Technical Talk

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Renegadenemo
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Re: Pic of the Day

Post by Renegadenemo » Wed Nov 25, 2009 5:04 pm

It's the rotor band at the base of the rotor that's been water stained as has the port insert but I've been investigating today and it seems the band is heat shrunk onto the end of the rotor as a blank then machined to suit the carbon bearing. It's the band that's stuck and now I know why. There's no way on this earth it's coming off except in a lathe and we'll have to make a new one.
The stained port insert is trouble too because we need a good face to face seal to maintain fuel pressure and the way we're on at present that isn't going to happen. Good news is though that re-grinding the lower face of the rotor where the ports emerge, and the upper face of the port insert is permissable to mend matters but everything must be kept absolutely square and parallel in the machining process because only half a thou' out and you lose pump pressure. The slight increase in endfloat that would result from this fix can be adjusted out via the camplate. Don't have the material spec on the rotor band as yet but I'll get it. As for the carbon face seal on the pump extension we met those on the boost pumps and they were contrary there too. I fixed those by coating them with T-Cut and spinning them slowly for half an hour. Not a recognised repair scheme, I'm sure, but it worked a treat.
Lots of vibro-etched scribbles on the rotor but... you guessed it, nothing beginning LS.

By the way - I've also confirmed today that this is an extremely early fuel system. The CCU is only number 48!
I'm only a plumber from Cannock...

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Renegadenemo
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Re: Pic of the Day

Post by Renegadenemo » Tue Dec 01, 2009 2:16 am

Mike, we need a separate thread for this techie engine stuff.

In the meantime, it transpires that Bluebird was posessed of a prototype gadget in her fuel control system. Later Orpheus evolutions included a thing called a PRL or pressure ratio limiter that prevented the engine from burping when throttle was applied but early in Orph' development this problem was tackled with an experimantal widget designated ASC or anti-surge control. So far as we can determine only two of these were ever built to a standard derived from a 1957 lab report by Lucas Aerospace and delivered to Bristol engines early in the Orpheus development programme. And guess what... we have one of them. How cool is that?
I'm only a plumber from Cannock...

"As to reward, my profession is its own reward;" Sherlock Holmes.

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klingon
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Re: Technical Talk

Post by klingon » Tue Dec 01, 2009 12:41 pm

Just checking an old weight list for K7 and of all things theres a weight of 128 lbs for "ping-pong balls and cases"-eh?, although I seem to remember a lot of things floating on Coniston after the crash-wonder what the purpose of these was?
Or indeed if they were ever included in the boat. :?
"I hate two faced people-don't know which face to punch first!"

ace_chris
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Re: Technical Talk

Post by ace_chris » Tue Dec 01, 2009 5:23 pm

I believe the ping-pong balls were fitted as a request from Donald following his years spent as an international table tennis champion... :lol: Thought they wre fitted way back (when K7 was originally constructed?) as a bouyancy aid? Chris

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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Tue Dec 01, 2009 7:37 pm

Someone must've done away with the ping pong balls by the time we got there. We didn't find a single one. Lots of polythene flotation bags (useless for lots of reasons) but no ping pong balls.
I'm only a plumber from Cannock...

"As to reward, my profession is its own reward;" Sherlock Holmes.

'Sometimes you gotta be an S.O.B if you wanna make a dream reality' Mark Knopfler

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sheppane
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Re: Technical Talk

Post by sheppane » Tue Dec 01, 2009 9:55 pm

To the best of my knowledge, K7 was never equipped with ping pong balls. I believe K4 was, in 1939, but I'm not sure they were in the post war refitted version. K7 made do with the bags which were in the main hull, and in the sponsons...

N
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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Wed Dec 02, 2009 12:53 am

Ping pong balls would have been a far better flotation aid becaue they'd not crush at depth and at least try to keep their subject on the surface but the problem with stuffing anything like that into K7 is that there was insufficient room for any of it to be of real use.
In actual fact the hull was littered with sealed polythene bags that crush flat if you hold them only half a metre under the surface. They'd have been better binned as all they offered was an unneccesary fire risk.
I'm only a plumber from Cannock...

"As to reward, my profession is its own reward;" Sherlock Holmes.

'Sometimes you gotta be an S.O.B if you wanna make a dream reality' Mark Knopfler

KW Mitchell
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Re: Technical Talk

Post by KW Mitchell » Wed Dec 02, 2009 9:11 pm

Herewith a couple of references I've dug up:

The Man Behind The Mask (Tremayne) P. 118 - refers to a conversation between DMC and Bill Coley:-

' The first real deal I did with Donald was to sell him four thousand ping-pong balls for Bluebird K4, for buoyancy.'

Leap Into Legend (Holter) P.145 - describing the immediate aftermath at the scene of the crash:-

' The (water) surface was covered in ping-pong balls and the plastic flotation foam from inside the sponson covers.'

There seems to be some currency in the notion that ping-pong balls were regarded by the Campbells as legitimate enhancers to buoyancy ---------.

jonwrightk7
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Re: Technical Talk

Post by jonwrightk7 » Thu Dec 03, 2009 8:47 am

im sure ive seen the area of the crash, immediatly after K7 sank, with what could well be ping pong balls or something similar floating on the surface. think it could be towards the end of " days that shook the world" :)
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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Fri Dec 11, 2009 12:39 am

Great meeting at Aero Engine Controls in Birmingham today. They're a JV between Rolls-Royce and Goodrich Corp. Can't let too much go but suffice to say those boys and girls know a thing or two about our fuel control widgets!
I'm only a plumber from Cannock...

"As to reward, my profession is its own reward;" Sherlock Holmes.

'Sometimes you gotta be an S.O.B if you wanna make a dream reality' Mark Knopfler

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