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Old July 5th 09, 02:38 AM posted to rec.aviation.soaring
bildan
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Posts: 646
Default SAFE Winch Launching

On Jul 4, 5:15*pm, Derek Copeland wrote:
To all my friends in the United States of America.

You may have got the impression from some recent correspondence on this
site that winch launchings is about as risky as bungey jumping or joining
a Kamikaze squadron!

In fact we do many tens of thousands, if not hundreds of thousands, of
winch launches in Europe with only the very occasional accident. Even the
ones we do have are largely avoidable.

Most of the serious winch launching accidents come into the following
categories:

1) Ground loop or cartwheel after catching a wingtip on the ground.
2) Flick spin due to over-rotating after lift off.
3) Stall/spin after a cable break or other launch failure.

These can be avoided respectively by:

a) Pulling the cable release knob if a wing drops.
b) Monitoring the airspeed and controlling the rate of rotation to not
more than 10 degrees/second.
c) Lowering the nose to the recovery attitude and regaining a safe
airspeed before attempting any further manoeuvres. Also learning the most
suitable options for landing safely from various heights.

Things happen much more quickly during a winch launch than they do during
an aerotow, so you do need to engage your brain before you start moving,
not halfway up the launch.

There is starting to be more interest in winch launching in the States,
due to rising fuel and maintenance costs for tug aircraft. However I have
found it somewhat disappointing that some of the leading US protagonists
seem to want to ignore any advice from European clubs and winch builders,
who have a wealth of experience in this method. It's the 'good ol' US
of A always knows best' syndrome. As a result you have already suffered a
fatality and two serious injuries this year from a fraction of the number
of launches that we would do in Europe in the same period.

You already have the most of the basics for winch launching in the US. You
have many vehicles fitted with large and powerful V8 engines and good
automatic gearboxes that can be cannibalised to make decent winches.
Please note that you must disable any kick down arrangement on the
automatic gearboxes. If you join a Yahoo group called 'Winch Design' you
will find a document written by the BGA winching advisor called 'Proven UK
specification' which gives you most of the information needed to build a
good winch. You don't need very fancy and expensive, but as yet unproven,
diesel-hydraulic or electric winches that the above protagonists seem to
think are essential.

Derek Copeland


Written by someone who thinks British automobiles with Lucas electrics
are reliable transportation.