hypothetical "rebuild" question

Quote from post by JonothanF ;

“Museum aircraft are there for the mind, and the flyers are there for the spirit.”

I think the above quote is a most succinct statement on preservation of aircraft and expresses why I am so interested in historic aviation in its broadest sense. I just wish I had the wit to put it in words as well as Jonothan has!

Chris

I spent many years flogging aluminium so have some, half forgotten, knowledge.
I didn’t personally have anything to do with aircraft released materials but I did pick up a little bit.

When melting scrap ali for reuse, unless you know all the material is the same spec, and what it is, it has to be purified and then re-alloyed. The sheet, extrusions and castings from a scrap aircraft would all be totally different alloys so that’s the first problem. Secondly as somebody already mentioned, it couldn’t be used for aircraft use anyway as there couldn’t be adequate certification.

The paperwork trail for released materials is awesome, which is one of the reasons why the stuff’s 10 times the price of commercial. It used to be said that you could trace aircraft materials back to the bloke that dug the bauxite out of the ground. I’m not sure that’s totally accurate but it’s close. One reason is if a part fails that shouldn’t have done, you can trace everything else made from that batch before it fails.
As I said, this bit is based on what I picked up and although it may not be 100% accurate, the basic principles are correct.

Thanks for posting Johathan. Do feel free to stay!

Thank you James, I originally registered as I had a query from a member of the public relating to a piece of airframe, but managed to ID it before posting my request. (Turned out to be a piece of Ju88 bomb rack if you were wondering).

Interesting point re the practicality of reclaiming old aircraft alu. I wouldn’t know to be honest, but I have a feeling it would at least be economically difficult to do even if it is possible. I do understand where the thread starter was coming from, but tend to think that energies can be better spent in either maintaining the authenticity of static aircraft or in keeping the airworthy examples flying, even if they do eventually become 100% replica.

My take on the whole thorny issue of flying/non-flying is that there’s room for both. Museum aircraft are there for the mind, and the flyers are there for the spirit. If a high percentage of a flyer is historical, so much the better. I think both can serve as memoria to the dead and to veterans. But think how much less plane for your time and money you would get if you insisted on the melting down approach. I would say that I personally would rather that flying aircraft were new-builds or composites, but if they’ve been flying and been maintained as active aircraft for a time already, why not keep them flying. Unless they are one of only a handful left in the world either static or flying, in which case lets get that warbird cotton wool out!

Ok, who spiked the punch…:rolleyes:

Flood

this doesn’t mean (contrary to popular opinion amongst my friends) that I am a dinosaur!

Maybe not, but “I am Stardust, I am Golden…..”*

Dunno about you lot though 😉 :dev2:

sal****er

:giggle :rolleyes:

No re-use?

I had the same idea to build a Halifax bomber. The idea was to collect scrap metal from various wrecks and under strict supervision have the metal turned into ingots and/or sheet to be used to build a new airframe.

I heard something, many years ago (and I have no idea if it is accurate), that once aviation grade aluminium is melted down, it can’t be made avaition grade again.
Any engineers or metallurgists out there?

Thanks for posting Johathan. Do feel free to stay!

Hi everyone. On a tea break doing some enquiry research (honest) and spotted this thread. I think the idea that an aircraft is remotely ‘historic’ because it contains a certain number of molecules known to come from an historic airframe is, to be frank, right out. Any museum would regard such an aircraft as a replica, albeit with an interesting and unusual background. The aircraft has been destroyed and recreated on a molecular level, far more damaging to its ‘historicity’ (silly word) than even a complete rebuild. As a rule, I would prefer and support the conservation and display of wrecks in context, for example in a crash-site diorama.

All objects and living things are made up of ages-old particles; this doesn’t mean (contrary to popular opinion amongst my friends) that I am a dinosaur! Just as a P-51 built from scratch using 1940s metal (even all metal from a single known airframe) is *not* a 1940s aircraft.

Fully agree with Distiller’s statement

I had the same idea to build a Halifax bomber. The idea was to collect scrap metal from various wrecks and under strict supervision have the metal turned into ingots and/or sheet to be used to build a new airframe. I think it would have be feasible, but costly. You would have needed maybe 400% of the metal used in the finished product to make it viable. Obtaining the correct grade of aluminium from various sources was also another issue raised at the time.

Would it be a more accurate airframe? I think so. Knowing that “that” Halifax flying overhead consists of material from a number of named aircraft in my opinion would have made it less a replica and more original. As with most postings on this Forum the key to success is and always will be MONEY.

All

Modern CAD software has been mentioned several times in recent months, in several threads. I thought that you may be interested in some information on the subject.

Firstly CAD, it is merely a 2 dimensional, or 3 dimensional drawing tool. There are no magic buttons to press “design me a car/aeroplane/ship”, etc. A good design engineer still has to have a good brain! There are methods now where this 2D/3D information can be sent to a machine that mills/turns tooling or finished components, but generally you have to work with a toolmaker or manufacturing guy.

I use 3D CAD for my project. It is worth its weight in gold, to help piece fragmented remains together. But when you start with a complete airframe, it is probably not necessary. You cannot improve on the original significantly. The Flug Werk 190’s were drawn by a guy in Herts, and the “more efficient propellors” developed, we’re probably done only so their profiles and twist matched the selected engine properties better, and materials specified? Otherwise, why change?

Several people have asked me to produce CAD models of their wings and fuselages. This is a relatively easy thing to do, as long as key information is supplied. ie. sections, dimensions and photographs.

Cosmos/M, Solidworks, Catia … been there, done that. I at least meant more like an interpretation/optimization.

Historic aviation use of CAD/CAE software

All

Modern CAD software has been mentioned several times in recent months, in several threads. I thought that you may be interested in some information on the subject.

Firstly CAD, it is merely a 2 dimensional, or 3 dimensional drawing tool. There are no magic buttons to press “design me a car/aeroplane/ship”, etc. A good design engineer still has to have a good brain! There are methods now where this 2D/3D information can be sent to a machine that mills/turns tooling or finished components, but generally you have to work with a toolmaker or manufacturing guy.

I use 3D CAD for my project. It is worth its weight in gold, to help piece fragmented remains together. But when you start with a complete airframe, it is probably not necessary. You cannot improve on the original significantly. The Flug Werk 190’s were drawn by a guy in Herts, and the “more efficient propellors” developed, we’re probably done only so their profiles and twist matched the selected engine properties better, and materials specified? Otherwise, why change?

Several people have asked me to produce CAD models of their wings and fuselages. This is a relatively easy thing to do, as long as key information is supplied. ie. sections, dimensions and photographs.

So, aircraft built in the late 40s and 50 from recycled aluminium are actually WWII veterans waiting to be rebuilt…?;)

Flood

Similar questions come up time and again in classic car circles.
I think what counts is the history of the specific plane.
Re-building an aircraft is not “historic”, it is “retro”. That might be fun, but Mr. Bigbucks might have even more fun dragging old plans through a FEM/CAE software and have it built from the stretch as pure retro. Think what you could do to a Spitfire with todays aerodynamics, materials and electronics! Look what Flugwerk does; and they don’t optimize their planes.

Again likening to classic cars: You can build every pre-WW2 car from scratch for about 500k Euro. The reason why Bugattis, Lagonds, Delahayes, etc yield millions of Euro in auctions is the knowledge of their history and the way we feel about the real and rare things. (Of course there is also the aspect of investment and speculation.)

I think an aircraft can be considered “historically valuable”, as long as a high percentage of structral parts plus the engine is original and from one and the same aircraft. Everything else is just reinactment or even retro.

Simple answer – no it would not be more original than a ‘new build’ P-51.

Complex answer – By smelting down an original airframe, with all the widgets and knobs etc removed, you are still only looking at perhaps 50% of a complete aeroplane. So you will be smelting 70% of 50 %, i.e. 35% of a complete aeroplane. Assuming you can find someone to reconstitute a small batch into sheet material, you will then lose perhaps a third of the sheets in off cuts and swarf, so will be left with less than 25% ‘original molecules’

The so called new build P-51’s still use a lot of surplus material from wartime production, as well as a lot of new build structure, so do have a degree of originality. The structure in your new aircraft, albeit partly made from reformed Aluminium is still new structure, and was not made on original jigs and formers.

I wonder how many molecules of original world war 2 aluminium are still flying in modern aircraft today. I suspect that most airliners could lay claim to having been active over the Ruhr, at least in a small molecule percentage!

Bruce