Belgian 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. Average turn angle at Spa-Francorchamps is 760 which is the lowest in the Championship and highlights the flowing nature of the circuit.

The end of straight (EOS) speed at Spa was 319kp/h in 2008. The Belgium track ranks as having the 2nd highest EOS speed on the 2009 calendar, and this is one indicator of the wing level typically selected to optimise the downforce/drag ratio. Meanwhile, Spa has the 2nd highest average lap speed of any of the tracks on the calendar.

Pitlane & refuelling strategy

The pitlane length and profile contribute to the determination of the optimum fuel strategy. The pitlane loss at Spa is approximately 19.8 seconds, which is the 6th least penalising pitlane in the Championship. To complete a normalised distance of 5km around Spa requires 2.25kg of fuel against an average of 2.42kg per 5km across all circuits this season, ranking the circuit as the 2nd least demanding 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 4 safety car deployments in the last 7 races at Spa, which means that there is a 57% chance that the circuit's character will induce 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. Spa Francorchamps is 410m above sea level and has the 3rd lowest average pressure (968 mbar) of any race venue in the 2009 championship. As a consequence, the circuit's ambient characteristics will result in a significant reduction in engine power.

-credit: williams