In a period of hot events that started with Mexico and will continue into the European summertime, we look at what blazing sun, blue skies and humidity mean for the drivers and the co-drivers aboard the Subaru World Rally Team’s Impreza WRC2007s.
As the series approaches the inaugural Rally Jordan, crews prepare for potentially the hottest WRC encounter of the year as temperatures are set to soar to 40 degrees Celsius over the rally weekend.
Wind no cooling breeze, that’s near unbearable for the team members working in the service park, but inside the World Rally cars crews can face temperatures that are another 10 degrees higher.
Photo: SWRT
The sun’s rays are magnified through the window glass and the roof of the car, and the air inside becomes stifling. Of course, World Rally cars do not have air conditioning in the same sense as their road-going counterparts, and whilst they do have cockpit cooling fans, their efforts are often hampered by dust.
On dry and arid roads such as those in Jordan and Greece, the dust produced by the cars is substantial, and it would take a matter of seconds with the windows or the roof vent open for the car to fill with the swirling clouds.
Extreme in-car temperatures can rapidly drain the driver and co-driver of strength, focus and concentration, leading ultimately to a slower pace and a greater likelihood of mistakes.
Fitness plays a key role in the battle, as the fitter and stronger crews are, the less they will struggle with the physical demands of competition and therefore suffer from the loss of vital fluids through sweat. Fitter drivers are also afforded increased endurance in the heat, enabling them to attack the stages harder and for longer before tiring, and so both Petter and Chris have recently increased their training in preparation.
Hydration also plays a crucial role, absolutely essential to the sustained effort of the drivers and co-drivers over the course of the rally. Between them, either pair of Petter and Phil or Chris and Stéphane can consume 20 litres of specially formulated electrolyte fluid per day, helping to replace those essential vitamins and minerals that have been lost and boost strength and focus.
It is important that the crews do not just drink plain water however, as this can actually lead to a worsened condition and sickness. When drivers sweat, they lose minerals as well as water. If these are replaced simply by water, the body remains hydrated but severely weakened, in a condition called hyponatraemia.
The team also have two methods of reducing in-car temperatures as a result of absorbed sunlight, both of which focus on reflection. Firstly the side windows are lined with a protective and reflective film, similar to the concept of tinted windows on road cars, but in this instance silver in colour. Acting like mirrors, these simply reflect the majority of the sun’s rays and thus help keep the interior cooler.
Similarly, the Imprezas run with white patches on their roofs for the same end. White reflects heat more efficiently than the car’s normal blue, and seeing as the roof has a large surface area and absorbs a high proportion of the cockpit heat, it is a simple but effective measure.
Cockpit temperatures are just as important as extracting every last drop of performance from the car. Like engines, drivers and co-drivers don’t work well if they overheat.
