Right – that’s the sticky-up bit done, bar the snagging, and we’ll show you that in due course. But it was always going to be a bit of a cheat because, apart from the squished leading edge, there was hardly a mark on it. The elevator was challenging, mainly because we had to tame the material, but at the end of the day it’s about six million widgets flying in close formation so if it’s a bit crooked then a push here and a pull there will see it right and if that doesn’t work it’s because it got dinged by a stray shell from Tirpitz, (honest) which happens to be one of my favourite shipwrecks, by the way – but that’s another story.
But the tailplane is a different gether all to case...
It didn’t arrive as one battered lump, nor could we create it from scratch and get way with it, albeit with old material, as we did with the elevator. It’s eighteen feet across and arrived in three crumply-dumply sections and we’d not have to reassemble it very far adrift for it to look bloody awful.
We’re not into telling porkies either so we must confess to the inclusion of a smidgen of high-build primer on that leading edge. Elvis did an outstanding job but filler, of all things! I hate the stuff. If you need filler you’re not finished with the metal or you’re living with something that didn’t come out as you envisaged (or you have to work within reason to turn a profit) but the metal was all out of ideas this time because of the amount of work we’d had to do on it so we quit while we were behind having learned enough to do a better job on the other side. Another problem with the leading edge is the order in which the tailplane was built first time around – from the leading edge backwards, but with all new parts that fit first time – a luxury we simply don’t have. Because every last part has some sort of stretch or crumple we must set some values in stone as we go in order to have a means of determining whether a piece fits properly or if it doesn’t.
So we stuck the leading edge on in isolation. It would normally attach the skins immediately aft of it at the same time but we still need to mend those.
So we nailed it into the extrusions that run up either side of the front spar with countersunk blind rivets leaving all the original holes for when the skins go on – a bit of a cheat, admittedly, but you can’t say that we lied to you.
Notice also how some of the rivet heads on the leading edge are being swallowed by the dreaded filler. That wouldn’t have been the case when it left the factory so we’ll have to think about that one or it’ll not look right.
We also Ardroxed everything underneath before closing in the voids.
But, crucially, what adding the leading edge in its final position allowed us to do was check the outer skins for fit and finish in such a way that if we tweak them around to fit the hole we’re not going to come back to find the hole has changed shape later.
OK – so the skin in the foreground has a jagged tear right through the middle of it (where the bread knife got it) but that’s neither here nor there. You can see that the outboard end is covered by two skins – the lower one having been removed in this shot. Now take a look at the upper in closeup and what do you notice?
Yes, you got it in one – the rivet holes along its upper edge have disappeared. Didn’t get it at first really, did you. Bet you had to go back for another looky-see. But they’ve definitely gone, vanished using long-ago perfected techniques born of building a tin boat. What this means is that we can put them back wherever we want so there’ll be no residual stresses just like a Eurofighter and nothing at all like a Fairey Baddacooda and that’s most of the reason why our tailplane will not to come out a funny shape.
We’ve needed a few more fixes on the inside too. That turnbuckly thing has its very own rib; it must be an afterthought because it’s number 4a. There’s one-to-four (one to nine actually) but then they shifted the tailplane from the bottom, where presumably it was fluttering uselessly in the knackered air behind all those wing flapamabobs, and stuck it up top then added the struts to stop it falling off. In so doing they added an extra rib just inboard of the real No. 4. And, let me tell you, folks, when you crash your Baddacooda the top rips off that rib.
And then you have to weld tiny bits back on.
It’s a bit of a pain mending all these little fiddly things because it takes as long as mending a big piece but it has to be done or chunks of aeroplane will rattle about loosely inside your tailplane when they should be bolted down.
Look on the bright side – it’s a great way to use up the smaller scraps of BOOB. This is where it goes.
Now you’ll remember how we cleaned up that steelwork you see above using a rotting bath of molasses? If not, pop back to last month’s diary for a look. The result was most impressive and it took us neatly into the next phase of the project. You see, with the sticky-up bit more or less done and the tailplane ready to have its clothes put back on we have now turned our attention to that ugly conglomeration of tubes down below that it all fixes to.
What it seems to be is a sort of push-me-pull-you arrangement of tubes with adjusters everywhere so you can do the usual job of bending something out of shape with a few turns of a spanner if your plane happens to fly in unbidden circles. It also picks up the tailwheel and the assorted fairings that fasten on to make it all smooth and aeroplany but it’s going to be the very devil to dismantle unless we do something clever with it. More molasses – that’s the answer. To that end we acquired a huge plastic bathtub. Trouble is, we know from Richie’s tank-cleaning escapades that molasses can’t munch through grease so first-off that had to go, along with the muck, before the sugar gets a turn.
So we mixed up a gazillion gallons of Ardrox 6514, which is a caustic de-soiling substance that comes in a plastic sack and looks like washing powder, and dumped a tailwheel thingamy in there.
Fast-forward a week and out it came looking much cleaner than when it went in.
Our one and only intact one of these came out all scrubbed too.
That’ll all have to be stripped down and mended too in due course. We have a few examples of its upper half as that doesn’t mind being crashed so much but the fork arrangement at the bottom that holds the wheel seems to spang off into the undergrowth never to be seen again at the slightest provocation. This example came out of the sea, apparently, and is in a remarkable state of preservation despite this. Note how the alloy centre of the wheel has completely dissolved leaving only the tyre rattling around on the forged steel fork. But, most importantly, the steel is completely unharmed through the electrolytic sacrifice of the more reactive wheel. Clever stuff…
We have the drawings for that big gas strut thanks to Will at the FAAM and we know that it’s supposed to be charged to a billion psi but I doubt very much we’ll have good enough parts to stop it leaking so at some stage we’ll have to work out what height it normally rests at and saw a piece of broom handle to shove inside.
We got the elevator hinges ready to put back on too after they’d been tickled with the hot-spanner and pulled down. We did the inboard ones a while back and even stripped and rebuilt the original needle rollers, though I’d not want to go flying with them in their somewhat rattly condition, but at least they’re original.
Here’s a stripped hinge assembly.
The needles were badly seized into the track and rusted onto an inner sleeve, which had to be pressed out. But behind the needles was a smothering of fossilized grease so for three quarters of their circumference they weren’t in bad condition. Fortunately the outer track had lube holes through which we were able to punch a few needles into the centre bore to get the thing into bits and we were off.
We steeped them in a few potions and lotions to shift the grease and corrosion product then cleaned each individual needle with Scotchbrite before reassembly with a dab of moly grease.
Gillian spent many-plenty hours giving all the widgets from the back edge of the tailplane a light blast to remove the grime and give a good key for the etch-prime.
For those unfamiliar with surface coating, the problem with painting anything made of aluminium is that it’s much too reactive. Sand it, file it, scrub it and all it does is immediately skin over with an invisible oxide layer that acts like a loosely adhering film on its surface. Add paint and all it sticks to is the oxide and not the metal so when the oxide falls off, which happens pretty quickly, the paint goes with it. An etch prime contains an aggressive chemical – acid usually – that munches through the oxide, grabs hold of the metal beneath and clings on for dear life allowing you to paint on top of that without anything falling off.
The hinges went back on… (They’re actually upside down here because someone who I won’t confess to being on this occasion forgot that the tailplane was upside down in the first place)
Fitting them is only temporary anyway but what it does is solidly attach the front spar to the back one then, with the admixture of a skin or two, we can uplift and manhandle the whole tailplane onto its side. Cool, eh. It’s huge too.
Once laid over, Aerospace Rob set about the final fit of the outboard skins on the starboard underside. They came off in fair condition with only a few puncture wounds from sharp rocks and the wingtipamabob mashed to buggery so it was an easy fix over there. Nor can we be sure how much of the minor superficial damage is original abuse so we’re careful not to go too far with the mending.
And seeing as this end is almost complete, Gillian did the final build on the starboard side catchitt.
It’s held in with masses of 2BA bolts and ‘hard-to-come-by’ washers and cad-plated nuts (that we explicitly told her not to eat) so once buttoned up it was impressively rigid and now you can believe that it would restrain a wing, but because all the captive nuts were slathered in Ardrox and etch-prime some of the bolts took a little starting. She nailed it in the end.
Meanwhile, on the other side, Hayley is gradually putting back the guts of the leading edge.
As was the case with the night fighter side, we have an incomplete set of formers so we gave her the drawings and suggested she knocked together some replacements. Now up to this point we’d carefully scaled the drawings, which are in a mixture of decimal inches and fractions, into millimetres then drawn out the parts on a spare slab of BOOB before snipping them out. Not Hayley – she took one look at the drawing, scaled a couple of important dimensions then disappeared upstairs to her office where she ran off a copy to perfect scale on her fancy photocopier that she then only had to cut out and draw around. No one likes a smart-arse.
Meanwhile, more of our unsung-heroines keep the supply of war materiel flowing smoothly.
The result being that we now have a genuine Baddacooda tailplane that we can heft about (if heft is the right word because it’s light as a feather) so all we have to do now is fill in the blanks.
There remains one or two minor challenges but nothing to keep us awake at night. Where the bread knives went through we have only partial remains of the ribs and, though we’ve not yet confirmed it with a tape measure, we’re just bound to have a stringer deficit so we’ll be into making some new bits there rather than straightening crumple. And there’s a large chunk of skin from the port underside still up a Scottish hill so the salvaged outer skin from the burned out tail awaits the treat of filling in for it but it’s of a heavier gauge so making the repair invisible is going to be interesting. Other than that we should be on a relatively smooth march to the finish line with our tailplane.
‘til next time…