Cars will be differentiated by their shape as the manufacturers have designed aero kits for speedways and road and street course/short ovals for the Dallara IR-12 chassis.
Manufacturer track testing of prototype components opened Oct. 6 and continues through Jan. 18, which is the same date as homologation. Production will ramp up to meet the March 1 deadline for one road and street course/short oval kit to be delivered to each entrant. The speedway aero kit, according to the INDYCAR timeline, will be delivered by April 1.
The initial team on-track test is scheduled for March 16-17 at Barber Motorsports Park in Birmingham, Ala. The 99th Running of the Indianapolis 500 Mile Race on May 24 will mark the debut of the speedway aero kit.
In the Q&A below, INDYCAR director of aerodynamic development Tino Belli provides insight into the regulations of the aero kit legality boxes and options available to teams for the 2015 season:
Q. You're one of the few who has seen both manufacturers' aero kits on the track. Will fans notice differences from last season?
Differences between the 2014 Dallara chassis and the 2015 aero kits and between the Chevy and Honda aero kits will be quite easily spotted by an interested fan. Especially to someone who is interested in technology, they'll see many differences between the cars. At speed and with different color schemes, it might be more difficult to see the differences.
It's certainly not going to be a spec car, and it's not spec even within the Chevrolet or Honda environments.
The Chevy might not always run in exactly the same configuration between a Penske and Ganassi car, and the same with Honda between, say, an Andretti and Schmidt Peterson Motorsports car because teams will have options.
Q. To review, what were the legality boxes — areas open for development by manufacturers — for 2015?
The engine cover, sidepods and rear wheel guards are common between the speedway and road/street course/short oval packages. On the speedways, the manufacturers can do a new front wing main plane, rear wing end plates, front wing end plates. Teams are allowed to use optional components that fit to the sidepods, engine cover and rear wheel guards such as winglets and flicks.
The teams will have quite a lot of things they can play with if they decide that they can come up with a better solution for their particular requirements and their driver or car set-up. The car set-up is not only going to be a downforce level like a wing angle, springs, shocks, toe and camber. If a particular type of mechanical set-up needs an aerodynamic solution, they can try what they like.
We believe there will be a reasonable number of components that the manufacturers will homologate as optional that a team could investigate to see what could give it a better solution on a particular racetrack. An example is the Indy road course, which because of the length of the straights is a low-drag racetrack. You can imagine teams coming up with a hybrid speedway/road course solution. They can't put on a speedway front wing on a road course, but they could perhaps use speedway sidepod options.
Another thing we're allowing is all of these optional components can now be changed between qualifying and the race. A team could decide to go for a super low drag qualifying set-up and use the newness of the tires to try to get the speed and then revert to a more high-downforce race set-up, which could mean a change in some of the components on the sidepods, wheel guards and engine cover. For a long time, we had what you qualified with is what you raced.
The same will be true for the Indy 500 with the optional components. In qualifying for Indy you might put on all your lowest drag optional components or choose to emit components, and then for the race you might decide there is some sidepod winglet that might give you better handling characteristics or is more efficient.
On the road course in addition to the sidepods, engine cover and rear wheel guards is the front wing flaps and end plates, and the rear wing end plates. The rear wing is a standard Dallara main plane for all events except for the Indy 500, during which teams can choose between the Dallara or their manufacturer's main plane. The engine air intake will be different from the Dallara chassis, too.
Q. What happens with homologation?
On Jan. 18, everything is frozen. So we require the CAD files, the weights of the components, the layer books. We don't have to have a component in our hands by Jan. 18, but we have to have all of the designs in our hands and they will be locked down at that point.
The only thing the manufacturers can do afterward is if they have some sort of reliability issue or if they could prove they could save significant money by altering a construction technique to save money they can ask for a concession. The component won't be allowed to be any lighter and we want it to have similar stiffness.
Q. How often can any of the legality boxes be upgraded?
From a performance point of view, except for the sidepod and engine cover that have to remain fixed for two years, all of the other components are up for being upgraded. But they only are allowed to upgrade three legality boxes total in a two-year period.
Currently, they can choose to homologate a new component in one of the three boxes any time from the beginning of the 2015 season to the end of the 2016 season. If one manufacturer feels it is behind in a particular configuration, it can bring forward a box to try to catch up earlier. If you're feeling confident or comfortable, you'll want to delay upgrades until after you see how 2015 pans out with all the different racetrack configurations we go to.
The components that get changed, the old components are grandfathered so teams can still choose to continue to use those components or use them as spares.
Q. How will the process of policing the aero kits work?
Our task is to make sure that the component as homologated doesn't get altered by either the manufacturer or team. We want the bodywork run as the aero kit manufacturer designed it and manufactured it. We'll be checking the weight of components along with the shape and stiffness of the components. Like the current technical inspection, there will be a combination of jigs and fixtures, load tests, maximum and minimum height dimensions and then we'll continue with the laser scanning that we tested last season so we can compare our record of the CAD of components against the car any time.