How's the Composites holding up?

"Capt. Geoffrey Thorpe" The Sea Hawk at wow way d0t com wrote in message
news:AvWdnQSRlpgvFUPZnZ2dnUVZ_sWdnZ2d@wideopenwest .com...
"Jeff" jfranks1971 minus wrote in message
...
Many moons ago, (early to mid-eighties), I was reading quite a bit of
material about the "new" composite airplane revolution and how different
life was going to be with the ability to make planes from the fantastic
substance. The main concern from the "experts" in many of these articles
was that they didn't know how the composite materials would hold up over
time. It seems that many folks thought that after years of sun exposure
and/or heat/freeze cycles, the materials might become brittle or degrade
in strength.

Now, obviously, I realize that there aren't many Long-EZ's falling out of
the sky and that many of the new methods are more advanced than the first
tries, but I was wondering how 25+ years has faired on these planes?
Was this fear just a crazy thought or was there some validity to the
concern that has reared its ugly head now that we've had some time to
look back?


You can get $20,000 for a glass glider built in the '70's.

Does that answer your question?

http://www.wingsandwheels.com/wantads1.htm

--
Geoff
The Sea Hawk at Wow Way d0t Com
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When immigration is outlawed, only outlaws will immigrate.


Yes, it now appears that composite gliders will outlast metal ones. The
gelcoat will degrade but the underlying structure seems to last forever.

Yes, it now appears that composite gliders will outlast metal ones. The
gelcoat will degrade but the underlying structure seems to last forever.


be careful, guys; you have to distinguish:

one thing is the gelcoat. it protects the fiberglass (or carbon) structure
underneath from UV light which harms the epoxy resin. regular gelcoat is
not resistant to UV light forever; cracks in the gelcoat work their way
into the laminate. a while ago, i had to repair the outer layer of glass of
a fiberglass wing just because of that. the problem appears especially when
the gelcoat (or filler, when using automotive paint) is very thick, making
the surface or paint layer too stiff to follow the fiberglass' strains,
which results in cracks.

another thing is the structure itself. as mentioned above, it's strength can
be affected e.g. by UV light and it has to be protected against. if this
protection is maintained, and the structure had been designed and
calculated in a correct way, fatigue is not really an issue, and the
material's strength remains. aluminum is much worse...


uli