Hi Paul,

I was on the thinking seat, and remembered something I read about the
deterioration or break down of carbon fiber race car tubs. I do not know
if
this was a result of the material failing due to age or from the abusive
environment of a race car. The stiff suspension and repetitive shock
loading
from bumps on the track may be the cause. Or is it a result of exposure to
UV
light and or dark paints?

How would this relate to carbon fiber aircraft construction? I know that
composite construction is sensitive to color from heat build up from dark
paints. Turbulence and hard landings will put a stress into the structure.
All
materials will fail eventually due to applied stresses. That was the cause
of
the Air Hawaii failure. Part of the solution is the design of attachment
points to dissipate applied stresses to reduce them safely.

I also saw recently on How Stuff is Made about the construction of
Kenworth
trucks and also the new Lotus car. The both bond parts of the cab (truck)
and
chassis (Lotus) together.  The Lotus uses extruded aluminum to make the
chassis. The epoxy is applied and the parts are held together, until they
can
be cured for a couple of hours in an oven. Does the curing enable the
proper
adhesion or is there a chemical etch like you recommend also used? This
could
make for very clean aluminum skins. You would not have the stress points
that
you have with rivets and stresses would be dissipated over a large area.

Dale Davies

I have no knowledge of that. There are some fiberglass boats still
around after 60 years. It does not appear to fatigue and crack like metal.
When we were racing fiberglass tubs back in the 1960's they never seemed
to develop any problems.

Paul Lamar

My guess would be that they are built as light as possible to the nth degree
and that there is not enough strength for longevity.
A friend who is an experienced racing sailor (not sure that is the right
term) has a boat that was used for hardcore cruising/racing. It has a lot of
bent bits on it apparently from the rigors of its racing past. As I
remember the 12m race hulls are unbelievably big dollar hulls, similar to
high performance sailplanes, yet after a few seasons the hulls can be bought
dirt cheap, they just don't last.

John