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Rahal

Owner-Driver Bobby Rahal

Racing with Technology

Here's a look at how CAD/CAM/CAE systems and CNC machine tools are being used by Team Rahal to develop vehicles that may be just a little bit faster than those that the other guys have on the track.

Although the world of racing in the Championship Auto Racing Teams (CART) series—which puts Indy car-type open wheeled vehicles on courses in North America, South America, and Australia during 17 events—may seem somewhat distant from the day-to-day world of designing and building automobiles for the streets of those continents and others, there are a lot of similarities. As Brian Dean Willis, an engineer with Team Rahal (Hilliard, OH), puts it, "Our primary focus is to race, compete and win with our car. That's the whole focus and purpose of our company." And which company that builds cars—be they a Monte Carlo or a Masserati—doesn't want to get in the thick of the competitive market place and win the sale due to having a superior product?

Willis admits, "We're different from other Indy car race teams. This organization is run along the lines of a design and manufacturing facility."

Team Rahal, which is owned by champion driver Bobby Rahal and, as a minority partner, Late Show host David Letterman, campaigns two drivers: Rahal and Bryan Herta. The team employs Ford-Cosworth XD engines (hailing from Cosworth Racing, of both Northampton, England, and Torrance, CA). The chassis is built by Reynard Racing Cars in its Bicester, England, factory.

The nature of the racing series is such that the engines—which are also produced for the various teams by Honda, Toyota, and Mercedes (see, there are some similarities to the more quotidian aspects of motoring)—are sealed. That is, unlike, say, the NASCAR series, wherein the teams can modify and machine engine components for a competitive edge, the CART teams lease engines for particular races. Some engines are setup by the builders for super-speedways like the U.S. 500 race at Michigan International Speedway; some engines are setup for tracks like the Grand Prix of Monterey at Laguna Seca. When the race is over, the engines go back to the engine builder for rehabbing.

Where the teams can make a mechanical difference is in various components of the vehicle's structure, as long as those modifications fit within the specifications of the sanctioning body (e.g., length, width, height, wheel base). Several teams, in addition to Team Rahal, have Reynards. Others have chassis made by Lola Cars. Roger Penske has a shop in Poole, England, that produces chassis for his team. Dan Gurney and Carroll Shelby founded All American Racers back in 1964; last year, after a 10 year hiatus, AAR Indy cars reemerged on the scene. And there's a new builder, Swift Engineering, that's based, like AAR, in California.

 

Fractions Count

Team Rahal buys cars from Reynard for approximately $450,000 each. That doesn't include the engine. Nor the tires (but there is a set of wheels). What a team gets from a chassis builder is what is called a "rolling chassis," which consists of the body, suspension and steering system. There isn't even a dashboard thrown in. As mentioned, other teams pull out their checkbooks and can buy the same cars, and they may also run the Ford engine and put on Goodyear tires. "The problem we have, of course, is that if you're going to race against someone else in the same package, if you use just what the factory supplies you, there's no way your car is going to be any bit better than what anyone else has," Willis says. To be sure, there is an edge that comes from the drivers. But there is a fairly consistent group at the top of the rankings, race in, race out. Willis notes that during qualifying, positions on the starting grid can be based on differences measured in thousandths of a second.

For example, during qualifying for the first race in the PPG CART World Series, which was held at the 1.5-mile oval track in Homestead, FL, the pole went to Alex Zanardi (who runs a Reynard chassis, Honda engine, and Firestone tires) for his speed of 195.043 mph. Second place went to Mauricio Gugelmin (Reynard/Mercedes/Firestone), who was just 0.025 seconds slower, at a speed of 194.869 mph. It isn't until the 20th qualifying position, achieved by Andre Ribero (Lola/Honda/Firestone), before there is a difference of more than one second behind the pole (Ribero qualified at 186.695 mph).

 

A Little Quicker

"You have to do everything you can to try to make your car a little better because that's all it takes to be a little bit quicker," observes Willis. "You have to find some sort of competitive edge. For this company, Bobby has decided the way to get the edge is to invest heavily in the engineering and manufacturing side of things. Our philosophy around here is that the only way you can be competitive is to design new parts, test out those parts, and put them on the car rapidly and efficiently. The more parts we can put on and test, the more chances we have of finding a new part, a new design that works better."

So in the Hilliard facility, the engineers and the machinists are working with state-of-the-technology systems and equipment that permit them to try to find that edge, that little something that, ideally, will pay off in podium finishes.

What these people do is really go at all aspects of what arrives from Reynard, trying to find the optimum for individual pieces, right down to the smallest brackets. Reynard engineers, of course, try to put together the best package they can within the time and cost constraints that they have. Willis calls the vehicles they buy from Reynard "a starting point." Analogous to this is someone who buys a car from a dealer then sets about to customizing it. The difference, of course, is that whereas the home mechanic may have the greatest set of Craftsman tools you've ever seen (Craftsman is, incidentally, a Team Rahal sponsor), the Team Rahal shop is running seven seats of Pro/ENGINEERING CAD/CAM/CAE software (including Pro/MECHANICA for functional simulation and Pro/MANUFACTURING for developing part programs) from Parametric Technology (Waltham, MA) on Hewlett-Packard (Cupertino, CA) workstations (four UNIX boxes and three NT). Down on the shop floor there are four machine tools from Mazak Corp. (Florence, KY): two vertical machining centers, a CNC dual-spindle turning center, and a four-axis turn/mill center.

They are serious about their modifications.

 

Making Changes

So what do they do with all of this capability? Willis answers, "We change the front and rear suspension all the time. Try to make it work for any particular track." That is, the cars run on four distinctly different types of tracks. There are: fixed road courses, where the speeds range from 50 to 200 mph, up hills and around curves. There are street circuits, where the speed may be from 35 to 165 mph, over the bumpy, greasy roads that are what the rest of us drive on in our daily commutes. There are short ovals—one to 1-1/2 miles around—where it is all left hand turns, speeds from 160 to 195 mph, and lots of traffic—the front of the pack tends to catch up to the rear within 10 laps. Finally, there are the super speedways, where the speeds average in excess of 200 miles per hour. Obviously, no single suspension is going to be able to handle all of these variables.

In addition to the suspension, there are the front and rear wings that provide aerodynamic properties. These, too, must be modified, depending on the course. In addition, Willis says, they change the complete water and oil plumbing system, and the internals in the gear box (not gears though). The chassis proper, which is a carbon fiber tube that runs from the front of the car to where the engine is located, is one thing that isn't changed, as it really is the foundation. If possible, the side pods (which hold the radiators) and the undertray, which is the bottom of the vehicle, aren't changed, Willis says, because of their size, complexity, and cost. "That doesn't mean we won't change them," he stresses, and points out that they have redesigned the undertray—a $60,000 part. "We'll change anything that we think will benefit us." He proudly points to a redesigned lug for holding the wheels on the car.

Not only does Team Rahal have the aforementioned CAD/CAM/CAE systems and machine tools, it also has a complete composite-parts manufacturing capability which permits the creation of the parts. Should they need a large autoclave to cure parts, then they turn to Textron Automotive, one of their sponsors, for it.

 

Math-Based Design

The objective of "math-based design" is to create a model in CAD that will run through the entire development, engineering and manufacturing cycle. This is precisely what is happening at Team Rahal.

The engineers at the firm were not unfamiliar with using CAD/CAM systems. The machinists there became quite adept at using the conversational programming capabilities on the Mazak machines. But Willis explains that approximately two years ago, a determination was made that the existing CAD/CAM system wasn't cutting it. As an example, he cites a part that they wanted to create a mold for, a carbon fiber transition tube that would go from the body work on the engine cover to the turbocharger. This was, essentially, a 90o elbow. On the end that would go to the turbo charger, the shape was a circle. On the other end, the shape was more complex, more ovoid. Willis says, "It wasn't super-complicated." But what they thought would take a couple of days to program actually took a week-and-a-half. What's more, they were never able to get exactly the shape that they wanted. They were limited by the software. This led them to perform some benchmarking. Which led them to select the Pro/ENGINEERING package. (Actually, Parametric Technology became a sponsor.)

One of the things that the team does in making changes to the chassis is to employ extensive wind-tunnel testing of a 40%-scale model of the car. Up until recently, traditional pattern-making processes were used to transform the designed parts, such as wings, into molds then models. This included making a series of cross-sectional templates and hand carving of wooden masters. Then it was making a mold, molding the part, and testing it on the model. If it performed well, then there was a repetition of the process. Willis points out, "Things have become so sophisticated on these cars that at the track we may change a wing angle just an eighth of a degree and that will change the way the car behaves." He goes on to explain that this hand work was such that there was never a high degree of certainty that what was designed was actually replicated in the part that was produced.

Now, they are machining molds using the CAD model as the master. Not only does this reduce the time necessary to make the mold by a third, but it provides assurance that the parts produced will be within the accuracy of the software and the tooling on the machine tools.

 

Better Designs

With regard to the performance of mechanical parts, Willis says that historically, when developing a new setup, engineers would have to rely on "basic experience, knowledge and gut instinct." Now at Team Rahal there is an assist that he considers to be a "significant advantage," which is the Pro/MECHANICA analysis module that is used. Not only does it use the same menu structure as the design software, but it is capable of helping guide the engineers in making the right decisions with regard to parts. The engineer ultimately makes the decisions, he stresses, but the decisions tend to be more accurate due to the software assist. Willis says that what they are doing now is designing the parts in CAD, then running an analysis on that design to see how the part will deflect and twist under the known conditions. Then, after they have determined that the part is structurally sufficient, they may run a structural optimization code within Pro/MECHANICA with the objective of developing a part that will be as light as possible (by varying wall thicknesses, varying lightening hole sizes) yet still perform as required. Boundaries are set, such as no stresses over 60,000 pounds anywhere on the part to assure performance and limits on the radii between any two walls or edges to meet the tooling limitations. The system will then run the calculations.

He contrasts this with not only the basic hand calculations that an engineer might have relied on in the past, but also standard finite element analysis packages which, he says, will provide stress contour information but require extensive remeshing as modifications are made to the part design. That requires time. And time is something that is always in short supply for the engineers and machinists at Team Rahal.

 

Why the Rolling Billboards?

The number of decals on the cars and patches on the racing suits of the drivers in CART racing is—assuming that things are going well for the team—high. These labels are for the companies that sponsor the drivers. In the case of Team Rahal there are two main sponsors—Miller Brewing and Shell Oil—and 17 additional sponsors. These companies provide resources—monetary and material—that help get the cars on the track.

Going racing is not inexpensive. According to CART, the following costs can be expected:

• Chassis: Starting at $450,000. Wings for a super-speedway setup: an additional $30,000. (Think about those numbers the next time you see one of the cars crashing.)

• Engine: On the order of $1.5- to $2-million.

• Wheels: Front wheels cost $1,000 each; rear wheels cost $1,500 each. It is recommended that a team plan to buy 10 sets of wheels for a season (in addition to the set that comes with the chassis).

• Tires: Figure around $150,000 per season (a set costs about $1,200).

• Spare parts: $150,000 for disposable parts and $350,000 for gearbox parts.

• Transporter: Not only must the cars get to the tracks, but these vehicles are machine shops on wheels. Getting one costs about $400,000. Of course, it can be used for more than one season.

• Team costs: Not only does this include salaries for the drivers and engineers, but food and lodging and travel, and office employees, and facilities, and...

Bottom line: CART estimates that getting a car into the PPG Cup Series costs a minimum of $2.5 million. AD&P