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Old March 19th 09, 03:03 PM posted to rec.aviation.soaring
Bruce
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Default Winch Launch Safety Study

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