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June 2010

Whatever has happened to our milk?

Remember when you were a kid and the milkman left bottles on the doorstep and on cold mornings you could pop off the foil lid and the cream was so thick it wouldn’t pour?

And that was only on days when the blue tits hadn’t pecked through and nicked the lot. There was something endearing about small, blue and yellow birds getting up before you and stealing your breakfast – at least I thought so – and in the days when we recycled properly the empty bottles were then rinsed then refilled with fresh cow-juice squeezed straight from Ermintrude’s tits then given no more than a quick heating up according to a process laid down by M. Louis Pasteur to make sure there wasn’t too much listeria in the world.

I was sent to the little village store the other night for milk, something I never buy, only to discover that the do-gooders have assumed control of our moo-sauce too. Like light bulbs it seems you can now only get washed-out, fake milk. They call the blue-topped stuff whole milk but it bloody isn’t because someone has thieved the cream before the birds could even get a sniff and it only gets worse as the product they still call milk gets progressively more watery until you’d be forgiven for thinking they’d harvested quite the wrong bodily fluid. So-called, ‘whole milk’ is only missing its cream – though they charge you the whole price – but they do likewise for green-topped, semi-stolen milk that’s had the cream plus most of the rest of the good stuff taken out until you reach the red-topped slop that you could keep a goldfish in without too much trouble. Don’t forget, though, that they then sell you back what they’ve removed in your best interests in a hundred other dairy products then tell you not to eat it because it’s bad for you.

What’s actually bad for you is sitting about taking no exercise but try getting out on your bike for half an hour and the health and safety maniacs will have you dressed like a Christmas tree in fluorescent green with twinkling lights. The ethos these days seems to be that we need an environment, whether at home or in the workplace, where clumsy morons can hurl themselves at danger and bounce off unscathed protected by their gloves, glasses, boots and shortly, probably, full-cotton-wool-jackets…

The maniacs call me all the time in my office to ask who looks after health and safety within my organisation to which I reply, “We do.”

Then they rub their hands with glee and knowingly inform us that what we really need is a boy, straight out of school, having swallowed the latest manual on how fools can avoid injury while diving headlong into a combine harvester, to come and show us how it’s done.

“We use a somewhat outmoded though highly effective model,” I explain. “It’s called… (and I drag this part out for best effect) ‘common sense’. Ever heard of it?”

They tend not to like that very much.

I mean, divers don’t strap on their diving knife so they can charge blindly amongst old fishing nets, do they. It’s a get out of jail card if all your experience, planning and precautions don’t quite keep you out of bother (and for flicking your underwear over the side once safely back on the dive boat). So is it really safer to erect a million-foot-high scaffold with crash-mats and sky-hooks to change a lightbulb when your subject isn’t proficient in balancing safely on a rickety chair in the first place?

Angle grinders are my favourite. The maniacs tell us we should wear eye protection at all times yet not one of them can demonstrate how to use one safely without eye protection. Work amongst a group of blokes with grinders and it’s not their eyes you’ll get into bother over. You’ll only sprinkle their mug of tea with iron filings once before you learn to combine safe grinding practice with neighbourly consideration at which point your eye glasses become a secondary layer of protection instead of treating the symptoms of unsafe working practices. I invariably invite the H&S busybodies to come and run a training course in working off a ladder, balancing on chairs and angle-grinding without wrecking your mate’s cuppa and then show us how gloves, glasses and boots can contribute that little bit extra. It beats them every time.

And here’s another thing… they can never tell you what type of grinder ejects what type of projectile while working any given material and which are the bad ones so here’s a health and safety lesson born of long (and often painful) experience.

Bits of hot, abrasive grinding disc are quite nasty because they hit your cornea with a lot of residual heat and stick but they’re quite smooth and don’t scratch too badly whilst being easily removed with a cotton bud. Shards of stainless steel stick too and they’re anything but smooth so your eye protests angrily within seconds but they too can be quickly swept away with a cotton bud so long as you’re careful to lift them away as you go to avoid any scratching. For real anguish what works best is a high-velocity shaving of cast iron. They’re usually needle-sharp and red hot so they stick into your eyeball and weld themselves there with the heat. The trick with splinters in the eye is to shift them immediately. You can trail to A&E where you’ll be seen after all the overdosed druggies have been mollycoddled back into society but by then it’s too late. Once your eyeball gets angry all you’re going to get, apart from agony, is anaesthetic so you leave the hospital looking like a pirate, orange dye that makes the world look like it’s lit with sodium vapour lamps and a total stranger jabbing at the offending piece of shrapnel with a cotton bud just as you could’ve done yourself two hours earlier. One of those cast iron spikes can even mean scraping your eye with the blade of your Swiss Army Knife… that takes a little more resolve, but with a bright light, a mirror and a steady hand it works every time. Aluminium splinters are totally harmless, by the way, because they cool quickly in flight, have little mass and therefore little energy and never stick so they can be quickly blinked out.

There now – you’d not get that lesson from the H&S lot any more than they’d admit how painful a ball of molten welding spatter trapped in your steel-capped boot can be or how fragments can ricochet off the frame of your safety spec’s and hit you squarely in the eyeball anyway.

One thing though. Always wear your glasses when drilling hard stuff. Exploding drill bits are bloody dangerous!

Our health and safety prospects will improve soon, however, now that the daylight thieves have moved the clocks again. Just as we entered the bleakest winter since 1978 the fools wound our timepieces the wrong way to extinguish all hope of seeing our way home in the snow but now that spring is here they’ve given us our hour back when, let’s be honest, we don’t really need it. And – there’s now talk of us moving the clocks in the obvious direction next year and adopting double summertime by 2012. This could signify a loose particle of common sense that’s fetched up in the right place, or it could as easily be that they don’t want their Olympic running and jumping, spear-throwing contest going short of daylight…

Soon the sunlit evenings will be long and the grass will grow like the weed it is whereupon the footballists will hang up their boots and millions of kilowatts will be saved across the nation as cricketists don long pants and jumpers to leg it hither and thither in the blazing, summer sunshine. It’s in the sensibly warm summertime that the serious business of Formula One swings into action again.

Now there’s a proper sport, one which evolves year on year, where sponsors’ millions serve to move mankind forwards and feed the developing technologies of everything from crash survivability to fuel economy back to the populace. A sport where someone is actually in charge to enforce rules, punish those who transgress and ban refuelling making the first race of the year into a sad procession of overweight petrol tankers. It was dreadful but at least Rob finally had a chance to get even for all our digs at his chosen sport…


For almost five years now I have been teased in the workshop on a Saturday afternoon as I switch on my ball chasing wireless to warm up the valves to listen to my beloved team get beat once again. Apparently I should be into F1 for real excitement.

So it came to pass that sipping my tea one Sunday morning and channel hopping I happened upon this fascinating sport.

First few laps I thought were quite exciting but then the race ended. Or so I thought

..But no they had been racing to see who had the fastest car so he could start first in the real race? Surely it would be fairer for the guy with the slowest car to go first or even have a head start. Never mind, off they go again to the delicate screeches of Merriment Walker

And Stirling Sienna is in the lead with a thousand laps to go.

900 laps to go and Sienna still leads.

At this stage I went to 112 to catch the end of Bewitched. (I have always had a thing about Elizabeth Montgomery)

Turns out I missed the most exciting bit which has unfortunately been removed from the sport.


And Sienna pulls in for fuel, Excitement mounts as we watch to make sure he uses the diesel pump and not unleaded. Cost him £340.00 to drain the tank last time and almost certainly cost him the race. He is eyeing up the mars bars on the rack and oh no he has gone for the snickers. Must be the Geordie pump attendant cos when Sienna asked for some air he was given another 10 litres of fuel. Ready to go but there seems to be a problem. He’s refusing to leave the pits. Only been given single greenshield stamps, needs triple for a bottle of fizzy stuff to squirt at the end.

And he is eventually off to join the rest of the little cars for the boring bit.

Now you might think that that would be enough excitement for one day, and I wouldn’t blame you in the least, anyone would.

But no siree, Bob. These pit stops are a double edged sword.

While Stirling was in getting his fuel and a Ginsters pasty for the journey, my little mate from earlier with the crappy slow car. Who had to start last???? has caught up and seems for some reason to be ok for fuel and sucky sweets so doesn’t need to stop. Probably knows its only £1.14 a litre further down and he can use his premier card. And so we return to the commentary with Merriment Walker.

And Sienna is edging forward trying to rejoin the flow of traffic as Robs little mate in the crappy, little slow car who had to start last? tootles toward him. Will he flash him out? NO he has tootled straight past with a two fingered salute

Stirling is furious as he eventually gets out he knows that all of the overtaking lanes have cones on them so no one can overtake anyone any more. But wait Rob’s little mate in the crappy, little slow car who had to start last? has pulled into a lay-by and has disappeared behind the hedge Stirling flies past him and over the line. Another fine victory for the man with the fastest car who started first.

So, to recap. We have a sport where the handicap system puts the slowest bloke at the back. The only way to overtake is if someone needs a pit stop and the powers that be take out the pit stops. What chance does my little mate have against Stirling who is starting first not stopping and no one can get past?

If I have missed something, lads, please explain before 3pm Saturday when I will be warming me valves up for a proper sport.


…no, Rob you haven’t missed anything, on that occasion at least, but the second race in Australia was an absolute cracker with lots of overtaking, pits tops and not a ball in sight.

In the meantime we’ve been working hard on our own brand of motorsport.

One of the reasons we’re rebuilding an old Orpheus is that it’s all too easy to simply accept that this is what was spannered into the hole in 66 and not think any further. We had such a tussle with the museologists and lottery fools about how to handle history but at the time it never occurred to anyone that this legacy engine is, in its own way, another piece of our past that was slowly slipping into obscurity. As it happens the Bristol Orpheus is another mini-masterpiece of British engineering. It’s a small, compact turbojet from a time when turbojets were still something of a novelty and it boasted a number of innovative design features and an excellent power to weight ratio for its day. The turbine bearing, for example, uses a total-loss lubrication system whereby an air bleed from the 5th stage compressor combines with a metered oil supply to blow an oil mist onto the centre of the bearing from where it’s centrifuged into the jetpipe and simply burned off.

Bristol Siddeley sold it a little better than this when describing it as a ‘non-scavenged’ lube system that reduces the amount of plumbing and obviates the need for an oil cooler.

So long as your oil duration exceeds your fuel duration, it’s a neat way of lubing the back bearing and the little Orph’ was full of clever tricks like this so we thought rather than just spooning a nice clean one into K7 and happily showing off our new engine it would be more appropriate to rebuild an old one and teach you all a bit about how it works. (And ourselves too)

Our decision has inspired a fascinating journey all the way to the early fifties and back again and given us the pleasure of meeting some fascinating people.

I recently met with some of the engineers from the company that’s overhauling K7’s engine-driven fuel pump where we examined a set of springs from behind the pump pistons. Basically the Orph’ has seven combustion cans and the pump has seven small pistons to shove fuel their way with a spring behind each one. As may be imagined these springs do a lot of work and due to the pump design should one break the bits drop between the spinning pump rotor and a machined port-opening that immediately slices and dices the broken spring into thousands of tiny pieces then pumps them right through the engine. We don’t want that to happen.

For this reason the springs are a critical item and are usually replaced at overhaul but because K7’s pump dates back to 1959 it wasn’t certain that replacement springs were available. I couldn’t imagine what all the fuss was about because they certainly didn’t look like much, just springs really. Having speculated inwardly I then gave voice to my thoughts. It wasn’t a clever thing to do.

“Don’t know what you’re talking about, do you…” said one of the engineers with a twinkle in his eye.

All I could do was grin and agree.

I soon found out that before the springs are ever made into springs the raw wire has residual stresses set up in it by shot peening (the firing of tiny balls at the surface to cover it in a tensioned skin of microscopic dents) before being springified… That way the material can be stressed beyond what it’s theoretically capable of doing and become a very clever spring indeed. I moved on swiftly.

On another occasion we were discussing the elastomers in the fuel control system – rubber impregnated cloth diaphragms, mostly, that control servo-pistons and assorted rocker arms – and how they would definitely need replacing. Brand new and packaged they have only a relatively short shelf-life. Even properly inhibited inside a complete pump they don’t last more than a few years so a set of 1959 examples definitely wasn’t languishing in the stores and even if it was we’d not dare use it so we (or rather our sponsors) were faced with re-manufacturing the parts to a specification that hadn’t seen the light of day in half a century.

With ever an eye for K7’s originality, not to mention the scale of the favour I was about to ask, I suggested we re-use the originals because they looked and felt good as new and there’d be no real harm done if our engine ground to a halt halfway down the course.

I got that, ‘you don’t know what you’re talking about’ look again and they were right again. The problem here would not be the engine simply giving up and spooling down – what would happen is that should the pressure used to govern fuel flow start weeping through a pinprick in a diaphragm the engine wouldn’t stop at all, it would run away with itself, pouring ever greater quantities of kerosene into the fire until it howled itself to destruction in an explosion of hot shrapnel. We didn’t fancy that either.

There’s no denying that these pumps are robust little things and even in the broken spring scenario I was told the machine would ‘keep on trucking’ – for a while anyway. The modern version with carbon slippers on the piston ends and a host of incorporated cutting-edge materials can do an astonishing 22,000 hours on the wing between overhauls but having been warned of the dangers it would be grossly irresponsible to plough on regardless without thoroughly addressing all the safety issues. The elastomers are being re-manufactured…

We’re extremely fortunate with the engine controls but not so with the start system, which is both completely bespoke and was manufactured by Lucas Rotax, a company that’s long gone. There’s no spares or engineering support so we’re completely on our own in understanding and rebuilding all the twiddly bits that make it work but at least the start bottles are straightforward.

They’re spherical pressure vessels; one fitted either side of the inlet trunk on a steel frame. We always had high hopes of resurrecting them because the system remained pressurized during the boat’s long sojourn on the lakebed and when compressed air started hissing out after we’d cracked a fitting we all ran like hell. The reality seems to be a little different in that the right-hand bottle stayed dry because the main air valve and pressure regulating valve remained firmly shut providing a double barrier to water ingress but the other had a much simpler arrangement at its neck and ended up partially flooded.

Following much deliberation we decided to tackle the easy one and soon had it cleaned so we could inspect it inside and out. The dilemma we faced was that in order to get it through a hydrostatic test we’d have to shot-blast it losing in the process all the original paint and inspection stickers. If there was no chance of it surviving the test we’d have been better conserving it as a museum piece and finding another way to start the engine.

First we had the colour properly matched and a tin of paint mixed then all the stickers were meticulously measured, photographed and their position on the bottle recorded before the bottle went to the blasting dept…

Looks like the surface of some distant planet, doesn’t it… The blasting was intended to reveal any surface pitting. This doesn’t occur on the inside because it was dry but out here it swilled about in an electrolyte amongst a cocktail of other metals and suffered its share of dissimilar metal woes. Having consulted with several experts we were signed off to dress these pits with a die-grinder then build up the wall of the bottle by welding with the appropriate filler rods. It worked like a dream.

Next, give the repairs a good polish…

The neck had pitted too so that was carefully rebuilt and the wire-locking holes re-drilled.

Perfection… but would it take a test? Detailed boroscopic examination of the interior showed it to be in excellent condition but the proof would be in pumping it full of water. That’s how it’s done… were the bottle to fail when full of compressed air it would be like a bomb going off so the bottle is pumped up with high-pressure water instead, which is incompressible so far as the scope of the test is concerned, so if the bottle failed we’d get soaked and disappointed but no more.

The bottle was plumbed into the test rig and calm as could be the man opened the valve and a small Haskell pump relentlessly bumped up the pressure until it was stopped at 3200psi.

Each bottle holds approximately 17 litres of air at 220 Bar or 1052 cubic inches at 3200psi. The start system uses a pound of air a second and the start sequence takes six seconds so the pair of them together were good for twelve starts but to achieve a working pressure of 3200psi we’d have needed to test the bottle to 4600psi (that’s the test pressure stated on the label though these days the test pressure would be nearer 4800psi).

What we decided to do was test to the last working pressure – that which Donald used in 66/67 – then impose a new max working pressure of 2000psi. Assuming we can achieve similar performance with the other bottle we’ll have a much lower stressed setup that’s still good for at least a half dozen healthy starts. Let’s see what happens with the other bottle, eh – not to mention all the valves and twiddly bits we’re rebuilding to go with it.

Speaking of rebuilding – we’ve been getting all adventurous with the cockpit opening again. The past few years have been a huge learning curve with us first wondering who we might get along to make the complex shapes needed to rebuild the pointy end of our boat and then, on discovering that not many people actually know how to do this and even fewer on a volunteer basis, we chose to have a go ourselves and built this.

It wasn’t actually too difficult to fabricate from new, 1.5mm sheet alloy and it looked great but a certain piece dragged from the lakebed wouldn’t lie down and die quietly. It just looked too good to ignore.

That blue bit popped off and sank in the crash in remarkable condition and we often wondered whether it might graft back in as an original piece of outer bodywork.

Sure enough…

It worked a treat and we were all smugly pleased with the result but that’s where the matter rested because shortly afterwards we tore the boat down again to have the frame painted and the cockpit opening went into storage.

Fast forward a couple of years and the time came to have another look. But by now we’d got better at our night and weekend tin-bashery and thought another piece or two might save.

Like this, for example.

OK – so it was a little ‘crumply-dumply’ as my four-year-old would say but we’re not scared of things like that any more and a few strategic whacks with a hammer had it looking marginally better.

Now it only takes a small amount of imagination to see the curved cockpit opening at the bottom. One of our sponsors came to visit last week and having looked about awhile said, “Who could ever have imagined that all that scrap you pulled out of the lake could be turned into this?”

What could I say?

Some more tin-bashing and we had another piece ready to be grafted back in.

What we did in this case was to pin original over new then slowly cut away the new material and shape in the edges for welding until a big chunk of it eventually fell away effectively replaced by old tin.

The final piece in the jigsaw was the end of our panel.

Crumply-dumply to begin with but then…

…flat as a billiard table and, believe it or not, flat is by far the most difficult shape to achieve when starting with a non-flat piece of tin. Notice in this shot that the curved section of cockpit opening has now been grafted in and the panel is almost completely original except for the flat bit that wasn’t to remain flat for long because the next job was to put its shape back.

There you go… use it to replace the new tin underneath and hey-presto, a mostly original left-hand half to the cockpit opening.

Job’s a good-un… It’s had a sprinkling of patches inserted to chase out some rot and one or two fragments of the new-build panel remain but it’s essentially original.

The opposite side was a different challenge altogether.

Whereas the left came out of the water in scattered pieces with bits missing we discovered the other side complete and intact albeit somewhat crumply…

Particularly notice that big dig in the cockpit rail halfway along. That’s where the inlet lip got it when the boat folded in half. The inner rail was the same but we’ve mended that already, which is why you see it running straight and true behind the wrecked outer.

In this case, because we had all of it in one place, the decision was taken to dispense with the new-build panel completely in favour of rebuilding the original from scratch. We’d already gone some way down the other route by grafting the mostly intact curved cockpit opening into the new-build panel so that didn’t form part of our game plan at the outset and was recovered later.

Job one was to assess where the various twisted pieces were welded together then cut it apart along the welds. There’s simply no way you can make this shape from a single piece of material so it was fabricated from several sections and glued together.

Fortunately we’d already done the exercise on which was what in order to build the new panel so accurately cutting up the old one was a done deal.

Makes a little more sense now, doesn’t it, and notice also that the section in the foreground has already had some repairs carried out. We patched it to get that bottom edge straight to use as a datum for setting it up again. It started out torn in two with a big rotten patch in the centre where the forward end of the spray baffle was fixed with steel bolts about three inches long. You guessed it – dissimilar metal rot.

The affected area has been marked up ready for ‘loofing’ and you can see that the two, torn halves have been spot welded back together. The rot along the lower edge was caused by more steel screws used to secure the bodywork.

Getting there… you see the idea. Using that process we brought the pieces close enough to start setting up. Those dull patches on the sides of the piece, by the way, were caused by the shrinking disc but more of that later.

So far so good… At this point the outer rail has been freed of its nasty dig and it was here that yet another challenge came to light. You see, there’s a half-inch difference in length between the inner cockpit rails. The left one is longer than the right. It’s definitely not impact damage because they’re quite heavily built and no way is there half an inch difference due to the crash. It’s almost as though the cockpit halves were built by two blokes who couldn’t stand the sight of each other.

The problem was where to put the difference. Send it to the front and the semicircular opening would lose its symmetry as would the canopy that must fit to it so that’s no good but send it to the back and it’ll misalign the air intake throats. From pictures we have of the inlets under construction in 54 it’s plain to see they were built to the nearest inch so the problem may have been with K7 from the outset but there’s no way to tell so we decided to put it back symmetrically by reworking the outer rails. First things first though – we needed something to tie all the pieces together and that’s the job of the flat, horizontal deck, which we cut in two because it had a nasty stretch in the middle that wouldn’t chase out, well it would, but cutting it in half was a far simpler solution.

If you look in the background above you can see the new-build panel with the original curved opening grafted in. That was recovered next and put back where it belongs.

And so on and so forth… The second half of the deck was quick to follow.

From here it became a long, drawn out process of cutting-in the edges and welding followed by taking the tops off the welds with a die-grinder then hammer and dollying the welds to stretch them. It’s painfully slow because every weld is a most effective shrink in such a thin panel and if left it will hold the next area in the wrong position when its turn to be welded comes around. Even with everything in the correct place it’s still a case of slowly-slowly because heating the panel will also change its shape and there’s no point capturing those changes by welding things while it’s out of shape so you need to set up and perform each small repair then stop until everything cools and return to the shape you wanted before carrying on.

Works though…

Notice here how the panel has been grown downwards by the addition of a strip of new material. This allows for clamping the piece to the boat – something that’s impossible with the skin at the finished length – and to let us trim the finished job to perfection.

Next we had to start on the details and this is where weeks and months go by with no visual progress. Here’s an interesting detail.

In the accident the front of the boat came to a standstill almost immediately but the big, heavy lump behind it took no notice for about another nine feet and ploughed through the stationary wreckage wreaking all sorts of havoc. K7 is built such that all her structure concerned with keeping the water out is below the top of the frame whilst all the aero stuff is above and therefore gained no benefit from the strength of the frame when the water came up to meet it.

Now here’s something most peculiar. You see all these repairs going on, pieces of bent metal being straightened… 99% of the problem is getting rid of stretched material and shrinking metal is proper witchcraft so it’s amazing to find that parts of K7’s structure were hit so hard and so suddenly that the metal was actually squeezed into itself and shrunk by the impact.

This is the original closing piece from the aft end of the right-hand cockpit opening.

Stay with me here – it’ll all become clear. This piece was recovered from the wreckage, beaten somewhere near and then set up from whence it came. Next it was built into a replacement end for the panel by the admixture of some offcut tin and a welding rod or three. Cleaned up it looked fairly presentable.

Then we slapped the devastated end of the panel over the top and you can see the problem.

It’s about an inch short at the outboard end and this is entirely due to the fact that in a split-second the front of the boat decelerated violently while the aft section carried on. Frightening, isn’t it. That metal has squeezed in on itself like Plasticine and become thicker leaving it way short of where it used to be. We could bash it thinner again but we elected to let in a new piece instead and leave the artificially thickened metal with it’s artificially enhanced strength. We saw exactly the same effect at the aft end of the seat formers though they were subsequently stretched again with a hammer because they were completely intact only the wrong shape.

The other side was exactly the same so we cut and shut it appropriately. You can see here just how much metal had to be added to true up the back face of the foredeck.

That’s the shape sorted. Still a world of fiddly stuff to do but we’ll come back to that.

In the meantime we’ve been pulling our hair out (maybe not in my case) over another problem. Since the off we’ve always vowed to inhibit the inside of K7’s frame tubes against corrosion before she takes to the water again. The 1966 inspection by the RAF describes corrosion to the insides of the lower tubes consistent with what we see today and this seems to be a combination of her plunge in Lake Mead and her general neglect as she got older. It’s not got any worse during her 34 years on the lakebed but as we expect her to outlive us all part of our plan is to dose the insides of her frame with some Chemetall wizardry in the form of their Ardrox AV80. It’s horrible, brown stuff that sticks to everything it touches and glues your fingers together while nothing will wash it off and it spreads further and faster than baby poo once it gets away from you. It also protects bare metal like you’d not believe by drying into a tough, slightly tacky varnish from which water flees and it will take knocks and bangs without flinching; but how to apply it 23 feet up a 2-inch box section tube?

What we really wanted was a mist rather than a spray because Ardrox is very expensive and what we don’t use we’ve promised to the Concorde project at Filton so we didn’t want to pump gallons of the stuff into the frame just to have it go to waste.

Cleaning the longitudinal tubes proved simple enough. They were full of dust and rivet stems so we opened them at the stern and went inside. As you look at the back of the boat there’s a three-quarter-inch brass bung to drain the hull screwed into the frame at the bottom left corner so that was open already. All we had to do was put a similar hole in the other three corners and we were in business.

We used a rearwards-facing jet on the end of a length of 8mm brake pipe to blow the debris aft. The brake pipe was both rigid and flexible enough to penetrate all the way forwards past sleeves or where we’ve made repairs then the air was turned on and the pipe slowly drawn back. It was remarkably effective.

Three or four passes down each tube and they were spotless inside and we had two big tubs of rivet stems to add to our collection. Next we had to get the Ardrox in there. Propelling it was simple.

To the untrained eye this may resemble a fire extinguisher but it’s actually our Tube Internal Treatment System comprising a pressurized reservoir of Ardrox and a precision metering system. To this is attached a long lance – not unlike the 23 feet of brake pipe we used to blow the crap out of the tubes – with a spray nozzle on the end. But how to atomise Ardrox…

You’d think it would be a simple matter – just pop a suitable nozzle on the end and away you go – but it wasn’t. Nozzles are a science in themselves and everything we tried only resulted in gallons of Ardrox shooting from the end of the pipe like a racehorse relieving itself. Time to talk to a nozzle expert and to the rescue came a helpful gentleman called Roger Faulkner of PNR nozzles.

Roger kindly sent us a selection of small nozzles to try…

…but still we couldn’t get a result. More consultation with Roger and we made a small but vital modification to the T.I.T.S. and we were off. Suddenly we had a perfect mist of Ardrox and then the fun began.

Ardrox-man, as Rob soon became known, and his sidekick, ‘Mikosquirt the Atomiser’ were soon hard at work misting the length and breadth of K7’s internal passageways with gloopy brown liquid. It wasn’t long before the stuff started coming back out again…

The workshop floor looked like a crime scene with ‘bleeds’ of blood-like Ardrox springing from everywhere but at least we could be certain that the insides of the tubes were thoroughly coated, something later we later confirmed with our boroscope.

Next – prepare to stick some bodywork on.

Two things here. First – the entire suit of outer skins must be assembled starting at the stern; this because the panels are overlapped in such a way that the water is never allowed to force two skins apart.

You can see how it works in the above sketch. Now follow this to its natural conclusion and you soon realise that the first panel fitted has to be the one right at the back – the transom.

The other issue with the outer skins is the clamour that’s been going on for many months to see some of them fitted. The huge amount of painstaking work done by the team to turn out a perfect hull structure counts for nothing, it seems. All anyone wants to see is the wallpaper being hung. Grrrrrr! So we made a token gesture.

The problem with fitting the transom is that it’s where the rollover jig bolts on so the first thing we did was press one of the original lifting frames we used to get the boat out of the lake back into service to hang K7’s rear end from the ceiling.

Doing this with the boat inverted gave us two advantages. First, we had a better working height and, second, the upper frame tubes at this point slope downwards whereas the lower ones are parallel with the floor so running a 5000kg strop through the frame then onto the eyes at the ends of the lifting frame was simple. We took the weight then did a bit of housekeeping – a tiny amount of hot-work on some patches Mike Ramsay carefully filed from frame offcuts were used to close the Ardroxing holes.

We didn’t really need to do that as we’d opened them between the pre-existing rivet holes and they didn’t compromise the frame’s strength at all but we could so we did.

In the interests of thoroughness we popped an aerosol lance through the rivet hoes and Ardroxed the backs of the patches and the fronts were treated with Oxsilan to look after them until a gallon of choccie sauce was slapped over the top. Next we took the weight and gingerly stripped away the rollover jig. We’d not tried anything like this before so we were careful in case anything shifted unexpectedly though the physics of it said it shouldn’t. Sure enough, nothing budged.

The orange bucket, by the way, is to contain the lifting chains and keep them off the paintwork. Considering how much repair work we had to do on the transom I’d been quietly concerned that it was going to fight us when we tried to put it back but it gave in surprisingly easily when dry-built. Some stress-relieving was needed with a rubber mallet but generally it came quietly.

Meanwhile, Youth had seemingly vanished but was subsequently found under the suspended hull quietly cleaning Ardrox ‘bleeds’ off the frame until we chased the silly bugger out of there until the jig was reinstated!

We also failed to notice – mainly because us middle-aged gents, having lugged our abused carcasses this far through life, tend to take belated care of what’s left – that he should’ve put gloves on so he got Ardroxed hands for his trouble too.

So with the dry-build a success we mixed a bucket of choccie and got going.

Having keyed the paint with fine abrasive paper to ensure good adhesion we coated up the back of the frame then, following similar preparation inside the transom, another layer went on there.

Then we carefully aligned the holes and clashed it on.

This is where another story meshes with our progress because some time ago we realised we’d need a large quantity of rivets that had to perform to a very high standard in both holding the boat together and keeping the water out and I don’t care how simple the aerospace community say rivets are – they’re bloody not! The part numbers and specifications are an absolute nightmare with a thousand-million ways to cock it up so what we wanted was a man (or woman) who could point at the holes and say, you need an ABC/1234 to go in there. Enter Chris Houghton of Cherry Aerospace whom we called and said pretty please with sugar on until he was kind enough to not only tell us what the hell we were doing but also to arrange for a quantity of the very best rivets that money would normally have had to buy to be donated to the project.

And what a fantastic job they are too. CherryMax AB wiredraw rivets. The closest tolerance parts that Cherry Aerospace make, I’m told, and did they work? Did they ever…

What you ought to realise is that fitting the transom took an entire Saturday and there’s not many of those in a month and this is why progress can sometimes seem slow.

Another build relentlessly munching onward is that of K7’s new powerplant, which is now looking absolutely splendid on its Bettablast-painted cradle.

It’s half the battle having everything clinically clean because that’s your yardstick when keeping it that way. Likewise, if you build everything to a quarter millimetre one day you wake up to discover the whole job has turned out the right size and shape. Simple philosophies that make all the difference…

Our engine has been treated this way both inside and out and day by day parts are added until, just like the boat herself, sooner or later there’ll be nothing left to do but press the starter button. The oil tank is a good example. It’s made of stainless and therefore survived in good shape but many of its fittings paid the price.

Here it is as-recovered but look at where the oil pipes screw onto the right-hand end and you can see that the steel fittings have disappeared completely. It’s not a clever idea to put fine stainless steel threads together because stainless on stainless tends to spall and lock the thread so the fittings were ferrous and consequently dissolved to a biscuit-like material that crumbled to the touch and was lost forever. And though the filler cap appears largely intact it didn’t fare too well either because the corrosion was right through the grain of the metal and the second it was exposed to air it began to rapidly deteriorate despite everything we tried to minimize the damage. The new one is pretty though.

Having it made was challenging too because the machine shop I asked to tackle it is full of proper craftsmen but even they like a little more than a crumbly old chunk of alloy, an oil tank the likes of which they’ve never seen before and a few old photographs to work from. They made it happen though and what a beautiful job it is – likewise the new fittings for the ends of the oil pipes.

Of course the ends of the pipes had to come off in order to slip them over but we’re used to such things and they were quickly welded back on again.

Just another few original parts being worked back into the rebuilt boat. It’s a long time since those pipes felt hot oil pulsing through them and they could so easily have gone in the display case with the rest of Donald’s dead Orph’ but no, they’re going back on the new engine as soon as we’re 100% happy with the oil system. It’s needed some nurturing because our engine stood outside for rather a long time and because of the type of material the gearbox casing is made from you have to be plenty careful of the effects of water ingress. Despite stripping and cleaning every crevice and oilway we still didn’t want to put our brand new, specially-built oil pump in the circuit until we could be sure a chunk of magnesium hydroxide (or brucite, as it’s more commonly known) wasn’t going to float down the pipe and gouge lumps out of the pump chambers. Just to be sure we built a test rig to simulate the pump functions, a sort of artificial heart.

On the right is the good old T.I.T.S re-rigged to supply hot oil at 7 Bar and that vertical, black cylinder is a scavenge tank. The air drill lying on the cardboard has an improvised fitting that slots into the splines in the front of the engine mainshaft so we can spin up the compressor. The scavenge tank has Henry-Hoover plugged into the top and a pair of 8mm plastic tubes emerging from it inserted into the two scavenge oilways in the bottom of the gearbox. Switch on Henry and he evacuates the black cylinder slurping the scavenge oil into it.

As well as the main pump there are two others in the Orph’. One is an auxiliary scavenge pump to pull oil from the back of the gearbox and throw it where the main scavenge pumps can get at it. We checked this one out when the gearbox was stripped. The other is a metering pump that delivers periodic squirts of oil to such things as the bevel gear drive from mainshaft to gearbox and the turbine bearing at the back of the engine. We had to spin the engine while injecting the oil to be sure the metering pump and ancilliary scavenge were running too.

Most of the rigging was done by another Rob, or ‘Checkie’ as we call him due to his partiality to checked shirts. He’s at the back there trying to stop oil pouring from the nose of the engine while on the floor, with his finger jammed in the drain from the fuel pump that spewed oil because the pump’s not fitted, is Laurence ‘Lozza’ Chapman who came to get his hands dirty for the day. Lozza flies planes for a living but normally has someone else get covered in oil on his behalf.

We spent a fascinating couple of hours blasting gallons of mad-hot oil through passageways then trying (largely ineffectually) to contain the deluge that came back out again but the procedure was only a partial success because we were unable to make the turbine bearing oil-feed perform as expected. That’ll have to be investigated and put right when we get back onto it because that’s enough engine tweaking for now.

We tend to sicken ourselves with tin-bashing then go off to be jet engine techies for a change of scenery but the tin-bashing scenery is changing anyway and with K7’s structure now more or less complete our attention turns more and more to making her watertight. Next time the diary is updated the boat will likely be skinned over half her length. We’ve dry built her for a look-see…

There’re some weary rivet holes to lose and we’re investigating a build sequence that will let us assemble and fully rivet several of the panels before they’re loaded and fastened down. This (hopefully) will save a world of pain trying to set rivets in near-impossible corners – we’ll see.

Oh, and before I go… remember I mentioned the shrinking disc and more of that later? Well this is the most genius piece of kit ever invented for tin-bashing and if you like to mess with cars or seriously injured hydroplanes then it’s a must-have gadget.

It’s also a health and safety maniac’s worst nightmare. It’s basically a stainless steel disc with a turned up edge and what you do is throw the guard off your grinder and shove this on instead. Then you spin it up and wrestle with the immense gyroscopic forces until it’s positioned over the lump in your tin that you want rid of. It works on the most ridiculously simple principle – friction.

What happens is this. If you heat metal then quench it suddenly it contracts and shrinks. Repeat this process and you can dispense with some fairly hefty bumps in your wounded hydroplane. You can do this with a gas flame as you’ve probably seen us doing before but the trouble here is the speed with which heat soaks through aluminium and the slowness with which a flame pours it in – you end up working quite a large area. You can get around this with an oxy-acetylene flame but it’s way too hot making it easy to melt a hole in your panel. This is especially a problem when you have a series of small crowns near to one another as all you want to do is get rid of the crowns without shrinking the whole area. This is where the shrinking disc is absolutely brilliant.

What you do is push the spinning face of the disc against the crown on the metal and it heats where it touches – simple as that. Once it’s hot, and it only takes a mo to come up to temperature, you blast it with a spray of cold, soapy water. Or ‘surpy watter’ as we call it, derived from the phonetic spelling of the Geordie pronunciation. The surpy watter instantly shocks the hot metal into contraction then you reapply the disc and repeat as necessary until you’re standing in a puddle and everything you’re working with, including your grinder with its mains electricity supply, is dripping wet. The din is unbelievable and the disc will pick up and fire shards of mad-hot aluminium shrapnel if you let it get too hot, assuming it doesn’t take a hold of the sticky metal and catapult the spinning disc at your face. Like I said – the H&S maniacs would faint at the sight of such a lethal device but what a piece of kit and, like any slightly dangerous tool, a little common sense will tame it.

And finally… I was told recently of yet another H&S nutter who recently inspected a fully armed Tornado on the front line. It had 6000lbs of high explosives lashed to its belly, it was bursting at the seams with kerosene and was about to go airborne in a war zone but the aircrew couldn’t get aboard because the steps didn’t have a handrail…

Until next time…

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