Here is a "commentary" that came from
our email discussion list. It is for your consideration regarding the use of 5
point harnesses or 6 point harnesses. This is nothing more than a personal
commentary regarding harness systems. Neither the author nor opentracking.com
assumes any liability for the view expressed. You and only you are responsible
for the safety equipment you select. Research for yourself and make decisions on
what is best for you!
"SAFETY ISSUE
COMMENTS"
Author- Brad
Barber, January 01, 2002
Friends,
I got this from a rallying friend regarding in-car safety issues. More
and more, it is leading me toward replacing my sub belt with a 6 point
style submarine belt. After seeing the film shown by Jim Downing at VIR
last year and now this I plan to make the change as soon as I can.
" .. safety seminar put on by Detroit Region earlier this year, right
after Earnhardt's death:
The main speaker was Dr. John Melvin, a bio-mechanics expert, who
headed GM's racing injury research team from 92 to 98 and is now a
consultant to all the major racing sanctioning bodies. They spent most
of their time analyzing Indy car crashes, but their findings are of
importance to all who race/rally. Here are some highlights:
1. The HANS device is the ONLY safety item that prevents the basil
skull fracture that keeps killing our friends in NASCAR, for example.
The big problem is the cars are now so stiff that the energy level
transmitted to the driver is much higher than it used to be. Indy cars
are even stiffer but all the flying carbon fiber dissipates a lot of
that energy.
The mechanics of the event have the torso stopping from belt tension
but the head keeps moving forward until it stops; that is when the neck
and spine are rotated parallel to the impact direction and it stretches
tight (OUCH!!). What has saved many drivers lives before the advent of
the HANS was the steering wheel...yes that's the key. The head will hit
the steering wheel and stop before the belts have completely stopped the
torso. This prevents the whipping effect. His best guess as to the
Earnhardt episode was that the broken lap belt (improperly installed)
caused his body to rotate right and his head MISSED the wheel. The whip
got him... He also said that in production type racecars like ours,
the crumple effect really reduces the likelihood of hitting hard enough
to be the recipient of this type of injury. In rally, we tend to have
lower speeds and "semi-movable" impact objects like trees. Hitting a
concrete barrier @ 100+ mph has much greater energy implications.
Having said that, I still think that a HANS might be a good idea in
rallying. Check with Mark Utech to see how he liked his.
2. Belt lengths should be kept as short as possible! I specifically
asked John about this one because I see all the WRC guys with the 3 mile
long belts. What people need to understand is the darn belts stretch a
bunch even when they are short! You should have seen the belt stretch
on the Indy tub lab crashes John showed. Long belts have other
implications. If you hit hard forwards your body will be off the seat a
bunch and if you then roll, your body will not be properly supported
which can cause other injuries. Think about it. Just because the WRC
is the pinnacle of the sport does not mean they truly understand this
stuff. John said some of the worst belt mountings he has ever seen were
in F1 cars. He also said he doesn't understand why the WRC guys do it
that way.
3. Racing seats should laterally support your shoulders, NOT your ribs.
Your ribs are not meant to take the punishment of a sideways input.
Good seats support your shoulders and put the lateral load in there.
That means all you guys with the aluminum seats that only have rib
support could seriously hurt yourselves under the right conditions. He
had nothing good to say about them. There is still a lot of debate over
mounting to the cage or not. Depends on the situation.
5 point harness 6 point harness
4. NEVER use 5 point harness. Use a 6 point with the anchors mounted
rearward of where your buckle ends up. The best way is to lay the sub
belt on your seat and mount it to the same place as your lap belts. The
idea of the sub belt is not really to keep you from submarining. It's
real use is to stop the forward motion of your torso. To do this the
sub must be stretched opposite to the direction of the force (the idea
that you can't push a wet noodle). The closer you mount the belt to the
horizontal direction, the sooner the system tightens up and stops your
body. By actually sitting on the sub like I mentioned, it acts like a
parachute sling making the belts very effective. I have tried this on
the Supra and found it a little uncomfortable at first, but I got used
to it. Of course I then crash tested the set-up and found that my belts
held me in place very well, even hanging upside-down!
5. The cheapo $3.00 roll bar padding is only good for soaking up blood
after an impact. It is too soft to absorb any serious impact. The only
kind to use if SFI approved stuff that goes for $15 for 3 ft. It has a
much higher density and hurts when you pound your fist into it. But it
is designed for the kind of impacts that you have it there for in the
first place. I redid all of mine and it cost me about $120. Cheap
insurance.
6. Steering wheels should be deformable. Any of you guys running a
Grant or similar "dune buggy" style wheel that has a steel rim under
foam padding are destined to break your forearms/wrist/hands. I know
you are out there because I have seen them myself. Get rid of it and
spend $150 on something decent that will not hurt you! Nuf said.
Whew. I feel better now. I can only hope that you will take some of
this stuff to heart. I'm no safety expert, but I am an engineer.
Everything this guy said made sense and could be backed up with
science. I have changed a bunch of things on my car and feel good about
it. I just wish all of you could have been there to hear the good
doctor. The sport would be a safer place."
-- brad barber
peace. love. track.
bradrx7@bradbarber.com
