Pic of the Day

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Renegadenemo
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Re: Pic of the Day

Post by Renegadenemo »

Hard to say what's what with the diameter of the fuel lines without more info on the Beryl. Perhaps it happily consumed fuel through a 3/4" dia line and gave its best - we don't know.
What we do know, however, is that everything Orph' feeds through a 1" pipe so what they've done is to make an adaptor from the 3/4" pipe in the tank to take a 1" BSP fitting even though they left the ID at 3/4".
Now considering that the pickup pipe inside the main tank is around 5' long, which is about half of the total length of fuel delivery line to the engine and that it's 3/4" ID throughout, you'd think they'd have done something about that when presented with an Orph' that clearly wanted a 1" diameter pipe to feed it yet they left a glaring piping loss in place when it would have been very simple to modify the main tank to put an inch diameter fitting somewhere low down to feed the aux tank and its boost pump.
Considering our reduced power requirements for display purposes only it may be feasible to leave well alone but as ever we'll take best advice from those who know.
I'm only a plumber from Cannock...

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conistoncollie
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Re: Pic of the Day

Post by conistoncollie »

Mike, rest assured your daily uploads and descriptions are greatly appreciated, even if I (we) don't always publicly acknowledge the effort and thought that goes into them.
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Adrian74
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Re: Pic of the Day

Post by Adrian74 »

Renegadenemo wrote:Hard to say what's what with the diameter of the fuel lines without more info on the Beryl. Perhaps it happily consumed fuel through a 3/4" dia line and gave its best - we don't know.
What we do know, however, is that everything Orph' feeds through a 1" pipe so what they've done is to make an adaptor from the 3/4" pipe in the tank to take a 1" BSP fitting even though they left the ID at 3/4".
Now considering that the pickup pipe inside the main tank is around 5' long, which is about half of the total length of fuel delivery line to the engine and that it's 3/4" ID throughout, you'd think they'd have done something about that when presented with an Orph' that clearly wanted a 1" diameter pipe to feed it yet they left a glaring piping loss in place when it would have been very simple to modify the main tank to put an inch diameter fitting somewhere low down to feed the aux tank and its boost pump.
Considering our reduced power requirements for display purposes only it may be feasible to leave well alone but as ever we'll take best advice from those who know.
Bill,

The Specific Fuel Consumption (sfc) for the Orpheus is around 1.07 lb/lb thrust/h at full chat and that is for 5,000 lb thrust. The Beryl (according to Wiki) is around the same. Based on these figures the fuel consumption for the Orpheus would be 35% more than that of the Beryl (which is around 3,700 lb thrust). That is a lot of additional fuel to suck through the same size straw! On face value it looks like a glaring oversight but we don't know how much pressure they were under to get the Orph installation ready in '66. It is certainly not something you would do on a clean sheet design.

I think the clue here is that the Orph fuel lines are standardised at 1" which would have been sized to provide sufficient fuel for all operating conditions. therefore we can say that for the Orpheus the 3/4" pipe is undersize. However if you are only looking for 2,500 lbf for display purposes it may be fine, besides the 3/4" pipe is original spec!

Ade.
Last edited by Adrian74 on Sun Dec 20, 2015 5:21 pm, edited 2 times in total.
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Renegadenemo
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Re: Pic of the Day

Post by Renegadenemo »

Hi Adrian,

The plan is to up-size the plumbing inside the tank to 1" throughout. We can do this without losing any visual originality on the outside and the old 3/4" pipe can remain inside and redundant, unseen as it always was, whilst a new one of the correct diameter takes its place. The brass adaptor at the outlet will also spin out to 1" ID without anyone being able to tell the difference and as all our mod's will be properly documented and reversible we'll not be straying from good museum practice so I think our plans for the fuel delivery are fairly well sorted - but please let us know if we've missed anything.

For those who might have missed it - Adrian knows an awful lot more about this subject than we do!

On another note - Bluebird's entire hydraulic system, which our Richie has been fighting onto a test rig for the past few months, was finally powered up and run in anger today. Well, not quite anger, mildly enthusiastic, would be a better description and you'd not believe what happened. It all worked perfectly first time straight out of the box!
Yes, we've had to stop a leak or three (dozen) and pull the rig up and down a few times but today, as a lovely Christmas present to ourselves, we rounded out the day by extending and retracting the water brake not only under hydraulic power from the pump but also using only accumulator pressure with the pump shut down. As an additional point of interest, though we've rebuilt the pump and all the various valves by hook or by crook, no one has ever so much as looked at the accumulator. It came out of the gnat, went into the boat, survived a crash followed by 34 years on the bottom of a lake and another 15 in dry storage yet the moment it was plugged back in it just picked up where it left off. Just goes to show that our engineering forbears knew their stuff with their slide-rules and log tables.
I'm only a plumber from Cannock...

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mtskull
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Re: Pic of the Day

Post by mtskull »

Renegadenemo wrote: As an additional point of interest, though we've rebuilt the pump and all the various valves by hook or by crook, no one has ever so much as looked at the accumulator. It came out of the gnat, went into the boat, survived a crash followed by 34 years on the bottom of a lake and another 15 in dry storage yet the moment it was plugged back in it just picked up where it left off. Just goes to show that our engineering forbears knew their stuff with their slide-rules and log tables.
Hmm. Not sure if it is a good idea to take the accumulator for granted. It is a pressure vessel after all and when it is charged one end will be containing gas at full system pressure; what's that, a couple of thousand psi?
Maybe a few integrity checks might be in order?
Obstacles are those frightful things you see when you take your eyes off your goals.
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Renegadenemo
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Re: Pic of the Day

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It is a pressure vessel after all and when it is charged one end will be containing gas at full system pressure; what's that, a couple of thousand psi?
Absolutely right - maybe I ought to have explained that a little better. In the Gnat the accumulator runs between 1450psi and 3000psi. Thus far we've had ours up to 1500 as we've chased out the leaks. The accumulator itself was enrobed in Coniston mud and remained tight and dry the whole time so it's in immaculate condition. It's a piston type accumulator so the big concern was that the gas would get past the seals into the oil side or vice-versa but the seals had a couple of days wallowing in fresh hyd oil and so far it doesn't leak in either direction. The gas volume is very small so no chance of a big explosion there and if the oil gets loose we'll look like we did yesterday when the selector valve (a piece of Vulcan that sends fluid to either side of the water brake piston at the flick of a switch) decided to centre its slide-valve and function properly with a happy explosion of hyd oil.
As bits of old boat go that one is relatively benign but not to be disrespected either.
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Richie
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Re: Pic of the Day

Post by Richie »

It was a good day ! In fact a great day, that system had sat sad lifeless and unused since the unfortunate day on the morning of the 4th Jan 1967 until 1700hours 19th December 2015 the unit as a whole (and as designed) powered up, came back to life, served its purpose !! Mind boggling stuff I expected a violent reaction from the ram, but was surprised to see an elegant smooth deployment, kudos to BFG for his work on the piston.

Some snagging still to do but nothing massive (in comparison to the overall job)

I left with a big Cheshire Cat smile yesterday....Bill turned having fired up the system and got the desired effect and we immediately shook hands......clearly we were on the same page at that moment :)
Last edited by Richie on Sun Dec 20, 2015 3:42 pm, edited 1 time in total.
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Re: Pic of the Day

Post by sbt »

Richie wrote:Bill turned having fired up the system and got the desired effect and we immediately shook hands......
Right, thats one scene from 'Out of the Lake', the companion piece to 'Across the Lake', sorted...
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Renegadenemo
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Re: Pic of the Day

Post by Renegadenemo »

It's been a long and painstaking build to get the whole hyd system back together, onto a rig and working and it's been Richie's baby for as long as I can remember. Many people have done bits for it here and there but when you see the big snarly mess on the bench with all its pipes spannered hither and thither it's an impressive setup and seeing the pressure come up, the joints staying tight and all the valves working to have the water brake extend and retract smoothly was a long time coming so we enjoyed a small celebration when it worked.
I'm only a plumber from Cannock...

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Adrian74
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Re: Pic of the Day

Post by Adrian74 »

Renegadenemo wrote:For those who might have missed it - Adrian knows an awful lot more about this subject than we do!
Lol, may need to eat your words there Bill, got the thrust of the Beryl wrong! Corrected now though. Still a sizeable increase in fuel flow with the Orph :-).
Adrian
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