Costs of composites

"Dan, U.S. Air Force, retired" wrote in message
news:%Ub0e.5735$%d7.4545@lakeread03...
COLIN LAMB wrote:

I built my own kayak and canoe and went through the same questions.
Because
you often need to carry the kayak and canoe, weight is a big factor.

I got most of my answers at Tap Plastics. Any local plastics outlet
will
have the various cloths that would be used, together with books and
clerks
who know the various materials.

RVs seems to be popping up everywhere, and that tends to diminish the
need
to learn about various materials. So, you may run into a campaign for
you
to build an RV if you visit an EAA chapter.

So, visit the kayak websites and any local kayak manufacturers. You
should
be able to find a chart of various materials used in constructing
kayaks,
and you can visit the websites to see the hype for that material (do not
necessarily believe all of it. Kayaks going through white water need to
be
tough.

73, K7FM


I would think it's a different kind of toughness what with bouncing off
of boulders and all.

Dan, U.S. Air Force, retired

I suspect the same; and would expect Kevlar to be a material of choice
despite, or possibly because of, its tendency to extrude out of the
encapsulating resin. That may be part of its toughness.

This information is now twenty years out of date, but a formaer offshore
boat racer once told me that a Kevlar hull was about ready for the dumpster
at the end of a season. Apparently, repeated loading separates the fiber
from
the resin.

Peter

"I would think it's a different kind of toughness what with bouncing off of
boulders and all."

There is no doubt some differences, however boat builders face similar
problems to aircraft builders. Being beat up by the ocean currents is not a
lot different than being beat up by the air currents. One of the local
sailplane pilots built the US sailboat that just sailed around the world
single-handed. I understand it was a mixture of wood and composites. There
was no failure. I understand his construction method was unique.

Colin

If you are looking for tips on state-of-the-art composite structures, then
look at sailplanes. With aspect ratios exceeding 30:1 yet still yielding
10G structures, they are pushing the limit of what is possible with the hand
lay up processes.

Take a look at: http://www.leichtwerk.de/eta/images/...arzinzik10.jpg
Or: http://www.leichtwerk.de/eta/images/...arzinzik08.jpg

The L/D is reported to be in excess of 75:1

bildan


"COLIN LAMB" wrote in message
ink.net...
"I would think it's a different kind of toughness what with bouncing off
of
boulders and all."

There is no doubt some differences, however boat builders face similar
problems to aircraft builders. Being beat up by the ocean currents is not
a
lot different than being beat up by the air currents. One of the local
sailplane pilots built the US sailboat that just sailed around the world
single-handed. I understand it was a mixture of wood and composites.
There
was no failure. I understand his construction method was unique.

Colin