As most people who browse this forum will know,one of the main considerations when it comes to restoring a machine to flight is the availability of engines and servicable spares.It’s been said that certain Merlin components are becoming increasingly scarce,and that serviceable parts for some engines (eg early Bristol Hercules) are almost non existant.
I’ve heard rumblings on the grapevine about the possibility of building new Merlin spares (even things like the entire engine block),but things have gone ominously quiet.Is it on grounds of cost and/or legal considerations?I’ve recently been in touch with a guy in the US who’s purchased a Fairey Swordfish,and he is embarking on an airworthy restoration of the aircraft with a small workforce in his own workshops.When I asked what spares availability was like for the Bristol Pegasus,he said that they were none too plentiful,but that it didn’t matter as he had the tooling and skills to reproduce almost any part which might be needed,even some of the more complex castings,eg cylinder barrels.I was wondering what the official stance on this kind of thing is,and whether the same could be done over here in the UK.
By: Yak 11 Fan - 15th December 2003 at 08:41
Which is fine if you are building an engine in the States but not here, however the massive grey area (as has already been pointed out) is that you can have an American built engine in the UK, but who then knows what is lurking inside.
By: Flat 12x2 - 15th December 2003 at 01:08
From the Vintage V12 site Vintage V-12: Restoring Merlins
When we asked about the availability of parts for these old war-horses, both Kim and Jose indicated that it’s really no problem. Some parts, like pistons, are now back in limited production. Others, if not available, can be specially cast or machined by some shops.
By: Hamtech - 14th December 2003 at 12:52
The Americans fly these aircraft in an “experimental” class. Down here and its probably the same in the UK for now we fly them under an “approval to fly”.
With that in mind these machines will not be subject to the same regulations as “real” aircraft which are allocated a certificate of airworthiness, but still hopefully kept under a close eye by the CAA / CASA / FAA or duly appointed representatives.
As you can see with the Reno air races the experimental class is taken to the extreme with total loss cooling systems – the P-51 “Stiletto” with no ventral scoop, build up of Merlins using a mix and match of parts, ie Packard parts mixed with RR parts etc. etc.
Even ground engineers don’t use their normal licence on “non CofA” aircraft, they are issued a “Maintenance Approval” to certify these machines.
Jump in if I’ve got it wrong chaps 🙂
By: dhfan - 14th December 2003 at 01:16
Would seem a bit daft but the CAA does move in mysterious ways at times.
There’s half a Merlin crankshaft forging tool in the Sheffield Industrial Museum. I wonder if they’ve got the other half.
By: Arabella-Cox - 13th December 2003 at 22:28
Yak, I’m intrigued. I was under the impression that Air Racing events such as Reno had a tendency to result in wrecked engines, and therefore a need for new build Merlin cases and internals, which have been required in such quantities as to make tooling and production runs economically viable, and that these new build parts have been responsible for keeping various warbirds airworthy?
Presumably if that’s the case, they must be certified at least by the FAA, but your post implies that the CAA aren’t on board.
So in that case, what happens if a warbird from the US comes across the pond with FAA-licenced new bits in the lump? Do the CAA allow any dispensation, or do such aircraft have to be re-fitted with reworked (and therefore used) parts? Seems a bit backwards to me if that’s the case.
By: Yak 11 Fan - 13th December 2003 at 21:49
In the UK at least all you can do is repair original parts you can’t make new. The CAA require the support of the original manufacturer for new components, in this case Rolls Royce, who these days aren’t interested in supporting 60 year old engines.
By: Eddie - 13th December 2003 at 21:25
I know that some new cylinder block patterns and I think crankcase patterns exist for Merlin engines – the technology is certainly there (and no doubt the casting quality would be better) but the investment required in patterns is huge – we’re talking tens of thousands for these patterns. As a brand new crated Merlin can be bought for less than that, it’s not economical to spend that kind of money.
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December 13, 2003 at 9:08 pm