Overspeeding on winch launches

On Fri, 10 Nov 2017 14:46:00 -0800, john firth wrote:

On Monday, November 6, 2017 at 7:48:16 AM UTC-5, Dan Schmitz wrote:
I'm wondering what the consequences of overspeeding on winch launches
are? I understand that it places stress on the airframe, but to what
extent?

I find it near impossible to control the airspeed on the top third of a
launch and have found myself over speeding the placarded max. speed by
5 - 10 knots a few times despite signalling to the winch driver.

Should I be taking the approach of releasing at 2/3 of typical launch
height (e.g. 700 - 800 foot) if my airspeed isn't under control at this
point?

Thanks in advance

I have seen a cable tension display in a modern winch in the UK.
It showed the proper tension for each glider type. It would seem to be
the right way to optimise the launch.

All Skylaunch winches have a sort of analoge computer: you input the
glider type and windspeed (our winches have an anemometer on the roof)
and that sets a stop at the optimal speed. The driver is still responsable
for initial acceleration and can, IIRC, override the stop, but it
generally gives a pretty consistent launch.

They'll also rebuild almost any other winch (we, CGC, have a Skylaunch
and a Tost they rebuilt) or supply a kit for clubs that want to do their
own work, but they can all have the analogue computer thingy installed.

The glider ASI telemetry is an optional extra that lets the wings driver
see the glider's actual airspeed.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |