Crash Analysis

[Renegadenemo]

I like this one so I thought I'd throw it out here in case anyone fancies a natter on the subject...

I'm asked all the time what caused the accident and I have to answer honestly that I can't say, it's just too big a subject. Firstly, there's the things we are yet to learn about. We know the boat had fueling problems and with her original fuel system being rebuilt to running order we may yet learn something crucial. Likewise with the electrical system. We know she suffered severe wiring damage and this may have been caused in the instant after the crash as her cockpit wiring was severed and shorted or, more sinisterly, by the addition of a second LP boost pump haphazardly wired into the loom that had to work harder and harder as the run progressed. These questions we may very well answer in the fullness of time.

Then there's the stuff that lies beyond dispute but as yet has not properly analysed. It's long been known that the forward engine mount failed sometime before the initial impact but how long before and what effect this would have had (if any) has not been scientifically explored yet. The boat also had a significant weight bias to the left (look at how she wallows after the crash) due to the placement of ancillary equipment when she was re-engined in 66, and the design of her fuel and hydraulic systems and placement of fluids within them only made matters worse.

Then there's all the speculative stuff like did Donald simply go too fast? But even that is an imprecise science where the aerodynamicists and hydrodynamicists seldom agree because it all takes place at the interface between two fluids and there's no hard and fast rules down there.

This is one of those things we could debate until the end of time so if anyone wants to pitch in feel free...

[f1steveuk]

Well for my part I can only say this;

As part of my apprenticeship I had to study crash analysis, and we were at college alongside those sent from the local police forces. The one thing that always struck me is, having been shown the end results and asked to speculate on what we thought had happened, invariably, when shown the footage, we were usually miles away from what had actually happened, such are the dynamics of an accident.

When I worked in F1, crash analysis took up a lot less of my time, but I did have extra data, such as telemetry from the cars, sometimes on board footage, sometimes the driver noted certain behaviour in the car, and sometimes we actually caught the whole thing on film, but still things would rarely match 100%!

In the writing of Leap into Legend I was lacking physical evidence, K7 being 147 feet down in Coniston, although I did have the odd verbal report of the state of the wreck from divers, so I had to do what most "witnesses" do when reporting on crashes, assume/speculate/guess the gaps to try and get a fluid timeline of events. I say this as many many times when interviewing a witness, you ask, "so what happened", and the reply comes " well I heard this noise as the car hit the wall" which actally means they didn't see the accident, the sound of it attracted their attention to it, they saw the aftermath, and their brain filled in the gaps.

With K7 there is a lot of evidence, but I still don't think we'll all agree on everything!! It is however a fascinating science.

[Mike Bull]

I'm not convinced that there's any one 'smoking gun' asides from the fact that while travelling at a fastest ever, irrecoverable speed, Donald lost his engine and it's vital down thrust. The exact cause of the engine loss may be pinned down one day or it may not, but the lack of any efflux whatsoever when she stands on her tail is an absolute certainty. It's hard evidence, and not supposition, unlike such theories as the spar fairing damage. The damage to the fairing was obliterated in the crash and any examination of it's effect must therefore be based solely on a couple of photos and maybe some film footage. You can't present a mathematical theory on something that you haven't physically examined, to measure the area of the damage, the contours of the dent, etc.

That's not to say that other factors weren't going on in there too- the dent, the weight distribution, the tail fin, the water conditions etc, but whatever factors were unsettling the boat were moot once that engine cut out. There's your cause. Now, the cause of the cause however...

[Rob Thomson]

Hello,

I read somewhere that the design of the intakes (and the shape of the panels either side of the cockpit) didn't lend themselves to working well at high angles of attack. I can't imagine much air being able to enter the intakes as the boat flipped, and therefore I'm not surprised there isn't a visible efflux regardless of the state of the engine prior to take-off. Perhaps not as conclusive as often suggested?

Also, can you tell me how the engine balances on its main mounts; i.e if you removed the front mount would it fall nose or tail first?

Cheers,

Rob (frequent visitor, infrequent poster).

[f1steveuk]

If you check the footage, the thrust has gone long before the nose came up. As for the splash shields, the duck dent etc etc, all contributing factors, as I think I have said before, there's a lot of accidents about to happen, but without ALL of the facets, at that one time, they are near misses, when everything than is needed to go wrong, at the same time DO go wrong, that's an accident.

[Richie]

If the engine was to hand it could be established if the engine was under boost / acceleration when it impacted the water it would mean a full strip down of the unit though like most devices they tend to leave specific evidence upon collisions an example would be "Did the motorcylist have his head light on" this can been checked by examination of the light filament (if its still there)

if i may offer my guess (and it is nothing more)

Donald made his first run, then for reasons unknown (most likely pressure of getting the matter over with having waited for a while due to inclement weather) he has embarked on his return run the boat light on fuel which further compacts the uneven weight distribution through his control systems etc.. he has not allowed his previous wake to settle and has pretty much gone for it ! i believe the critical angle for the boat was 3deg he has hit a wake which has lifted the sponsons beyond the critical angle, speed / inertia etc etc have done the rest.


personally i think he killed the engines when she started to tramp big style or through vibrations on the electrics... but looking at the footage i would have expected the nose to have dipped.


if you have the exact position of all the pieces of the wreck plotted i may be able to get a forensic reconstruction done (may)



one thing i did note.. and i am unsure that it should be mentioned...but Bill can delete if it is considered too sensitive.


I read online (not here by the way) that someone had somehow come to conclusions regarding injuries sustained by Donald. Without being privvy to all the facts i am interested how this conclusion had been reached as these types of conclusions tend to frustrate the hell out of me ? with these things there are a lot of theories and opinions, as Steve has mentioned most of these things are guesswork based usually on a professional opinion (speculation), some physical evidence and a mix of expertise and such... With fatal collisions it is predominantly based on physical evidence witness statements are usually less reliable as Steve stated the brain tends to fill in the gaps, or each person views things differently ie Old biddy "He was driving very very very very fast indeed" Young chap "He wasnt driving very quickly at all" two statements totally contradictory whereas a locked wheel mark or other marks and scuffs at a scene can tell a lot more.

With Bluebirds accident alas we are 34+ years too late and as we know, no marks are left on water..

[Jordangbr]

The engine is up at the Ruskin museum in Coniston. Bill states elsewhere on this forum that the engine was spooling down when it took a large gulp of water on impact. The reason is that the first stage compressor vanes aren't badly damaged which you would find if the engine was under power at the time of impact.

[f1steveuk]

Richie, I'd suggest reading the last chapter of Leap into Legend (until Neil's book is out).

DC had practised, and got away with the quick turn around/not refueling method many times, not least when setting the record in Oz. I don't have a copy to hand, but I am certain he'd used it at Consiton in '66 at least four times, once after hitting 297 on the north/south run, much like Jan 4th.

The design of K7 set out to deliberately negate any effect of low fuel weight etc, being mounted at the c of g (for the Beryl at least) and of a saddle type.

F1, guesswork!!!!???? As I said, we had MORE data, telemetry, driver reports (assuming they weren't fatal of course) marshalls reports (all instructed to face one direction during a race so someone always sees what is happenening), film footage etc etc and yet in the case of Senna, we still struggled to get a full scenario for some time, but did in the end.

[Mike Bull]

Let's take it easy regarding discussions of what physically happened to Donald, okay chaps? Ta.

[Renegadenemo]

Also, can you tell me how the engine balances on its main mounts; i.e if you removed the front mount would it fall nose or tail first?

The engine C of G is aft of its centre mounts (about which it can pivot see-saw-like) because the hot end is all steel whilst the compressor is mag-alloys. With the front mount gone the jetpipe end would drop.