Wing Launch - Can it pull your wings off?

The debate on the merits and technicalities of winch launching will
rage on ad infinitum as it has for years in the winch newsgroups.
However, in terms of winch safety the statistics for the UK and
Germany are very different. Winch launching on the Continent shows a
much lower accident rate than the British experience. In other cases a
mishandling of statistics paints an out-of-focus picture. For example
an article published in Soaring magazine a while back quoted
statistics from a very small sample group to make a point about winch
safety. The article was very much off-base and was a poor piece of
work based on insufficient data. *The German study, however, does
appropriately apply statistical analysis to an appropriate sample
size.

Glad you brought this up, I also didn't like that article. My main
problem was less the sample data size, but rather the timeframe it
represented. It lumps all the statistics going back to the 60s into
single figures when it should really be separated into at least 2 or 3
different 'eras' for that same timeframe, when various gliding
authorities and groups identified common problems and implemented
standardized solutions that were game changers. Also, modern winches
are orders of magnitude more powerful and more importantly quite
controllable. That combined with material advances (UHMW etc) further
separate modern winching from it's roots.

Modern winching is pretty much a science and has come a long way since
the 60s so it does not do the soaring community (US at least...) a
favor to combine it all into single raw statistics cause it paints a
negative biased picture based on irrelevant data. It would be like
combining accident data from the era before seatbelts and airbags with
modern car accident statistical data, and then using that to form
statistics/articles to help potential future drivers decide how safe
cars are.

-Paul

On Sun, 15 Aug 2010 10:29:49 -0700 (PDT), sisu1a
wrote:


Modern winching is pretty much a science and has come a long way since
the 60s so it does not do the soaring community (US at least...) a
favor to combine it all into single raw statistics cause it paints a
negative biased picture based on irrelevant data.


Hmmm... I beg to differ.
Modern winching has very much in common with winching in the 60s.
The only difference is that the winches grew stronger in accordance to
the rising weight and speed of the gliders, but otherwise -at least in
Germany- very little has changed. Apart from the stronger engines the
rest of the equipment as well as the procedures are still the same as
fifty years ago.

It is not necessary (Bill - I know you are going to cry out now to
have the latest state-of-the-art gizmos (telemetry, plastic cables,
advanced speed control) to perform a perfectly safe and satisfactory
winch launch.

Cheers
Andreas

Germany- very little has changed. Apart from the stronger engines the
rest of the equipment as well as the procedures are still the same as
fifty years ago.


Here are some post 1960 hardware differences: (shooting from the
hip...

1) standardized weak links (Tost system)
2) implementation and standardization of preamble/strop/trace
3) high aspect drums/doing away with level-winds
4) synthetic cables
5) much better control of torque/speed/launch profile
6) electric winch(es)

While procedures may have remained pretty consistent in Germany
(though adapted to accommodate newer hardware setups like strops, and
some some for UHMW...) most everyone else seems to have been quite
behind on the curve and continue to play catch-up; with some groups in
doing it in distinct steps like the GFA writing a manual in 98
http://www.scribd.com/doc/24475893/Winch-Manual and BGA with their
'safe winch launch initiative started in 05 for instance:
http://www.gliding.co.uk/bgainfo/saf...hlaunching.htm , which
have changed SOP in those places as far as I can tell. Also up until
quite recently, a complete mathematical model of the entire launch did
not exist, only partial models. This information is (debatably)
relevant to further hardware and procedural evolution as well, pushing
it even closer towards science and further from it's trial and error
past.

Details aside, the point is if you look at 40-50yrs of winching as a
generic lump sum the picture looks undeservedly bleak compared to
looking at it by what is now commonly being done abroad, with Germany
leading the way with a long record of safety and good procedures.
(which I have a hard time imagining there being *some* changes in the
last 50yrs of German winching though...

-Paul

On Aug 15, 1:21*pm, Andreas Maurer wrote:
On Sun, 15 Aug 2010 10:29:49 -0700 (PDT), sisu1a

wrote:
Modern winching is pretty much a science and has come a long way since
the 60s so it does not do the soaring community (US at least...) a
favor to combine it all into single raw statistics cause it paints a
negative biased picture based on irrelevant data. *

Hmmm... I beg to differ.
Modern winching has very much in common with winching in the 60s.
The only difference is that the winches grew stronger in accordance to
the rising weight and speed of the gliders, but otherwise -at least in
Germany- very little has changed. Apart from the stronger engines the
rest of the equipment as well as the procedures are still the same as
fifty years ago.

It is not necessary (Bill - I know you are going to cry out now *to
have the latest state-of-the-art gizmos (telemetry, plastic cables,
advanced speed control) to perform a perfectly safe and satisfactory
winch launch.

Cheers
Andreas

Actually, I don't disagree. You don't need all new stuff to be safe
but then you can drive a 1960's car and be safe too - as long as
you're careful not to hit anything or get hit. It's a fact that
people driving new cars with air bags and crush zones drive a lot more
aggressively. That's basically what you get from the new winch
designs. Easier, safer launches with greater performance.

Dyneema is an exception. It has been proven safer than steel cable by
every industry that has adopted it - there's lots of industrial safety
data on that. Besides being safer, it's just way nicer to work with.

On Sun, 15 Aug 2010 19:56:16 -0700 (PDT), bildan
wrote:



That's basically what you get from the new winch
designs. Easier, safer launches with greater performance.
Nope.


Dyneema is an exception. It has been proven safer than steel cable by
every industry that has adopted it - there's lots of industrial safety
data on that. Besides being safer, it's just way nicer to work with.

Hmmm... on my airfield (we were the first ones to use Dyneema) we
already had more than only a couple of incidents that were directly
related to the use of Dyneema and wouldn't have happened with steel
cable. We came to the conclusion that -at least on my airfield- steel
cable offers more advantages than disadvatages than Dyneema.

Cheers
Andreas

On Aug 16, 8:19*am, Andreas Maurer wrote:
On Sun, 15 Aug 2010 19:56:16 -0700 (PDT), bildan
wrote:

That's basically what you get from the new winch
designs. *Easier, safer launches with greater performance.

Nope.

Dyneema is an exception. *It has been proven safer than steel cable by
every industry that has adopted it - there's lots of industrial safety
data on that. *Besides being safer, it's just way nicer to work with.

Hmmm... on my airfield (we were the first ones to use Dyneema) we
already had more than only a couple of incidents that were directly
related to the use of Dyneema and wouldn't have happened with steel
cable. We came to the conclusion that -at least on my airfield- steel
cable offers more advantages than disadvatages than Dyneema.

Cheers
Andreas

I very much doubt yours was the first airfield to use Dyneema since
that would have been in 1998 in Germany and I strongly suspect the
analysis of your incidents was seriously flawed. Dyneema is safer,
period. Airfields have no influence on that.

However, simply replacing steel with Dyneema and attempting to use the
same procedures as with steel will cause problems. Those are
transition issues, not Dyneema issues. The winch must be modified and
the operational rules must be changed to make a successful transition.

bildan wrote:
Dyneema is safer, period.

How so? Dyneema isn't elastic, so it doesn't snap back when it breaks,
but that's the only difference safetywise.

the operational rules must be changed to make a successful transition.

Which operation rules would these be? At our field, we successfully
changed from steel to Dyneema a couple of years ago without changing any
operation rules whatsoever. What did we miss? Of course Dyneema has a
slightly different feel, especially for the winch driver, but that's no
change in operation rules.

On Mon, 16 Aug 2010 17:22:19 +0200, John Smith
wrote:


Which operation rules would these be? At our field, we successfully
changed from steel to Dyneema a couple of years ago without changing any
operation rules whatsoever. What did we miss? Of course Dyneema has a
slightly different feel, especially for the winch driver, but that's no
change in operation rules.

We are having problems with cable breaks in crosswind situations -
Dyneemy tends to float for a long time and gets blown all over the
place even if the wind is weak. We had a couple of close calls until
we learned the hard way that we had to stop the complete operation
(including landings of powered aircraft) on the airfield until the
Dyneemy cable has definitely been moved out of the way (something that
usually takes ten to fifteen minutes). The light Dyneemy rope lies on
the grass and can easily be picked up by the gear of any passing
aircraft.
Combine this with an increased number of cable breaks compared to the
steel cable, and you can imagine that the Dyneemy cable costs us some
headaches...


An other problem unique to the Dyneemy cable is a nearby road (1.500
ft away) that already got blocked by a broken Dyneemy cable.

In comparison, our steel cables fall more or less vertically (even in
string winds), causing us no such problems.

We operate two winches on my airfield, one using Dyneema, one steel
cable.


Cheers
Andreas

On Aug 16, 4:02*pm, bildan wrote:
On Aug 16, 8:19*am, Andreas Maurer wrote:





On Sun, 15 Aug 2010 19:56:16 -0700 (PDT), bildan
wrote:

That's basically what you get from the new winch
designs. *Easier, safer launches with greater performance.

Nope.

Dyneema is an exception. *It has been proven safer than steel cable by
every industry that has adopted it - there's lots of industrial safety
data on that. *Besides being safer, it's just way nicer to work with..

Hmmm... on my airfield (we were the first ones to use Dyneema) we
already had more than only a couple of incidents that were directly
related to the use of Dyneema and wouldn't have happened with steel
cable. We came to the conclusion that -at least on my airfield- steel
cable offers more advantages than disadvatages than Dyneema.

Cheers
Andreas

I very much doubt yours was the first airfield to use Dyneema since
that would have been in 1998 in Germany and I strongly suspect the
analysis of your incidents was seriously flawed. *Dyneema is safer,
period. *Airfields have no influence on that.

However, simply replacing steel with Dyneema and attempting to use the
same procedures as with steel will cause problems. *Those are
transition issues, not Dyneema issues. *The winch must be modified and
the operational rules must be changed to make a successful transition.-

Why? We successfully ran a comparative trial with UHWPE cable on one
drum and steel cable on the other drum of a slight modified two drum
Tost winch (mainly to prevent drum crushing, which is a known problem
with UHMWPE synthetic cables). The winch drivers had no difficulty
coping with either type of cable.

Derek C

On Mon, 16 Aug 2010 08:02:39 -0700 (PDT), bildan
wrote:


I very much doubt yours was the first airfield to use Dyneema since
that would have been in 1998 in Germany
and I strongly suspect the
analysis of your incidents was seriously flawed. Dyneema is safer,
period. Airfields have no influence on that.

Bill, I really admire your ability to judge a situation from the other
side of the pond.
You neither know about the incidents we had, nor you have the
slightest idea about the enviroment our Dyneema is operated in.

Yet you dare tto " I strongly suspect the analysis of your incidents
was seriously flawed".

Bold, Sir. Very bold.
Unfortunately you simply have no clue.



Andreas