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March 2012

The car park was full of cops when I arrived. I threw my backpack over my shoulder, grabbed my laptop and slammed the boot. The hotel reception was no different, it buzzed with excitement and police radios. Clearly something big was occurring yet there was nothing to see. One of the staff had written down a car number, an officer took it and ran past guests vying to tell of the stranger they’d glimpsed fleeing the scene. But no bloodied corpses nor bullet holes stitching the modern glass frontage were evident and yet there was certainly hell to pay over something.

“What’s happening here?” I asked, having confirmed my booking. The girl tried a nonplussed look in keeping with company policy. For professional purposes the riot squad in the hallway didn’t exist.

“You have wall to wall fitted cops…” I explained, stepping out of her line of sight in case she hadn’t noticed them.

“Oh, those.”

I waited patiently, not quite weighing over the credit card.

“There was a man,” she began hesitantly. “Outside the swimming pool looking through the glass with his phone, taking pictures, and a kiddies swimming lesson was going on, and he ran away.”

It all sounded rather sinister and now I could see why the cops were charging about despite there being no blood to slip in. It was only later in the evening that I discovered I’d actually witnessed the final straw in what was probably the worst day of some poor sod’s life.

You see, as the drama was buzzing around me, I’d heard a girl from the leisure club complaining that such events always happened on her shift and remember wondering at the time whether the bloke with the camera actually had a thing for cute blondes. Then, later on, she appeared behind the bar and as I was in need of a fresh pint I captured her and asked whether the child-raping paedophile had been caught and emasculated with a rusty hacksaw blade yet.

“It wasn’t how it seemed,” she said.

Well it never is, is it…

What really happened, it transpired, was that the poor bugger had reason to suppose that his girlfriend was sneaking about the hotel with another man. Now anyone with any sense would assume the missus and her new hero would enjoy a quick rumble in the bedroom followed by a post-coital sup of pinot in the bar so what you’d do is stick a baseball cap on your head, order a beer then sit by the door but not in full view so as to retain the element of surprise when they walked in – not peer through the swimming pool windows twiddling with your iPhone.

Anyway, that seems to be what he did so next thing is the cops have nabbed him and, for a moment at least, he’s right up there with Garry Glitter until, having suffered the indignity of having his phone thoroughly inspected inside and out, he was sent on his way with no more than a stern ticking off.

Now just how miserable would you feel later on picking at your takeaway with a fork knowing just what a crap day you’d had – especially if the girlfriend rocked up with an equally innocent explanation for why she’d been off the radar all afternoon? I had to howl with laughter yet ache with sorrow for the hapless individual.

It reminded me of the desperately unfortunate museologist who told me how K7’s accident was a snapshot in time witnessed by countless thousands and rebuilding it would destroy history – and the next day Cutty Sark burned to a crisp. Or that terminally stupid HLF officer who told me I couldn’t sack him unilaterally because I had to go consult all the other people who wanted to sack him too. I mean, who in their right mind would want to be sacked twice? It seems he did.

But that was then and this is now. So far as I know they’ve all moved into obscurity or been locked in secure units and I think we wrung as much beneficial change out of them as we were going to get some time ago so that’s that. The museologists seem to like us a little better these days and some of them are actually pretty cool but the HL-effers, pah!

And then a peculiar thing happened – I was invited to attend a HLF bash and hand out certificates to students who’d completed a course of some sort.

Who, me? The Yasser Arafat of the museum world…

In fact these days my chickens are growing fat from pecking over the patch in the garden where the hatchets are buried.

So with all this goodwill settling like snow and K7 being riveted back together at a rate of knots previously unseen, morale is at an all time high. We said a long time ago that one day everyone would be on the rivets and so it’s come to pass. What’s truly inspirational about our crew is that when it’s time to learn a new skill everyone simply picks up a new tool and cracks on to the usual standard without fuss or drama.

Something that happens often during all this assembly work is that you find yourself wrong way up in a confined space staring at a rivet wondering just how they managed to set it back in the fifties. It’s like crossing paths with the past and, having been working on the systems for a while now, there’s a question someone absolutely must have asked when faced with the new Orpheus.

“How are we going to start the damn thing?”

Those concerned with re-engining Bluebird for the 66 attempt had to contend with spannering a new lump into the space formerly occupied by the venerable Beryl but getting that going wasn’t a problem because it came with an electric starter and rowing alongside with a few batteries in the bilges and a set of jump leads was easy. But the Orph’ came with an air turbine starter that needed a great blast of air from a ground starting trolley and sticking one of those in a rowing boat was a different matter altogether. What to do?

As it happened there was one Orph’ powered machine with a self-contained air start system around at the same time, the Hunting 126 experimental aircraft. It used thrust ducted from the engine to blow high speed gas over the tops of the control surfaces giving it an extremely short takeoff run and exceptional low speed flight characteristics but this draining of thrust gave it poor performance when it was supposed to be going fast so it was not a great success generally to the extent that a second planned aircraft was never built so guess what… that left a spare set of start equipment on the shelf.

The kit was made by Lucas Rotax and in March 1966 the spare set was ‘borrowed’ by a certain Mr Campbell and never given back. Thirty-four years later we pulled the top off his dripping boat to get a look at what was left.

Not very good, is it. All that time at the bottom of the lake had completely knackered it.

(Pic by kind permission, W. Vanryn)

The entire start system hangs from the frame carrying those two spherical air flasks. It’s an elegant setup with so few moving parts you can count them on one hand, total self-containment and light enough that you can pick it up with the other, but there’s also a shocking amount of energy stored in those bottles that must be released in a controlled sort of way if you’re to avoid death or serious injury.

Fair enough, we were told that the fuel system might cause a small explosion, but at least we’d have a chance of running away, jumping in the lake or otherwise avoiding the imminent fireball if that lot went up but if a HP bottle exploded in your face it would be lights out without warning so we had to consider very carefully just what to do with such a badly corroded (to all appearances at least) bomb. Conserve or conserveer?

First thing’s first – take it apart to see what we were working with.

All the essentials are attached to the right-hand bottle by simply screwing them one onto the other like some weird, kid’s construction set but mending that lot was secondary to having somewhere to store the air in the first place so the bottles came under scrutiny first.

Outwardly they were in excellent condition and internal inspection with a boroscope revealed that the right-hand one was good inside too with no water ingress and only a light dusting of surface rust but the outside had pitted here and there. We sought the advice of a specialist who told us that carrying out hot work on the bottle was permissible so long as we used the correct TIG rods. The ones selected are for making welds on high pressure gas pipes so we had the bottle blasted, ground out the pits and filled them.

With that done we polished the surface.

And that was that bottle good to go – to the untrained eye at least – but that’s not the issue when dealing with HP air. Honestly, it’s lethal stuff so we took the repaired bottle to the local testing facility and had it blown to 3200psi, it’s old working pressure, not with air but with water.

Water is incompressible for our purposes so if the bottle fails you only get mildly splashed not blasted with shrapnel but the gauge stayed there quite happily for half the afternoon without losing any pressure or weeping a drop. We then imposed a new, max working pressure of 2000psi, which is more than enough for our purposes, then we went for a look at the other bottle.

It wasn’t good. The right-hand bottle carried the start equipment and the various valves did an excellent job of keeping it dry inside but the left was only for storage and the corroded fittings had let the lake in. Only to a depth of an inch or so but it was enough. The pitting on the outside was much deeper too so we did the only sensible thing and cut the bottle in half. It sounds drastic but it was made in two halves to begin with then welded together so all we did was take the weld off to reduce it to its component parts.

The damage didn’t cut deeply into the metal but it gave the inside surface a pitted finish and cracks like to grow from any sort of irregular surface. We ground the metal back a millimetre or so in one-inch squares then built it up again and polished the interior. It took an absolute age!

Every last blemish was ground out, repaired then polished inside and out and that is bloody hard steel!

Then the bottle was given a 45 degree weld-prep around both halves, tacked together and purged with pure argon before being welded in three, non-stop passes to put the root of the weld in, then to fill the weld-prep level with the outside of the bottle and finally to cap over the top for maximum strength.

That amounted to twelve feet of continuous weld and once complete the second bottle easily sailed through its hydraulic test and is arguably now the better of the two. So now we had reliable air storage – so far so good – next we needed something to hang it all from. At least that was easy because the frame that mounts the start system is a straightforward lump of fabricated steel with no moving parts or the possibility of exploding, melting, running away with itself or any of the other undesirable things that many of the parts dealt with recently may like to do. It wasn’t in the first flush off youth, however.

Cockney Chris soon had it fettled, though, with some patches and welding and grinding while the rest of the crew did some equally clever metal grafting with the spiders that hold the bottles to the frame. Being thin steel they didn’t come out of the whole crash, sink, fizz for thirty-odd years, thing very well.

But they fixed up nicely and we even saved the original rubber that protected the steel clamps from the steel bottle.

Believe it or not, the above is mostly original. As is this little lot.

That’s the bulk of the start system back together and it’s all the little awkward bits from here. The devil is in the detail, as they say, especially when you want the detail to safely handle HP air.

First of the downstream widgets is an air valve that basically opens the right-hand bottle to the outside world at the push of a button while the two bottles are equalised by a hose that runs under the engine inlet trunk.

The main valve has what’s known as a balanced piston inside. The piston has tank pressure either side of a seal midway along its length so there’s no tendency for the air pressure to push it one way or the other, then there’s a spring to hold it closed against a seat so no air can escape to the outside. But suddenly release the pressure from the back half of the piston and now you have tank pressure at the front versus only the spring at the back so the spring loses and the piston flies backwards allowing the air a bid for freedom. The nose of the piston is shaped such that aerodynamic forces keep it held firmly out of the way once the compressed air starts to move.

Restore tank pressure behind the piston and now the piston is balanced again leaving the spring in charge so the valve slams shut. As with the fuel pump, a simple concept that now only has to be made to work safely and reliably. Uh-huh… easy, is this conserveering.

The valve was very sorry for itself with extensive corrosion due to it being in the proximity of so many different metals and, indeed, being made of so many different metals itself. There was some hope, however because the upstream end of the piston was immaculate as it had kept the water out of the bottle all that time so maybe the rest of it had survived.

Unfortunately it took a hydraulic press to get it out and that says it all – shame.

Once stripped, the valve body was thoroughly blasted to see exactly what was left – not a lot, as it happened.

But notice that some of it has already been repaired because it welded nicely. Sometimes it was necessary to chase the corrosion down the grain of the metal. It shows in the weld pool as a black spot so what you do is stop and dig it out with a die-grinder then arc-up again until the spot reappears, or not, and you continue this process until nothing but a glistening pool of liquid aluminium appears at the bottom – then you fill it up again.

First it was given a lot of reconstructive surgery followed by as many hours of cosmetic work.

From there it went to the workshops of Algernon Precision Engineering here on Tyneside to have its guts made to work again. The piston was dead and the bore was corroded too so it was taken 0.5mm oversize and a new piston machined to suit.

Old piston top, new one beneath with both laid on the drawing so you can see where it goes. That got the bulk of the main valve back into operation because the spring was immaculate and was reused – what next?

Remember how the balanced piston thing worked, with air released from behind the o-ring seal that you can see halfway along the piston? That’s done by what was referred to back in the day as a ‘piggyback valve’.

Here it is and note the part number. M4901 EXP.1

This, I am told, refers to an experimental part so it was certainly worth trying to bring it back to life in the interests of originality. It works by means of a solenoid, beneath that black cap gripped by fingertips at the left, that pushes a stainless steel shuttle a tiny distance measured in thousandths of an inch to unseat one valve and firmly seat another. The shuttle has sealing faces along its length and when at rest it allows tank pressure to pass straight through to balance the pressure either side of the main piston. But push the start button and the shuttle closes off the space forward of the piston and vents the aft space to atmosphere. It’s a really close-tolerance part that we were told we’d never get going again.

Its internals seemed not too bad but the main casting had corrosion on the o-ring seats so we shelved it for the time being and went in search of a replacement on the basis that we had problems to solve on the main valve that might mask problems on the piggyback valve and vice-versa were we to try mending them simultaneously.

We knew that both evolved into the rapid start system on the V-Bomber force so a scratch around inside a Vulcan solved the problem…

There you go – a genuine M4901. A little grubby maybe but in full working order so we could use it to test the main valve when the time came but we had an outstanding issue with the main valve in that it contained a second, smaller valve designed to lift and at least warn anyone nearby to dive for cover should the pressure in the bottles go critical. To this day we’ve not fathomed out exactly why it’s designed as it is so all we could do was try to put it back as it was.

It’s a stack of tiny parts including needle valves and seats and springs and o-rings and something made of nylon that we melted whilst trying to get the thing apart and then had no hope of identifying – dammit!

Now around this time I received another of those mails from somewhere deep in the heart of a massive corporation from a man at his desk who wanted to help, one of those mails that suddenly changes the whole landscape. You see, ’til now, we’d had no real information about the parts of our system. Google, Lucas-Rotax and you’ll see what I mean, it just evaporated without a trace, but like the rest of British engineering it’s not gone far because it’d been absorbed by the mighty Goodrich Corporation and become part of Goodrich Power Systems.

Here, I was soon to discover, everything we could ever wish for was stashed away in their archives. Don’t you just love aerospace…

The problem was the lawyers. In principle the company was prepared to help but it took a while to get a disclaimer written up by the legal-eagles to the effect that if we exploded something they’d supplied drawings for we were firmly on our own. Being on our own is nothing new and being a diver I had a very healthy respect for the dangers of HP air so a deal was done and we presently acquired some archive info. An especially arduous task for the lady in the print room who uncomplainingly pulled dusty old drawings every time I asked then scanned and entered them into the modern system so they could be e-mailed. I sent her a nice bouquet of flowers to say thanks though I suspect a shiny, new car would possibly have been more apt. But could we work out what the nylon whatnot was that had melted over everything? Not a chance.

Around this time we also started swapping notes with Bill Vanryn.

Bill is a splendid gentleman of ninety-something who can quote part numbers, material spec’s, test procedures – you name it – and who also has a wealth of notes and data going back forty-odd years. His memory is incredible. That pic’ was taken in 2001, by the way. He’s also the engineer who was sent from Lucas-Rotax in 1966 to install and commission the air start system on K7.

Unfortunately, though, Bill couldn’t remember what had had nylon in it right at the bottom of the relief valve either. Barry and I had a crack at it next by laying out the parts and comparing them to the GA (general arrangement) drawing we had of the valve but its method of operation remained a mystery so we couldn’t second guess what might be at the bottom though Barry got the closest, as you might expect.

So we went back to Goodrich and slowly worked through drawing after drawing getting further and further into the sub-assemblies thanks to the dedication of the lady in the print room until weeks later when, at last, an innocuous little drawing turned up entitled ‘seat and cap assembly’. Eureka! We’d found it. It was a tiny nylon seat for a needle valve set in a stainless cup with an o-ring but without it we couldn’t keep the air in and without knowing what it was supposed to look like we couldn’t make a new one. I immediately mailed the info to Barry and Bill. Barry called to say he’d make one straight away. Bill suggested Barry didn’t bother because he had a couple in his tool box from 1966 that he’d pop in the post. Would you believe it!

And with that we completed the main valve or at least we had all of it in the same place but it wasn’t tested. We’d leave that until we’d connected up the other bottle as this meant a similar process and another, identical pressure relief valve. We stripped and cleaned the fitting from the other bottle.

You can see how the corrosion has struck along the grain of the casting and the sad fact is that the metal simply isn’t as good as what we’d expect today. It’s full of inclusions and impurities and the casting process just wasn’t up to scratch either so at least when we replace what’s been lost we know it’s quality material that’s taking its place. Once rebuilt and machined all it needed was the usual cosmetic fettling to make it look the part.

In actual fact this part failed its testing when a tiny leak appeared on its surface at 1500psi. Once the pressure was drained down and the fitting removed, fluorescent dye was applied to the outside followed by a black light shone into the interior to reveal where the dye had struck through a pore in the body of the casting. It was soon ground out and closed once and for all. We like to be thorough on this job…

Almost there, a little final finishing with needle files wouldn’t go amiss but mechanically it’s great. Notice the T-shaped handle sticking out to the left. That’s attached t