Which Tow Vehicle

Dan G wrote:
Research has shown that only a modest - less than 50 cm - extension of
the nose is sufficient to absorb enough energy that a safety cell in a
glider can be effective up to at least 25 g:

http://www.ostiv.fai.org/CkptRoeg.pdf

A very interesting report! I'm pleased to see cockpit design has
progressed this much.

As has been pointed out by others in this thread, Lange have used this
research and so developed the extended collapsing nose-cone of the
Antares.

I was impressed by the design before; now, even more so.

On Oct 13, 5:32 pm, Eric Greenwell wrote:
It looks like a good design; still, an additional 4" over a "normal"
fuselage is not much compared to the several feet of crush zone
available in an automobile.

The human body can easily survive 45 g with a good harness:

http://csel.eng.ohio-state.edu/voshell/gforce.pdf

So only a few tens of centimetres are required to reduce the
acceleration in a glider crash to survivable levels.

This was surprising to me. Also surprising was the statistic that 76% of
the accidents have impacts less 101 kph. I would have guessed much
higher, and I know much higher impact speeds were part of the "several
feet of crush zone" discussion that took place about 15+ years ago.

Is it intended that the [Antares] cockpit function in
the "safety cell" manner that Dan G was describing...?

Yes:

http://www.lange-flugzeugbau.com/htm...0e/safety.html

I wish there indpendent tests of glider crash protection that were
released to the public, because it is very difficult for us to determine
the effectiveness of a design, especially new designs that have not had
any crashes yet.

There has been lots, see the link I posted above and also the DG
website for some overviews. Tony Head first conducted crash testing in
1988 and did lots more. TUV Rhineland did testing throughout the
1990s.

And also by a group at MIT:

R. John Hannsman, Edward F. Crawley, and Karl-Peter Kampf, Experimental
investigation of the Crash-Worthiness of Scaled Composite Sailplane
Fuselages, Technical Soaring, volume 14, number 4, 1990, page 111

But, what I was wishing for was standardized testing of production
sailplanes, similar to what is done for automobiles. An expensive wish,
I know, but perhaps soon standardized computer calculations could
replace full scale testing sufficiently well to make safety comparisons.

--
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