Bruce,

That's very interesting - what size cable are you using???? I would
have thought it would have been best to have a cable that was
significantly stronger than the weak link to avoid damage to the cable
and rely on the weak link to do it's job if needed.

Also, take a guess at the target indicated airspeed you see when you get
your best launches. I know what the Blanik speed limits are.

Gary

Bruce Greeff wrote:
BTIZ wrote:

our L-23 has a CG hook and does away with the bridle requirement..

maybe that's why it does not state specifically which strength weak
link to
use

BT

"Gary Emerson" wrote in message
. com...

I'm really curious what weak link people are using to winch launch
Blaniks with. If you are using the CG bridle, do you use the blue tost
weak link (in the BGA list) or a stronger one? Blue seems too weak and
wants to break frequently and under only moderate climb angles. The
L-13 manual suggests a 2000 lbs link if you are using the bridle,
however there is no similar wording in the L-23 manual.

Gary




Our club has hundreds of launches with a L13 on a blue link. Never
broken a weak link, in general the cable fails first. Our winch is a
302cu inch Ford Windsor motor, so possibly our results may not be
representative of newer more powerful winches. In still wind conditions
we get around 1500' launches, dual with a 1800m cable run. Record is
2300', solo into a 25km/h headwind.

One point, if you use a winch and do not transition progressively into
the steep climb angle something is going to break. The Blanik has
powerful elevators and with flaps out can put a huge load on the cable.
If the load is applied smoothly all you get is a descending note from
the winch, if you are rough you get a cable break as often as not.

Similarly the bridle allows the L13 to maintain a large angle of attack
at the top of the launch. This is unwise because of the load on the
glider , and will also break cables. I have seen an over enthusiastic
pilot and a strong gust combine to lift one side (jack and wheel) of our
winch right off the ground...
If you do break the cable at this point (and AOA) the probability of a
stall/spin accident is high. Pilots used to the porpoising effect of a
CG hook may inadvertently pull too hard at the top of the launch because
the bridle does not seem to do this?

Our experience is that breaks are usually caused by pilots and winch
drivers trying too hard - result is snatching or "rough" launches, and
cable breaks. Once everyone got used to the idea that a couple of feet
was not worth the regular cable repairs we have had a remarkable
decrease in cable breaks.