Car seat technology keeps drivers anchored
June 18, 2013, Ron Lemasters Jr., NASCAR.com
For most of us, the only seat we care about is the one we bought to sit in at the race track, watching NASCAR’s stars and cars on a Sunday afternoon -- or Saturday night, now that it’s summertime.
It’s ours, and it’s where we do our thing: celebrate the sport and cheer on our favorite drivers.
For drivers, it’s a lot more than that, as you might well imagine.
Back when some of us more mature NASCAR fans first smelled the exhaust and tire smoke, a driver’s seat was whatever it needed to be; usually aluminum, they were individual in preference. Some drivers preferred padding like an old bus seat. Some did not. Some wanted a headrest. Some did not. The belts were individual as well, mounted the ways they teams knew how and were familiar with.
The evolution of seat technology has gone light-years ahead over the past decade, and they have less to do with making the driver comfortable -- although that is a consideration -- than keeping them safe.
It started with the new millennium, amid a terrible period where four drivers died as the result of injuries sustained in frontal crashes. Their tragic deaths spurred the development of safety equipment that could stand up against heavy impacts.
In addition to the head-and-neck restraints that were mandated by NASCAR in the wake of the tragedies, many advances in seat technology were made in the years following Earnhardt’s death. Carbon-fiber technology, readily used in open-wheel formula cars for many years, was one choice; aluminum seats were beefed up to hold drivers in place much more snugly than the old-style seats did.
Whether carbon fiber or aluminum, seats sprouted headrests on either side of the driver’s head, covered in impact-absorbing hard foam in various thicknesses.
Contrary to common thinking, the head does not go straight forward during an impact. The heaviest part of the driver is the head, partially due to the weight of the helmet. In an impact, the head reacts directionally and then goes forward, somewhat in the shape of a comma. The padded headrests minimize this movement, stopping the head from moving sideways and lessening the frontal impact.
The harder foam is able to take a harder initial impact and slow the head and helmet down at a safe rate for the driver. In other words, you can’t squish it with your fingers, but the lining decompresses under a significant force -- similar to the foam used in the Safety Barrier walls that surround today’s speedways.
Seat tech is all about making sure the driver survives the impact. It’s working, too. Look at Elliott Sadler’s impact a couple of seasons ago at Pocono, where his Ford came to a stop so fast the engine popped right out of the car and bounced down the backstretch. Sadler crawled out of the car, out of breath from the impact, but otherwise hale and hearty.
The key is to slow down the impact before and as it reaches the driver. A hard initial hit is survivable, provided there’s time for the body to catch up enough to make impact sustainable. During the aftermath of a hit, an impact graph should look like a square. Impact energy is measured in Newtons, and if you get above 400, you’re likely not surviving it. The initial hit will drive the spike straight up, but as the safety measures built into the car take effect, the cars slows the impact, then bleeding it off.
All of this happens within nanoseconds, and they count.
Carbon-fiber seats are very useful in this regard. First, they are molded as a single piece, essentially a padded cocoon made of directional carbon fiber. They’re nearly as strong as aluminum, but are not welded. Aluminum seat tech is progressing rapidly as well, and many drivers prefer the aluminum to carbon.
In carbon seats, the belts are often integral to the seats, with mounting points baked right in as the carbon fiber is hardened, so the belts don’t run roughly over insertion points and potentially fray as they used to. Wider belts are also used to stop more of the impact, and the HANS device helps to slow down the head and keep it anchored to the neck. Aluminum seats, like those produced by ButlerBuilt, ISP and LaJoie have their strengths, working along much the same lines.
The new seat components have combined to keep NASCAR drivers safe inside the car. Along with the adaptations from the Gen-5 (CoT) and the continued development of the Gen-6, NASCAR has hit upon a system that works, used in combination with soft walls.
That means we can stay in our seats, cheer lustily for whatever car your choose, without concern that a beloved driver’s seat may not be enough.