of the components in a car stay the same from one season to the next.