On Aug 13, 11:35*am, Frank Whiteley wrote:
On Aug 13, 10:56*am, Andy wrote:

On Aug 13, 8:30*am, bildan wrote:

Always use the EXACT weak link specified in the manual. *If a glider's
manual doesn't specify a winch launch weak link - you're going to be a
test pilot if you winch it.

What would be the consequence of using a link say 10% weaker than that
specified? *If I know the link is weaker I can fly a less agressive
climb profile and accept that I will get a lower launch altitude. *If
I forget and climb agressively the link will break - so what?

Andy

I've had experience as a winch driver with gliders using weaker links
resulting in frequent breakage. *In that case I would suggest the
pilot insisting on using the weaker link be held accountable for the
cost of broken link and any lost rigging. *Links are $7 (x4 in this
case) and I'm still looking for a missing strop, shackle, and ring set
($100). *Two went missing on a single day, with one having since been
recovered. *A few years ago a strop vanished and was found 4.5 years
later.

There are recommendations that if the correct value isn't specified or
known to use 1.3 x MAUW. *This is one reference to that formulahttp://tinyurl.com/258ba3j

Frank Whiteley

Again, Frank has provided a good analysis. Again I will add a few
points.

As frank says, a weaker than specified link will muck up the operation
when it breaks.

You really don't want it to break since you will then have to deal
with a launch failure - usually as you load the rope while rotating
into the climb. This, is NOT good.

If your glider was certified with an Approved Flight Manual, as all
JAR-22 gliders are, FAR's require you to operate in compliance with
that manual. That includes using the correct weak link - usually
specified to a + or - 10% tolerance. Incidentally, that also applies
to aero tow. The old 80-200% rule only applies to gliders without an
AFM. (i.e.Schweizers)

If you are being launched with one of the new Automatic Tension
Control winches, you must control your airspeed with pitch.
Attempting to climb at a lower angle will result in an over speed
condition.

The bottom line is you have no choice in weak links - you must use the
one specified in the manual.