Technical Talk

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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Fri Jul 31, 2015 4:35 pm

They need have looked no further than the half a ton of extra gubbins bolted into the left side of the boat in the re-engining exercise for their steering troubles and a right steering input would cause the front to lift due to gyrosocipic precession so it's no great surprise it took off, especially without engine thrust.
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f1steveuk
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Re: Technical Talk

Post by f1steveuk » Sat Aug 01, 2015 11:36 am

I think both Ken and Leo said any effect created by the bird strike would have been "negligable". Ken did once mention the possibilty of a torque reaction with the rotation of the engine effected the steering, but I'm sure the Orph' and the Beryl span the same way, and I can't think there would have been a huge increase in this effect?
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sheppane
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Re: Technical Talk

Post by sheppane » Sat Aug 01, 2015 7:47 pm

Mike Bull wrote:
f1steveuk wrote:I think both Ken and Leo said any effect created by the bird strike would have been "negligible".
Personally, I think there's been a bit of reverse engineering of theories to make them fit with the photo of the dented spar fairing, and far too much made of the whole thing.
Its all in the book.

I'll say only one thing on this Prof John Stollery, of Imperial College who was aerodynamics consultant to the Campbell team thought the drag effect would have been significant, but he did not see the images of the crash until after the event, so could not advise the team to make good the damage.
It was DC'S decision to run K7 with the damage un-prepared.
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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Sat Aug 01, 2015 8:50 pm

Prof John Stollery, of Imperial College who was aerodynamics consultant to the Campbell team thought the drag effect would have been significant
Yet I showed the pic's to a couple of aerodynamicists at AAIB some years back and they thought otherwise. It's all a little subjective so in the absence of some sort of scientific investigation we're never going to know.
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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Thu Aug 06, 2015 11:21 am

We finally worked a modified Vulcan rapid-start system up to its full delivery pressure last night. It's the same as Bluebird's system in terms of performance and shares many components. And what it revealed is that the boat's onboard start system was good for two starts and then it was all out of ideas. The gas consumption is colossal!
So, with one cold start on a January morning then a relight towards the end of the first run there's no way he could have stopped because if he'd shut the engine down there was no way to restart it.
I'm only a plumber from Cannock...

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mtskull
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Re: Technical Talk

Post by mtskull » Thu Aug 06, 2015 2:11 pm

Renegadenemo wrote:We finally worked a modified Vulcan rapid-start system up to its full delivery pressure last night. It's the same as Bluebird's system in terms of performance and shares many components. And what it revealed is that the boat's onboard start system was good for two starts and then it was all out of ideas. The gas consumption is colossal!
So, with one cold start on a January morning then a relight towards the end of the first run there's no way he could have stopped because if he'd shut the engine down there was no way to restart it.
It would be daft to deny that DC's decision making may have been influenced by the knowledge of the consequences of a failed start following a shutdown at the far end of the lake but is there any evidence, or is it just speculation that he made use of the start system at the end of the first run?
OK, it is accepted that the engine did flame out and was relit but provided that it had not slowed below idle rpm and the condition which had caused the flame out had been alleviated, then the relight may well have been achieved by the igniters, without use of the starter.
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Re: Technical Talk

Post by Renegadenemo » Fri Aug 07, 2015 1:35 am

Well he certainly did lots of shouting about how he was relighting the engine and considering that anecdotal evidence suggests the igniters being left on and that the pure turbojet Orph' spools down very quickly without a fire going on it seems likely that he hit the air-start button in all the excitement.
But perhaps not.
We're still to learn what effect the fuel, lube and hyd pumps have on gas consumption when starting a freezing cold engine but it's not looking good. Could be that once you factor in the extra energy needed to move cold oil and fuel the margin closes even further - but either way you'll get the truth, warts and all.

And to think that the museum types told us that by dismantling the boat we'd be destroying history!
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quicksilver-wsr
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Re: Technical Talk

Post by quicksilver-wsr » Fri Aug 07, 2015 7:40 am

Renegadenemo wrote:And to think that the museum types told us that by dismantling the boat we'd be destroying history!
Good point, Bill.

This is Time Team stuff - make no mistake.

What's more, "new history" is being made by restoring and running the boat, alongside the "proper history" being unearthed from the past.

Nigel

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Re: Technical Talk

Post by conistoncollie » Fri Aug 07, 2015 5:42 pm

Renegadenemo wrote:And to think that the museum types told us that by dismantling the boat we'd be destroying history!
...and fabric, don't forget the historic fabric.
Some might argue that removing a layer of dust from an object can be regarded as destroying its history.
Some of K7's history was destroyed when she was overhauled at Norris Bros in early 1966, and repairs to the intakes and spray baffles destroyed a little bit more history.
At what point in time do you preserve/conserve/restore an object? And who decides what that point in time should be? Lots of ethical issues there for academic types to ponder.

The accident was a point in K7's history, just as the sinking in USA, or the records at Ullswater and Lake Dumbleyung. What is happening to K7 now is a new phase in her ongoing history, it strikes me more care is being taken over recording and appreciating her history than at any time in her previous career.

Looking forward to the article in Practical Classics - September issue.

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Re: Technical Talk

Post by quicksilver-wsr » Fri Aug 07, 2015 6:15 pm

The problem, fundamentally, has been that the accident on the 4th of January 1967 was - for a very long period of time - perceived to be the end of K7 ... and quite understandably so.

But the fact now is that it wasn't.

Nigel

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