Wednesday, April 29, 2009

What you may notice during F1 practice

When you watch Formula One drivers practice, keep a couple of things in mind.
First, being fastest isn’t everything. Although practice times are issued after each session, these times aren’t necessarily a definitive indicator of what shape every car is in. All teams work through their programmes in different ways and with different aims in mind. It’s often not until the qualifying sessions or the race that you see the true picture unfold as everyone tries to put together their best combination of factors. Treat the practice times as only a very loose indicator of competitiveness.
Second, some people get extra sessions. If you get to the track very early on Friday morning – well before the first official practice session – you’ll see some teams lapping the track while others never venture out and you may wonder why everyone isn’t out trying to beat the band. As a way of helping smaller teams cut costs, the FIA, the Formula One governing body, introduced a policy at the beginning of 2003 stating that a team could opt for one of the following:
  • To have unlimited test days.
  • To test up to a maximum of 20 car days (10 days for two cars or 20 days for one car) and be allowed to test for two hours on the Friday morning of each Grand Prix meeting.
The latter option is the cheaper one, but it has other advantages as well. It gives the teams a head-start in choosing the ideal tyre, in establishing fuel consumption figures, and in coming up with a good set-up. In terms of the work dedicated to the race weekend, by the time practice begins, they’re already one step ahead of those teams who can’t do the Friday test because they’ve opted for an unlimited number of test days outside of the Grand Prix weekends. The benefit of unlimited testing is that the total number of hours available for testing new developments and innovations is far greater. This particularly benefits the bigger teams who have more of such things to test than their smaller rivals.

Finding optimum fuelling in Formula One practices

The practice sessions are also used to verify fuel consumption and the precise relationship between fuel loads and lap times. These vary from track to track. A circuit with lots of accelerating in the lower gears and lots of hard braking makes for far less fuel efficiency than a track that flows more. But the engineers need to know precise figures so that no more fuel – and therefore weight – need be put in the cars than is absolutely necessary. The car tends to get quicker as its fuel load drops, but again, the engineers need to know by exactly how much in order to determine whether the extra performance brought by a low fuel load buys enough time to make an extra pit stop.
Often, the performance of the tyres degrades as the performance of the car improves because of its lower fuel load. At some crossover point, however, the car begins to lose more lap time from degrading tyres than it can find from lower weight. Practice gives the engineers and drivers a chance to establish where this point is. Again, this knowledge has a significant impact on the race strategy the team chooses.

Choosing tyres in Formula One Practices

The practice sessions also give the teams valuable information on the respective behaviour of the two different compounds of tyres that they have to choose from before Saturday qualifying. The sessions give them information on the differing wear rates of each tyre and also the difference in their performance pattern.
Practice sessions allow teams to see how the performance of each type of tyre changes over a number of laps. A softer compound is usually quicker initially, and invariably quicker from new on a qualifying lap. But it also tends to wear out more quickly than a harder tyre. Softer compound tyres also have a greater tendency to grain, a phenomenon where small tears appear on the edges of the shoulder, spreading across the whole width of the tyre, giving less grip until they stabilise. With less grip, the cars can’t go as fast as they would otherwise. Graining can last for up to 10 laps and, although the softer tyres may then be quicker than the hard tyres, after that the speed difference may not be enough to overcome the time lost because of the graining. Practice gives the engineers and drivers a feel for how this behaviour is panning out. Even though the data may tell a clear story on tyre choice, a driver may still be influenced by how each compound “feels”. A softer compound gives more grip and, therefore (in theory at least) offers a better lap time, but it also tends to feel less stable because its tread moves around more under cornering load. Occasionally a driver may find he is actually quicker on the harder compound despite its lower grip levels simply because it instils him with the confidence to push harder than when he’s using the soft compound. Practice gives the driver the chance to get used to the more squirmish behaviour of the softer tyre, or it enables him to quickly discard it and concentrate on setting the car up around the harder tyre.