Eric Greenwell wrote in message ...
Chip Bearden wrote:
The Libelle 301 and 201 did it right way back in the mid to late '60s:
an over-center "wrench" that used metal pins embedded in the top of
the wing spars to lever the wings together the last few centimeters.
Sometimes "progress" takes us in the wrong direction.

The lever was almost a necessity, due to the multiple pins on the ends
of the spars that had fit into the sockets on the wing. What made the
system work well wasn't so much the lever as the access: without a
turtle deck, you could see the pins' alignment and guide the person on
the wing tip.

It might take more careful alignment to get the pins into a Schleicher
glider, but at least pushing in the second wing doesn't push out the
first one. If you like using a tool, a Schliecher glider can have it's
wings pulled together just as quickly and easily as the Libelle with
Cobra's eccentric wing pin tool. It does take an extra moment to put in
two pins instead of one, but it's better than fighting multiple spar end
pins that you can't see.

Good point. Access to the Libelle pins was superb without the fuselage
structure over the wings that modern gliders have today. I agree that
the wrench was a near necessity with all the pins and sockets. For
those who haven't assembled one: each spar end--a forked double spar
on one wing and a single spar tongue on the other wing--has a pin that
fits into a socket in the opposite wing.

On the other hand, I recall assembling my father's Diamant HBV, the
15M version that used Libelle 301 wings with a more conventional
fuselage design (i.e., the area above the wing spars was enclosed).
Once we learned a few tricks, that became straightforward...so long as
we had the wrench.

I also recall that a few other early fiberglass gliders had similar
wrenches. Possibly even the later Diamants (16.5 and 18m versions)
which used a wing pin design a little more similar to today's types.

The Cobra eccentric wing pin tool sounds like an interesting
alternative to the over-center wrench.

Chip Bearden
ASW 24 "JB"