SCREEN TEST
One sign of the aeroscreen’s success is that not many people are now talking about it. But it’s going to make a difference to the challenge for the teams at the Indy 500
You only need to make a quick scan through social media and comment forums to realise that, as with the halo’s introduction in Formula 1, the number of vocal critics of Indycar’s mandatory aeroscreen is dwindling as onlookers 1) get used to it, and 2) acknowledge there’s no going back. There will, of course, be some who cannot reconcile themselves to its appearance, and it’s easy to sympathise. A device that is so harmonious from the side or front three-quarter view is not pleasing to behold from head on, and you can only hope that it can be better integrated into the next-gen Indycar’s design from birth, and look less like a late add-on to the otherwise handsome lines of the current Chris Beattie-penned car.
Those who remain vehemently opposed to the principle of the aeroscreens are a different matter. Too often they are folk who, somewhat ironically, sound and write like they are in the process of failing a concussion test. But even they will have to accept the aeroscreen is here to stay.
Indycar teams’ engineers recognised this change more than a year ago, and bent themselves to the puzzle of minimising the effect of the device’s extra 65lb (29kg) that moved the car’s centre of gravity forward 0.6% and up by 15mm. The issue wasn’t about adjusting the cars’ handling to suit the drivers, but preserving front-tyre life.
Ben Bretzman, Team Penske’s race engineer for 2019 Indianapolis 500 winner Simon Pagenaud, says that, while the difference sounds minimal, the effect was not overplayed. “It’s been a pretty significant change in how hard the tyres are working,” he says. “They’re doing a tremendous amount more work and, while it’s something you can see in the simulator, you don’t really know until you get on track – which has only been at race weekends because we’ve had no testing lately.
“Even going back as far as last August, when Will [Power] and Scott [Dixon] did the test at Indy with the aeroscreen, we could see how hard the tyres are taking it. In all our minds was immediately, 1) How do we get our balance back, and 2) How do you manage the tyres, particularly on a hot day? We won’t be able to run exactly like we did last year. Balance issues are going to be very noticeable.”
Bretzman expected long ago that qualifying at Indy was going to be more difficult, given the increase to 1.5-bar turbo boost (from 1.4 in previous years), and the fact that from lap one to lap four the tyres were going to go off a lot more rapidly.
The race, he says, will be an extension of this, even when back to the normal superspeedway race day boost of 1.3-bar.
“Yeah, it’s the same deal but over 30 laps or around that number the drivers are going to have to really manage their tyres so they don’t fall off a cliff in the last 10
laps of a stint,” he says. “And then there’s the dirty-air issue. In recent years at Indy, we’ve seen drivers happy to run in the wake of another car to save fuel and go a lap longer, but they may want to rethink that if it’s causing the car to slide around and accelerating tyre deg. Even the leader is going to have to think about it, too: where do you want to position the car in traffic?
“The car will need to be more versatile and the driver will have to use his tools a lot, because the difference in balance running in clean air compared with traffic will be bigger than usual. Dirty air will amplify the car’s understeer, which in turn increases the tyre deg, which in turn amplifies the understeer…
“And of course finding that ‘ideal’ set-up with more restricted practice time and therefore a busier track – that’s great fun… But at least the tyres have stayed the same. That means we expect greater tyre wear but at least the tyres are one of the constants, a baseline that we can build all the other decisions on.”
The fact the tyres haven’t changed in response to their extra burden will perhaps come as a surprise. Firestone’s first test in preparation for the aeroscreen’s introduction occurred last summer at Texas Motor Speedway, with Graham Rahal and Josef Newgarden running cars ‘ballasted up’ to car-plus-aeroscreen weight, and sure enough, coupled with the extreme heat that day, it seemed that at least the compound of the tyres would
need to be changed, if not the construction. But the test was far from conclusive.
“The thing is, that test couldn’t take into account the drag of the aeroscreen, which slows the cars significantly enough where they’re entering the turns at a reduced rate now,” says Firestone head of race-tyre engineering Cara Adams. “There’s less load on the tyres than we had estimated from the Texas test and our simulation work with Honda and Chevrolet, so we went into last August’s test at Indy [with Dixon and Power] a little bit conservative. We ran a couple of different tyres there but the car responded well to the 2019 tyre design.
“So we’re confident now that last year’s Indy tyre specifications will work well again. We built some of the tyres prior to the COVID shutdown [at the company’s
“I think our braking may have got a little bit better, despite the increase in weight”
Akron, Ohio plant] and the rest since we opened up.”
It’s not just blowing smoke to say that Firestone has become renowned for its priority on safety so, with the factory closed when the 2020 Indycar season eventually got under way in June at Texas Motor Speedway, the company was obliged to see what suitable tyres it had available already. The compound was a little softer than Firestone would have liked, given the new demands of the screen and the June heat in Dallas, so Indycar, under advice from its loyal tyre manufacturer, allowed each car to run just 35 laps per set.
Adams has no such worries about tyre performance at IMS. “Absolutely not,” she asserts. “After the test last August, this compound became the one we intended to run here, just like we ran the 2019 Iowa tyre at Iowa again this year.”
The aeroscreen has caused one noticeable change this year in the pitlane: there are now seven crew members allowed over the pitwall during a pitstop, with the extra person serving solely as aeroscreen attendant, pulling tear-offs. But the view out of the cockpit has ceased to be even a talking point for the drivers – “after a couple of laps I didn’t notice it was there” is the essence of their mantra. Cockpit cooling has been a more persistent issue, hence Indycar’s tireless quest for airflow options. Finding the right combination to create adequate through-flow has apparently been more difficult than finding two pandas that want to mate in captivity, but the drivers have been reasonably stoic, knowing it’s a process of trial and error, and most only mention it if asked.
Chip Ganassi Racing’s five-time champion and 2008 Indy 500 winner Scott Dixon has been far more intrigued by his car’s revised handling with the aeroscreen, and not just because of the tyre-wear issues outlined by Bretzman. “On road courses, it’s been as you’d expect where the car’s a little lazier on turn-in and you can feel it roll more,” he says. “But there are upsides too – I think our braking may have got a little bit better, despite the increase in weight, and maybe that’s because of the extra weight transfer under hard braking.
“The other thing I’ve noticed is that the car gets a little bit more loose in traffic compared with last year without the screen. I first felt it when we tested at the Speedway last year. It was only Will and ourselves, but when I was following him, I noticed that the typical front-end washout that you’d get from mid-corner to exit when you’re behind another car had been replaced by this sort of nervousness.
“Obviously that was a year ago, and since then we as a team may have made some changes that reduce that or even eliminate it, I dunno. It felt to me like it was just an underlying characteristic of the cars with this screen. I’m not totally sure why it’s like that, but maybe the aeroscreen is blocking some of the flow to the rear wing so there’s a bit less downforce back there and that’s helping to neutralise the car and get rid of that understeer in dirty air.
“But, we can sit here and talk about tyre management and how it’s changed because of the aeroscreen, and how the new weight distribution has shifted the car’s balance, and so on. And then we get to the race and something weird could happen, so actually it’s your fuel strategy and when the yellows fall that decide how the race plays out. That’s Indy: it’s never what you expect.”