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#51 kayemod

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Posted 22 February 2014 - 11:12


All of the "conspiracy" theories started ... now being looked at as "missing evidence". It was a racing accident.

 

Slightly surprised that no-one has introduced a 'grassy knoll' into this 'wise after the event' raking over the coals discussion.



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#52 Nemo1965

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Posted 22 February 2014 - 11:17

There is one aspect hinted at, in this discussion about Senna's accident, most clearly by 

 

Don't entirely disagree, but surely those two aspects are inextricably linked?

 

Is it very harsh to conclude that if a driver does not react to a bad handling car, meaning adapting his line, getting off the throttle, braking or whatever, you can say that it IS a driving error, despite the mechanical problem a car has? A driver error is: taking the wrong decision.

 

Schumacher himself said that, according to him, Senna already almost lost the car in the Tamburello the lap before. If that is true, Senna must have felt it too, he was too good a driver not to have noticed that. The pressure to finally have a good result, after the dismal early results of 1994, his own character, as Prost has said, the inner belief he had the god given right to win, made him ignore the problem with the cold tyres and the low ride-height.

 

In that light: a driver error. 


Edited by Nemo1965, 22 February 2014 - 11:18.


#53 Doug Nye

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Posted 22 February 2014 - 11:24

Indeed. And my mention of a shortfall in track inspection was merely to indicate a shortcoming in public scrutiny of a factor contributing towards a fatality - nothing more. in essence, sh-- happens... It has happened since. It will again.

One feature of the time in 1994 was that many old hands thought it would have been more appropriate to celebrate the 12 years or so through which F1 had remained fatality-free than to express such shock and amazement that it could still be mortally dangerous.

DCN

#54 Michael Ferner

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Posted 22 February 2014 - 14:12

Slightly surprised that no-one has introduced a 'grassy knoll' into this 'wise after the event' raking over the coals discussion.

 

Exactly my thoughts, especially after unthinkingly clicking the following link:

 

 

Instantly reminded me of one YouTube video which, in its own words, "proved" that JFK was shot by his own chauffeur - I kid you not!!!



#55 stuartbrs

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Posted 22 February 2014 - 14:41

Ive read that Berger tried to get the wall moved after his accident in 1987.. but behind the wall is a stream, and at the time, it just looked too hard.. a regret he obviously must always carry.

 

Freak accident.. that humans create the conditions for.



#56 Nemo1965

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Posted 22 February 2014 - 15:13

Ive read that Berger tried to get the wall moved after his accident in 1987.. but behind the wall is a stream, and at the time, it just looked too hard.. a regret he obviously must always carry.

 

Freak accident.. that humans create the conditions for.

 

It's even more freakish... Berger AND Senna visited Imola to see if the wall at Tamburello could be moved. They leaned over, saw the stream and said to each other: 'It can't be moved... there is water there.' And left it at that.



#57 kayemod

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Posted 22 February 2014 - 15:22

It's even more freakish... Berger AND Senna visited Imola to see if the wall at Tamburello could be moved. They leaned over, saw the stream and said to each other: 'It can't be moved... there is water there.' And left it at that.

 

"A stream" makes it sound too easy, behind the wall there's a drop of several feet and a good sized river that's considerably wider than the track.



#58 Ross Stonefeld

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Posted 22 February 2014 - 16:48

So why not even a tire wall? Or gravel? 

 

It'd be easy to retroactively want high-grip runoff and the SAFER barrier and other 2014 spec safety features, but Tamburello wasn't even at normal spec for the time. 



#59 Doug Nye

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Posted 22 February 2014 - 19:23

Exactly, Ross, exactly...and a contributory issue buried in the post-accident hand wringing.

DCN

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#60 Nemo1965

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Posted 22 February 2014 - 19:24

So why not even a tire wall? Or gravel? 

 

It'd be easy to retroactively want high-grip runoff and the SAFER barrier and other 2014 spec safety features, but Tamburello wasn't even at normal spec for the time. 

 

Well, if we are going to speculate: would a trap through the gravel at that speed have reduced the danger? I see an awfull barrelroll in the same situation. High grip runoff... I don't know. SAFER barrier could also have ripped off the suspension and drive it through a helmet...

 

A chicane would have changed the event, true, but I hate chicanes...


Edited by Nemo1965, 22 February 2014 - 19:25.


#61 Ross Stonefeld

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Posted 22 February 2014 - 19:51

Well it would be hard to make the accident any worse than it was. It was basically an oval crash(high speed, into concrete) with a car not designed for oval crashing.



#62 DRSdisabled

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Posted 23 February 2014 - 13:33

Why is everybody so obsessed with diffuser stall? It has its flaws and contradictions.

 

Even Newey said that if he was pushed into picking out a single most likely cause the right rear tyre failure would be it (The Guardian 2011). No mention of aerodynamics there... and he should know what he is talking about.

 

Those in favour of a mechanical failure join the likes of Ron Dennis, Alain Prost, Michelle Alboreto, writer Richard Williams, etc.



#63 Ross Stonefeld

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Posted 23 February 2014 - 14:10

Well that's an interesting group of experts.



#64 Tuboscocca

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Posted 23 February 2014 - 14:32

 

Why is everybody so obsessed with diffuser stall? It has its flaws and contradictions.

 

Even Newey said that if he was pushed into picking out a single most likely cause the right rear tyre failure would be it (The Guardian 2011). No mention of aerodynamics there... and he should know what he is talking about.

 

Those in favour of a mechanical failure join the likes of Ron Dennis, Alain Prost, Michelle Alboreto, writer Richard Williams, etc.

 

For all who didn't read it.

 

http://www.theguardi...ton-senna-death

 

Michael



#65 DRSdisabled

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Posted 23 February 2014 - 14:38

Well that's an interesting group of experts.


If Adrian Newey is not an expert on aerodynamics than who is in your opinion?

#66 Ross Stonefeld

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Posted 23 February 2014 - 14:47

I meant more RIchard Williams.

 

 

 

 

Was there no data acquisition left in the car or did the telemetry stop broadcasting pre-incident? There should be next to no doubt what happened to the car.



#67 f1steveuk

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Posted 23 February 2014 - 14:52

If Adrian Newey is not an expert on aerodynamics than who is in your opinion?

Do you know, I don't think that can be a different Adrian Newey to the one I had to speak to about all this,  as part of the official investigation. The same one that told me about the stall button on the FW15, and how they tried to continue it on the FW16, but it proved unpredictable etc etc  ;)

 

Just consider, for one second, the ride height is set in the pits, with the car stationary. Without the benefit of active suspension, the setting becomes a compremise, what may work, for as much of the lap as possible. If at any time, oh lets say when the car bottoms out, the airflow underneath is altered, and the diffuser stalls, and there is less downforce, and therefore less grip (like the days when a skirt on a "ground effect" car stuck up). Suddenly, whereas every lap before, the driver had grip, now he has none. This is why diffuser stall is a crucial component of Imola 1994, as pointed out to me, and the inquiry by a Mr A Newey. I for one wouldn't argue with him.


Edited by f1steveuk, 23 February 2014 - 15:08.


#68 f1steveuk

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Posted 23 February 2014 - 14:54

I meant more RIchard Williams.

 

 

 

 

Was there no data acquisition left in the car or did the telemetry stop broadcasting pre-incident? There should be next to no doubt what happened to the car.

There was some, but the box for the chassis was partially destroyed in the accident (not as some suggest by the Williams mechanics), and what could be extracted, was. The engine recorder (not mounted in the sidepod) was 100% in tact.



#69 JtP2

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Posted 23 February 2014 - 17:21

Steve, not arguing against your knowledge, especially in this case that you have personally investigated. But surely as soon as the diffuser stalls the down force is reduced, the car rises on the suspension and restores the ground clearance required for the diffuser not to stall. Surely goes back to F1 porpoising cars. 



#70 Ross Stonefeld

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Posted 23 February 2014 - 17:27

You're still going to lose a ton of grip and suddenly.



#71 f1steveuk

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Posted 23 February 2014 - 17:44

Steve, not arguing against your knowledge, especially in this case that you have personally investigated. But surely as soon as the diffuser stalls the down force is reduced, the car rises on the suspension and restores the ground clearance required for the diffuser not to stall. Surely goes back to F1 porpoising cars. 

As I said earlier, the deliberate stalling of the diffuser from the active FW15 was carried over in a different form to the FW16, which did not work in a predictable way. If it failed to recover it's self, the lack of downforce  would be continuous.........................................

 

I fear I have been drawn into saying far more than I should have done. The word "mystery" sucked me in, there is no mystery and I have told it like it is/was, simple facts of the matter, which I then found myself trying to defend. No one thinks Roland's accident was unusual and argues with any of those facts, why is that!!


Edited by f1steveuk, 23 February 2014 - 17:51.


#72 Macca

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Posted 23 February 2014 - 19:39

I posted this somewhere else on the tenth anniversary, after doing a lot of thinking about the causes of the  crash:

 

"After the banning of 'active' for 1994, designers tried to keep the downforce they'd had with variable ride-height, by running low but with harder springs. The cars ran nose-down to generate maximum downforce from the big flat-bottom, the rear venturis were to the maximum width and at the maximum angle before separation/stalling, the front wing endplates were of a very convoluted shape that generated vortices around the front tyres to minimise the lift effect from rolling cylinders, and the exhausts 'blew' into the diffuser so that the harder the driver's foot was on the gas, the more downforce. With very high downforce squashing the tyres down, the faster the car went the more it sucked down.

Basically they were cars that ran on a knife-edge, especially the FW14. If anything happened to disturb any part of the airflow, it might lead to a total loss of control because all the interlinked aero only worked when the car was going dead straight.

Here's the scenario: the car has been running slowly, the tyres have lost temperature and pressure and a little bit of ride-height; the car speeds up to the point where the tyres can handle the cornering force with their reduced temperature; then it speeds up a bit more, so that the increased downforce is squashing it down harder on the tyres and giving them a bit more cornering power; then it hits a bump and because of the lower ride-height grounds its skidplates hit hard; the front hits first and the nose is lifted slightly so the suction of the undertray is broken; the front of the car starts to push, and as an angle to the line of travel develops the vortices off the front endplates break away and more downforce is lost so it understeers more; the driver feels the front go light and tries to steer into the push but with little effect; he instinctively lifts off the throttle, but the diffuser is already losing effect due to the angle of slip and the increased airflow under the car as the nose lifts, so losing the blowing effect of the exhausts is the final straw; it's fallen off the knife-edge.

The front goes, then the back goes, and with much of the under body downforce lost the wings alone aren't enough to stop the car sliding straight on into the wall."
 

 

Paul M



#73 Nemo1965

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Posted 23 February 2014 - 21:01

Paul M: your story is the best, well factual, description of a feeling I always had about Williams season and 1994. Williams had a certain idea about how F1 cars work, they were very succesfull, but somehow they could not switch over to a new way of doing things. If someone would have asked me before your post, what went wrong in 1994, I would have said: 'The tried to do the same things in 1994 as they had in 92 and 93... but within a very different set of rules.'

 

I think McLaren has had that problem too the last couple of years. Red Bull, Renault, Ferrari were building much more flexible cars, McLaren kept hanging on to the the stiffer is better'-idea, it seemed...

 

 

One could say that, perhaps this season, the rulechanges FORCED them to think in new ways... and perhaps it is going to bear fruit...



#74 gold333

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Posted 24 February 2014 - 01:34

Loss of downforce through diffuser stall caused by bottoming out due to low ride height caused by cold under inflated tyres never sounded right to me.

The tires were cold enough to bottom the car out on lap 7, but warm enough to post the third fastest lap of the race (laden with considerable starting fuel) on lap 6?



Also as I recall the steering column showed stress cracks consistent with fatigue over 80% of the circumference and impact (clear breakage) over the remaining 20%. The potentiometer on the steering was reading torsion but it measured it above (i.e. Closer to the steering than at the point of breakage.) I don't know, the growing partial failure of the column could have distracted and compromised his car control on a particularly fateful split second of driving dynamics and caused him to crash.

I'm one of the few people I know who are not polarised on this topic (driver error or mech. failure) it could well have been either.

But when people like Ron Dennis, Adrian Newey, Michele Alboreto and Alain Prost are saying it was most probably mechanical failure, then thats what it is to me aswell.

#75 f1steveuk

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Posted 24 February 2014 - 11:20

I'm going to make this my last post on this subject. I am not polarised on the subject, I am not a Senna "fan", nor anti Senna, I have views on what I think happened, but they are based on good old fashioned hard evidence, that can be supported by experts and those involved, which I have shared in a way that may give an insight into the question that was first asked. There is no mystery, it was a racing accident, and you could waste the rest of your lives trying to figure it out for very little gain.

 

An accident, by definition, is a sequence of unexpected events leading to a catastrophic conclusion, which is what happened to Senna. The investigation showed, and proved what had influence on the accident and it's conclusion, and what didn't, that is one of the reasons an investigation is held. So, based on interviews I, and others did and reports not available to the public and with great difficulty within the FIA and F1 community, the following are facts!! The steering column had been stressed, but it was proven it sheared in the accident and that the modification MAY have contributed to it's failure where it did, but that the modification was done correctly, with the required drawings and up to a suitable standard. Had it not failed there, the impact was such it would have failed somewhere along the shaft. Contributing factors were also uneven tyre temperatures,altering mechanical grip, and an stall to the aerodymanics effecting the aerodynamic grip. There is the possibilty, that a mechanical fault (not failure) of the stall system may of contributed to a permanent reduction in down force. It was also stated that because of an unexpected series of alterations to the cars behavior the driver's inputs showed that he was unable to, or reacted incorrectly to bring the car under control before leaving the track, when it became impossible for any driver input to reflect in the cars behavior.

 

To summerise, it was an accident, why is it so difficult to accept the findings the investigation came to? They were as thorough with the investigation into Ratzenberger's accident, and yet no one, not one person, has questioned those findings. In Senna's case, the tyres were not hot enough, the diffuser did stall, grip was lost, and Senna either couldn't or chose the wrong way to try and correct it.



#76 gold333

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Posted 24 February 2014 - 11:50

Thanks for writing that. If I may I'd like to clear up some inconsistencies I perceived in your post.
 

So, based on interviews I, and others did and reports not available to the public and with great difficulty within the FIA and F1 community, the following are facts!!

That is very interesting. If I may, what was your assignment in the course of the investigation? As it happens I was involved aswell but from a video processing standpoint with CINECA who were the guys doing the video analysis. Were you in the taskforce or getting interviews?
 

The steering column had been stressed, but it was proven it sheared in the accident and that the modification MAY have contributed to it's failure where it did, but that the modification was done correctly, with the required drawings and up to a suitable standard. Had it not failed there, the impact was such it would have failed somewhere along the shaft.

With failure do you mean breaking? A failure is generally accepted to indicate an autonomous malfunction (e.g. Due to fatigue, stress), whereas a breakage is due to impact. I say this because I too remember the metallurgy report saying that if the 80% fatigue cracks along the circumference of the weld had not been the cause for the remaining 20% to snap at either the 2nd bump or the moment of impact, that the column would have failed at some point during that race.
 

Contributing factors were also uneven tyre temperatures,altering mechanical grip, and an stall to the aerodymanics effecting the aerodynamic grip. There is the possibilty, that a mechanical fault (not failure) of the stall system may of contributed to a permanent reduction in down force.

I wonder what you mean by this. The 16 had no stall system like the 15C had. On the 15C the left yellow button on the steering would raise the rear actively stalling the diffuser. At the same time the RS engine would enable an over-rev by 300 rpm to facilitate in overtaking on the straights. The 16 as far as I know had no such system.
 

It was also stated that because of an unexpected series of alterations to the cars behavior the driver's inputs showed that he was unable to, or reacted incorrectly to bring the car under control before leaving the track, when it became impossible for any driver input to reflect in the cars behavior.

This I had not seen before. If the writer could postulate that the driver reactions were incorrect, I wonder what the right driving reactions would have been given the circumstances?

All in all to me the diffuser stall due to bottoming out through ride height remains elusive. Personally, from my own track experience one cannot set near the fastest lap of the (entire!) race on lap 6 and then have cold enough tires to crash on lap 7.

Similarly in your conclusion you mention that Senna may have reacted wrongly to the situation. I wonder if there is enough information to conclusively enough determine what happened, what would in your opinion have been a better reaction to the situation after loss of grip? Not to have braked for example?

PS: I read you mentioned a few times that you "may have said too much", were "treading lightly", etc. If I may, what is the reason for this? I have no personal issues or qualms about divulging my involvement in the investigation to the fullest. It has been 20 years after all. I also have no one to answer to or influencing me to do otherwise. Are you perhaps still employed by the same employer, etc?

Thanks again for posting, it is nice to be able to correspond with someone on the "inside" as it were after many years of just posting back and forth between fans.


Edited by gold333, 24 February 2014 - 22:41.


#77 f1steveuk

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Posted 24 February 2014 - 12:07

I said it would be my last post, but if I didn't respond the "grassy knoll" brigade would be out in force. I, as stated in my first post, was involved due to my employment at Formula one Management, and as I said, not at the time of the accident, but later when looking into track modifications and camera positioning as well as research into various other projects within FOM, which lead to a] seeing the original interview material and b] being in a position to to conduct new interviews. Projects also gave me access to official reports and documents. Later of course, as the investigation dragged on, and fingers were pointed in FOM's direction, it became a little more important!! I am always aware that I signed contracts that were quite clear would I could and couldn't write about, and although not at FOM anymore, I don't want to "do the wrong thing"

 

Adrian said that he was "puzzled" by some of the data, and whereas I know the stall button from the active days was no longer used, Williams knew there was an advantage to gain, and a re-active method of gianing the same advantage was being tried, but he also said that he was "at odds" with some of the driver inputs, stating they weren't "normal". I would have to read into that, the the cars behavior was not "normal" and Adrian said, "maybe a tyre, but it wouldn't have been the first time he had encountered that, but maybe the rear did something new, and he was uncertain how to contain it?" This confirms what Damon had said about the FW16, that in it's early days it would be "different in each corner on each lap". As for the tyres, as I read the reports, if they were not being pushed into the ground at the "correct" down force rate, they were never have gripped, not even at the optimum temperature. Another reason I think I have said too much, I'm recalling documents and conversations from a good while ago, but the basics remain, I believe.

 

That is my last post, honest!!


Edited by f1steveuk, 24 February 2014 - 12:20.


#78 Hamish Robson

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Posted 24 February 2014 - 12:15

I'm... <intelligent well thought out and definitive respone> ...it.

 

And on that note shall we close YET ANOTHER Senna "mystery" thread?



#79 sennafan24

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Posted 24 February 2014 - 14:03

 

Thank you for all the info you posted. Been very interesting  :up:



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#80 toolish

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Posted 24 February 2014 - 16:04

Who said it was a shoddy mod'?

 

In 2011, Adrian Newey said: "There's no doubt the steering column failed and the big question was whether it failed in the accident or did it cause the accident? It had fatigue cracks and would have failed at some point. There is no question that its design was very poor." Source: http://www.theguardi...ton-senna-death.

 

Please accept that a comment like that is likely to give way to speculation.

 

Some of the theories you call 'conspiracy theories' are in fact based on evidence and/or on questions that have never been answered. If it was as clear cut as you say it is, the discussion about the accident wouldn't be going on in 2014.



#81 jcbc3

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Posted 24 February 2014 - 16:32

1) Clear cut to any sane person doesn't preclude insane/idotic/deluded/psychotic/'choose your own adjective' people to challenge the findings of a particular event. E.g. the Moon landing and 9/11.

 

2) I am in the camp that believe there is no unsolved mystery around Senna's death as explained by f1steve. 

 

3) However I applaud that inquisitive minds sometimes challenges conventional wisdom.

 

4) Even if Senna's accident was caused by other factors than I believe, it was still a racing accident with awful consequences and I know that lessons have been learned from this accident. In regard to circuit safety, in regard to steering column repairs and in regard to SC usage.



#82 f1steveuk

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Posted 24 February 2014 - 16:44

Ok, I'll rise to it just once more.

 

"It had fatigue cracks and would have failed at some point. There is no question that its design was very poor." Failed at some point, I accept the wording is provocative, but when would it have failed, next lap? Next race? Next month? It's not a smoking gun really.

 

"There is no question that its design was very poor.", Design I know nobody that designs a bodge, or produces drawings to bodge something. True Adrian was not pleased with the mod', but it was "designed", with stressing calc's, albeit a temporary fix. Bodges/shoddy mod's are usually done on the "you hold it, I'll weld it" system. That Adrian wasn't totally convinced by the tests on the break isn't surprising, and if you must quote an old newspaper article, it does say, he wasn't, at that time, certain when it broke. I believe now, he is.

 

In conclusion, I am at a loss why so many are so defensive of what they think happened, because of the regard they hold Senna in. As I have alluded to, no one question the Ratzenberger accident, that the front wing was new, untested, and might have had a manufactoring fault. No, Roland's was an accident, Senna though, there must be more to it.  Clark was considered unworldly in his abilities, yet his car suffered a failure, which he couldn't control. Why is that so much harder to accept in Senna's case? I have to say, it's only the "public"  (and I am one of them, I am just fortunate to have seen the documents and speak to the people), that can't seemingly accept what the racing World has, and acted upon it.


Edited by f1steveuk, 24 February 2014 - 16:45.


#83 sennafan24

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Posted 24 February 2014 - 17:12

Whilst I might be interpreting this wrong.

 

Would Steve's findings not actually agree with Prost, Dennis and the rest in a roundabout way. I mean if the diffuser did stall that would have been a "mechanical fault" like Prost and Dennis also believed it to be. I do know Prost said it was a mechanical fault, but did not outright say it was the steering column.

 

I know there were other factors like possibly the tyres and ride height, and even Steve seemingly left it open that Senna either was "incapable" of controlling the car or did not do so correctly.

 

My point is, what is there to be defensive about. If I have taken you out of context or misunderstood your posts Steve, please correct me.



#84 Collombin

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Posted 24 February 2014 - 17:24

Clark was considered unworldly in his abilities, yet his car suffered a failure, which he couldn't control. Why is that so much harder to accept in Senna's case?


Not sure it was to some - the Clark accident led to an 8 page thread that followed similar lines IIRC.

#85 mzustak

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Posted 24 February 2014 - 17:26

I’m the author of Tamburello. I've been made aware of this discussion thread and although I’m probably a little too late to join in, I’d still like to respond to some of the comments made:

 

1. Although I haven’t seen the steering wheel and the shaft itself, I spoke with a technical expert – who did not wish to be named in the book – who did see the wheel and the shaft and had the opportunity to examine both in detail. He confirmed there was a fatigue failure at the change of radius near the bushing (stress concentration point) where the column snapped. Two other sources (PhD in material science, expert in steering assembly) studied the available photos and considered the face of the fracture fairly typical of a part that ruptured in stages, with tensile failure in bending. If you look at the photos, the area of the initial slow crack propagation looks smooth and rubbed; the area of the final failure where the column broke off (either on impact or due to the bending force exerted by Senna’s arms) is jagged and brittled.

 

2. ‘Every metallurgist other than those from Bologna agreed it was a shear fracture’ – in addition to point 1 above, several other sources have confirmed a fatigue crack in the region of 21 to 60 percent of the circumference of the column, and Williams themselves agreed the fatigue was up to 44 percent (Autosport / Final Chapter, 1999). Adrian Reynard, who participated in the investigation as an independent observer at the request of the Senna family, was quoted by Autosport as saying the fatigue was “brought on by a downward bending force,” and that “there was a clear and well recognizable fatigue failure in the top half of the column, where it fractured. Any engineer would be able to examine it and agree.” Adrian Newey confessed to the Guardian in 2011 and the BBC in 2013 that “it [the column] had fatigue cracks and would have failed at some point. There is no question that its design was very poor.”

 

   http://www.theguardian.com/sport/2011/may/16/adrian-newey-ayrton-senna-death

 

http://www.bbc.com/sport/0/formula1/24358508

 

3. I accept that the exact position of the strain sensors is not known to me; however, I do know that no strain gauges were found on the upper end of the column that sheared. Based on the qualified opinion received from the two technical sources mentioned earlier, I can say with confidence that the three strain gauges were at the lower part of the column near or at the steering rack. It wouldn’t make much sense to install them anywhere else due to measurement accuracy. It is very easy to prove me wrong – all we need is a copy of the original design specification. It should also be emphasized that the position of the strain gauges matters only if we are concerned with demonstrating that it is still possible to record measurable strain even with the steering wheel completely disconnected. If the column broke partially, some strain would be recorded regardless of the position of the gauges (see also Final Chapter, Autosport).   

 

4.It’s incorrect to claim that I ignore the fact that the wheel had a degree of movement in it. The book clearly states that the observed range of flexing movement is between 4 -5mm (Brazil, Aida) and 6-8mm (Imola) during the 11 minutes of on-board footage I had been able to obtain and analyze (frame by frame) between the Brazilian Grand Prix 1994 and the end of lap 5 at Imola, and there is no mention of a rigidly mounted steering wheel in the book, either. The facts are that (a) the flexing got much worse in the last 60 seconds before the crash after the Piratella corner, so much so that in the last three seconds it reached 25-28mm, (b) there is no footage of Senna or Hill experiencing this amount of flexing in racing conditions except for the ‘after-the-fact’ demonstration involving David Coulthard. Furthermore, there are at least three laps showing Senna and Hill driving through Tamburello in practice and the warm-up, and the steering wheel behavior on those laps is completely different.

 

5. Regarding the plane the steering wheel should be moving in if the column partially broke: in fact, the wheel does seem to be moving in a slightly different plane as Senna threads through the final chicane and enters the start-finish straight because his ‘turning right’ movement in Traguardo is almost linear rather than circular (circular in one plane will look linear in another suitably chosen plane). Once his car is travelling in the straight line again, though, the steering column is not subject to the same bending force and the wheel gradually returns to its customary plane.

 

6. ‘The twig theory’- it is quite possible Senna actually became aware of the somewhat unusual feel in the steering towards the end of Lap 6, but chose to continue for another while. Considering all the pressure he was under to win and beat Schumacher (who was following 0.5s behind), he may have chosen to first see whether the situation remains stable or whether it deteriorates further before making what would be a rush decision to pit or slow down (he was leading the race). It is not uncommon to hear F1 drivers complaining about the steering pulling slightly left or right on the straight or the suspension giving them a strange feeling, yet they continue racing and often finish the race with the damage.

 

7. The videos of Lap 6 and 7 are extensions of the book and they are authentic overlays – put together frame by frame - of the actual TV footage from the movie Senna. Anyone with patience and the right software can replicate what I have done. For those who are still skeptical about the overlays, the composite footage with the original TV feed in the background can be provided on request. The only reason I had to go with the overlays is copyright.

 

I won’t repeat here what has already been comprehensively covered in the book. All sources of information used in the book are referenced in the bibliography, unless the source specifically asked to remain anonymous. The book doesn’t reach a firm conclusion and, ultimately, it is up to the reader to decide what weight they give to the facts and new insights presented. I have no favourite theory, and if the Occam’s razor ends up pointing to diffuser stall or tyre failure instead of steering failure, I have no problem accepting that.      

 

KR
Martin


Edited by mzustak, 24 February 2014 - 17:27.


#86 SEdward

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Posted 24 February 2014 - 20:16

I remember viewing a very good analysis of the accident on the BBC's web site a few years ago. Its conclusions seemed quite plausible to me.

 

Senna went into Tarumbello slightly off-line, too far to the right, on that fateful lap. Maybe because the tyres were not warm enough. Who knows? Because he was off-line, he drove over the resurfaced part of the track, where there was a bump.

When he drove over the bump, the car momentarily lost grip and the rear stepped out to the right.

Ayrton instinctively turned right to correct the slide.Once the car was over the bump, all the grip came back and the car did exactly what Ayrton was telling it to do. Turn right.

From then on, he simply ran out of time and ran out of road.

 

Had it not been for the part of the suspension that pierced his helmet, he may have come out of it as lightly as Berger and Piquet, who both had big ones in the same place a few years earlier.

 

Edward



#87 Ross Stonefeld

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Posted 24 February 2014 - 21:21

The suspension being out of alignment would be a much less alarming feeling than the steering about to break...



#88 gold333

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Posted 24 February 2014 - 22:31

I’m the author of Tamburello. [...]

KR
Martin

 

 

Martin,

 

First of all my sincere respect and congratulations to you on the book.

 

I saw Senna crash live in 1994 and have frequented internet forums and offered an opinion now and then since those years until today. I wrote the wiki article on Senna in the early days and wrote the current articles on FW14/14B/15/15C/16, etc. I also collaborated with the two directors responsible for the Senna movie while it was being edited. I also have knowledge of racing as (out of pure coincidence) I was involved in a crash  with many broken bones that required airlifting by helicopter in a coma, from which I thankfully fully recovered, at near enough the same age as Senna when he died.

 

I have to say that your book, and by consequence this thread has a level of technical knowledge and information that I have not witnessed in any source available on the internet from 1994 until now.

 

The level of detail you are able to go into is perplexing. I have not read it in full yet.

 

Just when it was suggested this thread is no different than any other "Senna crash" thread, you show up in it.

 

 

Some notes (admittedly subjective) I remember:

 

1. The Coulthard video where he manhandles the FW16B steering wheel to produce similar deflection as shown on the CINECA footage. The force required to deflect that much was labelled as "considerable" (and the motions in the video look like they require a good deal of effort). "Considerable force" does not correlate with how I would expect a driver to exert forces on the steering wheel while taking Tamburello in 1994. The fact that the deflection in other GP's of the wheel was far less than during the final seconds of lap 7 also are notable.

 

2. Perhaps even more subjective I have always seen (perhaps imagined) that out of the final chicane, somewhere along the straight leading upto Tamburello. (Edit: I found a video, at 3.5s into this vid).

 

 

It looks as though Senna looks down onto his steering wheel (after the first of a few bumps). Admittedly it's a subjective thing (and this thread should really try to stick to just objective "facts") it struck me because having racing experience, I know one almost never looks at the controls of the vehicle while on track. It's just instinctively a very odd thing to do.

 

But like I said I just wanted that to be out there, but it isn't something that can be objectively discussed and it is far more satisfying to stick to the facts.

 

 

3. There was an issue raised about abnormal front right toe-in in the last few frames of the trackside footage (from Villeneuve corner) looking back at Tamburello. Was this ever examined? It was suggested that that would have indicated a failed component as well.

 

 

Thanks again for your hard work.


Edited by gold333, 24 February 2014 - 22:33.


#89 Ross Stonefeld

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Posted 24 February 2014 - 22:35

I don't think he's looking down, I think that's helmet tilt from the deceleration.

 

I hate to go only by video, but does he get a bit of a slide/opposite lock momentarily? Like a split second? Because that would support bottoming/stalling/tire problems more than the steering breaking. Which would give you pretty bad understeer...



#90 gold333

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Posted 24 February 2014 - 22:56

I don't think he's looking down, I think that's helmet tilt from the deceleration.

 

 

 

3.5s into that video is on full throttle.

 

Why would there be deceleration? I'm afraid I don't understand.

 

In addition it is a smooth, controlled downward tilt as opposed to the violent "bumps" a split second before.

 

But lets not focus on it as it is impossible to prove either way and could potentially derail any objective discussion.


Edited by gold333, 24 February 2014 - 22:58.


#91 Ross Stonefeld

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Posted 24 February 2014 - 23:33

Oh I thought you meant the movement closer to 10 seconds.

 

He may be looking at the display or something. On a 1994 Williams it's sort of hidden behind the wheel. and inside the cockpit edge.



#92 Regazzoni

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Posted 25 February 2014 - 07:34

Martin,

 

First of all my sincere respect and congratulations to you on the book.

 

I have to say that your book, and by consequence this thread has a level of technical knowledge and information that I have not witnessed in any source available on the internet from 1994 until now.

 

The level of detail you are able to go into is perplexing. I have not read it in full yet.

 

Thanks again for your hard work.

+1.

 

I have read it in the weekend. Very well done, thorough, balanced and with good engineering judgement. Vivid congratulations.

 

If I may, I want just to express my admiration and respect to the "Bologna metallurgists". I come from exactly the same school.



#93 f1steveuk

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Posted 25 February 2014 - 10:33

I'm sticking with not adding any more myself. I have simply repeated what I have seen, read and heard. All I will say is I have contacted Martin directly, and said much as has been said in the thread, having written a book with a similar chapter on Donald Campbell and his accident, I know how much time and effort goes into these things.



#94 Longtimefan

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Posted 25 February 2014 - 11:18

I'm very interested in this, I was and still am a huge Senna fan and will never forget seeing that live on TV.

Does the book mention or go into detail about the telemetry data box in the car, I have read several disturbing things about it and would like to know the truth regarding this.

#95 D-Type

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Posted 25 February 2014 - 11:53

I'm very interested in this, I was and still am a huge Senna fan and will never forget seeing that live on TV.

Does the book mention or go into detail about the telemetry data box in the car, I have read several disturbing things about it and would like to know the truth regarding this.

 

Do you mean more than this?

 

There was some, but the box for the chassis was partially destroyed in the accident (not as some suggest by the Williams mechanics), and what could be extracted, was. The engine recorder (not mounted in the sidepod) was 100% intact.



#96 sinnae404

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Posted 25 February 2014 - 11:55

Thanks Martin for an excellent post.

The only thing that doesn't sit well with me in this discussion to date has been the somewhat unscientific assumptions that people are making in order to reach a conclusion that perhaps fits a desired narrative.

It's an easy thing to do - reach the conclusion then shape the facts to meet that conclusion - and I'd say we are all guilty at times.

 

Your post is to be respected because it does not do that, but merely states the facts as they are known without projecting an opinion beyond those facts.

 

I mean this as no offence to those who have posted earlier who clearly know much more than I do, but I am grateful you have chosen to 'leave it to the reader' because clearly the facts available do not support a definitive conclusion.

 

Out of interest, I'd like to know how many metallurgists examined the actual steering column and what the split of opinions was.  As there seem to be very different interpretations (according to your sources and Steve's) I can't see how this could support a conclusion either way.



#97 rachael

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Posted 25 February 2014 - 12:50

I used to work with the stress analyst who was at Williams at the time of the accident, he isn't the most reliable of characters but this is what he said;

100% the column failed before the impact and the telemetry confirmed this.
The data recorder was doctored to remove the evidence of failure.
Back at the factory there was a rear guard action to remove other similarly modified columns and prepare reports showing that it should have been acceptable.
Stress analysis of the steering column was typically done at this time as a pure couple applied at the steering wheel rim - they had little comprehension that the driver was applying axial and bending loads due to braking and cornering G loads on his body.



#98 CSquared

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Posted 25 February 2014 - 21:47

My interest in this topic is primarily around the vehicle dynamics/physics. 

 

It's never made sense to me how a bump, or cold tires, or a stalled diffuser would make the car do what it did (in addition to those theories having other problems, e.g. the tires could not possibly have been cold after doing the 3rd-fastest lap of the race, or the location of this phantom bump that didn't affect any other car on any other lap in the slightest way and could not be found afterwards, etc). Vehicle dynamics issues:

- Traction loss from a bump is both partial and temporary, unless the bump is enough to lift the wheels completely off the ground, in which case it is total, but still temporary. So why would the car stop rotating and go straight off? 

- If the diffuser stalled, causing sudden reduction in traction at the rear, wouldn't the car spin? 

- We've all seen when the steering corrections to a slide are out of phase with the slide and the car starts sliding one way, then snaps around the other (this is, I think, what Newey suggests with the flat rear tire). That is also not at all what the car did. In that case the car does not go perfectly straight. 

- In all of these cases, if he still had braking traction and steering control, why didn't he steer away from the wall during that long distance over the track and the concrete runoff where he had enough traction to brake from 190 to 135 mph?

 

I've never seen a car do anything like what this car did because of a bump or a tire issue or an aerodynamic issue. If anyone could show me video of such a thing, I would be very interested to see it.

 

On the other hand, the car did precisely, nothing more, nothing less, what you'd expect it to do if the steering column broke: the caster straightened out and the car went arrow straight while still having braking traction. Then, investigating the accident, we find out three other things: 1. The column had been modified (even if the modification wasn't shoddy, which many sources say it was, it still means this column was different than any other and different from the ones we rarely see having problems). 2. The steering wheel was moving unnaturally just before the accident. 3. The steering column was, in fact, broken. Those are quite the "coincidences." I would need evidence that was virtually bulletproof to actually accept these were all coincidences, that the accident just coincidentally resembled, in every meaningful way, a broken steering accident. We all know that that evidence is nowhere near bulletproof.



#99 Ross Stonefeld

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Posted 25 February 2014 - 22:17

 

 

I've never seen a car do anything like what this car did because of a bump or a tire issue or an aerodynamic issue. If anyone could show me video of such a thing, I would be very interested to see it.

 

 

 

 

Start watching Indycars on an oval, particularly Indianapolis or other lower-banked tracks.



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#100 funformula

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Posted 25 February 2014 - 23:13

The whole Senna incidend reminds me of the case of the moon landing or the assasination of JFK.

As usual in these cases there are plenty of "facts" which will undoubtly prove the truth of either version.

 

My subjective view regarding the onboard coverage is that the car tends to snap-oversteer for a fraction of a second while driving over a bump in the Tamburello curve. Maybe as a reaction to correct/prevent the car from spinning you can see a steering reflex to the right. Maybe its a combination of a reflection of light and poor TV quality but I there is a significant movement of the steering arm/steering rack visible according to a clockwise movement of the steering wheel. Well at least that is what I see.

Wouldn´t there be a anti clockwise movement of the steering wheel when it had been broken at that very moment?

This would indicate that the steering wasn´t broken before the impact.

In the following you can see Sennas helmet appear in the picture, while it was outside the picture going into Tamburello which indicates the G-Forces turning from right to left according to the steering direction.

It´s impossible to judge the cause of the Senna accident only by viewing the TV onboard coverage without having access to all the other relevant data but I share the opinion to let these data´s and true facts for the real experts and all the persons involved by the sad loss of Ayrton Senna.

Anyway thanks to f1steveuk for sharing a little more insight information.