(via Motorsport.com) – Learning a 20-turn track is challenging for racecar drivers, but spare a thought for those who have to make their cars fast through all those corners. Arrow Schmidt Peterson Motorsports race engineers Blair Perschbacher and Will Anderson explain to David Malsher how they prepared for this weekend’s race at Circuit of The Americas.
This weekend’s second round of the 2019 NTT IndyCar Series is the first time that the fastest open-wheel series in the continent will race at Circuit of The Americas [COTA], in Austin, TX., and you can be sure that, despite the two-day Spring Training test session in February, there are still nuances of the 3.427-mile, 20-turn course as yet undiscovered by IndyCar’s teams and drivers. And while the guy in the cockpit acquires knowledge with every lap, a race engineer is learning the track only through that same driver’s feedback and the data transmitted from the car.
By way of preparation for the COTA race, Arrow Schmidt Peterson Motorsports engineers have had an advantage over several of their counterparts in rival teams: they were able to use their not-very-secret weapon, rookie Marcus Ericsson, because he’s raced at the track five times as a Formula 1 driver. The Swede was able to provide insights for his Arrow SPM engineer Blair Perschbacher, teammate James Hinchcliffe and Hinch’s engineer Will Anderson. And, sure enough, despite vast differences between F1 and IndyCar, Perschbacher says his driver’s experience was very beneficial ahead of the February test.
He says: “Marcus’s track knowledge helped a lot, especially the first day, and we were right up there in the lap speeds. The second day we didn’t do quite so good setup changes as the first, but for sure his Formula 1 experience there helped him – it was one less thing he had to learn – and he helped the team as a whole.
“Of course the braking points change but the lines a driver takes are very similar between the two series, so on that first day Marcus was a long way ahead of some his rivals, especially in the Turns 2 through 9 section, which is all about rhythm and flow.
“That advantage became a lot less over the course of two days though. When you’re up against a Scott Dixon or a Will Power, they figure things out quickly because they’ve gotten so used to learning new tracks over the last dozen years. There may be some small things they’ve still got to nail down, but by the time we get to qualifying on Saturday, I expect they’ll be fully up to speed and Marcus’ advantage will be gone.”
However, Perschbacher says that his driver’s eagerness to learn and his methodology of building up to the point where he can switch into maximum attack mode are a carry-over from his F1 days.
“The way you approach a weekend and the way you study through a weekend and work on all the little pieces – out-laps, pitstops, getting up to speed in each sector, how soon can you lean on the tires – apply to both series,” he observes. “You just have to learn how it works in IndyCar compared to Formula 1. Our car has much less downforce so it moves around a lot more and I think Marcus is still getting the hang of that, but eventually it will be second nature.”
Perschbacher doesn’t hesitate when asked about the most difficult aspect of learning IndyCar for any rookie: that will be managing the red-sidewalled [soft-compound] Firestone tires on which drivers never get to test. They’re first sampled in second practice, then used in anger in qualifying and, by IndyCar regulation, for at least one stint on raceday. But Perschbacher is optimistic that Ericsson’s mental data acquisition will work in his favor.
“Marcus is similar to Robbie [Wickens] in that he’s thinking about things like that all the time,” he comments. “He was leaning on James and also Robbie [Wickens] in St. Petersburg [scene of the opening round]. The reds go off pretty quickly, so you only do a lap or two before they’re no longer at their peak. But Marcus is a good driver and he can figure out, ‘OK, I know what they’re going to do to the handling of the car and how much extra grip they’ll offer, so now I know what I need to do to get the best out of them.’
“The tires that Firestone bring to COTA will obviously be different to the street course tires, so for Marcus there will be another little learning curve, but again he can lean on James. And what Marcus learns at COTA will be usable at Barber [Motorsports Park, Round 3] and what he learned at St. Pete about the street course reds will be useful at Long Beach [Round 4].”
Traditionally, the day before a race weekend, engineers and drivers will walk the track – or in the case of a long track like Circuit of The Americas or Road America, will take a golf cart or mini-bike – studying and taking notes. All drivers, engineers and driver coaches carried out this duty at COTA on the day before Spring Training.
Their notes will include the intricacies of the curbing at each corner, the location and severity of bumps and pock marks, and identifying the areas where the asphalt has been worn smooth by repeated use and where the surface offers more grip but punishes a tire under lateral load.
“It can be very useful, especially on a track that’s new to us,” says Anderson, who is entering his second season with Hinchcliffe. “But it was super-valuable to have Marcus with us, being able to stop at each corner and have him point things out, such as late apex or early apex and which curbs you can use and which you can’t.
“COTA, like most of our road courses, feels extremely smooth when you’re walking on it or even riding it on a golf buggy. Then when you collect the data from the cars driving over it at high speed, you see the spots that have bumps and ripples. Input from Marcus and our driver coach Bob Perona who has also driven there meant that James had a pretty good idea of where the bumpy brake zones were before he went out and I was able to take what you might call our baseline road course setup and tweak it even before he went out on track for the first time.
“And those notes taken on a track walk can translate into ideas that spark when a driver comes into the pits complaining about how the car was behaving in a particular corner. I have the right information to prompt a driver to elaborate on what he feels the issue is.”
And so the next stage of a race engineer’s duties begins: turning what was a ‘tweaked’ version of a generic setup based on well-informed guesswork into the kind of optimal setup that might shave tenths of a second from the lap times in qualifying and/or help preserve the tires for a race stint. Now he has the ‘real life’ information he was craving, both from the data logged by the car on track and from his driver’s feedback. Anderson will want Hinchcliffe to describe the car’s behavior in fast-, medium- and slow-speed corners, on fresh tires and used tires, on short runs and long runs, on full fuel tanks and near empty tanks.
What’s particularly challenging about COTA is the wide variety of corner types. As mentioned, the first section of the track is a series of sweeping high-speed turns but there are also several low-speed corners in the second half of the lap. So, for example, an engineer won’t want to generate suspension compliancy necessary for handling bumps by raising the car’s ride-height. Since Dallara’s universal aerokit was introduced for 2018, the vast majority of an IndyCar’s downforce has come from its shaped underside, which creates areas of low pressure that cause the air underneath the car to accelerate and thus, to put it unscientifically, suck it down onto the track.
This allows higher cornering speeds… so naturally every millimeter added to the ride height or every extra degree of roll induced by high lateral loads will reduce that aero effect and harm cornering speeds. It may also damage the driver’s confidence, which blooms when he feels his car is planted. On the other hand, you don’t want the car’s suspension to be so stiff and its ride-height so low that it becomes unmanageable when tackling a track’s high-frequency undulations.
“Yeah, COTA’s a bit tough,” says Perschbacher, “because you have that high-speed section at the start of the lap with a lot of high-speed direction changes, and then you have much lower-speed corners like Turn 13 through 16. There has to be a bit of a trade-off. You try and get the car as low as possible so the underbody is creating as much downforce as possible, but you also want it high enough to deal with bumps or any corners where you need to go use the curbs.”
“COTA is very tricky from a setup point of view,” agrees Anderson. “There’s a ton of time to be found in the slow sections as well as the fast ones, so it’s very much a compromise track. So we use a lot of simulation to find out which areas of the track we should focus on to save us the most lap time for the quickest overall lap.
“This Indy car has a smaller operating window than the [2015-’17] manufacturer aerokit era, and by that I mean there’s a shorter distance between having a super-happy setup and a super-unhappy setup. There’s now a lot less downforce, so less grip. Those manufacturer aerokits gave you so much downforce and grip, they could mask a lot of handling difficulties.
“And compounding the issue of a smaller operating window is that the field is so good – strong teams, strong drivers – and they’ve all got the same chassis and aero pieces. It’s so tight that if you’re off by just a fraction, you’re going to look way off. So the details are that much more important to get right, because the consequences of getting them wrong are now highlighted.”
So too are driver errors, and that point will be emphasized during qualifying at COTA, says Anderson, due to the length of the track.
“On the red tires, the softer alternate compound, you’re probably only going to get one really good lap of ultimate tire grip. The peak grip, like at Road America [four-plus miles], is going to be around one-and-a-half laps, so if you don’t nail your qualifying run and get close to your best theoretical, you’re going to be in trouble and quite a long way down the charts. So I think you’re going to see the spread between fastest and slowest be a little bigger than we’re used to in this series.”
The race, however, will be another story.
“Yes, once everyone isn’t pushing to the absolute edge like they do for those single flying laps, the field is going to pack together,” he adds. “COTA is wide, the straights are long so there’s a lot of opportunity for drafting and there are also some long braking zones, so there are going to be plenty of opportunities to pass.”
The event organizers at Circuit of The Americas have branded their first IndyCar race the “IndyCar Classic.” Sounds like they could be more accurate than they anticipated – provided all those race engineers get their sums right.
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