It may seem strange that on a race track where 43 cars can beat and bang on each other for the better part of three hours that the one thing nobody can see sometimes makes the most difference in who gets across the finish line first.
Yet that’s the case almost every week in the NASCAR Sprint Cup Series as the air that gets buffeted around from stock cars whizzing around at close to 200 miles an hour provides grip and speed for the one in front while those stuck in the pack struggle to overcome its turbulent force.
That’s why when it came time to start designing the 2013 NASCAR Fusion stock car that will compete next season, aerodynamics was paramount to its development.
“The aerodynamics for the development of this 2013 Fusion is very important because we want to put a new car out that is very similar in downforce, drag, and balance to the current car we’re racing, so we end up with a smooth transition from the old car to the new car, ” said Ford Racing Aerodynamicist Bernie Marcus. “The main objective is to put more brand identity into the race car, so what we’ve been trying to do is capture as many of the 2013 production Fusion character lines as we possibly can and incorporate them.”
In order to satisfy the aerodynamic and design equation, Ford Racing utilizes a number of different wind tunnels throughout the United States. Marcus, who has served in his role with Ford since 2001, has done a significant amount of work on the 2013 NASCAR Fusion at the Auto Research Center (ARC) in Indianapolis, Ind., which is a 40-percent scale model tunnel. He’s opted for that method for multiple reasons.
“First of all, the accuracy level is much better than the static floor tunnel at Lockheed (Marietta, Ga.) because here we have a rolling road that gives much more accurate results and translates onto the race track much better,” he reasoned. “The second benefit is we’re using 40 percent scale models and they’re actually more efficient, cheaper to operate and build and use during the development process for this new car, while not detracting from any of our current race teams.”
After parameters for the new car were agreed upon by the manufacturers, wind tunnel testing began in August 2011 and since then, the 2013 NASCAR Fusion has gone through at least a half-dozen sessions that generally last 8-10 hours a day.
“We’ve also been to some full size tunnels at Lockheed and AeroDyn (Mooresville, NC), and those tests verified what we developed here at ARC in the scale model,” said Marcus. “We also had it on the test track to verify because the way things operate in the wind tunnel world is that quite a few things we develop don’t ever see the light of day on the race track.
“The scale model enables us to go and pick out the areas of the car that we want and create the shapes with the correct downforce, balance and drag levels. Once we determine those things in scale, then we go ahead and make full-size car parts that we then test at other wind tunnels before submitting to NASCAR.”
Even though the current car and 2013 model look markedly different, both drive similarly because the new Fusion has more drag due to a much sleeker greenhouse, much like the production counterpart, which blows more air onto the rear spoiler. Otherwise, the downforce and balance levels are very similar.
And while the 2013 NASCAR Fusion will likely go through some minor changes as NASCAR does its best to ensure all manufacturer models are equal, Marcus is encouraged by the early results, which included the first on-track test at Homestead-Miami Speedway in early February.
“The correlation between the wind tunnel and the race track was very good,” he said. “In fact, Matt Kenseth drove the car and said he couldn’t really tell the difference between the current car and this new car. That is really the whole object of this exercise from a technical standpoint because it’s crucial that the wind tunnel numbers transfer to the race track.”
Ford Racing PR
