When asked how much time he spends designing, Bryan Holzinger, design engineer, Rahal Letterman Racing (Hillard, OH; www.rahal.com)—yes, it’s that Letterman; yes, that’s the team that Danica Patrick drives for—says, with certain exasperation, “It’s my full-time job. About 50 hours a week.” Now, this may strike some people who are familiar with the Indy Racing League (IRL; www.indyracingleague.com) as somewhat unusual inasmuch as (1) there are two chassis providers to the series, Panoz Motorsports and Dallara Automobili, and (2) there is one engine manufacturer, Honda (yes, a V8, a 3-liter engine that produces 650 hp), and the race teams don’t get to modify the engines.
So it is put to Holzinger: Don’t you purchase your chassis (think “car”) from Panoz—they’ve already designed and produced it, so what’s the design aspect? “Yes, we buy a race-ready stock chassis from Panoz,” he acknowledges. “But we’re allowed to make changes.” By his estimate, the number of changes that are made can be as many as 200 on a given vehicle. Which explains why he spends so much time working on a HP workstation (an x4000) working with a suite of tools within the ProEngineer Wildfire 2.0 package from Parametric Technology Corp. (PTC; Needham, MA; www.ptc.com). He’s designing a multitude of parts, for races on road courses, short ovals, and superspeedways, all of which, he explains, necessitate various “tweaks to make the cars go faster.”
According to Holzinger, testing is done by the team at each of those tracks. During testing, the cars are instrumented with more than 60 sensors that are used to monitor everything from gearbox oil temperatures to suspension loading. That data is combined with feedback from the drivers. Then it is a matter of the race engineers performing analysis. “They come up with ideas to make changes. Then it comes to me; I take the ideas and come up with the initial designs,” Holzinger says. It’s at this point where the various ProEngineer packages come into use, for design, structural and thermal analysis, all the way to programming for NC machining or sheet metal processing.
When they do this work, time is of the essence. Holzinger recalls that a couple of years ago, a race engineer was at a test session on a road course. He came up with an idea about modifying the steering arm on the car. So he sent the information to Holzinger. Holzinger went into the CAD model, made the modifications, then ran an finite element analysis (FEA) program to determine whether it could hold up. It checked out, so the information was sent to the machine shop where the G-code was generated for machining (Holzinger cites the fact that there is a fully associative capability in the CAD system as an advantage not only from the point of view of learning how to use it, but also in terms of assuring that all concerned are working on the same model). The part was produced and within a week the car was running with the modified steering arm.
Say a fastener breaks on the car. “It’s my job to figure out why it broke and to make a new one,” Holzinger notes. So whether it is a simple fastener or a major suspension component, they’re looking for an edge in weight, safety, and aero.
“Not all the teams in the IRL are as big as ours and they don’t have the ability to design and manufacture any component in house,” Holzinger remarks. Clearly, process technology is a competitive advantage.—GSV