Indy’s 100th:Winning is the Sum of Many Parts | Part I

Posted on Friday, June 03, 2011 at 3:07 PM. Comments (0)

The Track

This past Sunday’s Indy centenary celebration was the perfect example of why the Indianapolis 500 race has survived for 100 years. It was unpredictable, exciting and the essence of what Indycar racing is all about!

Satellite view of Indianapolis Speedway

Satellite view of the Indianapolis Speedway

The original 2½ mile oval was paved with bricks, hence the nickname; “The Brickyard”. Dick Gail, the very literate former Racing Director of the Champion Spark Plug Co., called it “Grant Wood at speed.” Picture American Gothic and imagine a helmeted Parnelli Jones in the picture and you get his drift. Indy is simply a very old track on which very fast modern cars are made to adapt in order to compete. Unlike the Indianapolis Speedway, today’s ideal racetrack would be much shorter and have steeply banked corners.

100 years ago a 500 mile race on a track of this size posed unique challenges. The distance itself made simply finishing an accomplishment. Also the primary car design consideration was speed. No serious thought was given to fire prevention or safety equipment. Quite the opposite, it was felt that being thrown from an out of control car was preferable to staying in it. So survival was a factor.

Aside from instant fame, what really attracted entrants to the Speedway was the instant fortune that came with it. The event was the premier American motor race of the year and the purse was so big that entrants would modify otherwise uncompetitive dirt track race cars in an attempt to make the show and thereby win a piece of the purse. Qualifying and finishing guaranteed a handsome payday and would fund many a future race weekend, or purchase or fund the building of a newer and faster car. An entire field of purpose built Indy cars as we now know them, didn’t develop until the late forties.

Surprisingly, it is the original design of the track that 100 years later continues to pose the major challenge to competitors. Cars that travelled at 100mph on hard, narrow tires, had virtually the same problem turning quick times as today’s 250mph cars do on sticky wide ones. Indy’s long straights allow cars to travel into the corners with far more speed than the relatively flat turns will allow them to sustain. Drivers must find the proper balance of speed, power and grip that will allow them to skid, or more accurately, rotate the car so that it comes out of the corner with maximum momentum and prepared to accept the application of full power once again. Because the skidding process scrubs off speed, the wider the arc of the turn, the less the skidding and the higher the entrance and exit speed. Unfortunately, the wider arc, the greater the distance to be travelled and that represents greater time expended. The fastest time around Indy requires almost brushing the outside wall at the entrance to the turn with the outside wheel, clipping the inside edge of the track at the center of the turn with the inside front wheel and almost brushing the outside wall again at its exit. That compromise between the shortest distance and the highest speed describes the fastest way through the turn and it allows the driver to achieve a higher exit speed on the subsequent straight. Doing it consistently is the driver’s challenge.

Indianapolis 500 100th Anniversary logo

So today’s Indy cars have the same issue at the original racers. Where and when to lift off the throttle and where and when to get back into it? At one period during the evolution of the Indianapolis race car—the last days of the front engine Offenhouser powered cars—there was a short period where the tires and the car design had evolved to a point that allowed brave and talented drivers to go through Turn Four without lifting. Because cars qualified singly, everyone in the pits could hear the sound of the engine and knew when a driver lifted his foot from the gas pedal. Drivers like Foyt, Jones and Andretti were in demand because they could do it consistently whether or not they had the best car. They may be celebrated today by race fans for their wins, but they were respected in the pits for their talent and their ability to get the maximum out of a car.

Aerodynamics, tires and the suspension set-ups determine how well the chassis works. Wind speed, temperature and track conditions determine the adjustments engineers must make to the set up to maximize effectiveness of their equipment. That is the engineer’s challenge. The driver can also make his own limited adjustments to the car as the race progresses and conditions and/or competitors demand.

As the race progresses a building up of small pieces of used rubber scrubbed from the edges of the racing tires forms to the outside of the line or perfect arc. This pinches the usable line inwards and the outside wall no longer becomes the furthest usable boundary. The line where the marbles or loose rubber dirt begins, determines the outer line which becomes what drivers call the dirty area and which is visible as a different texture and gray in color. This gray area inhibits grip and the car, particularly in turns where there is sideways pressure, becomes uncontrollable and slides up into the wall as though on ice or marbles. This tightening of the racing arc or line means slower entrance and exit speeds and diminishes the actual racing surface on which cars can pass.

When Indy rookie JR Hilldebrand went into the last turn leading the Indy 500, he had one backmarker—a slower non-competitive car—between him and the chequered flag. He had two choices; back off, thus scrubbing speed, and follow the slower car through the turn on the clean line. Knowing that Dan Wheldon was not far behind and not having a car in his way, may have been able to maintain greater momentum through the turn and catch him before the finish line, Hildebrand chose instead to put two inside wheels on the clean line and two in the “gray” area and hope that his car would stick. It didn’t and he slid up into the wall and crashed. His slide took him across the line in second place.

The clean racing line is very narrow and at elevated speeds cars must have all four wheels on clean surface through the turns to perform safely.

JR Hildebrand learned that today. Dan Wheldon knew it.

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