Bill's data is a bit skewed. The Discus is probably
the most common single place glider in the U.S. I
have flight manuals for both the Discus a and b as
well as a Discus 2a and b in front of me. Per the
mfg specs both manuals list the minimum weak link as
1157 lbs.
His other claim that exceeding the 1200 lb limit will
cause the schweizer release to jam is highly suspect.
The vast majority of tows in the U.S. are done with
schweizer releases with little if any actual complaints
by tow pilots. Several years ago in soaring magazine
there was an article about a glider kiting and the
tow pilot was unable to release. However the cause
was not that the schweizer release jammed, it was the
result of a poorly installed and secured release cable
housing. The cable ties used to secure the release
cable housing to the airframe failed, which then resulted
in excessive slack in the release cable. This excessive
slack meant that the tow pilots release handle was
incapable of pulling on the schweizer release lever.

At 16:30 30 January 2007, Bill Daniels wrote:
If you check glider manufacturers weak link requirements
as listed in the
respective POH's, you will find almost all are stronger
than the maximum
lond permitted on a Schweizer tug hook. Overload a
Schweizer hook and it
jams. To me, that says that all Schweizer tug hooks
are dangerously
obsolete and should be replaced with Tost hooks - preferably
with the tow
rope retract winch.

Bill Daniels

'Chris' wrote in message
roups.com...
Our club is looking at new tow plane. The plane has
a Schweizer tow
hook with '1200 lbs max' stamped on it.
Does anybody know what that relates to?
Is this the max gross weight of the glider or max
tow tension or...?
I've tried Schweizer, but they couldn't help since
they are no longer
making tow hooks.

Thanks for any insights.

Chris