Over the past two seasons, five stock-car drivers have died as a result of injuries sustained in head-on collisions with concrete retaining walls. All died of basically the same injury—basilar skull fracture. Adam Petty, Kenny Irwin Jr., Tony Roper, Dale Earnhardt and Blaise Alexander died because the safety systems in their cars were not up to withstanding the massive forces generated by frontal impacts.
The first thing that leaps out from the above is that none of the five were wearing any sort of head-and-neck restraint. Alexander had a foam collar around his neck, as required by the ARCA Series on superspeedways, but no HANS or Hutchens device. The second thing that leaps out is there was no source of information from which to draw to come up with a solution for this type of accident.
A full-fledged crash investigation was done on Earnhardt’s fatal wreck and the final report was released in August. Behind it came the initial mandates from NASCAR about its future in regards to safety. Beginning with the 2002 season, all cars in the top three NASCAR divisions would carry crash data recorders, the “black box” designed to measure impact loads and other data useful in compiling a database for future engineering fixes.
In October, NASCAR shocked the world by mandating the use of head-and-neck restraints for drivers in its Winston Cup, Busch and Craftsman Truck series, beginning at the Oct. 21 EA Sports 500 at Talladega Superspeedway. In years past, NASCAR had not even required the use of helmets and firesuits by participants, merely recommended they be used.
“NASCAR has worked closely with safety experts, drivers and manufacturers to address issues that led some drivers to feel that these devices might make them less safe,” said NASCAR Senior Vice-President George Pyne when the announcement was made. “NASCAR’s decision making drivers’ side windows wider and our educational seminars for drivers have created greater comfort with using these devices. The willingness of the manufacturers to work with drivers in addressing potential drawbacks and explaining benefits also has allayed drivers’ concerns.”
Much action promised Pyne was busy during the announcement in October, promising that the occupant restraint study promised in the wake of Earnhardt’s death was underway and the results would be implemented prior to Daytona in February. The study was undertaken by outside experts to study hardware, webbing and mounting of seat-belt systems. The accident data recorders have been tested under race conditions in all three top series in NASCAR and the program is also on line for introduction at Daytona.
A full-time medical liaison is being sought by NASCAR to attend every race and keep updated medical files on all NASCAR drivers. So is a full-time accident investigator.
NASCAR is also participating in a joint project with the auto manufacturers on the structural design of its racing cars as well as the implementation of energy-absorbing materials. It is also working with the Indy Racing League in its pursuit of soft-wall technology to further ease impact energies. Whatever fruit these investigations bear will likely be transferred down the line to racers across the country.
Private Companies Busy
As NASCAR was mandating the use of head-and-neck restraints, work continues by private companies on new seats and cockpit systems designed to channel impact energies away from drivers.
Butler Built Motorsports, headed by Brian Butler, has developed a new aluminum racing seat system for use in stock cars, while NASCAR and CART team owner Cal Wells and CART chassis builder Reynard are developing a composite seat based on the current Indy car technology.
At the end of last season Butler and Trevor Ashline of Autoliv Corporation put together a combination of new equipment, improved existing products and proper installation procedures and made a full display to help illustrate specific aspects of driver cockpit safety throughout all levels of professional racing. This system is designed to work in concert with head-and-neck support systems and helps enhance their effectiveness.
The effort produced a few new tricks in terms of belts and harnesses, mainly in the mounting hardware and specifications. The first change is the fact that the lap belts do not have adjusters. It is the misalignment of these adjusters that promote “dumping,” which can cause them to fail. The adjustment of the belt is done at the mount, where a weave-through plate system similar to the wrap-around design secures the belt in place. The second system change in the display seat-belt system involves mounting the seat plates to the chassis. The weave-through plate has a tab for the attachment bolt, and the seat plates are mounted to the chassis with the weave-through plate sandwiched between. The weave-through plate is allowed to pivot on a shoulder bolt like those in passenger-car seat belts. The mount maintains the proper load-path angle for the belt and strengthens the mount by placing the shoulder bolt in double-shear load.
The final component of this seat-belt system is the six-point belt and mounting arrangement. The two straps of the six-point never connect to each other and work independently to control the motion of each leg. The orientation of the six-point belts works to surround the leg 180 degrees from the point at which it attaches at the buckle to where it mounts. If the belt were to continue past 180 degrees it could promote lifting the driver out of the seat during a frontal crash. Any less than 180 degrees and the belt might not provide adequate anti-submarine control and allow the driver’s lower torso to move further forward.
The headrest unit was developed to aid the head-and-neck restraint systems the drivers must now wear. The sides of the headrest are specifically shaped and padded to slow head motion, keep the head from twisting and provide as much peripheral vision as possible. The back of the seat provides the mounting locations and rebound protection for the driver. This rather substantial unit holds a lot of force and must be mounted to the rollcage. The padding in the back of the head unit is unique to this system. Tests showed the force to the driver’s head on the rebound from a frontal impact could be nearly as great as that of the impact itself. Impact-dissipating foam and a section of visco-elastic polymer padding reduce the force to the head.
The seat also includes an integral leg brace and knee-knocker unit to keep drivers’ knees from banging together in a side impact.
Composite Seat Coming
The PPI/Reynard seat, which has not yet received NASCAR approval, offers the protection of composite materials with some added advantages.
What does composite offer that aluminum doesn’t? According to C&R Racing owner Chris Paulsen (who helped develop and will market the new seat), a lot. “The difference between the composite seat we’re developing and the seats that are in stock car racing today is like the difference between a Lamborghini and a Model T Ford,” he said. “It is basically like having an Indy car tub inside a stock car. It’s very strong structurally. To duplicate the strength we get out of these composite materials, in the shape we have them in, you would literally have to build an aluminum seat out of three-quarter-inch plate.”
The reason for this, Paulsen explained, is the fact composites can be baked in any shape needed. “When you pull something out of a mold, you have the ability to make any shape you want, so we have a proper design around the headrest and a proper shape on the curves in the rest of the seat. It has integral belts, which means the six-point harness is actually part of the seat. The belts don’t go through a hole in the seat like with aluminum. It’s all the same mounting hardware as with a regular Indy car. This is proven technology and design that has been around for many years. We’re not reinventing anything here.
“The composite seat has incredible strength without making the thing weigh 1,000 pounds,” Paulsen continued. “You just can’t duplicate that out of aluminum. The other big advantage of using composite instead of aluminum is that it retains its strength and it basically has a memory. It won’t yield to movement. An aluminum seat, as it bends out, it loses its strength to the point where it has none, nor does it return. Once it yields, it stays there. It just can’t duplicate the properties in aluminum that you have inherently with composite. It takes a lot more force to move it, and it snaps back.”
One aspect of the composite seat is its cost. “Several years ago, Eloisa Garza of EG Composites and I baked up a mock-up carbon seat for NASCAR to look at, at its request,” Paulsen said. “It was basically off a seat mold from a GTP sports car. All the drivers looked at it and could see the value of it. Gary Nelson, Steve Peterson and myself have had conversations about it once a year or so since, and they felt the cost involved was a little higher than they’d like to see. But with the problems they’ve had and the situation they’re in, it’s something they’re kind of re-addressing. Its cost is going to be way beyond what you’d pay for any aluminum seat, but there again, we’re basing these prices on modern-day times and materials.
“Quite honestly, when you look at the professional forms of auto racing—CART, IRL, Formula One, Trans-Am, American Le Mans—stock car racing is about the last frontier for the aluminum seat,” Paulsen said. “When you look at the premier racing series around the world, aluminum seats are behind times. There was a day when that was absolutely the best seat you could have, and before that was fiberglass. The aluminum seat is 15 years out of date, really.”
One of the questions most often asked about composite seats is will it stand up to the pounding of a NASCAR race environment? Paulsen said it most definitely will. “The thing is incredibly strong,” he said. “It’s going to take an extremely severe crash and lateral load to damage the seat to where it will lose any of its integrity. It would have to be way, way, way beyond what you can imagine. It’s got a lot of strength to it.”
Changing Ways
In keeping with the integrated harness system in the composite seat, the belts have cam-lock fasteners instead of the usual latch-link prevalent in NASCAR today. “We’ve been working with NASCAR on the harnesses, and among those discussions has been talk of bringing in the cam-lock rotary harness like they use in Formula One and road racing cars,” said Scott Gladstone, president of Sparco USA. Sparco is one of the world’s leading safety companies and provides equipment to many of the top teams in Formula One, CART and IRL, World Rally and other forms of racing. In NASCAR, Sparco clients include Bobby Labonte and Jeff Gordon, among others.
“The latch-lock harness has been used in NASCAR for a long time, and most drivers grew up with it, so it’s something they know and are familiar with,” Gladstone said. “It’s pretty frustrating for us. We’ve tried to bring up that there is an alternative in the cam lock. The cam lock doesn’t have a tendency to come undone. The latch-link lever weighs eight to 10 ounces, but tests have shown that it can unlatch under a load of six to eight Gs. Under the kind of load stock car drivers can expect during a high-speed crash, that eight-to-10-ounce lever suddenly weighs two to three pounds.”
One Discordant Note
One result of the October press conference was that NASCAR announced it was not considering the energy-absorbing “Humpy Bumper” from Lew Composites for approval. According to the Charlotte Observer on Oct. 18, 2001, NASCAR found the testing data supplied by Lew Composites to be “inadequate.”
“The data that is available and the testing that has been done do not allow us to draw any conclusions that are meaningful because of the speed at which the tests have been done will not allow us to,” said Pyne. “We have concerns based on our independent experts regarding composite fiber and its effectiveness in managing energy ... We have no data in front of us that suggests the Humpy Bumper would be effective in managing energy.”
Testing data presented by Lew Composites, which staged a crash test for the media at Lowe’s Motor Speedway in September, contradicts Pyne’s statement. In that test, the car hit the wall at 40mph, roughly four mph slower than the minimum impact speed figured for Earnhardt’s fatal crash.
“With all respect to NASCAR’s ‘experts,’ we obviously need to do a better job of explaining how this energy-absorbing bumper works,” said Lowe’s Motor Speedway President H.A. “Humpy” Wheeler. “The difficulty in understanding this bumper is that it is made of directional carbon fiber. Only five percent of all carbon fiber usage is directional. Therefore, only those who work closely with it really understand its remarkable ability to redirect energy.”
Wheeler noted that directional carbon fiber is the same stuff used to fortify the foot-box, sidepod and bulkhead areas of both Indy and Formula One cars in the past few years. “Its safety record, especially in high-speed crashes, is proof that it works,” Wheeler remarked. NASCAR has been experimenting with aluminum foam, which has some of the same properties, but is significantly heavier than carbon fiber.
