British GP: Williams technical preview

Talking technical

Car dynamics

Average turn angle indicates the average angle of a circuit's corners expressed in degrees. The higher the average turn angle, the more acute the corners in the circuit's configuration and the greater propensity for understeer to compromise lap time. At Silverstone, the average turn angle is 1080 - 20 less than the average for the Championship. The circuit therefore has less effect on understeer than half the circuits on the calendar.

The end of straight (EOS) speed at Silverstone was 300kp/h in 2008. The British track ranks as having the 4th lowest EOS speed on the 2009 calendar, and this is one indicator of the wing level typically selected to optimise the downforce/drag ratio. Meanwhile, Silverstone has the 3rd highest average lap speed of any of the tracks on the calendar.

Pitlane & refuelling strategy

The pitlane length and profile (i.e. corners in the pitlane entry) contribute to the determination of the optimum fuel strategy. The pitlane loss at Silverstone is approximately 21.8 seconds, the 4th most penalising pitlane in the Championship. To complete a normalised distance of 5km around Silverstone requires 2.38kg of fuel against an average of 2.42kg per 5km across all circuits this season, making the circuit the 8th most demanding track of the year in terms of fuel consumption.

Safety car

Another key contributor to the determination of race strategy is the likelihood of safety car deployments, which are influenced by weather considerations, the availability of clear run-off areas that allow racing to continue while recovery takes place and the circuit profile, especially the character of the entry and exit into turn one at the start of the race. There have been 6 safety car deployments in the last 9 races at Silverstone, making it the 5th most likely race to produce a safety car period.

Temperature, pressure & humidity

As an example, it is a long observed tradition that drivers arriving at Interlagos complain about a lack of grip and an absence of engine power. Having become acquainted with a baseline of engine and aerodynamic performance during the season, the climb to 750 metres above sea level for one of the final races can, courtesy of the reduction in air density, rob a Formula One car of engine power, aerodynamic performance and cooling. The losses can come close to double digit percentages and thus have a very real impact on car performance. Air density is a factor of the prevailing ambient temperature, which varies most significantly by season, air pressure which is closely linked to altitude and, to a much smaller degree, by humidity. Thus if races are run at the same time each year, the factor that tends to have the greatest bearing on air density is elevation. Silverstone is 155m above sea level and has a relatively low pressure of 997.69mbar with a relatively low ambient temperature of 21o.C, so engine power will be average.

-credit: williams