Designing on the edge: how Ford’s Dark Horse SC took shape

By the time the Ford Mustang Dark Horse SC reached its final form, it had already lived several lives. The programme had been through three iterations, the clock had been running hard, and there had been no extra time on offer. The question put to Ford senior designer Aaron Walker, who created the winning sketch, had been blunt: Can you do this in the time we’ve got?

“That was it,” Walker recalled during a conversation on the sidelines of the Detroit auto show this January. “The programme didn’t shrink and it didn’t grow. We didn’t have a lot of time. We had to jump in there and make it happen.”

What followed was a compressed, collaborative sprint that brought design and engineering into unusually close contact. It was tense at times but ultimately productive – the kind of “good tension” that Walker believed pushed both sides to do better.

Walker said the relationship between design and engineering has shifted significantly over the years. In one crucial respect, he argued, the two disciplines now met much earlier in the process.

The hard points – the fixed, non-negotiable elements of a vehicle’s architecture – had defined much of what was possible. They locked in things like the shape of the grille intake, the amount of air it needed, and the lighting package.

“You couldn’t change them,” Walker said. “We had the lights, but when we modelled over them, we were a lot closer. Then we sent that model to the engineers and they had something really concrete to work with.”

Once a surface had been modelled and sent across, the conversation shifted to attachments, back surfaces and assembly. Walker described those B-side realities as the things that had “really killed us”.

“The back surfaces, attachment points, how parts had to go together – that’s where it got painful,” he conceded. “You got, ‘Oh, we still can’t do that shape because the back surface is getting in the way.’ So then you started tweaking.”

On the Dark Horse SC, there had been barely any breathing room for that iterative dance. With multiple design loops already behind them, Walker said there had been no time left for a slow, exploratory process.

"With the clay modeller I was working with, I had to jump in there and start hacking away at the model. And we got it really fast.” The modeller, Walker added, had been essential. “He was a master modeller. He was awesome. We couldn’t have done it without him.”

Despite the pressure of hard points and packaging constraints, Walker insisted that design still had to begin with emotion, not engineering.

Nowhere had that negotiation been more intense than at the front of the car, around the feature Walker called the “strongman graphic” – the bold carbon fibre element defining the face of the Dark Horse SC.

“That was such an important line,” he said. “We needed that dihedral-like form. But as we pushed it up, we kept hitting hard points. Attachments, mainly. And there was a cooler behind that, so we had to make sure we got the right amount of air.”

Body engineers had been embedded with the design team, allowing decisions to be made in real time, standing around clay and CAD terminals rather than trading emails

The shape needed to move inboard, but not so far that it interfered with the grille. It had also needed a plan-view angle so the part could be released from the tool – it could not simply run straight back.

“It had to have some angle to it,” Walker said. “But that proportion had to be larger than the proportion on the top. All of that negotiation – how much air we needed for the cooler, how much for the grille – it didn’t dictate the surface, but it informed what that shape could be.”

Take that feature away, and the car stopped reading as a Dark Horse, Walker argued.

“You might still have a Mustang,” he said, “but you didn’t have a Dark Horse. On this car, that big dark carbon fibre piece had to be bold. Even more bold than the regular Dark Horse.”

When asked how the team had ultimately resolved the clash between design intent and hard points, Walker’s answer had been simple.

“We just came to an understanding,” he said. “We understood the B-side better. They understood what we needed better. A lot of back and forth. A lot of communication. A lot of tweaking. And we made it work.”

Ari Groeneveld, chief program engineer at Ford Performance, said the breakthrough on the programme had been physical proximity between the teams. 

“There was no time for emails and phone calls,” Groeneveld said. “It was, ‘Here’s the clay. Here’s my CAD terminal. What do you want to do?’ We could define zones, see what we could touch, and where we could go.”

With something as potent as the Dark Horse SC there had always been a risk that capability would overwhelm character

That proximity had proved crucial as the team worked through the front-end packaging challenges.

“It wasn’t that we said, ‘We’re going to do this and everything will execute fine,’” Groeneveld said. “It was about going through the detail. Fitting the headlamps. Addressing the cooler opening. Looking at the sketch on the wall. What did the character have to be? How did we execute that? And what were the functional needs?”

With something as potent as the Dark Horse SC, he added, there had always been a risk that capability would overwhelm character.

“There was passion on both sides,” Groeneveld said. “And that’s what made it work. It was about pushing and challenging each other: 'Let’s look at the CAD. This is where I am limited. This is where you could go. Give me something'.”

One of the most technically demanding areas had been the air inlet feeding the supercharger. “That path ran all the way through the body,” Groeneveld explained. “We wanted it breathing as best it could. The challenge was defining how far we could open it, and where, without encroaching too much on metal or interfering with other components.”

It had been a difficult balance to strike. “But we got there.” The result, both men agreed, had been worth the effort. The Dark Horse SC had looked exactly as it should. “Sinister,” Groeneveld said, smiling. Walker concurred. “Bold. Muscular. Sinister. That was the goal.”