John is correct in his points. To add just a bit of detail to the
current contruction technique that I'm aware of. In the cockpit, SH
uses a weave that looks to be about 50/50 carbon fiber woven with
Kevlar. The plan is that the carbon fibre gives very high strength and
the Kevlar gives good toughness so that if the strength of the carbon is
exceeded that the kevlar will hold things together. I'd be guessing,
since I haven't actually seen it, but I wouldn't be surprised if all the
major manufacturers were using this same materal in the cockpit areas.

John Galloway wrote:
And Schempp-Hirth gliders for many years. Apart fom
Kevlar material issues the modern German cockpits all
have structural features to improving impact performance.

Having had 2 syndicate partner's over the years who
had major cockpit destroying impacts in our all glass-fibre
gliders I think that the safety concerns are very real.

To design, manufacture, prove and get the approvals
for retrospective structural modifications to the cockpit
might be very difficult and would likely cost more
to an individual than changing gliders.

John Galloway



At 09:30 19 January 2005, J.A.M. wrote:

I think that the ASW-24 and -28 (maybe the -27 as well)
are built with a
kevlar layer in the cockpit. It does not improve strenght,
but provides
splinter protection when the cockpit shatters. Fiberglass
when broken is
extremely sharp, so the kevlar makes the shell stay
together and not
splinter.
I may be wrong, so anyone with more knowledge feel
free to correct me!

Good flights (winters almost over...)
Jose M.

'Stewart Kissel' escribió en el
mensaje ...

After seeing first hand the eggshell strength properties
of glass cockpits when they hit objects, I have been
thinking about how much protection I don't have between
my spine and terra-firma.

I have the astronaut foam, and otherwise it is just
the seatpan and glass. I was chatting with my A+P
about this while we had the seatpan out during my
annual.

Has anyone contemplated and/or added kevlar to their
cockpits? Or is this just a nutty idea? I assume
their would be a weight and balance issue, and also
determining if the layup would in fact to any good.
Comments?