Corvette Wind-Tunnel Testing - Aero Evolution

Has More Than A Half Century Of Corvette Styling Evolution Improved The Car's Performance, Or Is It All Just For Looks?

Jeff Huneycutt Apr 16, 2009 0 Comment(s)
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When the headlamps are raised, the C2 becomes a much different car. The vertical wall created by the headlights not only causes drag, but notice how the airstream separates from the car and doesn't reattach until midway up the hood. The area between the smoke and the car is a low-pressure zone that causes lift at the front wheels. This photo (along with all the smoke tests) was taken with the wind blowing 35 mph; it only gets worse as the car moves faster.

Interestingly, although it's the smallest overall, the first-generation Corvette has the greatest frontal area of any of the cars we tested. As you might expect just from looking at the more angular body lines, it also has the greatest coefficient of drag area (CDA) at 10.11. Surprisingly, it didn't produce the worst lift numbers. While the C1 recorded 124.6 pounds of lift at the front end (with passengers), the C2 recorded a higher 146.0 pounds of lift, substantially increasing the lift by 21.4 pounds. With the C2 headlights up, the lift increased another 7.2 pounds to 153.2, the highest lift numbers of any Corvette in the tests.

Although the first iteration of the Corvette doesn't fare well aerodynamically against its younger brothers, Eaker says the design is actually very effective compared to its contemporaries. "It's really impressive what they were able to do with those early Corvettes," he says. "Given the technology available at the time, coming up with a good aerodynamic package would have to have been a lot like watching a baseball game through a knot hole in the fence where you can only see left field and trying to figure out what's going on everywhere."

Generation Two
The next generation of Vettes, the C2, was produced from 1963 until 1967. This is the famous Stingray designed by Larry Shinoda. Our test car was none other than a '63-the only year of the famous split rear window-owned by John Meadows. Again, the car was all original with a 327 engine and four-speed transmission.

The C2 Corvette is the first with hide-away headlamps, so we tested with the lamps both down and up (with passengers) to see how that affected performance. As you might expect, running with the headlamps up increased drag considerably, increasing the CDA by 0.50, but it was worse in other generations. "Headlights are a necessary evil," Eaker says. "They can ruin the look of a car and aren't usually good for aerodynamics, but driving at night is already tough enough, so we don't want to get rid of them. Creating hidden headlights was one of the best-available solutions at the time, and it really became a Corvette trademark until this latest generation."

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The C3's smoother contours help the air follow the body of the car much more closely, but the split at the nose is still very high.

The C2's overall look is much sleeker, and the fastback reduces both drag and lift over the rear wheels at speed compared to the C1. The change in appearance is so dramatic, however, you really don't need a multimillion dollar wind tunnel to tell you that the second-generation Corvette is a vast improvement over the first.

Generation Three
The Corvette C3, like just about everything else produced in the '70s-with the possible exception of all those Charlie Brown specials-feels a bit dated. But slowly, the third-generation Corvette, produced from 1968 until 1982, is beginning to be accepted as a classic instead of a poorly engineered sports car with more bad taste than horsepower.

It's true that this generation of Corvette struggles in comparison to the other generations. The quality of materials often isn't what you'd expect. The engines were anemic (in 1975 the base 350 was rated at 165 hp) and the handling also dipped, as the cars gained weight thanks to the addition of catalytic converters, 5-mph bumpers, accessory packages like air conditioning, and other factors.

Eaker says you shouldn't completely blame Chevrolet's engineers for the lackluster image of the Vette in the '70s. "Those Corvettes are really a victim of their era," Eaker says. "In the '70s, society began demanding things of cars that it never had before-such as collapsible bumpers, better fuel economy, and less-polluting engines. The technology available at the time just wasn't able to keep up. The C3 wasn't as much fun as the C2 mainly because it had to do so many more things-like actually protect you in a crash."

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