Winch Launch Fatality

On 26 June, 17:30, Don Johnstone wrote:
You should not necessarily point the glider at the winch, you should point
it in the direction that the cable is going to take. If there is a bow in
the cable then the glider should not point at the winch but towards the
bow so that yaw is not induced.
Of course the ideal and proper situation is that the cable runs straight
from the winch to the takeoff point when the cable direction and the winch
are both in the same direction.

The correct thing to do if a wing drops is to release the cable, semantics
maybe but can we please get the terminology right at least.

Just to illustrate the point many years a go a gliding site in the UK
winch launched on a dog leg, the winch cable changed direction halfway
down the run by being taken round a telegraph pole and the launch was
always towards the pole. The change in direction when the cable reached
the top of the pole and slipped off was interesting, the good news was
that CofG hooks were not common so the pull of the cable helped to damp
the yaw induced. I would not want to do it in a modern glider with a CofG
hook, damm dangerous I would think.

Don,

You are clearly referring to the Scottish Gliding Union at Portmoak
airfield where I have been member since 1977. We continued launching
on the dogleg ash strip for many years after that including many
gliders with C of G hooks with no problem at all (including, in my
case over those years, K6E, Diamant, Std Cirrus, Kestrel 19, Nimbus
2C). The point that is is relevant to the "where to point the glider"
issues is this: Waiting for a launch we lined up one behind the other
straight down the strip with the cable coming straight into the
glider. We were therefore pointing well to one side of the winch but
the gliders took off perfectly straight down the strip. I was never
particularly aware of any direction change during the launch.

Now that we launch straight towards the winch on the main grass parts
of the airfield we have more, not less, issues with gliders being
swung by the cable and that is because the gliders queue side by side
with a gap between them for the cable retrieve vehicle to pass
through. For each glider the cable has to be pulled over to the
glider leaving a bow in the last 50m or so of the cable. A steel
cable being pulled through grass by a our lowish power winch does
*not* pull straight as the slack is taken up and can easily swing the
glider right at the start of the ground run. When I launch I always
insist the last 50m of cable is pulled as straight as possible and not
just that the drogue chute is pulled to the front of the glider. If
that were not possible I would agree that the glider should more or
less line up with the closest 50m of cable when launching off grass.
When launching from a hard runway (or our old ash strip) this is much
less of an issue because the cable can slip sideways over the ground
so much more easily.

John Galloway