Sweating the details in soap-box race cars

PLAYING AROUND

Clinic

May 05, 2002|By LOWELL E. SUNDERLAND

YOU KNOW how they say that baseball - and the cliche applies to a lot of other sports, too - is a game of inches?

Take your so-called gravity sports, for instance, those in which you start at the top and head down as fast as you can, courtesy of your equipment, your skill, and one of the forces of nature, gravity.

Fractions of inches and/or seconds sometimes separate winners and losers in sports such as skiing, luge, bobsledding, skeleton, some forms of cycling, diving - and soap-box car racing.

Participants in all of those events figure to have a lot more interest in aerodynamics than the athlete who merely plays with a ball. Because friction between one's equipment or clothing and the air, snow or water can add precious time to your performance and, thus, help determine whether you win or lose.

Still with us?

Today's snapshot concerns aerodynamics and the quest of one Howard County man, Mike Harrigan, to save time, measured in hundredths of seconds, when his sons, Ryan and Sean, race soap-box cars.

Dad builds the cars from kits and then refines them, but his boys steer, which, it must be added, Ryan, especially, is very good at; to wit, the 100 or so trophies he has collected by age 14 and qualification for the sport's national championships in Akron, Ohio, in July. Sean, 7, is a second-grader at Clemens Crossing Elementary School, and he is racing in his first event today in York, Pa.

But we're slipping off the topic. We've left out the Glenn L. Martin Wind Tunnel Laboratory at the University of Maryland, College Park. (You never know what's going to turn up next when you write about the sports we write about here.)

That engineering department feature of UM is one of relatively few places in the United States where the aerodynamics of cars (over more than two decades, a great many models of future Fords, we learned), among other things, are studied for a lot of money.

The "slow speed" lab, built in 1949, is capable of generating winds up to 300 mph. There, tests are performed on jet fighters, missiles, helicopters, locomotives, buildings, yachts, submarines - anything that flows through air, or water.

Mike Harrigan, who has been interested in racing cars since he was a kid, is so into soap-box racing that he contacted the Maryland wind-tunnel folks, thinking he might be able to get a little advice he could apply on his own.

But inquiry led to invitation, because, as lab director Jewel B. Barlow put it, Harrigan "had done his homework, in spades." Last weekend, the Harrigans and a racing friend benefited from the lab's operators needing something to show visitors on Maryland Day, a promotional fete for the university.

Thus, they got 2 1/2 hours of pretty exotic testing done free at a facility that ordinarily charges many a penny for the same thing.

In fact, jigs that earlier this year held the U.S. bobsledding team's vehicles - two of which won gold and silver medals in the Winter Olympics - during testing were modified to hold five soap-box derby cars before the heavy-duty fan was switched on.

Lessons learned? One thing, Harrigan said, was that stripe painted on the tapered, front sides of his older son's car could slow things down, at least theoretically, although maybe not at the car's top speed of 40 mph.

Still, who would have guessed a couple of extra grams of paint in the wrong place on a highly buffed fiberglass body might be important?

"The cars are pretty streamlined," said Barlow. "We were working with some pretty small increments." Even so, he also said the lab found the soap-box cars an interesting exercise.

Harrigan said he thinks this was the first time a soap-box car has been tested against wind in controlled circumstances since 1991, when some work was done at Texas A&M's wind tunnel.

Oh, bottom line, he also learned that, sweat as many details as he does on his sons' cars, the basic design of soap-box derby cars that all racers start with is pretty sound aerodynamically. And that's why hundreths of a second in a race matter.

Call the writer at 410-332-6525 or send e-mail tolowell.sunderland@baltsun.com.

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