Technical Talk

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kneeslider
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Re: Technical Talk

Post by kneeslider » Mon Mar 07, 2011 2:30 am

Renegadenemo wrote:
What you can't see from the photos is that at the back of the engine is a complete set of 1/5th scale working instruments along with lube oil tanks, electrics and coolant rad's. Nor can you see by looking that the magnetos each contain coils wound from the earpieces of mobile phones using wire 0.001" in diameter and that they can deliver 48 sparks on each revolution to Barry's 1/5th scale spark plugs down those stainless braided cables. It's absolutely mind boggling, it really is.
Did you take any pictures? I would love to see the instruments. My dad is a proper instrument engineer, with a background in the Nuclear industry, I bet he would love to see those too. As you say, the skill is properly mind boggling, the same sort of level as required when scratch building a watch. How many folk on the planet can do that?

Ill have to start subscribing to Model Engineer again. The trouble is that I have enough on my plate with keeping on top of a Ducati, a Laverda, a Triumph TR6, as well as my PPL ticket.

From looking at the latest POTDs, you aren't doing too bad for a Fitter Bill! :p

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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Mon Mar 07, 2011 9:48 am

I only took a few with my phone, I was very aware that I was taking up Barry's weekend, and I didn't include the instruments. I'll ask next time. Forgot to mention too that the Coffman starter on the Eagle engine is chambered for .22 rifle rounds...
From looking at the latest POTDs, you aren't doing too bad for a Fitter Bill! :p
Very kind of you to say so, but don't forget that the machine has been built by volunteers none of whom had ever worked with metal before. Not bad going, eh.
I'm only a plumber from Cannock...

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Stuart Baker
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Re: Technical Talk

Post by Stuart Baker » Wed Mar 09, 2011 11:19 pm

Just been reading some old posts on this thread (as I don't get time to visit very often).

Answers to a couple of questions:

1. Why do British Aerospace manufacturers keep drawings from 40 years ago? Because people keep ordering spare parts. The oldest part that I know of in our fuel controls business was first drawn in 1926 and inherited from another company in the Lucas group (Whittle didn't run his first gas turbine until 1937). If it ain't broke, don't fix it... The SEPECAT Jaguar first flew in 1968, the Indian Air Force still flies them today and they have a planned retirement date of 2070. It's sometimes quite a challenge reading old drawings and specs for machined parts, but when you start trying to buy parts for 30 year old electronics things get really interesting...

2. Will the Orpheus run on peanut butter? Probably if you tried hard enough, but if it had one, this would invalidate the warranty. The Orpheus pump features both silver and cadmium plated bearing surfaces which were considered pretty special in their day - the fuels also contained icing inhibitors, corrosion inhibitors, and lubricity additives. Jet A1 doesn't have that stuff in. Try and pump water with the pump and you will shear the drive-shaft (this is intentional by design to prevent more serious damage to the gearbox when the pump seizes). How many of you would restore a classic car and then buy fuel for it from the local chip shop? Give the old girl what she deserves and then inhibit the system when she won't be used for 14 days or more!

Stuart

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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Fri Mar 11, 2011 9:42 pm

1. Why do British Aerospace manufacturers keep drawings from 40 years ago? Because people keep ordering spare parts.
That's fair enough and perfectly understandable but what's positively amazing is when yours truly rolls up with what looks like a completely knackered pile of gubbins salvaged from the bottom of a lake and a giant of the Aerospace industry proves both powerful and flexible enough to wield its might in support of little people like us.
People often bemoan the demise of British engineering, but they're wrong and I tell them in no uncertain terms that it's far from dead, it's alive and kicking, you just have to know where to look...

There's a kind of tongue in cheek acknowledgement from our partners in this that they'll take their rightful share of the glory if/when all this works or, presumably, disappear into the long grass if it explodes and sinks. So for now I shan't name names but I'll tell you something - when I finally write down what Stuart and his colleagues have done for this project you'll realise too that British engineering is as healthy as ever and that the right people can still be found at the helm.
I'm only a plumber from Cannock...

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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Thu Apr 14, 2011 12:46 am

Just for those of an anoracky disposition, we assembled and charged K7's air start system tonight - the first time it's been pressurised in over forty years. We only took it to 100psi, mind you, and all the air came back out again uninvited, but it's very early days and we did seal most of the joints and get the non-return valve and filter flowing happily as well as both over-pressure valves.
The big leak was past the seat of the main start valve and seeing as both the piston seat and the seat within the valve body have been faced off in the machine shop it's no surprise that they're not airtight yet. Some gentle lapping tomorrow ought to get them snuggled up and then we'll voyage onwards towards 150psi.
I'm only a plumber from Cannock...

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Piston Broke
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Re: Technical Talk

Post by Piston Broke » Thu Apr 14, 2011 6:09 pm

Renegadenemo wrote:Just for those of an anoracky disposition, we assembled and charged K7's air start system tonight - the first time it's been pressurised in over forty years. We only took it to 100psi, mind you, and all the air came back out again uninvited, but it's very early days and we did seal most of the joints and get the non-return valve and filter flowing happily as well as both over-pressure valves.
19th March 2001 Alain takes out bung in air start system
13th April 2011 Alain put same bung back in

This is to much like hard work

The bung was nicknamed the runaway bung because when I loosened it off in 2001it started to hiss and we all ranaway until it stopped
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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Thu Apr 14, 2011 10:25 pm

Even better result tonight... We successfully operated the main start valve! It's basically a balanced piston with a solenoid operated piggyback valve that vents the chamber behind the piston to atmosphere causing it to fly backwards off the seat and dump the stored air into a pressure regulating valve. The PRV was removed for this test as it'll be tested separately but the start valve performed flawlessly at only 100psi when triggered with a piggyback valve from a Vulcan. We'll up the pressure next and try to get the original piggyback valve working. So far so good.
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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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Wed Apr 20, 2011 10:33 pm

Had a bit of a struggle getting the valve to work properly over the past few days but we cracked the problem earlier and the system was filmed by Sky firing at 500psi tonight. Only another 1500psi to go...
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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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Thu Apr 21, 2011 11:09 am

What fun to see a gloved finger jab down onto a big black button and hear the roar of high pressure air that will soon be spinning up an Orpheus!
Scared the crap out of me first time! Only the valve was fitted, the PRV wasn't attached, and I can safely say that 500psi getting out of an inch diameter pipe is brown underpants stuff!
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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Renegadenemo
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Re: Technical Talk

Post by Renegadenemo » Tue May 03, 2011 9:34 pm

The start system is working a treat now and I'm busy machining up a test nozzle so we can sort the PRV. We have a (kindly loaned) high speed pressure transducer and data logger incoming to record exactly what the valve is doing so that ought to allow us to set it up perfectly and understand it too.

Perhaps more importantly though, I had a meeting today with the company that's going to construct our new sponsons for us. The 'go' button has been pushed on the sponson build.
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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