If Skylaunches winches are supposed (by Bill Daniels) to be so bad, how
come I got 55knots on the nail (perfect speed) for every winch launch I
did on a Skylaunch today while instructing in a K13 in quite windy, rough
and gusty conditions? No oscillations, no over or underspeeds, no weak
link breaks and no unwanted gear changes.

Derek Copeland


At 21:45 12 July 2009, David Chapman wrote:
I mis typed, ..
the winch is relevant to a good launch, but the pilot is responsible for
the safety,


At 21:30 12 July 2009, David Chapman wrote:
I would love to fly a tension controlled winch we were launhing today
in
to strong head winds increasing rapidly part way up the launch. I can
imagine it is better, but I am not an expert.

Winch safety is mostly in the hands of the pilot, the winch is not
relevant to a good launch, but the trained pilot must be able to react
to
any scenario.

But other nonsense posted here . please help me, ...

A standard car auto gearbox has some magic power to automatically
adjust
the torque to the car wheels on reaching a hill, without changing gear,
road speed or engine setting? What magic is that?

David.


At 18:45 12 July 2009, Andreas Maurer wrote:
On Sun, 12 Jul 2009 12:45:08 +0200, Marian Aldenhövel
wrote:


... yet thousands of clubs in Europe with much, much more winch
experience than any club in the US don't see the need for such a
system.

Some do.

Indceed some do - but very, very few.
If there really was an urgent need we'd have more than a couple of
such winches in Europe by now, don't you agree?

When I was trained as a winch driver I was taught to judge cable
tension

and use that as the input parameter to the control loop. The only way
of

doing that without special sensors is to look at the cable sag. Works

during the main portion of the launch, but is not very accurate of
course.

But sufficiently accurate, isn't it?
Contrary to the believe of some people here it doesn't matter if the
speed during the winch launch is 5 kts faster or slower (although the
perfect speed certainly increases launch height).

I think if the winch, or winch driver, has the means to control
tension

and the pilot controls airspeed winch launches become more efficient
and

even safer. Reports suggest that, I have no experience of my own.

Efficiency? Definitely.
Safety? I doubt it.
I havent't been able to find even one accident report that was caused
by inappropriate power setting by the winch driver, yet there are
comparably many accidents caused by rope breaks or complete power
losses of the winch - things that cannot be prevented by tension
controlled speed.


Also you would propably get much more consistent launch performance
across different conditions and much more important, different
drivers.


Indeed. Nice to have.

Today we get launches like being shot from a carrier deck and the
lumbering wingrunner-testing type all in the same day depending on
who

is manning the winch. The first launches of the day, or after a
driver

swap, or when conditions change would no longer need to be different
than those by a well-adapted driver.

Typical problem of winch driver training. Once we started to re-train
our winch drivers who had problem scontroling the speed, we got rid of
this problem.


Viele Grüße
Andreas