Just to clear some things up:
The Antares family of gliders has been designed with
a safety cell and energy absorbing nosecone. In order
to facilitate this, the cockpit was extended forward
at approximately zero aerodynamic loss. The whole cockpit
is using a special carbon-carbon technology (no kevlar
or dyneema), and was designed mainly by a F1 crash
structure designer. The safety cell has been design
to fail only after there is nothing left to save inside
(due to extreme g-loads).

Fitting the lower part of the pilot into the crumble-zone
is, in my personal opinion, not the best of ideas,
as damage to the feet tend to take extremely long to
heal.

Andor



At 02:18 13 October 2007, Eric Greenwell wrote:
Dan G wrote:
On Oct 11, 3:41 pm, Eric Greenwell wrote:
Dan G wrote:

Crash-worthiness and energy absorbtion is ENTIRELY
down to design, not

material.
The major glider manufacturers don't agree with this:
take look at the
cockpit of a Schleicher glider, for example, and see
how little of it is
carbon fiber. Aramids and glass fiber absorb energy
better than carbon
fiber, and so a designer will use them if it is possible.

Didn't I say it's design, not material? :-) However
Shleicher do
actually use carbon fibre reinforcements on at least
some of their
cockpits - check their website:

http://www.alexander-schleicher.de/p...sg29_main_e.ht
m

All Schleicher gliders, beginning with the ASW 24,
use carbon fiber
rails on the cockpit sill, but even on the ASG 29,
most of the cockpit
structure is still glass fiber and aramid composite.
Gerhard Waibel had
an excellent article describing the design of the ASW
24 cockpit,
considered the first of the modern 'safety cockpits',
in Soaring
Magazine about 20 years ago, and also more recent articles
in Technical
Soaring. Those articles can explain the design of an
improved cockpit
much better than I can here.


Lange might do too - they say they use 'F1 materials'
for the cockpit
of the Antares.

The underlying point is that you want the safety cell
- whether car,
glider or even train cab - to be extremely strong
to resist collapse,
with deformable parts elsewhere to absorb energy and
hence lower peak
G on the occupant.

To the contrary, Schleicher and the others have chosen
not to use a
'safety cell' design. The nose would have to extend
several feet beyond
were it does now to have sufficient crush distance,
and they do not
believe pilots will buy such a glider.

--
Eric Greenwell - Washington State, USA
* Change 'netto' to 'net' to email me directly
* 'Transponders in Sailplanes' http://tinyurl.com/y739x4
* 'A Guide to Self-launching Sailplane Operation' at
www.motorglider.org