On Jan 25, 7:48*pm, Andy wrote:
On Jan 25, 8:05*am, BruceGreeff wrote:

I have seen an ASW20 where the wings departed the fuselage together-
ripping the main spar out of the fuselage.

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?

I'd always assumed the spar would break before any of that could
happen but I know the 20 spar is more flexible than some.

Andy

Interesting about the mode of structural failure on sailplanes. To
the defense of BRS...From what I learned in my research for possiblly
installing a BRS system into my homebuilt ...the BRS guys do a lot of
research and testing. It is not so simple as just hooking the
parachute onto some convenient spot on the aircraft. I have not seen
the details on the BRS set up for sailplanes, but on my airplane I
had originally expected that the parachute would be connected to the
center section of the top wing spar......I soon learned that this was
a bad idea and not how it is done. The BRS design called for kevlar
straps under the pilot and passenger section of the fuselage......In
theory, the wings could fall off, the tail could fall off ,the engine
could fall off and the passenger section could be severly damaged, and
still return the occupants to earth relatively unharmed.

I would not expect to see a recovery chute attached to the spars, or
spar stubs in a glider.....rather somehow strapping under the
passenger area of the cockpit.

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