SAFE Winch Launching

In article
,
bildan wrote:

On Jul 11, 2:00*am, Derek Copeland wrote:

At my club we typically get about 1600ft in no wind and
2000ft launching into a 10 knot headwind. Our standard aerotows are 2000ft,
but you can go as high as you like, depending on your needs and the depth
of your wallet.

This week we were getting as high as 1900' from 3900 feet of rope at
9000 feet density altitude with little wind with the Hydrowinch. With
no gear shifting at all, the Hydrowinch is MUCH smoother than any
winch with an automatic transmission.

Skylaunches are just like old Gerhleins with new paint - they use
exactly the same components. They are not particularly well
controlled since they use road vehicle torque converters and automatic
transmissions free to shift gears when they please. The old junk
Gerhleins around most US clubs are probably the only winches in the
world worse than a Skylaunch - but they are a LOT cheaper.

BTW, notice how Derek has to reply to himself to get any conversation
at all?

My club used to have a very good winch. It was a one-off called the
"Eagle Winch" and was designed and built by one of our members. He got
his initial glider training in Germany and had knowledge of quality
winches. That winch is now with the Philadelphia Glider Council, I
believe. We were forced to let go of it because we moved to a municipal
airport that was incompatible with winch operations (crossing runways).

The Eagle winch has an automatic transmission. However, in our operation
it was locked into 2nd gear for normal conditions. In strong wind, we
used 1st gear. No gear changes necessary. It was very easy to operate
and became even more so after the steel cable was swapped our for plasma
rope by the second owners at the Memphis club. At our original field,
with 4000 feet of cable out, we could easily launch our single seaters
to 2000 feet if we had any headwind.

On Jul 11, 11:45*am, Berry wrote:
In article
,



*bildan wrote:
On Jul 11, 2:00*am, Derek Copeland wrote:

At my club we typically get about 1600ft in no wind and
2000ft launching into a 10 knot headwind. Our standard aerotows are 2000ft,
but you can go as high as you like, depending on your needs and the depth
of your wallet.

This week we were getting as high as 1900' from 3900 feet of rope at
9000 feet density altitude with little wind with the Hydrowinch. *With
no gear shifting at all, the Hydrowinch is MUCH smoother than any
winch with an automatic transmission.

Skylaunches are just like old Gerhleins with new paint - they use
exactly the same components. *They are not particularly well
controlled since they use road vehicle torque converters and automatic
transmissions free to shift gears when they please. *The old junk
Gerhleins around most US clubs are probably the only winches in the
world worse than a Skylaunch - but they are a LOT cheaper.

BTW, notice how Derek has to reply to himself to get any conversation
at all?

My club used to have a very good winch. It was a one-off called the
"Eagle Winch" and was designed and built by one of our members. He got
his initial glider training in Germany and had knowledge of quality
winches. That winch is now with the Philadelphia Glider Council, I
believe. We were forced to let go of it because we moved to a municipal
airport that was incompatible with winch operations (crossing runways).

The Eagle winch has an automatic transmission. However, in our operation
it was locked into 2nd gear for normal conditions. In strong wind, we
used 1st gear. No gear changes necessary. It was very easy to operate
and became even more so after the steel cable was swapped our for plasma
rope by the second owners at the Memphis club. At our original field,
with 4000 feet of cable out, we could easily launch our single seaters
to 2000 feet if we had any headwind.

Germany is a good place to learn about winches. Plasma rope is like
night and day compared to steel. Steel cable is evil stuff. If you
have a winch actually designed for Plasma - unlike the Skylaunch and
Gerhlein - it will outlast steel by as much as 5x making it actually
cheaper in the long run.

Did you actually lock your transmission in 2nd or just place the gear
selector in 2nd? It's an important question since a standard tranny
will still make the 1-2 upshift causing a power oscillation. We see
a lot of tension traces showing tension oscillations from these
winches.

Anyone considering an automatic transmission for a gilder winch really
needs to understand how they work. Automatics are highly developed
for road vehicles whose requirements are diametrically opposed to
those of a glider winch. If a road vehicle encounters an increasing
load, such as a hill, it is designed to help the driver maintain speed
by increasing torque to the wheels to meet the higher load, doing what
it can to reduce the loss of speed. Cresting the hill and starting
down, it reduces torque and tends toward coasting. Both actions
increase vehicle performance and minimize fuel consumption.

If a glider encounters a thermal during a launch, the rope tension
will increase which the automatic transmission will see as a "hill"
causing it to increase torque to the drum. This increases rope
tension still more as it tries to pull the glider down through the
thermal. If the glider hits sink, the automatic transmission will
slack off the torque just when the glider needs more power. A good
winch operator can overcome these to a degree with constant throttle
adjustments - if he can tell what is going on in the glider but it's
hard, skilled work. It's definitely not "set and forget".

A tension controlled winch will do the opposite - decreasing power in
thermals letting lift do the work and increasing it in sink leaving
the pilot to control speed with pitch. The pilot sees a very smooth
launch regardless of wind or thermals. The winch operator doesn't
need to do anything at all.

It's wonderful to never need speed signals again.

On Sat, 11 Jul 2009 17:07:50 -0700 (PDT), bildan
wrote:

A tension controlled winch will do the opposite - decreasing power in
thermals letting lift do the work and increasing it in sink leaving
the pilot to control speed with pitch. The pilot sees a very smooth
launch regardless of wind or thermals. The winch operator doesn't
need to do anything at all.

It's wonderful to never need speed signals again.


.... yet thousands of clubs in Europe with much, much more winch
experience than any club in the US don't see the need for such a
system.

Bills explanation a couple of posts ago is an excellent and simple
description of how it constant tension works and why it would be
beneficial.

Why don't we in Europe adopt this technology -- quite simply cost.
Without private finance of money/time/labour/parts few clubs if any can
afford to scrap their current winches and buy the new technology.

Dave

At 00:29 12 July 2009, Andreas Maurer wrote:
On Sat, 11 Jul 2009 17:07:50 -0700 (PDT), bildan
wrote:

A tension controlled winch will do the opposite - decreasing power in
thermals letting lift do the work and increasing it in sink leaving
the pilot to control speed with pitch. The pilot sees a very smooth
launch regardless of wind or thermals. The winch operator doesn't
need to do anything at all.

It's wonderful to never need speed signals again.


.... yet thousands of clubs in Europe with much, much more winch
experience than any club in the US don't see the need for such a
system.

On 12 Jul 2009 10:15:03 GMT, Dave Martin
wrote:

Bills explanation a couple of posts ago is an excellent and simple
description of how it constant tension works and why it would be
beneficial.

Why don't we in Europe adopt this technology -- quite simply cost.
Without private finance of money/time/labour/parts few clubs if any can
afford to scrap their current winches and buy the new technology.

If constant tension was really necessary for a good winch launch, many
clubs would already have one.
But the standard system (Tost, Skylaunch, whatever) is good enough for
the majority aof the clubs here.

It's definitely nicve to have - but Bill would probably have an easier
job if he advertized a more simple and much cheaper winch design to
the US clubs...

Hi,

A tension controlled winch will do the opposite

... yet thousands of clubs in Europe with much, much more winch
experience than any club in the US don't see the need for such a
system.

Some do.

When I was trained as a winch driver I was taught to judge cable tension
and use that as the input parameter to the control loop. The only way of
doing that without special sensors is to look at the cable sag. Works
during the main portion of the launch, but is not very accurate of course.

I think if the winch, or winch driver, has the means to control tension
and the pilot controls airspeed winch launches become more efficient and
even safer. Reports suggest that, I have no experience of my own.

Also you would propably get much more consistent launch performance
across different conditions and much more important, different drivers.
Today we get launches like being shot from a carrier deck and the
lumbering wingrunner-testing type all in the same day depending on who
is manning the winch. The first launches of the day, or after a driver
swap, or when conditions change would no longer need to be different
than those by a well-adapted driver.

I am all for it.

Ciao, MM

On Sun, 12 Jul 2009 12:45:08 +0200, Marian Aldenhövel
wrote:


... yet thousands of clubs in Europe with much, much more winch
experience than any club in the US don't see the need for such a
system.

Some do.

Indceed some do - but very, very few.
If there really was an urgent need we'd have more than a couple of
such winches in Europe by now, don't you agree?

When I was trained as a winch driver I was taught to judge cable tension
and use that as the input parameter to the control loop. The only way of
doing that without special sensors is to look at the cable sag. Works
during the main portion of the launch, but is not very accurate of course.

But sufficiently accurate, isn't it?
Contrary to the believe of some people here it doesn't matter if the
speed during the winch launch is 5 kts faster or slower (although the
perfect speed certainly increases launch height).

I think if the winch, or winch driver, has the means to control tension
and the pilot controls airspeed winch launches become more efficient and
even safer. Reports suggest that, I have no experience of my own.

Efficiency? Definitely.
Safety? I doubt it.
I havent't been able to find even one accident report that was caused
by inappropriate power setting by the winch driver, yet there are
comparably many accidents caused by rope breaks or complete power
losses of the winch - things that cannot be prevented by tension
controlled speed.


Also you would propably get much more consistent launch performance
across different conditions and much more important, different drivers.

Indeed. Nice to have.

Today we get launches like being shot from a carrier deck and the
lumbering wingrunner-testing type all in the same day depending on who
is manning the winch. The first launches of the day, or after a driver
swap, or when conditions change would no longer need to be different
than those by a well-adapted driver.

Typical problem of winch driver training. Once we started to re-train
our winch drivers who had problem scontroling the speed, we got rid of
this problem.


Viele Grüße
Andreas

I would love to fly a tension controlled winch we were launhing today in
to strong head winds increasing rapidly part way up the launch. I can
imagine it is better, but I am not an expert.

Winch safety is mostly in the hands of the pilot, the winch is not
relevant to a good launch, but the trained pilot must be able to react to
any scenario.

But other nonsense posted here . please help me, ...

A standard car auto gearbox has some magic power to automatically adjust
the torque to the car wheels on reaching a hill, without changing gear,
road speed or engine setting? What magic is that?

David.


At 18:45 12 July 2009, Andreas Maurer wrote:
On Sun, 12 Jul 2009 12:45:08 +0200, Marian Aldenhövel
wrote:


... yet thousands of clubs in Europe with much, much more winch
experience than any club in the US don't see the need for such a
system.

Some do.

Indceed some do - but very, very few.
If there really was an urgent need we'd have more than a couple of
such winches in Europe by now, don't you agree?

When I was trained as a winch driver I was taught to judge cable tension

and use that as the input parameter to the control loop. The only way of

doing that without special sensors is to look at the cable sag. Works
during the main portion of the launch, but is not very accurate of
course.

But sufficiently accurate, isn't it?
Contrary to the believe of some people here it doesn't matter if the
speed during the winch launch is 5 kts faster or slower (although the
perfect speed certainly increases launch height).

I think if the winch, or winch driver, has the means to control tension

and the pilot controls airspeed winch launches become more efficient and

even safer. Reports suggest that, I have no experience of my own.

Efficiency? Definitely.
Safety? I doubt it.
I havent't been able to find even one accident report that was caused
by inappropriate power setting by the winch driver, yet there are
comparably many accidents caused by rope breaks or complete power
losses of the winch - things that cannot be prevented by tension
controlled speed.


Also you would propably get much more consistent launch performance
across different conditions and much more important, different drivers.


Indeed. Nice to have.

Today we get launches like being shot from a carrier deck and the
lumbering wingrunner-testing type all in the same day depending on who
is manning the winch. The first launches of the day, or after a driver
swap, or when conditions change would no longer need to be different
than those by a well-adapted driver.

Typical problem of winch driver training. Once we started to re-train
our winch drivers who had problem scontroling the speed, we got rid of
this problem.


Viele Grüße
Andreas

I mis typed, ..
the winch is relevant to a good launch, but the pilot is responsible for
the safety,


At 21:30 12 July 2009, David Chapman wrote:
I would love to fly a tension controlled winch we were launhing today
in
to strong head winds increasing rapidly part way up the launch. I can
imagine it is better, but I am not an expert.

Winch safety is mostly in the hands of the pilot, the winch is not
relevant to a good launch, but the trained pilot must be able to react
to
any scenario.

But other nonsense posted here . please help me, ...

A standard car auto gearbox has some magic power to automatically adjust
the torque to the car wheels on reaching a hill, without changing gear,
road speed or engine setting? What magic is that?

David.


At 18:45 12 July 2009, Andreas Maurer wrote:
On Sun, 12 Jul 2009 12:45:08 +0200, Marian Aldenhövel
wrote:


... yet thousands of clubs in Europe with much, much more winch
experience than any club in the US don't see the need for such a
system.

Some do.

Indceed some do - but very, very few.
If there really was an urgent need we'd have more than a couple of
such winches in Europe by now, don't you agree?

When I was trained as a winch driver I was taught to judge cable
tension

and use that as the input parameter to the control loop. The only way
of

doing that without special sensors is to look at the cable sag. Works
during the main portion of the launch, but is not very accurate of
course.

But sufficiently accurate, isn't it?
Contrary to the believe of some people here it doesn't matter if the
speed during the winch launch is 5 kts faster or slower (although the
perfect speed certainly increases launch height).

I think if the winch, or winch driver, has the means to control
tension

and the pilot controls airspeed winch launches become more efficient
and

even safer. Reports suggest that, I have no experience of my own.

Efficiency? Definitely.
Safety? I doubt it.
I havent't been able to find even one accident report that was caused
by inappropriate power setting by the winch driver, yet there are
comparably many accidents caused by rope breaks or complete power
losses of the winch - things that cannot be prevented by tension
controlled speed.


Also you would propably get much more consistent launch performance
across different conditions and much more important, different
drivers.


Indeed. Nice to have.

Today we get launches like being shot from a carrier deck and the
lumbering wingrunner-testing type all in the same day depending on who

is manning the winch. The first launches of the day, or after a driver

swap, or when conditions change would no longer need to be different
than those by a well-adapted driver.

Typical problem of winch driver training. Once we started to re-train
our winch drivers who had problem scontroling the speed, we got rid of
this problem.


Viele Grüße
Andreas

On Jul 12, 3:30*pm, David Chapman
wrote:

But other nonsense posted here . please help me, *...

A standard car auto gearbox has some magic power to automatically adjust
the torque to the car wheels on reaching a hill, without changing gear,
road speed or engine setting? What magic is that?


That 'magic' is called a torque converter which begins to slip and
multiply torque under increasing load. Stock units can double torque
to the wheels.

Modern transmissions use a torque converter locking clutch allowing an
even greater torque multipication factor after the clutch disengages
under load. The effect can be 4:1 or greater.

For basic info, see: http://en.wikipedia.org/wiki/Torque_converter

In addition, automobile engine torque curves have peak torque lower
than cruise RPM. As the vehicle encounters a load such as a hill, the
torque output actually increases as the RPM is pulled down by the
increasing load. The typical V8 used in glider winches has a torque
peak at about 1800 RPM.

The engine/transmission combination acts in exact opposition to what
is needed in a glider winch.