Winch Launch - Fatal

[Jock Proudfoot]

[Jock Proudfoot]

At 14:06 06 December 2016, Jock Proudfoot wrote:

Footage of the accident, in which the victim was dragged upside
down along the runway, was recorded on the centre's CCTV and is
now being studied by accident investigators.

http://www.heraldscotland.com/news/13071944.Glider_pilot_killed_i
n_freak_accident_during_take_off/

[Tango Whisky]

Le mardi 6 décembre 2016 16:15:05 UTC+1, Jock Proudfoot a écritÂ*:
> At 14:06 06 December 2016, Jock Proudfoot wrote:
>
> Footage of the accident, in which the victim was dragged upside
> down along the runway, was recorded on the centre's CCTV and is
> now being studied by accident investigators.
>
> http://www.heraldscotland.com/news/13071944.Glider_pilot_killed_i
> n_freak_accident_during_take_off/

That's from 2012.

[Jonathan St. Cloud]

What happened in this accident to cause the N3 to "flip over" in the early stage of launch?

On Tuesday, December 6, 2016 at 7:15:05 AM UTC-8, Jock Proudfoot wrote:
> At 14:06 06 December 2016, Jock Proudfoot wrote:
>
> Footage of the accident, in which the victim was dragged upside
> down along the runway, was recorded on the centre's CCTV and is
> now being studied by accident investigators.
>
> http://www.heraldscotland.com/news/13071944.Glider_pilot_killed_i
> n_freak_accident_during_take_off/

[Martin Gregorie[_5_]]

On Tue, 06 Dec 2016 15:04:50 +0000, Jock Proudfoot wrote:

> http://www.heraldscotland.com/news/13071944.Glider_pilot_killed_i
> n_freak_accident_during_take_off/

This report has nothing to do with either of the recent fatal accidents.

It is about a Nimbus 3 winching accident at Portmoak in September 2012,
over four years ago.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Don Johnstone[_4_]]

At 15:28 06 December 2016, Tango Whisky wrote:
>Le mardi 6 d=C3=A9cembre 2016 16:15:05 UTC+1, Jock Proudfoot
a =C3=A9crit=
>=C2=A0:
>> At 14:06 06 December 2016, Jock Proudfoot wrote:
>>=20
>> Footage of the accident, in which the victim was dragged
upside=20
>> down along the runway, was recorded on the centre's CCTV and
is=20
>> now being studied by accident investigators.
>>=20
>>
http://www.heraldscotland.com/news/13071944.Glider_pilot_killed_i
>> n_freak_accident_during_take_off/
>
>That's from 2012.

The formal accident report is here:

https://www.gov.uk/aaib-reports/schempp-hirth-nimbus-3-glider-g-
eenn-4-september-2012

[Don Johnstone[_4_]]

At 15:28 06 December 2016, Tango Whisky wrote:
>Le mardi 6 d=C3=A9cembre 2016 16:15:05 UTC+1, Jock Proudfoot
a =C3=A9crit=
>=C2=A0:
>> At 14:06 06 December 2016, Jock Proudfoot wrote:
>>=20
>> Footage of the accident, in which the victim was dragged
upside=20
>> down along the runway, was recorded on the centre's CCTV and
is=20
>> now being studied by accident investigators.
>>=20
>>
http://www.heraldscotland.com/news/13071944.Glider_pilot_killed_i
>> n_freak_accident_during_take_off/
>
>That's from 2012.

The formal accident report is here:

https://www.gov.uk/aaib-reports/schempp-hirth-nimbus-3-glider-g-
eenn-4-september-2012

[Greg O'Hagan]

At 16:27 06 December 2016, Jonathan St. Cloud wrote:
>What happened in this accident to cause the N3 to "flip over" in the
early
>stage of launch?
>
>On Tuesday, December 6, 2016 at 7:15:05 AM UTC-8, Jock Proudfoot wrote:
>> At 14:06 06 December 2016, Jock Proudfoot wrote:
>>
>> Footage of the accident, in which the victim was dragged upside
>> down along the runway, was recorded on the centre's CCTV and is
>> now being studied by accident investigators.
>>
>> http://www.heraldscotland.com/news/13071944.Glider_pilot_killed_i
>> n_freak_accident_during_take_off/
>
>
See below.
https://assets.publishing.service.gov.uk/media/5422fd21e5274a1317000923/Schempp-Hirth_Nimbus-3_glider_G-EENN_06-13.pdf

[Greg O'Hagan]

At 16:27 06 December 2016, Jonathan St. Cloud wrote:
>What happened in this accident to cause the N3 to "flip over" in the
early
>stage of launch?
>
>On Tuesday, December 6, 2016 at 7:15:05 AM UTC-8, Jock Proudfoot wrote:
>> At 14:06 06 December 2016, Jock Proudfoot wrote:
>>
>> Footage of the accident, in which the victim was dragged upside
>> down along the runway, was recorded on the centre's CCTV and is
>> now being studied by accident investigators.
>>
>> http://www.heraldscotland.com/news/13071944.Glider_pilot_killed_i
>> n_freak_accident_during_take_off/
>
>
See below.
https://assets.publishing.service.gov.uk/media/5422fd21e5274a1317000923/Schempp-Hirth_Nimbus-3_glider_G-EENN_06-13.pdf

[Dan Marotta]

I saw that happen to a Nimbus II on aero tow back in the 90s. The pilot
induced a pitch oscillation (PIO) right at lift off, the glider pitched
up to near vertical, and rotated to the right dragging the wingtip and
cartwheeling. That time the pilot survived, though the fire department
trashed the glider cutting him out of the wreck.

On 12/6/2016 9:47 AM, Greg O'Hagan wrote:
> At 16:27 06 December 2016, Jonathan St. Cloud wrote:
>> What happened in this accident to cause the N3 to "flip over" in the
> early
>> stage of launch?
>>
>> On Tuesday, December 6, 2016 at 7:15:05 AM UTC-8, Jock Proudfoot wrote:
>>> At 14:06 06 December 2016, Jock Proudfoot wrote:
>>>
>>> Footage of the accident, in which the victim was dragged upside
>>> down along the runway, was recorded on the centre's CCTV and is
>>> now being studied by accident investigators.
>>>
>>> http://www.heraldscotland.com/news/13071944.Glider_pilot_killed_i
>>> n_freak_accident_during_take_off/
>>
> See below.
> https://assets.publishing.service.gov.uk/media/5422fd21e5274a1317000923/Schempp-Hirth_Nimbus-3_glider_G-EENN_06-13.pdf
>

--
Dan, 5J

[Martin Gregorie[_5_]]

On Tue, 06 Dec 2016 08:27:58 -0800, Jonathan St. Cloud wrote:

> What happened in this accident to cause the N3 to "flip over" in the
> early stage of launch?
>
Read this:

https://assets.publishing.service.gov.uk/media/5422fd21e5274a1317000923/
Schempp-Hirth_Nimbus-3_glider_G-EENN_06-13.pdf

Its the full AAIB report on this accident and contains full and useful
discussions about wing-drops during winch launches and of the importance
of cockpit layout with regard to interference between flying controls and
the hook release knob: both are relevant in this case.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Jonathon May[_2_]]

At 17:13 06 December 2016, Dan Marotta wrote:
>I saw that happen to a Nimbus II on aero tow back in the 90s. The pilot
>induced a pitch oscillation (PIO) right at lift off, the glider pitched
>up to near vertical, and rotated to the right dragging the wingtip and
>cartwheeling. That time the pilot survived, though the fire department
>trashed the glider cutting him out of the wreck.
>
>On 12/6/2016 9:47 AM, Greg O'Hagan wrote:
>> At 16:27 06 December 2016, Jonathan St. Cloud wrote:
>>> What happened in this accident to cause the N3 to "flip over" in the
>> early
>>> stage of launch?
>>>
>>> On Tuesday, December 6, 2016 at 7:15:05 AM UTC-8, Jock Proudfoot
wrote:
>>>> At 14:06 06 December 2016, Jock Proudfoot wrote:
>>>>
>>>> Footage of the accident, in which the victim was dragged upside
>>>> down along the runway, was recorded on the centre's CCTV and is
>>>> now being studied by accident investigators.
>>>>
>>>> http://www.heraldscotland.com/news/13071944.Glider_pilot_killed_i
>>>> n_freak_accident_during_take_off/
>>>
>> See below.
>>
>https://assets.publishing.service.gov.uk/media/5422fd21e5274a131700092
3/Schempp-Hirth_Nimbus-3_glider_G-EENN_06-13.pdf
>>
>
>--
>Dan, 5J

It can be hard to release in a schemmp if the stick is hard over to the
left.
So tie a short loop of parachute cord or similar round the release and keep
it
in your left hand .
>

[Don Johnstone[_4_]]

At 19:13 06 December 2016, Jonathon May wrote:
>At 17:13 06 December 2016, Dan Marotta wrote:
>>I saw that happen to a Nimbus II on aero tow back in the 90s.
The pilot
>>induced a pitch oscillation (PIO) right at lift off, the glider
pitched
>>up to near vertical, and rotated to the right dragging the wingtip
and
>>cartwheeling. That time the pilot survived, though the fire
department
>>trashed the glider cutting him out of the wreck.
>>
>>On 12/6/2016 9:47 AM, Greg O'Hagan wrote:
>>> At 16:27 06 December 2016, Jonathan St. Cloud wrote:
>>>> What happened in this accident to cause the N3 to "flip
over" in the
>>> early
>>>> stage of launch?
>>>>
>>>> On Tuesday, December 6, 2016 at 7:15:05 AM UTC-8, Jock
Proudfoot
>wrote:
>>>>> At 14:06 06 December 2016, Jock Proudfoot wrote:
>>>>>
>>>>> Footage of the accident, in which the victim was dragged
upside
>>>>> down along the runway, was recorded on the centre's
CCTV and is
>>>>> now being studied by accident investigators.
>>>>>
>>>>>
http://www.heraldscotland.com/news/13071944.Glider_pilot_killed
_i
>>>>> n_freak_accident_during_take_off/
>>>>
>>> See below.
>>>
>>https://assets.publishing.service.gov.uk/media/5422fd21e5274a
131700092
>3/Schempp-Hirth_Nimbus-3_glider_G-EENN_06-13.pdf
>>>
>>
>>--
>>Dan, 5J
>
>It can be hard to release in a schemmp if the stick is hard over to
th
>left.
>So tie a short loop of parachute cord or similar round the release
and kee
>it
>in your left hand .
>
I am 6 feet tall and if I have the straps done up tight I find it
difficult to reach the release so I do what Jonathan has suggested
and have a loop of paracord secured to the release knob and round
my wrist. Having experienced difficulty in releasing the cable under
tension, using the knob or the cord I am not completely sure that
would work and I am not keen to find out.
I used the same system in my ASW17 for a different reason.

[Jonathon May[_2_]]

At 20:44 06 December 2016, Don Johnstone wrote:
>At 19:13 06 December 2016, Jonathon May wrote:
>>At 17:13 06 December 2016, Dan Marotta wrote:
>>>I saw that happen to a Nimbus II on aero tow back in the 90s.
>The pilot
>>>induced a pitch oscillation (PIO) right at lift off, the glider
>pitched
>>>up to near vertical, and rotated to the right dragging the wingtip
>and
>>>cartwheeling. That time the pilot survived, though the fire
>department
>>>trashed the glider cutting him out of the wreck.
>>>
>>>On 12/6/2016 9:47 AM, Greg O'Hagan wrote:
>>>> At 16:27 06 December 2016, Jonathan St. Cloud wrote:
>>>>> What happened in this accident to cause the N3 to "flip
>over" in the
>>>> early
>>>>> stage of launch?
>>>>>
>>>>> On Tuesday, December 6, 2016 at 7:15:05 AM UTC-8, Jock
>Proudfoot
>>wrote:
>>>>>> At 14:06 06 December 2016, Jock Proudfoot wrote:
>>>>>>
>>>>>> Footage of the accident, in which the victim was dragged
>upside
>>>>>> down along the runway, was recorded on the centre's
>CCTV and is
>>>>>> now being studied by accident investigators.
>>>>>>
>>>>>>
>http://www.heraldscotland.com/news/13071944.Glider_pilot_killed
>_i
>>>>>> n_freak_accident_during_take_off/
>>>>>
>>>> See below.
>>>>
>>>https://assets.publishing.service.gov.uk/media/5422fd21e5274a
>131700092
>>3/Schempp-Hirth_Nimbus-3_glider_G-EENN_06-13.pdf
>>>>
>>>
>>>--
>>>Dan, 5J
>>
>>It can be hard to release in a schemmp if the stick is hard over to
>th
>>left.
>>So tie a short loop of parachute cord or similar round the release
>and kee
>>it
>>in your left hand .
>>
>I am 6 feet tall and if I have the straps done up tight I find it
>difficult to reach the release so I do what Jonathan has suggested
>and have a loop of paracord secured to the release knob and round
>my wrist. Having experienced difficulty in releasing the cable under
>tension, using the knob or the cord I am not completely sure that
>would work and I am not keen to find out.
>I used the same system in my ASW17 for a different reason.

Update on schemmp
The brochure for the new V3 is out and the release as moved to the panel.
>
>

[Jonathan St. Cloud]

Schleicher has located their release high on lefthand side of cockpit wall for decades, right where it should be.

On Wednesday, December 7, 2016 at 12:45:07 PM UTC-8, Jonathon May wrote:
> At 20:44 06 December 2016, Don Johnstone wrote:
> >At 19:13 06 December 2016, Jonathon May wrote:
> >>At 17:13 06 December 2016, Dan Marotta wrote:
> >>>I saw that happen to a Nimbus II on aero tow back in the 90s.
> >The pilot
> >>>induced a pitch oscillation (PIO) right at lift off, the glider
> >pitched
> >>>up to near vertical, and rotated to the right dragging the wingtip
> >and
> >>>cartwheeling. That time the pilot survived, though the fire
> >department
> >>>trashed the glider cutting him out of the wreck.
> >>>
> >>>On 12/6/2016 9:47 AM, Greg O'Hagan wrote:
> >>>> At 16:27 06 December 2016, Jonathan St. Cloud wrote:
> >>>>> What happened in this accident to cause the N3 to "flip
> >over" in the
> >>>> early
> >>>>> stage of launch?
> >>>>>
> >>>>> On Tuesday, December 6, 2016 at 7:15:05 AM UTC-8, Jock
> >Proudfoot
> >>wrote:
> >>>>>> At 14:06 06 December 2016, Jock Proudfoot wrote:
> >>>>>>
> >>>>>> Footage of the accident, in which the victim was dragged
> >upside
> >>>>>> down along the runway, was recorded on the centre's
> >CCTV and is
> >>>>>> now being studied by accident investigators.
> >>>>>>
> >>>>>>
> >http://www.heraldscotland.com/news/13071944.Glider_pilot_killed
> >_i
> >>>>>> n_freak_accident_during_take_off/
> >>>>>
> >>>> See below.
> >>>>
> >>>https://assets.publishing.service.gov.uk/media/5422fd21e5274a
> >131700092
> >>3/Schempp-Hirth_Nimbus-3_glider_G-EENN_06-13.pdf
> >>>>
> >>>
> >>>--
> >>>Dan, 5J
> >>
> >>It can be hard to release in a schemmp if the stick is hard over to
> >th
> >>left.
> >>So tie a short loop of parachute cord or similar round the release
> >and kee
> >>it
> >>in your left hand .
> >>
> >I am 6 feet tall and if I have the straps done up tight I find it
> >difficult to reach the release so I do what Jonathan has suggested
> >and have a loop of paracord secured to the release knob and round
> >my wrist. Having experienced difficulty in releasing the cable under
> >tension, using the knob or the cord I am not completely sure that
> >would work and I am not keen to find out.
> >I used the same system in my ASW17 for a different reason.
>
> Update on schemmp
> The brochure for the new V3 is out and the release as moved to the panel.
> >
> >

[ND]

On Wednesday, December 7, 2016 at 4:44:16 PM UTC-5, Jonathan St. Cloud wrote:
> Schleicher has located their release high on lefthand side of cockpit wall for decades, right where it should be.
>
> On Wednesday, December 7, 2016 at 12:45:07 PM UTC-8, Jonathon May wrote:
> > At 20:44 06 December 2016, Don Johnstone wrote:
> > >At 19:13 06 December 2016, Jonathon May wrote:
> > >>At 17:13 06 December 2016, Dan Marotta wrote:
> > >>>I saw that happen to a Nimbus II on aero tow back in the 90s.
> > >The pilot
> > >>>induced a pitch oscillation (PIO) right at lift off, the glider
> > >pitched
> > >>>up to near vertical, and rotated to the right dragging the wingtip
> > >and
> > >>>cartwheeling. That time the pilot survived, though the fire
> > >department
> > >>>trashed the glider cutting him out of the wreck.
> > >>>
> > >>>On 12/6/2016 9:47 AM, Greg O'Hagan wrote:
> > >>>> At 16:27 06 December 2016, Jonathan St. Cloud wrote:
> > >>>>> What happened in this accident to cause the N3 to "flip
> > >over" in the
> > >>>> early
> > >>>>> stage of launch?
> > >>>>>
> > >>>>> On Tuesday, December 6, 2016 at 7:15:05 AM UTC-8, Jock
> > >Proudfoot
> > >>wrote:
> > >>>>>> At 14:06 06 December 2016, Jock Proudfoot wrote:
> > >>>>>>
> > >>>>>> Footage of the accident, in which the victim was dragged
> > >upside
> > >>>>>> down along the runway, was recorded on the centre's
> > >CCTV and is
> > >>>>>> now being studied by accident investigators.
> > >>>>>>
> > >>>>>>
> > >http://www.heraldscotland.com/news/13071944.Glider_pilot_killed
> > >_i
> > >>>>>> n_freak_accident_during_take_off/
> > >>>>>
> > >>>> See below.
> > >>>>
> > >>>https://assets.publishing.service.gov.uk/media/5422fd21e5274a
> > >131700092
> > >>3/Schempp-Hirth_Nimbus-3_glider_G-EENN_06-13.pdf
> > >>>>
> > >>>
> > >>>--
> > >>>Dan, 5J
> > >>
> > >>It can be hard to release in a schemmp if the stick is hard over to
> > >th
> > >>left.
> > >>So tie a short loop of parachute cord or similar round the release
> > >and kee
> > >>it
> > >>in your left hand .
> > >>
> > >I am 6 feet tall and if I have the straps done up tight I find it
> > >difficult to reach the release so I do what Jonathan has suggested
> > >and have a loop of paracord secured to the release knob and round
> > >my wrist. Having experienced difficulty in releasing the cable under
> > >tension, using the knob or the cord I am not completely sure that
> > >would work and I am not keen to find out.
> > >I used the same system in my ASW17 for a different reason.
> >
> > Update on schemmp
> > The brochure for the new V3 is out and the release as moved to the panel.
> > >
> > >

hmmmm in my 20, its located exactly where they normally are on a schempp glider. i realize they were built in the 80's but cmon man, whats with the SH bashing? it's one thing to prefer a certain manufacturer, but you have to acknowledge that they're all good gliders.

[Jonathan St. Cloud]

I never bashed any manufacturer, I just stated a fact. In the mid 1990's my ASW-24 had the release handle high in LHS of cockpit wall, same place modern Schleichers' have them, and it doesn't take panel space and does not interfere with full motion of stick. My V2C and N4 had the release handle in a poorly designed and thought out location. Not bashing anyone just stating facts.

On Thursday, December 8, 2016 at 5:31:32 AM UTC-8, ND wrote:
> On Wednesday, December 7, 2016 at 4:44:16 PM UTC-5, Jonathan St. Cloud wrote:
> > Schleicher has located their release high on lefthand side of cockpit wall for decades, right where it should be.

>
> hmmmm in my 20, its located exactly where they normally are on a schempp glider. i realize they were built in the 80's but cmon man, whats with the SH bashing? it's one thing to prefer a certain manufacturer, but you have to acknowledge that they're all good gliders.

[[email protected]]

On Thursday, December 8, 2016 at 1:22:32 PM UTC-5, Jonathan St. Cloud wrote:
> I never bashed any manufacturer, I just stated a fact. In the mid 1990's my ASW-24 had the release handle high in LHS of cockpit wall, same place modern Schleichers' have them, and it doesn't take panel space and does not interfere with full motion of stick. My V2C and N4 had the release handle in a poorly designed and thought out location. Not bashing anyone just stating facts.
>
> On Thursday, December 8, 2016 at 5:31:32 AM UTC-8, ND wrote:
> > On Wednesday, December 7, 2016 at 4:44:16 PM UTC-5, Jonathan St. Cloud wrote:
> > > Schleicher has located their release high on lefthand side of cockpit wall for decades, right where it should be.
>
> >
> > hmmmm in my 20, its located exactly where they normally are on a schempp glider. i realize they were built in the 80's but cmon man, whats with the SH bashing? it's one thing to prefer a certain manufacturer, but you have to acknowledge that they're all good gliders.

The '24, and later ships, got the release raised after Waibel had a ground loop where he couldn't get to the release quickly enough.
That led to the loop of parachute cord connected to the release and laid across the thigh during launch that you see in a lot of 19's and 20's.
Next ship he designed- better location.
I saved my bacon a couple times.
UH

[Scott Williams]

There are few things in this world which arise out of nothing, The release location in schempp hirth gliders just inside the pilots left knee/thigh is at least as old as the austrias and the shk s. the later cirri and ventus , etc, were continuing a design feature which had worked in the past.
The potential interference may never have been reported due to the rare and lethal nature of the adverse event.
Scott.

[Pete Smith[_5_]]

No, the position changes subtly.

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

Please read the accident report and its conclusions.

At 02:17 09 December 2016, Scott Williams wrote:
>There are few things in this world which arise out of nothing, The
release
>=
>location in schempp hirth gliders just inside the pilots left knee/thigh
>is=
> at least as old as the austrias and the shk s. the later cirri and
ventus
>=
>, etc, were continuing a design feature which had worked in the past.
>The potential interference may never have been reported due to the rare
>and=
> lethal nature of the adverse event.
>Scott.
>

[Don Johnstone[_4_]]

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

the winches got powerful.

[Jonathan St. Cloud]

So how dangerous is wench launching compared to aero-tow? I only had enough wench launches to remove the "aero-tow only" off my ticket and that was years ago.

On Friday, December 9, 2016 at 7:45:05 AM UTC-8, 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,
> o
> >the
> >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
> when Earlier ASW,17, 18,19,20 were designed and built. Same applied
> to SH.
> The accident is directly related to more powerful winches. The same
> situation would develop with less powerful winches but it took much
> much longer. There was more of a ground run to recognise the wing
> on the ground and the acceleration was much less which meant that
> when it went wrong it went wrong much slower with more time to
> react. Not so with a modern powerful winch, when the problem occurs
> it goes wrong very quickly, probably too quickly for any chance for a
> meaningful reaction. What is described has always happened from time
> to time, the only difference is that it did not start killing people until
>
> the winches got powerful.

[Duster]

Pretty dangerous for the wench, I imagine. Depending on her weight, you might need a weak link.

The Soaring Safety Foundation (US) should have the best info on this https://www.soaringsafety.org/ This is a very good resource for safety training. There have been some European and UK studies out there since they tend to winch more than US. Aero-tow kills more tow pilots than winching kills wenches.

[Don Johnstone[_4_]]

At 16:19 09 December 2016, Jonathan St. Cloud wrote:
>So how dangerous is wench launching compared to aero-tow? I only
had enough
>wench launches to remove the "aero-tow only" off my ticket and that
was
>years ago.
>
I do not have the figures but my answer would be as safe as any other
method of launching.
I do not know but I suspect the number of winch launches in the UK
runs to many thousands per year. Accidents like the one described are
very rare, the last recorded 4 years ago.
Aerotows tend to be more of a gotcha for tuggies but there are a lot
less of them so they are even less frequent.
Bungee launching tends to involve lighter gliders but has it's share of
accidents, very few fatal.
Winching is not for the unwary and less forgiving of errors than other
methods, more so since the introduction of modern powerful winches
with the ability to accelerate very very quickly.

[Duster]

......hmmmmm, I would say that those missing figures are fairly important in forming a consensus on that. We lost a passenger when a winch went bad in a two-placer a few years back. Pilot (a good one) was seriously injured. And, on the other side, a high-time pilot was killed after a PTT in Arizona http://www.kathrynsreport.com/2014/05/wickenburg-maricopa-county-arizona.html?m=1

(Another issue that needs more facts, maybe from the SSF: Are "we" putting passengers at more risk by loading them in the front seat? They are, of course, often the first ones to the scene of an accident.)

[Dan Marotta]

Wench launching can be very dangerous, especially if she's heavy and
your aim is poor...

On 12/9/2016 9:19 AM, Jonathan St. Cloud wrote:
> So how dangerous is wench launching compared to aero-tow? I only had enough wench launches to remove the "aero-tow only" off my ticket and that was years ago.
>
> On Friday, December 9, 2016 at 7:45:05 AM UTC-8, 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,
>> o
>>> the
>>> 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
>> when Earlier ASW,17, 18,19,20 were designed and built. Same applied
>> to SH.
>> The accident is directly related to more powerful winches. The same
>> situation would develop with less powerful winches but it took much
>> much longer. There was more of a ground run to recognise the wing
>> on the ground and the acceleration was much less which meant that
>> when it went wrong it went wrong much slower with more time to
>> react. Not so with a modern powerful winch, when the problem occurs
>> it goes wrong very quickly, probably too quickly for any chance for a
>> meaningful reaction. What is described has always happened from time
>> to time, the only difference is that it did not start killing people until
>>
>> the winches got powerful.

--
Dan, 5J

[Jonathan St. Cloud]

Damn autocorrect meant wrench launching.
On Friday, December 9, 2016 at 12:02:52 PM UTC-8, Dan Marotta wrote:
> Wench launching can be very dangerous, especially if she's heavy and
> your aim is poor...
>
> On 12/9/2016 9:19 AM, Jonathan St. Cloud wrote:
> > So how dangerous is wench launching compared to aero-tow? I only had enough wench launches to remove the "aero-tow only" off my ticket and that was years ago.
> >
> > On Friday, December 9, 2016 at 7:45:05 AM UTC-8, 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,
> >> o
> >>> the
> >>> 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
> >> when Earlier ASW,17, 18,19,20 were designed and built. Same applied
> >> to SH.
> >> The accident is directly related to more powerful winches. The same
> >> situation would develop with less powerful winches but it took much
> >> much longer. There was more of a ground run to recognise the wing
> >> on the ground and the acceleration was much less which meant that
> >> when it went wrong it went wrong much slower with more time to
> >> react. Not so with a modern powerful winch, when the problem occurs
> >> it goes wrong very quickly, probably too quickly for any chance for a
> >> meaningful reaction. What is described has always happened from time
> >> to time, the only difference is that it did not start killing people until
> >>
> >> the winches got powerful.
>
> --
> Dan, 5J

[Steve Leonard[_2_]]

On Friday, December 9, 2016 at 2:29:56 PM UTC-6, Jonathan St. Cloud wrote:

> Damn autocorrect meant wrench launching.

Now autocorrect has you throwing tools about!

Steve

[firsys]

On Tuesday, December 6, 2016 at 9:15:05 AM UTC-5, Jock Proudfoot wrote:
>

My early flying was nearly all launched by winch; the winches
in the 60s were pretty anaemic.
Nevertheless, the standard practice was to take up cable slack
till it was pretty straight, so the initial acceleration was
directed along the glider axis. this would remove the roll couple as described in the report.
More recently, experience at Bristol GC and the Mynd was like
a superbungee launch and I admit to some concern about the elevator
power to cope with the pitchup.

It would seem that initial acceleration should be moderated.

The PTT problem is unknown to me, but I presume it must mean
passenger temper tantrum.

JMF

[Papa3[_2_]]

I just launched a wrench the other day trying to get the *&#$@ retaining bolt out of the rudder of a Grob Twin Astir. Actually pretty cathartic.

Not to make light of this tragic situation, but a little humor hopefully won't hurt...

P3

[Dan Marotta]

Sew, ewe did not really mean two say "wench", then?

On 12/9/2016 1:29 PM, Jonathan St. Cloud wrote:
> Damn autocorrect meant wrench launching.
> On Friday, December 9, 2016 at 12:02:52 PM UTC-8, Dan Marotta wrote:
>> Wench launching can be very dangerous, especially if she's heavy and
>> your aim is poor...
>>
>> On 12/9/2016 9:19 AM, Jonathan St. Cloud wrote:
>>> So how dangerous is wench launching compared to aero-tow? I only had enough wench launches to remove the "aero-tow only" off my ticket and that was years ago.
>>>
>>> On Friday, December 9, 2016 at 7:45:05 AM UTC-8, 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,
>>>> o
>>>>> the
>>>>> 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
>>>> when Earlier ASW,17, 18,19,20 were designed and built. Same applied
>>>> to SH.
>>>> The accident is directly related to more powerful winches. The same
>>>> situation would develop with less powerful winches but it took much
>>>> much longer. There was more of a ground run to recognise the wing
>>>> on the ground and the acceleration was much less which meant that
>>>> when it went wrong it went wrong much slower with more time to
>>>> react. Not so with a modern powerful winch, when the problem occurs
>>>> it goes wrong very quickly, probably too quickly for any chance for a
>>>> meaningful reaction. What is described has always happened from time
>>>> to time, the only difference is that it did not start killing people until
>>>>
>>>> the winches got powerful.
>> --
>> Dan, 5J

--
Dan, 5J

[Jonathan St. Cloud]

The wench launch comment was meant for another newsgroup!

How dangerous is winch launching went compared to aero-tow? In the States most launches are aero-tow.

Those that know me, also know you would never see me launch a wrench, as experience has taught me never pick up a tool.

On Friday, December 9, 2016 at 2:23:31 PM UTC-8, Dan Marotta wrote:
> Sew, ewe did not really mean two say "wench", then?
>
> On 12/9/2016 1:29 PM, Jonathan St. Cloud wrote:
> > Damn autocorrect meant wrench launching.
> > On Friday, December 9, 2016 at 12:02:52 PM UTC-8, Dan Marotta wrote:
> >> Wench launching can be very dangerous, especially if she's heavy and
> >> your aim is poor...
> >>
> >> On 12/9/2016 9:19 AM, Jonathan St. Cloud wrote:
> >>> So how dangerous is wench launching compared to aero-tow? I only had enough wench launches to remove the "aero-tow only" off my ticket and that was years ago.
> >>>
> >>> On Friday, December 9, 2016 at 7:45:05 AM UTC-8, 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,
> >>>> o
> >>>>> the
> >>>>> 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
> >>>> when Earlier ASW,17, 18,19,20 were designed and built. Same applied
> >>>> to SH.
> >>>> The accident is directly related to more powerful winches. The same
> >>>> situation would develop with less powerful winches but it took much
> >>>> much longer. There was more of a ground run to recognise the wing
> >>>> on the ground and the acceleration was much less which meant that
> >>>> when it went wrong it went wrong much slower with more time to
> >>>> react. Not so with a modern powerful winch, when the problem occurs
> >>>> it goes wrong very quickly, probably too quickly for any chance for a
> >>>> meaningful reaction. What is described has always happened from time
> >>>> to time, the only difference is that it did not start killing people until
> >>>>
> >>>> the winches got powerful.
> >> --
> >> Dan, 5J
>
> --
> Dan, 5J

[Scott Williams]

I must agree with Don Johnstone,
todays winches are very powerful.
Does this result in higher launches or just much more rapid ones?

[[email protected]]

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

Muddled thinking, Don.

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

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

Wings go down on winch launch for three main reasons.

One, excessively slow acceleration allows a wing drop before the pilot gains aileron control - same as with aero tow. The difference is with a CG hook an ensuing ground loop is going to be more violent. It's much safer to get 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 the ground before the pilot can react - consciously centering the stick before the launch starts is critical. Avoiding over-controlling ailerons is equally important.

Three, wing "runners" sometimes mishandle the situation. If they are accustomed to aero tow, they will be surprised how quickly the tip must be released.

[Don Johnstone[_4_]]

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.

>
>

[Martin Gregorie[_5_]]

On Fri, 09 Dec 2016 20:19:18 -0800, Bill.Daniels wrote:

> Three, wing "runners" sometimes mishandle the situation. If they are
> accustomed to aero tow, they will be surprised how quickly the tip must
> be released.
>
Two additional points (which you may already do):

-train the wing runner to hold the tip from behind (NEVER with
fingers round the leading edge).

This makes it much less likely that the
wing runner can deflect the glider before letting go.

-teach wing runners to BALANCE the glider on its wheel, raising or
lowering the tip a bit to counter the forces generated by a cross-wind.
Done right, you need little more than a finger and thumb on either side
of the TE to keep the wing balanced despite gusts.

If the wing runner is forcing the wing level against a cross wind, then
a wing-drop is almost guaranteed when the tip is released.



--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Martin Gregorie[_5_]]

On Fri, 09 Dec 2016 18:21:35 -0800, Scott Williams wrote:

> I must agree with Don Johnstone,
> todays winches are very powerful.
>
IME the control systems in the winch are the most important factor
provided that the winch has enough power to avoid running it flat out for
most of the launch.


> Does this result in higher launches or just much more rapid ones?
>
I learned on a Supacat (240hp diesel V-8), straight drive, driver's
judgement and hand on the throttle were all that controlled the winch.
Now we have a Skylaunch (380hp LPG converted V-8), automatic gearbox,
analog launch controller which the driver can override. The Supacat used
steel cable while the Skylaunch has always used HD poly rope. I've
regularly flown my Libelle and club gliders (K21, Puchacz, Junior) off
both winches. Initial acceleration rates are similar and so are release
heights, but by and large the Skylaunch gives more consistent launches.

Oddly enough, Supacat launches were faster, typically just below Vwinch,
while the Skylaunch launches are about 5 kts slower, which feels a lot
nicer.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[[email protected]]

On Saturday, December 10, 2016 at 5:27:54 AM UTC-7, Martin Gregorie wrote:
> On Fri, 09 Dec 2016 20:19:18 -0800, Bill.Daniels wrote:
>
> > Three, wing "runners" sometimes mishandle the situation. If they are
> > accustomed to aero tow, they will be surprised how quickly the tip must
> > be released.
> >
> Two additional points (which you may already do):
>
> -train the wing runner to hold the tip from behind (NEVER with
> fingers round the leading edge).
>
> This makes it much less likely that the
> wing runner can deflect the glider before letting go.
>
> -teach wing runners to BALANCE the glider on its wheel, raising or
> lowering the tip a bit to counter the forces generated by a cross-wind.
> Done right, you need little more than a finger and thumb on either side
> of the TE to keep the wing balanced despite gusts.
>
> If the wing runner is forcing the wing level against a cross wind, then
> a wing-drop is almost guaranteed when the tip is released.
>
>
>
> --
> martin@ | Martin Gregorie
> gregorie. | Essex, UK
> org |

Yes, balancing the wing and never just "leveling" it is always a better method - for both winch and aero tow.

[[email protected]]

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.

[Peter Whitehead]

On Tuesday, 6 December 2016 14:15:05 UTC, Jock Proudfoot wrote:
>

Modern winches are powerful so the ground run is shorter, and it is this which allows greater height on launch (you are effectively lengthening the airfield compared to those with "anaemic winches"). The problem is the acceleration and reduction in time to sort out the problem with wing drop on the ground, and also a stall and wing drop (to inverted ) in the rotation (to climb).This can all happen too quickly for human responses. It kills "smart" people.

Please do read and digest (and disseminate) the following link from experts in the field, the BGA. This programme of "safe winching" has shown reduction (evidence based) in accidents and fatalities in this mode of launching.

https://www.bfgc.co.uk/Documents/Winching.pdf

Pete Whitehead

[[email protected]]

On Sunday, December 11, 2016 at 3:15:02 AM UTC-7, Peter Whitehead wrote:
> On Tuesday, 6 December 2016 14:15:05 UTC, Jock Proudfoot wrote:
> >
>
> Modern winches are powerful so the ground run is shorter, and it is this which allows greater height on launch (you are effectively lengthening the airfield compared to those with "anaemic winches"). The problem is the acceleration and reduction in time to sort out the problem with wing drop on the ground, and also a stall and wing drop (to inverted ) in the rotation (to climb).This can all happen too quickly for human responses. It kills "smart" people.
>
> Please do read and digest (and disseminate) the following link from experts in the field, the BGA. This programme of "safe winching" has shown reduction (evidence based) in accidents and fatalities in this mode of launching..
>
> https://www.bfgc.co.uk/Documents/Winching.pdf
>
> Pete Whitehead

I read every new issue of the BGA safe winching and note a slow movement toward scientific rationality such as the deletion of the ridiculous graphic showing a glider pitching up due to acceleration.

There is NO time to "sort out problems" in the ground roll - the only option is to prevent them in the first place.

1. Balance the wing, not just level it.
2. Point the glider EXACTLY at the winch.
3. PRECISELY center all controls and don't wag the stick around in the roll..
4. Above all, don't force a pilot to wobble along during an extended ground roll while struggling to keep the wings level.

A normal winch acceleration is 19 knots per second (1G) which gets the glider to aileron control airspeed in less than a second and airborne in about two seconds. If rules 1 - 3 above are followed it's almost impossible to imagine a wing drop before the glider is airborne and out of danger.

[[email protected]]

> 1. Balance the wing, not just level it.
> 2. Point the glider EXACTLY at the winch.
> 3. PRECISELY center all controls and don't wag the stick around in the roll.
> 4. Above all, don't force a pilot to wobble along during an extended ground roll while struggling to keep the wings level.
>
I have an issue with points 2 and 3: you're of course right if the winch hook is on the center line of the glider. However, many gliders (e.g. Ka-6, ASK-13, ASK-21) have an off-centre winch hook. With a left of centre hook, the initial acceleration causes a marked yaw to the right. It is much better in this case to align the glider pointing slightly to the left of the winch, and giving left rudder at the start.

[Martin Gregorie[_5_]]

On Sun, 11 Dec 2016 16:03:09 -0800, stephanevdv wrote:

>> 1. Balance the wing, not just level it.
>> 2. Point the glider EXACTLY at the winch.
>> 3. PRECISELY center all controls and don't wag the stick around in the
>> roll.
>> 4. Above all, don't force a pilot to wobble along during an extended
>> ground roll while struggling to keep the wings level.
>>
> I have an issue with points 2 and 3: you're of course right if the winch
> hook is on the center line of the glider. However, many gliders (e.g.
> Ka-6, ASK-13, ASK-21) have an off-centre winch hook. With a left of
> centre hook, the initial acceleration causes a marked yaw to the right.
> It is much better in this case to align the glider pointing slightly to
> the left of the winch, and giving left rudder at the start.

There was a discussion about this during my club's launch marshal meeting
today. The consensus was that there is a potential problem with point 3
because many pilots think 'balanced turn' and also add some aileron, thus
inviting wing drop, when leaving the ailerons centralised and just
applying rudder is the correct course. Centralising all controls avoids
this. I should add that we use SZD Juniors, which have a larger left hook
offset than any of the gliders you mention and consequently a stronger
tendency to swing right, especially if there is a cross-wind from the
right!

I start winch launches with controls centred regardless of whether I'm
flying my Libelle or one of the club's fleet (Junior, ASK-21, Puchacz or
Grob G103). In all cases you can get rudder on fast enough to control a
swing if you're paying attention, and what are you doing as PIC if you
aren't paying attention?


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Don Johnstone[_4_]]

At 00:44 12 December 2016, Martin Gregorie wrote:
>On Sun, 11 Dec 2016 16:03:09 -0800, stephanevdv wrote:
>
>>> 1. Balance the wing, not just level it.
>>> 2. Point the glider EXACTLY at the winch.
>>> 3. PRECISELY center all controls and don't wag the stick
around in the
>>> roll.
>>> 4. Above all, don't force a pilot to wobble along during an
extended
>>> ground roll while struggling to keep the wings level.
>>>
>> I have an issue with points 2 and 3: you're of course right if the
winch
>> hook is on the center line of the glider. However, many gliders
(e.g.
>> Ka-6, ASK-13, ASK-21) have an off-centre winch hook. With a
left of
>> centre hook, the initial acceleration causes a marked yaw to the
right.
>> It is much better in this case to align the glider pointing slightly
to
>> the left of the winch, and giving left rudder at the start.
>
>There was a discussion about this during my club's launch
marshal meeting
>today. The consensus was that there is a potential problem with
point 3
>because many pilots think 'balanced turn' and also add some
aileron, thus
>inviting wing drop, when leaving the ailerons centralised and just
>applying rudder is the correct course. Centralising all controls
avoids
>this. I should add that we use SZD Juniors, which have a larger
left hook
>offset than any of the gliders you mention and consequently a
stronger
>tendency to swing right, especially if there is a cross-wind from
the
>right!
>
>I start winch launches with controls centred regardless of whether
I'm
>flying my Libelle or one of the club's fleet (Junior, ASK-21,
Puchacz or
>Grob G103). In all cases you can get rudder on fast enough to
control a
>swing if you're paying attention, and what are you doing as PIC if
you
>aren't paying attention?
>
>
>--
>martin@ | Martin Gregorie
>gregorie. | Essex, UK
>org |

You are absolutely right Martin and the point you make is crucial.
Whatever the glider, the crosswind or any other factor the controls
should all be centered, or in the case of the elevator, neutral to the
trim setting or takeoff position (I find a T21 needs the stick well
forward). The controls should only ever be used to correct a
departure from the attitude required, or to select an attitude
required, never, in the context of a winch launch, to anticipate a
perceived or potential problem.
If any force is needed by the wing tip runner to hold the wings level
with the ailerons central this can be corrected by lifting or lowering
the wing by a small amount to balance, a Bill has said. If however
balance cannot be achieved with a small lowering or lifting then
serious thought should be given as to if the launch should be
attempted.

[[email protected]]

On Sunday, December 11, 2016 at 5:03:12 PM UTC-7, wrote:
> > 1. Balance the wing, not just level it.
> > 2. Point the glider EXACTLY at the winch.
> > 3. PRECISELY center all controls and don't wag the stick around in the roll.
> > 4. Above all, don't force a pilot to wobble along during an extended ground roll while struggling to keep the wings level.
> >
> I have an issue with points 2 and 3: you're of course right if the winch hook is on the center line of the glider. However, many gliders (e.g. Ka-6, ASK-13, ASK-21) have an off-centre winch hook. With a left of centre hook, the initial acceleration causes a marked yaw to the right. It is much better in this case to align the glider pointing slightly to the left of the winch, and giving left rudder at the start.

Swing due to an offset hook is minimal if the acceleration is high. Acceleration increases the download on the tail wheel forcing the glider to roll straight. In any event a slight drift to the side is of no consequence - you're not trying to fly formation on a winch.

[AS]

On Tuesday, December 13, 2016 at 4:19:31 PM UTC+1, wrote:
> On Sunday, December 11, 2016 at 5:03:12 PM UTC-7, wrote:
> > > 1. Balance the wing, not just level it.
> > > 2. Point the glider EXACTLY at the winch.
> > > 3. PRECISELY center all controls and don't wag the stick around in the roll.
> > > 4. Above all, don't force a pilot to wobble along during an extended ground roll while struggling to keep the wings level.
> > >
> > I have an issue with points 2 and 3: you're of course right if the winch hook is on the center line of the glider. However, many gliders (e.g. Ka-6, ASK-13, ASK-21) have an off-centre winch hook. With a left of centre hook, the initial acceleration causes a marked yaw to the right. It is much better in this case to align the glider pointing slightly to the left of the winch, and giving left rudder at the start.
>
> Swing due to an offset hook is minimal if the acceleration is high. Acceleration increases the download on the tail wheel forcing the glider to roll straight. In any event a slight drift to the side is of no consequence - you're not trying to fly formation on a winch.

I can confirm that to be correct! I have flown everything from the K6,8,13 and the ASW-15 with an off-set CG hook and there was never any condition that could not be corrected or controlled with rudder input.
And before someone chimes in about the oh so dangerous L-13 Y-bridle CG hooks: no - launching on just one hook because the other one fell out does not cause a spectacular ground-loop, accident or male pattern hair-loss! ;-)

Uli

[[email protected]]

On Tuesday, December 13, 2016 at 1:32:58 PM UTC-6, AS wrote:
> On Tuesday, December 13, 2016 at 4:19:31 PM UTC+1, wrote:
> > On Sunday, December 11, 2016 at 5:03:12 PM UTC-7, wrote:
> > > > 1. Balance the wing, not just level it.
> > > > 2. Point the glider EXACTLY at the winch.
> > > > 3. PRECISELY center all controls and don't wag the stick around in the roll.
> > > > 4. Above all, don't force a pilot to wobble along during an extended ground roll while struggling to keep the wings level.
> > > >
> > > I have an issue with points 2 and 3: you're of course right if the winch hook is on the center line of the glider. However, many gliders (e.g. Ka-6, ASK-13, ASK-21) have an off-centre winch hook. With a left of centre hook, the initial acceleration causes a marked yaw to the right. It is much better in this case to align the glider pointing slightly to the left of the winch, and giving left rudder at the start.
> >
> > Swing due to an offset hook is minimal if the acceleration is high. Acceleration increases the download on the tail wheel forcing the glider to roll straight. In any event a slight drift to the side is of no consequence - you're not trying to fly formation on a winch.
>
> I can confirm that to be correct! I have flown everything from the K6,8,13 and the ASW-15 with an off-set CG hook and there was never any condition that could not be corrected or controlled with rudder input.
> And before someone chimes in about the oh so dangerous L-13 Y-bridle CG hooks: no - launching on just one hook because the other one fell out does not cause a spectacular ground-loop, accident or male pattern hair-loss! ;-)
>
> Uli

Uli and Bill D beat me to it: that's exactly my experience. The offset hook myth is just that, an old wifes tale, to be used for bedtime stories to scare your children.
Herb

[[email protected]]

On Tuesday, December 13, 2016 at 3:37:14 PM UTC-7, wrote:
> On Tuesday, December 13, 2016 at 1:32:58 PM UTC-6, AS wrote:
> > On Tuesday, December 13, 2016 at 4:19:31 PM UTC+1, wrote:
> > > On Sunday, December 11, 2016 at 5:03:12 PM UTC-7, wrote:
> > > > > 1. Balance the wing, not just level it.
> > > > > 2. Point the glider EXACTLY at the winch.
> > > > > 3. PRECISELY center all controls and don't wag the stick around in the roll.
> > > > > 4. Above all, don't force a pilot to wobble along during an extended ground roll while struggling to keep the wings level.
> > > > >
> > > > I have an issue with points 2 and 3: you're of course right if the winch hook is on the center line of the glider. However, many gliders (e.g. Ka-6, ASK-13, ASK-21) have an off-centre winch hook. With a left of centre hook, the initial acceleration causes a marked yaw to the right. It is much better in this case to align the glider pointing slightly to the left of the winch, and giving left rudder at the start.
> > >
> > > Swing due to an offset hook is minimal if the acceleration is high. Acceleration increases the download on the tail wheel forcing the glider to roll straight. In any event a slight drift to the side is of no consequence - you're not trying to fly formation on a winch.
> >
> > I can confirm that to be correct! I have flown everything from the K6,8,13 and the ASW-15 with an off-set CG hook and there was never any condition that could not be corrected or controlled with rudder input.
> > And before someone chimes in about the oh so dangerous L-13 Y-bridle CG hooks: no - launching on just one hook because the other one fell out does not cause a spectacular ground-loop, accident or male pattern hair-loss! ;-)
> >
> > Uli
>
> Uli and Bill D beat me to it: that's exactly my experience. The offset hook myth is just that, an old wifes tale, to be used for bedtime stories to scare your children.
> Herb

Actually, just to be obstinate, there is a scenario where an offset hook will induce a swing to the side. That's under ridiculously low acceleration where the glider swings a bit each time the tailwheel bounces. Increase the acceleration to a normal 1G and the down-force on the tailwheel will keep the glider rolling straight.

[Don Johnstone[_4_]]

At 23:16 13 December 2016,
wrote:

>> > > > I have an issue with points 2 and 3: you're of course
right if the
>=
>winch hook is on the center line of the glider. However, many
gliders
>(e.g.=
> Ka-6, ASK-13, ASK-21) have an off-centre winch hook. With a left
of
>centre=
> hook, the initial acceleration causes a marked yaw to the right. It
is
>muc=
>h better in this case to align the glider pointing slightly to the left
of
>=
>the winch, and giving left rudder at the start.
>> > >=20
>> > > Swing due to an offset hook is minimal if the acceleration is
high.
>=
>Acceleration increases the download on the tail wheel forcing the
glider
>to=
> roll straight. In any event a slight drift to the side is of no
>consequen=
>ce - you're not trying to fly formation on a winch.
>> >=20
>> > I can confirm that to be correct! I have flown everything from
the
>K6,8=
>,13 and the ASW-15 with an off-set CG hook and there was never
any
>conditio=
>n that could not be corrected or controlled with rudder input.
>> > And before someone chimes in about the oh so dangerous L-
13 Y-bridle
>CG=
> hooks: no - launching on just one hook because the other one fell
out
>does=
> not cause a spectacular ground-loop, accident or male pattern
hair-loss!
>;=
>-)
>> >=20
>> > Uli
>>=20
>> Uli and Bill D beat me to it: that's exactly my experience. The
offset
>ho=
>ok myth is just that, an old wifes tale, to be used for bedtime
stories to
>=
>scare your children.
>> Herb
>
>Actually, just to be obstinate, there is a scenario where an offset
hook
>wi=
>ll induce a swing to the side. That's under ridiculously low
acceleration
>=
>where the glider swings a bit each time the tailwheel bounces.
Increase
>th=
>e acceleration to a normal 1G and the down-force on the tailwheel
will
>keep=
> the glider rolling straight.

In the days of yore, when gliders had compromise hooks and
winches had less power, but were still capable of getting a glider in
the air in it's own length, given the right circumstances, the
problem did not occur. With introduction of the incorrectly named
CoG hook the problem of rapid pitch up appeared. The pitch up was
alarming but in the main recovery was made with only a slight stain
to ones shreddies. The yaw, pitch, roll events also occurred but that
happened slowly compared to today, due to the power of the winch
being less. With wooden gliders the wing tips tended to be higher
and sufficient bank to touch the ground was more obvious, it
happened from time to time but again was scary but seldom fatal.
With the introduction of low wing glass gliders and powerful
winches that changed. We have observed the result but failed to
really identify the cause. Wing drop is a symptom certainly but
maybe not the cause, and the same applies to the yaw and rapid
pitch up. I believe that there is no single cause, it is a coming
together of several factors, and an offset hook may be one. It would
appear that larger wing span increases the chances of it happening,
as does a significant crosswind component. Like spinning in, the
only person who could tell us what really happened is not able to.
Gliders drag wings along the ground and get away with it, gliders
rear up and are recovered. Gliders are yawed by a cable out of line
and climb away, there is no single factor that you can point to and
say, if this happens then that will happen.
What is clear is that the current practice of having the hand on the
release ready to pull it is not working, by the time the problem is
recognised it is too late, because of the "normal" acceleration rate of
modern winches. I am still drawn towards yaw being the root
cause, why sometimes this develops into something more serious is
the puzzle. If anyone has an answer please share it, however crazy,
in pulling it to bits we might just stumble on the solution.
>

[[email protected]]

On Tuesday, December 6, 2016 at 7:15:05 AM UTC-7, Jock Proudfoot wrote:
>

You're right, relying on the pilot pulling the release doesn't work simply because it takes too long for the pilot to react.

I think there is just one cause of ground roll accidents and it's very simple - inadequate acceleration.

A glider just wants to fly and with the wing incidence angle at about 10 degrees with the tailwheel on the ground it will do so in about 2 seconds at 1G. Unless things are badly set up beforehand, the wings will stay balanced for at least that long. Once airborne. there is no risk of a ground roll accident.

The acceleration which worked with old wooden glider just doesn't get a heavy glass glider to aileron control speed and then airborne quickly enough.

Don, you brought up the old pitch-up myth so I'll go there.

Pitch-up on acceleration can only happen with the tailwheel in the air and that can only happen if the glider is slowly dragged into the air with feeble acceleration and THEN strong acceleration applied. It can't happen if strong acceleration is applied at the very start of the ground roll and maintained until the glider reaches the normal airspeed for rotating into the climb.

I could go on at length about this but I wrote a long paper on it available here https://dl.dropboxusercontent.com/u/79580374/Acceleration.pdf Rather than take my word for it, I very strongly suggest the BGA and other national clubs do their own investigation using tension loggers. What you will see may terrify you.

[Jim White[_3_]]

At 01:59 14 December 2016, wrote:

>Don, you brought up the old pitch-up myth so I'll go there.
>
>Pitch-up on acceleration can only happen with the tailwheel in the air
and
>=
>that can only happen if the glider is slowly dragged into the air with
>feeb=
>le acceleration and THEN strong acceleration applied. It can't happen if
>s=
>trong acceleration is applied at the very start of the ground roll and
>main=
>tained until the glider reaches the normal airspeed for rotating into the
>c=
>limb.
>
>I could go on at length about this but I wrote a long paper on it
>available=
> here https://dl.dropboxusercontent.com/u/79580374/Acceleration.pdf
Rather
>=
>than take my word for it, I very strongly suggest the BGA and other
>nationa=
>l clubs do their own investigation using tension loggers. What you will
>se=
>e may terrify you.
>

Hi Bill. If you follow URAS you will see that Don, whilst old and wise,
doesn't speak for the UK gliding community.

[Ventus_a]

On Tuesday, December 6, 2016 at 7:15:05 AM UTC-7, Jock Proudfoot wrote:


You're right, relying on the pilot pulling the release doesn't work simply because it takes too long for the pilot to react.

I think there is just one cause of ground roll accidents and it's very simple - inadequate acceleration.

A glider just wants to fly and with the wing incidence angle at about 10 degrees with the tailwheel on the ground it will do so in about 2 seconds at 1G. Unless things are badly set up beforehand, the wings will stay balanced for at least that long. Once airborne. there is no risk of a ground roll accident.

The acceleration which worked with old wooden glider just doesn't get a heavy glass glider to aileron control speed and then airborne quickly enough.

Don, you brought up the old pitch-up myth so I'll go there.

Pitch-up on acceleration can only happen with the tailwheel in the air and that can only happen if the glider is slowly dragged into the air with feeble acceleration and THEN strong acceleration applied. It can't happen if strong acceleration is applied at the very start of the ground roll and maintained until the glider reaches the normal airspeed for rotating into the climb.

I could go on at length about this but I wrote a long paper on it available here https://dl.dropboxusercontent.com/u/79580374/Acceleration.pdf Rather than take my word for it, I very strongly suggest the BGA and other national clubs do their own investigation using tension loggers. What you will see may terrify you.

Hi Bill

An excellent paper and one that I will be sharing. It tallys with my own observations from watching multiple higher acceleration winch launches of a PW-5. In all cases the tail wheel hit the ground with the acceleration and with the stick neutral the glider lifted off in a shallow climb with a slow controlled rotation with increasing speed till it was in the full climb at around 150'

As described in your paper, the most dangerous winch launches I have seen and experienced have been ones with slow acceleration

Regards
Colin

[Terry Walsh[_2_]]

At 09:19 14 December 2016, Jim White wrote:
>At 01:59 14 December 2016, wrote:
>
>>Don, you brought up the old pitch-up myth so I'll go there.
>>
>>Pitch-up on acceleration can only happen with the tailwheel in the ai
>and
>>=
>>that can only happen if the glider is slowly dragged into the air with
>>feeb=
>>le acceleration and THEN strong acceleration applied. It can't happen
if
>>s=
>>trong acceleration is applied at the very start of the ground roll and
>>main=
>>tained until the glider reaches the normal airspeed for rotating into
the
>>c=
>>limb.
>>
>>I could go on at length about this but I wrote a long paper on it
>>available=
>> here https://dl.dropboxusercontent.com/u/79580374/Acceleration.pd
>Rather
>>=
>>than take my word for it, I very strongly suggest the BGA and
other
>>nationa=
>>l clubs do their own investigation using tension loggers. What you will
>>se=
>>e may terrify you.
>>
>
>Hi Bill. If you follow URAS you will see that Don, whilst old and wise
>doesn't speak for the UK gliding community.
>
Hi Bill,

The theory may be correct but I can assure you that a K18 ALWAYS needs the
application of almost full forward stck after lift off to prevent over
rotation. This is using a powerful V8 winch with about 2 seconds of ground
roll. Yes the accleration is still happening after lift off. With a narrow
steel drum throttle response is never instantaneous due to inertia of the
drum, even with the powerful (300 hp+) V8.

[Don Johnstone[_4_]]

At 10:30 14 December 2016, Terry Walsh wrote:
>At 09:19 14 December 2016, Jim White wrote:
>>At 01:59 14 December 2016,
wrote:
>>
>>>Don, you brought up the old pitch-up myth so I'll go there.
>>>
>>>Pitch-up on acceleration can only happen with the tailwheel in
the ai
>>and
>>>=
>>>that can only happen if the glider is slowly dragged into the air
with
>>>feeb=
>>>le acceleration and THEN strong acceleration applied. It can't
happe
>if
>>>s=
>>>trong acceleration is applied at the very start of the ground roll
and
>>>main=
>>>tained until the glider reaches the normal airspeed for rotating
int
>the
>>>c=
>>>limb.
>>>
>>>I could go on at length about this but I wrote a long paper on it
>>>available=
>>> here
https://dl.dropboxusercontent.com/u/79580374/Acceleration.pd
>>Rather
>>>=
>>>than take my word for it, I very strongly suggest the BGA and
>other
>>>nationa=
>>>l clubs do their own investigation using tension loggers. What
you will
>>>se=
>>>e may terrify you.
>>>
>>
>>Hi Bill. If you follow URAS you will see that Don, whilst old and
wise
>>doesn't speak for the UK gliding community.
>>
>Hi Bill,
>
>The theory may be correct but I can assure you that a K18
ALWAYS needs th
>application of almost full forward stck after lift off to prevent ove
>rotation. This is using a powerful V8 winch with about 2 seconds
of groun
>roll. Yes the accleration is still happening after lift off. With a
narro
>steel drum throttle response is never instantaneous due to inertia
of th
>drum, even with the powerful (300 hp+) V8.
>
I believe there is a solution to this, one which no one will like, but
which would reduce the frequency of the accidents, unfortunately it
may also very expensive and difficult to achieve on existing aircraft
and would result in a reduction in winch launch height. Move the
launch hook forward.

[[email protected]]

It is pointless to enter into any sort of winch launching discussion here that is based on decades of experience by thousands of European pilots.

[B4soaring]

At 09:35 14 December 2016, Ventus_a wrote:
>
;934125 Wrote:
>> On Tuesday, December 6, 2016 at 7:15:05 AM UTC-7, Jock
Proudfoot wrote:
>>
>>
>> You're right, relying on the pilot pulling the release doesn't wor
>> simply because it takes too long for the pilot to react
>>
>> I think there is just one cause of ground roll accidents and it's
ver
>> simple - inadequate acceleration.
>>
>> A glider just wants to fly and with the wing incidence angle at
about 1
>> degrees with the tailwheel on the ground it will do so in about
>> seconds at 1G. Unless things are badly set up beforehand, the
wing
>> will stay balanced for at least that long. Once airborne. there is
n
>> risk of a ground roll accident
>>
>> The acceleration which worked with old wooden glider just
doesn't get
>> heavy glass glider to aileron control speed and then airborne
quickl
>> enough
>>
>> Don, you brought up the old pitch-up myth so I'll go there
>>
>> Pitch-up on acceleration can only happen with the tailwheel in
the ai
>> and that can only happen if the glider is slowly dragged into the
ai
>> with feeble acceleration and THEN strong acceleration applied.
It can'
>> happen if strong acceleration is applied at the very start of the
groun
>> roll and maintained until the glider reaches the normal airspeed
fo
>> rotating into the climb
>>
>> I could go on at length about this but I wrote a long paper on i
>> available her
>>
https://dl.dropboxusercontent.com/u/79580374/Acceleration.pdf
Rathe
>> than take my word for it, I very strongly suggest the BGA and
othe
>> national clubs do their own investigation using tension loggers.
Wha
>> you will see may terrify you
>
>Hi Bil
>
>An excellent paper and one that I will be sharing. It tallys with m
>own observations from watching multiple higher acceleration winc
>launches of a PW-5. In all cases the tail wheel hit the ground with
th
>acceleration and with the stick neutral the glider lifted off in
>shallow climb with a slow controlled rotation with increasing speed
til
>it was in the full climb at around 150
>
>As described in your paper, the most dangerous winch launches I
hav
>seen and experienced have been ones with slow acceleratio
>
>Regard
>Coli
>
>
>
>
>--
>Ventus_a
>

The tailwheel hitting the ground is normal for all gliders that sit on
a nosewheel and happens because the CofG is higher than the
winch hook. It has nothing to do with the rate of acceleration.
Taking off into a shallow climb with the elevator neutral is what I
would call normal acceleration.

Bill's pdf shows something completely different. The pilot is holding
the stick too far back in the early stages of launch & the elevator is
pushing the tailwheel down on to the ground even after the
mainwheel has taken off. That's just poor technique & usually
happens because the pilot is behind the aircraft & blindly pulling
back after the glider starts moving.

[[email protected]]

Bill's pdf shows something completely different. The pilot is holding
the stick too far back in the early stages of launch & the elevator is
pushing the tailwheel down on to the ground even after the
mainwheel has taken off. That's just poor technique & usually
happens because the pilot is behind the aircraft & blindly pulling
back after the glider starts moving.

A Discus is a "taildrager" which normally sits tailwheel-down.

[B4soaring]

At 22:45 14 December 2016, wrote:
>Bill's pdf shows something completely different. The pilot is holding
>the stick too far back in the early stages of launch & the elevator is
>pushing the tailwheel down on to the ground even after the
>mainwheel has taken off. That's just poor technique & usually
>happens because the pilot is behind the aircraft & blindly pulling
>back after the glider starts moving.
>
>A Discus is a "taildrager" which normally sits tailwheel-down.
>

Of course it is.

If a Discus pilot follows the technique recommended in the flight
manual then the tailplane will raise the tailwheel off the ground before
the glider takes off. Having the tailwheel rolling along the ground with
the mainwheel several feet in the air is not, and never should be,
considered a normal winch launch.

[[email protected]]

Having the tailwheel rolling along the ground with
> the mainwheel several feet in the air is not, and never should be,
> considered a normal winch launch.

Absolutely true, but counter-intuitively, the only way this could happen is with low acceleration. High acceleration means high rope tension which acts to pull the nose down if the tailwheel is still rolling.

If you look at videos of winch launch takeoffs frame-by-frame you'll find that it's not unusual to see the main wheel a few centimeters off the ground while the tailwheel is still rolling on the runway. The ASK-21 photo in the paper is typical of this. The duration of a "spur roll" is usually only a few frames of video so it's very hard to catch with a still camera.

One can get these videos with a YouTube downloader. Then, the file can be played back frame-by-frame.

[JS]

On Wednesday, December 14, 2016 at 6:30:11 PM UTC-8, wrote:
> Having the tailwheel rolling along the ground with
> > the mainwheel several feet in the air is not, and never should be,
> > considered a normal winch launch.
>
> Absolutely true, but counter-intuitively, the only way this could happen is with low acceleration. High acceleration means high rope tension which acts to pull the nose down if the tailwheel is still rolling.
>

....Or perhaps any acceleration with C/G near the aft limit?
Experienced a "good looking" start if you didn't notice the stick full forward until airborne.
Still enjoy winch launching. We should do more of it.
Jim

[David Salmon[_3_]]

At 12:09 14 December 2016, Don Johnstone wrote:
>At 10:30 14 December 2016, Terry Walsh wrote:
>>At 09:19 14 December 2016, Jim White wrote:
>>>At 01:59 14 December 2016,
>wrote:
>>>
>>>>Don, you brought up the old pitch-up myth so I'll go there.
>>>>
>>>>Pitch-up on acceleration can only happen with the tailwheel in
>the ai
>>>and
>>>>=
>>>>that can only happen if the glider is slowly dragged into the air
>with
>>>>feeb=
>>>>le acceleration and THEN strong acceleration applied. It can't
>happe
>>if
>>>>s=
>>>>trong acceleration is applied at the very start of the ground roll
>and
>>>>main=
>>>>tained until the glider reaches the normal airspeed for rotating
>int
>>the
>>>>c=
>>>>limb.
>>>>
>>>>I could go on at length about this but I wrote a long paper on it
>>>>available=
>>>> here
>https://dl.dropboxusercontent.com/u/79580374/Acceleration.pd
>>>Rather
>>>>=
>>>>than take my word for it, I very strongly suggest the BGA and
>>other
>>>>nationa=
>>>>l clubs do their own investigation using tension loggers. What
>you will
>>>>se=
>>>>e may terrify you.
>>>>
>>>
>>>Hi Bill. If you follow URAS you will see that Don, whilst old and
>wise
>>>doesn't speak for the UK gliding community.
>>>
>>Hi Bill,
>>
>>The theory may be correct but I can assure you that a K18
>ALWAYS needs th
>>application of almost full forward stck after lift off to prevent ove
>>rotation. This is using a powerful V8 winch with about 2 seconds
>of groun
>>roll. Yes the accleration is still happening after lift off. With a
>narro
>>steel drum throttle response is never instantaneous due to inertia
>of th
>>drum, even with the powerful (300 hp+) V8.
>>
>I believe there is a solution to this, one which no one will like, but
>which would reduce the frequency of the accidents, unfortunately it
>may also very expensive and difficult to achieve on existing aircraft
>and would result in a reduction in winch launch height. Move the
>launch hook forward.
>
>
>
I've picked this one up rather late, and probably like Don, I have many
thousands of winch launches, in vintage gliders, modern gliders, gliders
with compromise hooks, and with C of G hooks, initially on Tost, not
exactly underpowered, and for the last 20 years on Skylaunch, certainly not
underpowered.
To comment on something Bill said, I have analysed quite a few, from 1 sec
logger traces (perhaps not the most accurate way, but all I've got), and
find initial acceleration to be nearer .6g/.7g, rather than 1g. Tost weak
links are approximately 1.3 times auw, so should take 1g , at least when
new.
The problem with the wing going down is I think, that the pilot can be
unaware. A long time ago I had a 19m Jantar, with a compromise well forward
hook, and a loop of cord attached to the release toggle, because you could
not reach it. One day I took a launch, when I got back a few hours later, a
fellow instructor asked if I knew that the wing had gone down, so hard that
everyone at the launch point turned to look. I probably had 1500 hours on
that glider alone, and quite a few hundred launches in it, but hadn't a
clue anything had happened. To me it was a normal launch, and I got away
with it.
I totally agree though that high acceleration is good, the opposite is not.
Again, years ago, probably in the Jantar again, I had a very slow ground
run, but got away. When I got back, I found that a subsequent launch in an
ASW27, had had a wing down accident, substantial damage, fortunately no
injury. Though not there to see it, I always put that down to a slow ground
run like mine.
Most of the early Schleicher gliders, K8, K18, K6, do need a forward stick
position at the start, unlike most others, when neutral is best. The glider
will aviate when ready, it doesn't need encouraging by the pilot.
Winch launching is not inherently dangerous, any more than walking down the
street is dangerous, unless something goes wrong. Not sure without checking
how many are done in the UK each year without incident, but it runs into
hundreds of thousands. Just a very few go wrong.
What I would like to see is a re-think on launch speeds. High speed is
safe, low speed is not. Yet we have ridiculous situations like the Puchacz,
which I think is otherwise the best training glider available, with a
maximum of 59 kts, yet not really safe on a winch launch below 55 kts. This
is a fully aerobatic, inverted flight glider!!!
With the Skylaunch, perhaps others, the throttle stop is set to suit the
wind and the glider. The driver then advances the throttle lever to that
stop over a second or two. I would like to see a completely computerised
system, whereby the wind profile and the glider are selected, and the
driver just presses a button to launch, and all the parameters are built
in, including initial acceleration, surely not that difficult with modern
technology. Obviously there must be a dead man's handle.
Dave

[[email protected]]

On Tuesday, December 6, 2016 at 6:15:05 AM UTC-8, Jock Proudfoot wrote:
>

When I started flying a 19meter Kestrel years ago (on aerotow) I quickly found I could not reliably keep my wings level at the start of the aerotow launch if I looked straight ahead, because the ailerons were so inneffective at low speed. So when we started to move, I looked directly left or right towards one wing, for the first few seconds. That made it much easier to keep the wings level, although it usually needed full aileron inputs initially.. My tailwheel Kestrel would initially roll straight ahead wth the tailwheel on the ground, so there was no need to look ahead. It just needed a few seconds to gain reasonable aileron effectiveness, then I could look ahead again.

[[email protected]]

On Thursday, December 15, 2016 at 10:30:28 AM UTC-7, wrote:
> On Tuesday, December 6, 2016 at 6:15:05 AM UTC-8, Jock Proudfoot wrote:
> >
>
> When I started flying a 19meter Kestrel years ago (on aerotow) I quickly found I could not reliably keep my wings level at the start of the aerotow launch if I looked straight ahead, because the ailerons were so inneffective at low speed. So when we started to move, I looked directly left or right towards one wing, for the first few seconds. That made it much easier to keep the wings level, although it usually needed full aileron inputs initially. My tailwheel Kestrel would initially roll straight ahead wth the tailwheel on the ground, so there was no need to look ahead. It just needed a few seconds to gain reasonable aileron effectiveness, then I could look ahead again.

OK, now that we're off on tangents, here's another.

I once flew with a pilot checking out on winch launch who always applied full-right aileron as soon as the acceleration set in - often to the point the right tip nearly dragged. I asked why he was doing that. He replied that he "felt" the left wing was dropping. Video of the takeoff showed the wings level until he slammed the stick over to the right. He was baffled still insisting he "felt" a strong left wing drop.

Eventually, an AME found this individual had a left-right asymmetry in his vestibular organs which, apparently, caused him to experience a sensation of roll under linear acceleration.

This story shows why one must use visual cues and not "feel" to keep the wings level. It also shows the value of making videos of takeoffs.

[B4soaring]

At 02:30 15 December 2016, wrote:
>Having the tailwheel rolling along the ground with=20
>> the mainwheel several feet in the air is not, and never should be,=20
>> considered a normal winch launch.
>
>Absolutely true, but counter-intuitively, the only way this could happen
>is with low acceleration. High acceleration means high rope tension
which
>acts to pull the nose down if the tailwheel is still rolling.
>

Not really. Where you go wrong is assuming that the tailwheel is the centre
of rotation -
it isn't, it's an arm hitting a limit.

>If you look at videos of winch launch takeoffs frame-by-frame you'll find
>that it's not unusual to see the main wheel a few centimeters off the
>ground while the tailwheel is still rolling on the runway. The ASK-21
photo in
>the paper is typical of this. The duration of a "spur roll" is usually
>onlya few frames of video so it's very hard to catch with a still camera.
>
>One can get these videos with a YouTube downloader. Then, the file can
be
>played back frame-by-frame.
>
>

[[email protected]]

On Sunday, December 18, 2016 at 9:45:10 PM UTC-7, B4soaring wrote:

> Not really. Where you go wrong is assuming that the tailwheel is the centre
> of rotation - > it isn't, it's an arm hitting a limit.

Same difference. When an arm hits a limit, the center of rotation shifts to the contact point.

[Martin Gregorie[_5_]]

On Mon, 19 Dec 2016 12:11:35 -0800, Bill.Daniels wrote:

> On Sunday, December 18, 2016 at 9:45:10 PM UTC-7, B4soaring wrote:
>
>> Not really. Where you go wrong is assuming that the tailwheel is the
>> centre of rotation - > it isn't, it's an arm hitting a limit.
>
> Same difference. When an arm hits a limit, the center of rotation
> shifts to the contact point.

Here's a different approach to winch training.

I learnt to fly on a winch (Supacat, with a 240 hp high-torque diesel V8
providing the grunt) initially in an ASK-21 and a G103 with an Puchacz
added to the mix on my 20th launch. Pre-solo, the only aero tows I had
were flight zero (the trial flight in Front Royale's ASK-21 that set the
gliding hook) and flight 25 in the Puchacz for spin demos. The rest of my
pre-solo spin training was off the winch followed by thermal climbs to a
safe height. It was a good, thermally summer.

But I digress. The way I was taught to launch nosewheel gliders on a
winch was to start with enough back stick to raise the nose-wheel after a
few metres and, once it was off, to ease the stick forward to balance on
the main wheel until the glider lifts off. Putting the tail wheel down
was frowned on as being an unnecessarily violent rotation. The same style
works just as well for those gliders on the rather more powerful Skylaunch
that replaced the Supacat.

Similarly, in dry taildraggers I aim to lift off in the ground roll
attitude and maintain that attitude until the airspeed passes 50 kts with
definite acceleration. After that the glider is rotated into the full
climb attitude: no or poor acceleration means don't rotate.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |