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Tech: The Air Force

Lessons in the science of aerodynamics in Dirt Late Model racing
Text and Photos: Jeff Huneycutt

These days it’s only the most ignorant of Philistines that believes aerodynamics only apply to asphalt racing. Dirt track race cars, especially the Late Models, have come a long way in the last few years. Yes, Sprint Cars make excellent use of aerodynamics with their absolutely massive wings. But Sprint Cars have mostly looked the same for decades.

Dirt Late Models, however, have evolved quite a bit in the last 10 years. Yes, Late Models still retain the same wedge shape of their predecessors from the previous decade, but there’s actually been a great deal of development on these cars. The changes, at first, may appear subtle to the untrained eye, but you’d better believe practically every angle and crease is created for a purpose.

So we thought we’d take a closer look at some of the tricks that Super Late Model chassis builders and race teams are currently employing. Most of these came about because of a recent trip to the shops of Barry Wright Race Cars to check out Wright’s new Icon DLM chassis.

Driver Jonathan Davenport, who is returning to drive for Wright after a very successful couple of years with other teams, was also in the shop, so we had an opportunity to hit him up for some info as well.

Both Wright and Davenport said that creating downforce in the Dirt Late Models is critical these days if you expect to be able to keep up with the competition and have any success on the track. Interestingly though, Davenport says that as a driver he doesn’t need different aero tricks depending on whether he’s driving a Super or a Crate with approximately half the horsepower.

(The suspension setup is a different story, however.)

The difficulty, when it comes to developing a comprehensive aerodynamics package for a dirt track race car, is it’s quite difficult to gather useful data from a wind tunnel test.

Wind tunnel testing is no longer prohibitively expensive, and asphalt teams can take advantage of them to fine-tune their aero packages. But it isn’t as effective for dirt teams because the cars are yawed so extremely through the turns that it is impossible to replicate the conditions in a wind tunnel. They simply aren’t designed to test cars that are practically sideways.

Aerodynamics on the straights simply aren’t important compared to the need to create downforce to help keep the car planted through the turns.

“These cars are so big now,” Davenport adds. “They move a lot of air. Going through the turns they yaw so much that they take up about 15 feet of track. So you want to look at how they react when following other cars. You’d love it to lead every race from the green flag to the checkers, but we all know that isn’t going to happen, so how the car handles in traffic is important.”

Check out the photos and tips we’ve gathered for you. Much of what you see comes from our conversations with Wright and Davenport, but others are from what we’ve gathered by just keeping our eyes open at the race track–so don’t blame Wright if everything doesn’t work for you.

Wright also allowed us to photograph practically anything we wanted of two new cars going together in his shop. Both are Wright’s new Icon car design, and the #49 that is practically complete is a customer’s car that Davenport borrowed to win Swainsboro Raceway’s $20,000 to win Turkey 100 Crate Late Model race over Thanksgiving weekend.

That, by the way, was Davenport’s first race back with Barry Wright Race Cars, so it appears from the outside that this matchup will be paying big dividends in the future.

Source
Barry Wright Race Cars
(864) 463-4711
www.barrywright.com [2]