Tue Jan 08, 2013 3:19 pm
#1133799
Rob P wrote:Ah... Mrs Grace's favourite.
Fails to provider any answer to the OP question though.petestorey wrote: ... why can't you simply (ahem) take the original blueprints, and build a new one from them?
Rob P
Here's an example, in my day job I've been worrying this last month about a fuel system problem with one-off BAe-146 variant. Nothing apparently insoluble, some deficiencies in the fuel hose and connections, causing some leaks, that weren't then venting to the outside of the aeroplane properly. Easy you'd have thought - it's been okay for the last umpty-ump years, just replace the hoses and fasteners and all will be fine.
Except that the hoses came off a late model BAC 1-11, and are no longer manufactured. Worse, they're in a material which nobody anywhere in the world manufactures any more, and of a diameter that nobody manufactures any more either.
Change those, and we've changed the design, and have to start re-making, redesigning, and recertifying the fuel tank attachments as well of-course. And suddenly an apparently simple fuel leak will cost several tens of thousnads to fix.
Now extend that to a Spitfire. You may well have a set of blueprints, and if you're lucky designs for the several thousand modifications and production modifications which were also made to it. But almost certainly the airframe will have been made of aluminium alloys that no longer are made, because they've been "improved", the fuel hoses will be of gauges and materials no longer available, the instruments are no longer manufactured, the sutton harness was a dodgy item at the best of times, so you'll want to change that for something more modern, the original WW2 parachutes will no longer exist, so you'll need to use something more modern, which will mean modifying the seats. Almost certainly some of the lubricants will be based upon whale-oil, so you'll need to specify something different, and raise a design variation to approve that....
... so basically building an identical replica from plans of a vintage aeroplane (or even the extended range fuel system for my BAe-146 which is only 30ish years old) is impossible. Any replica is substantially a design exercise, you can't avoid it.
G
I am Spartacus, and so is my co-pilot.