Viewed from the side, the all-electric Jeep Wagoneer S has a silhouette like most two-row luxury SUVs, with a strong resemblance to today’s Grand Cherokee in the greenhouse. Step to the rear, though, and it's a different story: Hidden behind sail-shaped D-pillars, the rear window has a much shallower angle and longer taper than the typical near-vertical tailgate. A giant wing sits atop the D-pillars, creating the illusion of a boxy, upright SUV. It’s a nifty trick that gives the Wagoneer S ultra-slippery aerodynamics while maintaining a more formal shape.
“To hit the aero target, we kept realizing that we had to create a very tapered profile,” Ralph Gilles, Stellantis Chief Design Officer, told Motor1. “We had to taper it to basically a tadpole shape, and none of us liked the look of it. So the wing became a solution to keep the profile attractive and get the benefits of the aero so it doesn't spoil the design.”
As Gilles explained, the typical SUV shape punches a hole in the air, creating a wake of turbulence that drags rearward as the vehicle moves forward. A teardrop or tadpole silhouette helps to close the hole, guiding the air back together and minimizing turbulence. If Jeep wanted the Wagoneer S to maximize its battery range, designers needed to find a way to make it aerodynamically slippery.
The pass-through wing was something of an accidental solution. “Initially it was literally just there to look cool and carry the [rear-view] camera,” Gilles told Motor1. “We ended up twisting it and turning it and finding that we can make it guide the air behind the vehicle, improving the aerodynamics.” The result: A drag coefficient of 0.294, on par with a first-generation Toyota Prius, making the Wagoneer S the slipperiest Jeep ever made.
“The really sloped roofline is absolutely one of the biggest enablers of how we got the 0.294 [Cd],” said Alison Rahm, Vice President of Product Development at Stellantis. “It was a lot of work there to get the roof down and then be able to manage the air as it comes off the roof, which the wing lets us do.”
Engineering the wing was no small feat. “What I tried to do for a long time was to put a center touchdown to the roof, because it hangs so far out, and there's so much mass in it,” Rahm said, noting with a laugh that Gilles was appalled by that idea. “And then you've got the vibration you have to worry about. The digital rearview mirror camera is in the wing. So I had to make sure, as people are staring at the mirror, that it's not oscillating. Finding the right way to get the stability without making it ugly, without adding all this unnecessary weight [...] that was probably one of our greatest challenges.”
Rahm and her team made it work, achieving their aerodynamic goal and enabling the first all-electric Jeep to achieve a battery range claim of more than 300 miles. “It is beautiful,” Rahm said of the cantilevered wing atop the new Jeep. “I stare at the car and I think, thank God, we made it work.”
