Getting technical in Texas - Renault on Austin’s engine needs 14 Nov 2012
The FIA Formula One World Championship™ returns to the USA for the first time since 2007 this weekend, with the inaugural Grand Prix at the Circuit of The Americas. The 5.516-kilometre track is set in the Texan countryside outside Austin and features corner profiles similar to some of the most challenging complexes ever seen on the calendar, including the Suzuka Esses and Turn 8 from Istanbul Park.
There are also several gradient changes over a lap, particularly in sector one, which features a blind apex that will really push the drivers. Learning the track will be a challenge for the teams too, as well as their engine suppliers, as Renault - who power Red Bull, Lotus, Williams and Caterham - explain…
As a new event on the calendar, Renault will use all the tools at their disposal, including computer simulation and engine dyno running, to prepare for the Grand Prix. More than double the time is spent testing engine maps on the dyno than would otherwise be the case for a ‘normal race’; so approximately four days of dyno running and simulations.
Simulations predict an average speed over one lap of 196 km/h during the race and just over 205 km/h during qualifying. There are two long straights but the average speed is lowered by the high volume of low-gear corners; eight of the 20 turns are taken in third gear or lower. This puts the Circuit of The Americas in a similar bracket to Valencia.
Similar to Abu Dhabi, the longest straight is not the pit straight, but rather the burst between Turns 11 and 12. The straight here is 1,016 metres, meaning Renault’s RS27 engine will spend a touch over 13 seconds at wide open throttle. Top speed is predicted to be 314 km/h at the end of this straight and the engine will spend 2.5 seconds at maximum revs before braking for the hairpin of Turn 12.
The second long straight is the pit straight. Both straights run in different directions so correctly selecting seventh gear will depend on wind direction on the day. Selection for the one may compromise end-of-straight speed for the other, so ambient conditions will be carefully monitored throughout Friday practice to find the optimum ratio.
The track is similar in power sensitivity to Malaysia, with 57 percent of the lap taken at full throttle during the race, and just under 60 percent during qualifying. The predicted lap time is around 1m 39s.
Three hairpins triangulate the track; Turns 1, 11 and 12. Revs will drop to 9,500 rpm and the car speed to just 80 km/h. All three come after a long period of open throttle, meaning engine braking and rear stability on the apex are crucial. The exits and correct engine response from the hairpins are however equally important since they each lead back onto another straight.
Fuel consumption is one of the highest of a season over one lap, similar to Abu Dhabi. The lower temperatures of Austin offset its relatively high altitude and change of gradient, but low ambient humidity and the twisty first and last sectors where the driver is constantly on and off the throttle increase consumption. The starting fuel load will be one of the heaviest of the year, on a par with Abu Dhabi and Melbourne.
“Going to a new track always presents a new set of challenges as we rely heavily on simulations conducted in the dyno and on various computer modelling software,” says Remi Taffin, Renault Sport F1’s head of track operations. “The accuracy of the models is such that we can gauge starting gear ratios, fuel consumption over one lap and a basic torque map, but nuances such as the kerbing, the abrasiveness and the undulations of the track will all need to be assessed on site.
“The first sector starts with a low-speed hairpin that will require good engine braking and response on the exit since it opens out to a flowing sequence of turns that have characteristics of the Maggotts-Becketts complex in Silverstone or the Esses in Suzuka. This turn is also blind, so the driver will need to ‘feel’ the corner and have the confidence that the car will behave as he wants. The next sector will be a fantastic challenge for drivers, and also for engine engineers as this type of complex is the hardest to map! The average speed through this sector will be around 210 km/h in fifth or sixth gear with the revs no lower than 15,000 rpm. The internals of the engine will also be subject to high lateral g-forces as the driver rapidly switches direction.
“A high percentage of sector two is given to the long straight, one of the longer straights on the calendar at just over a kilometre. Despite its length it’s one of the easier parts of this track; it’s sector three that is going to present the hardest challenge as it includes corners similar to the most challenging corners on the calendar; the stadium in Hockenheim and Turn 8 in Istanbul! This will be one of the sectors we will work the hardest on when we arrive.
“What you can’t see from the track map is that there is a lot of undulation change over the lap, very similar to India. This will put an extra strain on the engine internals as the lubricants rise and fall within the systems over the crests and dips, but we do not expect it to be a particular concern as we already have plenty of experience on this type of track from Spa and India this year.”
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