At 17:23 27 July 2009, Peter Scholz wrote:
Don Johnstone wrote:
...
If you were to say that measuring the tension at the glider release
and
using telemetry to pass this information to the winch then that might
indeed work, however if you were going to the trouble of doing that
you
might as well send useful information, like the airspeed of the
glider,
so
the winch driver could maintain a constant speed.
Cable tension during a winch launch has sod all to do with anything
except
as an indicator to the winch driver of possible over or underspeed. It
is
the speed which is of relevance and importance.


We have recently tested the Launch Assistent that is sold by Skylaunch,
http://www.skylaunchuk.com/index.htm
and have found that is can be (as the name indicates) an *assistant* to
the winch driver to help him/her judge the speed of the plane. It helps
escpecially unexperienced winch drivers, or in adverse conditions like
shearing winds within the launch.

After 20 years of experience as a winch driver and winch instructor
(Tost winch) I still believe a well instructed and experienced winch
driver (and all winch drivers should have a certain minimum of launches
per year) is able to judge and control the launch as good (or even
better) than any automated (tension-controlled) system, that in the end
also relies on the correct behavior of the pilot instead of the winch
driver.

--
Peter Scholz
ASW 24 JEB


Well, there you have it, problem solved by superior and relevant British
engineering and at reasonable cost.
Tension controlled winches are obsolete already as we have jumped a
stage.
Any move to automatic winch driving would be a big big mistake, a good,
well trained winch driver is the best way of ensuring safety.
Automatic takeoff, automatic landing, automatic crash.