Conditions: Temperature ~80 degrees, sunny. Very windy with periodic strong gusts. Skies became cloudy as the session wound down. Thunderstorms loomed on the horizon as I left the track.
When I got to IRP I had to sign a waiver before they would let me in. After passing through an automatic gate, I drove out to the end of the dragstrip and pulled my car up onto the track. The RaceSafe Barriers soft wall system was already set up, and two late 80’s Dodge Dynasty’s (the test cars) were parked nearby. There was no one around, so I drove most of the way down the strip and turned it around for a hole shot. YEAH! About ten minutes later, Jim Emmons, from the Industrial Polymers Division of Poly Hi Solidur greeted me and we talked for a few minutes until Bruce Eide of RaceSafe Barriers arrived. I talked with both of them for a few more minutes until they needed to get back to preparing for the test. Bruce told me that he had recently purchased the two test cars at an auction. One had 200K and the other had over 160K miles. Neither were equipped with any special equipment except that one had a black box installed on the floor of the back seat. There was no apparent body damage on either car.
The walls are comprised of three layers: 1) A very smooth, durable polymer casing. It has a low coefficient of friction, 0.15; is resistant to UV degradation; it is very hard to break (not brittle), will not burn until ~600 F, and burns like a candle. The flames are easy to extinguish and do not give off toxic smoke. The material is non-toxic, and has 75% of the marketshare for hip replacements. It also is claimed to have good memory, meaning it will return to its original shape after a certain period of time. 2) N2 filled inner tubes, @ 30 psi. This provides a volume of air that can be compressed to absorb some of the impact. I asked if there was an optimum pressure and if they had discovered a significant change in performance with a change in air temperature. Bruce quickly points out that this idea is still evolving and that a better container for the air layer was being explored. They hadn’t determined an optimum pressure and said that the barriers do not generate much “bounce”. 3) A Styrofoam layer, ~1 foot thick. The casing covers the two inner layers and wraps over the wall, where it is bolted down. The casing can be cut to slide around the catchfence and not compromise its structural integrity. Also, the casing is in sections, so they need to be attached together. This was done by using small bungee cords at the bottom of the barriers. There were holes drilled in the casing for the bungee cords. The sections were overlapped about 6 inches, so that a car would not snag on the seams if it is going in the proper direction.
A group of officials had filtered in after another 15 minutes. Among them (spelling is questionable here) were Johnny Parsons, Brian Barnhart (IRL Director of Operations), Phil Casey (IRL Technical Director), a USAC official, an ASA official and two representatives of K&K Insurance. Anyone missing here? After everyone introduced themselves to the group, Bruce outlined what he was going to do. He was going to repeatedly run the car into the barrier with a glancing blow at speeds from 10-30 mph. The first car made it 4-5 times before suffering a flat tire. It was the consensus that the metal hook on the bungee cord had caused the flat. Also, the barrier had slid out of place a bit and was repositioned. There were also some distortions to the shape of the barrier. The test car, aside from the flat tire, suffered only minor scrapes on the RF bumper. It didn’t look like there were any dents, but the bumper appears to have been pushed in a little. The second car (the one with the black box) went through the same drill and lost a mirror after one of the collisions. Then it went once more at 40 mph, resulting in repositioning of the barriers again. After that, Bruce got out and discussed what was happening with the group. One of the officials wanted to see a sharper angle of impact ( ~ 45 degrees), so that was the next run. Bruce says that he wasn’t even looking at the speedo. He was watching the wall. I’m estimating that he was going at least 40mph. The impact broke one of the casing sections loose and sent it down the track. A couple of the inner tubes bounced around and the Styrofoam was damaged. It was not damaged through to the wall though. Afterward, I asked Bruce how the impact felt inside. He said that it was “a non-event” except for the airbag deploying. This concluded the testing. Everyone then began discussing what they had witnessed in little groups. The officials were hanging around together, but I went and talked to Bruce and to Jeff Hoffer, an engineer by trade, and currently the Business Unit Manager from the Industrial Polymers division of Poly Hi Solidur.
To sum up our discussions and my opinions: For the speeds tested, the barrier seems to work well as far as not snagging a car in a glancing blow. Obviously, there is room for improvement in how the casing sections are held together. The bungee cords are not a long-term solution due to the potential of puncturing tires as witnessed in this test. After repeated contact, even at these slow speeds, the casings needed to be repositioned – they would slide one way or the other to the point that they were not overlapping. This situation needs addressed before racing relevant speeds can be tested. Bruce insists that the casing needs to be in sections – this provides flex between sections as opposed to one long piece of casing. Also, it makes replacement easier since the sections can be unbolted very quickly. In the final test run at the sharper impact angle, it appeared to us that the rear passenger door caught the barrier after the initial impact had pushed the barrier in. There was a dent in that door at a height consistent with a very distinct anomaly in the casing. (Of course, the racecars do not have doors, so this should not happen.) The casing itself had some cuts in it (up to ~2 inches) which were likely due to the sharp edges in the sheetmetal around the passenger mirror. The casing also had some distortions in it and Bruce was interested in finding out how long it would take for the casing to return to its original shape. The damage to the car was relatively minor for a sharp angle impact at 40(+?) mph. The headlight was broken and there was some damage to the sheetmetal and some to the bumper. Very minor compared to an impact with the concrete at the same speed. In my opinion, these barriers are designed to primarily minimize the snagging of a racecar from a glancing blow. This is a step in the right direction. Finding a way to keep the barriers together seems like the next logical step, along with finding a better “air cushion”. Bruce and his colleagues at Poly Hi Solidur will be reviewing the test video and I suspect will be contacting F4SRT in the near future. I took a number of pictures and have provided captions. I hope this article has been informative. Please feel free to ask questions, as I may have overlooked some points in writing this up.
Picture captions:
Barrier.
Side view of Barrier Barrier logo.
One of numerous 10-30 mph glancing blows. (1st car) Bungee cord unhooked.
1st car flat tire/scratches. 1st car scratches on bumper.
JP, Phil Casey, Brian Barnhart (IRL) One of numerous 10-30 mph glancing blows. (2nd car)
Sliding section back in place.
Est. 40 mph glancing blow. (2nd car)
2nd car a split second after 45-degree angle impact.
2nd car - post impact photo.
Bruce returning. Damage to wall/Styrofoam.
Dislodged casing section. 2nd car R view
2nd car RF view 2nd car: Note the air bag and the strange dent in rear door.
black box in the 2nd car Bruce (in ballcap), various officials standing nearby.
