From: cdorrough@nortonconsultants.com
wrote in message
news:1102948546.595364.120190@z14g2000cwz.googlegroups.com...
>
> Cameron Dorrough wrote:
>
> > Airliners are mostly plastic these days (ie.
> > kevlar and carbon composites) -
> > with a few bits of aluminium here and there.
>
> Large airliners are still primarily aluminum. For example, the upcoming
> A380 giant is setting a record by being 25% composites by weight.
By *weight*?? Have a think about that statement for a sec...
The difference in weight between, say, a B777 rudder (all composite except
for the Al center spar with the hinges on it) and a, smaller, B747 rudder
(all aluminium) is that 2 people can carry the first one and you need a
crane for the second.
By volume might be a better comparison - that's closer to 50% on the B777
and a lot more on the A380! :-)
> > Metal is sooooo retro!! ;-)
>
> Such was my thought when I specialized in composites and ceramics in
> college. My first job was for a Navy subcontractor. I eagerly dove into
> projects looking for the advanced materials in use.
>
> Composites? Nope, steel.
> Titanium? Nope, steel.
> Ceramics? Nope, steel.
> Stainless steels? Nope, normal steels.
>
> Steel and aluminum are not retreating from use rapidly. They sit in
> regions of materials properties where their combination of strength,
> durability, weight, and cost will keep them in use for a long time.
True, true - I was being more than a little tongue-in-cheek, but modern
composites will (hopefully) minimise their use eventually.
eg. a typical aircraft kevlar-honeycomb carbon-fibre sandwich is many times
stronger, more durable, lighter and maybe not yet cheaper than sheet steel
(but easier to fabricate into complex shapes) - but it just can't take the
heat that steel can - yet. :-)
Cameron:-)
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