Bahrain 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 Bahrain, the average turn angle is 123.560, against a season average of 1100, ranking it as the circuit with the 5th highest average turn angle across the Championship.

The end of straight (EOS) speed at Bahrain was 303kp/h in 2008. Bahrain ranks as having the 8th fastest EOS speed on the 2009 calendar, and this is one indicator of the wing level typically selected to optimise the downforce/drag ratio. As the average speed around Bahrain is the 8th fastest of any of the tracks, a compromise is required.

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 Bahrain is approximately 23 seconds, the 5th most penalising pitlane in the Championship. To complete a normalised distance of 5km around the Bahrain circuit requires 2.66kg of fuel against an average of 2.42kg per 5km across all circuits this season, making the circuit the 4th least 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. Since the race debuted on the calendar in 2004, there has been 1 safety car deployment in Bahrain, in 2007, making it statistically unlikely that the circuit's character will induce safety car periods. The first two races of this season have already seen 5 safety car periods, however, so anything is possible!

Temperature, pressure & humidity
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. Like half the races on the calendar, Bahrain is close to sea level, just 10m above, and has an average pressure (1,011 mbar), so engine power will be good.

-credit: williams