<VV> Corvair steering shaft - the human spear: Engineer's observations (Long)

[NicolCS at aol.com]

I was involved with crash testing back in my days at Honda R&D.  It's really 
amazing to see a 35 mph barrier crash.  It makes no more sound than a large 
pop - like dropping a light bulb on the floor and you think " Well that wasn't 
much".  Then you watch the high speed film.  The engine flies forward to the 
barrier, then is pushed back into the firewall.  In calculations, the engine's 
length is subtracted from the available crush space - they don't "protect" you, 
in fact just the opposite.  It's all about crush space.  Corvairs look pretty 
good in that equation.  About the steering column:  It's not so much that the 
column moves, but that movement reduces the space available for the shoulder 
belt to get around to stopping your torso.  Nothing restrains your head other 
than the steering wheel rim or hub even with shoulder belts.  Rim contact is 
OK as long as it's on your forehead.  If your nose hits the rim it's bye bye 
brain.  Hub contact (hubs don't yield) is usually fatal. Most Corvairs don't 
have shoulder belts so the loss of space to the wheel due to rearward wheel 
movement doesn't make much difference.  I believe that any Corvair that's damaged 
to the point of the steering wheel shaft "spearing" them would already be a 
goner from other factors anyway - primarily the lack of a shoulder belt and an 
impact-friendly steering wheel.  Odd little fact: Cars with airbags have 
"stretchier" belt systems to more gently slow the torso and they rely on the airbag 
to help stop it.  Cars without airbags have belts that don't spool out as much 
in an effort to fully stop the torso.  Many airbag equipped cars also have 
little-known "rocket motors" on the seat belt reels to reel-in the slack so the 
belt can do it's job and restrain the torso. These fire along with the airbag 
deployment.

Another interesting thing to observe is the reaction of car's body parts.  
The roof bows up about 4 or 5" above the windows, then comes right back down.  
Ditto for the trunk lid, though not so much lift.  The quarter panels and door 
skins develop huge waves but seem to come right back to normal.  WITH a 
shoulder belt, the driver's head hits the steering wheel TWICE in 500ms.  It's 
actually shorter than that since the first impact occurs at around 250 ms.  Airbags 
are fully inflated in 180ms and are deflating through multiple 4" vents 
before the first impact. Anyone who says thier airbag got in the way so they 
couldn't see might not be remembering things very well.

The good news: Statistically, Corvairs don't see all that much road time and 
generally aren't in commuter or highway use so our exposure is low.  Also, 
Corvairs have lot's of crush space so they will probably do better in a frontal 
collision than the cars of the day.  Most crashes are with moveable objects 
which really lowers the impact severity.  The 35mph crash test is similar to a 
head-on with a same-weight car or a collision with an immovable object.  BTW in 
a barrier test, (I'm doing this from memory) the airbag deploys at 12 mph and 
the impact will total the car.  At 19 mph, with no restraints, the occupants 
will be killed. The safety test requires non-fatal results at nearly twice 
those speeds.

I know, it's all a bunch of Hooey...  (except that fatalities are a fraction 
of what they were in '66 despite twice as many cars, drivers and miles driven)

Them's the facts, AFIK
C. Nicol