On Jan 25, 7:47*pm, Andreas Maurer wrote:
On Tue, 25 Jan 2011 16:48:29 -0800 (PST), Andy
wrote:



As a Schleicher driver I'm interested to know what failed. * How did
the wings separate from the fuselage but remain together? *Did all the
lift pins fail, or did the lift pin sockets in the wing roots fail, or
was there somehow sufficient bending of the spar that the lift pins
detached without the pins or sockets failing. *Maybe the whole lift
pin carry through structure detached from the fuselage but isn't it
attached to the landing gear?

Hi Andy,

Schleicher gliders have a notorious weak point: The bushings that hold
the lift pins are a little bit too short and not fixed in the shear
force tube - there have been a number of accidents where they were
twisted and ripped out of the shear force tube instead of keeping the
wing attached. (I hope I got the technical terms halfways correctly).

However, I'm not aware of such a thing happening inflight, but it
happened a couple of times after a wing hit a tree and an extremely
hard impact. I'm pretty sure *that strong wing flutter exhibits forces
that are sufficient.

In Schleicher gliders, the structure that carries the wing is not
directly attached to the landing gear (as ist is the case with most
Schempp-Hirth gliders).

One thing should be mentioned: I have the impression that the
Schleicher design is - despite the problem with the bushings - one of
the strongest - in case of a crash the wings of Schleicher gliders
stay attached to the fuselage comparably often.

Andreas

Thanks for that information Andreas.

Andy