October 17th, 2011
In San Francisco they called them Rice Rockets — the small, mostly Japanese cars from the nineties that were outfitted with spoilers. It was always a sight that made me snicker– tilted, unwieldy, flat panels over the growling hindquarters of a little Toyota that probably couldn’t top out at more than 80 miles an hour. The ostensible point of the panels was to keep the car compressed to the road by the force of air pressure. Spoilers on these cars had as much aerodynamic meaning as furry dice dangled from the rear view mirror. But you get into cars running upwards of 130 miles an hour and the need for a down force becomes crucial. In a formula one car, there is as little space as possible between the surface of the road and the under-surface of the car. At speed, a little air gets under and it acts as a wedge. It lifts the front, and lets more air beneath, which forces the nose of the car upwards. Pretty soon you have less contact — or none — between the front wheels of the car and the race track. Then it’s all over but the obituaries.
That’s only part of the aerodynamic story. Drafting is another. Drafting is the practice of following another vehicle closely enough that it serves as a windbreak. Just nudge up close to the back wheels and you have power to spare — the front car is doing all the work. Time it right and you can burst out of the bubble and take the lead in less than a second. But just outside the bubble is dirty air. In skydiving we called it the burble (a coinage I like, combining as it does “burst” and “bubble”). Bicycle racers, even marathon runners, draft the front runners.
I had never heard the term dirty air, but in the course of watching yesterday’s crash footage (in which 33 year-old race car driver Dan Wheldon died) the term was used two or three times. So I did what intellectually curious people do, I went to Wikipedia. Both to learn about dirty air and Dan Wheldon. Today, all manner of horrors are learning opportunities.
(Soon, I hope, I will have learned how to wrangle WordPress and post images in the proper place).