Allison: Hi, and welcome to the Product Design Show. IÆm Allison Toepperwein
Vince: And IÆm Vince Penman. Today weÆll see how design advances keep Indy race cars from literally taking flight.
Allison: YouÆve probably seen how a small mishap on the racetrack can trigger a serious crash, like the one IndyCar driver Dario Franchitti was involved in in August of 2007.
Allison: Franchitti credited the impact-absorbing body of the car in helping him walk away from the crash. His only injury?...a bruise on his nose.
Vince: The guy has his car flip at over 200 mph and he looks like heÆs in better shape than when I stub my toe on the bedpost.
Allison: Dallara, the Italian designer and manufacturer of that car, still spends countless hours designing and testing the roll hoop and the cockpit to continually improve driver protection.
Vince: However, Dallara engineers werenÆt satisfied with preventing injuries in a crash. They wanted to prevent the crashes themselves. They found that the events that lead to a crash like FranchittiÆs can be changed with some changes to the design of their car.
Allison: We spoke with Luca Pignacca, the Chief Designer at Dallara. Dallara has a storied 15 year IndyCar legacy and recently was named the exclusive supplier of the IndyCar chassis including the monocoque, suspension, wings, cooling system , fuel system , and brakes. ThatÆs basically the complete car other than the powertrain and the electronics.
Vince: Luca told us that because the cars are an open-wheel design, a potential source of a crash is the wheel of one car coming into contact with another car racing right beside it, a situation known as wheel interlock. So Dallara designed a new body, increasing the width of the cars by 25 mm to increase the chances that the bodies of the cars come in contact as opposed to one of the wheels.
Allison: Another consideration is the tendency for the car to lift off and flip, or react as a moment, when the car yaws, in other words, it starts turning sideways. It usually results from contact with another car-- just like what happened with Franchitti.
Vince: Design changes were made to the overall bodywork in a 3D model. The changes touched on the monocoque, the sidepods, the engine cover, the underfloor, and the wing endplates. The 3D model was then imported into a computational fluid dynamics program to simulate air flow at race speeds.
Allison: Dallara designers found that their design changes reduced the static pressures on the bottom of the car on the windward side, while increasing those on the top side. In this way, Dallara engineers found that they could reduce the moment around the carÆs center of gravity, and eliminate the chances that the car would lift off.
Vince: You can see Creo Parametric in action, the same software Dalllara used to design their 2012 IndyCar, by going to Ptc.com/go/creoparametric.
Vince: If you like the show, please give it a like on Facebook, subscribe on YouTube, or give us a rating on iTunes. WeÆll see you next week for more great design engineering.