THE SECRETS OF F1 TESTING
What actually goes on when a Formula One team conducts an official test session? We go behind the scenes with Renault’s chassis boss to find out
EVEN a casual Formula One fan will be familiar with the routine of a race weekend: free practice on Friday, qualifying on Saturday and the race on Sunday. But what goes on between events? How do the teams design and develop the machines that Hamilton, Rosberg and co do battle in over 21 weekends a year – especially now that testing has been severely curtailed by governing body the FIA in order to keep costs under control.
At one of those few permitted test sessions – taking place at Silverstone the week after July’s British Grand Prix – we sat down with Nick Chester, chassis technical director for the works Renault Sport F1 team, to get an insight into how the design of an F1 car makes it from the engineer’s mind to the race track.
Designing a race-winning F1 car hasn’t got any easier in the last two decades, but when Chester first joined the sport back in 1994, working for the small Simtek team, pretty much the only limit on how much you could test was your budget.
Fierce
“We used to do maybe 15 tests a year on top of the races; it was a fierce schedule,” he recalled. “We needed to run a separate test team and chassis, which ballooned into a lot of expense. As an engineer, you always want more testing, but the limitations were brought in for cost reasons, which was sensible, as the cost was pretty big.”
Testing was initially restricted to 30,000 miles a year, before being brought further under control in a series of official pre and in-season tests. This greatly reduced on-track running has forced teams to rely ever more on simulation tools.
Mechanical options include four-post rigs that simulate loads on the suspension, engine dynos where F1’s powerful and complex hybrid drivetrains can be put through their paces without moving an inch and the wind tunnel, where scale models of the cars are subjected to high-speed airflow.
Aside from the wind tunnel, another tool used to simulate airflow is Computational Fluid Dynamics, or CFD. The processing power required to simulate the air moving over a racing car is immense: Renault’s supercomputer can carry out 45 trillion calculations per second, has about 5,000 times more memory than your average laptop and generates 150GB of data an hour.
Then there’s the ‘driver-in-the-loop’ simulator – a more recent development generally referred to as ‘the simulator’. It’s like an extremely sophisticated version of the ‘wheel and pedals’ set-up used by serious racing gamers, but with hydraulics used to replicate the forces experienced when driving the real thing.
The various simulation elements are used together as much as possible – aero models generated in the wind tunnel will be loaded into the driving simulator, for example – and all are constantly being developed to make them as close as possible to representing real life. Also, CFD processing power and time spent in the wind tunnel are both limited by the FIA, so the teams have a decision to make as to how much of one or the other they use to achieve their development goals.
Yet despite all this complexity, Chester maintains that while simulators are useful tools, there’s still no substitute for real-life testing. “The driver sim doesn’t feel quite like a real car; it doesn’t have quite the
“Renault supercomputer can do 45 trillion calculations per second, and has 5,000 times the memory of most laptops”
same cues for the driver, so it’s still important to test on track,” he explained.
It’s up to him and other Renault engineers to put together a programme that makes the best use of the very limited on-track time. “A whole raft of things go into it: aerodynamic developments, mechanical changes, tyre experiments,” he explained.
“A few weeks before, we’ll start putting all that together and working out our priorities and running order. Our primary concern is always performance, so that tends to decide things, but there’ll also be parts that might be lighter or help with reliability.
“There’s usually twice as much stuff to do as you’ve got time for, so it’s a case of working out which bits are most important and what you really want an answer on. The approach is similar to when we tested a lot more, but there’s more packed in. You can see that with the mileages teams now do in testing: a lot will do 120 laps a day, whereas when it was free, they used to do maybe 80.
“There’s a lot more pressure to pack a lot into a test day now: 10 years ago you had the luxury of being able to ‘back-toback’ things many times to make sure you had a really clear result. Now, you have to try to get that result a bit quicker.”
And with 2017 set to bring a radically revised set of technical regulations, making the most of limited testing has never been more important. As Mercedes has shown since the introduction of hybrid engines, if you get a head start on your rivals, it can be nigh-on impossible for them to catch up.
Sport “The driver simulator doesn’t feel quite like a real car; it doesn’t have quite the same cues for the driver, so it’s still important to carry out testing on a track” Nick Chester Chassis technical director, Renault Sport F1