rec.autos.simulators

Larry

That's entirely correct.

That's entirely false. The on-car camera on Schumacher's car shows NO
sparks, because at first it was thought that it might have been
suspension failure, so the footage from Schumacher's car was looked
at, which ruled that out, as a suspension failure would have made
sparks. There definitely were no sparks.

Well, yes and no. He was technically dead at the moment of impact, and
it was part of the broken suspension (still*** off the detached
wheel) that pierced his visor, but it's an unwritten FIA rule that no
driver should die at the racetrack, so they kept him alive until they
got him to hospital, and let his family see him before they let him
go.

Care to back any of that up with some references?

I had always assumed the steering column was the root cause, but the TLC
program highlighted some interesting evidence that I hadn't seen before.

Plus I'd have thought something as obvious as whether there were sparks or
not should not even be up for dispute ;-)

Malc.

Larry

WTF?  I just tried it again.  Started downloading, estimates 10 minutes to
download.  Maybe something on your end?

Eldred
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Never argue with an idiot.  He brings you down to his level, then beats you
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I finally got it.  I just clicked on the link and let the window sit there.
It took about 5 minutes, but the download dialog finally appeared.

Larry

Note that 1) Williams F1 admitted at the trial that the steering
column may have been *partially* broken before the incident, and they
were the defendants, so to disregard that is pretty big.

2) There was one lap of green flag racing before they started the lap
on which Senna crashed. The tyre temps (and therefore pressures) were
much higher the second time through Tamburello than they would have
been the first time through, and the speeds would have been the same,
so why did Senna get through the first time when his car would have
been even closer to the ground? Why did everybody else make it through
without any problems? Why, before or since, has nobody had a problem
with tyre pressure and ride height?

3) F1 cars are designed to 'bottom-out' at high speed and still remain
perfectly balanced, otherwise it would be impossible to run at places
like Brazil where the 190mph start-finish straight/curve is bumpy as
hell, and there are scratches and marks all down the racetrack into
T1. Also, when an F1 car touches the ground, it scrapes it. It doesn't
bounce up in the air, losing all the rear end grip (as the program
said).

If you are simply stating opinion, please say so, and whether or not your
opinion is actually based on personal expertise, or just what you read in
newspapers at the time.

Malc.

Ok, something in the middle(between you and the server).<g>  It wasn't on my
end - everytime I tried it, the download started right away.

Eldred
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If the car bottoms out, it will cause a sudden decrease in the amount of
weight that is on the tires, since at the moment of impact with the
tarmac that weight is now being supported by the bottom side of the car.
This sudden change reduces the amount of traction between the tires and
the surface of the track. If the car was close to the limit of adhesion
before it bottomed out, this sudden change might be enough to cause it
to lose traction and slide off the course, as happened with Senna's car.

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Todd Walker
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The car is physically not able to bottom out by itself. There is a
wooden plank on the bottom to measure wear, and if this is worn by
more than 1mm at the end of the race, the car is disqualified (1994
regulations). The suspension is therefore set up to allow this
clearance. The only way the car would bottom out is on a bump at high
speed.

If it was a bump, then the loss of grip from the tyres would not be
because the car was instantaneously touching the ground, it would be
because of the 'jump' the car experienced when it bounced off the
bump. Hitting a sudden bump would launch the car slightly, reducing
grip on all four wheels, especially taking into account the stiffness
of F1 suspension. This would make the car continue tangentially to the
corner (as happened with Senna), but the driver would instictively
turn the wheel into the corner, sensing this understeering effect. In
this situation, when the car 'landed' after the bump, it would either
continue around the corner as before, or it would snatch at the front
end and begin to spin to the left.

I say 'jump' and 'land' because the car would not become airborne in
this situation, considering the massive weight and downforce effect
(~2600Kg worth) on the car.

Assuming the steering column was intact, it is clear that Senna did
not steer, so the car would have continued moving tangentially after
it hit the bump. So that *could* be an explanation. Except...

1) Why did Senna not steer? He was braking furiously, the front wheels
were not locked, so why not steer? The first reaction of a driver to
an unexpected occurence is to try and steer, unless he is already
braking when the unexpected happens, at which point the first instinct
is to brake harder.

2) The bump required to cause this kind of loss of grip would have to
be massive (in F1 terms). At least measureable in centimetres.

3) The bump did not grow or shrink throughout the race, so every other
car on the racetrack would have the same effect happen to them. His
tyres were *not* down on pressure, so it's not a case of the safety
car having an effect. Why did nobody else even come close to having a
'moment' at Tamburello?

---

With regards to the steering column, some facts. These are all quotes
from the trial, acknowledged where possible.

"The steering column had been cut and a new element - which was not of
the same quality of metal [The parts were machined from two types of
compatible steel, T45 and EN14] or of the same diameter, being 18mm
instead of 22mm - was welded in. And it was where the new element had
been welded in that the column broke."

"There are three possible causes of the break - poor quality work, the
quick movement of the steering column and a too small diameter of the
joins between the three sections of the column." Tommaso Carletti, ex
Ferrari race engineer

"But I'm certain that the plane I arrived in yesterday had cracks in
it." - Frank Williams when told that his own experts had discovered
over 40 percent metal fatigue in Senna's steering column. Two
investigations from independent laboratories arrived at the same
conclusions. The steering column had signs of fatigue for 3/4 of the
circumference and for 40% of the section.

'At the end of 1976, however, he joined the Hesketh F1 team, working
on the design of the 308E for the two seasons before the team closed
down. By the time that was over he had acquired a taste for the
engineering challenges in F1 and soon afterwards found a job with the
newly formed Williams Grand Prix Engineering. He became Patrick Head's
first aerodynamic assistant and, working in the Imperial College
windtunnel in London, helped Head and assistant designer Neil Oatley
to produce the Williams FW07. The car made Williams a winning team and
Dernie continued to head Williams' aerodynamic activities into the
mid-1980s - helping to win three World Championships and playing an
important role in establishing the team's own windtunnel facility.
Later he designed the Williams active suspension system.'

So he's a reliably unbiased person to get your quotes from...

"Senna's car had power steering. Because it had power steering, one of
the things that they were measuring on the car was the twisting force
that he was applying to the steering column. Because they were
measuring that at all times, right up to impact, you can look at the
information off the car, from the black box, and see that up to the
moment of impact it wasn't broken."

I don't know whether this was said in this way deliberately or not,
but "... the twisting force that he was applying to the steering
column" is strictly true. The measurement of steering going to the
black box was taken just behind the wheel itself. Dernie's conclusion,
"... and see that up to the moment of impact it wasn't broken" is
inherently flawed because even if the steering column is broken, the
black box will register steering input. The hydraulics of the power
steering unit were fine also, meaning that it was working, so
effectively both ends of the column were fully operational, but they
can't say whether or not the connection (the column itself) was fully
intact, partially broken or completely severed.

And what conclusion do you draw from this?

You appear to be saying that the steering column 'obviously' broke, causing
the crash, but then go on to say that there was no way to know for sure,
just that it had evidence of metal fatigue.

My point is not to argue one way or the other, simply to point out that
there are very large grey areas which you appear to believe you have full
knowledge of, and I'd like to know whether you are actually the 'expert
witness' you believe yourself to be, or if in fact you are just guessing.
The court case cleared Williams, btw.

Malc.

The wooden plank was added to the cars after the Monaco GP of 1994 if I
remember correctly. The 1994 cars were essentially as close to the ground as
possible when Senna's accident occured. There was a minimum height, but it
was much less than after the plank was added.

the TLC document explains that he was trying to catch the back end of the
car which had lost its downforce because the car had gotten too close to the
ground.

--
Mika Takala