The Physics of NASCAR by Diandra Leslie-Pelecky

When this first came out, I didn't pick it up, despite a glowing recommendation from Jennifer Ouellette, because NASCAR is one of the few things on ESPN that interests me less than baseball. I didn't really think I'd be interested in reading a whole book on the subject.

I saw Jennifer and Diandra on Bloggingheads a little while back, and she made it sound pretty interesting. And then I saw that she was giving a public lecture at DAMOP, and figured it would be good for airplane reading on the way down and back.

The Preface gives a nice description of how she came to write the book:

Absentmindedly flipping through channels the Sunday before Memorial Day, I happened to see a group of six cars rounding the corner of a track. Before I could flip to the next channel, chaos ensued. The back of one car wiggled slightly, and then-- WHAM! The car smacked against the outside wall, then careened back down across the track, taking out the other five cars. Brakes screeched, cars spun through the grass, and a giant cloud of smoke rose over the infield.

People like me go into science because we like understanding things-- or maybe it's better to say that it bothers us when we don't understand things. Why would one car, for seemingly no reason, all of a sudden hit the wall?

Books have been written for much worse reasons.

Leslie-Pelecky goes on to explain, well, the science that goes into making a race car go fast. The book is roughly divided into two parts (though there isn't a formal division)-- the first half outlines the basic science of engines and aerodynamics and car design, informed by visits to several NASCAR shops, while the second half focuses on one particular race team, the 19 car of Elliott Sadler, who she tagged along with for a couple of races, and openly roots for.

The physics explanations here are very good, and in several places, she actually comes pretty close to writing the sort of interesting explanation of materials science that I've wished for here (this shouldn't be surprising, as that appears to be her research area, broadly speaking). If you've ever wanted to know the difference between cast iron and other metals, I recommend chapter 4, on the design and construction of engines.

The later sections on Sadler's race season were weakened slightly by my utter ignorance of how NASCAR works-- I kept being distracted by passing references to the Byzantine system of points and teams and qualifying and sponsors and all the rest. It does do a god job of showing the science in action, though it does still seem as much art as science.

The one weakness in the book, at least from my perspective, is the lack of figures in some key places. There are a good number of figures in the book, but her DAMOP talk worked a lot better, for me, because she showed a lot of pictures of the cars and car parts she was talking about. There are limits to what can be put into print, though.

The book hasn't made me want to start spending Sunday afternoons watching people drive in circles, but it is a good, solid, pop-physics book. If you're even a casual fan of NASCAR, though, it's the sort of thing that might completely change the way you look at the sport. There's a lot of science going into the whole business, most of it stuff that we ignore in regular physics classes.

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"There are limits to what can be put into print, though."

No there aren't - the creationists have proven that....

Ah, so another thing you don't know is that the total horsepower of the engines of the 43 cars on the track at a NASCAR "restrictor plate" race like Daytona or Talladega is roughly equal to the total horsepower of the 2 cars at the line at the start of a "Top Fuel" NHRA race. Both total something in excess of 16,000 bhp. Curiously, the 20 cars at the start of a Formula 1 race also make about 16,000 bhp. Some sort of conservation law at work here ...

I would observe that I hope you teach that kinetic energy gets turned into heat in the brakes, and that overuse or lack of cooling can lead to red hot brakes and boiling brake fluid that can lead to having a "bad day" on a mountain road if not in a race.

But, on your main point, it is true that we don't teach hardly any non-linear physics during the first year of physics. The fluid dynamics of turbulence never appeared anywhere in any physics class I ever took, and many physics texts still talk about Bernoulli rather than Magnus when discussing the curve of a baseball. Nevertheless, millions of dollars are spent on computational and experimental fluid dynamics to improve one square inch of the rear structure of a Formula 1 car and much of the cheating in NASCAR revolves around trying to evade rules that try to make the aerodynamics of the cars identical.

Check out
for the regular examples of how those millions get spent.

PS - If you think there isn't some physics and engineering science behind getting over 1000 bhp out of EACH cylinder of a 500 (8.2 L) engine, think again.