Countdown: The Last Checkered Flag

Sunday, August 14, 2011

Lap 86

18 Hours of ChumpCar 2011 Bonus Material

I drove off the track on lap 86 of the 18 Hours of ChumpCar race held at Texas World Speedway (TWS), on July 23-24, 2011. It wasn’t remarkable that I drove off of the track, I had already done that twice in the same stint. What made this off-track excursion remarkable was the fact that, until I was actually off and into the grass, I had no idea that anything had gone wrong. I thought I had negotiated Turn 3 correctly and that I was driving straight towards Turn 4. Suddenly, I found myself flying straight off the track with my foot still planted on the accelerator! It really shocked me. The major factor in this accident was that it occurred at night and the lights on our car were abysmal. I could barely see the track at all. The other thing that makes the off remarkable is that it destroyed the car. So, what happened?

Leading Theory

I found the answer with the help of Harry’s GPS Lap Timer, which is an inexpensive, but very nice little data acquisition system that Andrew Bianchi bought and which we evaluated during this race. One of the nice features is the ability to overly the GPS plot lines onto Google Maps. So, the end of Lap 86 looked like this:

1. It clearly shows that I drove straight off of the track. I was not trying to save a botched turn.

2. I was going 64 mph when I went off, which also supports 1. To end-up on the inside of the track, because of a botched turn, would have meant an almost inconceivable tank-slapper that would have burned a lot of speed. 64 mph is consistent with my speeds at that point on earlier laps.

3. Most importantly, it gives a clue to the most plausible explanation for what happened. In the dim light afforded to me, the road repair patch at the track-out of Turn 3, looked to me to be the edge of the track. The road patch mimics the size, shape, and shade of the actual track-out point (A vs. B).

Assuming that on a previous good lap, I hit the track-out point of Turn 3 (A) correctly, we can adjust for the GPS inaccuracy of the “Correct Line” in the illustration above, correcting it so that the line intersects that track-out point. If we adjust the Lap 86 plot accordingly (intersecting B), we can see what happened. I thought the road patch was the edge of the track and I thought I was a few meters to the left of where I actually was. After finishing the turn, I wanted to take a defensive line on the inside of Turn 4, so I pointed the car to the right side of the track, but I immediately ran out of track, even sooner than the uncorrected GPS plot line shows.

If it seems like I’m working too hard to analyze this event and hypothesize a reasonable causation for it, it’s probably because I don’t like the alternate theory.

Alternate Theory

I suck at driving.

Site Survey

After the race, Peter Haas took Kang Lee and myself on a site survey to see if we could find any clues that would explain the extensive damage to the car.

In this photo, we can plainly see the tire tracks going off into the field. While there are some minor undulations, overall the field seems fairly level. Certainly, it seems like it should be no problem for an Audi quattro with good ground clearance.

Oh. Kang finds the problem.

The right-front tire went into the culvert and the cow-catcher dug into the ground. The cow-catcher then folded-up under the car and most likely broke the oil pan and oil cooler. If I had been one meter to the left, nothing would have happened. I would have slowed the car, driven back onto the track, and continued the race. Ten minutes later and I would have had help from the early morning sunlight and the accident most likely would not have happened. Heartbreaking.

A piece of the oil pan and the resultant oil spill.

Jimmy works the accident scene. Photo: Kang Lee

The ground-catcher. Photo: Kang Lee

Here is the cow-catcher on the car. It was designed to help hold the front-end of the car together as well as provide some protection from minor offs. Without a skid plate, it dug into the earth, bent back, and caused critical damage to the car. A point of team debate – the nosecone provided a skid plate for the cow-catcher. How did the decision to run without the nosecone affect the results of this accident?

The damaged cow-catcher and a gallery of other stuff that I busted.

Notice the tight door seam tolerances. They exceed normal German build quality so much that the passenger door no longer opens. Also, the wheel does not belong there. It should be centered in the wheel well. Got caster?

A Tribute

Even though we finished the race in this car, everyone agrees that it is finished. This car was totaled years ago, but through the will and hard work of our race team, the car lived-on giving the team years of fun and adventure. It was a good car and she will be missed.


No comments:

Post a Comment