GM stylists really pushed the envelope during the early design-sketch phase, creating forw
Summing up the significance of the sensational new Stingray doesn't come easy. Clichés such as "evolutionary" or even "transformational" just don't cut it. They can't convey the scope and depth of the design and engineering efforts expended on its behalf. We won't go so far as to overstate the seventh-gen Corvette as "revolutionary" or a "paradigm shift." After all, it still follows the familiar formula of a bellicose V-8 up front putting its prodigious power to the rear wheels. It's the same configuration we've come to know and love—only more so, emphatically.
Since a single phrase fails to capture the new Corvette, over the next several issues we'll be devoting a considerable number of words to delineate various elements of its design and engineering—everything from aerodynamics to suspension, interior features to driving dynamics, and so forth. It's a substantial undertaking, but minor in comparison with the massive design and R&D programs that went into the car.
We've already covered both the Detroit debut and engine configuration of the 2014 Stingray in previous articles, but they only scratched the surface. So in this installment we'll be focusing on that surface specifically, and the forces converging to form the car's startling new body shape. Since certain elements are the subject of some controversy among both Corvette loyalists and detractors, we broached this feedback with Chevrolet's design department to hear how it's being handled back at HQ.
To get these insider perspectives, we went to a key source: Kirk Bennion, Exterior Design Manager for both the Corvette and the fifth-generation Camaro. While he's quick to acknowledge that it takes a village of designers to create a new car, his background and contributions to the Corvette are both substantial and varied. Besides crafting shapes for a vast portfolio of GM vehicles from the start of his career there in 1984, he's handled the Corvette specifically since 2005.
Here's an exterior-studio image illustrating the surface highlighting phase midway through
While Bennion's formal training includes a degree in industrial design, along with a minor in graphic design, he's also grassroots car guy. He enjoyed a five-year stint in SCCA amateur road racing, and he serves as a driving instructor for the National Corvette Museum in Bowling Green, Kentucky. So he's no armchair director, but rather both a wheelman and commander for the design studio's captain, Tom Peters. Bennion not only has a sharp eye for contours, but also the calloused hands to make those lines flow and perform.
Ditto for the design team in general, as they've all gone through Ron Fellows' Corvette Driving School and have a three-day ZR1 certification. In doing so, "They learn that what we do with the exterior design is really influential to the car, and especially influential to the car on the track," Bennion notes. "We're designing the slippery exterior, we're managing the lift, we're providing brake cooling, we're providing trans cooling. So we have a very important role. To experience the degree of speed, and the stress you're putting the car under at speed, contributes to our finding design solutions that are both functional and beautiful."
How long ago did Chevrolet begin working on the new C7? Looking at the overall design efforts, "We don't just start and stop the ideas," he says. In other words, there are multiple timelines for various design concepts. But he does point to a fundamental change in a seemingly prosaic yet critical component back in 2008: the radiator.
Rather than the "bottom breather" configuration of earlier Corvette models, experience on the track dictated a change in the orientation of the radiator to lean it forward. Along with a functional extractor in the hood, the new layout not only improves cooling, but also reduces both drag and lift. (This change would prove to be the first of many modifications born from the heat of competition.)
Early in the development process, this scale model was one of only a few selected for full
"In the last seven to eight years, we've seen many more amateur high-performance driving events," Bennion notes. "We will continue to make the Corvette interior and exterior more track capable right out of the box."
Here's one example of the designer's "clown suiting" technique, where each side of a fulls
Elaborating on the dynamics of this development process, he adds that, "We also work closely with the race team. We share our data with them, and they modify it for competition."
In the dialog between these two camps, the converse is true as well, in line with that old saying about competition improving the breed. We can't help but draw historical comparisons to the Cobra-skinning '63 Grand Sport, which started life as a typical Sting Ray, yet clearly became a whole 'nuther creature that in turn influenced further developments on production cars that continue even to this day. (Take one look at the hood louvers and cooling ducts on a Grand Sport, and you'll see modernized versions of them on the C7, among other similarities.)
Not long after reworking the cooling system, the entire C7 design program kicked off, with a call for concept renderings going out to all 10 of GM's design studios located in the far corners of the planet. Referred to as a "global sketch blitz," this was literally a world-class effort in both scope and vision. Nothing less would do, as Corvettes typically don't go through a standard three-year design cycle, but instead only change their look once every decade or so.
This clay model was created near the end of the design process, and shows all the surfaces
Noting the import of it all, Bennion observed that, "Any time you work on a Corvette, any Corvette, it's a big honor and a challenge. When you think about what Corvette represents and what our customers and racers do with it, we design the most optimal performance car."
Some 300 sketches poured into the studio. From there, eight different digital versions were created, and then just as many one-third-scale models, each receiving several weeks of digital and hand-sculpted refinements.
Wind-tunnel testing played a significant role in the early stages, in order to evaluate the aerodynamics. Those initial eight models were then whittled down to five unique themes, and computer analysis determined if each one hit the aero target. Commenting on this preliminary work studying the Computational Flow Dynamics (CFD), Bennion points out that, "It's a huge enabler, and there's a big learning bandwidth." Since this aspect is an involved subject on its own merit, with a high degree of technical precision, we'll be covering it in a separate feature. So for now we'll be focusing more on activities that took place inside the Corvette studio.
Transferring those initial renderings to 3D models became an acid test from a visual standpoint as well. What looks good on paper or a computer screen also has to work well in clay. In some cases, slightly different design themes were applied to each side of a model (called "clown suiting"), which allowed for quick visual comparisons. At this point, the design team evaluates the model by asking, "Does it have strength?"
Theme approval by upper management included (left to right, foreground) Kirk Bennion, Tom
In other words, does it meet the design goals? These included creating more drama in the front end, along with a bolder, more expressive side feature that would integrate with the overall sculptural form. And the back end would be markedly different from the previous generation as well.
Before digging into those details, though, the design team's first priority was to change the upper graphic. "We've had the same removable top, upright B-pillar and full-glass backlight ‘basket handle' since 1978," Bennion observes. Changing that was essential to creating a stronger, more compelling design."
Note the legacy influence for the front-end treatment on this early design sketch, with a
It's no secret that the design team kept an eye on the competition (note that in North America, Corvette is Number 1 in its segment, while the Porsche 911 is Number 2). At a recent Corvette presentation at the Petersen Automotive Museum, where we met with Bennion, he pointed out that the team reviewed the shapes and overall dimensions of similarly sized sports cars. In particular, one image showed an overlay of the C7's outline on that of a Porsche 911.
It takes more than a village to develop a Corvette. Here are all the members of the exteri
Other commentators have noticed close similarities of the profile with that of certain Ferrari forms, in particular the 599 GTO. Looking at the timing of various vehicle debuts raises questions as to which design actually came first. In any case, it's obvious that many sports cars echo familiar favorite themes, as there are certain evergreen elements that never lose appeal.
Yet there was a clear effort to create "form vocabulary"—design-speak for a fresh approach to sculpturing the shape. "We do have inspirational objects of study, like the YF-22 [fighter jet], which is very edgy, but is very full in its sections. You can see that on the body side of the Corvette," says Bennion.
Whatever the inspirations that might (or might not) have come into play with the new C7, one particular influence on earlier Corvettes would not be employed to the same extent: customer focus groups. Why so? When GM solicited input from Corvette owners back in 2000 and 2001 during the development of the C6, this approach initially had some merit, but there was one big drawback: information leaks. "The Internet has become too powerful," Bennion acknowledges.
To avoid the premature release of images of confidential concepts, internal clinics are now employed to keep a tight lid of security on these fresh design elements. (That said, Bennion adds that the design team does attend a full calendar of events each year, to ensure they stay closely connected with Corvette owners and enthusiasts.)
Creation of the styling model requires a great deal of precise handcrafting and shaping.
Getting back to those specifics, there was some fine tuning of the overall proportions, making the C7 a half-inch wider and lower than the C6, while keeping the wheels tight to the corners. The top edge of the windshield is also a tad lower (50 mm) without reducing headroom, and the trailing edge of the hood is slightly taller as well.
How about the exotic tail-end treatment that detractors criticized as being too busy or looking too different from earlier Corvettes? "We knew we'd run into some objections," Bennion admits. His response to them? "We wanted it to be more unique than anything you see on the road. You don't mistake it for any another car."
Getting down to even finer details, the structural architecture surrounding the hatch was modified. Also, premium exterior components include Carbon Flash black-metallic- painted bezels on the hood, black-chrome bezels for both headlight and exhaust, LED lamps, and bright-chrome inserts in the grille. Even the fascia badge and logo came under close design scrutiny.
Stepping back from the project, we asked Bennion which single design element he's most proud of. Surprisingly it isn't the aggressive front end, or the upper graphic and side cove, or even the rear fascia. (Though he finds the successful cohesiveness of all of them to be his favorite quality overall.) Rather, he points to those carefully crafted ducts in the rear quarters. That's partly because they drew the most attention as the last design element to be finished. Also, a great deal of effort went into ensuring a high volume of air flowed smoothly through them (an aspect we will address in our following feature on aerodynamics).
The large mirror on wheels helps the design team review the opposite side by making the fr
Through all the iterations and refinements, there was a pressing concern to ensure the new Stingray would live up to the Corvette name and legacy. Commenting on the early development phases, Bennion said the team was resolute: "We're not going to call it a C7 until we've earned that." At what point did the team feel they had? During each internal review by upper management—specifically, Ed Welburn and his GM Design leadership team—the momentum and energy grew steadily. Upon seeing the "wow factor" on people's faces, they knew they were close.
Yet even after the final fullsize clay model rolled out in late 2011 with the C7 appellation, close to being finalized, "...the design team was still was self-critical," Bennion says. "Design is never cut and dry."
Indeed, as Michelangelo once noted in a letter from 1549, sculpture is the art of "taking away" not that of "adding on." His many unfinished statues clearly show this groundbreaking process of taking away, or carving, as he labored to free the figure born in his mind from the confines of the marble block.
Exterior-studio chief Peters puts his finishing touches on a
In contrast, the new Stingray embodies not only artistic form, but also performance function, these two aspects operating together to create a dynamic machine with both style and substance—one that works and feels as good as it looks. Yet the car clearly has one thing in common with Michelangelo's sculptural approach: As the clay was applied, any impediments to performance were taken away as well. The result is a melding of art and engineering into a striking new Stingray.