Decision making in ground roll

On 3/24/21 8:56 PM, ProfJ wrote:
Hi Folks,

There's a lot of focus at the moment on wing dropping during the
ground roll phase. I did my primary training on winch launches. For
those who have never winch launched, it's quite an experience being
in a 900 lb. vehicle which is accelerated by a 300hp motor which is
fixed to the ground and connected by a cable, i.e. no slip anywhere.
One of my co-trainees was a large and apparently fearless
professional rugby player; some time later he admitted to me that he
had kept his eyes tightly closed for his first half dozen launches.

As a way of dealing with the sensory overload of the first few
seconds of a winch launch, I used a protocol which was based on what
I could control. It went like this:

In the first second of roll, there is only one control which has any
authority, and that is the cable release. You have to release if the
glider jerks forward and overruns the cable. So, have a good grip on
the release and the only thing you have to think about in the first
second is, should I release? None of the other controls have any
effect at this speed, so don't think about them.

In the second second of roll, the rudder starts to have authority.
The initial jerk probably pulled the glider offline. So get back on
line. Given the yaw/roll coupling, this will probably help raise any
falling wingtip.

In the third second of roll, the elevator has authority. So raise
the tail (or nose, depending) and get balanced on the main wheel.

You might question, why control yaw then roll? Even with two wheels
on the ground, there is some yaw control, and the initial launch jerk
probably has the tail bobbing up and down anyway, so don't worry
about pitch yet. Get in line.

In the fourth second of roll, the ailerons finally have some
authority and you can level the wings. By that time, with a winch,
you're probably airborne anyway.

This was helpful to me because it gave a structure for dealing with a
very fluid and rapidly evolving situation.

The main reason for describing this, is that it requires you to have
a grip on the release and understand that it's a primary control
during ground roll; certainly the only one that works in the initial
roll.

Just my two cents...


I see others have provided feedback related to the "weak point" in your
logical - and IMO fundamentally sensible - reasoning. My knee-jerk
mental response to your logic was along the lines of: It's sensible in
basic theory, but likely "only minimally applicable" to most of the real
(winching) world.

It would take some combo of a weak
winch,"leisurely-winch-operator"/lacking-headwind to yield a
4-second-to-liftoff winch launch in my direct/observational
experience...writing as one whose first experience with a winch was a
1948, Buick straight-8-powered, old/tired when our paths crossed
baby...and *IT* easily, consistently, bettered 4-seconds-to-liftoff
launches of loaded 2-33s.

In any event, if your logical/linear reasoning worked for you - awesome!
Mebbe the problem lies in translating reality to words, I dunno. But
sensory-input overload is an inescapable hurdle teaching/experiencing
winch launching contains to be sure. There's no substitute for
experience...assuming a person survives it.

YMMV.

Bob W.

On Thursday, 25 March 2021 at 08:33:54 UTC-6, Bob W. wrote:
On 3/24/21 8:56 PM, ProfJ wrote:
Hi Folks,

There's a lot of focus at the moment on wing dropping during the
ground roll phase. I did my primary training on winch launches. For
those who have never winch launched, it's quite an experience being
in a 900 lb. vehicle which is accelerated by a 300hp motor which is
fixed to the ground and connected by a cable, i.e. no slip anywhere.
One of my co-trainees was a large and apparently fearless
professional rugby player; some time later he admitted to me that he
had kept his eyes tightly closed for his first half dozen launches.

As a way of dealing with the sensory overload of the first few
seconds of a winch launch, I used a protocol which was based on what
I could control. It went like this:

In the first second of roll, there is only one control which has any
authority, and that is the cable release. You have to release if the
glider jerks forward and overruns the cable. So, have a good grip on
the release and the only thing you have to think about in the first
second is, should I release? None of the other controls have any
effect at this speed, so don't think about them.

In the second second of roll, the rudder starts to have authority.
The initial jerk probably pulled the glider offline. So get back on
line. Given the yaw/roll coupling, this will probably help raise any
falling wingtip.

In the third second of roll, the elevator has authority. So raise
the tail (or nose, depending) and get balanced on the main wheel.

You might question, why control yaw then roll? Even with two wheels
on the ground, there is some yaw control, and the initial launch jerk
probably has the tail bobbing up and down anyway, so don't worry
about pitch yet. Get in line.

In the fourth second of roll, the ailerons finally have some
authority and you can level the wings. By that time, with a winch,
you're probably airborne anyway.

This was helpful to me because it gave a structure for dealing with a
very fluid and rapidly evolving situation.

The main reason for describing this, is that it requires you to have
a grip on the release and understand that it's a primary control
during ground roll; certainly the only one that works in the initial
roll.

Just my two cents...

I see others have provided feedback related to the "weak point" in your
logical - and IMO fundamentally sensible - reasoning. My knee-jerk
mental response to your logic was along the lines of: It's sensible in
basic theory, but likely "only minimally applicable" to most of the real
(winching) world.

It would take some combo of a weak
winch,"leisurely-winch-operator"/lacking-headwind to yield a
4-second-to-liftoff winch launch in my direct/observational
experience...writing as one whose first experience with a winch was a
1948, Buick straight-8-powered, old/tired when our paths crossed
baby...and *IT* easily, consistently, bettered 4-seconds-to-liftoff
launches of loaded 2-33s.

In any event, if your logical/linear reasoning worked for you - awesome!
Mebbe the problem lies in translating reality to words, I dunno. But
sensory-input overload is an inescapable hurdle teaching/experiencing
winch launching contains to be sure. There's no substitute for
experience...assuming a person survives it.

YMMV.

Bob W.

It's kind of fun to have all the experts invalidate my actual lived experience, and also physics. Let's go watch some videos of winch launches, shall we?

Here's Bruno Vassel launching https://www.youtube.com/watch?v=VrUT...el=BrunoVassel . Due to the wonders of actual video evidence, we see the glider taking seven seconds from first roll to airborne.
Here's one from Oxford Gliding - https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer - nine seconds from first movement to airborne.
Here's one from Mount Beauty - https://www.youtube.com/watch?v=SE5J...=GeorgeSkarbek - five seconds to airborne.
Here's one - called "Rather fast winch launch" ! - https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer - five seconds to airborne.

I didn't cherry-pick these, they were the first four I found where you could see the glider roll. If anyone can find one showing a two-second roll, go ahead and show us.

Yes, it seems like it's two seconds. That's the problem of sensory overload. Apparently even the experience of 1500 launches on a variety of airfields doesn't overcome it.

On Friday, 26 March 2021 at 10:25:39 UTC-6, ProfJ wrote:
On Thursday, 25 March 2021 at 08:33:54 UTC-6, Bob W. wrote:
On 3/24/21 8:56 PM, ProfJ wrote:
Hi Folks,

There's a lot of focus at the moment on wing dropping during the
ground roll phase. I did my primary training on winch launches. For
those who have never winch launched, it's quite an experience being
in a 900 lb. vehicle which is accelerated by a 300hp motor which is
fixed to the ground and connected by a cable, i.e. no slip anywhere.
One of my co-trainees was a large and apparently fearless
professional rugby player; some time later he admitted to me that he
had kept his eyes tightly closed for his first half dozen launches.

As a way of dealing with the sensory overload of the first few
seconds of a winch launch, I used a protocol which was based on what
I could control. It went like this:

In the first second of roll, there is only one control which has any
authority, and that is the cable release. You have to release if the
glider jerks forward and overruns the cable. So, have a good grip on
the release and the only thing you have to think about in the first
second is, should I release? None of the other controls have any
effect at this speed, so don't think about them.

In the second second of roll, the rudder starts to have authority.
The initial jerk probably pulled the glider offline. So get back on
line. Given the yaw/roll coupling, this will probably help raise any
falling wingtip.

In the third second of roll, the elevator has authority. So raise
the tail (or nose, depending) and get balanced on the main wheel.

You might question, why control yaw then roll? Even with two wheels
on the ground, there is some yaw control, and the initial launch jerk
probably has the tail bobbing up and down anyway, so don't worry
about pitch yet. Get in line.

In the fourth second of roll, the ailerons finally have some
authority and you can level the wings. By that time, with a winch,
you're probably airborne anyway.

This was helpful to me because it gave a structure for dealing with a
very fluid and rapidly evolving situation.

The main reason for describing this, is that it requires you to have
a grip on the release and understand that it's a primary control
during ground roll; certainly the only one that works in the initial
roll.

Just my two cents...

I see others have provided feedback related to the "weak point" in your
logical - and IMO fundamentally sensible - reasoning. My knee-jerk
mental response to your logic was along the lines of: It's sensible in
basic theory, but likely "only minimally applicable" to most of the real
(winching) world.

It would take some combo of a weak
winch,"leisurely-winch-operator"/lacking-headwind to yield a
4-second-to-liftoff winch launch in my direct/observational
experience...writing as one whose first experience with a winch was a
1948, Buick straight-8-powered, old/tired when our paths crossed
baby...and *IT* easily, consistently, bettered 4-seconds-to-liftoff
launches of loaded 2-33s.

In any event, if your logical/linear reasoning worked for you - awesome!
Mebbe the problem lies in translating reality to words, I dunno. But
sensory-input overload is an inescapable hurdle teaching/experiencing
winch launching contains to be sure. There's no substitute for
experience...assuming a person survives it.

YMMV.

Bob W.
It's kind of fun to have all the experts invalidate my actual lived experience, and also physics. Let's go watch some videos of winch launches, shall we?

Here's Bruno Vassel launching https://www.youtube.com/watch?v=VrUT...el=BrunoVassel . Due to the wonders of actual video evidence, we see the glider taking seven seconds from first roll to airborne.
Here's one from Oxford Gliding - https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer - nine seconds from first movement to airborne.
Here's one from Mount Beauty - https://www.youtube.com/watch?v=SE5J...=GeorgeSkarbek - five seconds to airborne.
Here's one - called "Rather fast winch launch" ! - https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer - five seconds to airborne.

I didn't cherry-pick these, they were the first four I found where you could see the glider roll. If anyone can find one showing a two-second roll, go ahead and show us.

Yes, it seems like it's two seconds. That's the problem of sensory overload. Apparently even the experience of 1500 launches on a variety of airfields doesn't overcome it.

Oh yeah, and those videos which have cockpit view - note the hand on the release. Tango Whiskey, you better let Bruno know he's doing it all wrong...

On Fri, 26 Mar 2021 09:27:45 -0700 (PDT), ProfJ
wrote:

Oh yeah, and those videos which have cockpit view - note the hand on the release. Tango Whiskey, you better let Bruno know he's doing it all wrong...

Keeping the hand on the release is doing it all wrong, sorry to say
that. Seen a couple of incidents caused by inadvertent release.

Before you ask - I see about 3.000 winch launches per year on my home
airfield alone. This is probably more than all the winch launches in
the US combined, hence I reckon us Germans have a little bit of
experience with that launch method...


Cheers from Germany
Andreas

On 3/26/2021 12:25 PM, ProfJ wrote:
On Thursday, 25 March 2021 at 08:33:54 UTC-6, Bob W. wrote:
On 3/24/21 8:56 PM, ProfJ wrote:
Hi Folks,

There's a lot of focus at the moment on wing dropping during the
ground roll phase. I did my primary training on winch launches. For
those who have never winch launched, it's quite an experience being
in a 900 lb. vehicle which is accelerated by a 300hp motor which is
fixed to the ground and connected by a cable, i.e. no slip anywhere.
One of my co-trainees was a large and apparently fearless
professional rugby player; some time later he admitted to me that he
had kept his eyes tightly closed for his first half dozen launches.

As a way of dealing with the sensory overload of the first few
seconds of a winch launch, I used a protocol which was based on what
I could control. It went like this:

In the first second of roll, there is only one control which has any
authority, and that is the cable release. You have to release if the
glider jerks forward and overruns the cable. So, have a good grip on
the release and the only thing you have to think about in the first
second is, should I release? None of the other controls have any
effect at this speed, so don't think about them.

In the second second of roll, the rudder starts to have authority.
The initial jerk probably pulled the glider offline. So get back on
line. Given the yaw/roll coupling, this will probably help raise any
falling wingtip.

In the third second of roll, the elevator has authority. So raise
the tail (or nose, depending) and get balanced on the main wheel.

You might question, why control yaw then roll? Even with two wheels
on the ground, there is some yaw control, and the initial launch jerk
probably has the tail bobbing up and down anyway, so don't worry
about pitch yet. Get in line.

In the fourth second of roll, the ailerons finally have some
authority and you can level the wings. By that time, with a winch,
you're probably airborne anyway.

This was helpful to me because it gave a structure for dealing with a
very fluid and rapidly evolving situation.

The main reason for describing this, is that it requires you to have
a grip on the release and understand that it's a primary control
during ground roll; certainly the only one that works in the initial
roll.

Just my two cents...

I see others have provided feedback related to the "weak point" in your
logical - and IMO fundamentally sensible - reasoning. My knee-jerk
mental response to your logic was along the lines of: It's sensible in
basic theory, but likely "only minimally applicable" to most of the real
(winching) world.

It would take some combo of a weak
winch,"leisurely-winch-operator"/lacking-headwind to yield a
4-second-to-liftoff winch launch in my direct/observational
experience...writing as one whose first experience with a winch was a
1948, Buick straight-8-powered, old/tired when our paths crossed
baby...and *IT* easily, consistently, bettered 4-seconds-to-liftoff
launches of loaded 2-33s.

In any event, if your logical/linear reasoning worked for you - awesome!
Mebbe the problem lies in translating reality to words, I dunno. But
sensory-input overload is an inescapable hurdle teaching/experiencing
winch launching contains to be sure. There's no substitute for
experience...assuming a person survives it.

YMMV.

Bob W.

It's kind of fun to have all the experts invalidate my actual lived experience, and also physics. Let's go watch some videos of winch launches, shall we?

Here's Bruno Vassel launching https://www.youtube.com/watch?v=VrUT...el=BrunoVassel . Due to the wonders of actual video evidence, we see the glider taking seven seconds from first roll to airborne.
Here's one from Oxford Gliding - https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer - nine seconds from first movement to airborne.
Here's one from Mount Beauty - https://www.youtube.com/watch?v=SE5J...=GeorgeSkarbek - five seconds to airborne.
Here's one - called "Rather fast winch launch" ! - https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer - five seconds to airborne.

I didn't cherry-pick these, they were the first four I found where you could see the glider roll. If anyone can find one showing a two-second roll, go ahead and show us.

Yes, it seems like it's two seconds. That's the problem of sensory overload. Apparently even the experience of 1500 launches on a variety of airfields doesn't overcome it.

Never let mere facts get in the way of a good theory!

On Fri, 26 Mar 2021 13:37:25 -0400, Moshe Braner wrote:

On 3/26/2021 12:25 PM, ProfJ wrote:
On Thursday, 25 March 2021 at 08:33:54 UTC-6, Bob W. wrote:
On 3/24/21 8:56 PM, ProfJ wrote:
Hi Folks,

There's a lot of focus at the moment on wing dropping during the
ground roll phase. I did my primary training on winch launches. For
those who have never winch launched, it's quite an experience being
in a 900 lb. vehicle which is accelerated by a 300hp motor which is
fixed to the ground and connected by a cable, i.e. no slip anywhere.
One of my co-trainees was a large and apparently fearless
professional rugby player; some time later he admitted to me that he
had kept his eyes tightly closed for his first half dozen launches.

As a way of dealing with the sensory overload of the first few
seconds of a winch launch, I used a protocol which was based on what
I could control. It went like this:

In the first second of roll, there is only one control which has any
authority, and that is the cable release. You have to release if the
glider jerks forward and overruns the cable. So, have a good grip on
the release and the only thing you have to think about in the first
second is, should I release? None of the other controls have any
effect at this speed, so don't think about them.

In the second second of roll, the rudder starts to have authority.
The initial jerk probably pulled the glider offline. So get back on
line. Given the yaw/roll coupling, this will probably help raise any
falling wingtip.

In the third second of roll, the elevator has authority. So raise the
tail (or nose, depending) and get balanced on the main wheel.

You might question, why control yaw then roll? Even with two wheels
on the ground, there is some yaw control, and the initial launch jerk
probably has the tail bobbing up and down anyway, so don't worry
about pitch yet. Get in line.

In the fourth second of roll, the ailerons finally have some
authority and you can level the wings. By that time, with a winch,
you're probably airborne anyway.

This was helpful to me because it gave a structure for dealing with a
very fluid and rapidly evolving situation.

The main reason for describing this, is that it requires you to have
a grip on the release and understand that it's a primary control
during ground roll; certainly the only one that works in the initial
roll.

Just my two cents...

I see others have provided feedback related to the "weak point" in
your logical - and IMO fundamentally sensible - reasoning. My
knee-jerk mental response to your logic was along the lines of: It's
sensible in basic theory, but likely "only minimally applicable" to
most of the real (winching) world.

It would take some combo of a weak
winch,"leisurely-winch-operator"/lacking-headwind to yield a
4-second-to-liftoff winch launch in my direct/observational
experience...writing as one whose first experience with a winch was a
1948, Buick straight-8-powered, old/tired when our paths crossed
baby...and *IT* easily, consistently, bettered 4-seconds-to-liftoff
launches of loaded 2-33s.

In any event, if your logical/linear reasoning worked for you -
awesome!
Mebbe the problem lies in translating reality to words, I dunno. But
sensory-input overload is an inescapable hurdle teaching/experiencing
winch launching contains to be sure. There's no substitute for
experience...assuming a person survives it.

YMMV.

Bob W.

It's kind of fun to have all the experts invalidate my actual lived
experience, and also physics. Let's go watch some videos of winch
launches, shall we?

Here's Bruno Vassel launching
https://www.youtube.com/watch?v=VrUT...el=BrunoVassel .
Due to the wonders of actual video evidence, we see the glider taking
seven seconds from first roll to airborne.
Here's one from Oxford Gliding -
https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer -
nine seconds from first movement to airborne.
Here's one from Mount Beauty -
https://www.youtube.com/watch?v=SE5J...=GeorgeSkarbek -
five seconds to airborne.
Here's one - called "Rather fast winch launch" ! -
https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer -
five seconds to airborne.

I didn't cherry-pick these, they were the first four I found where you
could see the glider roll. If anyone can find one showing a two-second
roll, go ahead and show us.

Yes, it seems like it's two seconds. That's the problem of sensory
overload. Apparently even the experience of 1500 launches on a variety
of airfields doesn't overcome it.

Never let mere facts get in the way of a good theory!

....but all the same, all those launches look like those we had back in
2000 when I was learning to fly. That was a Supacat with steel cables,
which take much more power to pull in when the cable is still on the
ground than the plastic cable we use now. That winch had a 250hp aircooled
diesel V8 engine that I'm told was designed for pumping water to keep
mines dry.

Now we have a 400 hp Skylaunch (V8 truck engine running on LPG and fitted
with plastic cables, and initial acceleration is a LOT faster.

We use a 1km cable: when we were using steel cable even six men pulling
it couldn't pull the cable back after an aborted launch: we just told the
winch driver the wind it in and put the glider on the next cable.
However, with the plastic cable we use now, in the same situation two
blokes can pull the cable back the the launch point without difficulty.
That large difference in the effort needed to pull the cable along the
ground makes a huge difference to the initial launch acceleration.

I think the UK and Australian videos all showed winches using steel
cable. I can't see what winch or type of cable Bruno was using, but he
did mention 8000 feet of cable while the others all looked to be quite a
lot shorter.



--
Martin | martin at
Gregorie | gregorie dot org

I attended a winch training a few years ago. I had aero-tow only prior. Of course, it was stressed to release if the wing dropped. This particular winch was pretty strong and we were airborne rapidly. I remember thinking that, by the time I realized the wing was dropping and reacted to it, we would be tumbling down the runway. It was only 10 launches over couple of days and I still wasn't over the sensory overload on #10. Hand near but not on the release, BTW. I wonder how many flights it would take me or the average pilot to get comfortable but there are limited opportunities in my neck of the woods.

On Friday, 26 March 2021 at 16:25:39 UTC, ProfJ wrote:

It's kind of fun to have all the experts invalidate my actual lived experience, and also physics. Let's go watch some videos of winch launches, shall we?

Here's Bruno Vassel launching https://www.youtube.com/watch?v=VrUT...el=BrunoVassel . Due to the wonders of actual video evidence, we see the glider taking seven seconds from first roll to airborne.
Here's one from Oxford Gliding - https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer - nine seconds from first movement to airborne.
Here's one from Mount Beauty - https://www.youtube.com/watch?v=SE5J...=GeorgeSkarbek - five seconds to airborne.
Here's one - called "Rather fast winch launch" ! - https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer - five seconds to airborne.

I didn't cherry-pick these, they were the first four I found where you could see the glider roll. If anyone can find one showing a two-second roll, go ahead and show us.

Yes, it seems like it's two seconds. That's the problem of sensory overload. Apparently even the experience of 1500 launches on a variety of airfields doesn't overcome it.

This one at my club shows the glider in the air after about 2 seconds:

https://www.youtube.com/watch?v=f_ASzIsviAE

On 3/26/2021 5:13 PM, waremark wrote:
On Friday, 26 March 2021 at 16:25:39 UTC, ProfJ wrote:

It's kind of fun to have all the experts invalidate my actual lived
experience, and also physics. Let's go watch some videos of winch
launches, shall we?

Here's Bruno Vassel launching
https://www.youtube.com/watch?v=VrUT...el=BrunoVassel . Due
to the wonders of actual video evidence, we see the glider taking seven
seconds from first roll to airborne. Here's one from Oxford Gliding -
https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer - nine
seconds from first movement to airborne. Here's one from Mount Beauty -
https://www.youtube.com/watch?v=SE5J...=GeorgeSkarbek -
five seconds to airborne. Here's one - called "Rather fast winch launch"
! - https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer -
five seconds to airborne.

I didn't cherry-pick these, they were the first four I found where you
could see the glider roll. If anyone can find one showing a two-second
roll, go ahead and show us.

Yes, it seems like it's two seconds. That's the problem of sensory
overload. Apparently even the experience of 1500 launches on a variety of
airfields doesn't overcome it.

This one at my club shows the glider in the air after about 2 seconds:

https://www.youtube.com/watch?v=f_ASzIsviAE


Reality is what a person experiences; camera views aren't 100% representative
(cf: Hollywood).

A beady-eyed look at several of the Mt. Beauty launch views-from-afar show
multiple launches with ~2-sec ground rolls *after* the line slack is removed
and the ship is beyond wing-runner assistance...which by my reckoning is "when
the winch launch begins". Everything prior to that is preparation.

YMMV.

Bob W.

On Saturday, March 27, 2021 at 8:34:29 AM UTC-4, Bob Whelan wrote:
On 3/26/2021 5:13 PM, waremark wrote:
On Friday, 26 March 2021 at 16:25:39 UTC, ProfJ wrote:

It's kind of fun to have all the experts invalidate my actual lived
experience, and also physics. Let's go watch some videos of winch
launches, shall we?

Here's Bruno Vassel launching
https://www.youtube.com/watch?v=VrUT...el=BrunoVassel . Due
to the wonders of actual video evidence, we see the glider taking seven
seconds from first roll to airborne. Here's one from Oxford Gliding -
https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer - nine
seconds from first movement to airborne. Here's one from Mount Beauty -
https://www.youtube.com/watch?v=SE5J...=GeorgeSkarbek -
five seconds to airborne. Here's one - called "Rather fast winch launch"
! - https://www.youtube.com/watch?v=-eTU...nel=GreatFlyer -
five seconds to airborne.

I didn't cherry-pick these, they were the first four I found where you
could see the glider roll. If anyone can find one showing a two-second
roll, go ahead and show us.

Yes, it seems like it's two seconds. That's the problem of sensory
overload. Apparently even the experience of 1500 launches on a variety of
airfields doesn't overcome it.

This one at my club shows the glider in the air after about 2 seconds:

https://www.youtube.com/watch?v=f_ASzIsviAE

Reality is what a person experiences; camera views aren't 100% representative
(cf: Hollywood).

A beady-eyed look at several of the Mt. Beauty launch views-from-afar show
multiple launches with ~2-sec ground rolls *after* the line slack is removed
and the ship is beyond wing-runner assistance...which by my reckoning is "when
the winch launch begins". Everything prior to that is preparation.

YMMV.

Bob W.

Bob - couldn't agree more with your separation between 'preparation' and 'winch launch begins'.
I wanted to point out the Design Guidelines for the design and approval of a glider winch issued by the DAeC in Germany, of which I made a full translation which got 'lost' by the old Yahoo winchdesign group administration when they shut them down:

https://www.daec.de/fileadmin/user_u...2010_Rev02.pdf

Original Text:
Paragraph 2115: Beschleunigungsnachweis
Bei Windstille muss das zu startende Luftfahrzeug nach einer
Beschleunigungsstrecke von 15 m um die Längsachse steuerbar sein und
nach höchstens weiteren 45 m Beschleunigungsstrecke die
Abhebegeschwindigkeit erreicht haben.
Der Roll- und Luftwiderstand, sowie die Seilreibung am Boden müssen
beim rechnerischen Nachweis durch einen Zuschlag von 30%
berücksichtigt werden. Der Zuschlag kann bei der Verwendung von
Kunststoffseilen auf 10% vermindert werden.

Translation:
Acceleration requirements
In clam air, the glider to be launched must have control around the longitudinal axis [i.e. aileron control] after a distance of 15m and must have reached lift-off speed after a further 45m.
Rolling- and air resistance as well as the cable friction against the ground have to be considered in the calculations by a factor of 1.3. This additional friction factor can be reduced to 1.1 when plastic lines are being used.

There are more paragraphs governing the speed and power requirements.
What that means is that any winch designed and built either commercially or by clubs in Germany must comply with these guidelines or else they will not get approved and therefore their operation would be illegal and not covered by by the club's insurance. (The DAeC guidelines are de facto the law, similar to BGA regulations in the UK)
When we (a few winch enthusiasts and I ) started the discussion group winchdesign almost 20 years ago and I provided a full translation of these guidelines (with the written permission of the DAeC), it was the general consensus that having guidelines like this makes perfect sense and avoids most hazardous conditions during the winch launch.

So, if ProfJ sees winches accelerating the gliders in a very anemic way it could mean that either the operator is not doing his/her job correctly or the winch is not designed in accordance with these guidelines, which is very possible since many winches around the world were designed in accordance with the rule 'Hold my beer - watch this!'
But of course issuing strict and heavy-handed guidelines based on sound engineering and physics in the interest of operational safety like these must be just another example of a socialist government stifling individualism and free expression, right? ;-)

Uli
'AS'