Bit of a sour note behind this month’s diary, unfortunately. For those who don’t know, we’ve had a bit of shenanigans with our favourite museum these past few weeks, which is why there’s been no diary for a while. Out of the blue we suddenly came under pressure to sign a contract that’s been languishing in a drawer since early 2012 and when it proved untenable because it robbed us of our volunteer status and attempted to have us pay their insurance the plug was summarily pulled and demands made for the return of the broken aeroplane.
Of course, they can’t just do that and it was a knee-jerk reaction anyway so things seem to have settled down again now. We were, however, rather dismayed at several mutterings that apparently sought to stretch, bend or otherwise distort the truth but we’re gracious people and rose to our defence proportionately and no more.
It’s an odd situation, though, as the questions filter upwards through the museum. Naturally we’re not paying their insurance – that would be beyond stupid – but they have a hundred irreplaceable aircraft insured anyway so we’re sure their existing insurers will gladly pick up the tiny extra so, in the meantime, we just carry on.
It’s a little like if you took your car to a notable specialist with a fault that no one could diagnose or fix and they offered to mend it for free on condition that they could use it to educate the new apprentice and have the kudos of a successful job for use on their website. Then halfway through you decide, never mind, I don’t care about the fault, I just want my car.
The specialists would be perfectly within their rights to say, nope, we had a deal and we still want this for our website so go home and we’ll call you when the car is ready.
Hopefully the museum has sorted itself out by the time you read this. Either way, we’re gearing up again for a renewed spot of tin-bashery and until further notice the Barra’ project is back in business.
As you might imagine, with the workshop standing unused for a while all the good tools, once jealously guarded by Aerospace-Rob and the Barra Babes, have been snaffled by those pesky boat builders next door but that’ll take no sorting out.
At the moment we have two major tasks ongoing. One is to finalise our plan of action for dismantling the fuselage because that job was agreed and the scrap delivered as recently as October. What we do not want is this little lot all in pieces at the same time!
There’s just too much of it to keep track of all the bits so it’s going to have to be broken into sub-sections to be treated individually. On the plus side it’s all in big, relatively intact sections held together with only rivets and not multitudes of rotted nuts and bolts so Aerospace-Rob will frighten this stuff apart in moments once we give him the word to go.
The other job is to finish the tail. It’s incredibly close, needing only a single skin panel, its portside leading edge and the fairings where the sticky up bit meets the tailplane. They’re lovely soft alloy with zero corrosion and I’ve been looking forward to pushing them about ever since they arrived.
The tailwheelery is another matter – it being stupidly complicated it’s just going to have to lurk on the bench receiving crumbs of attention here and there until we’re ready to spanner it under the tail. That leg of Olay thing has gone all limp and floppy too so we’re going to have to find out where the gas is escaping. But, first things first – the leading edge... There’s only this side to finish but, as you know, the other side managed to lose some of its definition with more than the envisaged quantity of high-build primer. But that was early days and our skills are leaps and bounds ahead of where they were and this time the plan is to do a better job. It looks OK as it is, mind you. Remember, that’s bare metal.
We could just about paint that and get away with it and it would look no worse than the other aeroplanes in the museum but, as we have it in bits, I reckon we can do a little better. Over the past few weeks our volunteers have snipped and filed a few patches to make sure we have a full kit of parts. So, as putting a half dozen patches in to complete this leading edge section is about all we have to report, I thought I’d share some of the boring detail that normally gets firmly left out.
This is the inboard end of the outboard section – if you know what I mean – where the two pieces of leading edge meet in the middle. It’s actually at rib No.6, which is a curious beast in that it’s a smidge smaller than it would otherwise be so that a strip of tin can stretch over the top of it to allow the joining of the two leading edge sections. You can see another chunk cut out on the other side and as the patches have been made for a while out they came and were set up in the gaps.
They often take a little bit of final shaping once the time comes to fit them for real so this one needs a quick tickle just to eliminate any gaps but you get the idea. The patch is backed with a curved piece of aluminium to hold a gas shield behind it to ensure good weld properties. Then on goes the glue. Notice also that patches are always made oversize if they’re on the edge of a panel. It’s easy to make them smaller but it’s a bugger to make them bigger.
This is the other patch around the back (forgot to photograph the big one before it was dressed – duh!)
It’s not the prettiest weld you ever saw. Pretty welds are very difficult in this old material as it doesn’t always flow as you expect. Hit an inclusion in the weld-pool that won’t float off and next thing you’re stabbing furiously with a filler rod trying to stir it to the surface and the resultant weld looks like something a pigeon left behind. Cleanliness and preparation of all the metal before you start is absolutely paramount, the filler rod being the part that most people forget to clean properly.
As I say, not the prettiest weld but it ticks all the boxes. Excellent penetration and equally clean around the other side (won’t bore you with that pic) because the gas shield was contained on both sides. Good dilution of the filler and the native metal, which is why the weld is so wide and bulky. It’s a silicon rod too so it’s a little more difficult to get things flowing but it’s butter-soft metal that works nicely later on with less chance of cracking. And, of course, all the native tin has been properly heat-treated so it too will work as we require. All these small things add up to a process that allows effective mending of this old scrap.
The other piece of gubbins we needed for this end of the leading edge section was rib No.6 and its jointing strip that allows this piece of leading edge to be connected to the next bit. This one came from goodness-knows which aeroplane and was mildly squashed.
This is a complete – sort of – No.6 rib with the jointing strip still attached here and there. Plain to see that it’s come to a sudden stop. We didn’t’ need the rib because Hayley made a new one some time ago but we did need the strip, not least because it tells us if the other components are right. It took no freeing from the other bits.
Then it only needed annealing so it would behave, some shrinking here and there around the kinks, and then pinned into place.
The patch is almost blended too though there is another small weld on the top. That’s where a crack began to form and was repaired with the jointing whatnot in place. It’s almost impossible to snag every inclusion – and by inclusion I mean foreign objects in the weld – so inevitably some slip through. They can be pieces of pretty much anything but are usually corrosion product. Some float to the top of the weld pool but some don’t and to visualise the problem imagine including a small stone in a ball of Plasticine then trying mould it into something. The good thing is that they always reveal themselves if the metal is worked, just as the stone would pop through the Plasticine, then it’s a straightforward case of either grind them out or establish another weld pool and push the damn thing through to the other side with the filler rod where you can take care of it later with a die-grinder.
So that was the last of the patches, which meant that next the internal stuff had to go in. When it comes to ribs and such, Hayley is the undisputed master there (mistress, perhaps) because, if you recall, she converted all the drawings for them into dressmaking patterns then sewed them from bits of old Barra’. At last the time has come to put them in and as we’re cracking on again she took no persuading to enjoy some ‘aeroplane fun’ as she calls it.
This, however, is usually where the trouble starts because the skin looks to be exactly the right shape and good to go back on but get it more than about half a rivet hole adrift, and that means a sixteenth of an inch in this case, and it just won’t go. And the best way to discover that you’re slightly off the mark is to put the internals in – that soon shows the errors as everything is pushed and pulled to line the pins up.
Loubie stepped up to lend a hand too. She’s been helping out on the boat these past few weeks but, then again, she is a Bluebird veteran as well as a Barra Babe…
As mentioned, loads of stuff has moved about with our temporary shut-down and which rib went where had to be done all over again but we’re just about ready to ask Aerospace Rob to clash the rivets in so we can stick on half a leading edge. We’re almost back to full strength now and we always have extra volunteer hours over the holidays as soon as we get fed up of all the food and drink so we’ll get cracking to make up the lost time and do you a much bigger, fuller and hopefully happier diary in January.
It remains only to thank you all for your ongoing support and, on behalf of the entire Bluebird / Barra’ project, a very Merry Christmas and a prosperous New Year.