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How to get maximum height on a winch launch?



 
 
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  #1  
Old December 16th 06, 11:33 PM posted to rec.aviation.soaring
Derek Copeland
external usenet poster
 
Posts: 65
Default How to get maximum height on a winch launch?

I thought that was exactly the point I was trying to
make! Stick position is type dependent. Where you hold
the stick and how much you have to pull back, or push
forward, may be different to what you are used to,
if you fly a different type of glider. It depends on
the hook position, the exact c of g and centre of pressure,
and the trim position. The advice I gave was to hold
the stick in a position that gives the optimum angle
of climb for your type of winch. Full stop, period!

Real life winch launching takes place using different
types of gliders in differing wind strengths. No one
throttle setting can cover all cases. If you launched
a slow glider (e.g. a K8) into a 45 knot headwind,
you could stop the winch altogether once it has got
airborne and allow it to launch like a kite. The wind
would be providing the energy while the winch would
just act as an anchor point on the ground. Conversely
launching a heavy two seater on a still day with a
moderately powerful winch might require absolutely
full throttle.

Derek Copeland

At 18:12 16 December 2006, Ian wrote:

Dan G wrote:
Ian wrote:


And that was a surprise? Find yourself another club,
man, because if
headwinds on a winch launch are unexpected your current
lot are going
to damage someone one day.


Easy now, my club has a long safety record any would
be proud of. AFAIK
there's never been a winch launch accident. In that
particular example
there was a very strong wind gradient. I was using
as an illustration
of the belief that K21s can take everything the winch
gives.


I am glad to hear about the safety record. I only hope
they can keep
it.

No. I think it's bad advice. Yes, you should aim
to have a proper climb
angle and air speed, but the stick position is irrelevant.
Just use
enough to do what's needed.


Well, 'find what stick position will hold them at
about 45 degrees to
the horizon AND give a safe speed' and 'you should
aim to have a proper
climb angle and air speed' seems to be the same thing...


No, they are completely different. Stick position is
irrelevant. All
that matters is whether you need to move it.

Let me give a simple example. The exact position of
the temperature
lever on a shower doesn't matter, does it? If it's
too hot you move it
'cold' a bit and if it's too cold you move it 'hot'
a bit. You don't
say 'I'll have a position 5 shower, no matter how hot
that is'.

Same with the stick.

Ian





  #2  
Old December 20th 16, 05:02 PM posted to rec.aviation.soaring
[email protected]
external usenet poster
 
Posts: 1
Default How to get maximum height on a winch launch?

On Saturday, December 16, 2006 at 3:33:08 PM UTC-8, Derek Copeland wrote:
I thought that was exactly the point I was trying to
make! Stick position is type dependent. Where you hold
the stick and how much you have to pull back, or push
forward, may be different to what you are used to,
if you fly a different type of glider. It depends on
the hook position, the exact c of g and centre of pressure,
and the trim position. The advice I gave was to hold
the stick in a position that gives the optimum angle
of climb for your type of winch. Full stop, period!

Real life winch launching takes place using different
types of gliders in differing wind strengths. No one
throttle setting can cover all cases. If you launched
a slow glider (e.g. a K8) into a 45 knot headwind,
you could stop the winch altogether once it has got
airborne and allow it to launch like a kite. The wind
would be providing the energy while the winch would
just act as an anchor point on the ground. Conversely
launching a heavy two seater on a still day with a
moderately powerful winch might require absolutely
full throttle.

Derek Copeland

At 18:12 16 December 2006, Ian wrote:

Dan G wrote:
Ian wrote:


And that was a surprise? Find yourself another club,
man, because if
headwinds on a winch launch are unexpected your current
lot are going
to damage someone one day.

Easy now, my club has a long safety record any would
be proud of. AFAIK
there's never been a winch launch accident. In that
particular example
there was a very strong wind gradient. I was using
as an illustration
of the belief that K21s can take everything the winch
gives.


I am glad to hear about the safety record. I only hope
they can keep
it.

No. I think it's bad advice. Yes, you should aim
to have a proper climb
angle and air speed, but the stick position is irrelevant.
Just use
enough to do what's needed.

Well, 'find what stick position will hold them at
about 45 degrees to
the horizon AND give a safe speed' and 'you should
aim to have a proper
climb angle and air speed' seems to be the same thing...


No, they are completely different. Stick position is
irrelevant. All
that matters is whether you need to move it.

Let me give a simple example. The exact position of
the temperature
lever on a shower doesn't matter, does it? If it's
too hot you move it
'cold' a bit and if it's too cold you move it 'hot'
a bit. You don't
say 'I'll have a position 5 shower, no matter how hot
that is'.

Same with the stick.

Ian



looking for a used winch or plans for making one.
thank you ray
  #3  
Old December 20th 16, 09:18 PM posted to rec.aviation.soaring
AS
external usenet poster
 
Posts: 653
Default How to get maximum height on a winch launch?



looking for a used winch or plans for making one.
thank you ray


Ray - join the Yahoo forum 'Winchdesign'. There you will find probably the most concentrated winch related knowledge in the world.
Where in the world are you located? There are a good number of winches for sale on the German server:
http://www.segelflug.de/osclass/inde...&sCategory=107

Uli
Winchmeister of the Carolina Soaring Association
  #4  
Old December 20th 16, 09:58 PM posted to rec.aviation.soaring
Don Johnstone[_4_]
external usenet poster
 
Posts: 398
Default How to get maximum height on a winch launch?

At 23:33 16 December 2006, Derek Copeland wrote:
I thought that was exactly the point I was trying to
make! Stick position is type dependent. Where you hold
the stick and how much you have to pull back, or push
forward, may be different to what you are used to,
if you fly a different type of glider. It depends on
the hook position, the exact c of g and centre of pressure,
and the trim position. The advice I gave was to hold
the stick in a position that gives the optimum angle
of climb for your type of winch. Full stop, period!

Real life winch launching takes place using different
types of gliders in differing wind strengths. No one
throttle setting can cover all cases. If you launched
a slow glider (e.g. a K8) into a 45 knot headwind,
you could stop the winch altogether once it has got
airborne and allow it to launch like a kite. The wind
would be providing the energy while the winch would
just act as an anchor point on the ground. Conversely
launching a heavy two seater on a still day with a
moderately powerful winch might require absolutely
full throttle.

Derek Copeland

Yep, what he said.
If you take a winch launch with a really skilled winch driver you will
experience a constant speed all the way up the launch. How is that
done? There are a combination of things that can give clues to the
winch driver, the bow in the cable, if it is wire, does not work so
well with dynema/sky rope. Marked throttle settings as on a
Skylaunch winch can help but it really is a matter of feel and
experience. For most glass gliders 55-65kts seems to work best.
I always reduce power at the top, back to idle once the glider gets
near to the max angle, instigating a back release, this avoids the
possibility of a loop if the cable is released under tension. It is
absolutely essential to ensure that the power is cut, before the
glider is vertically over the winch in nil/very low headwind
conditions, it is very unpleasant to have 1000ftl of cable drop on top
of the winch, it it can take a bit of time to get it off as well.


  #5  
Old December 21st 16, 12:59 AM posted to rec.aviation.soaring
[email protected]
external usenet poster
 
Posts: 51
Default How to get maximum height on a winch launch?

On Tuesday, December 20, 2016 at 3:00:06 PM UTC-7, Don Johnstone wrote:
At 23:33 16 December 2006, Derek Copeland wrote:
I thought that was exactly the point I was trying to
make! Stick position is type dependent. Where you hold
the stick and how much you have to pull back, or push
forward, may be different to what you are used to,
if you fly a different type of glider. It depends on
the hook position, the exact c of g and centre of pressure,
and the trim position. The advice I gave was to hold
the stick in a position that gives the optimum angle
of climb for your type of winch. Full stop, period!

Real life winch launching takes place using different
types of gliders in differing wind strengths. No one
throttle setting can cover all cases. If you launched
a slow glider (e.g. a K8) into a 45 knot headwind,
you could stop the winch altogether once it has got
airborne and allow it to launch like a kite. The wind
would be providing the energy while the winch would
just act as an anchor point on the ground. Conversely
launching a heavy two seater on a still day with a
moderately powerful winch might require absolutely
full throttle.

Derek Copeland

Yep, what he said.
If you take a winch launch with a really skilled winch driver you will
experience a constant speed all the way up the launch. How is that
done? There are a combination of things that can give clues to the
winch driver, the bow in the cable, if it is wire, does not work so
well with dynema/sky rope. Marked throttle settings as on a
Skylaunch winch can help but it really is a matter of feel and
experience. For most glass gliders 55-65kts seems to work best.
I always reduce power at the top, back to idle once the glider gets
near to the max angle, instigating a back release, this avoids the
possibility of a loop if the cable is released under tension. It is
absolutely essential to ensure that the power is cut, before the
glider is vertically over the winch in nil/very low headwind
conditions, it is very unpleasant to have 1000ftl of cable drop on top
of the winch, it it can take a bit of time to get it off as well.


If you know how to fly you can have exactly the airspeed you want all the way up the launch.

The winch does not and, in fact, cannot control glider airspeed. The pilot is the only one who can do that. The winch merely controls power (think thrust). It works exactly as with airplanes, pitch controls airspeed and power (thrust) controls rate of climb. The pilot merely adjusts pitch attitude as necessary to maintain the desired airspeed.

Reduce winch power and the rate of climb (angle) decreases but the airspeed is unchanged. Reduce it all the way to zero and the glider is left in a glide at the desired airspeed. Increase power and the rate of climb (angle) increases but the airspeed stays the same. Increase it too much and the weak link breaks - at exactly the desired airspeed - or the glider runs out of up elevator and the pilot must then ask for less power.

It's really very simple.
  #6  
Old December 21st 16, 11:36 AM posted to rec.aviation.soaring
Don Johnstone[_4_]
external usenet poster
 
Posts: 398
Default How to get maximum height on a winch launch?

At 00:59 21 December 2016,
wrote:
On Tuesday, December 20, 2016 at 3:00:06 PM UTC-7, Don

Johnstone wrote:
At 23:33 16 December 2006, Derek Copeland wrote:
I thought that was exactly the point I was trying to
make! Stick position is type dependent. Where you hold
the stick and how much you have to pull back, or push
forward, may be different to what you are used to,
if you fly a different type of glider. It depends on
the hook position, the exact c of g and centre of pressure,
and the trim position. The advice I gave was to hold
the stick in a position that gives the optimum angle
of climb for your type of winch. Full stop, period!

Real life winch launching takes place using different
types of gliders in differing wind strengths. No one
throttle setting can cover all cases. If you launched
a slow glider (e.g. a K8) into a 45 knot headwind,
you could stop the winch altogether once it has got
airborne and allow it to launch like a kite. The wind
would be providing the energy while the winch would
just act as an anchor point on the ground. Conversely
launching a heavy two seater on a still day with a
moderately powerful winch might require absolutely
full throttle.

Derek Copeland

Yep, what he said.
If you take a winch launch with a really skilled winch driver you

will=20
experience a constant speed all the way up the launch. How is

that=20
done? There are a combination of things that can give clues to

the=20
winch driver, the bow in the cable, if it is wire, does not work

so=20
well with dynema/sky rope. Marked throttle settings as on a=20
Skylaunch winch can help but it really is a matter of feel

and=20
experience. For most glass gliders 55-65kts seems to work

best.
I always reduce power at the top, back to idle once the glider

gets=20
near to the max angle, instigating a back release, this avoids

the=20
possibility of a loop if the cable is released under tension. It

is=20
absolutely essential to ensure that the power is cut, before

the=20
glider is vertically over the winch in nil/very low headwind=20
conditions, it is very unpleasant to have 1000ftl of cable drop

on top=20
of the winch, it it can take a bit of time to get it off as well.


If you know how to fly you can have exactly the airspeed you want

all the
w=
ay up the launch. =20

The winch does not and, in fact, cannot control glider airspeed.

The
pilot=
is the only one who can do that. The winch merely controls

power (think
t=
hrust). It works exactly as with airplanes, pitch controls airspeed

and
po=
wer (thrust) controls rate of climb. The pilot merely adjusts pitch
attitu=
de as necessary to maintain the desired airspeed.

Reduce winch power and the rate of climb (angle) decreases but

the
airspeed=
is unchanged. Reduce it all the way to zero and the glider is left

in a
g=
lide at the desired airspeed. Increase power and the rate of climb
(angle)=
increases but the airspeed stays the same. Increase it too much

and the
w=
eak link breaks - at exactly the desired airspeed - or the glider

runs out
=
of up elevator and the pilot must then ask for less power.

It's really very simple.


Ha Ha, good one. Not done much winching then Bill


  #8  
Old December 21st 16, 02:10 PM posted to rec.aviation.soaring
Peter F[_2_]
external usenet poster
 
Posts: 56
Default How to get maximum height on a winch launch?

Actually if we had better designed winches Bill would be correct.

Unfortunately the gliding movement certainly in the UK, but also in Europe,
seems to have taken the "Easy" option of Skylaunch winches.
400hp and auto Transmission mean that the pilot has little control of the
airspeed during the launch.

Too fast? ease back, go even faster!

PF

At 13:01 21 December 2016, Andreas Maurer wrote:
On Tue, 20 Dec 2016 16:59:34 -0800 (PST),
wrote:


If you know how to fly you can have exactly the airspeed you want all

the
way up the launch.

The winch does not and, in fact, cannot control glider airspeed. The

pilot is the only one who can do that. The winch merely controls power
(think thrust). It works exactly as with airplanes, pitch controls
airspeed and power (thrust) controls rate of climb. The pilot merely
adjusts pitch attitude as necessary to maintain the desired airspeed.

Reduce winch power and the rate of climb (angle) decreases but the

airspeed is unchanged. Reduce it all the way to zero and the glider is
left in a glide at the desired airspeed. Increase power and the rate of
climb (angle) increases but the airspeed stays the same. Increase it too
much and the weak link breaks - at exactly the desired airspeed - or the
glider runs out of up elevator and the pilot must then ask for less

power.

It's really very simple.


Hi Bill,

unfortunately it's not that simple. Your description does not even
remotely match the experiences I made I made in the last couple of
thousand winch launches.

Best regards
Andreas



  #9  
Old December 21st 16, 03:39 PM posted to rec.aviation.soaring
Steve Leonard[_2_]
external usenet poster
 
Posts: 1,076
Default How to get maximum height on a winch launch?

On Wednesday, December 21, 2016 at 8:15:04 AM UTC-6, Peter F wrote:
Actually if we had better designed winches Bill would be correct.

Unfortunately the gliding movement certainly in the UK, but also in Europe,
seems to have taken the "Easy" option of Skylaunch winches.
400hp and auto Transmission mean that the pilot has little control of the
airspeed during the launch.

Too fast? ease back, go even faster!

PF


Ah, so you took the American Approach. Nothing Exceeds like Excess! Or, there is nothing that cannot be improved with application of more cubic inches.

Steve Leonard
  #10  
Old December 21st 16, 09:23 PM posted to rec.aviation.soaring
[email protected]
external usenet poster
 
Posts: 51
Default How to get maximum height on a winch launch?

On Wednesday, December 21, 2016 at 7:15:04 AM UTC-7, Peter F wrote:
Actually if we had better designed winches Bill would be correct.

Unfortunately the gliding movement certainly in the UK, but also in Europe,
seems to have taken the "Easy" option of Skylaunch winches.
400hp and auto Transmission mean that the pilot has little control of the
airspeed during the launch.

Too fast? ease back, go even faster!

PF



400HP is good. Automatic transmissions are evil.
 




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