Circuit of the Americas: three corners in detail
Turn one
Turn one in Austin is one of the greatest first corners of the season. The run from pole is 500m but the track goes steeply uphill, with the turn-in point for the corner at the crest. Gear ratios will be spaced out here to give the driver strong acceleration up the hill without losing any speed at maximum velocity. At the top of the hill, just when the driver brakes for the hairpin, the load running through the car is suddenly released, which can cause massive instability if the engine is not completely in phase with the mechanical set-up of the car.
Turns 2 to 4
After the first corner the driver goes back up through the gears to reach seventh for turns 2, 3 and 4, which are taken flat out with an average speed of 280kph. Similar to Maggots and Becketts at Silverstone and the Esses at Suzuka, the driver needs to be precise on the throttle and carry the speed all the way through rather than brake and accelerate. The engine needs to be correspondingly smooth throughout the turns, delivering constant levels of torque. If the engine is too aggressive the car will be unstable and ‘bitey’ on turn in, which will only lose time and wear the tyres quicker.
Turns 11 to 12
Similar to Abu Dhabi and Korea, the longest straight is not the pit straight. In Austin it is the burst between turns 11 and 12. The straight here is 1,016m, meaning the RS27 will spend a touch over 13secs at wide open throttle with a top speed of around 315kph, which will be held for 2.5secs. Since this straight runs in a different direction to the pit straight, 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.
Rémi Taffin, Renault Sport F1 head of track operations
Safe to say that despite its novelty on the calendar, Austin has become a firm favourite with all of the team. The city is a fantastic place to visit and the track was equally impressive as the welcome we received. It’s a nice mix of technical corners and challenging external parameters, and with an average speed of close to 200kph, it is also a quick track.
The engine works in the mid to high range throughout the lap and there are some great corners, such as turn 1 and the final section, were the engine needs to deliver the right balance between response and smoothness. This is one of the tracks where we work especially closely with the chassis guys as there are a couple of blind turns where the driver will need to ‘feel’ the corner and have the confidence that the car will behave as he wants.
Equally the situation of the track, in the middle of the vast Texan grasslands, is a challenge. The lack of ambient humidity, on a par with Abu Dhabi and Bahrain, has two specific effects on the engine, one positive and one negative. The positive is that the air contains more pure oxygen so the engine is more powerful, however the very negative side is that the aridity stresses the engine. In fact, you can get an engine to ‘detonate’ if it is not managed correctly. This is a very destructive phenomenon basically consisting of an abnormal combustion of the air and the fuel in the engine, with subsequently massive stresses on the piston. To prevent this, ignition timing is tuned very carefully.
Temperatures were also quite cool last year, which made the fuel consumption fairly high over one lap. This is further increased by the changes in altitude and the stop-starts of the last sector. It’s not a particular concern, but it does mean that the starting fuel load will be one of the highest of the year.
Overall it is a race we are looking forward to. There are just two races to go for the RS27 before it is retired from service and we have hit a lot of records in the final phase of the year. We scored the 50th win for the RS27 engine and contributed to the final two titles available in the V8 era, taking the total to five wins in eight years. We are all motivated to keep these records coming and will be going all-out in the USA and Brazil to do this.