On Saturday, December 10, 2016 at 3:15:06 AM UTC-7, Don Johnstone wrote:
At 04:19 10 December 2016,
wrote:
On Friday, December 9, 2016 at 8:45:05 AM UTC-7, Don
Johnstone wrote:
At 08:24 09 December 2016, Pete Smith wrote:
No, the position changes subtly.

On my cirrus and N2 it is at the lower left of the stick box
quadrant,=
=20
o
the=20
N3 in question and later gliders it is in the upper left.

Please read the accident report and its conclusions.

The accident described in the report was not so much of an
issue=20
when Earlier ASW,17, 18,19,20 were designed and built. Same
applied=20
to SH.
The accident is directly related to more powerful winches. The
same=20
situation would develop with less powerful winches but it took
much=20
much longer. There was more of a ground run to recognise the
wing=20
on the ground and the acceleration was much less which meant
that=20
when it went wrong it went wrong much slower with more time
to=20
react. Not so with a modern powerful winch, when the problem
occurs=20
it goes wrong very quickly, probably too quickly for any chance
for a=20
meaningful reaction. What is described has always happened
from time=20
to time, the only difference is that it did not start killing people
unti=
l
=20
the winches got powerful.

Muddled thinking, Don.

Not muddled, incomplete. The problem is far too complex to
describe in a short post.

All winches have throttles so they produce no more power than
the winch
ope=
rator chooses. If the winch seems too powerful, you're problem is
with
the=
winch operator, not the winch.

In part, yes however the difference is in what is possible. A less
powerful winch is incapable of the rapid acceleration. People make
mistakes, with a less powerful winch the operator cannot make the
mistake of applying too much power. A powerful winch has very
little to do with the cause, it has everything to do with the outcome.

Did "powerful" winches cause a wing drop and subsequent
ground loop?
Highl=
y unlikely. The problem is far more likely to be with pilot training
and
g=
eneral winch operations.

No, see above, the more powerful winch effects the outcome.

Wings go down on winch launch for three main reasons. =20

One, excessively slow acceleration allows a wing drop before the
pilot
gain=
s aileron control - same as with aero tow. The difference is with a
CG
hoo=
k an ensuing ground loop is going to be more violent. It's much
safer to
g=
et the glider up to aileron control airspeed in the minimum time.

Two, with a fast accelerating winch, should the pilot begin the
ground
roll=
with aileron input, they will take effect suddenly forcing a wing
tip to
t=
he ground before the pilot can react - consciously centering the
stick
befo=
re the launch starts is critical. Avoiding over-controlling ailerons
is
eq=
ually important.

Three, wing "runners" sometimes mishandle the situation. If they
are
accus=
tomed to aero tow, they will be surprised how quickly the tip must
be
relea=
sed.

Post hoc, ergo propter hoc. It seems widely believed that the "wing
drop" is a cause when it is far more likely it is a symptom. To take
your points individually. It used to be popular for pilots to apply
aileron and rudder, prior to moving on a winch launch to anticipate
wing drop in a crosswind, and people got away with this on slower
accelerating winches. Hopefully we have trained this out, certainly
something I am very pedantic about. All the controls, especially the
rudder should be central. The latest advice to wing runners is if
there is any significant force required for them to keep the wings
level the launch should be stopped and the pilot appraised. I would
go further and say if there is any significant force required, with
the ailerons central, then the launch should not take place at all.
Excessively slow acceleration does not cause wing drop, wing drop
is caused by aerodynamic forces. The slower acceleration does
reduce the effectiveness of the control making recovery more
difficult. The wing drop is still a symptom of a developing problem,
not a cause.

I have never said that a powerful winch is the cause of the problem,
it isn't. The same problem occurred from time to time on less
powerful winches but over a much longer period of time and less
energy was available to be put into the glider. The increased power
effects the outcome with the increase of available energy and
therefore the larger divergence and reduced time period over which
the incident takes place. If a control is inappropriately applied the
effect is much greater with the higher speed.

The problem has always been there, it is just that before powerful
winches it did not tend to kill people.




It's not complicated. As with most aviation safety issues, the solution to wing drops is speed and altitude. Speed for aileron control and altitude to get the wing tips away from the ground. Getting both quickly reduces the risk.