Winch Launch Safety Study

On Mar 18, 12:30*pm, Derek Copeland wrote:

2) Obviously you have never watched a dangerously steep, overpowered,
over-rotation on a winch launch. I have!

No, I haven't seen any of the weird things you describe. They all
seem to happen in your immediate vicinity. I wonder why.

At 23:53 18 March 2009, bildan wrote:
On Mar 18, 12:30=A0pm, Derek Copeland wrote:

2) Obviously you have never watched a dangerously steep, overpowered,
over-rotation on a winch launch. I have!

No, I haven't seen any of the weird things you describe. They all
seem to happen in your immediate vicinity. I wonder why.

Probably because I'm a gliding instructor at a large and very busy club
that does a lot of winch launching. I also visit other clubs that winch
launch.

I should add that probably 99% of winch launches go to plan (including
deliberate practice launch failures by instructors) without any
difficulties. About 1% suffer cable or weak link breaks, or other
technical failures of one sort or another. Given proper training these
should be just an inconvenience, rather than an emergency situation.

Once it was recognised that over powered winch launches were a problem for
lighter gliders, we reduced the power settings used for these types and
opened the winch engine throttles a bit more slowly. I haven't seen a
'rocket launch' for quite a few years now.

Derek Copeland

In message , Derek Copeland
writes
At 23:53 18 March 2009, bildan wrote:
On Mar 18, 12:30=A0pm, Derek Copeland wrote:

2) Obviously you have never watched a dangerously steep, overpowered,
over-rotation on a winch launch. I have!

No, I haven't seen any of the weird things you describe. They all
seem to happen in your immediate vicinity. I wonder why.

Probably because I'm a gliding instructor at a large and very busy club
that does a lot of winch launching. I also visit other clubs that winch
launch.

I should add that probably 99% of winch launches go to plan (including
deliberate practice launch failures by instructors) without any
difficulties. About 1% suffer cable or weak link breaks, or other
technical failures of one sort or another. Given proper training these
should be just an inconvenience, rather than an emergency situation.

I have over 300 winch launches - not many by some people's standards but
still a fair number. I have had only 1 genuine launch failure (caused
by the club member driving the winch, not by me or by equipment
failure), so either I'm due a run of cable breaks and the like, or the
percentage of failures is better for some pilots/ glider types than
others... (or a bit of both of course)

snip

--
Surfer!
Email to: ramwater at uk2 dot net

bildan wrote:

On Mar 18, 12:30 pm, Derek Copeland wrote:

2) Obviously you have never watched a dangerously steep, overpowered,
over-rotation on a winch launch. I have!

No, I haven't seen any of the weird things you describe. They all
seem to happen in your immediate vicinity. I wonder why.
Hi Bill

Derek is not alone here.

As additional example - Std Cirrus can also be coaxed into too steep a
climb with too much power too fast.

In this case it is often a combination of
- poor seatbelt location, which allows the pilot to slide back on launch.
- full flying elevator - which is possible to stall if one holds the
stick full forward. (Low speed + big angular deflection)
- aft CG with a light pilot

Maybe if you only ever see launches of modern glass, or heavy two
seaters, with experienced winch drivers who know the different types,
you will not see this. I have yet to meet the perfect winch driver. At a
busy club, or where the winch driver is inexperienced with the glider
type or just inexperienced it is easy on a powerful winch to apply too
much initial power. And a little too fast on the throttle at the start
is very dangerous for a range of gliders.

Basically excessive acceleration can use most or all of the available
control authority. One more thing, like a gust / thermal / cable break
and you exceed the authority and have an accident. Best to avoid. Best
way to avoid is to train winch driving technique correctly. Denial gets
people hurt.

Power limited winches are no fun either...

Bruce