PRUETT: Inside the development of IndyCar's Aeroscreen

Images by IndyCar

PRUETT: Inside the development of IndyCar's Aeroscreen

Insights & Analysis

PRUETT: Inside the development of IndyCar's Aeroscreen

By

Credit the relationship formed between Frye, the former head of Red Bull’s NASCAR team, and Red Bull F1 boss Christian Horner, for bringing the Aeroscreen to IndyCar.

“Well obviously Jay, and you know, we met during his time in NASCAR running the Red Bull entry, and obviously he has gone on subsequently to running a whole IndyCar program now,” Horner said.

“We just kept in touch with a few of the drivers and other bits and pieces and then he came to me with saying that they wanted to do an aeroscreen and obviously this was something that we developed in Formula 1 so it made a lot of sense to put the two groups together. I’m sure Formula 1 will keep a close eye on it as well, and see how it performs aesthetically as well as functionally and from a safety point of view.”

With one follow-up call to Red Bull sporting director Jonathan Wheatley, the project was approved. With Tino Belli, a renowned open-wheel chassis designer and IndyCar’s director of aerodynamic development inserted into the Aeroscreen development loop, the march toward 2020’s 2.0 version in concert with RBAT came into focus.

“I happened to be going to England for Christmas, and they asked me to go up and visit them; we had a very open conversation, and they were a very open book to us. They wanted to work with IndyCar on developing the screen,” he said. “Of course, Formula 1 went in a slightly different direction. They went in the direction of the Halo, and we went in the direction of the windscreen, let’s say, without the top frame. Just the windscreen on its own.

“The windscreen on its own didn’t quite work out the way we wanted. So the track test, it went well. It meant it was optically good. We knew there were going to be a few issues, which is head forces – which we found out in CFD and was backed up by Josef’s run here at the Speedway last year – and the other one is ventilation. But when we finally did the ballistic tests on the optical screen, it didn’t do well enough.”

FIA Halo, seen here on a W Series F3 car, was considered for IndyCar use but ultimately rejected.

With IndyCar’s aeroscreen prototype parked, its chassis supplier floated an alternative.

“One of the options was to, and this was Dallara’s suggestion, just to go to the regular FIA Halo,” Belli continued. “So we tested the Halo for visuals on the Dallara simulator, because there was concern that on the high banked speedways, the Halo would obscure the vision. So we ran with Scott Dixon and on the Dallara simulator with a standard FIA Halo, and to our surprise, it didn’t obscure any visions in any way. But when we came to do the stress test on the tub, this current tub couldn’t sustain the loads of the FIA Halo in the back corner of the cockpit opening, which made us revisit some of our other thoughts.”

Affixed to every custom F1 chassis atop the cockpit’s sidewalls, the Halo proved unsuitable for mounting in the same manner on the DW12, which was never designed to accept crushing vertical loads in those locations.

“So we then said, ‘Hey, you know, where are the strong points on the tub,’ and we said, ‘Well, the base of the roll hoop is strong,’ and later, we put in the strong point for the AFP on the front, and so we said, ‘Well, why don’t we make our windscreen with a top frame mount to those points?’ Belli said.

“So we partnered up with Red Bull to try and make a version of their screen fixed to the Dallara chassis. This screen incorporates a top frame so that it can take the big hits, like from a wheel assembly or a nose. Plus, we have the windscreen, which in our type of racing we need, because our racing is very proximal.

“We didn’t like the halo-only solution because debris could be deflected into the torso of the driver, and that would be catastrophic. That’s a completely unprotected part of the driver.” – Tino Belli

Marrying the Aeroscreen to the Halo met the safety objectives outlined by Frye’s team.

“You take Iowa, [a] 17-second lap, 24 cars,” Belli said. “Even if we have a parade, we’re basically half a second between cars. So when we have a crash with no runoff area on an oval, and a 175-mile-an-hour impact with a debris field that we can create, we knew that we needed a windshield as well, because, yes, big objects hitting the driver are not good, but small objects hitting the driver on the helmet is also likely to knock the driver out or give him a serious injury at 175 mph.

“We didn’t like the halo-only solution also because debris could be deflected into the torso of the driver, and that would be catastrophic. That’s a completely unprotected part of the driver.”

Aero effects of the new device should be minimal, Belli says.

Negative effects to the aerodynamic performance of the Chevy- and Honda-powered Dallara DW12s are negligible, according to Belli, with the Aeroscreen installed.

“On the main forces of the vehicle – and this will be surprising to a lot of your readers – the Aeroscreen really isn’t as detrimental to downforce and drag as you might expect,” he said. “It hurts a little bit more on the speedways, because the rear wing is so low. It’s basically below the level of the top of the windscreen. But when you get to the road course with the two-element rear wing, it really has almost no impact whatsoever on the car aerodynamics. You know, people are skeptical of this, but with the original PPG screen, we found the same thing and it was backed up on track, and the small changes that were needed to the aerodynamic setup of the car were what we found through CFD and in the wind tunnel was correct.”

More RACER