The Bluebird Years

[Renegadenemo]

I once had a very serious scientist and arospace aerodynamicist explain his mathematical model of the accident and how it correlated perfectly with a bunch of CFD he'd had done on a supercomputer but he was unable to tell me how they'd modelled a man in a cockpit with suddenly brown underpants and what effect - mathematically, of course - this may have had on the model in different scenarios.
When you can model a stressed man in every scenario you can name your price - the divers will tell you that at the moment.

[jonwrightk7]

i reiterate my previous comment regarding mr newton. i think mr mitchell is simply following this line of thought, and all success to him.

[Renegadenemo]

Don't get me wrong, Keith is a gentleman and a scholar but sometimes, no matter how hard you try, all you're left with is an ugly heap of what-ifs and I think this is where the K7 crash investigation stalled forty years ago and it's not moved since. Perhaps it should be written off in aviation terminology as a NPD - not positively determined.

[jonwrightk7]

the only person who could give a real first hand account of what happened on 04/01/1967 is now resting in the churchyard in coniston. i feel its just human nature to endevour to find what sequence of events occured that day. donald could have thought, and probably did, after the average of the first run."sod it, lets get it done" he knew the risks but needed the record. hind sight is a wonderful thing and i feel mr mitchell is just applying hind sight to a tragic accident and is simply trying to find "what happened?"

[Drewski]

morning all

I really enjoy Keiths explanations as to the theories of what actually happened to K7.
I’m positive that everyone on the site enjoys his explanations too… so please keep them coming….. it not only makes interesting reading but also promotes positive discussion, which is what a Forum is all about !

Fortune favours the brave !

[thewrightstuff]

Hope nobody has taken me wrong- I'm certainly not against research etc into the accident, or into anything really, but I just feel in the case of K7 that there are too many unknowns to ever allow a definitive answer. Happy to be proved wrong, of course!

I am with Mike on this. However much data you analyse in connection with K7 crash you will never come up with a definitive “this was the cause of the crash”. All you will end up with as a long list of possible factors that contributed to the crash. But if that’s your predilection so be it. Me I can’t see the point of it, that’s my choice each to their own.

[Renegadenemo]

Well if we're still looking for answers I've always been faintly surprised that the failed engine tie-rod hasn't been properly investigated. It's a simple failure that can account for the accident in one go. Then there's the gyroscopics. Donald, by his own admission, passed 'close to Peel Island' so at some point he had to make a right-hand turn to get back on track, which would pick the left sponson out of the water and that's exactly what happened.
I also have an awful feeling that we're going to find something sinister in the fuel system once the engine-driven pump and fuel control unit is stripped.

[CHWk7]

Bill,
With reference to the transcripts of both runs on the 04/01/67 I sent you I can't help but feel that engine cut out problem seemed to occur when Donald backed off the throttle at high speed. This could well be a combination of fuel flow plus airflow bucketing as warned by BS. At the speeds you are aiming for for your trial runs this possible might cause you any problems. Just an opinon

[KW Mitchell]

--------Then there's the gyroscopics. Donald, by his own admission, passed 'close to Peel Island' so at some point he had to make a right-hand turn to get back on track, which would pick the left sponson out of the water and that's exactly what happened.--------

Sorry, Bill, have to correct you - it was the right sponson which was lifted.

If gyroscopic precession was contributory, the clockwise rotating Orpheus and a turn to the right would create a lifting force on that sponson; browsers might want to look at my previous posting on this matter:
http://www.bluebirdproject.com/message/ ... opics#p382

Understanding the principle is relatively easy, calculating the magnitude of the moment is not as one would have to do some very complex mathematics on the rotating masses in the bowels of the Orpheus, their angular velocity (which is related to RPM) and the radius of the arc BB was describing - plus the crafts velocity. Not easy!

Of course, if the correction was completed at the start of the measured km and DC was maintaining a straight track thereafter - or even in those few fateful moments when that sponson began to rise (not unreasonable I would have thought) - the conditions for gyroscopic precession and its resultant lifting force would be eliminated .

More believable in my view is to examine what was happening to the airflow around that dished port front-spar - and I have calculated significant forces and moments due to the aerodynamic drag on that member and the asymmetrical airflow therefore arising over both the spars which would tend to lift the starboard sponson, see:

http://www.bluebirdproject.com/message/ ... tries#p358
http://www.bluebirdproject.com/message/ ... tries#p372

That damaged front spar had to produce a left yaw which DC could only control i.e. maintain track, by applying corrective right rudder. We know from the newsreel&video evidence that as BB became airborne there is a yaw to the left which develops into the off-track somersault to the left. In my view, this is due in no small part to the corrective right rudder being applied by DC becoming ineffective as the blade leaves the water.

And then there's the Orpheus installation, the BS report and what was happening at those intakes ----?
And what was recommended to be done, but wasn't --------------!
And there's more e.g. the effect of not repeating the wind tunnel measurements on a model of the 1966 version at scale 300mph plus?
Plus the term 'bucketting' a much misunderstood phenomenon -------------!

But that's for another time when I've analysed the full BS report, courtesy of Steve Holter.

Still think there's nothing to investigate? Not me, I'll tell you!

[Renegadenemo]

Oops - wrong sponson. That's what I get for posting after enjoying the little-un's birthday party...